services/surfaceflinger/Layer.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
#undef LOG_TAG
#define LOG_TAG "Layer"
#define ATRACE_TAG ATRACE_TAG_GRAPHICS

#include "Layer.h"

#include <android-base/stringprintf.h>
#include <binder/IPCThreadState.h>
#include <compositionengine/Display.h>
#include <compositionengine/Layer.h>
#include <compositionengine/LayerFECompositionState.h>
#include <compositionengine/OutputLayer.h>
#include <compositionengine/impl/OutputLayerCompositionState.h>
#include <cutils/compiler.h>
#include <cutils/native_handle.h>
#include <cutils/properties.h>
#include <gui/BufferItem.h>
#include <gui/LayerDebugInfo.h>
#include <gui/Surface.h>
#include <math.h>
#include <renderengine/RenderEngine.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/types.h>
#include <ui/DebugUtils.h>
#include <ui/GraphicBuffer.h>
#include <ui/PixelFormat.h>
#include <utils/Errors.h>
#include <utils/Log.h>
#include <utils/NativeHandle.h>
#include <utils/StopWatch.h>
#include <utils/Trace.h>

#include <algorithm>
#include <mutex>
#include <sstream>

#include "BufferLayer.h"
#include "ColorLayer.h"
#include "Colorizer.h"
#include "DisplayDevice.h"
#include "DisplayHardware/HWComposer.h"
#include "FrameTracer/FrameTracer.h"
#include "LayerProtoHelper.h"
#include "LayerRejecter.h"
#include "MonitoredProducer.h"
#include "SurfaceFlinger.h"
#include "TimeStats/TimeStats.h"

#define DEBUG_RESIZE 0

namespace android {

using base::StringAppendF;

std::atomic<int32_t> Layer::sSequence{1};

Layer::Layer(const LayerCreationArgs& args)
      : mFlinger(args.flinger),
        mName(args.name),
        mClientRef(args.client),
        mWindowType(args.metadata.getInt32(METADATA_WINDOW_TYPE, 0)) {

    uint32_t layerFlags = 0;
    if (args.flags & ISurfaceComposerClient::eHidden) layerFlags |= layer_state_t::eLayerHidden;
    if (args.flags & ISurfaceComposerClient::eOpaque) layerFlags |= layer_state_t::eLayerOpaque;
    if (args.flags & ISurfaceComposerClient::eSecure) layerFlags |= layer_state_t::eLayerSecure;

    mCurrentState.active_legacy.w = args.w;
    mCurrentState.active_legacy.h = args.h;
    mCurrentState.flags = layerFlags;
    mCurrentState.active_legacy.transform.set(0, 0);
    mCurrentState.crop_legacy.makeInvalid();
    mCurrentState.requestedCrop_legacy = mCurrentState.crop_legacy;
    mCurrentState.z = 0;
    mCurrentState.color.a = 1.0f;
    mCurrentState.layerStack = 0;
    mCurrentState.sequence = 0;
    mCurrentState.requested_legacy = mCurrentState.active_legacy;
    mCurrentState.active.w = UINT32_MAX;
    mCurrentState.active.h = UINT32_MAX;
    mCurrentState.active.transform.set(0, 0);
    mCurrentState.transform = 0;
    mCurrentState.transformToDisplayInverse = false;
    mCurrentState.crop.makeInvalid();
    mCurrentState.acquireFence = new Fence(-1);
    mCurrentState.dataspace = ui::Dataspace::UNKNOWN;
    mCurrentState.hdrMetadata.validTypes = 0;
    mCurrentState.surfaceDamageRegion = Region::INVALID_REGION;
    mCurrentState.cornerRadius = 0.0f;
    mCurrentState.api = -1;
    mCurrentState.hasColorTransform = false;
    mCurrentState.colorSpaceAgnostic = false;
    mCurrentState.metadata = args.metadata;

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

    CompositorTiming compositorTiming;
    args.flinger->getCompositorTiming(&compositorTiming);
    mFrameEventHistory.initializeCompositorTiming(compositorTiming);
    mFrameTracker.setDisplayRefreshPeriod(compositorTiming.interval);

    mCallingPid = args.callingPid;
    mCallingUid = args.callingUid;
    mFlinger->onLayerCreated(this);
}

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

    mFrameTracker.logAndResetStats(mName);
    mFlinger->onLayerDestroyed(this);
}

LayerCreationArgs::LayerCreationArgs(SurfaceFlinger* flinger, const sp<Client>& client,
                                     std::string name, uint32_t w, uint32_t h, uint32_t flags,
                                     LayerMetadata metadata)
      : flinger(flinger),
        client(client),
        name(std::move(name)),
        w(w),
        h(h),
        flags(flags),
        metadata(std::move(metadata)) {
    IPCThreadState* ipc = IPCThreadState::self();
    callingPid = ipc->getCallingPid();
    callingUid = ipc->getCallingUid();
}

// ---------------------------------------------------------------------------
// callbacks
// ---------------------------------------------------------------------------

/*
 * onLayerDisplayed is only meaningful for BufferLayer, but, is called through
 * Layer.  So, the implementation is done in BufferLayer.  When called on a
 * ColorLayer object, it's essentially a NOP.
 */
void Layer::onLayerDisplayed(const sp<Fence>& /*releaseFence*/) {}

void Layer::removeRemoteSyncPoints() {
    for (auto& point : mRemoteSyncPoints) {
        point->setTransactionApplied();
    }
    mRemoteSyncPoints.clear();

    {
        for (State pendingState : mPendingStates) {
            pendingState.barrierLayer_legacy = nullptr;
        }
    }
}

void Layer::removeRelativeZ(const std::vector<Layer*>& layersInTree) {
    if (mCurrentState.zOrderRelativeOf == nullptr) {
        return;
    }

    sp<Layer> strongRelative = mCurrentState.zOrderRelativeOf.promote();
    if (strongRelative == nullptr) {
        setZOrderRelativeOf(nullptr);
        return;
    }

    if (!std::binary_search(layersInTree.begin(), layersInTree.end(), strongRelative.get())) {
        strongRelative->removeZOrderRelative(this);
        mFlinger->setTransactionFlags(eTraversalNeeded);
        setZOrderRelativeOf(nullptr);
    }
}

void Layer::removeFromCurrentState() {
    mRemovedFromCurrentState = true;

    // Since we are no longer reachable from CurrentState SurfaceFlinger
    // will no longer invoke doTransaction for us, and so we will
    // never finish applying transactions. We signal the sync point
    // now so that another layer will not become indefinitely
    // blocked.
    removeRemoteSyncPoints();

    {
    Mutex::Autolock syncLock(mLocalSyncPointMutex);
    for (auto& point : mLocalSyncPoints) {
        point->setFrameAvailable();
    }
    mLocalSyncPoints.clear();
    }

    mFlinger->markLayerPendingRemovalLocked(this);
}

void Layer::onRemovedFromCurrentState() {
    auto layersInTree = getLayersInTree(LayerVector::StateSet::Current);
    std::sort(layersInTree.begin(), layersInTree.end());
    for (const auto& layer : layersInTree) {
        layer->removeFromCurrentState();
        layer->removeRelativeZ(layersInTree);
    }
}

void Layer::addToCurrentState() {
    mRemovedFromCurrentState = false;

    for (const auto& child : mCurrentChildren) {
        child->addToCurrentState();
    }
}

// ---------------------------------------------------------------------------
// set-up
// ---------------------------------------------------------------------------

bool Layer::getPremultipledAlpha() const {
    return mPremultipliedAlpha;
}

sp<IBinder> Layer::getHandle() {
    Mutex::Autolock _l(mLock);
    if (mGetHandleCalled) {
        ALOGE("Get handle called twice" );
        return nullptr;
    }
    mGetHandleCalled = true;
    return new Handle(mFlinger, this);
}

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

static Rect reduce(const Rect& win, const Region& exclude) {
    if (CC_LIKELY(exclude.isEmpty())) {
        return win;
    }
    if (exclude.isRect()) {
        return win.reduce(exclude.getBounds());
    }
    return Region(win).subtract(exclude).getBounds();
}

static FloatRect reduce(const FloatRect& win, const Region& exclude) {
    if (CC_LIKELY(exclude.isEmpty())) {
        return win;
    }
    // Convert through Rect (by rounding) for lack of FloatRegion
    return Region(Rect{win}).subtract(exclude).getBounds().toFloatRect();
}

Rect Layer::getScreenBounds(bool reduceTransparentRegion) const {
    if (!reduceTransparentRegion) {
        return Rect{mScreenBounds};
    }

    FloatRect bounds = getBounds();
    ui::Transform t = getTransform();
    // Transform to screen space.
    bounds = t.transform(bounds);
    return Rect{bounds};
}

FloatRect Layer::getBounds() const {
    const State& s(getDrawingState());
    return getBounds(getActiveTransparentRegion(s));
}

FloatRect Layer::getBounds(const Region& activeTransparentRegion) const {
    // Subtract the transparent region and snap to the bounds.
    return reduce(mBounds, activeTransparentRegion);
}

ui::Transform Layer::getBufferScaleTransform() const {
    // If the layer is not using NATIVE_WINDOW_SCALING_MODE_FREEZE (e.g.
    // it isFixedSize) then there may be additional scaling not accounted
    // for in the layer transform.
    if (!isFixedSize() || getBuffer() == nullptr) {
        return {};
    }

    // If the layer is a buffer state layer, the active width and height
    // could be infinite. In that case, return the effective transform.
    const uint32_t activeWidth = getActiveWidth(getDrawingState());
    const uint32_t activeHeight = getActiveHeight(getDrawingState());
    if (activeWidth >= UINT32_MAX && activeHeight >= UINT32_MAX) {
        return {};
    }

    int bufferWidth = getBuffer()->getWidth();
    int bufferHeight = getBuffer()->getHeight();

    if (getBufferTransform() & NATIVE_WINDOW_TRANSFORM_ROT_90) {
        std::swap(bufferWidth, bufferHeight);
    }

    float sx = activeWidth / static_cast<float>(bufferWidth);
    float sy = activeHeight / static_cast<float>(bufferHeight);

    ui::Transform extraParentScaling;
    extraParentScaling.set(sx, 0, 0, sy);
    return extraParentScaling;
}

ui::Transform Layer::getTransformWithScale(const ui::Transform& bufferScaleTransform) const {
    // We need to mirror this scaling to child surfaces or we will break the contract where WM can
    // treat child surfaces as pixels in the parent surface.
    if (!isFixedSize() || getBuffer() == nullptr) {
        return mEffectiveTransform;
    }
    return mEffectiveTransform * bufferScaleTransform;
}

FloatRect Layer::getBoundsPreScaling(const ui::Transform& bufferScaleTransform) const {
    // We need the pre scaled layer bounds when computing child bounds to make sure the child is
    // cropped to its parent layer after any buffer transform scaling is applied.
    if (!isFixedSize() || getBuffer() == nullptr) {
        return mBounds;
    }
    return bufferScaleTransform.inverse().transform(mBounds);
}

void Layer::computeBounds(FloatRect parentBounds, ui::Transform parentTransform) {
    const State& s(getDrawingState());

    // Calculate effective layer transform
    mEffectiveTransform = parentTransform * getActiveTransform(s);

    // Transform parent bounds to layer space
    parentBounds = getActiveTransform(s).inverse().transform(parentBounds);

    // Calculate source bounds
    mSourceBounds = computeSourceBounds(parentBounds);

    // Calculate bounds by croping diplay frame with layer crop and parent bounds
    FloatRect bounds = mSourceBounds;
    const Rect layerCrop = getCrop(s);
    if (!layerCrop.isEmpty()) {
        bounds = mSourceBounds.intersect(layerCrop.toFloatRect());
    }
    bounds = bounds.intersect(parentBounds);

    mBounds = bounds;
    mScreenBounds = mEffectiveTransform.transform(mBounds);

    // Add any buffer scaling to the layer's children.
    ui::Transform bufferScaleTransform = getBufferScaleTransform();
    for (const sp<Layer>& child : mDrawingChildren) {
        child->computeBounds(getBoundsPreScaling(bufferScaleTransform),
                             getTransformWithScale(bufferScaleTransform));
    }
}

Rect Layer::getCroppedBufferSize(const State& s) const {
    Rect size = getBufferSize(s);
    Rect crop = getCrop(s);
    if (!crop.isEmpty() && size.isValid()) {
        size.intersect(crop, &size);
    } else if (!crop.isEmpty()) {
        size = crop;
    }
    return size;
}

void Layer::setupRoundedCornersCropCoordinates(Rect win,
                                               const FloatRect& roundedCornersCrop) const {
    // Translate win by the rounded corners rect coordinates, to have all values in
    // layer coordinate space.
    win.left -= roundedCornersCrop.left;
    win.right -= roundedCornersCrop.left;
    win.top -= roundedCornersCrop.top;
    win.bottom -= roundedCornersCrop.top;
}

void Layer::latchBasicGeometry(compositionengine::LayerFECompositionState& compositionState) const {
    const auto& drawingState{getDrawingState()};
    const uint32_t layerStack = getLayerStack();
    const auto alpha = static_cast<float>(getAlpha());
    const bool opaque = isOpaque(drawingState);
    const bool usesRoundedCorners = getRoundedCornerState().radius != 0.f;

    auto blendMode = Hwc2::IComposerClient::BlendMode::NONE;
    if (!opaque || alpha != 1.0f) {
        blendMode = mPremultipliedAlpha ? Hwc2::IComposerClient::BlendMode::PREMULTIPLIED
                                        : Hwc2::IComposerClient::BlendMode::COVERAGE;
    }

    // TODO(b/121291683): Instead of filling in a passed-in compositionState
    // structure, switch to Layer owning the structure and have
    // CompositionEngine be able to get a reference to it.

    compositionState.layerStackId =
            (layerStack != ~0u) ? std::make_optional(layerStack) : std::nullopt;
    compositionState.internalOnly = getPrimaryDisplayOnly();
    compositionState.isVisible = isVisible();
    compositionState.isOpaque = opaque && !usesRoundedCorners && alpha == 1.f;

    compositionState.contentDirty = contentDirty;
    contentDirty = false;

    compositionState.geomLayerBounds = mBounds;
    compositionState.geomLayerTransform = getTransform();
    compositionState.geomInverseLayerTransform = compositionState.geomLayerTransform.inverse();
    compositionState.transparentRegionHint = getActiveTransparentRegion(drawingState);

    compositionState.blendMode = static_cast<Hwc2::IComposerClient::BlendMode>(blendMode);
    compositionState.alpha = alpha;
}

void Layer::latchGeometry(compositionengine::LayerFECompositionState& compositionState) const {
    const auto& drawingState{getDrawingState()};

    int type = drawingState.metadata.getInt32(METADATA_WINDOW_TYPE, 0);
    int appId = drawingState.metadata.getInt32(METADATA_OWNER_UID, 0);
    sp<Layer> parent = mDrawingParent.promote();
    if (parent.get()) {
        auto& parentState = parent->getDrawingState();
        const int parentType = parentState.metadata.getInt32(METADATA_WINDOW_TYPE, 0);
        const int parentAppId = parentState.metadata.getInt32(METADATA_OWNER_UID, 0);
        if (parentType > 0 && parentAppId > 0) {
            type = parentType;
            appId = parentAppId;
        }
    }

    compositionState.geomBufferSize = getBufferSize(drawingState);
    compositionState.geomContentCrop = getBufferCrop();
    compositionState.geomCrop = getCrop(drawingState);
    compositionState.geomBufferTransform = getBufferTransform();
    compositionState.geomBufferUsesDisplayInverseTransform = getTransformToDisplayInverse();
    compositionState.geomUsesSourceCrop = usesSourceCrop();
    compositionState.isSecure = isSecure();

    compositionState.type = type;
    compositionState.appId = appId;
}

void Layer::latchPerFrameState(compositionengine::LayerFECompositionState& compositionState) const {
    const auto& drawingState{getDrawingState()};
    compositionState.forceClientComposition = false;

    compositionState.isColorspaceAgnostic = isColorSpaceAgnostic();
    compositionState.dataspace = getDataSpace();
    compositionState.colorTransform = getColorTransform();
    compositionState.colorTransformIsIdentity = !hasColorTransform();
    compositionState.surfaceDamage = surfaceDamageRegion;
    compositionState.hasProtectedContent = isProtected();

    const bool usesRoundedCorners = getRoundedCornerState().radius != 0.f;
    compositionState.isOpaque =
            isOpaque(drawingState) && !usesRoundedCorners && getAlpha() == 1.0_hf;

    // Force client composition for special cases known only to the front-end.
    if (isHdrY410() || usesRoundedCorners) {
        compositionState.forceClientComposition = true;
    }
}

void Layer::latchCursorCompositionState(
        compositionengine::LayerFECompositionState& compositionState) const {
    // This gives us only the "orientation" component of the transform
    const State& drawingState{getDrawingState()};

    // Apply the layer's transform, followed by the display's global transform
    // Here we're guaranteed that the layer's transform preserves rects
    Rect win = getCroppedBufferSize(drawingState);
    // Subtract the transparent region and snap to the bounds
    Rect bounds = reduce(win, getActiveTransparentRegion(drawingState));
    Rect frame(getTransform().transform(bounds));

    compositionState.cursorFrame = frame;
}

bool Layer::onPreComposition(nsecs_t) {
    return false;
}

void Layer::latchCompositionState(compositionengine::LayerFECompositionState& compositionState,
                                  compositionengine::LayerFE::StateSubset subset) const {
    using StateSubset = compositionengine::LayerFE::StateSubset;

    switch (subset) {
        case StateSubset::BasicGeometry:
            latchBasicGeometry(compositionState);
            break;

        case StateSubset::GeometryAndContent:
            latchBasicGeometry(compositionState);
            latchGeometry(compositionState);
            latchPerFrameState(compositionState);
            break;

        case StateSubset::Content:
            latchPerFrameState(compositionState);
            break;
    }
}

const char* Layer::getDebugName() const {
    return mName.c_str();
}

// ---------------------------------------------------------------------------
// drawing...
// ---------------------------------------------------------------------------

std::optional<renderengine::LayerSettings> Layer::prepareClientComposition(
        compositionengine::LayerFE::ClientCompositionTargetSettings& targetSettings) {
    if (!getCompositionLayer()) {
        return {};
    }

    FloatRect bounds = getBounds();
    half alpha = getAlpha();
    renderengine::LayerSettings layerSettings;
    layerSettings.geometry.boundaries = bounds;
    if (targetSettings.useIdentityTransform) {
        layerSettings.geometry.positionTransform = mat4();
    } else {
        layerSettings.geometry.positionTransform = getTransform().asMatrix4();
    }

    if (hasColorTransform()) {
        layerSettings.colorTransform = getColorTransform();
    }

    const auto roundedCornerState = getRoundedCornerState();
    layerSettings.geometry.roundedCornersRadius = roundedCornerState.radius;
    layerSettings.geometry.roundedCornersCrop = roundedCornerState.cropRect;

    layerSettings.alpha = alpha;
    layerSettings.sourceDataspace = getDataSpace();
    return layerSettings;
}

Hwc2::IComposerClient::Composition Layer::getCompositionType(
        const sp<const DisplayDevice>& display) const {
    const auto outputLayer = findOutputLayerForDisplay(display);
    LOG_FATAL_IF(!outputLayer);
    return outputLayer->getState().hwc ? (*outputLayer->getState().hwc).hwcCompositionType
                                       : Hwc2::IComposerClient::Composition::CLIENT;
}

bool Layer::getClearClientTarget(const sp<const DisplayDevice>& display) const {
    const auto outputLayer = findOutputLayerForDisplay(display);
    LOG_FATAL_IF(!outputLayer);
    return outputLayer->getState().clearClientTarget;
}

bool Layer::addSyncPoint(const std::shared_ptr<SyncPoint>& point) {
    if (point->getFrameNumber() <= mCurrentFrameNumber) {
        // Don't bother with a SyncPoint, since we've already latched the
        // relevant frame
        return false;
    }
    if (isRemovedFromCurrentState()) {
        return false;
    }

    Mutex::Autolock lock(mLocalSyncPointMutex);
    mLocalSyncPoints.push_back(point);
    return true;
}

// ----------------------------------------------------------------------------
// local state
// ----------------------------------------------------------------------------

bool Layer::isSecure() const {
    const State& s(mDrawingState);
    return (s.flags & layer_state_t::eLayerSecure);
}

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

void Layer::pushPendingState() {
    if (!mCurrentState.modified) {
        return;
    }
    ATRACE_CALL();

    // If this transaction is waiting on the receipt of a frame, generate a sync
    // point and send it to the remote layer.
    // We don't allow installing sync points after we are removed from the current state
    // as we won't be able to signal our end.
    if (mCurrentState.barrierLayer_legacy != nullptr && !isRemovedFromCurrentState()) {
        sp<Layer> barrierLayer = mCurrentState.barrierLayer_legacy.promote();
        if (barrierLayer == nullptr) {
            ALOGE("[%s] Unable to promote barrier Layer.", getDebugName());
            // If we can't promote the layer we are intended to wait on,
            // then it is expired or otherwise invalid. Allow this transaction
            // to be applied as per normal (no synchronization).
            mCurrentState.barrierLayer_legacy = nullptr;
        } else {
            auto syncPoint = std::make_shared<SyncPoint>(mCurrentState.frameNumber_legacy, this);
            if (barrierLayer->addSyncPoint(syncPoint)) {
                std::stringstream ss;
                ss << "Adding sync point " << mCurrentState.frameNumber_legacy;
                ATRACE_NAME(ss.str().c_str());
                mRemoteSyncPoints.push_back(std::move(syncPoint));
            } else {
                // We already missed the frame we're supposed to synchronize
                // on, so go ahead and apply the state update
                mCurrentState.barrierLayer_legacy = nullptr;
            }
        }

        // Wake us up to check if the frame has been received
        setTransactionFlags(eTransactionNeeded);
        mFlinger->setTransactionFlags(eTraversalNeeded);
    }
    mPendingStates.push_back(mCurrentState);
    ATRACE_INT(mTransactionName.c_str(), mPendingStates.size());
}

void Layer::popPendingState(State* stateToCommit) {
    ATRACE_CALL();
    *stateToCommit = mPendingStates[0];

    mPendingStates.removeAt(0);
    ATRACE_INT(mTransactionName.c_str(), mPendingStates.size());
}

bool Layer::applyPendingStates(State* stateToCommit) {
    bool stateUpdateAvailable = false;
    while (!mPendingStates.empty()) {
        if (mPendingStates[0].barrierLayer_legacy != nullptr) {
            if (mRemoteSyncPoints.empty()) {
                // If we don't have a sync point for this, apply it anyway. It
                // will be visually wrong, but it should keep us from getting
                // into too much trouble.
                ALOGE("[%s] No local sync point found", getDebugName());
                popPendingState(stateToCommit);
                stateUpdateAvailable = true;
                continue;
            }

            if (mRemoteSyncPoints.front()->getFrameNumber() !=
                mPendingStates[0].frameNumber_legacy) {
                ALOGE("[%s] Unexpected sync point frame number found", getDebugName());

                // Signal our end of the sync point and then dispose of it
                mRemoteSyncPoints.front()->setTransactionApplied();
                mRemoteSyncPoints.pop_front();
                continue;
            }

            if (mRemoteSyncPoints.front()->frameIsAvailable()) {
                ATRACE_NAME("frameIsAvailable");
                // Apply the state update
                popPendingState(stateToCommit);
                stateUpdateAvailable = true;

                // Signal our end of the sync point and then dispose of it
                mRemoteSyncPoints.front()->setTransactionApplied();
                mRemoteSyncPoints.pop_front();
            } else {
                ATRACE_NAME("!frameIsAvailable");
                break;
            }
        } else {
            popPendingState(stateToCommit);
            stateUpdateAvailable = true;
        }
    }

    // If we still have pending updates, wake SurfaceFlinger back up and point
    // it at this layer so we can process them
    if (!mPendingStates.empty()) {
        setTransactionFlags(eTransactionNeeded);
        mFlinger->setTransactionFlags(eTraversalNeeded);
    }

    mCurrentState.modified = false;
    return stateUpdateAvailable;
}

uint32_t Layer::doTransactionResize(uint32_t flags, State* stateToCommit) {
    const State& s(getDrawingState());

    const bool sizeChanged = (stateToCommit->requested_legacy.w != s.requested_legacy.w) ||
            (stateToCommit->requested_legacy.h != s.requested_legacy.h);

    if (sizeChanged) {
        // the size changed, we need to ask our client to request a new buffer
        ALOGD_IF(DEBUG_RESIZE,
                 "doTransaction: geometry (layer=%p '%s'), tr=%02x, scalingMode=%d\n"
                 "  current={ active   ={ wh={%4u,%4u} crop={%4d,%4d,%4d,%4d} (%4d,%4d) }\n"
                 "            requested={ wh={%4u,%4u} }}\n"
                 "  drawing={ active   ={ wh={%4u,%4u} crop={%4d,%4d,%4d,%4d} (%4d,%4d) }\n"
                 "            requested={ wh={%4u,%4u} }}\n",
                 this, getName().c_str(), getBufferTransform(), getEffectiveScalingMode(),
                 stateToCommit->active_legacy.w, stateToCommit->active_legacy.h,
                 stateToCommit->crop_legacy.left, stateToCommit->crop_legacy.top,
                 stateToCommit->crop_legacy.right, stateToCommit->crop_legacy.bottom,
                 stateToCommit->crop_legacy.getWidth(), stateToCommit->crop_legacy.getHeight(),
                 stateToCommit->requested_legacy.w, stateToCommit->requested_legacy.h,
                 s.active_legacy.w, s.active_legacy.h, s.crop_legacy.left, s.crop_legacy.top,
                 s.crop_legacy.right, s.crop_legacy.bottom, s.crop_legacy.getWidth(),
                 s.crop_legacy.getHeight(), s.requested_legacy.w, s.requested_legacy.h);
    }

    // Don't let Layer::doTransaction update the drawing state
    // if we have a pending resize, unless we are in fixed-size mode.
    // the drawing state will be updated only once we receive a buffer
    // with the correct size.
    //
    // In particular, we want to make sure the clip (which is part
    // of the geometry state) is latched together with the size but is
    // latched immediately when no resizing is involved.
    //
    // If a sideband stream is attached, however, we want to skip this
    // optimization so that transactions aren't missed when a buffer
    // never arrives
    //
    // In the case that we don't have a buffer we ignore other factors
    // and avoid entering the resizePending state. At a high level the
    // resizePending state is to avoid applying the state of the new buffer
    // to the old buffer. However in the state where we don't have an old buffer
    // there is no such concern but we may still be being used as a parent layer.
    const bool resizePending =
            ((stateToCommit->requested_legacy.w != stateToCommit->active_legacy.w) ||
             (stateToCommit->requested_legacy.h != stateToCommit->active_legacy.h)) &&
            (getBuffer() != nullptr);
    if (!isFixedSize()) {
        if (resizePending && mSidebandStream == nullptr) {
            flags |= eDontUpdateGeometryState;
        }
    }

    // Here we apply various requested geometry states, depending on our
    // latching configuration. See Layer.h for a detailed discussion of
    // how geometry latching is controlled.
    if (!(flags & eDontUpdateGeometryState)) {
        State& editCurrentState(getCurrentState());

        // There is an awkward asymmetry in the handling of the crop states in the position
        // states, as can be seen below. Largely this arises from position and transform
        // being stored in the same data structure while having different latching rules.
        // b/38182305
        //
        // Careful that "stateToCommit" and editCurrentState may not begin as equivalent due to
        // applyPendingStates in the presence of deferred transactions.
        editCurrentState.active_legacy = editCurrentState.requested_legacy;
        stateToCommit->active_legacy = stateToCommit->requested_legacy;
    }

    return flags;
}

uint32_t Layer::doTransaction(uint32_t flags) {
    ATRACE_CALL();

    if (mLayerDetached) {
        // Ensure BLAST buffer callbacks are processed.
        // detachChildren and mLayerDetached were implemented to avoid geometry updates
        // to layers in the cases of animation. For BufferQueue layers buffers are still
        // consumed as normal. This is useful as otherwise the client could get hung
        // inevitably waiting on a buffer to return. We recreate this semantic for BufferQueue
        // even though it is a little consistent. detachChildren is shortly slated for removal
        // by the hierarchy mirroring work so we don't need to worry about it too much.
        mDrawingState.callbackHandles = mCurrentState.callbackHandles;
        mCurrentState.callbackHandles = {};
        return flags;
    }

    if (mChildrenChanged) {
        flags |= eVisibleRegion;
        mChildrenChanged = false;
    }

    pushPendingState();
    State c = getCurrentState();
    if (!applyPendingStates(&c)) {
        return flags;
    }

    flags = doTransactionResize(flags, &c);

    const State& s(getDrawingState());

    if (getActiveGeometry(c) != getActiveGeometry(s)) {
        // invalidate and recompute the visible regions if needed
        flags |= Layer::eVisibleRegion;
    }

    if (c.sequence != s.sequence) {
        // invalidate and recompute the visible regions if needed
        flags |= eVisibleRegion;
        this->contentDirty = true;

        // we may use linear filtering, if the matrix scales us
        const uint8_t type = getActiveTransform(c).getType();
        mNeedsFiltering = (!getActiveTransform(c).preserveRects() || type >= ui::Transform::SCALE);
    }

    if (mCurrentState.inputInfoChanged) {
        flags |= eInputInfoChanged;
        mCurrentState.inputInfoChanged = false;
    }

    // Commit the transaction
    commitTransaction(c);
    mPendingStatesSnapshot = mPendingStates;
    mCurrentState.callbackHandles = {};
    return flags;
}

void Layer::commitTransaction(const State& stateToCommit) {
    mDrawingState = stateToCommit;
}

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

uint32_t Layer::setTransactionFlags(uint32_t flags) {
    return mTransactionFlags.fetch_or(flags);
}

bool Layer::setPosition(float x, float y) {
    if (mCurrentState.requested_legacy.transform.tx() == x &&
        mCurrentState.requested_legacy.transform.ty() == y)
        return false;
    mCurrentState.sequence++;

    // We update the requested and active position simultaneously because
    // we want to apply the position portion of the transform matrix immediately,
    // but still delay scaling when resizing a SCALING_MODE_FREEZE layer.
    mCurrentState.requested_legacy.transform.set(x, y);
    // Here we directly update the active state
    // unlike other setters, because we store it within
    // the transform, but use different latching rules.
    // b/38182305
    mCurrentState.active_legacy.transform.set(x, y);

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

bool Layer::setChildLayer(const sp<Layer>& childLayer, int32_t z) {
    ssize_t idx = mCurrentChildren.indexOf(childLayer);
    if (idx < 0) {
        return false;
    }
    if (childLayer->setLayer(z)) {
        mCurrentChildren.removeAt(idx);
        mCurrentChildren.add(childLayer);
        return true;
    }
    return false;
}

bool Layer::setChildRelativeLayer(const sp<Layer>& childLayer,
        const sp<IBinder>& relativeToHandle, int32_t relativeZ) {
    ssize_t idx = mCurrentChildren.indexOf(childLayer);
    if (idx < 0) {
        return false;
    }
    if (childLayer->setRelativeLayer(relativeToHandle, relativeZ)) {
        mCurrentChildren.removeAt(idx);
        mCurrentChildren.add(childLayer);
        return true;
    }
    return false;
}

bool Layer::setLayer(int32_t z) {
    if (mCurrentState.z == z && !usingRelativeZ(LayerVector::StateSet::Current)) return false;
    mCurrentState.sequence++;
    mCurrentState.z = z;
    mCurrentState.modified = true;

    // Discard all relative layering.
    if (mCurrentState.zOrderRelativeOf != nullptr) {
        sp<Layer> strongRelative = mCurrentState.zOrderRelativeOf.promote();
        if (strongRelative != nullptr) {
            strongRelative->removeZOrderRelative(this);
        }
        setZOrderRelativeOf(nullptr);
    }
    setTransactionFlags(eTransactionNeeded);
    return true;
}

void Layer::removeZOrderRelative(const wp<Layer>& relative) {
    mCurrentState.zOrderRelatives.remove(relative);
    mCurrentState.sequence++;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
}

void Layer::addZOrderRelative(const wp<Layer>& relative) {
    mCurrentState.zOrderRelatives.add(relative);
    mCurrentState.modified = true;
    mCurrentState.sequence++;
    setTransactionFlags(eTransactionNeeded);
}

void Layer::setZOrderRelativeOf(const wp<Layer>& relativeOf) {
    mCurrentState.zOrderRelativeOf = relativeOf;
    mCurrentState.sequence++;
    mCurrentState.modified = true;
    mCurrentState.isRelativeOf = relativeOf != nullptr;

    setTransactionFlags(eTransactionNeeded);
}

bool Layer::setRelativeLayer(const sp<IBinder>& relativeToHandle, int32_t relativeZ) {
    sp<Handle> handle = static_cast<Handle*>(relativeToHandle.get());
    if (handle == nullptr) {
        return false;
    }
    sp<Layer> relative = handle->owner.promote();
    if (relative == nullptr) {
        return false;
    }

    if (mCurrentState.z == relativeZ && usingRelativeZ(LayerVector::StateSet::Current) &&
        mCurrentState.zOrderRelativeOf == relative) {
        return false;
    }

    mCurrentState.sequence++;
    mCurrentState.modified = true;
    mCurrentState.z = relativeZ;

    auto oldZOrderRelativeOf = mCurrentState.zOrderRelativeOf.promote();
    if (oldZOrderRelativeOf != nullptr) {
        oldZOrderRelativeOf->removeZOrderRelative(this);
    }
    setZOrderRelativeOf(relative);
    relative->addZOrderRelative(this);

    setTransactionFlags(eTransactionNeeded);

    return true;
}

bool Layer::setSize(uint32_t w, uint32_t h) {
    if (mCurrentState.requested_legacy.w == w && mCurrentState.requested_legacy.h == h)
        return false;
    mCurrentState.requested_legacy.w = w;
    mCurrentState.requested_legacy.h = h;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);

    // record the new size, from this point on, when the client request
    // a buffer, it'll get the new size.
    setDefaultBufferSize(mCurrentState.requested_legacy.w, mCurrentState.requested_legacy.h);
    return true;
}
bool Layer::setAlpha(float alpha) {
    if (mCurrentState.color.a == alpha) return false;
    mCurrentState.sequence++;
    mCurrentState.color.a = alpha;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setBackgroundColor(const half3& color, float alpha, ui::Dataspace dataspace) {
    if (!mCurrentState.bgColorLayer && alpha == 0) {
        return false;
    }
    mCurrentState.sequence++;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);

    if (!mCurrentState.bgColorLayer && alpha != 0) {
        // create background color layer if one does not yet exist
        uint32_t flags = ISurfaceComposerClient::eFXSurfaceColor;
        std::string name = mName + "BackgroundColorLayer";
        mCurrentState.bgColorLayer = mFlinger->getFactory().createColorLayer(
                LayerCreationArgs(mFlinger.get(), nullptr, std::move(name), 0, 0, flags,
                                  LayerMetadata()));

        // add to child list
        addChild(mCurrentState.bgColorLayer);
        mFlinger->mLayersAdded = true;
        // set up SF to handle added color layer
        if (isRemovedFromCurrentState()) {
            mCurrentState.bgColorLayer->onRemovedFromCurrentState();
        }
        mFlinger->setTransactionFlags(eTransactionNeeded);
    } else if (mCurrentState.bgColorLayer && alpha == 0) {
        mCurrentState.bgColorLayer->reparent(nullptr);
        mCurrentState.bgColorLayer = nullptr;
        return true;
    }

    mCurrentState.bgColorLayer->setColor(color);
    mCurrentState.bgColorLayer->setLayer(std::numeric_limits<int32_t>::min());
    mCurrentState.bgColorLayer->setAlpha(alpha);
    mCurrentState.bgColorLayer->setDataspace(dataspace);

    return true;
}

bool Layer::setCornerRadius(float cornerRadius) {
    if (mCurrentState.cornerRadius == cornerRadius) return false;

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

bool Layer::setMatrix(const layer_state_t::matrix22_t& matrix,
        bool allowNonRectPreservingTransforms) {
    ui::Transform t;
    t.set(matrix.dsdx, matrix.dtdy, matrix.dtdx, matrix.dsdy);

    if (!allowNonRectPreservingTransforms && !t.preserveRects()) {
        ALOGW("Attempt to set rotation matrix without permission ACCESS_SURFACE_FLINGER ignored");
        return false;
    }
    mCurrentState.sequence++;
    mCurrentState.requested_legacy.transform.set(matrix.dsdx, matrix.dtdy, matrix.dtdx,
                                                 matrix.dsdy);
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setTransparentRegionHint(const Region& transparent) {
    mCurrentState.requestedTransparentRegion_legacy = transparent;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}
bool Layer::setFlags(uint8_t flags, uint8_t mask) {
    const uint32_t newFlags = (mCurrentState.flags & ~mask) | (flags & mask);
    if (mCurrentState.flags == newFlags) return false;
    mCurrentState.sequence++;
    mCurrentState.flags = newFlags;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setCrop_legacy(const Rect& crop) {
    if (mCurrentState.requestedCrop_legacy == crop) return false;
    mCurrentState.sequence++;
    mCurrentState.requestedCrop_legacy = crop;
    mCurrentState.crop_legacy = crop;

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

bool Layer::setOverrideScalingMode(int32_t scalingMode) {
    if (scalingMode == mOverrideScalingMode) return false;
    mOverrideScalingMode = scalingMode;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setMetadata(const LayerMetadata& data) {
    if (!mCurrentState.metadata.merge(data, true /* eraseEmpty */)) return false;
    mCurrentState.sequence++;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setLayerStack(uint32_t layerStack) {
    if (mCurrentState.layerStack == layerStack) return false;
    mCurrentState.sequence++;
    mCurrentState.layerStack = layerStack;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

bool Layer::setColorSpaceAgnostic(const bool agnostic) {
    if (mCurrentState.colorSpaceAgnostic == agnostic) {
        return false;
    }
    mCurrentState.sequence++;
    mCurrentState.colorSpaceAgnostic = agnostic;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

uint32_t Layer::getLayerStack() const {
    auto p = mDrawingParent.promote();
    if (p == nullptr) {
        return getDrawingState().layerStack;
    }
    return p->getLayerStack();
}

void Layer::deferTransactionUntil_legacy(const sp<Layer>& barrierLayer, uint64_t frameNumber) {
    ATRACE_CALL();
    mCurrentState.barrierLayer_legacy = barrierLayer;
    mCurrentState.frameNumber_legacy = frameNumber;
    // We don't set eTransactionNeeded, because just receiving a deferral
    // request without any other state updates shouldn't actually induce a delay
    mCurrentState.modified = true;
    pushPendingState();
    mCurrentState.barrierLayer_legacy = nullptr;
    mCurrentState.frameNumber_legacy = 0;
    mCurrentState.modified = false;
}

void Layer::deferTransactionUntil_legacy(const sp<IBinder>& barrierHandle, uint64_t frameNumber) {
    sp<Handle> handle = static_cast<Handle*>(barrierHandle.get());
    deferTransactionUntil_legacy(handle->owner.promote(), frameNumber);
}

// ----------------------------------------------------------------------------
// pageflip handling...
// ----------------------------------------------------------------------------

bool Layer::isHiddenByPolicy() const {
    const State& s(mDrawingState);
    const auto& parent = mDrawingParent.promote();
    if (parent != nullptr && parent->isHiddenByPolicy()) {
        return true;
    }
    if (usingRelativeZ(LayerVector::StateSet::Drawing)) {
        auto zOrderRelativeOf = mDrawingState.zOrderRelativeOf.promote();
        if (zOrderRelativeOf != nullptr) {
            if (zOrderRelativeOf->isHiddenByPolicy()) {
                return true;
            }
        }
    }
    return s.flags & layer_state_t::eLayerHidden;
}

uint32_t Layer::getEffectiveUsage(uint32_t usage) const {
    // TODO: should we do something special if mSecure is set?
    if (mProtectedByApp) {
        // need a hardware-protected path to external video sink
        usage |= GraphicBuffer::USAGE_PROTECTED;
    }
    if (mPotentialCursor) {
        usage |= GraphicBuffer::USAGE_CURSOR;
    }
    usage |= GraphicBuffer::USAGE_HW_COMPOSER;
    return usage;
}

void Layer::updateTransformHint(const sp<const DisplayDevice>& display) const {
    uint32_t orientation = 0;
    // Disable setting transform hint if the debug flag is set.
    if (!mFlinger->mDebugDisableTransformHint) {
        // The transform hint is used to improve performance, but we can
        // only have a single transform hint, it cannot
        // apply to all displays.
        const ui::Transform& planeTransform = display->getTransform();
        orientation = planeTransform.getOrientation();
        if (orientation & ui::Transform::ROT_INVALID) {
            orientation = 0;
        }
    }
    setTransformHint(orientation);
}

// ----------------------------------------------------------------------------
// debugging
// ----------------------------------------------------------------------------

// TODO(marissaw): add new layer state info to layer debugging
LayerDebugInfo Layer::getLayerDebugInfo() const {
    using namespace std::string_literals;

    LayerDebugInfo info;
    const State& ds = getDrawingState();
    info.mName = getName();
    sp<Layer> parent = getParent();
    info.mParentName = parent ? parent->getName() : "none"s;
    info.mType = getType();
    info.mTransparentRegion = ds.activeTransparentRegion_legacy;

    info.mVisibleRegion = debugGetVisibleRegionOnDefaultDisplay();
    info.mSurfaceDamageRegion = surfaceDamageRegion;
    info.mLayerStack = getLayerStack();
    info.mX = ds.active_legacy.transform.tx();
    info.mY = ds.active_legacy.transform.ty();
    info.mZ = ds.z;
    info.mWidth = ds.active_legacy.w;
    info.mHeight = ds.active_legacy.h;
    info.mCrop = ds.crop_legacy;
    info.mColor = ds.color;
    info.mFlags = ds.flags;
    info.mPixelFormat = getPixelFormat();
    info.mDataSpace = static_cast<android_dataspace>(getDataSpace());
    info.mMatrix[0][0] = ds.active_legacy.transform[0][0];
    info.mMatrix[0][1] = ds.active_legacy.transform[0][1];
    info.mMatrix[1][0] = ds.active_legacy.transform[1][0];
    info.mMatrix[1][1] = ds.active_legacy.transform[1][1];
    {
        sp<const GraphicBuffer> buffer = getBuffer();
        if (buffer != 0) {
            info.mActiveBufferWidth = buffer->getWidth();
            info.mActiveBufferHeight = buffer->getHeight();
            info.mActiveBufferStride = buffer->getStride();
            info.mActiveBufferFormat = buffer->format;
        } else {
            info.mActiveBufferWidth = 0;
            info.mActiveBufferHeight = 0;
            info.mActiveBufferStride = 0;
            info.mActiveBufferFormat = 0;
        }
    }
    info.mNumQueuedFrames = getQueuedFrameCount();
    info.mRefreshPending = isBufferLatched();
    info.mIsOpaque = isOpaque(ds);
    info.mContentDirty = contentDirty;
    return info;
}

void Layer::miniDumpHeader(std::string& result) {
    result.append("-------------------------------");
    result.append("-------------------------------");
    result.append("-----------------------------\n");
    result.append(" Layer name\n");
    result.append("           Z | ");
    result.append(" Window Type | ");
    result.append(" Comp Type | ");
    result.append(" Transform | ");
    result.append("  Disp Frame (LTRB) | ");
    result.append("         Source Crop (LTRB)\n");
    result.append("-------------------------------");
    result.append("-------------------------------");
    result.append("-----------------------------\n");
}

void Layer::miniDump(std::string& result, const sp<DisplayDevice>& displayDevice) const {
    auto outputLayer = findOutputLayerForDisplay(displayDevice);
    if (!outputLayer) {
        return;
    }

    std::string name;
    if (mName.length() > 77) {
        std::string shortened;
        shortened.append(mName, 0, 36);
        shortened.append("[...]");
        shortened.append(mName, mName.length() - 36);
        name = std::move(shortened);
    } else {
        name = mName;
    }

    StringAppendF(&result, " %s\n", name.c_str());

    const State& layerState(getDrawingState());
    const auto& compositionState = outputLayer->getState();

    if (layerState.zOrderRelativeOf != nullptr || mDrawingParent != nullptr) {
        StringAppendF(&result, "  rel %6d | ", layerState.z);
    } else {
        StringAppendF(&result, "  %10d | ", layerState.z);
    }
    StringAppendF(&result, "  %10d | ", mWindowType);
    StringAppendF(&result, "%10s | ", toString(getCompositionType(displayDevice)).c_str());
    StringAppendF(&result, "%10s | ",
                  toString(getCompositionLayer() ? compositionState.bufferTransform
                                                 : static_cast<Hwc2::Transform>(0))
                          .c_str());
    const Rect& frame = compositionState.displayFrame;
    StringAppendF(&result, "%4d %4d %4d %4d | ", frame.left, frame.top, frame.right, frame.bottom);
    const FloatRect& crop = compositionState.sourceCrop;
    StringAppendF(&result, "%6.1f %6.1f %6.1f %6.1f\n", crop.left, crop.top, crop.right,
                  crop.bottom);

    result.append("- - - - - - - - - - - - - - - -");
    result.append("- - - - - - - - - - - - - - - -");
    result.append("- - - - - - - - - - - - - - -\n");
}

void Layer::dumpFrameStats(std::string& result) const {
    mFrameTracker.dumpStats(result);
}

void Layer::clearFrameStats() {
    mFrameTracker.clearStats();
}

void Layer::logFrameStats() {
    mFrameTracker.logAndResetStats(mName);
}

void Layer::getFrameStats(FrameStats* outStats) const {
    mFrameTracker.getStats(outStats);
}

void Layer::dumpFrameEvents(std::string& result) {
    StringAppendF(&result, "- Layer %s (%s, %p)\n", getName().c_str(), getType(), this);
    Mutex::Autolock lock(mFrameEventHistoryMutex);
    mFrameEventHistory.checkFencesForCompletion();
    mFrameEventHistory.dump(result);
}

void Layer::dumpCallingUidPid(std::string& result) const {
    StringAppendF(&result, "Layer %s (%s) pid:%d uid:%d\n", getName().c_str(), getType(),
                  mCallingPid, mCallingUid);
}

void Layer::onDisconnect() {
    Mutex::Autolock lock(mFrameEventHistoryMutex);
    mFrameEventHistory.onDisconnect();
    const int32_t layerID = getSequence();
    mFlinger->mTimeStats->onDestroy(layerID);
    mFlinger->mFrameTracer->onDestroy(layerID);
}

void Layer::addAndGetFrameTimestamps(const NewFrameEventsEntry* newTimestamps,
                                     FrameEventHistoryDelta* outDelta) {
    if (newTimestamps) {
        mFlinger->mTimeStats->setPostTime(getSequence(), newTimestamps->frameNumber,
                                          getName().c_str(), newTimestamps->postedTime);
    }

    Mutex::Autolock lock(mFrameEventHistoryMutex);
    if (newTimestamps) {
        // If there are any unsignaled fences in the aquire timeline at this
        // point, the previously queued frame hasn't been latched yet. Go ahead
        // and try to get the signal time here so the syscall is taken out of
        // the main thread's critical path.
        mAcquireTimeline.updateSignalTimes();
        // Push the new fence after updating since it's likely still pending.
        mAcquireTimeline.push(newTimestamps->acquireFence);
        mFrameEventHistory.addQueue(*newTimestamps);
    }

    if (outDelta) {
        mFrameEventHistory.getAndResetDelta(outDelta);
    }
}

size_t Layer::getChildrenCount() const {
    size_t count = 0;
    for (const sp<Layer>& child : mCurrentChildren) {
        count += 1 + child->getChildrenCount();
    }
    return count;
}

void Layer::addChild(const sp<Layer>& layer) {
    mChildrenChanged = true;
    setTransactionFlags(eTransactionNeeded);

    mCurrentChildren.add(layer);
    layer->setParent(this);
}

ssize_t Layer::removeChild(const sp<Layer>& layer) {
    mChildrenChanged = true;
    setTransactionFlags(eTransactionNeeded);

    layer->setParent(nullptr);
    return mCurrentChildren.remove(layer);
}

bool Layer::reparentChildren(const sp<IBinder>& newParentHandle) {
    sp<Handle> handle = nullptr;
    sp<Layer> newParent = nullptr;
    if (newParentHandle == nullptr) {
        return false;
    }
    handle = static_cast<Handle*>(newParentHandle.get());
    newParent = handle->owner.promote();
    if (newParent == nullptr) {
        ALOGE("Unable to promote Layer handle");
        return false;
    }

    if (attachChildren()) {
        setTransactionFlags(eTransactionNeeded);
    }
    for (const sp<Layer>& child : mCurrentChildren) {
        newParent->addChild(child);
    }
    mCurrentChildren.clear();

    return true;
}

void Layer::setChildrenDrawingParent(const sp<Layer>& newParent) {
    for (const sp<Layer>& child : mDrawingChildren) {
        child->mDrawingParent = newParent;
        child->computeBounds(newParent->mBounds,
                             newParent->getTransformWithScale(
                                     newParent->getBufferScaleTransform()));
    }
}

bool Layer::reparent(const sp<IBinder>& newParentHandle) {
    bool callSetTransactionFlags = false;

    // While layers are detached, we allow most operations
    // and simply halt performing the actual transaction. However
    // for reparent != null we would enter the mRemovedFromCurrentState
    // state, regardless of whether doTransaction was called, and
    // so we need to prevent the update here.
    if (mLayerDetached && newParentHandle == nullptr) {
        return false;
    }

    sp<Layer> newParent;
    if (newParentHandle != nullptr) {
        auto handle = static_cast<Handle*>(newParentHandle.get());
        newParent = handle->owner.promote();
        if (newParent == nullptr) {
            ALOGE("Unable to promote Layer handle");
            return false;
        }
        if (newParent == this) {
            ALOGE("Invalid attempt to reparent Layer (%s) to itself", getName().c_str());
            return false;
        }
    }

    sp<Layer> parent = getParent();
    if (parent != nullptr) {
        parent->removeChild(this);
    }

    if (newParentHandle != nullptr) {
        newParent->addChild(this);
        if (!newParent->isRemovedFromCurrentState()) {
            addToCurrentState();
        } else {
            onRemovedFromCurrentState();
        }

        if (mLayerDetached) {
            mLayerDetached = false;
            callSetTransactionFlags = true;
        }
    } else {
        onRemovedFromCurrentState();
    }

    if (callSetTransactionFlags || attachChildren()) {
        setTransactionFlags(eTransactionNeeded);
    }
    return true;
}

bool Layer::detachChildren() {
    for (const sp<Layer>& child : mCurrentChildren) {
        sp<Client> parentClient = mClientRef.promote();
        sp<Client> client(child->mClientRef.promote());
        if (client != nullptr && parentClient != client) {
            child->mLayerDetached = true;
            child->detachChildren();
            child->removeRemoteSyncPoints();
        }
    }

    return true;
}

bool Layer::attachChildren() {
    bool changed = false;
    for (const sp<Layer>& child : mCurrentChildren) {
        sp<Client> parentClient = mClientRef.promote();
        sp<Client> client(child->mClientRef.promote());
        if (client != nullptr && parentClient != client) {
            if (child->mLayerDetached) {
                child->mLayerDetached = false;
                changed = true;
            }
            changed |= child->attachChildren();
        }
    }

    return changed;
}

bool Layer::setColorTransform(const mat4& matrix) {
    static const mat4 identityMatrix = mat4();

    if (mCurrentState.colorTransform == matrix) {
        return false;
    }
    ++mCurrentState.sequence;
    mCurrentState.colorTransform = matrix;
    mCurrentState.hasColorTransform = matrix != identityMatrix;
    mCurrentState.modified = true;
    setTransactionFlags(eTransactionNeeded);
    return true;
}

mat4 Layer::getColorTransform() const {
    mat4 colorTransform = mat4(getDrawingState().colorTransform);
    if (sp<Layer> parent = mDrawingParent.promote(); parent != nullptr) {
        colorTransform = parent->getColorTransform() * colorTransform;
    }
    return colorTransform;
}

bool Layer::hasColorTransform() const {
    bool hasColorTransform = getDrawingState().hasColorTransform;
    if (sp<Layer> parent = mDrawingParent.promote(); parent != nullptr) {
        hasColorTransform = hasColorTransform || parent->hasColorTransform();
    }
    return hasColorTransform;
}

bool Layer::isLegacyDataSpace() const {
    // return true when no higher bits are set
    return !(getDataSpace() &
             (ui::Dataspace::STANDARD_MASK | ui::Dataspace::TRANSFER_MASK |
              ui::Dataspace::RANGE_MASK));
}

void Layer::setParent(const sp<Layer>& layer) {
    mCurrentParent = layer;
}

int32_t Layer::getZ(LayerVector::StateSet stateSet) const {
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const State& state = useDrawing ? mDrawingState : mCurrentState;
    return state.z;
}

bool Layer::usingRelativeZ(LayerVector::StateSet stateSet) const {
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const State& state = useDrawing ? mDrawingState : mCurrentState;
    return state.isRelativeOf;
}

__attribute__((no_sanitize("unsigned-integer-overflow"))) LayerVector Layer::makeTraversalList(
        LayerVector::StateSet stateSet, bool* outSkipRelativeZUsers) {
    LOG_ALWAYS_FATAL_IF(stateSet == LayerVector::StateSet::Invalid,
                        "makeTraversalList received invalid stateSet");
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const LayerVector& children = useDrawing ? mDrawingChildren : mCurrentChildren;
    const State& state = useDrawing ? mDrawingState : mCurrentState;

    if (state.zOrderRelatives.size() == 0) {
        *outSkipRelativeZUsers = true;
        return children;
    }

    LayerVector traverse(stateSet);
    for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
        sp<Layer> strongRelative = weakRelative.promote();
        if (strongRelative != nullptr) {
            traverse.add(strongRelative);
        }
    }

    for (const sp<Layer>& child : children) {
        if (child->usingRelativeZ(stateSet)) {
            continue;
        }
        traverse.add(child);
    }

    return traverse;
}

/**
 * Negatively signed relatives are before 'this' in Z-order.
 */
void Layer::traverseInZOrder(LayerVector::StateSet stateSet, const LayerVector::Visitor& visitor) {
    // In the case we have other layers who are using a relative Z to us, makeTraversalList will
    // produce a new list for traversing, including our relatives, and not including our children
    // who are relatives of another surface. In the case that there are no relative Z,
    // makeTraversalList returns our children directly to avoid significant overhead.
    // However in this case we need to take the responsibility for filtering children which
    // are relatives of another surface here.
    bool skipRelativeZUsers = false;
    const LayerVector list = makeTraversalList(stateSet, &skipRelativeZUsers);

    size_t i = 0;
    for (; i < list.size(); i++) {
        const auto& relative = list[i];
        if (skipRelativeZUsers && relative->usingRelativeZ(stateSet)) {
            continue;
        }

        if (relative->getZ(stateSet) >= 0) {
            break;
        }
        relative->traverseInZOrder(stateSet, visitor);
    }

    visitor(this);
    for (; i < list.size(); i++) {
        const auto& relative = list[i];

        if (skipRelativeZUsers && relative->usingRelativeZ(stateSet)) {
            continue;
        }
        relative->traverseInZOrder(stateSet, visitor);
    }
}

/**
 * Positively signed relatives are before 'this' in reverse Z-order.
 */
void Layer::traverseInReverseZOrder(LayerVector::StateSet stateSet,
                                    const LayerVector::Visitor& visitor) {
    // See traverseInZOrder for documentation.
    bool skipRelativeZUsers = false;
    LayerVector list = makeTraversalList(stateSet, &skipRelativeZUsers);

    int32_t i = 0;
    for (i = int32_t(list.size()) - 1; i >= 0; i--) {
        const auto& relative = list[i];

        if (skipRelativeZUsers && relative->usingRelativeZ(stateSet)) {
            continue;
        }

        if (relative->getZ(stateSet) < 0) {
            break;
        }
        relative->traverseInReverseZOrder(stateSet, visitor);
    }
    visitor(this);
    for (; i >= 0; i--) {
        const auto& relative = list[i];

        if (skipRelativeZUsers && relative->usingRelativeZ(stateSet)) {
            continue;
        }

        relative->traverseInReverseZOrder(stateSet, visitor);
    }
}

LayerVector Layer::makeChildrenTraversalList(LayerVector::StateSet stateSet,
                                             const std::vector<Layer*>& layersInTree) {
    LOG_ALWAYS_FATAL_IF(stateSet == LayerVector::StateSet::Invalid,
                        "makeTraversalList received invalid stateSet");
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const LayerVector& children = useDrawing ? mDrawingChildren : mCurrentChildren;
    const State& state = useDrawing ? mDrawingState : mCurrentState;

    LayerVector traverse(stateSet);
    for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
        sp<Layer> strongRelative = weakRelative.promote();
        // Only add relative layers that are also descendents of the top most parent of the tree.
        // If a relative layer is not a descendent, then it should be ignored.
        if (std::binary_search(layersInTree.begin(), layersInTree.end(), strongRelative.get())) {
            traverse.add(strongRelative);
        }
    }

    for (const sp<Layer>& child : children) {
        const State& childState = useDrawing ? child->mDrawingState : child->mCurrentState;
        // If a layer has a relativeOf layer, only ignore if the layer it's relative to is a
        // descendent of the top most parent of the tree. If it's not a descendent, then just add
        // the child here since it won't be added later as a relative.
        if (std::binary_search(layersInTree.begin(), layersInTree.end(),
                               childState.zOrderRelativeOf.promote().get())) {
            continue;
        }
        traverse.add(child);
    }

    return traverse;
}

void Layer::traverseChildrenInZOrderInner(const std::vector<Layer*>& layersInTree,
                                          LayerVector::StateSet stateSet,
                                          const LayerVector::Visitor& visitor) {
    const LayerVector list = makeChildrenTraversalList(stateSet, layersInTree);

    size_t i = 0;
    for (; i < list.size(); i++) {
        const auto& relative = list[i];
        if (relative->getZ(stateSet) >= 0) {
            break;
        }
        relative->traverseChildrenInZOrderInner(layersInTree, stateSet, visitor);
    }

    visitor(this);
    for (; i < list.size(); i++) {
        const auto& relative = list[i];
        relative->traverseChildrenInZOrderInner(layersInTree, stateSet, visitor);
    }
}

std::vector<Layer*> Layer::getLayersInTree(LayerVector::StateSet stateSet) {
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const LayerVector& children = useDrawing ? mDrawingChildren : mCurrentChildren;

    std::vector<Layer*> layersInTree = {this};
    for (size_t i = 0; i < children.size(); i++) {
        const auto& child = children[i];
        std::vector<Layer*> childLayers = child->getLayersInTree(stateSet);
        layersInTree.insert(layersInTree.end(), childLayers.cbegin(), childLayers.cend());
    }

    return layersInTree;
}

void Layer::traverseChildrenInZOrder(LayerVector::StateSet stateSet,
                                     const LayerVector::Visitor& visitor) {
    std::vector<Layer*> layersInTree = getLayersInTree(stateSet);
    std::sort(layersInTree.begin(), layersInTree.end());
    traverseChildrenInZOrderInner(layersInTree, stateSet, visitor);
}

ui::Transform Layer::getTransform() const {
    return mEffectiveTransform;
}

half Layer::getAlpha() const {
    const auto& p = mDrawingParent.promote();

    half parentAlpha = (p != nullptr) ? p->getAlpha() : 1.0_hf;
    return parentAlpha * getDrawingState().color.a;
}

half4 Layer::getColor() const {
    const half4 color(getDrawingState().color);
    return half4(color.r, color.g, color.b, getAlpha());
}

Layer::RoundedCornerState Layer::getRoundedCornerState() const {
    const auto& p = mDrawingParent.promote();
    if (p != nullptr) {
        RoundedCornerState parentState = p->getRoundedCornerState();
        if (parentState.radius > 0) {
            ui::Transform t = getActiveTransform(getDrawingState());
            t = t.inverse();
            parentState.cropRect = t.transform(parentState.cropRect);
            // The rounded corners shader only accepts 1 corner radius for performance reasons,
            // but a transform matrix can define horizontal and vertical scales.
            // Let's take the average between both of them and pass into the shader, practically we
            // never do this type of transformation on windows anyway.
            parentState.radius *= (t[0][0] + t[1][1]) / 2.0f;
            return parentState;
        }
    }
    const float radius = getDrawingState().cornerRadius;
    return radius > 0 && getCrop(getDrawingState()).isValid()
            ? RoundedCornerState(getCrop(getDrawingState()).toFloatRect(), radius)
            : RoundedCornerState();
}

void Layer::commitChildList() {
    for (size_t i = 0; i < mCurrentChildren.size(); i++) {
        const auto& child = mCurrentChildren[i];
        child->commitChildList();
    }
    mDrawingChildren = mCurrentChildren;
    mDrawingParent = mCurrentParent;
}

static wp<Layer> extractLayerFromBinder(const wp<IBinder>& weakBinderHandle) {
    if (weakBinderHandle == nullptr) {
        return nullptr;
    }
    sp<IBinder> binderHandle = weakBinderHandle.promote();
    if (binderHandle == nullptr) {
        return nullptr;
    }
    sp<Layer::Handle> handle = static_cast<Layer::Handle*>(binderHandle.get());
    if (handle == nullptr) {
        return nullptr;
    }
    return handle->owner;
}

void Layer::setInputInfo(const InputWindowInfo& info) {
    mCurrentState.inputInfo = info;
    mCurrentState.touchableRegionCrop = extractLayerFromBinder(info.touchableRegionCropHandle);
    mCurrentState.modified = true;
    mCurrentState.inputInfoChanged = true;
    setTransactionFlags(eTransactionNeeded);
}

void Layer::writeToProtoDrawingState(LayerProto* layerInfo, uint32_t traceFlags) const {
    ui::Transform transform = getTransform();

    if (traceFlags & SurfaceTracing::TRACE_CRITICAL) {
        for (const auto& pendingState : mPendingStatesSnapshot) {
            auto barrierLayer = pendingState.barrierLayer_legacy.promote();
            if (barrierLayer != nullptr) {
                BarrierLayerProto* barrierLayerProto = layerInfo->add_barrier_layer();
                barrierLayerProto->set_id(barrierLayer->sequence);
                barrierLayerProto->set_frame_number(pendingState.frameNumber_legacy);
            }
        }

        auto buffer = getBuffer();
        if (buffer != nullptr) {
            LayerProtoHelper::writeToProto(buffer,
                                           [&]() { return layerInfo->mutable_active_buffer(); });
            LayerProtoHelper::writeToProto(ui::Transform(getBufferTransform()),
                                           layerInfo->mutable_buffer_transform());
        }
        layerInfo->set_invalidate(contentDirty);
        layerInfo->set_is_protected(isProtected());
        layerInfo->set_dataspace(dataspaceDetails(static_cast<android_dataspace>(getDataSpace())));
        layerInfo->set_queued_frames(getQueuedFrameCount());
        layerInfo->set_refresh_pending(isBufferLatched());
        layerInfo->set_curr_frame(mCurrentFrameNumber);
        layerInfo->set_effective_scaling_mode(getEffectiveScalingMode());

        layerInfo->set_corner_radius(getRoundedCornerState().radius);
        LayerProtoHelper::writeToProto(transform, layerInfo->mutable_transform());
        LayerProtoHelper::writePositionToProto(transform.tx(), transform.ty(),
                                               [&]() { return layerInfo->mutable_position(); });
        LayerProtoHelper::writeToProto(mBounds, [&]() { return layerInfo->mutable_bounds(); });
        LayerProtoHelper::writeToProto(debugGetVisibleRegionOnDefaultDisplay(),
                                       [&]() { return layerInfo->mutable_visible_region(); });
        LayerProtoHelper::writeToProto(surfaceDamageRegion,
                                       [&]() { return layerInfo->mutable_damage_region(); });
    }

    if (traceFlags & SurfaceTracing::TRACE_EXTRA) {
        LayerProtoHelper::writeToProto(mSourceBounds,
                                       [&]() { return layerInfo->mutable_source_bounds(); });
        LayerProtoHelper::writeToProto(mScreenBounds,
                                       [&]() { return layerInfo->mutable_screen_bounds(); });
    }
}

void Layer::writeToProtoCommonState(LayerProto* layerInfo, LayerVector::StateSet stateSet,
                                    uint32_t traceFlags) const {
    const bool useDrawing = stateSet == LayerVector::StateSet::Drawing;
    const LayerVector& children = useDrawing ? mDrawingChildren : mCurrentChildren;
    const State& state = useDrawing ? mDrawingState : mCurrentState;

    ui::Transform requestedTransform = state.active_legacy.transform;

    if (traceFlags & SurfaceTracing::TRACE_CRITICAL) {
        layerInfo->set_id(sequence);
        layerInfo->set_name(getName().c_str());
        layerInfo->set_type(getType());

        for (const auto& child : children) {
            layerInfo->add_children(child->sequence);
        }

        for (const wp<Layer>& weakRelative : state.zOrderRelatives) {
            sp<Layer> strongRelative = weakRelative.promote();
            if (strongRelative != nullptr) {
                layerInfo->add_relatives(strongRelative->sequence);
            }
        }

        LayerProtoHelper::writeToProto(state.activeTransparentRegion_legacy,
                                       [&]() { return layerInfo->mutable_transparent_region(); });

        layerInfo->set_layer_stack(getLayerStack());
        layerInfo->set_z(state.z);

        LayerProtoHelper::writePositionToProto(requestedTransform.tx(), requestedTransform.ty(),
                                               [&]() {
                                                   return layerInfo->mutable_requested_position();
                                               });

        LayerProtoHelper::writeSizeToProto(state.active_legacy.w, state.active_legacy.h,
                                           [&]() { return layerInfo->mutable_size(); });

        LayerProtoHelper::writeToProto(state.crop_legacy,
                                       [&]() { return layerInfo->mutable_crop(); });

        layerInfo->set_is_opaque(isOpaque(state));


        layerInfo->set_pixel_format(decodePixelFormat(getPixelFormat()));
        LayerProtoHelper::writeToProto(getColor(), [&]() { return layerInfo->mutable_color(); });
        LayerProtoHelper::writeToProto(state.color,
                                       [&]() { return layerInfo->mutable_requested_color(); });
        layerInfo->set_flags(state.flags);

        LayerProtoHelper::writeToProto(requestedTransform,
                                       layerInfo->mutable_requested_transform());

        auto parent = useDrawing ? mDrawingParent.promote() : mCurrentParent.promote();
        if (parent != nullptr) {
            layerInfo->set_parent(parent->sequence);
        } else {
            layerInfo->set_parent(-1);
        }

        auto zOrderRelativeOf = state.zOrderRelativeOf.promote();
        if (zOrderRelativeOf != nullptr) {
            layerInfo->set_z_order_relative_of(zOrderRelativeOf->sequence);
        } else {
            layerInfo->set_z_order_relative_of(-1);
        }
    }

    if (traceFlags & SurfaceTracing::TRACE_INPUT) {
        LayerProtoHelper::writeToProto(state.inputInfo, state.touchableRegionCrop,
                                       [&]() { return layerInfo->mutable_input_window_info(); });
    }

    if (traceFlags & SurfaceTracing::TRACE_EXTRA) {
        auto protoMap = layerInfo->mutable_metadata();
        for (const auto& entry : state.metadata.mMap) {
            (*protoMap)[entry.first] = std::string(entry.second.cbegin(), entry.second.cend());
        }
    }
}

bool Layer::isRemovedFromCurrentState() const  {
    return mRemovedFromCurrentState;
}

InputWindowInfo Layer::fillInputInfo() {
    InputWindowInfo info = mDrawingState.inputInfo;

    if (info.displayId == ADISPLAY_ID_NONE) {
        info.displayId = getLayerStack();
    }

    ui::Transform t = getTransform();
    const float xScale = t.sx();
    const float yScale = t.sy();
    int32_t xSurfaceInset = info.surfaceInset;
    int32_t ySurfaceInset = info.surfaceInset;
    if (xScale != 1.0f || yScale != 1.0f) {
        info.windowXScale *= (xScale != 0.0f) ? 1.0f / xScale : 0.0f;
        info.windowYScale *= (yScale != 0.0f) ? 1.0f / yScale : 0.0f;
        info.touchableRegion.scaleSelf(xScale, yScale);
        xSurfaceInset = std::round(xSurfaceInset * xScale);
        ySurfaceInset = std::round(ySurfaceInset * yScale);
    }

    // Transform layer size to screen space and inset it by surface insets.
    // If this is a portal window, set the touchableRegion to the layerBounds.
    Rect layerBounds = info.portalToDisplayId == ADISPLAY_ID_NONE
            ? getBufferSize(getDrawingState())
            : info.touchableRegion.getBounds();
    if (!layerBounds.isValid()) {
        layerBounds = getCroppedBufferSize(getDrawingState());
    }
    layerBounds = t.transform(layerBounds);

    // clamp inset to layer bounds
    xSurfaceInset = (xSurfaceInset >= 0) ? std::min(xSurfaceInset, layerBounds.getWidth() / 2) : 0;
    ySurfaceInset = (ySurfaceInset >= 0) ? std::min(ySurfaceInset, layerBounds.getHeight() / 2) : 0;

    layerBounds.inset(xSurfaceInset, ySurfaceInset, xSurfaceInset, ySurfaceInset);

    // Input coordinate should match the layer bounds.
    info.frameLeft = layerBounds.left;
    info.frameTop = layerBounds.top;
    info.frameRight = layerBounds.right;
    info.frameBottom = layerBounds.bottom;

    // Position the touchable region relative to frame screen location and restrict it to frame
    // bounds.
    info.touchableRegion = info.touchableRegion.translate(info.frameLeft, info.frameTop);
    info.visible = canReceiveInput();

    auto cropLayer = mDrawingState.touchableRegionCrop.promote();
    if (info.replaceTouchableRegionWithCrop) {
        if (cropLayer == nullptr) {
            info.touchableRegion = Region(Rect{mScreenBounds});
        } else {
            info.touchableRegion = Region(Rect{cropLayer->mScreenBounds});
        }
    } else if (cropLayer != nullptr) {
        info.touchableRegion = info.touchableRegion.intersect(Rect{cropLayer->mScreenBounds});
    }

    return info;
}

bool Layer::hasInput() const {
    return mDrawingState.inputInfo.token != nullptr;
}

std::shared_ptr<compositionengine::Layer> Layer::getCompositionLayer() const {
    return nullptr;
}

bool Layer::canReceiveInput() const {
    return !isHiddenByPolicy();
}

compositionengine::OutputLayer* Layer::findOutputLayerForDisplay(
        const sp<const DisplayDevice>& display) const {
    return display->getCompositionDisplay()->getOutputLayerForLayer(getCompositionLayer().get());
}

Region Layer::debugGetVisibleRegionOnDefaultDisplay() const {
    sp<DisplayDevice> displayDevice = mFlinger->getDefaultDisplayDeviceLocked();
    if (displayDevice == nullptr) {
        return {};
    }

    auto outputLayer = findOutputLayerForDisplay(displayDevice);
    if (outputLayer == nullptr) {
        return {};
    }

    return outputLayer->getState().visibleRegion;
}

void Layer::setInitialValuesForClone(const sp<Layer>& clonedFrom) {
    // copy drawing state from cloned layer
    mDrawingState = clonedFrom->mDrawingState;
    mClonedFrom = clonedFrom;

    // TODO: (b/140756730) Ignore input for now since InputDispatcher doesn't support multiple
    // InputWindows per client token yet.
    mDrawingState.inputInfo.token = nullptr;
}

void Layer::updateMirrorInfo() {
    if (mClonedChild == nullptr || !mClonedChild->isClonedFromAlive()) {
        // If mClonedChild is null, there is nothing to mirror. If isClonedFromAlive returns false,
        // it means that there is a clone, but the layer it was cloned from has been destroyed. In
        // that case, we want to delete the reference to the clone since we want it to get
        // destroyed. The root, this layer, will still be around since the client can continue
        // to hold a reference, but no cloned layers will be displayed.
        mClonedChild = nullptr;
        return;
    }

    std::map<sp<Layer>, sp<Layer>> clonedLayersMap;
    // If the real layer exists and is in current state, add the clone as a child of the root.
    // There's no need to remove from drawingState when the layer is offscreen since currentState is
    // copied to drawingState for the root layer. So the clonedChild is always removed from
    // drawingState and then needs to be added back each traversal.
    if (!mClonedChild->getClonedFrom()->isRemovedFromCurrentState()) {
        addChildToDrawing(mClonedChild);
    }

    mClonedChild->updateClonedDrawingState(clonedLayersMap);
    mClonedChild->updateClonedChildren(this, clonedLayersMap);
    mClonedChild->updateClonedRelatives(clonedLayersMap);
}

void Layer::updateClonedDrawingState(std::map<sp<Layer>, sp<Layer>>& clonedLayersMap) {
    // If the layer the clone was cloned from is alive, copy the content of the drawingState
    // to the clone. If the real layer is no longer alive, continue traversing the children
    // since we may be able to pull out other children that are still alive.
    if (isClonedFromAlive()) {
        sp<Layer> clonedFrom = getClonedFrom();
        mDrawingState = clonedFrom->mDrawingState;
        // TODO: (b/140756730) Ignore input for now since InputDispatcher doesn't support multiple
        // InputWindows per client token yet.
        mDrawingState.inputInfo.token = nullptr;
        clonedLayersMap.emplace(clonedFrom, this);
    }

    // The clone layer may have children in drawingState since they may have been created and
    // added from a previous request to updateMirorInfo. This is to ensure we don't recreate clones
    // that already exist, since we can just re-use them.
    // The drawingChildren will not get overwritten by the currentChildren since the clones are
    // not updated in the regular traversal. They are skipped since the root will lose the
    // reference to them when it copies its currentChildren to drawing.
    for (sp<Layer>& child : mDrawingChildren) {
        child->updateClonedDrawingState(clonedLayersMap);
    }
}

void Layer::updateClonedChildren(const sp<Layer>& mirrorRoot,
                                 std::map<sp<Layer>, sp<Layer>>& clonedLayersMap) {
    mDrawingChildren.clear();

    if (!isClonedFromAlive()) {
        return;
    }

    sp<Layer> clonedFrom = getClonedFrom();
    for (sp<Layer>& child : clonedFrom->mDrawingChildren) {
        if (child == mirrorRoot) {
            // This is to avoid cyclical mirroring.
            continue;
        }
        sp<Layer> clonedChild = clonedLayersMap[child];
        if (clonedChild == nullptr) {
            clonedChild = child->createClone();
            clonedLayersMap[child] = clonedChild;
        }
        addChildToDrawing(clonedChild);
        clonedChild->updateClonedChildren(mirrorRoot, clonedLayersMap);
    }
}

void Layer::updateClonedRelatives(std::map<sp<Layer>, sp<Layer>> clonedLayersMap) {
    mDrawingState.zOrderRelativeOf = nullptr;
    mDrawingState.zOrderRelatives.clear();

    if (!isClonedFromAlive()) {
        return;
    }

    sp<Layer> clonedFrom = getClonedFrom();
    for (wp<Layer>& relativeWeak : clonedFrom->mDrawingState.zOrderRelatives) {
        sp<Layer> relative = relativeWeak.promote();
        auto clonedRelative = clonedLayersMap[relative];
        if (clonedRelative != nullptr) {
            mDrawingState.zOrderRelatives.add(clonedRelative);
        }
    }

    // Check if the relativeLayer for the real layer is part of the cloned hierarchy.
    // It's possible that the layer it's relative to is outside the requested cloned hierarchy.
    // In that case, we treat the layer as if the relativeOf has been removed. This way, it will
    // still traverse the children, but the layer with the missing relativeOf will not be shown
    // on screen.
    sp<Layer> relativeOf = clonedFrom->mDrawingState.zOrderRelativeOf.promote();
    sp<Layer> clonedRelativeOf = clonedLayersMap[relativeOf];
    if (clonedRelativeOf != nullptr) {
        mDrawingState.zOrderRelativeOf = clonedRelativeOf;
    }

    for (sp<Layer>& child : mDrawingChildren) {
        child->updateClonedRelatives(clonedLayersMap);
    }
}

void Layer::addChildToDrawing(const sp<Layer>& layer) {
    mDrawingChildren.add(layer);
    layer->mDrawingParent = this;
}

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

}; // 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