services/surfaceflinger/SurfaceFlinger.cpp

/*
 * Copyright (C) 2007 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

// #define LOG_NDEBUG 0
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include <stdint.h>
#include <sys/types.h>
#include <algorithm>
#include <errno.h>
#include <math.h>
#include <mutex>
#include <dlfcn.h>
#include <inttypes.h>
#include <stdatomic.h>
#include <optional>

#include <cutils/properties.h>
#include <log/log.h>

#include <binder/IPCThreadState.h>
#include <binder/IServiceManager.h>
#include <binder/PermissionCache.h>

#include <dvr/vr_flinger.h>

#include <ui/ColorSpace.h>
#include <ui/DebugUtils.h>
#include <ui/DisplayInfo.h>
#include <ui/DisplayStatInfo.h>

#include <gui/BufferQueue.h>
#include <gui/GuiConfig.h>
#include <gui/IDisplayEventConnection.h>
#include <gui/IProducerListener.h>
#include <gui/LayerDebugInfo.h>
#include <gui/Surface.h>
#include <renderengine/RenderEngine.h>
#include <ui/GraphicBufferAllocator.h>
#include <ui/PixelFormat.h>
#include <ui/UiConfig.h>

#include <utils/misc.h>
#include <utils/String8.h>
#include <utils/String16.h>
#include <utils/StopWatch.h>
#include <utils/Timers.h>
#include <utils/Trace.h>

#include <private/android_filesystem_config.h>
#include <private/gui/SyncFeatures.h>

#include "BufferLayer.h"
#include "BufferQueueLayer.h"
#include "BufferStateLayer.h"
#include "Client.h"
#include "ColorLayer.h"
#include "Colorizer.h"
#include "ContainerLayer.h"
#include "DdmConnection.h"
#include "DisplayDevice.h"
#include "Layer.h"
#include "LayerVector.h"
#include "MonitoredProducer.h"
#include "NativeWindowSurface.h"
#include "StartPropertySetThread.h"
#include "SurfaceFlinger.h"
#include "SurfaceInterceptor.h"

#include "DisplayHardware/ComposerHal.h"
#include "DisplayHardware/DisplayIdentification.h"
#include "DisplayHardware/FramebufferSurface.h"
#include "DisplayHardware/HWComposer.h"
#include "DisplayHardware/VirtualDisplaySurface.h"
#include "Effects/Daltonizer.h"
#include "Scheduler/DispSync.h"
#include "Scheduler/DispSyncSource.h"
#include "Scheduler/EventControlThread.h"
#include "Scheduler/EventThread.h"
#include "Scheduler/InjectVSyncSource.h"
#include "Scheduler/MessageQueue.h"
#include "Scheduler/Scheduler.h"

#include <cutils/compiler.h>

#include "android-base/stringprintf.h"

#include <android/hardware/configstore/1.0/ISurfaceFlingerConfigs.h>
#include <android/hardware/configstore/1.1/ISurfaceFlingerConfigs.h>
#include <android/hardware/configstore/1.2/ISurfaceFlingerConfigs.h>
#include <android/hardware/configstore/1.1/types.h>
#include <configstore/Utils.h>

#include <layerproto/LayerProtoParser.h>

namespace android {

using namespace android::hardware::configstore;
using namespace android::hardware::configstore::V1_0;
using ui::ColorMode;
using ui::Dataspace;
using ui::Hdr;
using ui::RenderIntent;

namespace {

#pragma clang diagnostic push
#pragma clang diagnostic error "-Wswitch-enum"

bool isWideColorMode(const ColorMode colorMode) {
    switch (colorMode) {
        case ColorMode::DISPLAY_P3:
        case ColorMode::ADOBE_RGB:
        case ColorMode::DCI_P3:
        case ColorMode::BT2020:
        case ColorMode::DISPLAY_BT2020:
        case ColorMode::BT2100_PQ:
        case ColorMode::BT2100_HLG:
            return true;
        case ColorMode::NATIVE:
        case ColorMode::STANDARD_BT601_625:
        case ColorMode::STANDARD_BT601_625_UNADJUSTED:
        case ColorMode::STANDARD_BT601_525:
        case ColorMode::STANDARD_BT601_525_UNADJUSTED:
        case ColorMode::STANDARD_BT709:
        case ColorMode::SRGB:
            return false;
    }
    return false;
}

ui::Transform::orientation_flags fromSurfaceComposerRotation(ISurfaceComposer::Rotation rotation) {
    switch (rotation) {
        case ISurfaceComposer::eRotateNone:
            return ui::Transform::ROT_0;
        case ISurfaceComposer::eRotate90:
            return ui::Transform::ROT_90;
        case ISurfaceComposer::eRotate180:
            return ui::Transform::ROT_180;
        case ISurfaceComposer::eRotate270:
            return ui::Transform::ROT_270;
    }
    ALOGE("Invalid rotation passed to captureScreen(): %d\n", rotation);
    return ui::Transform::ROT_0;
}

#pragma clang diagnostic pop

class ConditionalLock {
public:
    ConditionalLock(Mutex& mutex, bool lock) : mMutex(mutex), mLocked(lock) {
        if (lock) {
            mMutex.lock();
        }
    }
    ~ConditionalLock() { if (mLocked) mMutex.unlock(); }
private:
    Mutex& mMutex;
    bool mLocked;
};

// Currently we only support V0_SRGB and DISPLAY_P3 as composition preference.
bool validateCompositionDataspace(Dataspace dataspace) {
    return dataspace == Dataspace::V0_SRGB || dataspace == Dataspace::DISPLAY_P3;
}

}  // namespace anonymous

// ---------------------------------------------------------------------------

const String16 sHardwareTest("android.permission.HARDWARE_TEST");
const String16 sAccessSurfaceFlinger("android.permission.ACCESS_SURFACE_FLINGER");
const String16 sReadFramebuffer("android.permission.READ_FRAME_BUFFER");
const String16 sDump("android.permission.DUMP");

// ---------------------------------------------------------------------------
int64_t SurfaceFlinger::vsyncPhaseOffsetNs;
int64_t SurfaceFlinger::sfVsyncPhaseOffsetNs;
int64_t SurfaceFlinger::dispSyncPresentTimeOffset;
bool SurfaceFlinger::useHwcForRgbToYuv;
uint64_t SurfaceFlinger::maxVirtualDisplaySize;
bool SurfaceFlinger::hasSyncFramework;
bool SurfaceFlinger::useVrFlinger;
int64_t SurfaceFlinger::maxFrameBufferAcquiredBuffers;
bool SurfaceFlinger::hasWideColorDisplay;
int SurfaceFlinger::primaryDisplayOrientation = DisplayState::eOrientationDefault;
bool SurfaceFlinger::useColorManagement;
bool SurfaceFlinger::useContextPriority;
Dataspace SurfaceFlinger::defaultCompositionDataspace = Dataspace::V0_SRGB;
ui::PixelFormat SurfaceFlinger::defaultCompositionPixelFormat = ui::PixelFormat::RGBA_8888;
Dataspace SurfaceFlinger::wideColorGamutCompositionDataspace = Dataspace::V0_SRGB;
ui::PixelFormat SurfaceFlinger::wideColorGamutCompositionPixelFormat = ui::PixelFormat::RGBA_8888;

std::string getHwcServiceName() {
    char value[PROPERTY_VALUE_MAX] = {};
    property_get("debug.sf.hwc_service_name", value, "default");
    ALOGI("Using HWComposer service: '%s'", value);
    return std::string(value);
}

bool useTrebleTestingOverride() {
    char value[PROPERTY_VALUE_MAX] = {};
    property_get("debug.sf.treble_testing_override", value, "false");
    ALOGI("Treble testing override: '%s'", value);
    return std::string(value) == "true";
}

std::string decodeDisplayColorSetting(DisplayColorSetting displayColorSetting) {
    switch(displayColorSetting) {
        case DisplayColorSetting::MANAGED:
            return std::string("Managed");
        case DisplayColorSetting::UNMANAGED:
            return std::string("Unmanaged");
        case DisplayColorSetting::ENHANCED:
            return std::string("Enhanced");
        default:
            return std::string("Unknown ") +
                std::to_string(static_cast<int>(displayColorSetting));
    }
}

SurfaceFlingerBE::SurfaceFlingerBE()
      : mHwcServiceName(getHwcServiceName()),
        mRenderEngine(nullptr),
        mFrameBuckets(),
        mTotalTime(0),
        mLastSwapTime(0),
        mComposerSequenceId(0) {
}

SurfaceFlinger::SurfaceFlinger(surfaceflinger::Factory& factory,
                               SurfaceFlinger::SkipInitializationTag)
      : BnSurfaceComposer(),
        mFactory(factory),
        mTransactionPending(false),
        mAnimTransactionPending(false),
        mLayersRemoved(false),
        mLayersAdded(false),
        mBootTime(systemTime()),
        mVisibleRegionsDirty(false),
        mGeometryInvalid(false),
        mAnimCompositionPending(false),
        mBootStage(BootStage::BOOTLOADER),
        mDebugRegion(0),
        mDebugDDMS(0),
        mDebugDisableHWC(0),
        mDebugDisableTransformHint(0),
        mDebugInTransaction(0),
        mLastTransactionTime(0),
        mForceFullDamage(false),
        mPrimaryHWVsyncEnabled(false),
        mHWVsyncAvailable(false),
        mRefreshStartTime(0),
        mHasPoweredOff(false),
        mNumLayers(0),
        mVrFlingerRequestsDisplay(false),
        mMainThreadId(std::this_thread::get_id()) {}

SurfaceFlinger::SurfaceFlinger(surfaceflinger::Factory& factory)
      : SurfaceFlinger(factory, SkipInitialization) {
    ALOGI("SurfaceFlinger is starting");

    vsyncPhaseOffsetNs = getInt64< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::vsyncEventPhaseOffsetNs>(1000000);

    sfVsyncPhaseOffsetNs = getInt64< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::vsyncSfEventPhaseOffsetNs>(1000000);

    hasSyncFramework = getBool< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::hasSyncFramework>(true);

    dispSyncPresentTimeOffset = getInt64< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::presentTimeOffsetFromVSyncNs>(0);

    useHwcForRgbToYuv = getBool< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::useHwcForRGBtoYUV>(false);

    maxVirtualDisplaySize = getUInt64<ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::maxVirtualDisplaySize>(0);

    // Vr flinger is only enabled on Daydream ready devices.
    useVrFlinger = getBool< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::useVrFlinger>(false);

    maxFrameBufferAcquiredBuffers = getInt64< ISurfaceFlingerConfigs,
            &ISurfaceFlingerConfigs::maxFrameBufferAcquiredBuffers>(2);

    hasWideColorDisplay =
            getBool<ISurfaceFlingerConfigs, &ISurfaceFlingerConfigs::hasWideColorDisplay>(false);
    useColorManagement =
            getBool<V1_2::ISurfaceFlingerConfigs,
                    &V1_2::ISurfaceFlingerConfigs::useColorManagement>(false);

    auto surfaceFlingerConfigsServiceV1_2 = V1_2::ISurfaceFlingerConfigs::getService();
    if (surfaceFlingerConfigsServiceV1_2) {
        surfaceFlingerConfigsServiceV1_2->getCompositionPreference(
                [&](auto tmpDefaultDataspace, auto tmpDefaultPixelFormat,
                    auto tmpWideColorGamutDataspace, auto tmpWideColorGamutPixelFormat) {
                    defaultCompositionDataspace = tmpDefaultDataspace;
                    defaultCompositionPixelFormat = tmpDefaultPixelFormat;
                    wideColorGamutCompositionDataspace = tmpWideColorGamutDataspace;
                    wideColorGamutCompositionPixelFormat = tmpWideColorGamutPixelFormat;
                });
    }
    mDefaultCompositionDataspace = defaultCompositionDataspace;
    mWideColorGamutCompositionDataspace = wideColorGamutCompositionDataspace;

    useContextPriority = getBool<ISurfaceFlingerConfigs,
                                 &ISurfaceFlingerConfigs::useContextPriority>(true);

    V1_1::DisplayOrientation primaryDisplayOrientation =
        getDisplayOrientation<V1_1::ISurfaceFlingerConfigs,
                              &V1_1::ISurfaceFlingerConfigs::primaryDisplayOrientation>(
            V1_1::DisplayOrientation::ORIENTATION_0);

    switch (primaryDisplayOrientation) {
        case V1_1::DisplayOrientation::ORIENTATION_90:
            SurfaceFlinger::primaryDisplayOrientation = DisplayState::eOrientation90;
            break;
        case V1_1::DisplayOrientation::ORIENTATION_180:
            SurfaceFlinger::primaryDisplayOrientation = DisplayState::eOrientation180;
            break;
        case V1_1::DisplayOrientation::ORIENTATION_270:
            SurfaceFlinger::primaryDisplayOrientation = DisplayState::eOrientation270;
            break;
        default:
            SurfaceFlinger::primaryDisplayOrientation = DisplayState::eOrientationDefault;
            break;
    }
    ALOGV("Primary Display Orientation is set to %2d.", SurfaceFlinger::primaryDisplayOrientation);

    mPrimaryDispSync =
            getFactory().createDispSync("PrimaryDispSync", SurfaceFlinger::hasSyncFramework,
                                        SurfaceFlinger::dispSyncPresentTimeOffset);

    // debugging stuff...
    char value[PROPERTY_VALUE_MAX];

    property_get("ro.bq.gpu_to_cpu_unsupported", value, "0");
    mGpuToCpuSupported = !atoi(value);

    property_get("debug.sf.showupdates", value, "0");
    mDebugRegion = atoi(value);

    property_get("debug.sf.ddms", value, "0");
    mDebugDDMS = atoi(value);
    if (mDebugDDMS) {
        if (!startDdmConnection()) {
            // start failed, and DDMS debugging not enabled
            mDebugDDMS = 0;
        }
    }
    ALOGI_IF(mDebugRegion, "showupdates enabled");
    ALOGI_IF(mDebugDDMS, "DDMS debugging enabled");

    property_get("debug.sf.disable_backpressure", value, "0");
    mPropagateBackpressure = !atoi(value);
    ALOGI_IF(!mPropagateBackpressure, "Disabling backpressure propagation");

    property_get("debug.sf.enable_hwc_vds", value, "0");
    mUseHwcVirtualDisplays = atoi(value);
    ALOGI_IF(mUseHwcVirtualDisplays, "Enabling HWC virtual displays");

    property_get("ro.sf.disable_triple_buffer", value, "1");
    mLayerTripleBufferingDisabled = atoi(value);
    ALOGI_IF(mLayerTripleBufferingDisabled, "Disabling Triple Buffering");

    const size_t defaultListSize = MAX_LAYERS;
    auto listSize = property_get_int32("debug.sf.max_igbp_list_size", int32_t(defaultListSize));
    mMaxGraphicBufferProducerListSize = (listSize > 0) ? size_t(listSize) : defaultListSize;

    property_get("debug.sf.early_phase_offset_ns", value, "-1");
    const int earlySfOffsetNs = atoi(value);

    property_get("debug.sf.early_gl_phase_offset_ns", value, "-1");
    const int earlyGlSfOffsetNs = atoi(value);

    property_get("debug.sf.early_app_phase_offset_ns", value, "-1");
    const int earlyAppOffsetNs = atoi(value);

    property_get("debug.sf.early_gl_app_phase_offset_ns", value, "-1");
    const int earlyGlAppOffsetNs = atoi(value);

    property_get("debug.sf.use_scheduler", value, "0");
    mUseScheduler = atoi(value);

    const VSyncModulator::Offsets earlyOffsets =
            {earlySfOffsetNs != -1 ? earlySfOffsetNs : sfVsyncPhaseOffsetNs,
            earlyAppOffsetNs != -1 ? earlyAppOffsetNs : vsyncPhaseOffsetNs};
    const VSyncModulator::Offsets earlyGlOffsets =
            {earlyGlSfOffsetNs != -1 ? earlyGlSfOffsetNs : sfVsyncPhaseOffsetNs,
            earlyGlAppOffsetNs != -1 ? earlyGlAppOffsetNs : vsyncPhaseOffsetNs};
    mVsyncModulator.setPhaseOffsets(earlyOffsets, earlyGlOffsets,
            {sfVsyncPhaseOffsetNs, vsyncPhaseOffsetNs});

    // We should be reading 'persist.sys.sf.color_saturation' here
    // but since /data may be encrypted, we need to wait until after vold
    // comes online to attempt to read the property. The property is
    // instead read after the boot animation

    if (useTrebleTestingOverride()) {
        // Without the override SurfaceFlinger cannot connect to HIDL
        // services that are not listed in the manifests.  Considered
        // deriving the setting from the set service name, but it
        // would be brittle if the name that's not 'default' is used
        // for production purposes later on.
        setenv("TREBLE_TESTING_OVERRIDE", "true", true);
    }
}

void SurfaceFlinger::onFirstRef()
{
    mEventQueue->init(this);
}

SurfaceFlinger::~SurfaceFlinger()
{
}

void SurfaceFlinger::binderDied(const wp<IBinder>& /* who */)
{
    // the window manager died on us. prepare its eulogy.

    // restore initial conditions (default device unblank, etc)
    initializeDisplays();

    // restart the boot-animation
    startBootAnim();
}

static sp<ISurfaceComposerClient> initClient(const sp<Client>& client) {
    status_t err = client->initCheck();
    if (err == NO_ERROR) {
        return client;
    }
    return nullptr;
}

sp<ISurfaceComposerClient> SurfaceFlinger::createConnection() {
    return initClient(new Client(this));
}

sp<ISurfaceComposerClient> SurfaceFlinger::createScopedConnection(
        const sp<IGraphicBufferProducer>& gbp) {
    if (authenticateSurfaceTexture(gbp) == false) {
        return nullptr;
    }
    const auto& layer = (static_cast<MonitoredProducer*>(gbp.get()))->getLayer();
    if (layer == nullptr) {
        return nullptr;
    }

   return initClient(new Client(this, layer));
}

sp<IBinder> SurfaceFlinger::createDisplay(const String8& displayName,
        bool secure)
{
    class DisplayToken : public BBinder {
        sp<SurfaceFlinger> flinger;
        virtual ~DisplayToken() {
             // no more references, this display must be terminated
             Mutex::Autolock _l(flinger->mStateLock);
             flinger->mCurrentState.displays.removeItem(this);
             flinger->setTransactionFlags(eDisplayTransactionNeeded);
         }
     public:
        explicit DisplayToken(const sp<SurfaceFlinger>& flinger)
            : flinger(flinger) {
        }
    };

    sp<BBinder> token = new DisplayToken(this);

    Mutex::Autolock _l(mStateLock);
    // Display ID is assigned when virtual display is allocated by HWC.
    DisplayDeviceState state;
    state.isSecure = secure;
    state.displayName = displayName;
    mCurrentState.displays.add(token, state);
    mInterceptor->saveDisplayCreation(state);
    return token;
}

void SurfaceFlinger::destroyDisplay(const sp<IBinder>& displayToken) {
    Mutex::Autolock _l(mStateLock);

    ssize_t index = mCurrentState.displays.indexOfKey(displayToken);
    if (index < 0) {
        ALOGE("destroyDisplay: Invalid display token %p", displayToken.get());
        return;
    }

    const DisplayDeviceState& state = mCurrentState.displays.valueAt(index);
    if (!state.isVirtual()) {
        ALOGE("destroyDisplay called for non-virtual display");
        return;
    }
    mInterceptor->saveDisplayDeletion(state.sequenceId);
    mCurrentState.displays.removeItemsAt(index);
    setTransactionFlags(eDisplayTransactionNeeded);
}

sp<IBinder> SurfaceFlinger::getBuiltInDisplay(int32_t id) {
    std::optional<DisplayId> displayId;

    if (id == HWC_DISPLAY_PRIMARY) {
        displayId = getInternalDisplayId();
    } else if (id == HWC_DISPLAY_EXTERNAL) {
        displayId = getExternalDisplayId();
    }

    if (!displayId) {
        ALOGE("%s: Invalid display %d", __FUNCTION__, id);
        return nullptr;
    }

    return getPhysicalDisplayToken(*displayId);
}

status_t SurfaceFlinger::getColorManagement(bool* outGetColorManagement) const {
    if (!outGetColorManagement) {
        return BAD_VALUE;
    }
    *outGetColorManagement = useColorManagement;
    return NO_ERROR;
}

void SurfaceFlinger::bootFinished()
{
    if (mStartPropertySetThread->join() != NO_ERROR) {
        ALOGE("Join StartPropertySetThread failed!");
    }
    const nsecs_t now = systemTime();
    const nsecs_t duration = now - mBootTime;
    ALOGI("Boot is finished (%ld ms)", long(ns2ms(duration)) );

    // wait patiently for the window manager death
    const String16 name("window");
    sp<IBinder> window(defaultServiceManager()->getService(name));
    if (window != 0) {
        window->linkToDeath(static_cast<IBinder::DeathRecipient*>(this));
    }

    if (mVrFlinger) {
      mVrFlinger->OnBootFinished();
    }

    // stop boot animation
    // formerly we would just kill the process, but we now ask it to exit so it
    // can choose where to stop the animation.
    property_set("service.bootanim.exit", "1");

    const int LOGTAG_SF_STOP_BOOTANIM = 60110;
    LOG_EVENT_LONG(LOGTAG_SF_STOP_BOOTANIM,
                   ns2ms(systemTime(SYSTEM_TIME_MONOTONIC)));

    postMessageAsync(new LambdaMessage([this] {
        readPersistentProperties();
        mBootStage = BootStage::FINISHED;
    }));
}

uint32_t SurfaceFlinger::getNewTexture() {
    {
        std::lock_guard lock(mTexturePoolMutex);
        if (!mTexturePool.empty()) {
            uint32_t name = mTexturePool.back();
            mTexturePool.pop_back();
            ATRACE_INT("TexturePoolSize", mTexturePool.size());
            return name;
        }

        // The pool was too small, so increase it for the future
        ++mTexturePoolSize;
    }

    // The pool was empty, so we need to get a new texture name directly using a
    // blocking call to the main thread
    uint32_t name = 0;
    postMessageSync(new LambdaMessage([&]() { getRenderEngine().genTextures(1, &name); }));
    return name;
}

void SurfaceFlinger::deleteTextureAsync(uint32_t texture) {
    postMessageAsync(new LambdaMessage([=] { getRenderEngine().deleteTextures(1, &texture); }));
}

// Do not call property_set on main thread which will be blocked by init
// Use StartPropertySetThread instead.
void SurfaceFlinger::init() {
    ALOGI(  "SurfaceFlinger's main thread ready to run. "
            "Initializing graphics H/W...");

    ALOGI("Phase offest NS: %" PRId64 "", vsyncPhaseOffsetNs);

    Mutex::Autolock _l(mStateLock);

    // start the EventThread
    if (mUseScheduler) {
        mScheduler = getFactory().createScheduler([this](bool enabled) {
            setVsyncEnabled(EventThread::DisplayType::Primary, enabled);
        });

        mAppConnectionHandle =
                mScheduler->createConnection("appConnection", SurfaceFlinger::vsyncPhaseOffsetNs,
                                             [this] { resyncWithRateLimit(); },
                                             impl::EventThread::InterceptVSyncsCallback());
        mSfConnectionHandle =
                mScheduler->createConnection("sfConnection", SurfaceFlinger::sfVsyncPhaseOffsetNs,
                                             [this] { resyncWithRateLimit(); },
                                             [this](nsecs_t timestamp) {
                                                 mInterceptor->saveVSyncEvent(timestamp);
                                             });

        mEventQueue->setEventConnection(mScheduler->getEventConnection(mSfConnectionHandle));
        mVsyncModulator.setSchedulerAndHandles(mScheduler.get(), mAppConnectionHandle.get(),
                                               mSfConnectionHandle.get());
    } else {
        mEventThreadSource =
                std::make_unique<DispSyncSource>(mPrimaryDispSync.get(),
                                                 SurfaceFlinger::vsyncPhaseOffsetNs, true, "app");
        mEventThread =
                std::make_unique<impl::EventThread>(mEventThreadSource.get(),
                                                    [this] { resyncWithRateLimit(); },
                                                    impl::EventThread::InterceptVSyncsCallback(),
                                                    "appEventThread");
        mSfEventThreadSource =
                std::make_unique<DispSyncSource>(mPrimaryDispSync.get(),
                                                 SurfaceFlinger::sfVsyncPhaseOffsetNs, true, "sf");

        mSFEventThread =
                std::make_unique<impl::EventThread>(mSfEventThreadSource.get(),
                                                    [this] { resyncWithRateLimit(); },
                                                    [this](nsecs_t timestamp) {
                                                        mInterceptor->saveVSyncEvent(timestamp);
                                                    },
                                                    "sfEventThread");
        mEventQueue->setEventThread(mSFEventThread.get());
        mVsyncModulator.setEventThreads(mSFEventThread.get(), mEventThread.get());
    }

    // Get a RenderEngine for the given display / config (can't fail)
    int32_t renderEngineFeature = 0;
    renderEngineFeature |= (useColorManagement ?
                            renderengine::RenderEngine::USE_COLOR_MANAGEMENT : 0);
    renderEngineFeature |= (useContextPriority ?
                            renderengine::RenderEngine::USE_HIGH_PRIORITY_CONTEXT : 0);

    // TODO(b/77156734): We need to stop casting and use HAL types when possible.
    getBE().mRenderEngine =
            renderengine::RenderEngine::create(static_cast<int32_t>(defaultCompositionPixelFormat),
                                               renderEngineFeature);
    LOG_ALWAYS_FATAL_IF(getBE().mRenderEngine == nullptr, "couldn't create RenderEngine");

    LOG_ALWAYS_FATAL_IF(mVrFlingerRequestsDisplay,
            "Starting with vr flinger active is not currently supported.");
    getBE().mHwc = getFactory().createHWComposer(getBE().mHwcServiceName);
    getBE().mHwc->registerCallback(this, getBE().mComposerSequenceId);
    // Process any initial hotplug and resulting display changes.
    processDisplayHotplugEventsLocked();
    const auto display = getDefaultDisplayDeviceLocked();
    LOG_ALWAYS_FATAL_IF(!display, "Missing internal display after registering composer callback.");
    LOG_ALWAYS_FATAL_IF(!getHwComposer().isConnected(*display->getId()),
                        "Internal display is disconnected.");

    if (useVrFlinger) {
        auto vrFlingerRequestDisplayCallback = [this](bool requestDisplay) {
            // This callback is called from the vr flinger dispatch thread. We
            // need to call signalTransaction(), which requires holding
            // mStateLock when we're not on the main thread. Acquiring
            // mStateLock from the vr flinger dispatch thread might trigger a
            // deadlock in surface flinger (see b/66916578), so post a message
            // to be handled on the main thread instead.
            postMessageAsync(new LambdaMessage([=] {
                ALOGI("VR request display mode: requestDisplay=%d", requestDisplay);
                mVrFlingerRequestsDisplay = requestDisplay;
                signalTransaction();
            }));
        };
        mVrFlinger = dvr::VrFlinger::Create(getHwComposer().getComposer(),
                                            getHwComposer()
                                                    .fromPhysicalDisplayId(*display->getId())
                                                    .value_or(0),
                                            vrFlingerRequestDisplayCallback);
        if (!mVrFlinger) {
            ALOGE("Failed to start vrflinger");
        }
    }

    mEventControlThread = getFactory().createEventControlThread(
            [this](bool enabled) { setVsyncEnabled(EventThread::DisplayType::Primary, enabled); });

    // initialize our drawing state
    mDrawingState = mCurrentState;

    // set initial conditions (e.g. unblank default device)
    initializeDisplays();

    getBE().mRenderEngine->primeCache();

    // Inform native graphics APIs whether the present timestamp is supported:

    const bool presentFenceReliable =
            !getHwComposer().hasCapability(HWC2::Capability::PresentFenceIsNotReliable);
    mStartPropertySetThread = getFactory().createStartPropertySetThread(presentFenceReliable);

    if (mStartPropertySetThread->Start() != NO_ERROR) {
        ALOGE("Run StartPropertySetThread failed!");
    }

    // This is a hack. Per definition of getDataspaceSaturationMatrix, the returned matrix
    // is used to saturate legacy sRGB content. However, to make sure the same color under
    // Display P3 will be saturated to the same color, we intentionally break the API spec
    // and apply this saturation matrix on Display P3 content. Unless the risk of applying
    // such saturation matrix on Display P3 is understood fully, the API should always return
    // identify matrix.
    mEnhancedSaturationMatrix =
            getHwComposer().getDataspaceSaturationMatrix(*display->getId(), Dataspace::SRGB_LINEAR);

    // we will apply this on Display P3.
    if (mEnhancedSaturationMatrix != mat4()) {
        ColorSpace srgb(ColorSpace::sRGB());
        ColorSpace displayP3(ColorSpace::DisplayP3());
        mat4 srgbToP3 = mat4(ColorSpaceConnector(srgb, displayP3).getTransform());
        mat4 p3ToSrgb = mat4(ColorSpaceConnector(displayP3, srgb).getTransform());
        mEnhancedSaturationMatrix = srgbToP3 * mEnhancedSaturationMatrix * p3ToSrgb;
    }

    ALOGV("Done initializing");
}

void SurfaceFlinger::readPersistentProperties() {
    Mutex::Autolock _l(mStateLock);

    char value[PROPERTY_VALUE_MAX];

    property_get("persist.sys.sf.color_saturation", value, "1.0");
    mGlobalSaturationFactor = atof(value);
    updateColorMatrixLocked();
    ALOGV("Saturation is set to %.2f", mGlobalSaturationFactor);

    property_get("persist.sys.sf.native_mode", value, "0");
    mDisplayColorSetting = static_cast<DisplayColorSetting>(atoi(value));
}

void SurfaceFlinger::startBootAnim() {
    // Start boot animation service by setting a property mailbox
    // if property setting thread is already running, Start() will be just a NOP
    mStartPropertySetThread->Start();
    // Wait until property was set
    if (mStartPropertySetThread->join() != NO_ERROR) {
        ALOGE("Join StartPropertySetThread failed!");
    }
}

size_t SurfaceFlinger::getMaxTextureSize() const {
    return getBE().mRenderEngine->getMaxTextureSize();
}

size_t SurfaceFlinger::getMaxViewportDims() const {
    return getBE().mRenderEngine->getMaxViewportDims();
}

// ----------------------------------------------------------------------------

bool SurfaceFlinger::authenticateSurfaceTexture(
        const sp<IGraphicBufferProducer>& bufferProducer) const {
    Mutex::Autolock _l(mStateLock);
    return authenticateSurfaceTextureLocked(bufferProducer);
}

bool SurfaceFlinger::authenticateSurfaceTextureLocked(
        const sp<IGraphicBufferProducer>& bufferProducer) const {
    sp<IBinder> surfaceTextureBinder(IInterface::asBinder(bufferProducer));
    return mGraphicBufferProducerList.count(surfaceTextureBinder.get()) > 0;
}

status_t SurfaceFlinger::getSupportedFrameTimestamps(
        std::vector<FrameEvent>* outSupported) const {
    *outSupported = {
        FrameEvent::REQUESTED_PRESENT,
        FrameEvent::ACQUIRE,
        FrameEvent::LATCH,
        FrameEvent::FIRST_REFRESH_START,
        FrameEvent::LAST_REFRESH_START,
        FrameEvent::GPU_COMPOSITION_DONE,
        FrameEvent::DEQUEUE_READY,
        FrameEvent::RELEASE,
    };
    ConditionalLock _l(mStateLock,
            std::this_thread::get_id() != mMainThreadId);
    if (!getHwComposer().hasCapability(
            HWC2::Capability::PresentFenceIsNotReliable)) {
        outSupported->push_back(FrameEvent::DISPLAY_PRESENT);
    }
    return NO_ERROR;
}

status_t SurfaceFlinger::getDisplayConfigs(const sp<IBinder>& displayToken,
                                           Vector<DisplayInfo>* configs) {
    if (!displayToken || !configs) {
        return BAD_VALUE;
    }

    const auto displayId = getPhysicalDisplayId(displayToken);
    if (!displayId) {
        return NAME_NOT_FOUND;
    }

    // TODO: Not sure if display density should handled by SF any longer
    class Density {
        static float getDensityFromProperty(char const* propName) {
            char property[PROPERTY_VALUE_MAX];
            float density = 0.0f;
            if (property_get(propName, property, nullptr) > 0) {
                density = strtof(property, nullptr);
            }
            return density;
        }
    public:
        static float getEmuDensity() {
            return getDensityFromProperty("qemu.sf.lcd_density"); }
        static float getBuildDensity()  {
            return getDensityFromProperty("ro.sf.lcd_density"); }
    };

    configs->clear();

    ConditionalLock _l(mStateLock,
            std::this_thread::get_id() != mMainThreadId);
    for (const auto& hwConfig : getHwComposer().getConfigs(*displayId)) {
        DisplayInfo info = DisplayInfo();

        float xdpi = hwConfig->getDpiX();
        float ydpi = hwConfig->getDpiY();

        info.w = hwConfig->getWidth();
        info.h = hwConfig->getHeight();
        // Default display viewport to display width and height
        info.viewportW = info.w;
        info.viewportH = info.h;

        if (displayId == getInternalDisplayId()) {
            // The density of the device is provided by a build property
            float density = Density::getBuildDensity() / 160.0f;
            if (density == 0) {
                // the build doesn't provide a density -- this is wrong!
                // use xdpi instead
                ALOGE("ro.sf.lcd_density must be defined as a build property");
                density = xdpi / 160.0f;
            }
            if (Density::getEmuDensity()) {
                // if "qemu.sf.lcd_density" is specified, it overrides everything
                xdpi = ydpi = density = Density::getEmuDensity();
                density /= 160.0f;
            }
            info.density = density;

            // TODO: this needs to go away (currently needed only by webkit)
            const auto display = getDefaultDisplayDeviceLocked();
            info.orientation = display ? display->getOrientation() : 0;

            // This is for screenrecord
            const Rect viewport = display->getViewport();
            if (viewport.isValid()) {
                info.viewportW = uint32_t(viewport.getWidth());
                info.viewportH = uint32_t(viewport.getHeight());
            }
        } else {
            // TODO: where should this value come from?
            static const int TV_DENSITY = 213;
            info.density = TV_DENSITY / 160.0f;
            info.orientation = 0;
        }

        info.xdpi = xdpi;
        info.ydpi = ydpi;
        info.fps = 1e9 / hwConfig->getVsyncPeriod();
        info.appVsyncOffset = vsyncPhaseOffsetNs;

        // This is how far in advance a buffer must be queued for
        // presentation at a given time.  If you want a buffer to appear
        // on the screen at time N, you must submit the buffer before
        // (N - presentationDeadline).
        //
        // Normally it's one full refresh period (to give SF a chance to
        // latch the buffer), but this can be reduced by configuring a
        // DispSync offset.  Any additional delays introduced by the hardware
        // composer or panel must be accounted for here.
        //
        // We add an additional 1ms to allow for processing time and
        // differences between the ideal and actual refresh rate.
        info.presentationDeadline = hwConfig->getVsyncPeriod() -
                sfVsyncPhaseOffsetNs + 1000000;

        // All non-virtual displays are currently considered secure.
        info.secure = true;

        if (displayId == getInternalDisplayId() &&
            primaryDisplayOrientation & DisplayState::eOrientationSwapMask) {
            std::swap(info.w, info.h);
        }

        configs->push_back(info);
    }

    return NO_ERROR;
}

status_t SurfaceFlinger::getDisplayStats(const sp<IBinder>&, DisplayStatInfo* stats) {
    if (!stats) {
        return BAD_VALUE;
    }

    if (mUseScheduler) {
        mScheduler->getDisplayStatInfo(stats);
    } else {
        stats->vsyncTime = mPrimaryDispSync->computeNextRefresh(0);
        stats->vsyncPeriod = mPrimaryDispSync->getPeriod();
    }
    return NO_ERROR;
}

int SurfaceFlinger::getActiveConfig(const sp<IBinder>& displayToken) {
    const auto display = getDisplayDevice(displayToken);
    if (!display) {
        ALOGE("getActiveConfig: Invalid display token %p", displayToken.get());
        return BAD_VALUE;
    }

    return display->getActiveConfig();
}

void SurfaceFlinger::setActiveConfigInternal(const sp<DisplayDevice>& display, int mode) {
    if (display->isVirtual()) {
        ALOGE("%s: Invalid operation on virtual display", __FUNCTION__);
        return;
    }

    int currentMode = display->getActiveConfig();
    if (mode == currentMode) {
        return;
    }

    const auto displayId = display->getId();
    LOG_ALWAYS_FATAL_IF(!displayId);

    display->setActiveConfig(mode);
    getHwComposer().setActiveConfig(*displayId, mode);
}

status_t SurfaceFlinger::setActiveConfig(const sp<IBinder>& displayToken, int mode) {
    postMessageSync(new LambdaMessage([&] {
        Vector<DisplayInfo> configs;
        getDisplayConfigs(displayToken, &configs);
        if (mode < 0 || mode >= static_cast<int>(configs.size())) {
            ALOGE("Attempt to set active config %d for display with %zu configs", mode,
                  configs.size());
            return;
        }
        const auto display = getDisplayDevice(displayToken);
        if (!display) {
            ALOGE("Attempt to set active config %d for invalid display token %p", mode,
                  displayToken.get());
        } else if (display->isVirtual()) {
            ALOGW("Attempt to set active config %d for virtual display", mode);
        } else {
            setActiveConfigInternal(display, mode);
        }
    }));

    return NO_ERROR;
}

status_t SurfaceFlinger::getDisplayColorModes(const sp<IBinder>& displayToken,
                                              Vector<ColorMode>* outColorModes) {
    if (!displayToken || !outColorModes) {
        return BAD_VALUE;
    }

    const auto displayId = getPhysicalDisplayId(displayToken);
    if (!displayId) {
        return NAME_NOT_FOUND;
    }

    std::vector<ColorMode> modes;
    {
        ConditionalLock _l(mStateLock,
                std::this_thread::get_id() != mMainThreadId);
        modes = getHwComposer().getColorModes(*displayId);
    }
    outColorModes->clear();
    std::copy(modes.cbegin(), modes.cend(), std::back_inserter(*outColorModes));

    return NO_ERROR;
}

ColorMode SurfaceFlinger::getActiveColorMode(const sp<IBinder>& displayToken) {
    if (const auto display = getDisplayDevice(displayToken)) {
        return display->getActiveColorMode();
    }
    return static_cast<ColorMode>(BAD_VALUE);
}

void SurfaceFlinger::setActiveColorModeInternal(const sp<DisplayDevice>& display, ColorMode mode,
                                                Dataspace dataSpace, RenderIntent renderIntent) {
    if (display->isVirtual()) {
        ALOGE("%s: Invalid operation on virtual display", __FUNCTION__);
        return;
    }

    ColorMode currentMode = display->getActiveColorMode();
    Dataspace currentDataSpace = display->getCompositionDataSpace();
    RenderIntent currentRenderIntent = display->getActiveRenderIntent();

    if (mode == currentMode && dataSpace == currentDataSpace &&
        renderIntent == currentRenderIntent) {
        return;
    }

    display->setActiveColorMode(mode);
    display->setCompositionDataSpace(dataSpace);
    display->setActiveRenderIntent(renderIntent);

    const auto displayId = display->getId();
    LOG_ALWAYS_FATAL_IF(!displayId);
    getHwComposer().setActiveColorMode(*displayId, mode, renderIntent);

    ALOGV("Set active color mode: %s (%d), active render intent: %s (%d), display=%s",
          decodeColorMode(mode).c_str(), mode, decodeRenderIntent(renderIntent).c_str(),
          renderIntent, to_string(*displayId).c_str());
}

status_t SurfaceFlinger::setActiveColorMode(const sp<IBinder>& displayToken, ColorMode mode) {
    postMessageSync(new LambdaMessage([&] {
        Vector<ColorMode> modes;
        getDisplayColorModes(displayToken, &modes);
        bool exists = std::find(std::begin(modes), std::end(modes), mode) != std::end(modes);
        if (mode < ColorMode::NATIVE || !exists) {
            ALOGE("Attempt to set invalid active color mode %s (%d) for display token %p",
                  decodeColorMode(mode).c_str(), mode, displayToken.get());
            return;
        }
        const auto display = getDisplayDevice(displayToken);
        if (!display) {
            ALOGE("Attempt to set active color mode %s (%d) for invalid display token %p",
                  decodeColorMode(mode).c_str(), mode, displayToken.get());
        } else if (display->isVirtual()) {
            ALOGW("Attempt to set active color mode %s (%d) for virtual display",
                  decodeColorMode(mode).c_str(), mode);
        } else {
            setActiveColorModeInternal(display, mode, Dataspace::UNKNOWN,
                                       RenderIntent::COLORIMETRIC);
        }
    }));

    return NO_ERROR;
}

status_t SurfaceFlinger::clearAnimationFrameStats() {
    Mutex::Autolock _l(mStateLock);
    mAnimFrameTracker.clearStats();
    return NO_ERROR;
}

status_t SurfaceFlinger::getAnimationFrameStats(FrameStats* outStats) const {
    Mutex::Autolock _l(mStateLock);
    mAnimFrameTracker.getStats(outStats);
    return NO_ERROR;
}

status_t SurfaceFlinger::getHdrCapabilities(const sp<IBinder>& displayToken,
                                            HdrCapabilities* outCapabilities) const {
    Mutex::Autolock _l(mStateLock);

    const auto display = getDisplayDeviceLocked(displayToken);
    if (!display) {
        ALOGE("getHdrCapabilities: Invalid display token %p", displayToken.get());
        return BAD_VALUE;
    }

    // At this point the DisplayDeivce should already be set up,
    // meaning the luminance information is already queried from
    // hardware composer and stored properly.
    const HdrCapabilities& capabilities = display->getHdrCapabilities();
    *outCapabilities = HdrCapabilities(capabilities.getSupportedHdrTypes(),
                                       capabilities.getDesiredMaxLuminance(),
                                       capabilities.getDesiredMaxAverageLuminance(),
                                       capabilities.getDesiredMinLuminance());

    return NO_ERROR;
}

status_t SurfaceFlinger::enableVSyncInjections(bool enable) {
    postMessageSync(new LambdaMessage([&] {
        Mutex::Autolock _l(mStateLock);

        if (mInjectVSyncs == enable) {
            return;
        }

        // TODO(akrulec): Part of the Injector should be refactored, so that it
        // can be passed to Scheduler.
        if (enable) {
            ALOGV("VSync Injections enabled");
            if (mVSyncInjector.get() == nullptr) {
                mVSyncInjector = std::make_unique<InjectVSyncSource>();
                mInjectorEventThread = std::make_unique<
                        impl::EventThread>(mVSyncInjector.get(), [this] { resyncWithRateLimit(); },
                                           impl::EventThread::InterceptVSyncsCallback(),
                                           "injEventThread");
            }
            mEventQueue->setEventThread(mInjectorEventThread.get());
        } else {
            ALOGV("VSync Injections disabled");
            mEventQueue->setEventThread(mSFEventThread.get());
        }

        mInjectVSyncs = enable;
    }));

    return NO_ERROR;
}

status_t SurfaceFlinger::injectVSync(nsecs_t when) {
    Mutex::Autolock _l(mStateLock);

    if (!mInjectVSyncs) {
        ALOGE("VSync Injections not enabled");
        return BAD_VALUE;
    }
    if (mInjectVSyncs && mInjectorEventThread.get() != nullptr) {
        ALOGV("Injecting VSync inside SurfaceFlinger");
        mVSyncInjector->onInjectSyncEvent(when);
    }
    return NO_ERROR;
}

status_t SurfaceFlinger::getLayerDebugInfo(std::vector<LayerDebugInfo>* outLayers) const
        NO_THREAD_SAFETY_ANALYSIS {
    // Try to acquire a lock for 1s, fail gracefully
    const status_t err = mStateLock.timedLock(s2ns(1));
    const bool locked = (err == NO_ERROR);
    if (!locked) {
        ALOGE("LayerDebugInfo: SurfaceFlinger unresponsive (%s [%d]) - exit", strerror(-err), err);
        return TIMED_OUT;
    }

    outLayers->clear();
    mCurrentState.traverseInZOrder([&](Layer* layer) {
        outLayers->push_back(layer->getLayerDebugInfo());
    });

    mStateLock.unlock();
    return NO_ERROR;
}

status_t SurfaceFlinger::getCompositionPreference(
        Dataspace* outDataspace, ui::PixelFormat* outPixelFormat,
        Dataspace* outWideColorGamutDataspace,
        ui::PixelFormat* outWideColorGamutPixelFormat) const {
    *outDataspace = mDefaultCompositionDataspace;
    *outPixelFormat = defaultCompositionPixelFormat;
    *outWideColorGamutDataspace = mWideColorGamutCompositionDataspace;
    *outWideColorGamutPixelFormat = wideColorGamutCompositionPixelFormat;
    return NO_ERROR;
}

// ----------------------------------------------------------------------------

sp<IDisplayEventConnection> SurfaceFlinger::createDisplayEventConnection(
        ISurfaceComposer::VsyncSource vsyncSource) {
    if (mUseScheduler) {
        if (vsyncSource == eVsyncSourceSurfaceFlinger) {
            return mScheduler->createDisplayEventConnection(mSfConnectionHandle);
        } else {
            return mScheduler->createDisplayEventConnection(mAppConnectionHandle);
        }
    } else {
        if (vsyncSource == eVsyncSourceSurfaceFlinger) {
            return mSFEventThread->createEventConnection();
        } else {
            return mEventThread->createEventConnection();
        }
    }
}

// ----------------------------------------------------------------------------

void SurfaceFlinger::waitForEvent() {
    mEventQueue->waitMessage();
}

void SurfaceFlinger::signalTransaction() {
    mEventQueue->invalidate();
}

void SurfaceFlinger::signalLayerUpdate() {
    mEventQueue->invalidate();
}

void SurfaceFlinger::signalRefresh() {
    mRefreshPending = true;
    mEventQueue->refresh();
}

status_t SurfaceFlinger::postMessageAsync(const sp<MessageBase>& msg,
        nsecs_t reltime, uint32_t /* flags */) {
    return mEventQueue->postMessage(msg, reltime);
}

status_t SurfaceFlinger::postMessageSync(const sp<MessageBase>& msg,
        nsecs_t reltime, uint32_t /* flags */) {
    status_t res = mEventQueue->postMessage(msg, reltime);
    if (res == NO_ERROR) {
        msg->wait();
    }
    return res;
}

void SurfaceFlinger::run() {
    do {
        waitForEvent();
    } while (true);
}

void SurfaceFlinger::enableHardwareVsync() {
    Mutex::Autolock _l(mHWVsyncLock);
    if (!mPrimaryHWVsyncEnabled && mHWVsyncAvailable) {
        mPrimaryDispSync->beginResync();
        mEventControlThread->setVsyncEnabled(true);
        mPrimaryHWVsyncEnabled = true;
    }
}

void SurfaceFlinger::resyncToHardwareVsync(bool makeAvailable) {
    Mutex::Autolock _l(mHWVsyncLock);

    if (makeAvailable) {
        mHWVsyncAvailable = true;
        // TODO(b/113612090): This is silly, but necessary evil until we turn on the flag for good.
        if (mUseScheduler) {
            mScheduler->makeHWSyncAvailable(true);
        }
    } else if (!mHWVsyncAvailable) {
        // Hardware vsync is not currently available, so abort the resync
        // attempt for now
        return;
    }

    const auto displayId = getInternalDisplayId();
    if (!displayId || !getHwComposer().isConnected(*displayId)) {
        return;
    }

    const auto activeConfig = getHwComposer().getActiveConfig(*displayId);
    const nsecs_t period = activeConfig->getVsyncPeriod();

    if (mUseScheduler) {
        mScheduler->setVsyncPeriod(period);
    } else {
        mPrimaryDispSync->reset();
        mPrimaryDispSync->setPeriod(period);

        if (!mPrimaryHWVsyncEnabled) {
            mPrimaryDispSync->beginResync();
            mEventControlThread->setVsyncEnabled(true);
            mPrimaryHWVsyncEnabled = true;
        }
    }
}

void SurfaceFlinger::disableHardwareVsync(bool makeUnavailable) {
    Mutex::Autolock _l(mHWVsyncLock);
    if (mPrimaryHWVsyncEnabled) {
        mEventControlThread->setVsyncEnabled(false);
        mPrimaryDispSync->endResync();
        mPrimaryHWVsyncEnabled = false;
    }
    if (makeUnavailable) {
        mHWVsyncAvailable = false;
    }
}

void SurfaceFlinger::resyncWithRateLimit() {
    static constexpr nsecs_t kIgnoreDelay = ms2ns(500);

    // No explicit locking is needed here since EventThread holds a lock while calling this method
    static nsecs_t sLastResyncAttempted = 0;
    const nsecs_t now = systemTime();
    if (now - sLastResyncAttempted > kIgnoreDelay) {
        resyncToHardwareVsync(false);
    }
    sLastResyncAttempted = now;
}

void SurfaceFlinger::onVsyncReceived(int32_t sequenceId, hwc2_display_t hwcDisplayId,
                                     int64_t timestamp) {
    ATRACE_NAME("SF onVsync");

    Mutex::Autolock lock(mStateLock);
    // Ignore any vsyncs from a previous hardware composer.
    if (sequenceId != getBE().mComposerSequenceId) {
        return;
    }

    if (!getHwComposer().onVsync(hwcDisplayId, timestamp)) {
        return;
    }

    if (hwcDisplayId != getHwComposer().getInternalHwcDisplayId()) {
        // For now, we don't do anything with external display vsyncs.
        return;
    }

    if (mUseScheduler) {
        mScheduler->addResyncSample(timestamp);
    } else {
        bool needsHwVsync = false;
        { // Scope for the lock
            Mutex::Autolock _l(mHWVsyncLock);
            if (mPrimaryHWVsyncEnabled) {
                needsHwVsync = mPrimaryDispSync->addResyncSample(timestamp);
            }
        }

        if (needsHwVsync) {
            enableHardwareVsync();
        } else {
            disableHardwareVsync(false);
        }
    }
}

void SurfaceFlinger::getCompositorTiming(CompositorTiming* compositorTiming) {
    std::lock_guard<std::mutex> lock(getBE().mCompositorTimingLock);
    *compositorTiming = getBE().mCompositorTiming;
}

void SurfaceFlinger::onHotplugReceived(int32_t sequenceId, hwc2_display_t hwcDisplayId,
                                       HWC2::Connection connection) {
    ALOGV("%s(%d, %" PRIu64 ", %s)", __FUNCTION__, sequenceId, hwcDisplayId,
          connection == HWC2::Connection::Connected ? "connected" : "disconnected");

    // Ignore events that do not have the right sequenceId.
    if (sequenceId != getBE().mComposerSequenceId) {
        return;
    }

    // Only lock if we're not on the main thread. This function is normally
    // called on a hwbinder thread, but for the primary display it's called on
    // the main thread with the state lock already held, so don't attempt to
    // acquire it here.
    ConditionalLock lock(mStateLock, std::this_thread::get_id() != mMainThreadId);

    mPendingHotplugEvents.emplace_back(HotplugEvent{hwcDisplayId, connection});

    if (std::this_thread::get_id() == mMainThreadId) {
        // Process all pending hot plug events immediately if we are on the main thread.
        processDisplayHotplugEventsLocked();
    }

    setTransactionFlags(eDisplayTransactionNeeded);
}

void SurfaceFlinger::onRefreshReceived(int sequenceId, hwc2_display_t /*hwcDisplayId*/) {
    Mutex::Autolock lock(mStateLock);
    if (sequenceId != getBE().mComposerSequenceId) {
        return;
    }
    repaintEverything();
}

void SurfaceFlinger::setVsyncEnabled(EventThread::DisplayType /*displayType*/, bool enabled) {
    ATRACE_CALL();
    Mutex::Autolock lock(mStateLock);
    if (const auto displayId = getInternalDisplayId()) {
        getHwComposer().setVsyncEnabled(*displayId,
                                        enabled ? HWC2::Vsync::Enable : HWC2::Vsync::Disable);
    }
}

// Note: it is assumed the caller holds |mStateLock| when this is called
void SurfaceFlinger::resetDisplayState() {
    if (mUseScheduler) {
        mScheduler->disableHardwareVsync(true);
    } else {
        disableHardwareVsync(true);
    }
    // Clear the drawing state so that the logic inside of
    // handleTransactionLocked will fire. It will determine the delta between
    // mCurrentState and mDrawingState and re-apply all changes when we make the
    // transition.
    mDrawingState.displays.clear();
    mDisplays.clear();
}

void SurfaceFlinger::updateVrFlinger() {
    if (!mVrFlinger)
        return;
    bool vrFlingerRequestsDisplay = mVrFlingerRequestsDisplay;
    if (vrFlingerRequestsDisplay == getBE().mHwc->isUsingVrComposer()) {
        return;
    }

    if (vrFlingerRequestsDisplay && !getBE().mHwc->getComposer()->isRemote()) {
        ALOGE("Vr flinger is only supported for remote hardware composer"
              " service connections. Ignoring request to transition to vr"
              " flinger.");
        mVrFlingerRequestsDisplay = false;
        return;
    }

    Mutex::Autolock _l(mStateLock);

    sp<DisplayDevice> display = getDefaultDisplayDeviceLocked();
    LOG_ALWAYS_FATAL_IF(!display);
    const int currentDisplayPowerMode = display->getPowerMode();
    // This DisplayDevice will no longer be relevant once resetDisplayState() is
    // called below. Clear the reference now so we don't accidentally use it
    // later.
    display.clear();

    if (!vrFlingerRequestsDisplay) {
        mVrFlinger->SeizeDisplayOwnership();
    }

    resetDisplayState();
    getBE().mHwc.reset(); // Delete the current instance before creating the new one
    getBE().mHwc = getFactory().createHWComposer(
            vrFlingerRequestsDisplay ? "vr" : getBE().mHwcServiceName);
    getBE().mHwc->registerCallback(this, ++getBE().mComposerSequenceId);

    LOG_ALWAYS_FATAL_IF(!getBE().mHwc->getComposer()->isRemote(),
                        "Switched to non-remote hardware composer");

    if (vrFlingerRequestsDisplay) {
        mVrFlinger->GrantDisplayOwnership();
    }

    mVisibleRegionsDirty = true;
    invalidateHwcGeometry();

    // Re-enable default display.
    display = getDefaultDisplayDeviceLocked();
    LOG_ALWAYS_FATAL_IF(!display);
    setPowerModeInternal(display, currentDisplayPowerMode, /*stateLockHeld*/ true);

    // Reset the timing values to account for the period of the swapped in HWC
    const auto activeConfig = getHwComposer().getActiveConfig(*display->getId());
    const nsecs_t period = activeConfig->getVsyncPeriod();
    mAnimFrameTracker.setDisplayRefreshPeriod(period);

    // The present fences returned from vr_hwc are not an accurate
    // representation of vsync times.
    if (mUseScheduler) {
        mScheduler->setIgnorePresentFences(getBE().mHwc->isUsingVrComposer() || !hasSyncFramework);
    } else {
        mPrimaryDispSync->setIgnorePresentFences(getBE().mHwc->isUsingVrComposer() ||
                                                 !hasSyncFramework);
    }

    // Use phase of 0 since phase is not known.
    // Use latency of 0, which will snap to the ideal latency.
    DisplayStatInfo stats{0 /* vsyncTime */, period /* vsyncPeriod */};
    setCompositorTimingSnapped(stats, 0);

    resyncToHardwareVsync(false);

    mRepaintEverything = true;
    setTransactionFlags(eDisplayTransactionNeeded);
}

void SurfaceFlinger::onMessageReceived(int32_t what) {
    ATRACE_CALL();
    switch (what) {
        case MessageQueue::INVALIDATE: {
            bool frameMissed = !mHadClientComposition &&
                    mPreviousPresentFence != Fence::NO_FENCE &&
                    (mPreviousPresentFence->getSignalTime() ==
                            Fence::SIGNAL_TIME_PENDING);
            mFrameMissedCount += frameMissed;
            ATRACE_INT("FrameMissed", static_cast<int>(frameMissed));
            if (frameMissed) {
                mTimeStats.incrementMissedFrames();
                if (mPropagateBackpressure) {
                    signalLayerUpdate();
                    break;
                }
            }

            // Now that we're going to make it to the handleMessageTransaction()
            // call below it's safe to call updateVrFlinger(), which will
            // potentially trigger a display handoff.
            updateVrFlinger();

            bool refreshNeeded = handleMessageTransaction();
            refreshNeeded |= handleMessageInvalidate();
            refreshNeeded |= mRepaintEverything;
            if (refreshNeeded && CC_LIKELY(mBootStage != BootStage::BOOTLOADER)) {
                // Signal a refresh if a transaction modified the window state,
                // a new buffer was latched, or if HWC has requested a full
                // repaint
                signalRefresh();
            }
            break;
        }
        case MessageQueue::REFRESH: {
            handleMessageRefresh();
            break;
        }
    }
}

bool SurfaceFlinger::handleMessageTransaction() {
    uint32_t transactionFlags = peekTransactionFlags();
    if (transactionFlags) {
        handleTransaction(transactionFlags);
        return true;
    }
    return false;
}

void SurfaceFlinger::handleMessageRefresh() {
    ATRACE_CALL();

    mRefreshPending = false;

    const bool repaintEverything = mRepaintEverything.exchange(false);
    preComposition();
    rebuildLayerStacks();
    calculateWorkingSet();
    for (const auto& [token, display] : mDisplays) {
        beginFrame(display);
        prepareFrame(display);
        doDebugFlashRegions(display, repaintEverything);
        doComposition(display, repaintEverything);
    }

    doTracing("handleRefresh");
    logLayerStats();

    postFrame();
    postComposition();

    mHadClientComposition = false;
    for (const auto& [token, display] : mDisplays) {
        mHadClientComposition = mHadClientComposition ||
                getBE().mHwc->hasClientComposition(display->getId());
    }

    // Setup RenderEngine sync fences if native sync is supported.
    if (getBE().mRenderEngine->useNativeFenceSync()) {
        if (mHadClientComposition) {
            base::unique_fd flushFence(getRenderEngine().flush());
            ALOGE_IF(flushFence < 0, "Failed to flush RenderEngine!");
            getBE().flushFence = new Fence(std::move(flushFence));
        } else {
            // Cleanup for hygiene.
            getBE().flushFence = Fence::NO_FENCE;
        }
    }

    mVsyncModulator.onRefreshed(mHadClientComposition);

    getBE().mEndOfFrameCompositionInfo = std::move(getBE().mCompositionInfo);
    for (const auto& [token, display] : mDisplays) {
        for (auto& compositionInfo : getBE().mEndOfFrameCompositionInfo[token]) {
            compositionInfo.hwc.hwcLayer = nullptr;
        }
    }

    mLayersWithQueuedFrames.clear();
}


bool SurfaceFlinger::handleMessageInvalidate() {
    ATRACE_CALL();
    return handlePageFlip();
}

void SurfaceFlinger::calculateWorkingSet() {
    ATRACE_CALL();
    ALOGV(__FUNCTION__);

    // build the h/w work list
    if (CC_UNLIKELY(mGeometryInvalid)) {
        mGeometryInvalid = false;
        for (const auto& [token, display] : mDisplays) {
            const auto displayId = display->getId();
            if (!displayId) {
                continue;
            }

            const Vector<sp<Layer>>& currentLayers = display->getVisibleLayersSortedByZ();
            for (size_t i = 0; i < currentLayers.size(); i++) {
                const auto& layer = currentLayers[i];

                if (!layer->hasHwcLayer(*displayId)) {
                    if (!layer->createHwcLayer(&getHwComposer(), *displayId)) {
                        layer->forceClientComposition(*displayId);
                        continue;
                    }
                }

                layer->setGeometry(display, i);
                if (mDebugDisableHWC || mDebugRegion) {
                    layer->forceClientComposition(*displayId);
                }
            }
        }
    }

    // Set the per-frame data
    for (const auto& [token, display] : mDisplays) {
        const auto displayId = display->getId();
        if (!displayId) {
            continue;
        }

        if (mDrawingState.colorMatrixChanged) {
            display->setColorTransform(mDrawingState.colorMatrix);
            status_t result =
                    getHwComposer().setColorTransform(*displayId, mDrawingState.colorMatrix);
            ALOGE_IF(result != NO_ERROR, "Failed to set color transform on display %s: %d",
                     to_string(*displayId).c_str(), result);
        }
        for (auto& layer : display->getVisibleLayersSortedByZ()) {
            if (layer->isHdrY410()) {
                layer->forceClientComposition(*displayId);
            } else if ((layer->getDataSpace() == Dataspace::BT2020_PQ ||
                        layer->getDataSpace() == Dataspace::BT2020_ITU_PQ) &&
                    !display->hasHDR10Support()) {
                layer->forceClientComposition(*displayId);
            } else if ((layer->getDataSpace() == Dataspace::BT2020_HLG ||
                        layer->getDataSpace() == Dataspace::BT2020_ITU_HLG) &&
                    !display->hasHLGSupport()) {
                layer->forceClientComposition(*displayId);
            }

            // TODO(b/111562338) remove when composer 2.3 is shipped.
            if (layer->hasColorTransform()) {
                layer->forceClientComposition(*displayId);
            }

            if (layer->getForceClientComposition(*displayId)) {
                ALOGV("[%s] Requesting Client composition", layer->getName().string());
                layer->setCompositionType(*displayId, HWC2::Composition::Client);
                continue;
            }

            layer->setPerFrameData(*displayId, display->getTransform(), display->getViewport(),
                                   display->getSupportedPerFrameMetadata());
        }

        if (useColorManagement) {
            ColorMode  colorMode;
            Dataspace dataSpace;
            RenderIntent renderIntent;
            pickColorMode(display, &colorMode, &dataSpace, &renderIntent);
            setActiveColorModeInternal(display, colorMode, dataSpace, renderIntent);
        }
    }

    mDrawingState.colorMatrixChanged = false;

    for (const auto& [token, display] : mDisplays) {
        for (auto& layer : display->getVisibleLayersSortedByZ()) {
            const auto displayId = display->getId();
            layer->getBE().compositionInfo.compositionType = layer->getCompositionType(displayId);

            if (displayId) {
                if (!layer->setHwcLayer(*displayId)) {
                    ALOGV("Need to create HWCLayer for %s", layer->getName().string());
                }
                layer->getBE().compositionInfo.hwc.displayId = *displayId;
            }

            getBE().mCompositionInfo[token].push_back(layer->getBE().compositionInfo);
            layer->getBE().compositionInfo.hwc.hwcLayer = nullptr;
        }
    }
}

void SurfaceFlinger::doDebugFlashRegions(const sp<DisplayDevice>& display, bool repaintEverything)
{
    // is debugging enabled
    if (CC_LIKELY(!mDebugRegion))
        return;

    if (display->isPoweredOn()) {
        // transform the dirty region into this screen's coordinate space
        const Region dirtyRegion(display->getDirtyRegion(repaintEverything));
        if (!dirtyRegion.isEmpty()) {
            // redraw the whole screen
            doComposeSurfaces(display);

            // and draw the dirty region
            auto& engine(getRenderEngine());
            engine.fillRegionWithColor(dirtyRegion, 1, 0, 1, 1);

            display->queueBuffer(getHwComposer());
        }
    }

    postFramebuffer(display);

    if (mDebugRegion > 1) {
        usleep(mDebugRegion * 1000);
    }

    prepareFrame(display);
}

void SurfaceFlinger::doTracing(const char* where) {
    ATRACE_CALL();
    ATRACE_NAME(where);
    if (CC_UNLIKELY(mTracing.isEnabled())) {
        mTracing.traceLayers(where, dumpProtoInfo(LayerVector::StateSet::Drawing));
    }
}

void SurfaceFlinger::logLayerStats() {
    ATRACE_CALL();
    if (CC_UNLIKELY(mLayerStats.isEnabled())) {
        for (const auto& [token, display] : mDisplays) {
            if (display->isPrimary()) {
                mLayerStats.logLayerStats(dumpVisibleLayersProtoInfo(*display));
                return;
            }
        }

        ALOGE("logLayerStats: no primary display");
    }
}

void SurfaceFlinger::preComposition()
{
    ATRACE_CALL();
    ALOGV("preComposition");

    mRefreshStartTime = systemTime(SYSTEM_TIME_MONOTONIC);

    bool needExtraInvalidate = false;
    mDrawingState.traverseInZOrder([&](Layer* layer) {
        if (layer->onPreComposition(mRefreshStartTime)) {
            needExtraInvalidate = true;
        }
    });

    if (needExtraInvalidate) {
        signalLayerUpdate();
    }
}

void SurfaceFlinger::updateCompositorTiming(const DisplayStatInfo& stats, nsecs_t compositeTime,
                                            std::shared_ptr<FenceTime>& presentFenceTime) {
    // Update queue of past composite+present times and determine the
    // most recently known composite to present latency.
    getBE().mCompositePresentTimes.push({compositeTime, presentFenceTime});
    nsecs_t compositeToPresentLatency = -1;
    while (!getBE().mCompositePresentTimes.empty()) {
        SurfaceFlingerBE::CompositePresentTime& cpt = getBE().mCompositePresentTimes.front();
        // Cached values should have been updated before calling this method,
        // which helps avoid duplicate syscalls.
        nsecs_t displayTime = cpt.display->getCachedSignalTime();
        if (displayTime == Fence::SIGNAL_TIME_PENDING) {
            break;
        }
        compositeToPresentLatency = displayTime - cpt.composite;
        getBE().mCompositePresentTimes.pop();
    }

    // Don't let mCompositePresentTimes grow unbounded, just in case.
    while (getBE().mCompositePresentTimes.size() > 16) {
        getBE().mCompositePresentTimes.pop();
    }

    setCompositorTimingSnapped(stats, compositeToPresentLatency);
}

void SurfaceFlinger::setCompositorTimingSnapped(const DisplayStatInfo& stats,
                                                nsecs_t compositeToPresentLatency) {
    // Integer division and modulo round toward 0 not -inf, so we need to
    // treat negative and positive offsets differently.
    nsecs_t idealLatency = (sfVsyncPhaseOffsetNs > 0)
            ? (stats.vsyncPeriod - (sfVsyncPhaseOffsetNs % stats.vsyncPeriod))
            : ((-sfVsyncPhaseOffsetNs) % stats.vsyncPeriod);

    // Just in case sfVsyncPhaseOffsetNs == -vsyncInterval.
    if (idealLatency <= 0) {
        idealLatency = stats.vsyncPeriod;
    }

    // Snap the latency to a value that removes scheduling jitter from the
    // composition and present times, which often have >1ms of jitter.
    // Reducing jitter is important if an app attempts to extrapolate
    // something (such as user input) to an accurate diasplay time.
    // Snapping also allows an app to precisely calculate sfVsyncPhaseOffsetNs
    // with (presentLatency % interval).
    nsecs_t bias = stats.vsyncPeriod / 2;
    int64_t extraVsyncs = (compositeToPresentLatency - idealLatency + bias) / stats.vsyncPeriod;
    nsecs_t snappedCompositeToPresentLatency =
            (extraVsyncs > 0) ? idealLatency + (extraVsyncs * stats.vsyncPeriod) : idealLatency;

    std::lock_guard<std::mutex> lock(getBE().mCompositorTimingLock);
    getBE().mCompositorTiming.deadline = stats.vsyncTime - idealLatency;
    getBE().mCompositorTiming.interval = stats.vsyncPeriod;
    getBE().mCompositorTiming.presentLatency = snappedCompositeToPresentLatency;
}

void SurfaceFlinger::postComposition()
{
    ATRACE_CALL();
    ALOGV("postComposition");

    // Release any buffers which were replaced this frame
    nsecs_t dequeueReadyTime = systemTime();
    for (auto& layer : mLayersWithQueuedFrames) {
        layer->releasePendingBuffer(dequeueReadyTime);
    }

    // |mStateLock| not needed as we are on the main thread
    const auto display = getDefaultDisplayDeviceLocked();

    getBE().mGlCompositionDoneTimeline.updateSignalTimes();
    std::shared_ptr<FenceTime> glCompositionDoneFenceTime;
    if (display && getHwComposer().hasClientComposition(display->getId())) {
        glCompositionDoneFenceTime =
                std::make_shared<FenceTime>(display->getClientTargetAcquireFence());
        getBE().mGlCompositionDoneTimeline.push(glCompositionDoneFenceTime);
    } else {
        glCompositionDoneFenceTime = FenceTime::NO_FENCE;
    }

    getBE().mDisplayTimeline.updateSignalTimes();
    mPreviousPresentFence =
            display ? getHwComposer().getPresentFence(*display->getId()) : Fence::NO_FENCE;
    auto presentFenceTime = std::make_shared<FenceTime>(mPreviousPresentFence);
    getBE().mDisplayTimeline.push(presentFenceTime);

    DisplayStatInfo stats;
    if (mUseScheduler) {
        mScheduler->getDisplayStatInfo(&stats);
    } else {
        stats.vsyncTime = mPrimaryDispSync->computeNextRefresh(0);
        stats.vsyncPeriod = mPrimaryDispSync->getPeriod();
    }

    // We use the mRefreshStartTime which might be sampled a little later than
    // when we started doing work for this frame, but that should be okay
    // since updateCompositorTiming has snapping logic.
    updateCompositorTiming(stats, mRefreshStartTime, presentFenceTime);
    CompositorTiming compositorTiming;
    {
        std::lock_guard<std::mutex> lock(getBE().mCompositorTimingLock);
        compositorTiming = getBE().mCompositorTiming;
    }

    mDrawingState.traverseInZOrder([&](Layer* layer) {
        bool frameLatched = layer->onPostComposition(display->getId(), glCompositionDoneFenceTime,
                                                     presentFenceTime, compositorTiming);
        if (frameLatched) {
            recordBufferingStats(layer->getName().string(),
                    layer->getOccupancyHistory(false));
        }
    });

    if (presentFenceTime->isValid()) {
        if (mUseScheduler) {
            mScheduler->addPresentFence(presentFenceTime);
        } else {
            if (mPrimaryDispSync->addPresentFence(presentFenceTime)) {
                enableHardwareVsync();
            } else {
                disableHardwareVsync(false);
            }
        }
    }

    if (!hasSyncFramework) {
        if (display && getHwComposer().isConnected(*display->getId()) && display->isPoweredOn()) {
            if (mUseScheduler) {
                mScheduler->enableHardwareVsync();
            } else {
                enableHardwareVsync();
            }
        }
    }

    if (mAnimCompositionPending) {
        mAnimCompositionPending = false;

        if (presentFenceTime->isValid()) {
            mAnimFrameTracker.setActualPresentFence(
                    std::move(presentFenceTime));
        } else if (display && getHwComposer().isConnected(*display->getId())) {
            // The HWC doesn't support present fences, so use the refresh
            // timestamp instead.
            const nsecs_t presentTime = getHwComposer().getRefreshTimestamp(*display->getId());
            mAnimFrameTracker.setActualPresentTime(presentTime);
        }
        mAnimFrameTracker.advanceFrame();
    }

    mTimeStats.incrementTotalFrames();
    if (mHadClientComposition) {
        mTimeStats.incrementClientCompositionFrames();
    }

    mTimeStats.setPresentFenceGlobal(presentFenceTime);

    if (display && getHwComposer().isConnected(*display->getId()) && !display->isPoweredOn()) {
        return;
    }

    nsecs_t currentTime = systemTime();
    if (mHasPoweredOff) {
        mHasPoweredOff = false;
    } else {
        nsecs_t elapsedTime = currentTime - getBE().mLastSwapTime;
        size_t numPeriods = static_cast<size_t>(elapsedTime / stats.vsyncPeriod);
        if (numPeriods < SurfaceFlingerBE::NUM_BUCKETS - 1) {
            getBE().mFrameBuckets[numPeriods] += elapsedTime;
        } else {
            getBE().mFrameBuckets[SurfaceFlingerBE::NUM_BUCKETS - 1] += elapsedTime;
        }
        getBE().mTotalTime += elapsedTime;
    }
    getBE().mLastSwapTime = currentTime;

    {
        std::lock_guard lock(mTexturePoolMutex);
        const size_t refillCount = mTexturePoolSize - mTexturePool.size();
        if (refillCount > 0) {
            const size_t offset = mTexturePool.size();
            mTexturePool.resize(mTexturePoolSize);
            getRenderEngine().genTextures(refillCount, mTexturePool.data() + offset);
            ATRACE_INT("TexturePoolSize", mTexturePool.size());
        }
    }

    mTransactionCompletedThread.addPresentFence(mPreviousPresentFence);
    mTransactionCompletedThread.sendCallbacks();
}

void SurfaceFlinger::rebuildLayerStacks() {
    ATRACE_CALL();
    ALOGV("rebuildLayerStacks");

    // We need to clear these out now as these may be holding on to a
    // HWC2::Layer reference at the same time as the LayerBE::HWCInfo structure
    // also holds a reference. When the set of visible layers is recomputed,
    // some layers may be destroyed if the only thing keeping them alive was
    // that list of visible layers associated with each display. The layer
    // destruction code asserts that the HWC2::Layer is properly destroyed, but
    // that doesn't happen if SurfaceFlingerBE::mCompositionInfo keeps it alive.
    for (const auto& [token, display] : mDisplays) {
        getBE().mCompositionInfo[token].clear();
    }

    // rebuild the visible layer list per screen
    if (CC_UNLIKELY(mVisibleRegionsDirty)) {
        ATRACE_NAME("rebuildLayerStacks VR Dirty");
        mVisibleRegionsDirty = false;
        invalidateHwcGeometry();

        for (const auto& pair : mDisplays) {
            const auto& display = pair.second;
            Region opaqueRegion;
            Region dirtyRegion;
            Vector<sp<Layer>> layersSortedByZ;
            Vector<sp<Layer>> layersNeedingFences;
            const ui::Transform& tr = display->getTransform();
            const Rect bounds = display->getBounds();
            if (display->isPoweredOn()) {
                computeVisibleRegions(display, dirtyRegion, opaqueRegion);

                mDrawingState.traverseInZOrder([&](Layer* layer) {
                    bool hwcLayerDestroyed = false;
                    const auto displayId = display->getId();
                    if (layer->belongsToDisplay(display->getLayerStack(), display->isPrimary())) {
                        Region drawRegion(tr.transform(
                                layer->visibleNonTransparentRegion));
                        drawRegion.andSelf(bounds);
                        if (!drawRegion.isEmpty()) {
                            layersSortedByZ.add(layer);
                        } else {
                            // Clear out the HWC layer if this layer was
                            // previously visible, but no longer is
                            hwcLayerDestroyed = displayId && layer->destroyHwcLayer(*displayId);
                        }
                    } else {
                        // WM changes display->layerStack upon sleep/awake.
                        // Here we make sure we delete the HWC layers even if
                        // WM changed their layer stack.
                        hwcLayerDestroyed = displayId && layer->destroyHwcLayer(*displayId);
                    }

                    // If a layer is not going to get a release fence because
                    // it is invisible, but it is also going to release its
                    // old buffer, add it to the list of layers needing
                    // fences.
                    if (hwcLayerDestroyed) {
                        auto found = std::find(mLayersWithQueuedFrames.cbegin(),
                                mLayersWithQueuedFrames.cend(), layer);
                        if (found != mLayersWithQueuedFrames.cend()) {
                            layersNeedingFences.add(layer);
                        }
                    }
                });
            }
            display->setVisibleLayersSortedByZ(layersSortedByZ);
            display->setLayersNeedingFences(layersNeedingFences);
            display->undefinedRegion.set(bounds);
            display->undefinedRegion.subtractSelf(tr.transform(opaqueRegion));
            display->dirtyRegion.orSelf(dirtyRegion);
        }
    }
}

// Returns a data space that fits all visible layers.  The returned data space
// can only be one of
//  - Dataspace::SRGB (use legacy dataspace and let HWC saturate when colors are enhanced)
//  - Dataspace::DISPLAY_P3
//  - Dataspace::DISPLAY_BT2020
// The returned HDR data space is one of
//  - Dataspace::UNKNOWN
//  - Dataspace::BT2020_HLG
//  - Dataspace::BT2020_PQ
Dataspace SurfaceFlinger::getBestDataspace(const sp<const DisplayDevice>& display,
                                           Dataspace* outHdrDataSpace) const {
    Dataspace bestDataSpace = Dataspace::SRGB;
    *outHdrDataSpace = Dataspace::UNKNOWN;

    for (const auto& layer : display->getVisibleLayersSortedByZ()) {
        switch (layer->getDataSpace()) {
            case Dataspace::V0_SCRGB:
            case Dataspace::V0_SCRGB_LINEAR:
            case Dataspace::BT2020:
            case Dataspace::BT2020_ITU:
            case Dataspace::BT2020_LINEAR:
            case Dataspace::DISPLAY_BT2020:
                bestDataSpace = Dataspace::DISPLAY_BT2020;
                break;
            case Dataspace::DISPLAY_P3:
                bestDataSpace = Dataspace::DISPLAY_P3;
                break;
            case Dataspace::BT2020_PQ:
            case Dataspace::BT2020_ITU_PQ:
                *outHdrDataSpace = Dataspace::BT2020_PQ;
                break;
            case Dataspace::BT2020_HLG:
            case Dataspace::BT2020_ITU_HLG:
                // When there's mixed PQ content and HLG content, we set the HDR
                // data space to be BT2020_PQ and convert HLG to PQ.
                if (*outHdrDataSpace == Dataspace::UNKNOWN) {
                    *outHdrDataSpace = Dataspace::BT2020_HLG;
                }
                break;
            default:
                break;
        }
    }

    return bestDataSpace;
}

// Pick the ColorMode / Dataspace for the display device.
void SurfaceFlinger::pickColorMode(const sp<DisplayDevice>& display, ColorMode* outMode,
                                   Dataspace* outDataSpace, RenderIntent* outRenderIntent) const {
    if (mDisplayColorSetting == DisplayColorSetting::UNMANAGED) {
        *outMode = ColorMode::NATIVE;
        *outDataSpace = Dataspace::UNKNOWN;
        *outRenderIntent = RenderIntent::COLORIMETRIC;
        return;
    }

    Dataspace hdrDataSpace;
    Dataspace bestDataSpace = getBestDataspace(display, &hdrDataSpace);

    // respect hdrDataSpace only when there is no legacy HDR support
    const bool isHdr = hdrDataSpace != Dataspace::UNKNOWN &&
        !display->hasLegacyHdrSupport(hdrDataSpace);
    if (isHdr) {
        bestDataSpace = hdrDataSpace;
    }

    RenderIntent intent;
    switch (mDisplayColorSetting) {
        case DisplayColorSetting::MANAGED:
        case DisplayColorSetting::UNMANAGED:
            intent = isHdr ? RenderIntent::TONE_MAP_COLORIMETRIC : RenderIntent::COLORIMETRIC;
            break;
        case DisplayColorSetting::ENHANCED:
            intent = isHdr ? RenderIntent::TONE_MAP_ENHANCE : RenderIntent::ENHANCE;
            break;
        default: // vendor display color setting
            intent = static_cast<RenderIntent>(mDisplayColorSetting);
            break;
    }

    display->getBestColorMode(bestDataSpace, intent, outDataSpace, outMode, outRenderIntent);
}

void SurfaceFlinger::beginFrame(const sp<DisplayDevice>& display)
{
    bool dirty = !display->getDirtyRegion(false).isEmpty();
    bool empty = display->getVisibleLayersSortedByZ().size() == 0;
    bool wasEmpty = !display->lastCompositionHadVisibleLayers;

    // If nothing has changed (!dirty), don't recompose.
    // If something changed, but we don't currently have any visible layers,
    //   and didn't when we last did a composition, then skip it this time.
    // The second rule does two things:
    // - When all layers are removed from a display, we'll emit one black
    //   frame, then nothing more until we get new layers.
    // - When a display is created with a private layer stack, we won't
    //   emit any black frames until a layer is added to the layer stack.
    bool mustRecompose = dirty && !(empty && wasEmpty);

    const char flagPrefix[] = {'-', '+'};
    static_cast<void>(flagPrefix);
    ALOGV_IF(display->isVirtual(), "%s: %s composition for %s (%cdirty %cempty %cwasEmpty)",
             __FUNCTION__, mustRecompose ? "doing" : "skipping", display->getDebugName().c_str(),
             flagPrefix[dirty], flagPrefix[empty], flagPrefix[wasEmpty]);

    display->beginFrame(mustRecompose);

    if (mustRecompose) {
        display->lastCompositionHadVisibleLayers = !empty;
    }
}

void SurfaceFlinger::prepareFrame(const sp<DisplayDevice>& display)
{
    if (!display->isPoweredOn()) {
        return;
    }

    status_t result = display->prepareFrame(getHwComposer(),
                                            getBE().mCompositionInfo[display->getDisplayToken()]);
    ALOGE_IF(result != NO_ERROR, "prepareFrame failed for %s: %d (%s)",
             display->getDebugName().c_str(), result, strerror(-result));
}

void SurfaceFlinger::doComposition(const sp<DisplayDevice>& display, bool repaintEverything) {
    ATRACE_CALL();
    ALOGV("doComposition");

    if (display->isPoweredOn()) {
        // transform the dirty region into this screen's coordinate space
        const Region dirtyRegion(display->getDirtyRegion(repaintEverything));

        // repaint the framebuffer (if needed)
        doDisplayComposition(display, dirtyRegion);

        display->dirtyRegion.clear();
        display->flip();
    }
    postFramebuffer(display);
}

void SurfaceFlinger::postFrame()
{
    // |mStateLock| not needed as we are on the main thread
    const auto display = getDefaultDisplayDeviceLocked();
    if (display && getHwComposer().isConnected(*display->getId())) {
        uint32_t flipCount = display->getPageFlipCount();
        if (flipCount % LOG_FRAME_STATS_PERIOD == 0) {
            logFrameStats();
        }
    }
}

void SurfaceFlinger::postFramebuffer(const sp<DisplayDevice>& display)
{
    ATRACE_CALL();
    ALOGV("postFramebuffer");

    mPostFramebufferTime = systemTime();

    if (display->isPoweredOn()) {
        const auto displayId = display->getId();
        if (displayId) {
            getHwComposer().presentAndGetReleaseFences(*displayId);
        }
        display->onPresentDisplayCompleted();
        for (auto& layer : display->getVisibleLayersSortedByZ()) {
            sp<Fence> releaseFence = Fence::NO_FENCE;

            // The layer buffer from the previous frame (if any) is released
            // by HWC only when the release fence from this frame (if any) is
            // signaled.  Always get the release fence from HWC first.
            if (displayId && layer->hasHwcLayer(*displayId)) {
                releaseFence = getHwComposer().getLayerReleaseFence(*displayId,
                                                                    layer->getHwcLayer(*displayId));
            }

            // If the layer was client composited in the previous frame, we
            // need to merge with the previous client target acquire fence.
            // Since we do not track that, always merge with the current
            // client target acquire fence when it is available, even though
            // this is suboptimal.
            if (layer->getCompositionType(displayId) == HWC2::Composition::Client) {
                releaseFence = Fence::merge("LayerRelease", releaseFence,
                                            display->getClientTargetAcquireFence());
            }

            layer->getBE().onLayerDisplayed(releaseFence);
        }

        // We've got a list of layers needing fences, that are disjoint with
        // display->getVisibleLayersSortedByZ.  The best we can do is to
        // supply them with the present fence.
        if (!display->getLayersNeedingFences().isEmpty()) {
            sp<Fence> presentFence =
                    displayId ? getBE().mHwc->getPresentFence(*displayId) : Fence::NO_FENCE;
            for (auto& layer : display->getLayersNeedingFences()) {
                layer->getBE().onLayerDisplayed(presentFence);
            }
        }

        if (displayId) {
            getHwComposer().clearReleaseFences(*displayId);
        }
    }
}

void SurfaceFlinger::handleTransaction(uint32_t transactionFlags)
{
    ATRACE_CALL();

    // here we keep a copy of the drawing state (that is the state that's
    // going to be overwritten by handleTransactionLocked()) outside of
    // mStateLock so that the side-effects of the State assignment
    // don't happen with mStateLock held (which can cause deadlocks).
    State drawingState(mDrawingState);

    Mutex::Autolock _l(mStateLock);
    const nsecs_t now = systemTime();
    mDebugInTransaction = now;

    // Here we're guaranteed that some transaction flags are set
    // so we can call handleTransactionLocked() unconditionally.
    // We call getTransactionFlags(), which will also clear the flags,
    // with mStateLock held to guarantee that mCurrentState won't change
    // until the transaction is committed.

    mVsyncModulator.onTransactionHandled();
    transactionFlags = getTransactionFlags(eTransactionMask);
    handleTransactionLocked(transactionFlags);

    mLastTransactionTime = systemTime() - now;
    mDebugInTransaction = 0;
    invalidateHwcGeometry();
    // here the transaction has been committed
}

void SurfaceFlinger::processDisplayHotplugEventsLocked() {
    for (const auto& event : mPendingHotplugEvents) {
        const std::optional<DisplayIdentificationInfo> info =
                getHwComposer().onHotplug(event.hwcDisplayId, event.connection);

        if (!info) {
            continue;
        }

        if (event.connection == HWC2::Connection::Connected) {
            if (!mPhysicalDisplayTokens.count(info->id)) {
                ALOGV("Creating display %s", to_string(info->id).c_str());
                mPhysicalDisplayTokens[info->id] = new BBinder();
                DisplayDeviceState state;
                state.displayId = info->id;
                state.isSecure = true; // All physical displays are currently considered secure.
                state.displayName = info->name;
                mCurrentState.displays.add(mPhysicalDisplayTokens[info->id], state);
                mInterceptor->saveDisplayCreation(state);
            }
        } else {
            ALOGV("Removing display %s", to_string(info->id).c_str());

            ssize_t index = mCurrentState.displays.indexOfKey(mPhysicalDisplayTokens[info->id]);
            if (index >= 0) {
                const DisplayDeviceState& state = mCurrentState.displays.valueAt(index);
                mInterceptor->saveDisplayDeletion(state.sequenceId);
                mCurrentState.displays.removeItemsAt(index);
            }
            mPhysicalDisplayTokens.erase(info->id);
        }

        processDisplayChangesLocked();
    }

    mPendingHotplugEvents.clear();
}

sp<DisplayDevice> SurfaceFlinger::setupNewDisplayDeviceInternal(
        const wp<IBinder>& displayToken, const std::optional<DisplayId>& displayId,
        const DisplayDeviceState& state, const sp<DisplaySurface>& dispSurface,
        const sp<IGraphicBufferProducer>& producer) {
    DisplayDeviceCreationArgs creationArgs(this, displayToken, displayId);
    creationArgs.isVirtual = state.isVirtual();
    creationArgs.isSecure = state.isSecure;
    creationArgs.displaySurface = dispSurface;
    creationArgs.hasWideColorGamut = false;
    creationArgs.supportedPerFrameMetadata = 0;

    const bool isInternalDisplay = displayId && displayId == getInternalDisplayId();
    creationArgs.isPrimary = isInternalDisplay;

    if (useColorManagement && displayId) {
        std::vector<ColorMode> modes = getHwComposer().getColorModes(*displayId);
        for (ColorMode colorMode : modes) {
            if (isWideColorMode(colorMode)) {
                creationArgs.hasWideColorGamut = true;
            }

            std::vector<RenderIntent> renderIntents =
                    getHwComposer().getRenderIntents(*displayId, colorMode);
            creationArgs.hwcColorModes.emplace(colorMode, renderIntents);
        }
    }

    if (displayId) {
        getHwComposer().getHdrCapabilities(*displayId, &creationArgs.hdrCapabilities);
        creationArgs.supportedPerFrameMetadata =
                getHwComposer().getSupportedPerFrameMetadata(*displayId);
    }

    auto nativeWindowSurface = getFactory().createNativeWindowSurface(producer);
    auto nativeWindow = nativeWindowSurface->getNativeWindow();
    creationArgs.nativeWindow = nativeWindow;

    // Make sure that composition can never be stalled by a virtual display
    // consumer that isn't processing buffers fast enough. We have to do this
    // here, in case the display is composed entirely by HWC.
    if (state.isVirtual()) {
        nativeWindow->setSwapInterval(nativeWindow.get(), 0);
    }

    creationArgs.displayInstallOrientation =
            isInternalDisplay ? primaryDisplayOrientation : DisplayState::eOrientationDefault;

    // virtual displays are always considered enabled
    creationArgs.initialPowerMode = state.isVirtual() ? HWC_POWER_MODE_NORMAL : HWC_POWER_MODE_OFF;

    sp<DisplayDevice> display = getFactory().createDisplayDevice(std::move(creationArgs));

    if (maxFrameBufferAcquiredBuffers >= 3) {
        nativeWindowSurface->preallocateBuffers();
    }

    ColorMode defaultColorMode = ColorMode::NATIVE;
    Dataspace defaultDataSpace = Dataspace::UNKNOWN;
    if (display->hasWideColorGamut()) {
        defaultColorMode = ColorMode::SRGB;
        defaultDataSpace = Dataspace::SRGB;
    }
    setActiveColorModeInternal(display, defaultColorMode, defaultDataSpace,
                               RenderIntent::COLORIMETRIC);
    if (!state.isVirtual()) {
        LOG_ALWAYS_FATAL_IF(!displayId);
        display->setActiveConfig(getHwComposer().getActiveConfigIndex(*displayId));
    }

    display->setLayerStack(state.layerStack);
    display->setProjection(state.orientation, state.viewport, state.frame);
    display->setDisplayName(state.displayName);

    return display;
}

void SurfaceFlinger::processDisplayChangesLocked() {
    // here we take advantage of Vector's copy-on-write semantics to
    // improve performance by skipping the transaction entirely when
    // know that the lists are identical
    const KeyedVector<wp<IBinder>, DisplayDeviceState>& curr(mCurrentState.displays);
    const KeyedVector<wp<IBinder>, DisplayDeviceState>& draw(mDrawingState.displays);
    if (!curr.isIdenticalTo(draw)) {
        mVisibleRegionsDirty = true;
        const size_t cc = curr.size();
        size_t dc = draw.size();

        // find the displays that were removed
        // (ie: in drawing state but not in current state)
        // also handle displays that changed
        // (ie: displays that are in both lists)
        for (size_t i = 0; i < dc;) {
            const ssize_t j = curr.indexOfKey(draw.keyAt(i));
            if (j < 0) {
                // Save display IDs before disconnecting.
                const auto internalDisplayId = getInternalDisplayId();
                const auto externalDisplayId = getExternalDisplayId();

                // in drawing state but not in current state
                if (const auto display = getDisplayDeviceLocked(draw.keyAt(i))) {
                    display->disconnect(getHwComposer());
                }
                if (internalDisplayId && internalDisplayId == draw[i].displayId) {
                    if (mUseScheduler) {
                        mScheduler->hotplugReceived(mAppConnectionHandle,
                                                    EventThread::DisplayType::Primary, false);
                    } else {
                        mEventThread->onHotplugReceived(EventThread::DisplayType::Primary, false);
                    }
                } else if (externalDisplayId && externalDisplayId == draw[i].displayId) {
                    if (mUseScheduler) {
                        mScheduler->hotplugReceived(mAppConnectionHandle,
                                                    EventThread::DisplayType::External, false);
                    } else {
                        mEventThread->onHotplugReceived(EventThread::DisplayType::External, false);
                    }
                }
                mDisplays.erase(draw.keyAt(i));
            } else {
                // this display is in both lists. see if something changed.
                const DisplayDeviceState& state(curr[j]);
                const wp<IBinder>& displayToken = curr.keyAt(j);
                const sp<IBinder> state_binder = IInterface::asBinder(state.surface);
                const sp<IBinder> draw_binder = IInterface::asBinder(draw[i].surface);
                if (state_binder != draw_binder) {
                    // changing the surface is like destroying and
                    // recreating the DisplayDevice, so we just remove it
                    // from the drawing state, so that it get re-added
                    // below.
                    if (const auto display = getDisplayDeviceLocked(displayToken)) {
                        display->disconnect(getHwComposer());
                    }
                    mDisplays.erase(displayToken);
                    mDrawingState.displays.removeItemsAt(i);
                    dc--;
                    // at this point we must loop to the next item
                    continue;
                }

                if (const auto display = getDisplayDeviceLocked(displayToken)) {
                    if (state.layerStack != draw[i].layerStack) {
                        display->setLayerStack(state.layerStack);
                    }
                    if ((state.orientation != draw[i].orientation) ||
                        (state.viewport != draw[i].viewport) || (state.frame != draw[i].frame)) {
                        display->setProjection(state.orientation, state.viewport, state.frame);
                    }
                    if (state.width != draw[i].width || state.height != draw[i].height) {
                        display->setDisplaySize(state.width, state.height);
                    }
                }
            }
            ++i;
        }

        // find displays that were added
        // (ie: in current state but not in drawing state)
        for (size_t i = 0; i < cc; i++) {
            if (draw.indexOfKey(curr.keyAt(i)) < 0) {
                const DisplayDeviceState& state(curr[i]);

                sp<DisplaySurface> dispSurface;
                sp<IGraphicBufferProducer> producer;
                sp<IGraphicBufferProducer> bqProducer;
                sp<IGraphicBufferConsumer> bqConsumer;
                getFactory().createBufferQueue(&bqProducer, &bqConsumer, false);

                std::optional<DisplayId> displayId;
                if (state.isVirtual()) {
                    // Virtual displays without a surface are dormant:
                    // they have external state (layer stack, projection,
                    // etc.) but no internal state (i.e. a DisplayDevice).
                    if (state.surface != nullptr) {
                        // Allow VR composer to use virtual displays.
                        if (mUseHwcVirtualDisplays || getHwComposer().isUsingVrComposer()) {
                            int width = 0;
                            int status = state.surface->query(NATIVE_WINDOW_WIDTH, &width);
                            ALOGE_IF(status != NO_ERROR, "Unable to query width (%d)", status);
                            int height = 0;
                            status = state.surface->query(NATIVE_WINDOW_HEIGHT, &height);
                            ALOGE_IF(status != NO_ERROR, "Unable to query height (%d)", status);
                            int intFormat = 0;
                            status = state.surface->query(NATIVE_WINDOW_FORMAT, &intFormat);
                            ALOGE_IF(status != NO_ERROR, "Unable to query format (%d)", status);
                            auto format = static_cast<ui::PixelFormat>(intFormat);

                            displayId =
                                    getHwComposer().allocateVirtualDisplay(width, height, &format);
                        }

                        // TODO: Plumb requested format back up to consumer

                        sp<VirtualDisplaySurface> vds =
                                new VirtualDisplaySurface(getHwComposer(), displayId, state.surface,
                                                          bqProducer, bqConsumer,
                                                          state.displayName);

                        dispSurface = vds;
                        producer = vds;
                    }
                } else {
                    ALOGE_IF(state.surface != nullptr,
                             "adding a supported display, but rendering "
                             "surface is provided (%p), ignoring it",
                             state.surface.get());

                    displayId = state.displayId;
                    LOG_ALWAYS_FATAL_IF(!displayId);
                    dispSurface = new FramebufferSurface(getHwComposer(), *displayId, bqConsumer);
                    producer = bqProducer;
                }

                const wp<IBinder>& displayToken = curr.keyAt(i);
                if (dispSurface != nullptr) {
                    mDisplays.emplace(displayToken,
                                      setupNewDisplayDeviceInternal(displayToken, displayId, state,
                                                                    dispSurface, producer));
                    if (!state.isVirtual()) {
                        LOG_ALWAYS_FATAL_IF(!displayId);

                        if (displayId == getInternalDisplayId()) {
                            if (mUseScheduler) {
                                mScheduler->hotplugReceived(mAppConnectionHandle,
                                                            EventThread::DisplayType::Primary,
                                                            true);
                            } else {
                                mEventThread->onHotplugReceived(EventThread::DisplayType::Primary,
                                                                true);
                            }
                        } else if (displayId == getExternalDisplayId()) {
                            if (mUseScheduler) {
                                mScheduler->hotplugReceived(mAppConnectionHandle,
                                                            EventThread::DisplayType::External,
                                                            true);
                            } else {
                                mEventThread->onHotplugReceived(EventThread::DisplayType::External,
                                                                true);
                            }
                        }
                    }
                }
            }
        }
    }

    mDrawingState.displays = mCurrentState.displays;
}

void SurfaceFlinger::handleTransactionLocked(uint32_t transactionFlags)
{
    // Notify all layers of available frames
    mCurrentState.traverseInZOrder([](Layer* layer) {
        layer->notifyAvailableFrames();
    });

    /*
     * Traversal of the children
     * (perform the transaction for each of them if needed)
     */

    if (transactionFlags & eTraversalNeeded) {
        mCurrentState.traverseInZOrder([&](Layer* layer) {
            uint32_t trFlags = layer->getTransactionFlags(eTransactionNeeded);
            if (!trFlags) return;

            const uint32_t flags = layer->doTransaction(0);
            if (flags & Layer::eVisibleRegion)
                mVisibleRegionsDirty = true;
        });
    }

    /*
     * Perform display own transactions if needed
     */

    if (transactionFlags & eDisplayTransactionNeeded) {
        processDisplayChangesLocked();
        processDisplayHotplugEventsLocked();
    }

    if (transactionFlags & (eDisplayLayerStackChanged|eDisplayTransactionNeeded)) {
        // The transform hint might have changed for some layers
        // (either because a display has changed, or because a layer
        // as changed).
        //
        // Walk through all the layers in currentLayers,
        // and update their transform hint.
        //
        // If a layer is visible only on a single display, then that
        // display is used to calculate the hint, otherwise we use the
        // default display.
        //
        // NOTE: we do this here, rather than in rebuildLayerStacks() so that
        // the hint is set before we acquire a buffer from the surface texture.
        //
        // NOTE: layer transactions have taken place already, so we use their
        // drawing state. However, SurfaceFlinger's own transaction has not
        // happened yet, so we must use the current state layer list
        // (soon to become the drawing state list).
        //
        sp<const DisplayDevice> hintDisplay;
        uint32_t currentlayerStack = 0;
        bool first = true;
        mCurrentState.traverseInZOrder([&](Layer* layer) {
            // NOTE: we rely on the fact that layers are sorted by
            // layerStack first (so we don't have to traverse the list
            // of displays for every layer).
            uint32_t layerStack = layer->getLayerStack();
            if (first || currentlayerStack != layerStack) {
                currentlayerStack = layerStack;
                // figure out if this layerstack is mirrored
                // (more than one display) if so, pick the default display,
                // if not, pick the only display it's on.
                hintDisplay = nullptr;
                for (const auto& [token, display] : mDisplays) {
                    if (layer->belongsToDisplay(display->getLayerStack(), display->isPrimary())) {
                        if (hintDisplay) {
                            hintDisplay = nullptr;
                            break;
                        } else {
                            hintDisplay = display;
                        }
                    }
                }
            }

            if (!hintDisplay) {
                // NOTE: TEMPORARY FIX ONLY. Real fix should cause layers to
                // redraw after transform hint changes. See bug 8508397.

                // could be null when this layer is using a layerStack
                // that is not visible on any display. Also can occur at
                // screen off/on times.
                hintDisplay = getDefaultDisplayDeviceLocked();
            }

            // could be null if there is no display available at all to get
            // the transform hint from.
            if (hintDisplay) {
                layer->updateTransformHint(hintDisplay);
            }

            first = false;
        });
    }


    /*
     * Perform our own transaction if needed
     */

    if (mLayersAdded) {
        mLayersAdded = false;
        // Layers have been added.
        mVisibleRegionsDirty = true;
    }

    // some layers might have been removed, so
    // we need to update the regions they're exposing.
    if (mLayersRemoved) {
        mLayersRemoved = false;
        mVisibleRegionsDirty = true;
        mDrawingState.traverseInZOrder([&](Layer* layer) {
            if (mLayersPendingRemoval.indexOf(layer) >= 0) {
                // this layer is not visible anymore
                // TODO: we could traverse the tree from front to back and
                //       compute the actual visible region
                // TODO: we could cache the transformed region
                Region visibleReg;
                visibleReg.set(layer->computeScreenBounds());
                invalidateLayerStack(layer, visibleReg);
            }
        });
    }

    commitTransaction();

    updateCursorAsync();
}

void SurfaceFlinger::updateCursorAsync()
{
    for (const auto& [token, display] : mDisplays) {
        if (!display->getId()) {
            continue;
        }

        for (auto& layer : display->getVisibleLayersSortedByZ()) {
            layer->updateCursorPosition(display);
        }
    }
}

void SurfaceFlinger::commitTransaction()
{
    if (!mLayersPendingRemoval.isEmpty()) {
        // Notify removed layers now that they can't be drawn from
        for (const auto& l : mLayersPendingRemoval) {
            recordBufferingStats(l->getName().string(),
                    l->getOccupancyHistory(true));

            // We need to release the HWC layers when the Layer is removed
            // from the current state otherwise the HWC layer just continues
            // showing at its last configured state until we eventually
            // abandon the buffer queue.
            if (l->isRemovedFromCurrentState()) {
                l->destroyAllHwcLayers();
                // destroyAllHwcLayers traverses to children, but releasePendingBuffer
                // doesn't in other scenarios. So we have to traverse explicitly here.
                l->traverseInZOrder(LayerVector::StateSet::Drawing, [&](Layer* child) {
                    child->releasePendingBuffer(systemTime());
                });
            }
        }
        mLayersPendingRemoval.clear();
    }

    // If this transaction is part of a window animation then the next frame
    // we composite should be considered an animation as well.
    mAnimCompositionPending = mAnimTransactionPending;

    mDrawingState = mCurrentState;
    // clear the "changed" flags in current state
    mCurrentState.colorMatrixChanged = false;

    mDrawingState.traverseInZOrder([](Layer* layer) {
        layer->commitChildList();
    });
    mTransactionPending = false;
    mAnimTransactionPending = false;
    mTransactionCV.broadcast();
}

void SurfaceFlinger::computeVisibleRegions(const sp<const DisplayDevice>& display,
                                           Region& outDirtyRegion, Region& outOpaqueRegion) {
    ATRACE_CALL();
    ALOGV("computeVisibleRegions");

    Region aboveOpaqueLayers;
    Region aboveCoveredLayers;
    Region dirty;

    outDirtyRegion.clear();

    mDrawingState.traverseInReverseZOrder([&](Layer* layer) {
        // start with the whole surface at its current location
        const Layer::State& s(layer->getDrawingState());

        // only consider the layers on the given layer stack
        if (!layer->belongsToDisplay(display->getLayerStack(), display->isPrimary())) {
            return;
        }

        /*
         * opaqueRegion: area of a surface that is fully opaque.
         */
        Region opaqueRegion;

        /*
         * visibleRegion: area of a surface that is visible on screen
         * and not fully transparent. This is essentially the layer's
         * footprint minus the opaque regions above it.
         * Areas covered by a translucent surface are considered visible.
         */
        Region visibleRegion;

        /*
         * coveredRegion: area of a surface that is covered by all
         * visible regions above it (which includes the translucent areas).
         */
        Region coveredRegion;

        /*
         * transparentRegion: area of a surface that is hinted to be completely
         * transparent. This is only used to tell when the layer has no visible
         * non-transparent regions and can be removed from the layer list. It
         * does not affect the visibleRegion of this layer or any layers
         * beneath it. The hint may not be correct if apps don't respect the
         * SurfaceView restrictions (which, sadly, some don't).
         */
        Region transparentRegion;


        // handle hidden surfaces by setting the visible region to empty
        if (CC_LIKELY(layer->isVisible())) {
            const bool translucent = !layer->isOpaque(s);
            Rect bounds(layer->computeScreenBounds());
            visibleRegion.set(bounds);
            ui::Transform tr = layer->getTransform();
            if (!visibleRegion.isEmpty()) {
                // Remove the transparent area from the visible region
                if (translucent) {
                    if (tr.preserveRects()) {
                        // transform the transparent region
                        transparentRegion = tr.transform(layer->getActiveTransparentRegion(s));
                    } else {
                        // transformation too complex, can't do the
                        // transparent region optimization.
                        transparentRegion.clear();
                    }
                }

                // compute the opaque region
                const int32_t layerOrientation = tr.getOrientation();
                if (layer->getAlpha() == 1.0f && !translucent &&
                        ((layerOrientation & ui::Transform::ROT_INVALID) == false)) {
                    // the opaque region is the layer's footprint
                    opaqueRegion = visibleRegion;
                }
            }
        }

        if (visibleRegion.isEmpty()) {
            layer->clearVisibilityRegions();
            return;
        }

        // Clip the covered region to the visible region
        coveredRegion = aboveCoveredLayers.intersect(visibleRegion);

        // Update aboveCoveredLayers for next (lower) layer
        aboveCoveredLayers.orSelf(visibleRegion);

        // subtract the opaque region covered by the layers above us
        visibleRegion.subtractSelf(aboveOpaqueLayers);

        // compute this layer's dirty region
        if (layer->contentDirty) {
            // we need to invalidate the whole region
            dirty = visibleRegion;
            // as well, as the old visible region
            dirty.orSelf(layer->visibleRegion);
            layer->contentDirty = false;
        } else {
            /* compute the exposed region:
             *   the exposed region consists of two components:
             *   1) what's VISIBLE now and was COVERED before
             *   2) what's EXPOSED now less what was EXPOSED before
             *
             * note that (1) is conservative, we start with the whole
             * visible region but only keep what used to be covered by
             * something -- which mean it may have been exposed.
             *
             * (2) handles areas that were not covered by anything but got
             * exposed because of a resize.
             */
            const Region newExposed = visibleRegion - coveredRegion;
            const Region oldVisibleRegion = layer->visibleRegion;
            const Region oldCoveredRegion = layer->coveredRegion;
            const Region oldExposed = oldVisibleRegion - oldCoveredRegion;
            dirty = (visibleRegion&oldCoveredRegion) | (newExposed-oldExposed);
        }
        dirty.subtractSelf(aboveOpaqueLayers);

        // accumulate to the screen dirty region
        outDirtyRegion.orSelf(dirty);

        // Update aboveOpaqueLayers for next (lower) layer
        aboveOpaqueLayers.orSelf(opaqueRegion);

        // Store the visible region in screen space
        layer->setVisibleRegion(visibleRegion);
        layer->setCoveredRegion(coveredRegion);
        layer->setVisibleNonTransparentRegion(
                visibleRegion.subtract(transparentRegion));
    });

    outOpaqueRegion = aboveOpaqueLayers;
}

void SurfaceFlinger::invalidateLayerStack(const sp<const Layer>& layer, const Region& dirty) {
    for (const auto& [token, display] : mDisplays) {
        if (layer->belongsToDisplay(display->getLayerStack(), display->isPrimary())) {
            display->dirtyRegion.orSelf(dirty);
        }
    }
}

bool SurfaceFlinger::handlePageFlip()
{
    ALOGV("handlePageFlip");

    nsecs_t latchTime = systemTime();

    bool visibleRegions = false;
    bool frameQueued = false;
    bool newDataLatched = false;

    // Store the set of layers that need updates. This set must not change as
    // buffers are being latched, as this could result in a deadlock.
    // Example: Two producers share the same command stream and:
    // 1.) Layer 0 is latched
    // 2.) Layer 0 gets a new frame
    // 2.) Layer 1 gets a new frame
    // 3.) Layer 1 is latched.
    // Display is now waiting on Layer 1's frame, which is behind layer 0's
    // second frame. But layer 0's second frame could be waiting on display.
    mDrawingState.traverseInZOrder([&](Layer* layer) {
        if (layer->hasReadyFrame()) {
            frameQueued = true;
            const nsecs_t expectedPresentTime = mPrimaryDispSync->expectedPresentTime();
            if (layer->shouldPresentNow(expectedPresentTime)) {
                mLayersWithQueuedFrames.push_back(layer);
            } else {
                layer->useEmptyDamage();
            }
        } else {
            layer->useEmptyDamage();
        }
    });

    for (auto& layer : mLayersWithQueuedFrames) {
        const Region dirty(layer->latchBuffer(visibleRegions, latchTime, getBE().flushFence));
        layer->useSurfaceDamage();
        invalidateLayerStack(layer, dirty);
        if (layer->isBufferLatched()) {
            newDataLatched = true;
        }
    }

    // Clear the renderengine fence here...
    // downstream code assumes that a cleared fence == NO_FENCE, so reassign to
    // clear instead of sp::clear.
    getBE().flushFence = Fence::NO_FENCE;

    mVisibleRegionsDirty |= visibleRegions;

    // If we will need to wake up at some time in the future to deal with a
    // queued frame that shouldn't be displayed during this vsync period, wake
    // up during the next vsync period to check again.
    if (frameQueued && (mLayersWithQueuedFrames.empty() || !newDataLatched)) {
        signalLayerUpdate();
    }

    // enter boot animation on first buffer latch
    if (CC_UNLIKELY(mBootStage == BootStage::BOOTLOADER && newDataLatched)) {
        ALOGI("Enter boot animation");
        mBootStage = BootStage::BOOTANIMATION;
    }

    // Only continue with the refresh if there is actually new work to do
    return !mLayersWithQueuedFrames.empty() && newDataLatched;
}

void SurfaceFlinger::invalidateHwcGeometry()
{
    mGeometryInvalid = true;
}

void SurfaceFlinger::doDisplayComposition(const sp<DisplayDevice>& display,
                                          const Region& inDirtyRegion) {
    // We only need to actually compose the display if:
    // 1) It is being handled by hardware composer, which may need this to
    //    keep its virtual display state machine in sync, or
    // 2) There is work to be done (the dirty region isn't empty)
    if (!display->getId() && inDirtyRegion.isEmpty()) {
        ALOGV("Skipping display composition");
        return;
    }

    ALOGV("doDisplayComposition");
    if (!doComposeSurfaces(display)) return;

    // swap buffers (presentation)
    display->queueBuffer(getHwComposer());
}

bool SurfaceFlinger::doComposeSurfaces(const sp<DisplayDevice>& display) {
    ALOGV("doComposeSurfaces");

    const Region bounds(display->bounds());
    const DisplayRenderArea renderArea(display);
    const auto displayId = display->getId();
    const bool hasClientComposition = getBE().mHwc->hasClientComposition(displayId);
    ATRACE_INT("hasClientComposition", hasClientComposition);

    mat4 colorMatrix;
    bool applyColorMatrix = false;
    bool needsEnhancedColorMatrix = false;

    // Framebuffer will live in this scope for GPU composition.
    std::unique_ptr<renderengine::BindNativeBufferAsFramebuffer> fbo;

    if (hasClientComposition) {
        ALOGV("hasClientComposition");

        sp<GraphicBuffer> buf = display->dequeueBuffer();

        if (buf == nullptr) {
            ALOGW("Dequeuing buffer for display [%s] failed, bailing out of "
                  "client composition for this frame",
                  display->getDisplayName().c_str());
            return false;
        }

        // Bind the framebuffer in this scope.
        fbo = std::make_unique<renderengine::BindNativeBufferAsFramebuffer>(getRenderEngine(),
                                                                            buf->getNativeBuffer());

        if (fbo->getStatus() != NO_ERROR) {
            ALOGW("Binding buffer for display [%s] failed with status: %d",
                  display->getDisplayName().c_str(), fbo->getStatus());
            return false;
        }

        Dataspace outputDataspace = Dataspace::UNKNOWN;
        if (display->hasWideColorGamut()) {
            outputDataspace = display->getCompositionDataSpace();
        }
        getBE().mRenderEngine->setOutputDataSpace(outputDataspace);
        getBE().mRenderEngine->setDisplayMaxLuminance(
                display->getHdrCapabilities().getDesiredMaxLuminance());

        const bool hasDeviceComposition = getBE().mHwc->hasDeviceComposition(displayId);
        const bool skipClientColorTransform = getBE().mHwc->hasCapability(
            HWC2::Capability::SkipClientColorTransform);

        // Compute the global color transform matrix.
        applyColorMatrix = !hasDeviceComposition && !skipClientColorTransform;
        if (applyColorMatrix) {
            colorMatrix = mDrawingState.colorMatrix;
        }

        // The current enhanced saturation matrix is designed to enhance Display P3,
        // thus we only apply this matrix when the render intent is not colorimetric
        // and the output color space is Display P3.
        needsEnhancedColorMatrix =
            (display->getActiveRenderIntent() >= RenderIntent::ENHANCE &&
             outputDataspace == Dataspace::DISPLAY_P3);
        if (needsEnhancedColorMatrix) {
            colorMatrix *= mEnhancedSaturationMatrix;
        }

        display->setViewportAndProjection();

        // Never touch the framebuffer if we don't have any framebuffer layers
        if (hasDeviceComposition) {
            // when using overlays, we assume a fully transparent framebuffer
            // NOTE: we could reduce how much we need to clear, for instance
            // remove where there are opaque FB layers. however, on some
            // GPUs doing a "clean slate" clear might be more efficient.
            // We'll revisit later if needed.
            getBE().mRenderEngine->clearWithColor(0, 0, 0, 0);
        } else {
            // we start with the whole screen area and remove the scissor part
            // we're left with the letterbox region
            // (common case is that letterbox ends-up being empty)
            const Region letterbox = bounds.subtract(display->getScissor());

            // compute the area to clear
            const Region region = display->undefinedRegion.merge(letterbox);

            // screen is already cleared here
            if (!region.isEmpty()) {
                // can happen with SurfaceView
                drawWormhole(region);
            }
        }

        const Rect& bounds = display->getBounds();
        const Rect& scissor = display->getScissor();
        if (scissor != bounds) {
            // scissor doesn't match the screen's dimensions, so we
            // need to clear everything outside of it and enable
            // the GL scissor so we don't draw anything where we shouldn't

            // enable scissor for this frame
            getBE().mRenderEngine->setScissor(scissor);
        }
    }

    /*
     * and then, render the layers targeted at the framebuffer
     */

    ALOGV("Rendering client layers");
    const ui::Transform& displayTransform = display->getTransform();
    bool firstLayer = true;
    for (auto& layer : display->getVisibleLayersSortedByZ()) {
        const Region clip(bounds.intersect(
                displayTransform.transform(layer->visibleRegion)));
        ALOGV("Layer: %s", layer->getName().string());
        ALOGV("  Composition type: %s", to_string(layer->getCompositionType(displayId)).c_str());
        if (!clip.isEmpty()) {
            switch (layer->getCompositionType(displayId)) {
                case HWC2::Composition::Cursor:
                case HWC2::Composition::Device:
                case HWC2::Composition::Sideband:
                case HWC2::Composition::SolidColor: {
                    LOG_ALWAYS_FATAL_IF(!displayId);
                    const Layer::State& state(layer->getDrawingState());
                    if (layer->getClearClientTarget(*displayId) && !firstLayer &&
                        layer->isOpaque(state) && (layer->getAlpha() == 1.0f) &&
                        hasClientComposition) {
                        // never clear the very first layer since we're
                        // guaranteed the FB is already cleared
                        layer->clearWithOpenGL(renderArea);
                    }
                    break;
                }
                case HWC2::Composition::Client: {
                    if (layer->hasColorTransform()) {
                        mat4 tmpMatrix;
                        if (applyColorMatrix) {
                            tmpMatrix = mDrawingState.colorMatrix;
                        }
                        tmpMatrix *= layer->getColorTransform();
                        if (needsEnhancedColorMatrix) {
                            tmpMatrix *= mEnhancedSaturationMatrix;
                        }
                        getRenderEngine().setColorTransform(tmpMatrix);
                    } else {
                        getRenderEngine().setColorTransform(colorMatrix);
                    }
                    layer->draw(renderArea, clip);
                    break;
                }
                default:
                    break;
            }
        } else {
            ALOGV("  Skipping for empty clip");
        }
        firstLayer = false;
    }

    // Perform some cleanup steps if we used client composition.
    if (hasClientComposition) {
        getRenderEngine().setColorTransform(mat4());
        getBE().mRenderEngine->disableScissor();
        display->finishBuffer();
        // Clear out error flags here so that we don't wait until next
        // composition to log.
        getRenderEngine().checkErrors();
    }
    return true;
}

void SurfaceFlinger::drawWormhole(const Region& region) const {
    auto& engine(getRenderEngine());
    engine.fillRegionWithColor(region, 0, 0, 0, 0);
}

status_t SurfaceFlinger::addClientLayer(const sp<Client>& client,
        const sp<IBinder>& handle,
        const sp<IGraphicBufferProducer>& gbc,
        const sp<Layer>& lbc,
        const sp<Layer>& parent)
{
    // add this layer to the current state list
    {
        Mutex::Autolock _l(mStateLock);
        if (mNumLayers >= MAX_LAYERS) {
            ALOGE("AddClientLayer failed, mNumLayers (%zu) >= MAX_LAYERS (%zu)", mNumLayers,
                  MAX_LAYERS);
            return NO_MEMORY;
        }
        if (parent == nullptr) {
            mCurrentState.layersSortedByZ.add(lbc);
        } else {
            if (parent->isRemovedFromCurrentState()) {
                ALOGE("addClientLayer called with a removed parent");
                return NAME_NOT_FOUND;
            }
            parent->addChild(lbc);
        }

        if (gbc != nullptr) {
            mGraphicBufferProducerList.insert(IInterface::asBinder(gbc).get());
            LOG_ALWAYS_FATAL_IF(mGraphicBufferProducerList.size() >
                                        mMaxGraphicBufferProducerListSize,
                                "Suspected IGBP leak: %zu IGBPs (%zu max), %zu Layers",
                                mGraphicBufferProducerList.size(),
                                mMaxGraphicBufferProducerListSize, mNumLayers);
        }
        mLayersAdded = true;
    }

    // attach this layer to the client
    client->attachLayer(handle, lbc);

    return NO_ERROR;
}

status_t SurfaceFlinger::removeLayer(const sp<Layer>& layer) {
    Mutex::Autolock _l(mStateLock);
    return removeLayerLocked(mStateLock, layer);
}

status_t SurfaceFlinger::removeLayerLocked(const Mutex& lock, const sp<Layer>& layer) {
    if (layer->isLayerDetached()) {
        return NO_ERROR;
    }

    const auto& p = layer->getParent();
    ssize_t index;
    if (p != nullptr) {
        index = p->removeChild(layer);
    } else {
        index = mCurrentState.layersSortedByZ.remove(layer);
    }

    layer->onRemovedFromCurrentState();

    markLayerPendingRemovalLocked(lock, layer);
    return NO_ERROR;
}

uint32_t SurfaceFlinger::peekTransactionFlags() {
    return mTransactionFlags;
}

uint32_t SurfaceFlinger::getTransactionFlags(uint32_t flags) {
    return mTransactionFlags.fetch_and(~flags) & flags;
}

uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags) {
    return setTransactionFlags(flags, Scheduler::TransactionStart::NORMAL);
}

uint32_t SurfaceFlinger::setTransactionFlags(uint32_t flags,
                                             Scheduler::TransactionStart transactionStart) {
    uint32_t old = mTransactionFlags.fetch_or(flags);
    mVsyncModulator.setTransactionStart(transactionStart);
    if ((old & flags)==0) { // wake the server up
        signalTransaction();
    }
    return old;
}

bool SurfaceFlinger::containsAnyInvalidClientState(const Vector<ComposerState>& states) {
    for (const ComposerState& state : states) {
        // Here we need to check that the interface we're given is indeed
        // one of our own. A malicious client could give us a nullptr
        // IInterface, or one of its own or even one of our own but a
        // different type. All these situations would cause us to crash.
        if (state.client == nullptr) {
            return true;
        }

        sp<IBinder> binder = IInterface::asBinder(state.client);
        if (binder == nullptr) {
            return true;
        }

        if (binder->queryLocalInterface(ISurfaceComposerClient::descriptor) == nullptr) {
            return true;
        }
    }
    return false;
}

void SurfaceFlinger::setTransactionState(
        const Vector<ComposerState>& states,
        const Vector<DisplayState>& displays,
        uint32_t flags)
{
    ATRACE_CALL();
    Mutex::Autolock _l(mStateLock);
    uint32_t transactionFlags = 0;

    if (containsAnyInvalidClientState(states)) {
        return;
    }

    if (flags & eAnimation) {
        // For window updates that are part of an animation we must wait for
        // previous animation "frames" to be handled.
        while (mAnimTransactionPending) {
            status_t err = mTransactionCV.waitRelative(mStateLock, s2ns(5));
            if (CC_UNLIKELY(err != NO_ERROR)) {
                // just in case something goes wrong in SF, return to the
                // caller after a few seconds.
                ALOGW_IF(err == TIMED_OUT, "setTransactionState timed out "
                        "waiting for previous animation frame");
                mAnimTransactionPending = false;
                break;
            }
        }
    }

    for (const DisplayState& display : displays) {
        transactionFlags |= setDisplayStateLocked(display);
    }

    uint32_t clientStateFlags = 0;
    for (const ComposerState& state : states) {
        clientStateFlags |= setClientStateLocked(state);
    }
    // If the state doesn't require a traversal and there are callbacks, send them now
    if (!(clientStateFlags & eTraversalNeeded)) {
        mTransactionCompletedThread.sendCallbacks();
    }
    transactionFlags |= clientStateFlags;

    // Iterate through all layers again to determine if any need to be destroyed. Marking layers
    // as destroyed should only occur after setting all other states. This is to allow for a
    // child re-parent to happen before marking its original parent as destroyed (which would
    // then mark the child as destroyed).
    for (const ComposerState& state : states) {
        setDestroyStateLocked(state);
    }

    // If a synchronous transaction is explicitly requested without any changes, force a transaction
    // anyway. This can be used as a flush mechanism for previous async transactions.
    // Empty animation transaction can be used to simulate back-pressure, so also force a
    // transaction for empty animation transactions.
    if (transactionFlags == 0 &&
            ((flags & eSynchronous) || (flags & eAnimation))) {
        transactionFlags = eTransactionNeeded;
    }

    if (transactionFlags) {
        if (mInterceptor->isEnabled()) {
            mInterceptor->saveTransaction(states, mCurrentState.displays, displays, flags);
        }

        // this triggers the transaction
        const auto start = (flags & eEarlyWakeup) ? Scheduler::TransactionStart::EARLY
                                                  : Scheduler::TransactionStart::NORMAL;
        setTransactionFlags(transactionFlags, start);

        // if this is a synchronous transaction, wait for it to take effect
        // before returning.
        if (flags & eSynchronous) {
            mTransactionPending = true;
        }
        if (flags & eAnimation) {
            mAnimTransactionPending = true;
        }
        while (mTransactionPending) {
            status_t err = mTransactionCV.waitRelative(mStateLock, s2ns(5));
            if (CC_UNLIKELY(err != NO_ERROR)) {
                // just in case something goes wrong in SF, return to the
                // called after a few seconds.
                ALOGW_IF(err == TIMED_OUT, "setTransactionState timed out!");
                mTransactionPending = false;
                break;
            }
        }
    }
}

uint32_t SurfaceFlinger::setDisplayStateLocked(const DisplayState& s) {
    const ssize_t index = mCurrentState.displays.indexOfKey(s.token);
    if (index < 0) return 0;

    uint32_t flags = 0;
    DisplayDeviceState& state = mCurrentState.displays.editValueAt(index);

    const uint32_t what = s.what;
    if (what & DisplayState::eSurfaceChanged) {
        if (IInterface::asBinder(state.surface) != IInterface::asBinder(s.surface)) {
            state.surface = s.surface;
            flags |= eDisplayTransactionNeeded;
        }
    }
    if (what & DisplayState::eLayerStackChanged) {
        if (state.layerStack != s.layerStack) {
            state.layerStack = s.layerStack;
            flags |= eDisplayTransactionNeeded;
        }
    }
    if (what & DisplayState::eDisplayProjectionChanged) {
        if (state.orientation != s.orientation) {
            state.orientation = s.orientation;
            flags |= eDisplayTransactionNeeded;
        }
        if (state.frame != s.frame) {
            state.frame = s.frame;
            flags |= eDisplayTransactionNeeded;
        }
        if (state.viewport != s.viewport) {
            state.viewport = s.viewport;
            flags |= eDisplayTransactionNeeded;
        }
    }
    if (what & DisplayState::eDisplaySizeChanged) {
        if (state.width != s.width) {
            state.width = s.width;
            flags |= eDisplayTransactionNeeded;
        }
        if (state.height != s.height) {
            state.height = s.height;
            flags |= eDisplayTransactionNeeded;
        }
    }

    return flags;
}

bool callingThreadHasUnscopedSurfaceFlingerAccess() {
    IPCThreadState* ipc = IPCThreadState::self();
    const int pid = ipc->getCallingPid();
    const int uid = ipc->getCallingUid();
    if ((uid != AID_GRAPHICS && uid != AID_SYSTEM) &&
        !PermissionCache::checkPermission(sAccessSurfaceFlinger, pid, uid)) {
        return false;
    }
    return true;
}

uint32_t SurfaceFlinger::setClientStateLocked(const ComposerState& composerState) {
    const layer_state_t& s = composerState.state;
    sp<Client> client(static_cast<Client*>(composerState.client.get()));

    sp<Layer> layer(client->getLayerUser(s.surface));
    if (layer == nullptr) {
        return 0;
    }

    uint32_t flags = 0;

    const uint32_t what = s.what;
    bool geometryAppliesWithResize =
            what & layer_state_t::eGeometryAppliesWithResize;

    // If we are deferring transaction, make sure to push the pending state, as otherwise the
    // pending state will also be deferred.
    if (what & layer_state_t::eDeferTransaction_legacy) {
        layer->pushPendingState();
    }

    if (what & layer_state_t::ePositionChanged) {
        if (layer->setPosition(s.x, s.y, !geometryAppliesWithResize)) {
            flags |= eTraversalNeeded;
        }
    }
    if (what & layer_state_t::eLayerChanged) {
        // NOTE: index needs to be calculated before we update the state
        const auto& p = layer->getParent();
        if (p == nullptr) {
            ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
            if (layer->setLayer(s.z) && idx >= 0) {
                mCurrentState.layersSortedByZ.removeAt(idx);
                mCurrentState.layersSortedByZ.add(layer);
                // we need traversal (state changed)
                // AND transaction (list changed)
                flags |= eTransactionNeeded|eTraversalNeeded;
            }
        } else {
            if (p->setChildLayer(layer, s.z)) {
                flags |= eTransactionNeeded|eTraversalNeeded;
            }
        }
    }
    if (what & layer_state_t::eRelativeLayerChanged) {
        // NOTE: index needs to be calculated before we update the state
        const auto& p = layer->getParent();
        if (p == nullptr) {
            ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
            if (layer->setRelativeLayer(s.relativeLayerHandle, s.z) && idx >= 0) {
                mCurrentState.layersSortedByZ.removeAt(idx);
                mCurrentState.layersSortedByZ.add(layer);
                // we need traversal (state changed)
                // AND transaction (list changed)
                flags |= eTransactionNeeded|eTraversalNeeded;
            }
        } else {
            if (p->setChildRelativeLayer(layer, s.relativeLayerHandle, s.z)) {
                flags |= eTransactionNeeded|eTraversalNeeded;
            }
        }
    }
    if (what & layer_state_t::eSizeChanged) {
        if (layer->setSize(s.w, s.h)) {
            flags |= eTraversalNeeded;
        }
    }
    if (what & layer_state_t::eAlphaChanged) {
        if (layer->setAlpha(s.alpha))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eColorChanged) {
        if (layer->setColor(s.color))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eColorTransformChanged) {
        if (layer->setColorTransform(s.colorTransform)) {
            flags |= eTraversalNeeded;
        }
    }
    if (what & layer_state_t::eMatrixChanged) {
        // TODO: b/109894387
        //
        // SurfaceFlinger's renderer is not prepared to handle cropping in the face of arbitrary
        // rotation. To see the problem observe that if we have a square parent, and a child
        // of the same size, then we rotate the child 45 degrees around it's center, the child
        // must now be cropped to a non rectangular 8 sided region.
        //
        // Of course we can fix this in the future. For now, we are lucky, SurfaceControl is
        // private API, and the WindowManager only uses rotation in one case, which is on a top
        // level layer in which cropping is not an issue.
        //
        // However given that abuse of rotation matrices could lead to surfaces extending outside
        // of cropped areas, we need to prevent non-root clients without permission ACCESS_SURFACE_FLINGER
        // (a.k.a. everyone except WindowManager and tests) from setting non rectangle preserving
        // transformations.
        if (layer->setMatrix(s.matrix, callingThreadHasUnscopedSurfaceFlingerAccess()))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eTransparentRegionChanged) {
        if (layer->setTransparentRegionHint(s.transparentRegion))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eFlagsChanged) {
        if (layer->setFlags(s.flags, s.mask))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eCropChanged_legacy) {
        if (layer->setCrop_legacy(s.crop_legacy, !geometryAppliesWithResize))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eLayerStackChanged) {
        ssize_t idx = mCurrentState.layersSortedByZ.indexOf(layer);
        // We only allow setting layer stacks for top level layers,
        // everything else inherits layer stack from its parent.
        if (layer->hasParent()) {
            ALOGE("Attempt to set layer stack on layer with parent (%s) is invalid",
                    layer->getName().string());
        } else if (idx < 0) {
            ALOGE("Attempt to set layer stack on layer without parent (%s) that "
                    "that also does not appear in the top level layer list. Something"
                    " has gone wrong.", layer->getName().string());
        } else if (layer->setLayerStack(s.layerStack)) {
            mCurrentState.layersSortedByZ.removeAt(idx);
            mCurrentState.layersSortedByZ.add(layer);
            // we need traversal (state changed)
            // AND transaction (list changed)
            flags |= eTransactionNeeded|eTraversalNeeded|eDisplayLayerStackChanged;
        }
    }
    if (what & layer_state_t::eDeferTransaction_legacy) {
        if (s.barrierHandle_legacy != nullptr) {
            layer->deferTransactionUntil_legacy(s.barrierHandle_legacy, s.frameNumber_legacy);
        } else if (s.barrierGbp_legacy != nullptr) {
            const sp<IGraphicBufferProducer>& gbp = s.barrierGbp_legacy;
            if (authenticateSurfaceTextureLocked(gbp)) {
                const auto& otherLayer =
                    (static_cast<MonitoredProducer*>(gbp.get()))->getLayer();
                layer->deferTransactionUntil_legacy(otherLayer, s.frameNumber_legacy);
            } else {
                ALOGE("Attempt to defer transaction to to an"
                        " unrecognized GraphicBufferProducer");
            }
        }
        // We don't trigger a traversal here because if no other state is
        // changed, we don't want this to cause any more work
    }
    if (what & layer_state_t::eReparent) {
        bool hadParent = layer->hasParent();
        if (layer->reparent(s.parentHandleForChild)) {
            if (!hadParent) {
                mCurrentState.layersSortedByZ.remove(layer);
            }
            flags |= eTransactionNeeded|eTraversalNeeded;
        }
    }
    if (what & layer_state_t::eReparentChildren) {
        if (layer->reparentChildren(s.reparentHandle)) {
            flags |= eTransactionNeeded|eTraversalNeeded;
        }
    }
    if (what & layer_state_t::eDetachChildren) {
        layer->detachChildren();
    }
    if (what & layer_state_t::eOverrideScalingModeChanged) {
        layer->setOverrideScalingMode(s.overrideScalingMode);
        // We don't trigger a traversal here because if no other state is
        // changed, we don't want this to cause any more work
    }
    if (what & layer_state_t::eTransformChanged) {
        if (layer->setTransform(s.transform)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eTransformToDisplayInverseChanged) {
        if (layer->setTransformToDisplayInverse(s.transformToDisplayInverse))
            flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eCropChanged) {
        if (layer->setCrop(s.crop)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eBufferChanged) {
        if (layer->setBuffer(s.buffer)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eAcquireFenceChanged) {
        if (layer->setAcquireFence(s.acquireFence)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eDataspaceChanged) {
        if (layer->setDataspace(s.dataspace)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eHdrMetadataChanged) {
        if (layer->setHdrMetadata(s.hdrMetadata)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eSurfaceDamageRegionChanged) {
        if (layer->setSurfaceDamageRegion(s.surfaceDamageRegion)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eApiChanged) {
        if (layer->setApi(s.api)) flags |= eTraversalNeeded;
    }
    if (what & layer_state_t::eSidebandStreamChanged) {
        if (layer->setSidebandStream(s.sidebandStream)) flags |= eTraversalNeeded;
    }

    std::vector<sp<CallbackHandle>> callbackHandles;
    if ((what & layer_state_t::eListenerCallbacksChanged) && (!s.listenerCallbacks.empty())) {
        mTransactionCompletedThread.run();
        for (const auto& [listener, callbackIds] : s.listenerCallbacks) {
            callbackHandles.emplace_back(new CallbackHandle(listener, callbackIds, s.surface));
        }
    }
    if (layer->setTransactionCompletedListeners(callbackHandles)) flags |= eTraversalNeeded;
    // Do not put anything that updates layer state or modifies flags after
    // setTransactionCompletedListener
    return flags;
}

void SurfaceFlinger::setDestroyStateLocked(const ComposerState& composerState) {
    const layer_state_t& state = composerState.state;
    sp<Client> client(static_cast<Client*>(composerState.client.get()));

    sp<Layer> layer(client->getLayerUser(state.surface));
    if (layer == nullptr) {
        return;
    }

    if (state.what & layer_state_t::eDestroySurface) {
        removeLayerLocked(mStateLock, layer);
    }
}

status_t SurfaceFlinger::createLayer(
        const String8& name,
        const sp<Client>& client,
        uint32_t w, uint32_t h, PixelFormat format, uint32_t flags,
        int32_t windowType, int32_t ownerUid, sp<IBinder>* handle,
        sp<IGraphicBufferProducer>* gbp, sp<Layer>* parent)
{
    if (int32_t(w|h) < 0) {
        ALOGE("createLayer() failed, w or h is negative (w=%d, h=%d)",
                int(w), int(h));
        return BAD_VALUE;
    }

    status_t result = NO_ERROR;

    sp<Layer> layer;

    String8 uniqueName = getUniqueLayerName(name);

    switch (flags & ISurfaceComposerClient::eFXSurfaceMask) {
        case ISurfaceComposerClient::eFXSurfaceBufferQueue:
            result = createBufferQueueLayer(client, uniqueName, w, h, flags, format, handle, gbp,
                                            &layer);

            break;
        case ISurfaceComposerClient::eFXSurfaceBufferState:
            result = createBufferStateLayer(client, uniqueName, w, h, flags, handle, &layer);
            break;
        case ISurfaceComposerClient::eFXSurfaceColor:
            result = createColorLayer(client,
                    uniqueName, w, h, flags,
                    handle, &layer);
            break;
        case ISurfaceComposerClient::eFXSurfaceContainer:
            result = createContainerLayer(client,
                    uniqueName, w, h, flags,
                    handle, &layer);
            break;
        default:
            result = BAD_VALUE;
            break;
    }

    if (result != NO_ERROR) {
        return result;
    }

    // window type is WINDOW_TYPE_DONT_SCREENSHOT from SurfaceControl.java
    // TODO b/64227542
    if (windowType == 441731) {
        windowType = 2024; // TYPE_NAVIGATION_BAR_PANEL
        layer->setPrimaryDisplayOnly();
    }

    layer->setInfo(windowType, ownerUid);

    result = addClientLayer(client, *handle, *gbp, layer, *parent);
    if (result != NO_ERROR) {
        return result;
    }
    mInterceptor->saveSurfaceCreation(layer);

    setTransactionFlags(eTransactionNeeded);
    return result;
}

String8 SurfaceFlinger::getUniqueLayerName(const String8& name)
{
    bool matchFound = true;
    uint32_t dupeCounter = 0;

    // Tack on our counter whether there is a hit or not, so everyone gets a tag
    String8 uniqueName = name + "#" + String8(std::to_string(dupeCounter).c_str());

    // Grab the state lock since we're accessing mCurrentState
    Mutex::Autolock lock(mStateLock);

    // Loop over layers until we're sure there is no matching name
    while (matchFound) {
        matchFound = false;
        mCurrentState.traverseInZOrder([&](Layer* layer) {
            if (layer->getName() == uniqueName) {
                matchFound = true;
                uniqueName = name + "#" + String8(std::to_string(++dupeCounter).c_str());
            }
        });
    }

    ALOGV_IF(dupeCounter > 0, "duplicate layer name: changing %s to %s", name.c_str(),
             uniqueName.c_str());

    return uniqueName;
}

status_t SurfaceFlinger::createBufferQueueLayer(const sp<Client>& client, const String8& name,
                                                uint32_t w, uint32_t h, uint32_t flags,
                                                PixelFormat& format, sp<IBinder>* handle,
                                                sp<IGraphicBufferProducer>* gbp,
                                                sp<Layer>* outLayer) {
    // initialize the surfaces
    switch (format) {
    case PIXEL_FORMAT_TRANSPARENT:
    case PIXEL_FORMAT_TRANSLUCENT:
        format = PIXEL_FORMAT_RGBA_8888;
        break;
    case PIXEL_FORMAT_OPAQUE:
        format = PIXEL_FORMAT_RGBX_8888;
        break;
    }

    sp<BufferQueueLayer> layer =
            getFactory().createBufferQueueLayer(LayerCreationArgs(this, client, name, w, h, flags));
    status_t err = layer->setDefaultBufferProperties(w, h, format);
    if (err == NO_ERROR) {
        *handle = layer->getHandle();
        *gbp = layer->getProducer();
        *outLayer = layer;
    }

    ALOGE_IF(err, "createBufferQueueLayer() failed (%s)", strerror(-err));
    return err;
}

status_t SurfaceFlinger::createBufferStateLayer(const sp<Client>& client, const String8& name,
                                                uint32_t w, uint32_t h, uint32_t flags,
                                                sp<IBinder>* handle, sp<Layer>* outLayer) {
    sp<BufferStateLayer> layer =
            getFactory().createBufferStateLayer(LayerCreationArgs(this, client, name, w, h, flags));
    *handle = layer->getHandle();
    *outLayer = layer;

    return NO_ERROR;
}

status_t SurfaceFlinger::createColorLayer(const sp<Client>& client,
        const String8& name, uint32_t w, uint32_t h, uint32_t flags,
        sp<IBinder>* handle, sp<Layer>* outLayer)
{
    *outLayer = getFactory().createColorLayer(LayerCreationArgs(this, client, name, w, h, flags));
    *handle = (*outLayer)->getHandle();
    return NO_ERROR;
}

status_t SurfaceFlinger::createContainerLayer(const sp<Client>& client,
        const String8& name, uint32_t w, uint32_t h, uint32_t flags,
        sp<IBinder>* handle, sp<Layer>* outLayer)
{
    *outLayer =
            getFactory().createContainerLayer(LayerCreationArgs(this, client, name, w, h, flags));
    *handle = (*outLayer)->getHandle();
    return NO_ERROR;
}


status_t SurfaceFlinger::onLayerRemoved(const sp<Client>& client, const sp<IBinder>& handle)
{
    // called by a client when it wants to remove a Layer
    status_t err = NO_ERROR;
    sp<Layer> l(client->getLayerUser(handle));
    if (l != nullptr) {
        mInterceptor->saveSurfaceDeletion(l);
        err = removeLayer(l);
        ALOGE_IF(err<0 && err != NAME_NOT_FOUND,
                "error removing layer=%p (%s)", l.get(), strerror(-err));
    }
    return err;
}

void SurfaceFlinger::markLayerPendingRemovalLocked(const Mutex&, const sp<Layer>& layer) {
    mLayersPendingRemoval.add(layer);
    mLayersRemoved = true;
    setTransactionFlags(eTransactionNeeded);
}

void SurfaceFlinger::onHandleDestroyed(const sp<Layer>& layer)
{
    Mutex::Autolock lock(mStateLock);
    markLayerPendingRemovalLocked(mStateLock, layer);
}

// ---------------------------------------------------------------------------

void SurfaceFlinger::onInitializeDisplays() {
    const auto displayToken = getInternalDisplayToken();
    if (!displayToken) return;

    // reset screen orientation and use primary layer stack
    Vector<ComposerState> state;
    Vector<DisplayState> displays;
    DisplayState d;
    d.what = DisplayState::eDisplayProjectionChanged |
             DisplayState::eLayerStackChanged;
    d.token = displayToken;
    d.layerStack = 0;
    d.orientation = DisplayState::eOrientationDefault;
    d.frame.makeInvalid();
    d.viewport.makeInvalid();
    d.width = 0;
    d.height = 0;
    displays.add(d);
    setTransactionState(state, displays, 0);

    const auto display = getDisplayDevice(displayToken);
    if (!display) return;

    setPowerModeInternal(display, HWC_POWER_MODE_NORMAL, /*stateLockHeld*/ false);

    const auto activeConfig = getHwComposer().getActiveConfig(*display->getId());
    const nsecs_t period = activeConfig->getVsyncPeriod();
    mAnimFrameTracker.setDisplayRefreshPeriod(period);

    // Use phase of 0 since phase is not known.
    // Use latency of 0, which will snap to the ideal latency.
    DisplayStatInfo stats{0 /* vsyncTime */, period /* vsyncPeriod */};
    setCompositorTimingSnapped(stats, 0);
}

void SurfaceFlinger::initializeDisplays() {
    // Async since we may be called from the main thread.
    postMessageAsync(new LambdaMessage([this] { onInitializeDisplays(); }));
}

void SurfaceFlinger::setPowerModeInternal(const sp<DisplayDevice>& display, int mode,
                                          bool stateLockHeld) {
    if (display->isVirtual()) {
        ALOGE("%s: Invalid operation on virtual display", __FUNCTION__);
        return;
    }

    const auto displayId = display->getId();
    LOG_ALWAYS_FATAL_IF(!displayId);

    ALOGD("Setting power mode %d on display %s", mode, to_string(*displayId).c_str());

    int currentMode = display->getPowerMode();
    if (mode == currentMode) {
        return;
    }

    display->setPowerMode(mode);

    if (mInterceptor->isEnabled()) {
        ConditionalLock lock(mStateLock, !stateLockHeld);
        ssize_t idx = mCurrentState.displays.indexOfKey(display->getDisplayToken());
        if (idx < 0) {
            ALOGW("Surface Interceptor SavePowerMode: invalid display token");
            return;
        }
        mInterceptor->savePowerModeUpdate(mCurrentState.displays.valueAt(idx).sequenceId, mode);
    }

    if (currentMode == HWC_POWER_MODE_OFF) {
        // Turn on the display
        getHwComposer().setPowerMode(*displayId, mode);
        if (display->isPrimary() && mode != HWC_POWER_MODE_DOZE_SUSPEND) {
            if (mUseScheduler) {
                mScheduler->onScreenAcquired(mAppConnectionHandle);
            } else {
                mEventThread->onScreenAcquired();
            }
            resyncToHardwareVsync(true);
        }

        mVisibleRegionsDirty = true;
        mHasPoweredOff = true;
        repaintEverything();

        struct sched_param param = {0};
        param.sched_priority = 1;
        if (sched_setscheduler(0, SCHED_FIFO, &param) != 0) {
            ALOGW("Couldn't set SCHED_FIFO on display on");
        }
    } else if (mode == HWC_POWER_MODE_OFF) {
        // Turn off the display
        struct sched_param param = {0};
        if (sched_setscheduler(0, SCHED_OTHER, &param) != 0) {
            ALOGW("Couldn't set SCHED_OTHER on display off");
        }

        if (display->isPrimary() && currentMode != HWC_POWER_MODE_DOZE_SUSPEND) {
            if (mUseScheduler) {
                mScheduler->disableHardwareVsync(true);
            } else {
                disableHardwareVsync(true); // also cancels any in-progress resync
            }
            if (mUseScheduler) {
                mScheduler->onScreenReleased(mAppConnectionHandle);
            } else {
                mEventThread->onScreenReleased();
            }
        }

        getHwComposer().setPowerMode(*displayId, mode);
        mVisibleRegionsDirty = true;
        // from this point on, SF will stop drawing on this display
    } else if (mode == HWC_POWER_MODE_DOZE ||
               mode == HWC_POWER_MODE_NORMAL) {
        // Update display while dozing
        getHwComposer().setPowerMode(*displayId, mode);
        if (display->isPrimary() && currentMode == HWC_POWER_MODE_DOZE_SUSPEND) {
            if (mUseScheduler) {
                mScheduler->onScreenAcquired(mAppConnectionHandle);
            } else {
                mEventThread->onScreenAcquired();
            }
            resyncToHardwareVsync(true);
        }
    } else if (mode == HWC_POWER_MODE_DOZE_SUSPEND) {
        // Leave display going to doze
        if (display->isPrimary()) {
            if (mUseScheduler) {
                mScheduler->disableHardwareVsync(true);
            } else {
                disableHardwareVsync(true); // also cancels any in-progress resync
            }
            if (mUseScheduler) {
                mScheduler->onScreenReleased(mAppConnectionHandle);
            } else {
                mEventThread->onScreenReleased();
            }
        }
        getHwComposer().setPowerMode(*displayId, mode);
    } else {
        ALOGE("Attempting to set unknown power mode: %d\n", mode);
        getHwComposer().setPowerMode(*displayId, mode);
    }

    if (display->isPrimary()) {
        mTimeStats.setPowerMode(mode);
    }

    ALOGD("Finished setting power mode %d on display %s", mode, to_string(*displayId).c_str());
}

void SurfaceFlinger::setPowerMode(const sp<IBinder>& displayToken, int mode) {
    postMessageSync(new LambdaMessage([&] {
        const auto display = getDisplayDevice(displayToken);
        if (!display) {
            ALOGE("Attempt to set power mode %d for invalid display token %p", mode,
                  displayToken.get());
        } else if (display->isVirtual()) {
            ALOGW("Attempt to set power mode %d for virtual display", mode);
        } else {
            setPowerModeInternal(display, mode, /*stateLockHeld*/ false);
        }
    }));
}

// ---------------------------------------------------------------------------

status_t SurfaceFlinger::doDump(int fd, const Vector<String16>& args, bool asProto)
        NO_THREAD_SAFETY_ANALYSIS {
    String8 result;

    IPCThreadState* ipc = IPCThreadState::self();
    const int pid = ipc->getCallingPid();
    const int uid = ipc->getCallingUid();

    if ((uid != AID_SHELL) &&
            !PermissionCache::checkPermission(sDump, pid, uid)) {
        result.appendFormat("Permission Denial: "
                "can't dump SurfaceFlinger from pid=%d, uid=%d\n", pid, uid);
    } else {
        // Try to get the main lock, but give up after one second
        // (this would indicate SF is stuck, but we want to be able to
        // print something in dumpsys).
        status_t err = mStateLock.timedLock(s2ns(1));
        bool locked = (err == NO_ERROR);
        if (!locked) {
            result.appendFormat(
                    "SurfaceFlinger appears to be unresponsive (%s [%d]), "
                    "dumping anyways (no locks held)\n", strerror(-err), err);
        }

        bool dumpAll = true;
        size_t index = 0;
        size_t numArgs = args.size();

        if (numArgs) {
            if ((index < numArgs) &&
                    (args[index] == String16("--list"))) {
                index++;
                listLayersLocked(args, index, result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--latency"))) {
                index++;
                dumpStatsLocked(args, index, result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--latency-clear"))) {
                index++;
                clearStatsLocked(args, index, result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--dispsync"))) {
                index++;
                mPrimaryDispSync->dump(result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--static-screen"))) {
                index++;
                dumpStaticScreenStats(result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--frame-events"))) {
                index++;
                dumpFrameEventsLocked(result);
                dumpAll = false;
            }

            if ((index < numArgs) && (args[index] == String16("--wide-color"))) {
                index++;
                dumpWideColorInfo(result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                (args[index] == String16("--enable-layer-stats"))) {
                index++;
                mLayerStats.enable();
                dumpAll = false;
            }

            if ((index < numArgs) &&
                (args[index] == String16("--disable-layer-stats"))) {
                index++;
                mLayerStats.disable();
                dumpAll = false;
            }

            if ((index < numArgs) &&
                (args[index] == String16("--clear-layer-stats"))) {
                index++;
                mLayerStats.clear();
                dumpAll = false;
            }

            if ((index < numArgs) &&
                (args[index] == String16("--dump-layer-stats"))) {
                index++;
                mLayerStats.dump(result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                    (args[index] == String16("--frame-composition"))) {
                index++;
                dumpFrameCompositionInfo(result);
                dumpAll = false;
            }

            if ((index < numArgs) &&
                (args[index] == String16("--display-identification"))) {
                index++;
                dumpDisplayIdentificationData(result);
                dumpAll = false;
            }

            if ((index < numArgs) && (args[index] == String16("--timestats"))) {
                index++;
                mTimeStats.parseArgs(asProto, args, index, result);
                dumpAll = false;
            }
        }

        if (dumpAll) {
            if (asProto) {
                LayersProto layersProto = dumpProtoInfo(LayerVector::StateSet::Current);
                result.append(layersProto.SerializeAsString().c_str(), layersProto.ByteSize());
            } else {
                dumpAllLocked(args, index, result);
            }
        }

        if (locked) {
            mStateLock.unlock();
        }
    }
    write(fd, result.string(), result.size());
    return NO_ERROR;
}

void SurfaceFlinger::listLayersLocked(const Vector<String16>& /* args */,
        size_t& /* index */, String8& result) const
{
    mCurrentState.traverseInZOrder([&](Layer* layer) {
        result.appendFormat("%s\n", layer->getName().string());
    });
}

void SurfaceFlinger::dumpStatsLocked(const Vector<String16>& args, size_t& index,
        String8& result) const
{
    String8 name;
    if (index < args.size()) {
        name = String8(args[index]);
        index++;
    }

    if (const auto displayId = getInternalDisplayId();
        displayId && getHwComposer().isConnected(*displayId)) {
        const auto activeConfig = getHwComposer().getActiveConfig(*displayId);
        const nsecs_t period = activeConfig->getVsyncPeriod();
        result.appendFormat("%" PRId64 "\n", period);
    }

    if (name.isEmpty()) {
        mAnimFrameTracker.dumpStats(result);
    } else {
        mCurrentState.traverseInZOrder([&](Layer* layer) {
            if (name == layer->getName()) {
                layer->dumpFrameStats(result);
            }
        });
    }
}

void SurfaceFlinger::clearStatsLocked(const Vector<String16>& args, size_t& index,
        String8& /* result */)
{
    String8 name;
    if (index < args.size()) {
        name = String8(args[index]);
        index++;
    }

    mCurrentState.traverseInZOrder([&](Layer* layer) {
        if (name.isEmpty() || (name == layer->getName())) {
            layer->clearFrameStats();
        }
    });

    mAnimFrameTracker.clearStats();
}

// This should only be called from the main thread.  Otherwise it would need
// the lock and should use mCurrentState rather than mDrawingState.
void SurfaceFlinger::logFrameStats() {
    mDrawingState.traverseInZOrder([&](Layer* layer) {
        layer->logFrameStats();
    });

    mAnimFrameTracker.logAndResetStats(String8("<win-anim>"));
}

void SurfaceFlinger::appendSfConfigString(String8& result) const
{
    result.append(" [sf");

    if (isLayerTripleBufferingDisabled())
        result.append(" DISABLE_TRIPLE_BUFFERING");

    result.appendFormat(" PRESENT_TIME_OFFSET=%" PRId64 , dispSyncPresentTimeOffset);
    result.appendFormat(" FORCE_HWC_FOR_RBG_TO_YUV=%d", useHwcForRgbToYuv);
    result.appendFormat(" MAX_VIRT_DISPLAY_DIM=%" PRIu64, maxVirtualDisplaySize);
    result.appendFormat(" RUNNING_WITHOUT_SYNC_FRAMEWORK=%d", !hasSyncFramework);
    result.appendFormat(" NUM_FRAMEBUFFER_SURFACE_BUFFERS=%" PRId64,
                        maxFrameBufferAcquiredBuffers);
    result.append("]");
}

void SurfaceFlinger::dumpStaticScreenStats(String8& result) const
{
    result.appendFormat("Static screen stats:\n");
    for (size_t b = 0; b < SurfaceFlingerBE::NUM_BUCKETS - 1; ++b) {
        float bucketTimeSec = getBE().mFrameBuckets[b] / 1e9;
        float percent = 100.0f *
                static_cast<float>(getBE().mFrameBuckets[b]) / getBE().mTotalTime;
        result.appendFormat("  < %zd frames: %.3f s (%.1f%%)\n",
                b + 1, bucketTimeSec, percent);
    }
    float bucketTimeSec = getBE().mFrameBuckets[SurfaceFlingerBE::NUM_BUCKETS - 1] / 1e9;
    float percent = 100.0f *
            static_cast<float>(getBE().mFrameBuckets[SurfaceFlingerBE::NUM_BUCKETS - 1]) / getBE().mTotalTime;
    result.appendFormat("  %zd+ frames: %.3f s (%.1f%%)\n",
            SurfaceFlingerBE::NUM_BUCKETS - 1, bucketTimeSec, percent);
}

void SurfaceFlinger::recordBufferingStats(const char* layerName,
        std::vector<OccupancyTracker::Segment>&& history) {
    Mutex::Autolock lock(getBE().mBufferingStatsMutex);
    auto& stats = getBE().mBufferingStats[layerName];
    for (const auto& segment : history) {
        if (!segment.usedThirdBuffer) {
            stats.twoBufferTime += segment.totalTime;
        }
        if (segment.occupancyAverage < 1.0f) {
            stats.doubleBufferedTime += segment.totalTime;
        } else if (segment.occupancyAverage < 2.0f) {
            stats.tripleBufferedTime += segment.totalTime;
        }
        ++stats.numSegments;
        stats.totalTime += segment.totalTime;
    }
}

void SurfaceFlinger::dumpFrameEventsLocked(String8& result) {
    result.appendFormat("Layer frame timestamps:\n");

    const LayerVector& currentLayers = mCurrentState.layersSortedByZ;
    const size_t count = currentLayers.size();
    for (size_t i=0 ; i<count ; i++) {
        currentLayers[i]->dumpFrameEvents(result);
    }
}

void SurfaceFlinger::dumpBufferingStats(String8& result) const {
    result.append("Buffering stats:\n");
    result.append("  [Layer name] <Active time> <Two buffer> "
            "<Double buffered> <Triple buffered>\n");
    Mutex::Autolock lock(getBE().mBufferingStatsMutex);
    typedef std::tuple<std::string, float, float, float> BufferTuple;
    std::map<float, BufferTuple, std::greater<float>> sorted;
    for (const auto& statsPair : getBE().mBufferingStats) {
        const char* name = statsPair.first.c_str();
        const SurfaceFlingerBE::BufferingStats& stats = statsPair.second;
        if (stats.numSegments == 0) {
            continue;
        }
        float activeTime = ns2ms(stats.totalTime) / 1000.0f;
        float twoBufferRatio = static_cast<float>(stats.twoBufferTime) /
                stats.totalTime;
        float doubleBufferRatio = static_cast<float>(
                stats.doubleBufferedTime) / stats.totalTime;
        float tripleBufferRatio = static_cast<float>(
                stats.tripleBufferedTime) / stats.totalTime;
        sorted.insert({activeTime, {name, twoBufferRatio,
                doubleBufferRatio, tripleBufferRatio}});
    }
    for (const auto& sortedPair : sorted) {
        float activeTime = sortedPair.first;
        const BufferTuple& values = sortedPair.second;
        result.appendFormat("  [%s] %.2f %.3f %.3f %.3f\n",
                std::get<0>(values).c_str(), activeTime,
                std::get<1>(values), std::get<2>(values),
                std::get<3>(values));
    }
    result.append("\n");
}

void SurfaceFlinger::dumpDisplayIdentificationData(String8& result) const {
    for (const auto& [token, display] : mDisplays) {
        const auto displayId = display->getId();
        if (!displayId) {
            continue;
        }
        const auto hwcDisplayId = getHwComposer().fromPhysicalDisplayId(*displayId);
        if (!hwcDisplayId) {
            continue;
        }

        result.appendFormat("Display %s (HWC display %" PRIu64 "): ", to_string(*displayId).c_str(),
                            *hwcDisplayId);
        uint8_t port;
        DisplayIdentificationData data;
        if (!getHwComposer().getDisplayIdentificationData(*hwcDisplayId, &port, &data)) {
            result.append("no identification data\n");
            continue;
        }

        if (!isEdid(data)) {
            result.append("unknown identification data: ");
            for (uint8_t byte : data) {
                result.appendFormat("%x ", byte);
            }
            result.append("\n");
            continue;
        }

        const auto edid = parseEdid(data);
        if (!edid) {
            result.append("invalid EDID: ");
            for (uint8_t byte : data) {
                result.appendFormat("%x ", byte);
            }
            result.append("\n");
            continue;
        }

        result.appendFormat("port=%u pnpId=%s displayName=\"", port, edid->pnpId.data());
        result.append(edid->displayName.data(), edid->displayName.length());
        result.append("\"\n");
    }
}

void SurfaceFlinger::dumpWideColorInfo(String8& result) const {
    result.appendFormat("Device has wide color display: %d\n", hasWideColorDisplay);
    result.appendFormat("Device uses color management: %d\n", useColorManagement);
    result.appendFormat("DisplayColorSetting: %s\n",
            decodeDisplayColorSetting(mDisplayColorSetting).c_str());

    // TODO: print out if wide-color mode is active or not

    for (const auto& [token, display] : mDisplays) {
        const auto displayId = display->getId();
        if (!displayId) {
            continue;
        }

        result.appendFormat("Display %s color modes:\n", to_string(*displayId).c_str());
        std::vector<ColorMode> modes = getHwComposer().getColorModes(*displayId);
        for (auto&& mode : modes) {
            result.appendFormat("    %s (%d)\n", decodeColorMode(mode).c_str(), mode);
        }

        ColorMode currentMode = display->getActiveColorMode();
        result.appendFormat("    Current color mode: %s (%d)\n",
                            decodeColorMode(currentMode).c_str(), currentMode);
    }
    result.append("\n");
}

void SurfaceFlinger::dumpFrameCompositionInfo(String8& result) const {
    std::string stringResult;

    for (const auto& [token, display] : mDisplays) {
        const auto it = getBE().mEndOfFrameCompositionInfo.find(token);
        if (it == getBE().mEndOfFrameCompositionInfo.end()) {
            continue;
        }

        const auto& compositionInfoList = it->second;
        stringResult += base::StringPrintf("%s\n", display->getDebugName().c_str());
        stringResult += base::StringPrintf("numComponents: %zu\n", compositionInfoList.size());
        for (const auto& compositionInfo : compositionInfoList) {
            compositionInfo.dump(stringResult, nullptr);
            stringResult += base::StringPrintf("\n");
        }
    }

    result.append(stringResult.c_str());
}

LayersProto SurfaceFlinger::dumpProtoInfo(LayerVector::StateSet stateSet) const {
    LayersProto layersProto;
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const State& state = useDrawing ? mDrawingState : mCurrentState;
    state.traverseInZOrder([&](Layer* layer) {
        LayerProto* layerProto = layersProto.add_layers();
        layer->writeToProto(layerProto, stateSet);
    });

    return layersProto;
}

LayersProto SurfaceFlinger::dumpVisibleLayersProtoInfo(const DisplayDevice& display) const {
    LayersProto layersProto;

    SizeProto* resolution = layersProto.mutable_resolution();
    resolution->set_w(display.getWidth());
    resolution->set_h(display.getHeight());

    layersProto.set_color_mode(decodeColorMode(display.getActiveColorMode()));
    layersProto.set_color_transform(decodeColorTransform(display.getColorTransform()));
    layersProto.set_global_transform(static_cast<int32_t>(display.getOrientationTransform()));

    const auto displayId = display.getId();
    LOG_ALWAYS_FATAL_IF(!displayId);
    mDrawingState.traverseInZOrder([&](Layer* layer) {
        if (!layer->visibleRegion.isEmpty() && layer->getBE().mHwcLayers.count(*displayId)) {
            LayerProto* layerProto = layersProto.add_layers();
            layer->writeToProto(layerProto, *displayId);
        }
    });

    return layersProto;
}

void SurfaceFlinger::dumpAllLocked(const Vector<String16>& args, size_t& index,
        String8& result) const
{
    bool colorize = false;
    if (index < args.size()
            && (args[index] == String16("--color"))) {
        colorize = true;
        index++;
    }

    Colorizer colorizer(colorize);

    // figure out if we're stuck somewhere
    const nsecs_t now = systemTime();
    const nsecs_t inTransaction(mDebugInTransaction);
    nsecs_t inTransactionDuration = (inTransaction) ? now-inTransaction : 0;

    /*
     * Dump library configuration.
     */

    colorizer.bold(result);
    result.append("Build configuration:");
    colorizer.reset(result);
    appendSfConfigString(result);
    appendUiConfigString(result);
    appendGuiConfigString(result);
    result.append("\n");

    result.append("\nDisplay identification data:\n");
    dumpDisplayIdentificationData(result);

    result.append("\nWide-Color information:\n");
    dumpWideColorInfo(result);

    colorizer.bold(result);
    result.append("Sync configuration: ");
    colorizer.reset(result);
    result.append(SyncFeatures::getInstance().toString());
    result.append("\n");

    colorizer.bold(result);
    result.append("DispSync configuration:\n");
    colorizer.reset(result);

    const auto [sfEarlyOffset, appEarlyOffset] = mVsyncModulator.getEarlyOffsets();
    const auto [sfEarlyGlOffset, appEarlyGlOffset] = mVsyncModulator.getEarlyGlOffsets();
    if (const auto displayId = getInternalDisplayId();
        displayId && getHwComposer().isConnected(*displayId)) {
        const auto activeConfig = getHwComposer().getActiveConfig(*displayId);
        result.appendFormat("Display %s: app phase %" PRId64 " ns, "
                            "sf phase %" PRId64 " ns, "
                            "early app phase %" PRId64 " ns, "
                            "early sf phase %" PRId64 " ns, "
                            "early app gl phase %" PRId64 " ns, "
                            "early sf gl phase %" PRId64 " ns, "
                            "present offset %" PRId64 " ns (refresh %" PRId64 " ns)",
                            to_string(*displayId).c_str(), vsyncPhaseOffsetNs, sfVsyncPhaseOffsetNs,
                            appEarlyOffset, sfEarlyOffset, appEarlyGlOffset, sfEarlyGlOffset,
                            dispSyncPresentTimeOffset, activeConfig->getVsyncPeriod());
    }
    result.append("\n");

    // Dump static screen stats
    result.append("\n");
    dumpStaticScreenStats(result);
    result.append("\n");

    result.appendFormat("Missed frame count: %u\n\n", mFrameMissedCount.load());

    dumpBufferingStats(result);

    /*
     * Dump the visible layer list
     */
    colorizer.bold(result);
    result.appendFormat("Visible layers (count = %zu)\n", mNumLayers);
    result.appendFormat("GraphicBufferProducers: %zu, max %zu\n",
                        mGraphicBufferProducerList.size(), mMaxGraphicBufferProducerListSize);
    colorizer.reset(result);

    {
        LayersProto layersProto = dumpProtoInfo(LayerVector::StateSet::Current);
        auto layerTree = LayerProtoParser::generateLayerTree(layersProto);
        result.append(LayerProtoParser::layerTreeToString(layerTree).c_str());
        result.append("\n");
    }

    result.append("\nFrame-Composition information:\n");
    dumpFrameCompositionInfo(result);
    result.append("\n");

    /*
     * Dump Display state
     */

    colorizer.bold(result);
    result.appendFormat("Displays (%zu entries)\n", mDisplays.size());
    colorizer.reset(result);
    for (const auto& [token, display] : mDisplays) {
        display->dump(result);
    }
    result.append("\n");

    /*
     * Dump SurfaceFlinger global state
     */

    colorizer.bold(result);
    result.append("SurfaceFlinger global state:\n");
    colorizer.reset(result);

    getBE().mRenderEngine->dump(result);

    if (const auto display = getDefaultDisplayDeviceLocked()) {
        display->undefinedRegion.dump(result, "undefinedRegion");
        result.appendFormat("  orientation=%d, isPoweredOn=%d\n", display->getOrientation(),
                            display->isPoweredOn());
    }
    result.appendFormat("  transaction-flags         : %08x\n"
                        "  gpu_to_cpu_unsupported    : %d\n",
                        mTransactionFlags.load(), !mGpuToCpuSupported);

    if (const auto displayId = getInternalDisplayId();
        displayId && getHwComposer().isConnected(*displayId)) {
        const auto activeConfig = getHwComposer().getActiveConfig(*displayId);
        result.appendFormat("  refresh-rate              : %f fps\n"
                            "  x-dpi                     : %f\n"
                            "  y-dpi                     : %f\n",
                            1e9 / activeConfig->getVsyncPeriod(), activeConfig->getDpiX(),
                            activeConfig->getDpiY());
    }

    result.appendFormat("  transaction time: %f us\n",
            inTransactionDuration/1000.0);

    result.appendFormat("  use Scheduler: %s\n", mUseScheduler ? "true" : "false");
    /*
     * VSYNC state
     */
    if (mUseScheduler) {
        mScheduler->dump(mAppConnectionHandle, result);
    } else {
        mEventThread->dump(result);
    }
    result.append("\n");

    /*
     * Tracing state
     */
    mTracing.dump(result);
    result.append("\n");

    /*
     * HWC layer minidump
     */
    for (const auto& [token, display] : mDisplays) {
        const auto displayId = display->getId();
        if (!displayId) {
            continue;
        }

        result.appendFormat("Display %s HWC layers:\n", to_string(*displayId).c_str());
        Layer::miniDumpHeader(result);
        mCurrentState.traverseInZOrder([&](Layer* layer) { layer->miniDump(result, *displayId); });
        result.append("\n");
    }

    /*
     * Dump HWComposer state
     */
    colorizer.bold(result);
    result.append("h/w composer state:\n");
    colorizer.reset(result);
    bool hwcDisabled = mDebugDisableHWC || mDebugRegion;
    result.appendFormat("  h/w composer %s\n",
            hwcDisabled ? "disabled" : "enabled");
    getHwComposer().dump(result);

    /*
     * Dump gralloc state
     */
    const GraphicBufferAllocator& alloc(GraphicBufferAllocator::get());
    alloc.dump(result);

    /*
     * Dump VrFlinger state if in use.
     */
    if (mVrFlingerRequestsDisplay && mVrFlinger) {
        result.append("VrFlinger state:\n");
        result.append(mVrFlinger->Dump().c_str());
        result.append("\n");
    }
}

const Vector<sp<Layer>>& SurfaceFlinger::getLayerSortedByZForHwcDisplay(DisplayId displayId) {
    // Note: mStateLock is held here
    for (const auto& [token, display] : mDisplays) {
        if (display->getId() == displayId) {
            return getDisplayDeviceLocked(token)->getVisibleLayersSortedByZ();
        }
    }

    ALOGE("%s: Invalid display %s", __FUNCTION__, to_string(displayId).c_str());
    static const Vector<sp<Layer>> empty;
    return empty;
}

bool SurfaceFlinger::startDdmConnection()
{
    void* libddmconnection_dso =
            dlopen("libsurfaceflinger_ddmconnection.so", RTLD_NOW);
    if (!libddmconnection_dso) {
        return false;
    }
    void (*DdmConnection_start)(const char* name);
    DdmConnection_start =
            (decltype(DdmConnection_start))dlsym(libddmconnection_dso, "DdmConnection_start");
    if (!DdmConnection_start) {
        dlclose(libddmconnection_dso);
        return false;
    }
    (*DdmConnection_start)(getServiceName());
    return true;
}

void SurfaceFlinger::updateColorMatrixLocked() {
    mat4 colorMatrix;
    if (mGlobalSaturationFactor != 1.0f) {
        // Rec.709 luma coefficients
        float3 luminance{0.213f, 0.715f, 0.072f};
        luminance *= 1.0f - mGlobalSaturationFactor;
        mat4 saturationMatrix = mat4(
            vec4{luminance.r + mGlobalSaturationFactor, luminance.r, luminance.r, 0.0f},
            vec4{luminance.g, luminance.g + mGlobalSaturationFactor, luminance.g, 0.0f},
            vec4{luminance.b, luminance.b, luminance.b + mGlobalSaturationFactor, 0.0f},
            vec4{0.0f, 0.0f, 0.0f, 1.0f}
        );
        colorMatrix = mClientColorMatrix * saturationMatrix * mDaltonizer();
    } else {
        colorMatrix = mClientColorMatrix * mDaltonizer();
    }

    if (mCurrentState.colorMatrix != colorMatrix) {
        mCurrentState.colorMatrix = colorMatrix;
        mCurrentState.colorMatrixChanged = true;
        setTransactionFlags(eTransactionNeeded);
    }
}

status_t SurfaceFlinger::CheckTransactCodeCredentials(uint32_t code) {
#pragma clang diagnostic push
#pragma clang diagnostic error "-Wswitch-enum"
    switch (static_cast<ISurfaceComposerTag>(code)) {
        // These methods should at minimum make sure that the client requested
        // access to SF.
        case BOOT_FINISHED:
        case CLEAR_ANIMATION_FRAME_STATS:
        case CREATE_CONNECTION:
        case CREATE_DISPLAY:
        case DESTROY_DISPLAY:
        case ENABLE_VSYNC_INJECTIONS:
        case GET_ACTIVE_COLOR_MODE:
        case GET_ANIMATION_FRAME_STATS:
        case GET_HDR_CAPABILITIES:
        case SET_ACTIVE_CONFIG:
        case SET_ACTIVE_COLOR_MODE:
        case INJECT_VSYNC:
        case SET_POWER_MODE: {
            if (!callingThreadHasUnscopedSurfaceFlingerAccess()) {
                IPCThreadState* ipc = IPCThreadState::self();
                ALOGE("Permission Denial: can't access SurfaceFlinger pid=%d, uid=%d",
                        ipc->getCallingPid(), ipc->getCallingUid());
                return PERMISSION_DENIED;
            }
            return OK;
        }
        case GET_LAYER_DEBUG_INFO: {
            IPCThreadState* ipc = IPCThreadState::self();
            const int pid = ipc->getCallingPid();
            const int uid = ipc->getCallingUid();
            if ((uid != AID_SHELL) && !PermissionCache::checkPermission(sDump, pid, uid)) {
                ALOGE("Layer debug info permission denied for pid=%d, uid=%d", pid, uid);
                return PERMISSION_DENIED;
            }
            return OK;
        }
        // Used by apps to hook Choreographer to SurfaceFlinger.
        case CREATE_DISPLAY_EVENT_CONNECTION:
        // The following calls are currently used by clients that do not
        // request necessary permissions. However, they do not expose any secret
        // information, so it is OK to pass them.
        case AUTHENTICATE_SURFACE:
        case GET_ACTIVE_CONFIG:
        case GET_BUILT_IN_DISPLAY:
        case GET_DISPLAY_COLOR_MODES:
        case GET_DISPLAY_CONFIGS:
        case GET_DISPLAY_STATS:
        case GET_SUPPORTED_FRAME_TIMESTAMPS:
        // Calling setTransactionState is safe, because you need to have been
        // granted a reference to Client* and Handle* to do anything with it.
        case SET_TRANSACTION_STATE:
        // Creating a scoped connection is safe, as per discussion in ISurfaceComposer.h
        case CREATE_SCOPED_CONNECTION:
        case GET_COLOR_MANAGEMENT:
        case GET_COMPOSITION_PREFERENCE: {
            return OK;
        }
        case CAPTURE_LAYERS:
        case CAPTURE_SCREEN: {
            // codes that require permission check
            IPCThreadState* ipc = IPCThreadState::self();
            const int pid = ipc->getCallingPid();
            const int uid = ipc->getCallingUid();
            if ((uid != AID_GRAPHICS) &&
                !PermissionCache::checkPermission(sReadFramebuffer, pid, uid)) {
                ALOGE("Permission Denial: can't read framebuffer pid=%d, uid=%d", pid, uid);
                return PERMISSION_DENIED;
            }
            return OK;
        }
        // The following codes are deprecated and should never be allowed to access SF.
        case CONNECT_DISPLAY_UNUSED:
        case CREATE_GRAPHIC_BUFFER_ALLOC_UNUSED: {
            ALOGE("Attempting to access SurfaceFlinger with unused code: %u", code);
            return PERMISSION_DENIED;
        }
    }

    // These codes are used for the IBinder protocol to either interrogate the recipient
    // side of the transaction for its canonical interface descriptor or to dump its state.
    // We let them pass by default.
    if (code == IBinder::INTERFACE_TRANSACTION || code == IBinder::DUMP_TRANSACTION ||
        code == IBinder::PING_TRANSACTION || code == IBinder::SHELL_COMMAND_TRANSACTION ||
        code == IBinder::SYSPROPS_TRANSACTION) {
        return OK;
    }
    // Numbers from 1000 to 1031 are currently use for backdoors. The code
    // in onTransact verifies that the user is root, and has access to use SF.
    if (code >= 1000 && code <= 1031) {
        ALOGV("Accessing SurfaceFlinger through backdoor code: %u", code);
        return OK;
    }
    ALOGE("Permission Denial: SurfaceFlinger did not recognize request code: %u", code);
    return PERMISSION_DENIED;
#pragma clang diagnostic pop
}

status_t SurfaceFlinger::onTransact(uint32_t code, const Parcel& data, Parcel* reply,
                                    uint32_t flags) {
    status_t credentialCheck = CheckTransactCodeCredentials(code);
    if (credentialCheck != OK) {
        return credentialCheck;
    }

    status_t err = BnSurfaceComposer::onTransact(code, data, reply, flags);
    if (err == UNKNOWN_TRANSACTION || err == PERMISSION_DENIED) {
        CHECK_INTERFACE(ISurfaceComposer, data, reply);
        IPCThreadState* ipc = IPCThreadState::self();
        const int uid = ipc->getCallingUid();
        if (CC_UNLIKELY(uid != AID_SYSTEM
                && !PermissionCache::checkCallingPermission(sHardwareTest))) {
            const int pid = ipc->getCallingPid();
            ALOGE("Permission Denial: "
                    "can't access SurfaceFlinger pid=%d, uid=%d", pid, uid);
            return PERMISSION_DENIED;
        }
        int n;
        switch (code) {
            case 1000: // SHOW_CPU, NOT SUPPORTED ANYMORE
            case 1001: // SHOW_FPS, NOT SUPPORTED ANYMORE
                return NO_ERROR;
            case 1002:  // SHOW_UPDATES
                n = data.readInt32();
                mDebugRegion = n ? n : (mDebugRegion ? 0 : 1);
                invalidateHwcGeometry();
                repaintEverything();
                return NO_ERROR;
            case 1004:{ // repaint everything
                repaintEverything();
                return NO_ERROR;
            }
            case 1005:{ // force transaction
                Mutex::Autolock _l(mStateLock);
                setTransactionFlags(
                        eTransactionNeeded|
                        eDisplayTransactionNeeded|
                        eTraversalNeeded);
                return NO_ERROR;
            }
            case 1006:{ // send empty update
                signalRefresh();
                return NO_ERROR;
            }
            case 1008:  // toggle use of hw composer
                n = data.readInt32();
                mDebugDisableHWC = n ? 1 : 0;
                invalidateHwcGeometry();
                repaintEverything();
                return NO_ERROR;
            case 1009:  // toggle use of transform hint
                n = data.readInt32();
                mDebugDisableTransformHint = n ? 1 : 0;
                invalidateHwcGeometry();
                repaintEverything();
                return NO_ERROR;
            case 1010:  // interrogate.
                reply->writeInt32(0);
                reply->writeInt32(0);
                reply->writeInt32(mDebugRegion);
                reply->writeInt32(0);
                reply->writeInt32(mDebugDisableHWC);
                return NO_ERROR;
            case 1013: {
                const auto display = getDefaultDisplayDevice();
                if (!display) {
                    return NAME_NOT_FOUND;
                }

                reply->writeInt32(display->getPageFlipCount());
                return NO_ERROR;
            }
            case 1014: {
                Mutex::Autolock _l(mStateLock);
                // daltonize
                n = data.readInt32();
                switch (n % 10) {
                    case 1:
                        mDaltonizer.setType(ColorBlindnessType::Protanomaly);
                        break;
                    case 2:
                        mDaltonizer.setType(ColorBlindnessType::Deuteranomaly);
                        break;
                    case 3:
                        mDaltonizer.setType(ColorBlindnessType::Tritanomaly);
                        break;
                    default:
                        mDaltonizer.setType(ColorBlindnessType::None);
                        break;
                }
                if (n >= 10) {
                    mDaltonizer.setMode(ColorBlindnessMode::Correction);
                } else {
                    mDaltonizer.setMode(ColorBlindnessMode::Simulation);
                }

                updateColorMatrixLocked();
                return NO_ERROR;
            }
            case 1015: {
                Mutex::Autolock _l(mStateLock);
                // apply a color matrix
                n = data.readInt32();
                if (n) {
                    // color matrix is sent as a column-major mat4 matrix
                    for (size_t i = 0 ; i < 4; i++) {
                        for (size_t j = 0; j < 4; j++) {
                            mClientColorMatrix[i][j] = data.readFloat();
                        }
                    }
                } else {
                    mClientColorMatrix = mat4();
                }

                // Check that supplied matrix's last row is {0,0,0,1} so we can avoid
                // the division by w in the fragment shader
                float4 lastRow(transpose(mClientColorMatrix)[3]);
                if (any(greaterThan(abs(lastRow - float4{0, 0, 0, 1}), float4{1e-4f}))) {
                    ALOGE("The color transform's last row must be (0, 0, 0, 1)");
                }

                updateColorMatrixLocked();
                return NO_ERROR;
            }
            // This is an experimental interface
            // Needs to be shifted to proper binder interface when we productize
            case 1016: {
                n = data.readInt32();
                // TODO(b/113612090): Evaluate if this can be removed.
                mPrimaryDispSync->setRefreshSkipCount(n);
                return NO_ERROR;
            }
            case 1017: {
                n = data.readInt32();
                mForceFullDamage = static_cast<bool>(n);
                return NO_ERROR;
            }
            case 1018: { // Modify Choreographer's phase offset
                n = data.readInt32();
                if (mUseScheduler) {
                    mScheduler->setPhaseOffset(mAppConnectionHandle, static_cast<nsecs_t>(n));
                } else {
                    mEventThread->setPhaseOffset(static_cast<nsecs_t>(n));
                }
                return NO_ERROR;
            }
            case 1019: { // Modify SurfaceFlinger's phase offset
                n = data.readInt32();
                if (mUseScheduler) {
                    mScheduler->setPhaseOffset(mSfConnectionHandle, static_cast<nsecs_t>(n));
                } else {
                    mSFEventThread->setPhaseOffset(static_cast<nsecs_t>(n));
                }
                return NO_ERROR;
            }
            case 1020: { // Layer updates interceptor
                n = data.readInt32();
                if (n) {
                    ALOGV("Interceptor enabled");
                    mInterceptor->enable(mDrawingState.layersSortedByZ, mDrawingState.displays);
                }
                else{
                    ALOGV("Interceptor disabled");
                    mInterceptor->disable();
                }
                return NO_ERROR;
            }
            case 1021: { // Disable HWC virtual displays
                n = data.readInt32();
                mUseHwcVirtualDisplays = !n;
                return NO_ERROR;
            }
            case 1022: { // Set saturation boost
                Mutex::Autolock _l(mStateLock);
                mGlobalSaturationFactor = std::max(0.0f, std::min(data.readFloat(), 2.0f));

                updateColorMatrixLocked();
                return NO_ERROR;
            }
            case 1023: { // Set native mode
                mDisplayColorSetting = static_cast<DisplayColorSetting>(data.readInt32());
                invalidateHwcGeometry();
                repaintEverything();
                return NO_ERROR;
            }
            // Deprecate, use 1030 to check whether the device is color managed.
            case 1024: {
                return NAME_NOT_FOUND;
            }
            case 1025: { // Set layer tracing
                n = data.readInt32();
                if (n) {
                    ALOGD("LayerTracing enabled");
                    mTracing.enable();
                    doTracing("tracing.enable");
                    reply->writeInt32(NO_ERROR);
                } else {
                    ALOGD("LayerTracing disabled");
                    status_t err = mTracing.disable();
                    reply->writeInt32(err);
                }
                return NO_ERROR;
            }
            case 1026: { // Get layer tracing status
                reply->writeBool(mTracing.isEnabled());
                return NO_ERROR;
            }
            // Is a DisplayColorSetting supported?
            case 1027: {
                const auto display = getDefaultDisplayDevice();
                if (!display) {
                    return NAME_NOT_FOUND;
                }

                DisplayColorSetting setting = static_cast<DisplayColorSetting>(data.readInt32());
                switch (setting) {
                    case DisplayColorSetting::MANAGED:
                        reply->writeBool(useColorManagement);
                        break;
                    case DisplayColorSetting::UNMANAGED:
                        reply->writeBool(true);
                        break;
                    case DisplayColorSetting::ENHANCED:
                        reply->writeBool(display->hasRenderIntent(RenderIntent::ENHANCE));
                        break;
                    default: // vendor display color setting
                        reply->writeBool(
                                display->hasRenderIntent(static_cast<RenderIntent>(setting)));
                        break;
                }
                return NO_ERROR;
            }
            // Is VrFlinger active?
            case 1028: {
                Mutex::Autolock _l(mStateLock);
                reply->writeBool(getBE().mHwc->isUsingVrComposer());
                return NO_ERROR;
            }
            // Is device color managed?
            case 1030: {
                reply->writeBool(useColorManagement);
                return NO_ERROR;
            }
            // Override default composition data space
            // adb shell service call SurfaceFlinger 1031 i32 1 DATASPACE_NUMBER DATASPACE_NUMBER \
            // && adb shell stop zygote && adb shell start zygote
            // to restore: adb shell service call SurfaceFlinger 1031 i32 0 && \
            // adb shell stop zygote && adb shell start zygote
            case 1031: {
                Mutex::Autolock _l(mStateLock);
                n = data.readInt32();
                if (n) {
                    n = data.readInt32();
                    if (n) {
                        Dataspace dataspace = static_cast<Dataspace>(n);
                        if (!validateCompositionDataspace(dataspace)) {
                            return BAD_VALUE;
                        }
                        mDefaultCompositionDataspace = dataspace;
                    }
                    n = data.readInt32();
                    if (n) {
                        Dataspace dataspace = static_cast<Dataspace>(n);
                        if (!validateCompositionDataspace(dataspace)) {
                            return BAD_VALUE;
                        }
                        mWideColorGamutCompositionDataspace = dataspace;
                    }
                } else {
                    // restore composition data space.
                    mDefaultCompositionDataspace = defaultCompositionDataspace;
                    mWideColorGamutCompositionDataspace = wideColorGamutCompositionDataspace;
                }
                return NO_ERROR;
            }
        }
    }
    return err;
}

void SurfaceFlinger::repaintEverything() {
    mRepaintEverything = true;
    signalTransaction();
}

// A simple RAII class to disconnect from an ANativeWindow* when it goes out of scope
class WindowDisconnector {
public:
    WindowDisconnector(ANativeWindow* window, int api) : mWindow(window), mApi(api) {}
    ~WindowDisconnector() {
        native_window_api_disconnect(mWindow, mApi);
    }

private:
    ANativeWindow* mWindow;
    const int mApi;
};

status_t SurfaceFlinger::captureScreen(const sp<IBinder>& displayToken,
                                       sp<GraphicBuffer>* outBuffer, const Dataspace reqDataspace,
                                       const ui::PixelFormat reqPixelFormat, Rect sourceCrop,
                                       uint32_t reqWidth, uint32_t reqHeight,
                                       bool useIdentityTransform,
                                       ISurfaceComposer::Rotation rotation) {
    ATRACE_CALL();

    if (!displayToken) return BAD_VALUE;

    auto renderAreaRotation = fromSurfaceComposerRotation(rotation);

    sp<DisplayDevice> display;
    {
        Mutex::Autolock _l(mStateLock);

        display = getDisplayDeviceLocked(displayToken);
        if (!display) return BAD_VALUE;

        // set the requested width/height to the logical display viewport size
        // by default
        if (reqWidth == 0 || reqHeight == 0) {
            reqWidth = uint32_t(display->getViewport().width());
            reqHeight = uint32_t(display->getViewport().height());
        }
    }

    DisplayRenderArea renderArea(display, sourceCrop, reqWidth, reqHeight, reqDataspace,
                                 renderAreaRotation);

    auto traverseLayers = std::bind(std::mem_fn(&SurfaceFlinger::traverseLayersInDisplay), this,
                                    display, std::placeholders::_1);
    return captureScreenCommon(renderArea, traverseLayers, outBuffer, reqPixelFormat,
                               useIdentityTransform);
}

status_t SurfaceFlinger::captureLayers(const sp<IBinder>& layerHandleBinder,
                                       sp<GraphicBuffer>* outBuffer, const Dataspace reqDataspace,
                                       const ui::PixelFormat reqPixelFormat, const Rect& sourceCrop,
                                       float frameScale, bool childrenOnly) {
    ATRACE_CALL();

    class LayerRenderArea : public RenderArea {
    public:
        LayerRenderArea(SurfaceFlinger* flinger, const sp<Layer>& layer, const Rect crop,
                        int32_t reqWidth, int32_t reqHeight, Dataspace reqDataSpace,
                        bool childrenOnly)
              : RenderArea(reqWidth, reqHeight, CaptureFill::CLEAR, reqDataSpace),
                mLayer(layer),
                mCrop(crop),
                mNeedsFiltering(false),
                mFlinger(flinger),
                mChildrenOnly(childrenOnly) {}
        const ui::Transform& getTransform() const override { return mTransform; }
        Rect getBounds() const override {
            const Layer::State& layerState(mLayer->getDrawingState());
            return Rect(mLayer->getActiveWidth(layerState), mLayer->getActiveHeight(layerState));
        }
        int getHeight() const override {
            return mLayer->getActiveHeight(mLayer->getDrawingState());
        }
        int getWidth() const override { return mLayer->getActiveWidth(mLayer->getDrawingState()); }
        bool isSecure() const override { return false; }
        bool needsFiltering() const override { return mNeedsFiltering; }
        Rect getSourceCrop() const override {
            if (mCrop.isEmpty()) {
                return getBounds();
            } else {
                return mCrop;
            }
        }
        class ReparentForDrawing {
        public:
            const sp<Layer>& oldParent;
            const sp<Layer>& newParent;

            ReparentForDrawing(const sp<Layer>& oldParent, const sp<Layer>& newParent)
                  : oldParent(oldParent), newParent(newParent) {
                oldParent->setChildrenDrawingParent(newParent);
            }
            ~ReparentForDrawing() { oldParent->setChildrenDrawingParent(oldParent); }
        };

        void render(std::function<void()> drawLayers) override {
            const Rect sourceCrop = getSourceCrop();
            // no need to check rotation because there is none
            mNeedsFiltering = sourceCrop.width() != getReqWidth() ||
                sourceCrop.height() != getReqHeight();

            if (!mChildrenOnly) {
                mTransform = mLayer->getTransform().inverse();
                drawLayers();
            } else {
                Rect bounds = getBounds();
                screenshotParentLayer = mFlinger->getFactory().createContainerLayer(
                        LayerCreationArgs(mFlinger, nullptr, String8("Screenshot Parent"),
                                          bounds.getWidth(), bounds.getHeight(), 0));

                ReparentForDrawing reparent(mLayer, screenshotParentLayer);
                drawLayers();
            }
        }

    private:
        const sp<Layer> mLayer;
        const Rect mCrop;

        // In the "childrenOnly" case we reparent the children to a screenshot
        // layer which has no properties set and which does not draw.
        sp<ContainerLayer> screenshotParentLayer;
        ui::Transform mTransform;
        bool mNeedsFiltering;

        SurfaceFlinger* mFlinger;
        const bool mChildrenOnly;
    };

    auto layerHandle = reinterpret_cast<Layer::Handle*>(layerHandleBinder.get());
    auto parent = layerHandle->owner.promote();

    if (parent == nullptr || parent->isRemovedFromCurrentState()) {
        ALOGE("captureLayers called with a removed parent");
        return NAME_NOT_FOUND;
    }

    const int uid = IPCThreadState::self()->getCallingUid();
    const bool forSystem = uid == AID_GRAPHICS || uid == AID_SYSTEM;
    if (!forSystem && parent->getCurrentState().flags & layer_state_t::eLayerSecure) {
        ALOGW("Attempting to capture secure layer: PERMISSION_DENIED");
        return PERMISSION_DENIED;
    }

    Rect crop(sourceCrop);
    if (sourceCrop.width() <= 0) {
        crop.left = 0;
        crop.right = parent->getActiveWidth(parent->getCurrentState());
    }

    if (sourceCrop.height() <= 0) {
        crop.top = 0;
        crop.bottom = parent->getActiveHeight(parent->getCurrentState());
    }

    int32_t reqWidth = crop.width() * frameScale;
    int32_t reqHeight = crop.height() * frameScale;

    // really small crop or frameScale
    if (reqWidth <= 0) {
        reqWidth = 1;
    }
    if (reqHeight <= 0) {
        reqHeight = 1;
    }

    LayerRenderArea renderArea(this, parent, crop, reqWidth, reqHeight, reqDataspace, childrenOnly);

    auto traverseLayers = [parent, childrenOnly](const LayerVector::Visitor& visitor) {
        parent->traverseChildrenInZOrder(LayerVector::StateSet::Drawing, [&](Layer* layer) {
            if (!layer->isVisible()) {
                return;
            } else if (childrenOnly && layer == parent.get()) {
                return;
            }
            visitor(layer);
        });
    };
    return captureScreenCommon(renderArea, traverseLayers, outBuffer, reqPixelFormat, false);
}

status_t SurfaceFlinger::captureScreenCommon(RenderArea& renderArea,
                                             TraverseLayersFunction traverseLayers,
                                             sp<GraphicBuffer>* outBuffer,
                                             const ui::PixelFormat reqPixelFormat,
                                             bool useIdentityTransform) {
    ATRACE_CALL();

    // TODO(b/116112787) Make buffer usage a parameter.
    const uint32_t usage = GRALLOC_USAGE_SW_READ_OFTEN | GRALLOC_USAGE_SW_WRITE_OFTEN |
            GRALLOC_USAGE_HW_RENDER | GRALLOC_USAGE_HW_TEXTURE;
    *outBuffer =
            getFactory().createGraphicBuffer(renderArea.getReqWidth(), renderArea.getReqHeight(),
                                             static_cast<android_pixel_format>(reqPixelFormat), 1,
                                             usage, "screenshot");

    // This mutex protects syncFd and captureResult for communication of the return values from the
    // main thread back to this Binder thread
    std::mutex captureMutex;
    std::condition_variable captureCondition;
    std::unique_lock<std::mutex> captureLock(captureMutex);
    int syncFd = -1;
    std::optional<status_t> captureResult;

    const int uid = IPCThreadState::self()->getCallingUid();
    const bool forSystem = uid == AID_GRAPHICS || uid == AID_SYSTEM;

    sp<LambdaMessage> message = new LambdaMessage([&] {
        // If there is a refresh pending, bug out early and tell the binder thread to try again
        // after the refresh.
        if (mRefreshPending) {
            ATRACE_NAME("Skipping screenshot for now");
            std::unique_lock<std::mutex> captureLock(captureMutex);
            captureResult = std::make_optional<status_t>(EAGAIN);
            captureCondition.notify_one();
            return;
        }

        status_t result = NO_ERROR;
        int fd = -1;
        {
            Mutex::Autolock _l(mStateLock);
            renderArea.render([&] {
                result = captureScreenImplLocked(renderArea, traverseLayers, (*outBuffer).get(),
                                                 useIdentityTransform, forSystem, &fd);
            });
        }

        {
            std::unique_lock<std::mutex> captureLock(captureMutex);
            syncFd = fd;
            captureResult = std::make_optional<status_t>(result);
            captureCondition.notify_one();
        }
    });

    status_t result = postMessageAsync(message);
    if (result == NO_ERROR) {
        captureCondition.wait(captureLock, [&] { return captureResult; });
        while (*captureResult == EAGAIN) {
            captureResult.reset();
            result = postMessageAsync(message);
            if (result != NO_ERROR) {
                return result;
            }
            captureCondition.wait(captureLock, [&] { return captureResult; });
        }
        result = *captureResult;
    }

    if (result == NO_ERROR) {
        sync_wait(syncFd, -1);
        close(syncFd);
    }

    return result;
}

void SurfaceFlinger::renderScreenImplLocked(const RenderArea& renderArea,
                                            TraverseLayersFunction traverseLayers,
                                            bool useIdentityTransform) {
    ATRACE_CALL();

    auto& engine(getRenderEngine());

    const auto reqWidth = renderArea.getReqWidth();
    const auto reqHeight = renderArea.getReqHeight();
    const auto sourceCrop = renderArea.getSourceCrop();
    const auto rotation = renderArea.getRotationFlags();

    engine.setOutputDataSpace(renderArea.getReqDataSpace());
    engine.setDisplayMaxLuminance(DisplayDevice::sDefaultMaxLumiance);

    // make sure to clear all GL error flags
    engine.checkErrors();

    // set-up our viewport
    engine.setViewportAndProjection(reqWidth, reqHeight, sourceCrop, rotation);
    engine.disableTexturing();

    const float alpha = RenderArea::getCaptureFillValue(renderArea.getCaptureFill());
    // redraw the screen entirely...
    engine.clearWithColor(0, 0, 0, alpha);

    traverseLayers([&](Layer* layer) {
        engine.setColorTransform(layer->getColorTransform());
        layer->draw(renderArea, useIdentityTransform);
        engine.setColorTransform(mat4());
    });
}

status_t SurfaceFlinger::captureScreenImplLocked(const RenderArea& renderArea,
                                                 TraverseLayersFunction traverseLayers,
                                                 ANativeWindowBuffer* buffer,
                                                 bool useIdentityTransform,
                                                 bool forSystem,
                                                 int* outSyncFd) {
    ATRACE_CALL();

    bool secureLayerIsVisible = false;

    traverseLayers([&](Layer* layer) {
        secureLayerIsVisible = secureLayerIsVisible || (layer->isVisible() && layer->isSecure());
    });

    // We allow the system server to take screenshots of secure layers for
    // use in situations like the Screen-rotation animation and place
    // the impetus on WindowManager to not persist them.
    if (secureLayerIsVisible && !forSystem) {
        ALOGW("FB is protected: PERMISSION_DENIED");
        return PERMISSION_DENIED;
    }

    // this binds the given EGLImage as a framebuffer for the
    // duration of this scope.
    renderengine::BindNativeBufferAsFramebuffer bufferBond(getRenderEngine(), buffer);
    if (bufferBond.getStatus() != NO_ERROR) {
        ALOGE("got ANWB binding error while taking screenshot");
        return INVALID_OPERATION;
    }

    // this will in fact render into our dequeued buffer
    // via an FBO, which means we didn't have to create
    // an EGLSurface and therefore we're not
    // dependent on the context's EGLConfig.
    renderScreenImplLocked(renderArea, traverseLayers, useIdentityTransform);

    base::unique_fd syncFd = getRenderEngine().flush();
    if (syncFd < 0) {
        getRenderEngine().finish();
    }
    *outSyncFd = syncFd.release();

    return NO_ERROR;
}

// ---------------------------------------------------------------------------

void SurfaceFlinger::State::traverseInZOrder(const LayerVector::Visitor& visitor) const {
    layersSortedByZ.traverseInZOrder(stateSet, visitor);
}

void SurfaceFlinger::State::traverseInReverseZOrder(const LayerVector::Visitor& visitor) const {
    layersSortedByZ.traverseInReverseZOrder(stateSet, visitor);
}

void SurfaceFlinger::traverseLayersInDisplay(const sp<const DisplayDevice>& display,
                                             const LayerVector::Visitor& visitor) {
    // We loop through the first level of layers without traversing,
    // as we need to determine which layers belong to the requested display.
    for (const auto& layer : mDrawingState.layersSortedByZ) {
        if (!layer->belongsToDisplay(display->getLayerStack(), false)) {
            continue;
        }
        // relative layers are traversed in Layer::traverseInZOrder
        layer->traverseInZOrder(LayerVector::StateSet::Drawing, [&](Layer* layer) {
            if (!layer->belongsToDisplay(display->getLayerStack(), false)) {
                return;
            }
            if (!layer->isVisible()) {
                return;
            }
            visitor(layer);
        });
    }
}

}; // namespace android


#if defined(__gl_h_)
#error "don't include gl/gl.h in this file"
#endif

#if defined(__gl2_h_)
#error "don't include gl2/gl2.h in this file"
#endif