services/surfaceflinger/BufferStateLayer.cpp - android_frameworks_native - Gitiles

 /*
  * 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 "BufferStateLayer"
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS

 #include "BufferStateLayer.h"
 #include "ColorLayer.h"

 #include "TimeStats/TimeStats.h"

 #include <private/gui/SyncFeatures.h>
 #include <renderengine/Image.h>

 #include <limits>

 namespace android {

 // clang-format off
 const std::array<float, 16> BufferStateLayer::IDENTITY_MATRIX{
         1, 0, 0, 0,
         0, 1, 0, 0,
         0, 0, 1, 0,
         0, 0, 0, 1
 };
 // clang-format on

 BufferStateLayer::BufferStateLayer(const LayerCreationArgs& args) : BufferLayer(args) {
     mOverrideScalingMode = NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW;
     mCurrentState.dataspace = ui::Dataspace::V0_SRGB;
 }
 BufferStateLayer::~BufferStateLayer() = default;

 // -----------------------------------------------------------------------
 // Interface implementation for Layer
 // -----------------------------------------------------------------------
 void BufferStateLayer::onLayerDisplayed(const sp<Fence>& releaseFence) {
     // The previous release fence notifies the client that SurfaceFlinger is done with the previous
     // buffer that was presented on this layer. The first transaction that came in this frame that
     // replaced the previous buffer on this layer needs this release fence, because the fence will
     // let the client know when that previous buffer is removed from the screen.
     //
     // Every other transaction on this layer does not need a release fence because no other
     // Transactions that were set on this layer this frame are going to have their preceeding buffer
     // removed from the display this frame.
     //
     // For example, if we have 3 transactions this frame. The first transaction doesn't contain a
     // buffer so it doesn't need a previous release fence because the layer still needs the previous
     // buffer. The second transaction contains a buffer so it needs a previous release fence because
     // the previous buffer will be released this frame. The third transaction also contains a
     // buffer. It replaces the buffer in the second transaction. The buffer in the second
     // transaction will now no longer be presented so it is released immediately and the third
     // transaction doesn't need a previous release fence.
     for (auto& handle : mDrawingState.callbackHandles) {
         if (handle->releasePreviousBuffer) {
             handle->previousReleaseFence = releaseFence;
             break;
         }
     }
 }

 void BufferStateLayer::setTransformHint(uint32_t /*orientation*/) const {
     // TODO(marissaw): send the transform hint to buffer owner
     return;
 }

 void BufferStateLayer::releasePendingBuffer(nsecs_t /*dequeueReadyTime*/) {
     mFlinger->getTransactionCompletedThread().addPresentedCallbackHandles(
             mDrawingState.callbackHandles);

     mDrawingState.callbackHandles = {};
 }

 bool BufferStateLayer::shouldPresentNow(nsecs_t /*expectedPresentTime*/) const {
     if (getSidebandStreamChanged() || getAutoRefresh()) {
         return true;
     }

     return hasFrameUpdate();
 }

 bool BufferStateLayer::willPresentCurrentTransaction() const {
     // Returns true if the most recent Transaction applied to CurrentState will be presented.
     return getSidebandStreamChanged() || getAutoRefresh() ||
             (mCurrentState.modified &&
              (mCurrentState.buffer != nullptr || mCurrentState.bgColorLayer != nullptr));
 }

 bool BufferStateLayer::getTransformToDisplayInverse() const {
     return mCurrentState.transformToDisplayInverse;
 }

 void BufferStateLayer::pushPendingState() {
     if (!mCurrentState.modified) {
         return;
     }
     mPendingStates.push_back(mCurrentState);
     ATRACE_INT(mTransactionName.string(), mPendingStates.size());
 }

 bool BufferStateLayer::applyPendingStates(Layer::State* stateToCommit) {
     const bool stateUpdateAvailable = !mPendingStates.empty();
     while (!mPendingStates.empty()) {
         popPendingState(stateToCommit);
     }
     mCurrentStateModified = stateUpdateAvailable && mCurrentState.modified;
     mCurrentState.modified = false;
     return stateUpdateAvailable;
 }

 // Crop that applies to the window
 Rect BufferStateLayer::getCrop(const Layer::State& /*s*/) const {
     return Rect::INVALID_RECT;
 }

 bool BufferStateLayer::setTransform(uint32_t transform) {
     if (mCurrentState.transform == transform) return false;
     mCurrentState.sequence++;
     mCurrentState.transform = transform;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setTransformToDisplayInverse(bool transformToDisplayInverse) {
     if (mCurrentState.transformToDisplayInverse == transformToDisplayInverse) return false;
     mCurrentState.sequence++;
     mCurrentState.transformToDisplayInverse = transformToDisplayInverse;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setCrop(const Rect& crop) {
     if (mCurrentState.crop == crop) return false;
     mCurrentState.sequence++;
     mCurrentState.crop = crop;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setFrame(const Rect& frame) {
     int x = frame.left;
     int y = frame.top;
     int w = frame.getWidth();
     int h = frame.getHeight();

     if (x < 0) {
         x = 0;
         w = frame.right;
     }

     if (y < 0) {
         y = 0;
         h = frame.bottom;
     }

     if (mCurrentState.active.transform.tx() == x && mCurrentState.active.transform.ty() == y &&
         mCurrentState.active.w == w && mCurrentState.active.h == h) {
         return false;
     }

     if (!frame.isValid()) {
         x = y = w = h = 0;
     }
     mCurrentState.active.transform.set(x, y);
     mCurrentState.active.w = w;
     mCurrentState.active.h = h;

     mCurrentState.sequence++;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setBuffer(const sp<GraphicBuffer>& buffer) {
     if (mCurrentState.buffer) {
         mReleasePreviousBuffer = true;
     }

     mCurrentState.sequence++;
     mCurrentState.buffer = buffer;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setAcquireFence(const sp<Fence>& fence) {
     // The acquire fences of BufferStateLayers have already signaled before they are set
     mCallbackHandleAcquireTime = fence->getSignalTime();

     mCurrentState.acquireFence = fence;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setDataspace(ui::Dataspace dataspace) {
     if (mCurrentState.dataspace == dataspace) return false;
     mCurrentState.sequence++;
     mCurrentState.dataspace = dataspace;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setHdrMetadata(const HdrMetadata& hdrMetadata) {
     if (mCurrentState.hdrMetadata == hdrMetadata) return false;
     mCurrentState.sequence++;
     mCurrentState.hdrMetadata = hdrMetadata;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setSurfaceDamageRegion(const Region& surfaceDamage) {
     mCurrentState.sequence++;
     mCurrentState.surfaceDamageRegion = surfaceDamage;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setApi(int32_t api) {
     if (mCurrentState.api == api) return false;
     mCurrentState.sequence++;
     mCurrentState.api = api;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 bool BufferStateLayer::setSidebandStream(const sp<NativeHandle>& sidebandStream) {
     if (mCurrentState.sidebandStream == sidebandStream) return false;
     mCurrentState.sequence++;
     mCurrentState.sidebandStream = sidebandStream;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);

     if (!mSidebandStreamChanged.exchange(true)) {
         // mSidebandStreamChanged was false
         mFlinger->signalLayerUpdate();
     }
     return true;
 }

 bool BufferStateLayer::setTransactionCompletedListeners(
         const std::vector<sp<CallbackHandle>>& handles) {
     // If there is no handle, we will not send a callback so reset mReleasePreviousBuffer and return
     if (handles.empty()) {
         mReleasePreviousBuffer = false;
         return false;
     }

     const bool willPresent = willPresentCurrentTransaction();

     for (const auto& handle : handles) {
         // If this transaction set a buffer on this layer, release its previous buffer
         handle->releasePreviousBuffer = mReleasePreviousBuffer;

         // If this layer will be presented in this frame
         if (willPresent) {
             // If this transaction set an acquire fence on this layer, set its acquire time
             handle->acquireTime = mCallbackHandleAcquireTime;

             // Notify the transaction completed thread that there is a pending latched callback
             // handle
             mFlinger->getTransactionCompletedThread().registerPendingCallbackHandle(handle);

             // Store so latched time and release fence can be set
             mCurrentState.callbackHandles.push_back(handle);

         } else { // If this layer will NOT need to be relatched and presented this frame
             // Notify the transaction completed thread this handle is done
             mFlinger->getTransactionCompletedThread().addUnpresentedCallbackHandle(handle);
         }
     }

     mReleasePreviousBuffer = false;
     mCallbackHandleAcquireTime = -1;

     return willPresent;
 }

 bool BufferStateLayer::setTransparentRegionHint(const Region& transparent) {
     mCurrentState.transparentRegionHint = transparent;
     mCurrentState.modified = true;
     setTransactionFlags(eTransactionNeeded);
     return true;
 }

 Rect BufferStateLayer::getBufferSize(const State& s) const {
     // for buffer state layers we use the display frame size as the buffer size.
     if (getActiveWidth(s) < UINT32_MAX && getActiveHeight(s) < UINT32_MAX) {
         return Rect(getActiveWidth(s), getActiveHeight(s));
     }

     // if the display frame is not defined, use the parent bounds as the buffer size.
     const auto& p = mDrawingParent.promote();
     if (p != nullptr) {
         Rect parentBounds = Rect(p->getBounds(Region()));
         if (!parentBounds.isEmpty()) {
             return parentBounds;
         }
     }

     // if there is no parent layer, use the buffer's bounds as the buffer size
     if (s.buffer) {
         return s.buffer->getBounds();
     }
     return Rect::INVALID_RECT;
 }

 FloatRect BufferStateLayer::computeSourceBounds(const FloatRect& parentBounds) const {
     const State& s(getDrawingState());
     // for buffer state layers we use the display frame size as the buffer size.
     if (getActiveWidth(s) < UINT32_MAX && getActiveHeight(s) < UINT32_MAX) {
         return FloatRect(0, 0, getActiveWidth(s), getActiveHeight(s));
     }

     // if the display frame is not defined, use the parent bounds as the buffer size.
     return parentBounds;
 }

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

 // -----------------------------------------------------------------------
 // Interface implementation for BufferLayer
 // -----------------------------------------------------------------------
 bool BufferStateLayer::fenceHasSignaled() const {
     if (latchUnsignaledBuffers()) {
         return true;
     }

     return getDrawingState().acquireFence->getStatus() == Fence::Status::Signaled;
 }

 nsecs_t BufferStateLayer::getDesiredPresentTime() {
     // TODO(marissaw): support an equivalent to desiredPresentTime for timestats metrics
     return 0;
 }

 std::shared_ptr<FenceTime> BufferStateLayer::getCurrentFenceTime() const {
     return std::make_shared<FenceTime>(getDrawingState().acquireFence);
 }

 void BufferStateLayer::getDrawingTransformMatrix(float *matrix) {
     std::copy(std::begin(mTransformMatrix), std::end(mTransformMatrix), matrix);
 }

 uint32_t BufferStateLayer::getDrawingTransform() const {
     return getDrawingState().transform;
 }

 ui::Dataspace BufferStateLayer::getDrawingDataSpace() const {
     return getDrawingState().dataspace;
 }

 // Crop that applies to the buffer
 Rect BufferStateLayer::getDrawingCrop() const {
     const State& s(getDrawingState());

     if (s.crop.isEmpty() && s.buffer) {
         return s.buffer->getBounds();
     } else if (s.buffer) {
         Rect crop = s.crop;
         crop.left = std::max(crop.left, 0);
         crop.top = std::max(crop.top, 0);
         uint32_t bufferWidth = s.buffer->getWidth();
         uint32_t bufferHeight = s.buffer->getHeight();
         if (bufferHeight <= std::numeric_limits<int32_t>::max() &&
             bufferWidth <= std::numeric_limits<int32_t>::max()) {
             crop.right = std::min(crop.right, static_cast<int32_t>(bufferWidth));
             crop.bottom = std::min(crop.bottom, static_cast<int32_t>(bufferHeight));
         }
         if (!crop.isValid()) {
             // Crop rect is out of bounds, return whole buffer
             return s.buffer->getBounds();
         }
         return crop;
     }
     return s.crop;
 }

 uint32_t BufferStateLayer::getDrawingScalingMode() const {
     return NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW;
 }

 Region BufferStateLayer::getDrawingSurfaceDamage() const {
     return getDrawingState().surfaceDamageRegion;
 }

 const HdrMetadata& BufferStateLayer::getDrawingHdrMetadata() const {
     return getDrawingState().hdrMetadata;
 }

 int BufferStateLayer::getDrawingApi() const {
     return getDrawingState().api;
 }

 PixelFormat BufferStateLayer::getPixelFormat() const {
     if (!mActiveBuffer) {
         return PIXEL_FORMAT_NONE;
     }
     return mActiveBuffer->format;
 }

 uint64_t BufferStateLayer::getFrameNumber() const {
     return mFrameNumber;
 }

 bool BufferStateLayer::getAutoRefresh() const {
     // TODO(marissaw): support shared buffer mode
     return false;
 }

 bool BufferStateLayer::getSidebandStreamChanged() const {
     return mSidebandStreamChanged.load();
 }

 bool BufferStateLayer::latchSidebandStream(bool& recomputeVisibleRegions) {
     if (mSidebandStreamChanged.exchange(false)) {
         const State& s(getDrawingState());
         // mSidebandStreamChanged was true
         // replicated in LayerBE until FE/BE is ready to be synchronized
         getBE().compositionInfo.hwc.sidebandStream = s.sidebandStream;
         if (getBE().compositionInfo.hwc.sidebandStream != nullptr) {
             setTransactionFlags(eTransactionNeeded);
             mFlinger->setTransactionFlags(eTraversalNeeded);
         }
         recomputeVisibleRegions = true;

         return true;
     }
     return false;
 }

 bool BufferStateLayer::hasFrameUpdate() const {
     const State& c(getCurrentState());
     return mCurrentStateModified && (c.buffer != nullptr || c.bgColorLayer != nullptr);
 }

 void BufferStateLayer::setFilteringEnabled(bool enabled) {
     GLConsumer::computeTransformMatrix(mTransformMatrix.data(), mActiveBuffer, mCurrentCrop,
                                        mCurrentTransform, enabled);
 }

 status_t BufferStateLayer::bindTextureImage() {
     const State& s(getDrawingState());
     auto& engine(mFlinger->getRenderEngine());

     return engine.bindExternalTextureBuffer(mTextureName, s.buffer, s.acquireFence, false);
 }

 status_t BufferStateLayer::updateTexImage(bool& /*recomputeVisibleRegions*/, nsecs_t latchTime,
                                           const sp<Fence>& releaseFence) {
     const State& s(getDrawingState());

     if (!s.buffer) {
         if (s.bgColorLayer) {
             for (auto& handle : mDrawingState.callbackHandles) {
                 handle->latchTime = latchTime;
             }
         }
         return NO_ERROR;
     }

     const int32_t layerID = getSequence();

     // Reject if the layer is invalid
     uint32_t bufferWidth = s.buffer->width;
     uint32_t bufferHeight = s.buffer->height;

     if (s.transform & ui::Transform::ROT_90) {
         std::swap(bufferWidth, bufferHeight);
     }

     if (s.transformToDisplayInverse) {
         uint32_t invTransform = DisplayDevice::getPrimaryDisplayOrientationTransform();
         if (invTransform & ui::Transform::ROT_90) {
             std::swap(bufferWidth, bufferHeight);
         }
     }

     if (getEffectiveScalingMode() == NATIVE_WINDOW_SCALING_MODE_FREEZE &&
         (s.active.w != bufferWidth || s.active.h != bufferHeight)) {
         ALOGE("[%s] rejecting buffer: "
               "bufferWidth=%d, bufferHeight=%d, front.active.{w=%d, h=%d}",
               mName.string(), bufferWidth, bufferHeight, s.active.w, s.active.h);
         mFlinger->mTimeStats->removeTimeRecord(layerID, getFrameNumber());
         return BAD_VALUE;
     }

     for (auto& handle : mDrawingState.callbackHandles) {
         handle->latchTime = latchTime;
     }

     // Handle sync fences
     if (SyncFeatures::getInstance().useNativeFenceSync() && releaseFence != Fence::NO_FENCE) {
         // TODO(alecmouri): Fail somewhere upstream if the fence is invalid.
         if (!releaseFence->isValid()) {
             mFlinger->mTimeStats->onDestroy(layerID);
             return UNKNOWN_ERROR;
         }

         // Check status of fences first because merging is expensive.
         // Merging an invalid fence with any other fence results in an
         // invalid fence.
         auto currentStatus = s.acquireFence->getStatus();
         if (currentStatus == Fence::Status::Invalid) {
             ALOGE("Existing fence has invalid state");
             mFlinger->mTimeStats->onDestroy(layerID);
             return BAD_VALUE;
         }

         auto incomingStatus = releaseFence->getStatus();
         if (incomingStatus == Fence::Status::Invalid) {
             ALOGE("New fence has invalid state");
             mDrawingState.acquireFence = releaseFence;
             mFlinger->mTimeStats->onDestroy(layerID);
             return BAD_VALUE;
         }

         // If both fences are signaled or both are unsignaled, we need to merge
         // them to get an accurate timestamp.
         if (currentStatus == incomingStatus) {
             char fenceName[32] = {};
             snprintf(fenceName, 32, "%.28s:%d", mName.string(), mFrameNumber);
             sp<Fence> mergedFence =
                     Fence::merge(fenceName, mDrawingState.acquireFence, releaseFence);
             if (!mergedFence.get()) {
                 ALOGE("failed to merge release fences");
                 // synchronization is broken, the best we can do is hope fences
                 // signal in order so the new fence will act like a union
                 mDrawingState.acquireFence = releaseFence;
                 mFlinger->mTimeStats->onDestroy(layerID);
                 return BAD_VALUE;
             }
             mDrawingState.acquireFence = mergedFence;
         } else if (incomingStatus == Fence::Status::Unsignaled) {
             // If one fence has signaled and the other hasn't, the unsignaled
             // fence will approximately correspond with the correct timestamp.
             // There's a small race if both fences signal at about the same time
             // and their statuses are retrieved with unfortunate timing. However,
             // by this point, they will have both signaled and only the timestamp
             // will be slightly off; any dependencies after this point will
             // already have been met.
             mDrawingState.acquireFence = releaseFence;
         }
     } else {
         // Bind the new buffer to the GL texture.
         //
         // Older devices require the "implicit" synchronization provided
         // by glEGLImageTargetTexture2DOES, which this method calls.  Newer
         // devices will either call this in Layer::onDraw, or (if it's not
         // a GL-composited layer) not at all.
         status_t err = bindTextureImage();
         if (err != NO_ERROR) {
             mFlinger->mTimeStats->onDestroy(layerID);
             return BAD_VALUE;
         }
     }

     // TODO(marissaw): properly support mTimeStats
     mFlinger->mTimeStats->setPostTime(layerID, getFrameNumber(), getName().c_str(), latchTime);
     mFlinger->mTimeStats->setAcquireFence(layerID, getFrameNumber(), getCurrentFenceTime());
     mFlinger->mTimeStats->setLatchTime(layerID, getFrameNumber(), latchTime);

     return NO_ERROR;
 }

 status_t BufferStateLayer::updateActiveBuffer() {
     const State& s(getDrawingState());

     if (s.buffer == nullptr) {
         return BAD_VALUE;
     }

     mActiveBuffer = s.buffer;
     mActiveBufferFence = s.acquireFence;
     getBE().compositionInfo.mBuffer = mActiveBuffer;
     getBE().compositionInfo.mBufferSlot = 0;

     return NO_ERROR;
 }

 bool BufferStateLayer::useCachedBufferForClientComposition() const {
     // TODO: Store a proper staleness bit to support EGLImage caching.
     return false;
 }

 status_t BufferStateLayer::updateFrameNumber(nsecs_t /*latchTime*/) {
     // TODO(marissaw): support frame history events
     mCurrentFrameNumber = mFrameNumber;
     return NO_ERROR;
 }

 void BufferStateLayer::setHwcLayerBuffer(DisplayId displayId) {
     auto& hwcInfo = getBE().mHwcLayers[displayId];
     auto& hwcLayer = hwcInfo.layer;

     const State& s(getDrawingState());

     // TODO(marissaw): support more than one slot
     uint32_t hwcSlot = 0;

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

     mCurrentStateModified = false;
     mFrameNumber++;
 }

 void BufferStateLayer::onFirstRef() {
     BufferLayer::onFirstRef();

     if (const auto display = mFlinger->getDefaultDisplayDevice()) {
         updateTransformHint(display);
     }
 }

 } // namespace android
	/*
	* 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 "BufferStateLayer"
	#define ATRACE_TAG ATRACE_TAG_GRAPHICS

	#include "BufferStateLayer.h"
	#include "ColorLayer.h"

	#include "TimeStats/TimeStats.h"

	#include <private/gui/SyncFeatures.h>
	#include <renderengine/Image.h>

	#include <limits>

	namespace android {

	// clang-format off
	const std::array<float, 16> BufferStateLayer::IDENTITY_MATRIX{
	1, 0, 0, 0,
	0, 1, 0, 0,
	0, 0, 1, 0,
	0, 0, 0, 1
	};
	// clang-format on

	BufferStateLayer::BufferStateLayer(const LayerCreationArgs& args) : BufferLayer(args) {
	mOverrideScalingMode = NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW;
	mCurrentState.dataspace = ui::Dataspace::V0_SRGB;
	}
	BufferStateLayer::~BufferStateLayer() = default;

	// -----------------------------------------------------------------------
	// Interface implementation for Layer
	// -----------------------------------------------------------------------
	void BufferStateLayer::onLayerDisplayed(const sp<Fence>& releaseFence) {
	// The previous release fence notifies the client that SurfaceFlinger is done with the previous
	// buffer that was presented on this layer. The first transaction that came in this frame that
	// replaced the previous buffer on this layer needs this release fence, because the fence will
	// let the client know when that previous buffer is removed from the screen.
	//
	// Every other transaction on this layer does not need a release fence because no other
	// Transactions that were set on this layer this frame are going to have their preceeding buffer
	// removed from the display this frame.
	//
	// For example, if we have 3 transactions this frame. The first transaction doesn't contain a
	// buffer so it doesn't need a previous release fence because the layer still needs the previous
	// buffer. The second transaction contains a buffer so it needs a previous release fence because
	// the previous buffer will be released this frame. The third transaction also contains a
	// buffer. It replaces the buffer in the second transaction. The buffer in the second
	// transaction will now no longer be presented so it is released immediately and the third
	// transaction doesn't need a previous release fence.
	for (auto& handle : mDrawingState.callbackHandles) {
	if (handle->releasePreviousBuffer) {
	handle->previousReleaseFence = releaseFence;
	break;
	}
	}
	}

	void BufferStateLayer::setTransformHint(uint32_t /orientation/) const {
	// TODO(marissaw): send the transform hint to buffer owner
	return;
	}

	void BufferStateLayer::releasePendingBuffer(nsecs_t /dequeueReadyTime/) {
	mFlinger->getTransactionCompletedThread().addPresentedCallbackHandles(
	mDrawingState.callbackHandles);

	mDrawingState.callbackHandles = {};
	}

	bool BufferStateLayer::shouldPresentNow(nsecs_t /expectedPresentTime/) const {
	if (getSidebandStreamChanged() \|\| getAutoRefresh()) {
	return true;
	}

	return hasFrameUpdate();
	}

	bool BufferStateLayer::willPresentCurrentTransaction() const {
	// Returns true if the most recent Transaction applied to CurrentState will be presented.
	return getSidebandStreamChanged() \|\| getAutoRefresh() \|\|
	(mCurrentState.modified &&
	(mCurrentState.buffer != nullptr \|\| mCurrentState.bgColorLayer != nullptr));
	}

	bool BufferStateLayer::getTransformToDisplayInverse() const {
	return mCurrentState.transformToDisplayInverse;
	}

	void BufferStateLayer::pushPendingState() {
	if (!mCurrentState.modified) {
	return;
	}
	mPendingStates.push_back(mCurrentState);
	ATRACE_INT(mTransactionName.string(), mPendingStates.size());
	}

	bool BufferStateLayer::applyPendingStates(Layer::State* stateToCommit) {
	const bool stateUpdateAvailable = !mPendingStates.empty();
	while (!mPendingStates.empty()) {
	popPendingState(stateToCommit);
	}
	mCurrentStateModified = stateUpdateAvailable && mCurrentState.modified;
	mCurrentState.modified = false;
	return stateUpdateAvailable;
	}

	// Crop that applies to the window
	Rect BufferStateLayer::getCrop(const Layer::State& /s/) const {
	return Rect::INVALID_RECT;
	}

	bool BufferStateLayer::setTransform(uint32_t transform) {
	if (mCurrentState.transform == transform) return false;
	mCurrentState.sequence++;
	mCurrentState.transform = transform;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setTransformToDisplayInverse(bool transformToDisplayInverse) {
	if (mCurrentState.transformToDisplayInverse == transformToDisplayInverse) return false;
	mCurrentState.sequence++;
	mCurrentState.transformToDisplayInverse = transformToDisplayInverse;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setCrop(const Rect& crop) {
	if (mCurrentState.crop == crop) return false;
	mCurrentState.sequence++;
	mCurrentState.crop = crop;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setFrame(const Rect& frame) {
	int x = frame.left;
	int y = frame.top;
	int w = frame.getWidth();
	int h = frame.getHeight();

	if (x < 0) {
	x = 0;
	w = frame.right;
	}

	if (y < 0) {
	y = 0;
	h = frame.bottom;
	}

	if (mCurrentState.active.transform.tx() == x && mCurrentState.active.transform.ty() == y &&
	mCurrentState.active.w == w && mCurrentState.active.h == h) {
	return false;
	}

	if (!frame.isValid()) {
	x = y = w = h = 0;
	}
	mCurrentState.active.transform.set(x, y);
	mCurrentState.active.w = w;
	mCurrentState.active.h = h;

	mCurrentState.sequence++;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setBuffer(const sp<GraphicBuffer>& buffer) {
	if (mCurrentState.buffer) {
	mReleasePreviousBuffer = true;
	}

	mCurrentState.sequence++;
	mCurrentState.buffer = buffer;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setAcquireFence(const sp<Fence>& fence) {
	// The acquire fences of BufferStateLayers have already signaled before they are set
	mCallbackHandleAcquireTime = fence->getSignalTime();

	mCurrentState.acquireFence = fence;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setDataspace(ui::Dataspace dataspace) {
	if (mCurrentState.dataspace == dataspace) return false;
	mCurrentState.sequence++;
	mCurrentState.dataspace = dataspace;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setHdrMetadata(const HdrMetadata& hdrMetadata) {
	if (mCurrentState.hdrMetadata == hdrMetadata) return false;
	mCurrentState.sequence++;
	mCurrentState.hdrMetadata = hdrMetadata;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setSurfaceDamageRegion(const Region& surfaceDamage) {
	mCurrentState.sequence++;
	mCurrentState.surfaceDamageRegion = surfaceDamage;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setApi(int32_t api) {
	if (mCurrentState.api == api) return false;
	mCurrentState.sequence++;
	mCurrentState.api = api;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	bool BufferStateLayer::setSidebandStream(const sp<NativeHandle>& sidebandStream) {
	if (mCurrentState.sidebandStream == sidebandStream) return false;
	mCurrentState.sequence++;
	mCurrentState.sidebandStream = sidebandStream;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);

	if (!mSidebandStreamChanged.exchange(true)) {
	// mSidebandStreamChanged was false
	mFlinger->signalLayerUpdate();
	}
	return true;
	}

	bool BufferStateLayer::setTransactionCompletedListeners(
	const std::vector<sp<CallbackHandle>>& handles) {
	// If there is no handle, we will not send a callback so reset mReleasePreviousBuffer and return
	if (handles.empty()) {
	mReleasePreviousBuffer = false;
	return false;
	}

	const bool willPresent = willPresentCurrentTransaction();

	for (const auto& handle : handles) {
	// If this transaction set a buffer on this layer, release its previous buffer
	handle->releasePreviousBuffer = mReleasePreviousBuffer;

	// If this layer will be presented in this frame
	if (willPresent) {
	// If this transaction set an acquire fence on this layer, set its acquire time
	handle->acquireTime = mCallbackHandleAcquireTime;

	// Notify the transaction completed thread that there is a pending latched callback
	// handle
	mFlinger->getTransactionCompletedThread().registerPendingCallbackHandle(handle);

	// Store so latched time and release fence can be set
	mCurrentState.callbackHandles.push_back(handle);

	} else { // If this layer will NOT need to be relatched and presented this frame
	// Notify the transaction completed thread this handle is done
	mFlinger->getTransactionCompletedThread().addUnpresentedCallbackHandle(handle);
	}
	}

	mReleasePreviousBuffer = false;
	mCallbackHandleAcquireTime = -1;

	return willPresent;
	}

	bool BufferStateLayer::setTransparentRegionHint(const Region& transparent) {
	mCurrentState.transparentRegionHint = transparent;
	mCurrentState.modified = true;
	setTransactionFlags(eTransactionNeeded);
	return true;
	}

	Rect BufferStateLayer::getBufferSize(const State& s) const {
	// for buffer state layers we use the display frame size as the buffer size.
	if (getActiveWidth(s) < UINT32_MAX && getActiveHeight(s) < UINT32_MAX) {
	return Rect(getActiveWidth(s), getActiveHeight(s));
	}

	// if the display frame is not defined, use the parent bounds as the buffer size.
	const auto& p = mDrawingParent.promote();
	if (p != nullptr) {
	Rect parentBounds = Rect(p->getBounds(Region()));
	if (!parentBounds.isEmpty()) {
	return parentBounds;
	}
	}

	// if there is no parent layer, use the buffer's bounds as the buffer size
	if (s.buffer) {
	return s.buffer->getBounds();
	}
	return Rect::INVALID_RECT;
	}

	FloatRect BufferStateLayer::computeSourceBounds(const FloatRect& parentBounds) const {
	const State& s(getDrawingState());
	// for buffer state layers we use the display frame size as the buffer size.
	if (getActiveWidth(s) < UINT32_MAX && getActiveHeight(s) < UINT32_MAX) {
	return FloatRect(0, 0, getActiveWidth(s), getActiveHeight(s));
	}

	// if the display frame is not defined, use the parent bounds as the buffer size.
	return parentBounds;
	}

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

	// -----------------------------------------------------------------------
	// Interface implementation for BufferLayer
	// -----------------------------------------------------------------------
	bool BufferStateLayer::fenceHasSignaled() const {
	if (latchUnsignaledBuffers()) {
	return true;
	}

	return getDrawingState().acquireFence->getStatus() == Fence::Status::Signaled;
	}

	nsecs_t BufferStateLayer::getDesiredPresentTime() {
	// TODO(marissaw): support an equivalent to desiredPresentTime for timestats metrics
	return 0;
	}

	std::shared_ptr<FenceTime> BufferStateLayer::getCurrentFenceTime() const {
	return std::make_shared<FenceTime>(getDrawingState().acquireFence);
	}

	void BufferStateLayer::getDrawingTransformMatrix(float *matrix) {
	std::copy(std::begin(mTransformMatrix), std::end(mTransformMatrix), matrix);
	}

	uint32_t BufferStateLayer::getDrawingTransform() const {
	return getDrawingState().transform;
	}

	ui::Dataspace BufferStateLayer::getDrawingDataSpace() const {
	return getDrawingState().dataspace;
	}

	// Crop that applies to the buffer
	Rect BufferStateLayer::getDrawingCrop() const {
	const State& s(getDrawingState());

	if (s.crop.isEmpty() && s.buffer) {
	return s.buffer->getBounds();
	} else if (s.buffer) {
	Rect crop = s.crop;
	crop.left = std::max(crop.left, 0);
	crop.top = std::max(crop.top, 0);
	uint32_t bufferWidth = s.buffer->getWidth();
	uint32_t bufferHeight = s.buffer->getHeight();
	if (bufferHeight <= std::numeric_limits<int32_t>::max() &&
	bufferWidth <= std::numeric_limits<int32_t>::max()) {
	crop.right = std::min(crop.right, static_cast<int32_t>(bufferWidth));
	crop.bottom = std::min(crop.bottom, static_cast<int32_t>(bufferHeight));
	}
	if (!crop.isValid()) {
	// Crop rect is out of bounds, return whole buffer
	return s.buffer->getBounds();
	}
	return crop;
	}
	return s.crop;
	}

	uint32_t BufferStateLayer::getDrawingScalingMode() const {
	return NATIVE_WINDOW_SCALING_MODE_SCALE_TO_WINDOW;
	}

	Region BufferStateLayer::getDrawingSurfaceDamage() const {
	return getDrawingState().surfaceDamageRegion;
	}

	const HdrMetadata& BufferStateLayer::getDrawingHdrMetadata() const {
	return getDrawingState().hdrMetadata;
	}

	int BufferStateLayer::getDrawingApi() const {
	return getDrawingState().api;
	}

	PixelFormat BufferStateLayer::getPixelFormat() const {
	if (!mActiveBuffer) {
	return PIXEL_FORMAT_NONE;
	}
	return mActiveBuffer->format;
	}

	uint64_t BufferStateLayer::getFrameNumber() const {
	return mFrameNumber;
	}

	bool BufferStateLayer::getAutoRefresh() const {
	// TODO(marissaw): support shared buffer mode
	return false;
	}

	bool BufferStateLayer::getSidebandStreamChanged() const {
	return mSidebandStreamChanged.load();
	}

	bool BufferStateLayer::latchSidebandStream(bool& recomputeVisibleRegions) {
	if (mSidebandStreamChanged.exchange(false)) {
	const State& s(getDrawingState());
	// mSidebandStreamChanged was true
	// replicated in LayerBE until FE/BE is ready to be synchronized
	getBE().compositionInfo.hwc.sidebandStream = s.sidebandStream;
	if (getBE().compositionInfo.hwc.sidebandStream != nullptr) {
	setTransactionFlags(eTransactionNeeded);
	mFlinger->setTransactionFlags(eTraversalNeeded);
	}
	recomputeVisibleRegions = true;

	return true;
	}
	return false;
	}

	bool BufferStateLayer::hasFrameUpdate() const {
	const State& c(getCurrentState());
	return mCurrentStateModified && (c.buffer != nullptr \|\| c.bgColorLayer != nullptr);
	}

	void BufferStateLayer::setFilteringEnabled(bool enabled) {
	GLConsumer::computeTransformMatrix(mTransformMatrix.data(), mActiveBuffer, mCurrentCrop,
	mCurrentTransform, enabled);
	}

	status_t BufferStateLayer::bindTextureImage() {
	const State& s(getDrawingState());
	auto& engine(mFlinger->getRenderEngine());

	return engine.bindExternalTextureBuffer(mTextureName, s.buffer, s.acquireFence, false);
	}

	status_t BufferStateLayer::updateTexImage(bool& /recomputeVisibleRegions/, nsecs_t latchTime,
	const sp<Fence>& releaseFence) {
	const State& s(getDrawingState());

	if (!s.buffer) {
	if (s.bgColorLayer) {
	for (auto& handle : mDrawingState.callbackHandles) {
	handle->latchTime = latchTime;
	}
	}
	return NO_ERROR;
	}

	const int32_t layerID = getSequence();

	// Reject if the layer is invalid
	uint32_t bufferWidth = s.buffer->width;
	uint32_t bufferHeight = s.buffer->height;

	if (s.transform & ui::Transform::ROT_90) {
	std::swap(bufferWidth, bufferHeight);
	}

	if (s.transformToDisplayInverse) {
	uint32_t invTransform = DisplayDevice::getPrimaryDisplayOrientationTransform();
	if (invTransform & ui::Transform::ROT_90) {
	std::swap(bufferWidth, bufferHeight);
	}
	}

	if (getEffectiveScalingMode() == NATIVE_WINDOW_SCALING_MODE_FREEZE &&
	(s.active.w != bufferWidth \|\| s.active.h != bufferHeight)) {
	ALOGE("[%s] rejecting buffer: "
	"bufferWidth=%d, bufferHeight=%d, front.active.{w=%d, h=%d}",
	mName.string(), bufferWidth, bufferHeight, s.active.w, s.active.h);
	mFlinger->mTimeStats->removeTimeRecord(layerID, getFrameNumber());
	return BAD_VALUE;
	}

	for (auto& handle : mDrawingState.callbackHandles) {
	handle->latchTime = latchTime;
	}

	// Handle sync fences
	if (SyncFeatures::getInstance().useNativeFenceSync() && releaseFence != Fence::NO_FENCE) {
	// TODO(alecmouri): Fail somewhere upstream if the fence is invalid.
	if (!releaseFence->isValid()) {
	mFlinger->mTimeStats->onDestroy(layerID);
	return UNKNOWN_ERROR;
	}

	// Check status of fences first because merging is expensive.
	// Merging an invalid fence with any other fence results in an
	// invalid fence.
	auto currentStatus = s.acquireFence->getStatus();
	if (currentStatus == Fence::Status::Invalid) {
	ALOGE("Existing fence has invalid state");
	mFlinger->mTimeStats->onDestroy(layerID);
	return BAD_VALUE;
	}

	auto incomingStatus = releaseFence->getStatus();
	if (incomingStatus == Fence::Status::Invalid) {
	ALOGE("New fence has invalid state");
	mDrawingState.acquireFence = releaseFence;
	mFlinger->mTimeStats->onDestroy(layerID);
	return BAD_VALUE;
	}

	// If both fences are signaled or both are unsignaled, we need to merge
	// them to get an accurate timestamp.
	if (currentStatus == incomingStatus) {
	char fenceName[32] = {};
	snprintf(fenceName, 32, "%.28s:%d", mName.string(), mFrameNumber);
	sp<Fence> mergedFence =
	Fence::merge(fenceName, mDrawingState.acquireFence, releaseFence);
	if (!mergedFence.get()) {
	ALOGE("failed to merge release fences");
	// synchronization is broken, the best we can do is hope fences
	// signal in order so the new fence will act like a union
	mDrawingState.acquireFence = releaseFence;
	mFlinger->mTimeStats->onDestroy(layerID);
	return BAD_VALUE;
	}
	mDrawingState.acquireFence = mergedFence;
	} else if (incomingStatus == Fence::Status::Unsignaled) {
	// If one fence has signaled and the other hasn't, the unsignaled
	// fence will approximately correspond with the correct timestamp.
	// There's a small race if both fences signal at about the same time
	// and their statuses are retrieved with unfortunate timing. However,
	// by this point, they will have both signaled and only the timestamp
	// will be slightly off; any dependencies after this point will
	// already have been met.
	mDrawingState.acquireFence = releaseFence;
	}
	} else {
	// Bind the new buffer to the GL texture.
	//
	// Older devices require the "implicit" synchronization provided
	// by glEGLImageTargetTexture2DOES, which this method calls. Newer
	// devices will either call this in Layer::onDraw, or (if it's not
	// a GL-composited layer) not at all.
	status_t err = bindTextureImage();
	if (err != NO_ERROR) {
	mFlinger->mTimeStats->onDestroy(layerID);
	return BAD_VALUE;
	}
	}

	// TODO(marissaw): properly support mTimeStats
	mFlinger->mTimeStats->setPostTime(layerID, getFrameNumber(), getName().c_str(), latchTime);
	mFlinger->mTimeStats->setAcquireFence(layerID, getFrameNumber(), getCurrentFenceTime());
	mFlinger->mTimeStats->setLatchTime(layerID, getFrameNumber(), latchTime);

	return NO_ERROR;
	}

	status_t BufferStateLayer::updateActiveBuffer() {
	const State& s(getDrawingState());

	if (s.buffer == nullptr) {
	return BAD_VALUE;
	}

	mActiveBuffer = s.buffer;
	mActiveBufferFence = s.acquireFence;
	getBE().compositionInfo.mBuffer = mActiveBuffer;
	getBE().compositionInfo.mBufferSlot = 0;

	return NO_ERROR;
	}

	bool BufferStateLayer::useCachedBufferForClientComposition() const {
	// TODO: Store a proper staleness bit to support EGLImage caching.
	return false;
	}

	status_t BufferStateLayer::updateFrameNumber(nsecs_t /latchTime/) {
	// TODO(marissaw): support frame history events
	mCurrentFrameNumber = mFrameNumber;
	return NO_ERROR;
	}

	void BufferStateLayer::setHwcLayerBuffer(DisplayId displayId) {
	auto& hwcInfo = getBE().mHwcLayers[displayId];
	auto& hwcLayer = hwcInfo.layer;

	const State& s(getDrawingState());

	// TODO(marissaw): support more than one slot
	uint32_t hwcSlot = 0;

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

	mCurrentStateModified = false;
	mFrameNumber++;
	}

	void BufferStateLayer::onFirstRef() {
	BufferLayer::onFirstRef();

	if (const auto display = mFlinger->getDefaultDisplayDevice()) {
	updateTransformHint(display);
	}
	}

	} // namespace android