services/surfaceflinger/BufferLayer.cpp

/*
 * Copyright (C) 2017 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
#undef LOG_TAG
#define LOG_TAG "BufferLayer"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "BufferLayer.h"
#include "Colorizer.h"
#include "DisplayDevice.h"
#include "LayerRejecter.h"
#include "clz.h"

#include "RenderEngine/RenderEngine.h"

#include <gui/BufferItem.h>
#include <gui/BufferQueue.h>
#include <gui/LayerDebugInfo.h>
#include <gui/Surface.h>

#include <ui/DebugUtils.h>

#include <utils/Errors.h>
#include <utils/Log.h>
#include <utils/NativeHandle.h>
#include <utils/StopWatch.h>
#include <utils/Trace.h>

#include <cutils/compiler.h>
#include <cutils/native_handle.h>
#include <cutils/properties.h>

#include <math.h>
#include <stdlib.h>
#include <mutex>

namespace android {

BufferLayer::BufferLayer(SurfaceFlinger* flinger, const sp<Client>& client, const String8& name,
                         uint32_t w, uint32_t h, uint32_t flags)
      : Layer(flinger, client, name, w, h, flags),
        mTextureName(-1U),
        mFormat(PIXEL_FORMAT_NONE),
        mCurrentScalingMode(NATIVE_WINDOW_SCALING_MODE_FREEZE),
        mBufferLatched(false),
        mPreviousFrameNumber(0),
        mUpdateTexImageFailed(false),
        mRefreshPending(false) {
#ifdef USE_HWC2
    ALOGV("Creating Layer %s", name.string());
#endif

    mFlinger->getRenderEngine().genTextures(1, &mTextureName);
    mTexture.init(Texture::TEXTURE_EXTERNAL, mTextureName);

    if (flags & ISurfaceComposerClient::eNonPremultiplied) mPremultipliedAlpha = false;

    mCurrentState.requested = mCurrentState.active;

    // drawing state & current state are identical
    mDrawingState = mCurrentState;
}

BufferLayer::~BufferLayer() {
    sp<Client> c(mClientRef.promote());
    if (c != 0) {
        c->detachLayer(this);
    }

    for (auto& point : mRemoteSyncPoints) {
        point->setTransactionApplied();
    }
    for (auto& point : mLocalSyncPoints) {
        point->setFrameAvailable();
    }
    mFlinger->deleteTextureAsync(mTextureName);

#ifdef USE_HWC2
    if (!mHwcLayers.empty()) {
        ALOGE("Found stale hardware composer layers when destroying "
              "surface flinger layer %s",
              mName.string());
        destroyAllHwcLayers();
    }
#endif
}

bool BufferLayer::isProtected() const
{
    const sp<GraphicBuffer>& activeBuffer(mActiveBuffer);
    return (activeBuffer != 0) &&
            (activeBuffer->getUsage() & GRALLOC_USAGE_PROTECTED);
}

bool BufferLayer::isVisible() const {
    return !(isHiddenByPolicy()) && getAlpha() > 0.0f &&
            (mActiveBuffer != NULL || mSidebandStream != NULL);
}

bool BufferLayer::isFixedSize() const {
    return getEffectiveScalingMode() != NATIVE_WINDOW_SCALING_MODE_FREEZE;
}

status_t BufferLayer::setBuffers(uint32_t w, uint32_t h, PixelFormat format, uint32_t flags) {
    uint32_t const maxSurfaceDims =
            min(mFlinger->getMaxTextureSize(), mFlinger->getMaxViewportDims());

    // never allow a surface larger than what our underlying GL implementation
    // can handle.
    if ((uint32_t(w) > maxSurfaceDims) || (uint32_t(h) > maxSurfaceDims)) {
        ALOGE("dimensions too large %u x %u", uint32_t(w), uint32_t(h));
        return BAD_VALUE;
    }

    mFormat = format;

    mPotentialCursor = (flags & ISurfaceComposerClient::eCursorWindow) ? true : false;
    mProtectedByApp = (flags & ISurfaceComposerClient::eProtectedByApp) ? true : false;
    mCurrentOpacity = getOpacityForFormat(format);

    mSurfaceFlingerConsumer->setDefaultBufferSize(w, h);
    mSurfaceFlingerConsumer->setDefaultBufferFormat(format);
    mSurfaceFlingerConsumer->setConsumerUsageBits(getEffectiveUsage(0));

    return NO_ERROR;
}

static constexpr mat4 inverseOrientation(uint32_t transform) {
    const mat4 flipH(-1,0,0,0,  0,1,0,0, 0,0,1,0, 1,0,0,1);
    const mat4 flipV( 1,0,0,0, 0,-1,0,0, 0,0,1,0, 0,1,0,1);
    const mat4 rot90( 0,1,0,0, -1,0,0,0, 0,0,1,0, 1,0,0,1);
    mat4 tr;

    if (transform & NATIVE_WINDOW_TRANSFORM_ROT_90) {
        tr = tr * rot90;
    }
    if (transform & NATIVE_WINDOW_TRANSFORM_FLIP_H) {
        tr = tr * flipH;
    }
    if (transform & NATIVE_WINDOW_TRANSFORM_FLIP_V) {
        tr = tr * flipV;
    }
    return inverse(tr);
}

/*
 * onDraw will draw the current layer onto the presentable buffer
 */
void BufferLayer::onDraw(const RenderArea& renderArea, const Region& clip,
                         bool useIdentityTransform) const {
    ATRACE_CALL();

    if (CC_UNLIKELY(mActiveBuffer == 0)) {
        // the texture has not been created yet, this Layer has
        // in fact never been drawn into. This happens frequently with
        // SurfaceView because the WindowManager can't know when the client
        // has drawn the first time.

        // If there is nothing under us, we paint the screen in black, otherwise
        // we just skip this update.

        // figure out if there is something below us
        Region under;
        bool finished = false;
        mFlinger->mDrawingState.traverseInZOrder([&](Layer* layer) {
            if (finished || layer == static_cast<BufferLayer const*>(this)) {
                finished = true;
                return;
            }
            under.orSelf(renderArea.getTransform().transform(layer->visibleRegion));
        });
        // if not everything below us is covered, we plug the holes!
        Region holes(clip.subtract(under));
        if (!holes.isEmpty()) {
            clearWithOpenGL(renderArea, 0, 0, 0, 1);
        }
        return;
    }

    // Bind the current buffer to the GL texture, and wait for it to be
    // ready for us to draw into.
    status_t err = mSurfaceFlingerConsumer->bindTextureImage();
    if (err != NO_ERROR) {
        ALOGW("onDraw: bindTextureImage failed (err=%d)", err);
        // Go ahead and draw the buffer anyway; no matter what we do the screen
        // is probably going to have something visibly wrong.
    }

    bool blackOutLayer = isProtected() || (isSecure() && !renderArea.isSecure());

    RenderEngine& engine(mFlinger->getRenderEngine());

    if (!blackOutLayer) {
        // TODO: we could be more subtle with isFixedSize()
        const bool useFiltering = getFiltering() || needsFiltering(renderArea) || isFixedSize();

        // Query the texture matrix given our current filtering mode.
        float textureMatrix[16];
        mSurfaceFlingerConsumer->setFilteringEnabled(useFiltering);
        mSurfaceFlingerConsumer->getTransformMatrix(textureMatrix);

        if (getTransformToDisplayInverse()) {
            /*
             * the code below applies the primary display's inverse transform to
             * the texture transform
             */
            uint32_t transform = DisplayDevice::getPrimaryDisplayOrientationTransform();
            mat4 tr = inverseOrientation(transform);

            /**
             * TODO(b/36727915): This is basically a hack.
             *
             * Ensure that regardless of the parent transformation,
             * this buffer is always transformed from native display
             * orientation to display orientation. For example, in the case
             * of a camera where the buffer remains in native orientation,
             * we want the pixels to always be upright.
             */
            sp<Layer> p = mDrawingParent.promote();
            if (p != nullptr) {
                const auto parentTransform = p->getTransform();
                tr = tr * inverseOrientation(parentTransform.getOrientation());
            }

            // and finally apply it to the original texture matrix
            const mat4 texTransform(mat4(static_cast<const float*>(textureMatrix)) * tr);
            memcpy(textureMatrix, texTransform.asArray(), sizeof(textureMatrix));
        }

        // Set things up for texturing.
        mTexture.setDimensions(mActiveBuffer->getWidth(), mActiveBuffer->getHeight());
        mTexture.setFiltering(useFiltering);
        mTexture.setMatrix(textureMatrix);

        engine.setupLayerTexturing(mTexture);
    } else {
        engine.setupLayerBlackedOut();
    }
    drawWithOpenGL(renderArea, useIdentityTransform);
    engine.disableTexturing();
}

bool BufferLayer::onPreComposition(nsecs_t refreshStartTime) {
    if (mBufferLatched) {
        Mutex::Autolock lock(mFrameEventHistoryMutex);
        mFrameEventHistory.addPreComposition(mCurrentFrameNumber, refreshStartTime);
    }
    mRefreshPending = false;
    return mQueuedFrames > 0 || mSidebandStreamChanged || mAutoRefresh;
}

#ifdef USE_HWC2
void BufferLayer::releasePendingBuffer(nsecs_t dequeueReadyTime) {
    if (!mSurfaceFlingerConsumer->releasePendingBuffer()) {
        return;
    }

    auto releaseFenceTime =
            std::make_shared<FenceTime>(mSurfaceFlingerConsumer->getPrevFinalReleaseFence());
    mReleaseTimeline.updateSignalTimes();
    mReleaseTimeline.push(releaseFenceTime);

    Mutex::Autolock lock(mFrameEventHistoryMutex);
    if (mPreviousFrameNumber != 0) {
        mFrameEventHistory.addRelease(mPreviousFrameNumber, dequeueReadyTime,
                                      std::move(releaseFenceTime));
    }
}
#endif

Region BufferLayer::latchBuffer(bool& recomputeVisibleRegions, nsecs_t latchTime) {
    ATRACE_CALL();

    if (android_atomic_acquire_cas(true, false, &mSidebandStreamChanged) == 0) {
        // mSidebandStreamChanged was true
        mSidebandStream = mSurfaceFlingerConsumer->getSidebandStream();
        if (mSidebandStream != NULL) {
            setTransactionFlags(eTransactionNeeded);
            mFlinger->setTransactionFlags(eTraversalNeeded);
        }
        recomputeVisibleRegions = true;

        const State& s(getDrawingState());
        return getTransform().transform(Region(Rect(s.active.w, s.active.h)));
    }

    Region outDirtyRegion;
    if (mQueuedFrames <= 0 && !mAutoRefresh) {
        return outDirtyRegion;
    }

    // if we've already called updateTexImage() without going through
    // a composition step, we have to skip this layer at this point
    // because we cannot call updateTeximage() without a corresponding
    // compositionComplete() call.
    // we'll trigger an update in onPreComposition().
    if (mRefreshPending) {
        return outDirtyRegion;
    }

    // If the head buffer's acquire fence hasn't signaled yet, return and
    // try again later
    if (!headFenceHasSignaled()) {
        mFlinger->signalLayerUpdate();
        return outDirtyRegion;
    }

    // Capture the old state of the layer for comparisons later
    const State& s(getDrawingState());
    const bool oldOpacity = isOpaque(s);
    sp<GraphicBuffer> oldActiveBuffer = mActiveBuffer;

    if (!allTransactionsSignaled()) {
        mFlinger->signalLayerUpdate();
        return outDirtyRegion;
    }

    // This boolean is used to make sure that SurfaceFlinger's shadow copy
    // of the buffer queue isn't modified when the buffer queue is returning
    // BufferItem's that weren't actually queued. This can happen in shared
    // buffer mode.
    bool queuedBuffer = false;
    LayerRejecter r(mDrawingState, getCurrentState(), recomputeVisibleRegions,
                    getProducerStickyTransform() != 0, mName.string(), mOverrideScalingMode,
                    mFreezeGeometryUpdates);
    status_t updateResult =
            mSurfaceFlingerConsumer->updateTexImage(&r, mFlinger->mPrimaryDispSync, &mAutoRefresh,
                                                    &queuedBuffer, mLastFrameNumberReceived);
    if (updateResult == BufferQueue::PRESENT_LATER) {
        // Producer doesn't want buffer to be displayed yet.  Signal a
        // layer update so we check again at the next opportunity.
        mFlinger->signalLayerUpdate();
        return outDirtyRegion;
    } else if (updateResult == SurfaceFlingerConsumer::BUFFER_REJECTED) {
        // If the buffer has been rejected, remove it from the shadow queue
        // and return early
        if (queuedBuffer) {
            Mutex::Autolock lock(mQueueItemLock);
            mQueueItems.removeAt(0);
            android_atomic_dec(&mQueuedFrames);
        }
        return outDirtyRegion;
    } else if (updateResult != NO_ERROR || mUpdateTexImageFailed) {
        // This can occur if something goes wrong when trying to create the
        // EGLImage for this buffer. If this happens, the buffer has already
        // been released, so we need to clean up the queue and bug out
        // early.
        if (queuedBuffer) {
            Mutex::Autolock lock(mQueueItemLock);
            mQueueItems.clear();
            android_atomic_and(0, &mQueuedFrames);
        }

        // Once we have hit this state, the shadow queue may no longer
        // correctly reflect the incoming BufferQueue's contents, so even if
        // updateTexImage starts working, the only safe course of action is
        // to continue to ignore updates.
        mUpdateTexImageFailed = true;

        return outDirtyRegion;
    }

    if (queuedBuffer) {
        // Autolock scope
        auto currentFrameNumber = mSurfaceFlingerConsumer->getFrameNumber();

        Mutex::Autolock lock(mQueueItemLock);

        // Remove any stale buffers that have been dropped during
        // updateTexImage
        while (mQueueItems[0].mFrameNumber != currentFrameNumber) {
            mQueueItems.removeAt(0);
            android_atomic_dec(&mQueuedFrames);
        }

        mQueueItems.removeAt(0);
    }

    // Decrement the queued-frames count.  Signal another event if we
    // have more frames pending.
    if ((queuedBuffer && android_atomic_dec(&mQueuedFrames) > 1) || mAutoRefresh) {
        mFlinger->signalLayerUpdate();
    }

    // update the active buffer
    mActiveBuffer = mSurfaceFlingerConsumer->getCurrentBuffer(&mActiveBufferSlot);
    if (mActiveBuffer == NULL) {
        // this can only happen if the very first buffer was rejected.
        return outDirtyRegion;
    }

    mBufferLatched = true;
    mPreviousFrameNumber = mCurrentFrameNumber;
    mCurrentFrameNumber = mSurfaceFlingerConsumer->getFrameNumber();

    {
        Mutex::Autolock lock(mFrameEventHistoryMutex);
        mFrameEventHistory.addLatch(mCurrentFrameNumber, latchTime);
#ifndef USE_HWC2
        auto releaseFenceTime =
                std::make_shared<FenceTime>(mSurfaceFlingerConsumer->getPrevFinalReleaseFence());
        mReleaseTimeline.updateSignalTimes();
        mReleaseTimeline.push(releaseFenceTime);
        if (mPreviousFrameNumber != 0) {
            mFrameEventHistory.addRelease(mPreviousFrameNumber, latchTime,
                                          std::move(releaseFenceTime));
        }
#endif
    }

    mRefreshPending = true;
    mFrameLatencyNeeded = true;
    if (oldActiveBuffer == NULL) {
        // the first time we receive a buffer, we need to trigger a
        // geometry invalidation.
        recomputeVisibleRegions = true;
    }

    setDataSpace(mSurfaceFlingerConsumer->getCurrentDataSpace());

    Rect crop(mSurfaceFlingerConsumer->getCurrentCrop());
    const uint32_t transform(mSurfaceFlingerConsumer->getCurrentTransform());
    const uint32_t scalingMode(mSurfaceFlingerConsumer->getCurrentScalingMode());
    if ((crop != mCurrentCrop) || (transform != mCurrentTransform) ||
        (scalingMode != mCurrentScalingMode)) {
        mCurrentCrop = crop;
        mCurrentTransform = transform;
        mCurrentScalingMode = scalingMode;
        recomputeVisibleRegions = true;
    }

    if (oldActiveBuffer != NULL) {
        uint32_t bufWidth = mActiveBuffer->getWidth();
        uint32_t bufHeight = mActiveBuffer->getHeight();
        if (bufWidth != uint32_t(oldActiveBuffer->width) ||
            bufHeight != uint32_t(oldActiveBuffer->height)) {
            recomputeVisibleRegions = true;
        }
    }

    mCurrentOpacity = getOpacityForFormat(mActiveBuffer->format);
    if (oldOpacity != isOpaque(s)) {
        recomputeVisibleRegions = true;
    }

    // Remove any sync points corresponding to the buffer which was just
    // latched
    {
        Mutex::Autolock lock(mLocalSyncPointMutex);
        auto point = mLocalSyncPoints.begin();
        while (point != mLocalSyncPoints.end()) {
            if (!(*point)->frameIsAvailable() || !(*point)->transactionIsApplied()) {
                // This sync point must have been added since we started
                // latching. Don't drop it yet.
                ++point;
                continue;
            }

            if ((*point)->getFrameNumber() <= mCurrentFrameNumber) {
                point = mLocalSyncPoints.erase(point);
            } else {
                ++point;
            }
        }
    }

    // FIXME: postedRegion should be dirty & bounds
    Region dirtyRegion(Rect(s.active.w, s.active.h));

    // transform the dirty region to window-manager space
    outDirtyRegion = (getTransform().transform(dirtyRegion));

    return outDirtyRegion;
}

#ifdef USE_HWC2
void BufferLayer::setPerFrameData(const sp<const DisplayDevice>& displayDevice) {
    // Apply this display's projection's viewport to the visible region
    // before giving it to the HWC HAL.
    const Transform& tr = displayDevice->getTransform();
    const auto& viewport = displayDevice->getViewport();
    Region visible = tr.transform(visibleRegion.intersect(viewport));
    auto hwcId = displayDevice->getHwcDisplayId();
    auto& hwcInfo = mHwcLayers[hwcId];
    auto& hwcLayer = hwcInfo.layer;
    auto error = hwcLayer->setVisibleRegion(visible);
    if (error != HWC2::Error::None) {
        ALOGE("[%s] Failed to set visible region: %s (%d)", mName.string(),
              to_string(error).c_str(), static_cast<int32_t>(error));
        visible.dump(LOG_TAG);
    }

    error = hwcLayer->setSurfaceDamage(surfaceDamageRegion);
    if (error != HWC2::Error::None) {
        ALOGE("[%s] Failed to set surface damage: %s (%d)", mName.string(),
              to_string(error).c_str(), static_cast<int32_t>(error));
        surfaceDamageRegion.dump(LOG_TAG);
    }

    // Sideband layers
    if (mSidebandStream.get()) {
        setCompositionType(hwcId, HWC2::Composition::Sideband);
        ALOGV("[%s] Requesting Sideband composition", mName.string());
        error = hwcLayer->setSidebandStream(mSidebandStream->handle());
        if (error != HWC2::Error::None) {
            ALOGE("[%s] Failed to set sideband stream %p: %s (%d)", mName.string(),
                  mSidebandStream->handle(), to_string(error).c_str(), static_cast<int32_t>(error));
        }
        return;
    }

    // Client layers
    if (hwcInfo.forceClientComposition ||
        (mActiveBuffer != nullptr && mActiveBuffer->handle == nullptr)) {
        ALOGV("[%s] Requesting Client composition", mName.string());
        setCompositionType(hwcId, HWC2::Composition::Client);
        return;
    }

    // SolidColor layers
    if (mActiveBuffer == nullptr) {
        setCompositionType(hwcId, HWC2::Composition::SolidColor);

        // For now, we only support black for DimLayer
        error = hwcLayer->setColor({0, 0, 0, 255});
        if (error != HWC2::Error::None) {
            ALOGE("[%s] Failed to set color: %s (%d)", mName.string(), to_string(error).c_str(),
                  static_cast<int32_t>(error));
        }

        // Clear out the transform, because it doesn't make sense absent a
        // source buffer
        error = hwcLayer->setTransform(HWC2::Transform::None);
        if (error != HWC2::Error::None) {
            ALOGE("[%s] Failed to clear transform: %s (%d)", mName.string(),
                  to_string(error).c_str(), static_cast<int32_t>(error));
        }

        return;
    }

    // Device or Cursor layers
    if (mPotentialCursor) {
        ALOGV("[%s] Requesting Cursor composition", mName.string());
        setCompositionType(hwcId, HWC2::Composition::Cursor);
    } else {
        ALOGV("[%s] Requesting Device composition", mName.string());
        setCompositionType(hwcId, HWC2::Composition::Device);
    }

    ALOGV("setPerFrameData: dataspace = %d", mCurrentState.dataSpace);
    error = hwcLayer->setDataspace(mCurrentState.dataSpace);
    if (error != HWC2::Error::None) {
        ALOGE("[%s] Failed to set dataspace %d: %s (%d)", mName.string(), mCurrentState.dataSpace,
              to_string(error).c_str(), static_cast<int32_t>(error));
    }

    uint32_t hwcSlot = 0;
    sp<GraphicBuffer> hwcBuffer;
    hwcInfo.bufferCache.getHwcBuffer(mActiveBufferSlot, mActiveBuffer, &hwcSlot, &hwcBuffer);

    auto acquireFence = mSurfaceFlingerConsumer->getCurrentFence();
    error = hwcLayer->setBuffer(hwcSlot, hwcBuffer, acquireFence);
    if (error != HWC2::Error::None) {
        ALOGE("[%s] Failed to set buffer %p: %s (%d)", mName.string(), mActiveBuffer->handle,
              to_string(error).c_str(), static_cast<int32_t>(error));
    }
}

#else
void BufferLayer::setPerFrameData(const sp<const DisplayDevice>& hw,
                                  HWComposer::HWCLayerInterface& layer) {
    // we have to set the visible region on every frame because
    // we currently free it during onLayerDisplayed(), which is called
    // after HWComposer::commit() -- every frame.
    // Apply this display's projection's viewport to the visible region
    // before giving it to the HWC HAL.
    const Transform& tr = hw->getTransform();
    Region visible = tr.transform(visibleRegion.intersect(hw->getViewport()));
    layer.setVisibleRegionScreen(visible);
    layer.setSurfaceDamage(surfaceDamageRegion);
    mIsGlesComposition = (layer.getCompositionType() == HWC_FRAMEBUFFER);

    if (mSidebandStream.get()) {
        layer.setSidebandStream(mSidebandStream);
    } else {
        // NOTE: buffer can be NULL if the client never drew into this
        // layer yet, or if we ran out of memory
        layer.setBuffer(mActiveBuffer);
    }
}
#endif

bool BufferLayer::isOpaque(const Layer::State& s) const
{
    // if we don't have a buffer or sidebandStream yet, we're translucent regardless of the
    // layer's opaque flag.
    if ((mSidebandStream == nullptr) && (mActiveBuffer == nullptr)) {
        return false;
    }

    // if the layer has the opaque flag, then we're always opaque,
    // otherwise we use the current buffer's format.
    return ((s.flags & layer_state_t::eLayerOpaque) != 0) || mCurrentOpacity;
}

void BufferLayer::onFirstRef() {
    // Creates a custom BufferQueue for SurfaceFlingerConsumer to use
    sp<IGraphicBufferProducer> producer;
    sp<IGraphicBufferConsumer> consumer;
    BufferQueue::createBufferQueue(&producer, &consumer, true);
    mProducer = new MonitoredProducer(producer, mFlinger, this);
    mSurfaceFlingerConsumer = new SurfaceFlingerConsumer(consumer, mTextureName, this);
    mSurfaceFlingerConsumer->setConsumerUsageBits(getEffectiveUsage(0));
    mSurfaceFlingerConsumer->setContentsChangedListener(this);
    mSurfaceFlingerConsumer->setName(mName);

    if (mFlinger->isLayerTripleBufferingDisabled()) {
        mProducer->setMaxDequeuedBufferCount(2);
    }

    const sp<const DisplayDevice> hw(mFlinger->getDefaultDisplayDevice());
    updateTransformHint(hw);
}

// ---------------------------------------------------------------------------
// Interface implementation for SurfaceFlingerConsumer::ContentsChangedListener
// ---------------------------------------------------------------------------

void BufferLayer::onFrameAvailable(const BufferItem& item) {
    // Add this buffer from our internal queue tracker
    { // Autolock scope
        Mutex::Autolock lock(mQueueItemLock);
        mFlinger->mInterceptor.saveBufferUpdate(this, item.mGraphicBuffer->getWidth(),
                                                item.mGraphicBuffer->getHeight(),
                                                item.mFrameNumber);
        // Reset the frame number tracker when we receive the first buffer after
        // a frame number reset
        if (item.mFrameNumber == 1) {
            mLastFrameNumberReceived = 0;
        }

        // Ensure that callbacks are handled in order
        while (item.mFrameNumber != mLastFrameNumberReceived + 1) {
            status_t result = mQueueItemCondition.waitRelative(mQueueItemLock, ms2ns(500));
            if (result != NO_ERROR) {
                ALOGE("[%s] Timed out waiting on callback", mName.string());
            }
        }

        mQueueItems.push_back(item);
        android_atomic_inc(&mQueuedFrames);

        // Wake up any pending callbacks
        mLastFrameNumberReceived = item.mFrameNumber;
        mQueueItemCondition.broadcast();
    }

    mFlinger->signalLayerUpdate();
}

void BufferLayer::onFrameReplaced(const BufferItem& item) {
    { // Autolock scope
        Mutex::Autolock lock(mQueueItemLock);

        // Ensure that callbacks are handled in order
        while (item.mFrameNumber != mLastFrameNumberReceived + 1) {
            status_t result = mQueueItemCondition.waitRelative(mQueueItemLock, ms2ns(500));
            if (result != NO_ERROR) {
                ALOGE("[%s] Timed out waiting on callback", mName.string());
            }
        }

        if (mQueueItems.empty()) {
            ALOGE("Can't replace a frame on an empty queue");
            return;
        }
        mQueueItems.editItemAt(mQueueItems.size() - 1) = item;

        // Wake up any pending callbacks
        mLastFrameNumberReceived = item.mFrameNumber;
        mQueueItemCondition.broadcast();
    }
}

void BufferLayer::onSidebandStreamChanged() {
    if (android_atomic_release_cas(false, true, &mSidebandStreamChanged) == 0) {
        // mSidebandStreamChanged was false
        mFlinger->signalLayerUpdate();
    }
}

bool BufferLayer::needsFiltering(const RenderArea& renderArea) const {
    return mNeedsFiltering || renderArea.needsFiltering();
}

// As documented in libhardware header, formats in the range
// 0x100 - 0x1FF are specific to the HAL implementation, and
// are known to have no alpha channel
// TODO: move definition for device-specific range into
// hardware.h, instead of using hard-coded values here.
#define HARDWARE_IS_DEVICE_FORMAT(f) ((f) >= 0x100 && (f) <= 0x1FF)

bool BufferLayer::getOpacityForFormat(uint32_t format) {
    if (HARDWARE_IS_DEVICE_FORMAT(format)) {
        return true;
    }
    switch (format) {
        case HAL_PIXEL_FORMAT_RGBA_8888:
        case HAL_PIXEL_FORMAT_BGRA_8888:
        case HAL_PIXEL_FORMAT_RGBA_FP16:
        case HAL_PIXEL_FORMAT_RGBA_1010102:
            return false;
    }
    // in all other case, we have no blending (also for unknown formats)
    return true;
}

void BufferLayer::drawWithOpenGL(const RenderArea& renderArea, 
        bool useIdentityTransform) const {
    const State& s(getDrawingState());

    computeGeometry(renderArea, mMesh, useIdentityTransform);

    /*
     * NOTE: the way we compute the texture coordinates here produces
     * different results than when we take the HWC path -- in the later case
     * the "source crop" is rounded to texel boundaries.
     * This can produce significantly different results when the texture
     * is scaled by a large amount.
     *
     * The GL code below is more logical (imho), and the difference with
     * HWC is due to a limitation of the HWC API to integers -- a question
     * is suspend is whether we should ignore this problem or revert to
     * GL composition when a buffer scaling is applied (maybe with some
     * minimal value)? Or, we could make GL behave like HWC -- but this feel
     * like more of a hack.
     */
    Rect win(computeBounds());

    Transform t = getTransform();
    if (!s.finalCrop.isEmpty()) {
        win = t.transform(win);
        if (!win.intersect(s.finalCrop, &win)) {
            win.clear();
        }
        win = t.inverse().transform(win);
        if (!win.intersect(computeBounds(), &win)) {
            win.clear();
        }
    }

    float left = float(win.left) / float(s.active.w);
    float top = float(win.top) / float(s.active.h);
    float right = float(win.right) / float(s.active.w);
    float bottom = float(win.bottom) / float(s.active.h);

    // TODO: we probably want to generate the texture coords with the mesh
    // here we assume that we only have 4 vertices
    Mesh::VertexArray<vec2> texCoords(mMesh.getTexCoordArray<vec2>());
    texCoords[0] = vec2(left, 1.0f - top);
    texCoords[1] = vec2(left, 1.0f - bottom);
    texCoords[2] = vec2(right, 1.0f - bottom);
    texCoords[3] = vec2(right, 1.0f - top);

    RenderEngine& engine(mFlinger->getRenderEngine());
    engine.setupLayerBlending(mPremultipliedAlpha, isOpaque(s), false /* disableTexture */,
                              getColor());
#ifdef USE_HWC2
    engine.setSourceDataSpace(mCurrentState.dataSpace);
#endif
    engine.drawMesh(mMesh);
    engine.disableBlending();
}

uint32_t BufferLayer::getProducerStickyTransform() const {
    int producerStickyTransform = 0;
    int ret = mProducer->query(NATIVE_WINDOW_STICKY_TRANSFORM, &producerStickyTransform);
    if (ret != OK) {
        ALOGW("%s: Error %s (%d) while querying window sticky transform.", __FUNCTION__,
              strerror(-ret), ret);
        return 0;
    }
    return static_cast<uint32_t>(producerStickyTransform);
}

bool BufferLayer::latchUnsignaledBuffers() {
    static bool propertyLoaded = false;
    static bool latch = false;
    static std::mutex mutex;
    std::lock_guard<std::mutex> lock(mutex);
    if (!propertyLoaded) {
        char value[PROPERTY_VALUE_MAX] = {};
        property_get("debug.sf.latch_unsignaled", value, "0");
        latch = atoi(value);
        propertyLoaded = true;
    }
    return latch;
}

uint64_t BufferLayer::getHeadFrameNumber() const {
    Mutex::Autolock lock(mQueueItemLock);
    if (!mQueueItems.empty()) {
        return mQueueItems[0].mFrameNumber;
    } else {
        return mCurrentFrameNumber;
    }
}

bool BufferLayer::headFenceHasSignaled() const {
#ifdef USE_HWC2
    if (latchUnsignaledBuffers()) {
        return true;
    }

    Mutex::Autolock lock(mQueueItemLock);
    if (mQueueItems.empty()) {
        return true;
    }
    if (mQueueItems[0].mIsDroppable) {
        // Even though this buffer's fence may not have signaled yet, it could
        // be replaced by another buffer before it has a chance to, which means
        // that it's possible to get into a situation where a buffer is never
        // able to be latched. To avoid this, grab this buffer anyway.
        return true;
    }
    return mQueueItems[0].mFenceTime->getSignalTime() != Fence::SIGNAL_TIME_PENDING;
#else
    return true;
#endif
}

uint32_t BufferLayer::getEffectiveScalingMode() const {
    if (mOverrideScalingMode >= 0) {
        return mOverrideScalingMode;
    }
    return mCurrentScalingMode;
}

// ----------------------------------------------------------------------------
// transaction
// ----------------------------------------------------------------------------

void BufferLayer::notifyAvailableFrames() {
    auto headFrameNumber = getHeadFrameNumber();
    bool headFenceSignaled = headFenceHasSignaled();
    Mutex::Autolock lock(mLocalSyncPointMutex);
    for (auto& point : mLocalSyncPoints) {
        if (headFrameNumber >= point->getFrameNumber() && headFenceSignaled) {
            point->setFrameAvailable();
        }
    }
}

sp<IGraphicBufferProducer> BufferLayer::getProducer() const {
    return mProducer;
}

// ---------------------------------------------------------------------------
// h/w composer set-up
// ---------------------------------------------------------------------------

bool BufferLayer::allTransactionsSignaled() {
    auto headFrameNumber = getHeadFrameNumber();
    bool matchingFramesFound = false;
    bool allTransactionsApplied = true;
    Mutex::Autolock lock(mLocalSyncPointMutex);

    for (auto& point : mLocalSyncPoints) {
        if (point->getFrameNumber() > headFrameNumber) {
            break;
        }
        matchingFramesFound = true;

        if (!point->frameIsAvailable()) {
            // We haven't notified the remote layer that the frame for
            // this point is available yet. Notify it now, and then
            // abort this attempt to latch.
            point->setFrameAvailable();
            allTransactionsApplied = false;
            break;
        }

        allTransactionsApplied = allTransactionsApplied && point->transactionIsApplied();
    }
    return !matchingFramesFound || allTransactionsApplied;
}

} // 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