/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=2 et tw=80 : */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "CompositorParent.h"
#include <stdio.h>                      // for fprintf, stdout
#include <stdint.h>                     // for uint64_t
#include <map>                          // for _Rb_tree_iterator, etc
#include <utility>                      // for pair
#include "LayerTransactionParent.h"     // for LayerTransactionParent
#include "RenderTrace.h"                // for RenderTraceLayers
#include "base/message_loop.h"          // for MessageLoop
#include "base/process.h"               // for ProcessHandle
#include "base/process_util.h"          // for OpenProcessHandle
#include "base/task.h"                  // for CancelableTask, etc
#include "base/thread.h"                // for Thread
#include "base/tracked.h"               // for FROM_HERE
#include "gfxContext.h"                 // for gfxContext
#include "gfxPlatform.h"                // for gfxPlatform
#include "gfxPrefs.h"                   // for gfxPrefs
#include "ipc/ShadowLayersManager.h"    // for ShadowLayersManager
#include "mozilla/AutoRestore.h"        // for AutoRestore
#include "mozilla/DebugOnly.h"          // for DebugOnly
#include "mozilla/gfx/2D.h"          // for DrawTarget
#include "mozilla/gfx/Point.h"          // for IntSize
#include "mozilla/ipc/Transport.h"      // for Transport
#include "mozilla/layers/APZCTreeManager.h"  // for APZCTreeManager
#include "mozilla/layers/AsyncCompositionManager.h"
#include "mozilla/layers/BasicCompositor.h"  // for BasicCompositor
#include "mozilla/layers/Compositor.h"  // for Compositor
#include "mozilla/layers/CompositorOGL.h"  // for CompositorOGL
#include "mozilla/layers/CompositorTypes.h"
#include "mozilla/layers/LayerManagerComposite.h"
#include "mozilla/layers/LayersTypes.h"
#include "mozilla/layers/PLayerTransactionParent.h"
#include "mozilla/mozalloc.h"           // for operator new, etc
#include "nsCOMPtr.h"                   // for already_AddRefed
#include "nsDebug.h"                    // for NS_ABORT_IF_FALSE, etc
#include "nsISupportsImpl.h"            // for MOZ_COUNT_CTOR, etc
#include "nsIWidget.h"                  // for nsIWidget
#include "nsRect.h"                     // for nsIntRect
#include "nsTArray.h"                   // for nsTArray
#include "nsThreadUtils.h"              // for NS_IsMainThread
#include "nsXULAppAPI.h"                // for XRE_GetIOMessageLoop
#ifdef XP_WIN
#include "mozilla/layers/CompositorD3D11.h"
#include "mozilla/layers/CompositorD3D9.h"
#endif
#include "GeckoProfiler.h"
#include "mozilla/ipc/ProtocolTypes.h"
#include "mozilla/unused.h"
#include "mozilla/Hal.h"
#include "mozilla/HalTypes.h"

namespace mozilla {
namespace layers {

using namespace base;
using namespace mozilla::ipc;
using namespace mozilla::gfx;
using namespace std;

CompositorParent::LayerTreeState::LayerTreeState()
  : mParent(nullptr)
  , mLayerManager(nullptr)
  , mCrossProcessParent(nullptr)
{
}

typedef map<uint64_t, CompositorParent::LayerTreeState> LayerTreeMap;
static LayerTreeMap sIndirectLayerTrees;

// FIXME/bug 774386: we're assuming that there's only one
// CompositorParent, but that's not always true.  This assumption only
// affects CrossProcessCompositorParent below.
static Thread* sCompositorThread = nullptr;
// manual reference count of the compositor thread.
static int sCompositorThreadRefCount = 0;
static MessageLoop* sMainLoop = nullptr;
// When ContentParent::StartUp() is called, we use the Thread global.
// When StartUpWithExistingThread() is used, we have to use the two
// duplicated globals, because there's no API to make a Thread from an
// existing thread.
static PlatformThreadId sCompositorThreadID = 0;
static MessageLoop* sCompositorLoop = nullptr;

// See ImageBridgeChild.cpp
void ReleaseImageBridgeParentSingleton();

static void DeferredDeleteCompositorParent(CompositorParent* aNowReadyToDie)
{
  aNowReadyToDie->Release();
}

static void DeleteCompositorThread()
{
  if (NS_IsMainThread()){
    ReleaseImageBridgeParentSingleton();
    delete sCompositorThread;
    sCompositorThread = nullptr;
    sCompositorLoop = nullptr;
    sCompositorThreadID = 0;
  } else {
    sMainLoop->PostTask(FROM_HERE, NewRunnableFunction(&DeleteCompositorThread));
  }
}

static void ReleaseCompositorThread()
{
  if(--sCompositorThreadRefCount == 0) {
    DeleteCompositorThread();
  }
}

static void SetThreadPriority()
{
  hal::SetCurrentThreadPriority(hal::THREAD_PRIORITY_COMPOSITOR);
}

void
CompositorParent::StartUpWithExistingThread(MessageLoop* aMsgLoop,
                                            PlatformThreadId aThreadID)
{
  MOZ_ASSERT(!sCompositorThread);
  CreateCompositorMap();
  sCompositorLoop = aMsgLoop;
  sCompositorThreadID = aThreadID;
  sMainLoop = MessageLoop::current();
  sCompositorThreadRefCount = 1;
}

void CompositorParent::StartUp()
{
  // Check if compositor started already with StartUpWithExistingThread
  if (sCompositorThreadID) {
    return;
  }
  MOZ_ASSERT(!sCompositorLoop);
  CreateCompositorMap();
  CreateThread();
  sMainLoop = MessageLoop::current();
}

void CompositorParent::ShutDown()
{
  DestroyThread();
  DestroyCompositorMap();
}

bool CompositorParent::CreateThread()
{
  NS_ASSERTION(NS_IsMainThread(), "Should be on the main Thread!");
  if (sCompositorThread || sCompositorLoop) {
    return true;
  }
  sCompositorThreadRefCount = 1;
  sCompositorThread = new Thread("Compositor");

  Thread::Options options;
  /* Timeout values are powers-of-two to enable us get better data.
     128ms is chosen for transient hangs because 8Hz should be the minimally
     acceptable goal for Compositor responsiveness (normal goal is 60Hz). */
  options.transient_hang_timeout = 128; // milliseconds
  /* 8192ms is chosen for permanent hangs because it's several seconds longer
     than the default hang timeout on major platforms (about 5 seconds). */
  options.permanent_hang_timeout = 8192; // milliseconds

  if (!sCompositorThread->StartWithOptions(options)) {
    delete sCompositorThread;
    sCompositorThread = nullptr;
    return false;
  }

  return true;
}

void CompositorParent::DestroyThread()
{
  NS_ASSERTION(NS_IsMainThread(), "Should be on the main Thread!");
  ReleaseCompositorThread();
}

MessageLoop* CompositorParent::CompositorLoop()
{
  return sCompositorThread ? sCompositorThread->message_loop() : sCompositorLoop;
}

CompositorParent::CompositorParent(nsIWidget* aWidget,
                                   bool aUseExternalSurfaceSize,
                                   int aSurfaceWidth, int aSurfaceHeight)
  : mWidget(aWidget)
  , mCurrentCompositeTask(nullptr)
  , mIsTesting(false)
  , mPaused(false)
  , mUseExternalSurfaceSize(aUseExternalSurfaceSize)
  , mEGLSurfaceSize(aSurfaceWidth, aSurfaceHeight)
  , mPauseCompositionMonitor("PauseCompositionMonitor")
  , mResumeCompositionMonitor("ResumeCompositionMonitor")
  , mOverrideComposeReadiness(false)
  , mForceCompositionTask(nullptr)
  , mWantDidCompositeEvent(false)
{
  NS_ABORT_IF_FALSE(sCompositorThread != nullptr || sCompositorThreadID,
                    "The compositor thread must be Initialized before instanciating a COmpositorParent.");
  MOZ_COUNT_CTOR(CompositorParent);
  mCompositorID = 0;
  // FIXME: This holds on the the fact that right now the only thing that
  // can destroy this instance is initialized on the compositor thread after
  // this task has been processed.
  CompositorLoop()->PostTask(FROM_HERE, NewRunnableFunction(&AddCompositor,
                                                          this, &mCompositorID));

  CompositorLoop()->PostTask(FROM_HERE, NewRunnableFunction(SetThreadPriority));

  mRootLayerTreeID = AllocateLayerTreeId();
  sIndirectLayerTrees[mRootLayerTreeID].mParent = this;

  mApzcTreeManager = new APZCTreeManager();
  ++sCompositorThreadRefCount;
}

PlatformThreadId
CompositorParent::CompositorThreadID()
{
  return sCompositorThread ? sCompositorThread->thread_id() : sCompositorThreadID;
}

bool
CompositorParent::IsInCompositorThread()
{
  return CompositorThreadID() == PlatformThread::CurrentId();
}

uint64_t
CompositorParent::RootLayerTreeId()
{
  return mRootLayerTreeID;
}

CompositorParent::~CompositorParent()
{
  MOZ_COUNT_DTOR(CompositorParent);

  ReleaseCompositorThread();
}

void
CompositorParent::Destroy()
{
  NS_ABORT_IF_FALSE(ManagedPLayerTransactionParent().Length() == 0,
                    "CompositorParent destroyed before managed PLayerTransactionParent");

  // Ensure that the layer manager is destructed on the compositor thread.
  mLayerManager = nullptr;
  if (mCompositor) {
    mCompositor->Destroy();
  }
  mCompositor = nullptr;

  mCompositionManager = nullptr;
  mApzcTreeManager->ClearTree();
  mApzcTreeManager = nullptr;
  sIndirectLayerTrees.erase(mRootLayerTreeID);
}

void
CompositorParent::ForceIsFirstPaint()
{
  mCompositionManager->ForceIsFirstPaint();
}

bool
CompositorParent::RecvWillStop()
{
  mPaused = true;
  RemoveCompositor(mCompositorID);

  // Ensure that the layer manager is destroyed before CompositorChild.
  if (mLayerManager) {
    for (LayerTreeMap::iterator it = sIndirectLayerTrees.begin();
         it != sIndirectLayerTrees.end(); it++)
    {
      LayerTreeState* lts = &it->second;
      if (lts->mParent == this) {
        mLayerManager->ClearCachedResources(lts->mRoot);
        lts->mLayerManager = nullptr;
      }
    }
    mLayerManager->Destroy();
    mLayerManager = nullptr;
    mCompositionManager = nullptr;
  }

  return true;
}

bool
CompositorParent::RecvStop()
{
  Destroy();
  // There are chances that the ref count reaches zero on the main thread shortly
  // after this function returns while some ipdl code still needs to run on
  // this thread.
  // We must keep the compositor parent alive untill the code handling message
  // reception is finished on this thread.
  this->AddRef(); // Corresponds to DeferredDeleteCompositorParent's Release
  CompositorLoop()->PostTask(FROM_HERE,
                           NewRunnableFunction(&DeferredDeleteCompositorParent,
                                               this));
  return true;
}

bool
CompositorParent::RecvPause()
{
  PauseComposition();
  return true;
}

bool
CompositorParent::RecvResume()
{
  ResumeComposition();
  return true;
}

bool
CompositorParent::RecvMakeSnapshot(const SurfaceDescriptor& aInSnapshot,
                                   SurfaceDescriptor* aOutSnapshot)
{
  RefPtr<DrawTarget> target = GetDrawTargetForDescriptor(aInSnapshot, gfx::BackendType::CAIRO);
  ForceComposeToTarget(target);
  *aOutSnapshot = aInSnapshot;
  return true;
}

bool
CompositorParent::RecvFlushRendering()
{
  // If we're waiting to do a composite, then cancel it
  // and do it immediately instead.
  if (mCurrentCompositeTask) {
    CancelCurrentCompositeTask();
    ForceComposeToTarget(nullptr);
  }
  return true;
}

bool
CompositorParent::RecvNotifyRegionInvalidated(const nsIntRegion& aRegion)
{
  if (mLayerManager) {
    mLayerManager->AddInvalidRegion(aRegion);
  }
  return true;
}

bool
CompositorParent::RecvStartFrameTimeRecording(const int32_t& aBufferSize, uint32_t* aOutStartIndex)
{
  if (mLayerManager) {
    *aOutStartIndex = mLayerManager->StartFrameTimeRecording(aBufferSize);
  } else {
    *aOutStartIndex = 0;
  }
  return true;
}

bool
CompositorParent::RecvStopFrameTimeRecording(const uint32_t& aStartIndex,
                                             InfallibleTArray<float>* intervals)
{
  if (mLayerManager) {
    mLayerManager->StopFrameTimeRecording(aStartIndex, *intervals);
  }
  return true;
}

void
CompositorParent::ActorDestroy(ActorDestroyReason why)
{
  CancelCurrentCompositeTask();
  if (mForceCompositionTask) {
    mForceCompositionTask->Cancel();
    mForceCompositionTask = nullptr;
  }
  mPaused = true;
  RemoveCompositor(mCompositorID);

  if (mLayerManager) {
    mLayerManager->Destroy();
    mLayerManager = nullptr;
    sIndirectLayerTrees[mRootLayerTreeID].mLayerManager = nullptr;
    mCompositionManager = nullptr;
    mCompositor = nullptr;
  }
}


void
CompositorParent::ScheduleRenderOnCompositorThread()
{
  CancelableTask *renderTask = NewRunnableMethod(this, &CompositorParent::ScheduleComposition);
  CompositorLoop()->PostTask(FROM_HERE, renderTask);
}

void
CompositorParent::PauseComposition()
{
  NS_ABORT_IF_FALSE(CompositorThreadID() == PlatformThread::CurrentId(),
                    "PauseComposition() can only be called on the compositor thread");

  MonitorAutoLock lock(mPauseCompositionMonitor);

  if (!mPaused) {
    mPaused = true;

    mCompositor->Pause();
  }

  // if anyone's waiting to make sure that composition really got paused, tell them
  lock.NotifyAll();
}

void
CompositorParent::ResumeComposition()
{
  NS_ABORT_IF_FALSE(CompositorThreadID() == PlatformThread::CurrentId(),
                    "ResumeComposition() can only be called on the compositor thread");

  MonitorAutoLock lock(mResumeCompositionMonitor);

  if (!mCompositor->Resume()) {
#ifdef MOZ_WIDGET_ANDROID
    // We can't get a surface. This could be because the activity changed between
    // the time resume was scheduled and now.
    __android_log_print(ANDROID_LOG_INFO, "CompositorParent", "Unable to renew compositor surface; remaining in paused state");
#endif
    lock.NotifyAll();
    return;
  }

  mPaused = false;

  Composite();

  // if anyone's waiting to make sure that composition really got resumed, tell them
  lock.NotifyAll();
}

void
CompositorParent::ForceComposition()
{
  // Cancel the orientation changed state to force composition
  mForceCompositionTask = nullptr;
  ScheduleRenderOnCompositorThread();
}

void
CompositorParent::CancelCurrentCompositeTask()
{
  if (mCurrentCompositeTask) {
    mCurrentCompositeTask->Cancel();
    mCurrentCompositeTask = nullptr;
  }
}

void
CompositorParent::SetEGLSurfaceSize(int width, int height)
{
  NS_ASSERTION(mUseExternalSurfaceSize, "Compositor created without UseExternalSurfaceSize provided");
  mEGLSurfaceSize.SizeTo(width, height);
  if (mCompositor) {
    mCompositor->SetDestinationSurfaceSize(gfx::IntSize(mEGLSurfaceSize.width, mEGLSurfaceSize.height));
  }
}

void
CompositorParent::ResumeCompositionAndResize(int width, int height)
{
  SetEGLSurfaceSize(width, height);
  ResumeComposition();
}

/*
 * This will execute a pause synchronously, waiting to make sure that the compositor
 * really is paused.
 */
void
CompositorParent::SchedulePauseOnCompositorThread()
{
  MonitorAutoLock lock(mPauseCompositionMonitor);

  CancelableTask *pauseTask = NewRunnableMethod(this,
                                                &CompositorParent::PauseComposition);
  CompositorLoop()->PostTask(FROM_HERE, pauseTask);

  // Wait until the pause has actually been processed by the compositor thread
  lock.Wait();
}

bool
CompositorParent::ScheduleResumeOnCompositorThread(int width, int height)
{
  MonitorAutoLock lock(mResumeCompositionMonitor);

  CancelableTask *resumeTask =
    NewRunnableMethod(this, &CompositorParent::ResumeCompositionAndResize, width, height);
  CompositorLoop()->PostTask(FROM_HERE, resumeTask);

  // Wait until the resume has actually been processed by the compositor thread
  lock.Wait();

  return !mPaused;
}

void
CompositorParent::ScheduleTask(CancelableTask* task, int time)
{
  if (time == 0) {
    MessageLoop::current()->PostTask(FROM_HERE, task);
  } else {
    MessageLoop::current()->PostDelayedTask(FROM_HERE, task, time);
  }
}

void
CompositorParent::NotifyShadowTreeTransaction(uint64_t aId, bool aIsFirstPaint,
    bool aScheduleComposite, uint32_t aPaintSequenceNumber)
{
  if (mApzcTreeManager &&
      mLayerManager &&
      mLayerManager->GetRoot()) {
    AutoResolveRefLayers resolve(mCompositionManager);
    mApzcTreeManager->UpdatePanZoomControllerTree(this, mLayerManager->GetRoot(),
        aIsFirstPaint, aId, aPaintSequenceNumber);

    mLayerManager->NotifyShadowTreeTransaction();
  }
  if (aScheduleComposite) {
    ScheduleComposition();
  }

  mWantDidCompositeEvent = true;
}

// Used when layout.frame_rate is -1. Needs to be kept in sync with
// DEFAULT_FRAME_RATE in nsRefreshDriver.cpp.
static const int32_t kDefaultFrameRate = 60;

static int32_t
CalculateCompositionFrameRate()
{
  int32_t compositionFrameRatePref = gfxPrefs::LayersCompositionFrameRate();
  if (compositionFrameRatePref < 0) {
    // Use the same frame rate for composition as for layout.
    int32_t layoutFrameRatePref = gfxPrefs::LayoutFrameRate();
    if (layoutFrameRatePref < 0) {
      // TODO: The main thread frame scheduling code consults the actual
      // monitor refresh rate in this case. We should do the same.
      return kDefaultFrameRate;
    }
    return layoutFrameRatePref;
  }
  return compositionFrameRatePref;
}

void
CompositorParent::ScheduleComposition()
{
  if (mCurrentCompositeTask || mPaused) {
    return;
  }

  bool initialComposition = mLastCompose.IsNull();
  TimeDuration delta;
  if (!initialComposition)
    delta = TimeStamp::Now() - mLastCompose;

  int32_t rate = CalculateCompositionFrameRate();

  // If rate == 0 (ASAP mode), minFrameDelta must be 0 so there's no delay.
  TimeDuration minFrameDelta = TimeDuration::FromMilliseconds(
    rate == 0 ? 0.0 : std::max(0.0, 1000.0 / rate));


  mCurrentCompositeTask = NewRunnableMethod(this, &CompositorParent::Composite);

  if (!initialComposition && delta < minFrameDelta) {
    TimeDuration delay = minFrameDelta - delta;
#ifdef COMPOSITOR_PERFORMANCE_WARNING
    mExpectedComposeStartTime = TimeStamp::Now() + delay;
#endif
    ScheduleTask(mCurrentCompositeTask, delay.ToMilliseconds());
  } else {
#ifdef COMPOSITOR_PERFORMANCE_WARNING
    mExpectedComposeStartTime = TimeStamp::Now();
#endif
    ScheduleTask(mCurrentCompositeTask, 0);
  }
}

void
CompositorParent::Composite()
{
  CompositeToTarget(nullptr);
}

void
CompositorParent::CompositeToTarget(DrawTarget* aTarget)
{
  profiler_tracing("Paint", "Composite", TRACING_INTERVAL_START);
  PROFILER_LABEL("CompositorParent", "Composite");
  NS_ABORT_IF_FALSE(CompositorThreadID() == PlatformThread::CurrentId(),
                    "Composite can only be called on the compositor thread");

#ifdef COMPOSITOR_PERFORMANCE_WARNING
  TimeDuration scheduleDelta = TimeStamp::Now() - mExpectedComposeStartTime;
  if (scheduleDelta > TimeDuration::FromMilliseconds(2) ||
      scheduleDelta < TimeDuration::FromMilliseconds(-2)) {
    printf_stderr("Compositor: Compose starting off schedule by %4.1f ms\n",
                  scheduleDelta.ToMilliseconds());
  }
#endif

  if (mCurrentCompositeTask) {
    mCurrentCompositeTask->Cancel();
    mCurrentCompositeTask = nullptr;
  }

  mLastCompose = TimeStamp::Now();

  if (!CanComposite()) {
    return;
  }

  AutoResolveRefLayers resolve(mCompositionManager);

  if (aTarget) {
    mLayerManager->BeginTransactionWithDrawTarget(aTarget);
  } else {
    mLayerManager->BeginTransaction();
  }

  if (mForceCompositionTask && !mOverrideComposeReadiness) {
    if (mCompositionManager->ReadyForCompose()) {
      mForceCompositionTask->Cancel();
      mForceCompositionTask = nullptr;
    } else {
      return;
    }
  }

  TimeStamp time = mIsTesting ? mTestTime : mLastCompose;
  bool requestNextFrame = mCompositionManager->TransformShadowTree(time);
  if (requestNextFrame) {
    ScheduleComposition();
  }

  RenderTraceLayers(mLayerManager->GetRoot(), "0000");

  mCompositionManager->ComputeRotation();

#ifdef MOZ_DUMP_PAINTING
  static bool gDumpCompositorTree = false;
  if (gDumpCompositorTree) {
    printf_stderr("Painting --- compositing layer tree:\n");
    mLayerManager->Dump();
  }
#endif
  mLayerManager->SetDebugOverlayWantsNextFrame(false);
  mLayerManager->EndEmptyTransaction();

  if (!aTarget && mWantDidCompositeEvent) {
    DidComposite();
    mWantDidCompositeEvent = false;
  }

  if (mLayerManager->DebugOverlayWantsNextFrame()) {
    ScheduleComposition();
  }

#ifdef COMPOSITOR_PERFORMANCE_WARNING
  TimeDuration executionTime = TimeStamp::Now() - mLastCompose;
  TimeDuration frameBudget = TimeDuration::FromMilliseconds(15);
  int32_t frameRate = CalculateCompositionFrameRate();
  if (frameRate > 0) {
    frameBudget = TimeDuration::FromSeconds(1.0 / frameRate);
  }
  if (executionTime > frameBudget) {
    printf_stderr("Compositor: Composite execution took %4.1f ms\n",
                  executionTime.ToMilliseconds());
  }
#endif

  // 0 -> Full-tilt composite
  if (gfxPrefs::LayersCompositionFrameRate() == 0
    || mLayerManager->GetCompositor()->GetDiagnosticTypes() & DiagnosticTypes::FLASH_BORDERS) {
    // Special full-tilt composite mode for performance testing
    ScheduleComposition();
  }

  profiler_tracing("Paint", "Composite", TRACING_INTERVAL_END);
}

void
CompositorParent::DidComposite()
{
  unused << SendDidComposite(0);

  for (LayerTreeMap::iterator it = sIndirectLayerTrees.begin();
       it != sIndirectLayerTrees.end(); it++) {
    LayerTreeState* lts = &it->second;
    if (lts->mParent == this && lts->mCrossProcessParent) {
      unused << lts->mCrossProcessParent->SendDidComposite(it->first);
    }
  }
}

void
CompositorParent::ForceComposeToTarget(DrawTarget* aTarget)
{
  PROFILER_LABEL("CompositorParent", "ForceComposeToTarget");
  AutoRestore<bool> override(mOverrideComposeReadiness);
  mOverrideComposeReadiness = true;

  CompositeToTarget(aTarget);
}

bool
CompositorParent::CanComposite()
{
  return !(mPaused || !mLayerManager || !mLayerManager->GetRoot());
}

// Go down the composite layer tree, setting properties to match their
// content-side counterparts.
static void
SetShadowProperties(Layer* aLayer)
{
  // FIXME: Bug 717688 -- Do these updates in LayerTransactionParent::RecvUpdate.
  LayerComposite* layerComposite = aLayer->AsLayerComposite();
  // Set the layerComposite's base transform to the layer's base transform.
  layerComposite->SetShadowTransform(aLayer->GetBaseTransform());
  layerComposite->SetShadowTransformSetByAnimation(false);
  layerComposite->SetShadowVisibleRegion(aLayer->GetVisibleRegion());
  layerComposite->SetShadowClipRect(aLayer->GetClipRect());
  layerComposite->SetShadowOpacity(aLayer->GetOpacity());

  for (Layer* child = aLayer->GetFirstChild();
      child; child = child->GetNextSibling()) {
    SetShadowProperties(child);
  }
}

void
CompositorParent::ScheduleRotationOnCompositorThread(const TargetConfig& aTargetConfig,
                                                     bool aIsFirstPaint)
{
  MOZ_ASSERT(IsInCompositorThread());

  if (!aIsFirstPaint &&
      !mCompositionManager->IsFirstPaint() &&
      mCompositionManager->RequiresReorientation(aTargetConfig.orientation())) {
    if (mForceCompositionTask != nullptr) {
      mForceCompositionTask->Cancel();
    }
    mForceCompositionTask = NewRunnableMethod(this, &CompositorParent::ForceComposition);
    ScheduleTask(mForceCompositionTask, gfxPrefs::OrientationSyncMillis());
  }
}

void
CompositorParent::ShadowLayersUpdated(LayerTransactionParent* aLayerTree,
                                      const TargetConfig& aTargetConfig,
                                      bool aIsFirstPaint,
                                      bool aScheduleComposite,
                                      uint32_t aPaintSequenceNumber)
{
  ScheduleRotationOnCompositorThread(aTargetConfig, aIsFirstPaint);

  // Instruct the LayerManager to update its render bounds now. Since all the orientation
  // change, dimension change would be done at the stage, update the size here is free of
  // race condition.
  mLayerManager->UpdateRenderBounds(aTargetConfig.clientBounds());
  mLayerManager->SetRegionToClear(aTargetConfig.clearRegion());

  mCompositionManager->Updated(aIsFirstPaint, aTargetConfig);
  Layer* root = aLayerTree->GetRoot();
  mLayerManager->SetRoot(root);

  if (mApzcTreeManager) {
    AutoResolveRefLayers resolve(mCompositionManager);
    mApzcTreeManager->UpdatePanZoomControllerTree(this, root, aIsFirstPaint,
        mRootLayerTreeID, aPaintSequenceNumber);
  }

  if (root) {
    SetShadowProperties(root);
  }
  if (aScheduleComposite) {
    ScheduleComposition();
    // When testing we synchronously update the shadow tree with the animated
    // values to avoid race conditions when calling GetAnimationTransform etc.
    // (since the above SetShadowProperties will remove animation effects).
    // However, we only do this update when a composite operation is already
    // scheduled in order to better match the behavior under regular sampling
    // conditions.
    if (mIsTesting && root && mCurrentCompositeTask) {
      AutoResolveRefLayers resolve(mCompositionManager);
      bool requestNextFrame =
        mCompositionManager->TransformShadowTree(mTestTime);
      if (!requestNextFrame) {
        CancelCurrentCompositeTask();
      }
    }
  }
  mLayerManager->NotifyShadowTreeTransaction();
  mWantDidCompositeEvent = true;
}

void
CompositorParent::ForceComposite(LayerTransactionParent* aLayerTree)
{
  ScheduleComposition();
}

bool
CompositorParent::SetTestSampleTime(LayerTransactionParent* aLayerTree,
                                    const TimeStamp& aTime)
{
  if (aTime.IsNull()) {
    return false;
  }

  mIsTesting = true;
  mTestTime = aTime;

  // Update but only if we were already scheduled to animate
  if (mCompositionManager && mCurrentCompositeTask) {
    AutoResolveRefLayers resolve(mCompositionManager);
    bool requestNextFrame = mCompositionManager->TransformShadowTree(aTime);
    if (!requestNextFrame) {
      CancelCurrentCompositeTask();
    }
  }

  return true;
}

void
CompositorParent::LeaveTestMode(LayerTransactionParent* aLayerTree)
{
  mIsTesting = false;
}

bool
CompositorParent::RecvRequestOverfill()
{
  uint32_t overfillRatio = mCompositor->GetFillRatio();
  unused << SendOverfill(overfillRatio);
  return true;
}

void
CompositorParent::GetAPZTestData(const LayerTransactionParent* aLayerTree,
                                 APZTestData* aOutData)
{
  *aOutData = sIndirectLayerTrees[mRootLayerTreeID].mApzTestData;
}


void
CompositorParent::InitializeLayerManager(const nsTArray<LayersBackend>& aBackendHints)
{
  NS_ASSERTION(!mLayerManager, "Already initialised mLayerManager");
  NS_ASSERTION(!mCompositor,   "Already initialised mCompositor");

  for (size_t i = 0; i < aBackendHints.Length(); ++i) {
    RefPtr<Compositor> compositor;
    if (aBackendHints[i] == LayersBackend::LAYERS_OPENGL) {
      compositor = new CompositorOGL(mWidget,
                                     mEGLSurfaceSize.width,
                                     mEGLSurfaceSize.height,
                                     mUseExternalSurfaceSize);
    } else if (aBackendHints[i] == LayersBackend::LAYERS_BASIC) {
      compositor = new BasicCompositor(mWidget);
#ifdef XP_WIN
    } else if (aBackendHints[i] == LayersBackend::LAYERS_D3D11) {
      compositor = new CompositorD3D11(mWidget);
    } else if (aBackendHints[i] == LayersBackend::LAYERS_D3D9) {
      compositor = new CompositorD3D9(this, mWidget);
#endif
    }

    if (!compositor) {
      // We passed a backend hint for which we can't create a compositor.
      // For example, we sometime pass LayersBackend::LAYERS_NONE as filler in aBackendHints.
      continue;
    }

    compositor->SetCompositorID(mCompositorID);
    RefPtr<LayerManagerComposite> layerManager = new LayerManagerComposite(compositor);

    if (layerManager->Initialize()) {
      mLayerManager = layerManager;
      MOZ_ASSERT(compositor);
      mCompositor = compositor;
      sIndirectLayerTrees[mRootLayerTreeID].mLayerManager = layerManager;
      return;
    }
  }
}

PLayerTransactionParent*
CompositorParent::AllocPLayerTransactionParent(const nsTArray<LayersBackend>& aBackendHints,
                                               const uint64_t& aId,
                                               TextureFactoryIdentifier* aTextureFactoryIdentifier,
                                               bool *aSuccess)
{
  MOZ_ASSERT(aId == 0);

  // mWidget doesn't belong to the compositor thread, so it should be set to
  // nullptr before returning from this method, to avoid accessing it elsewhere.
  nsIntRect rect;
  mWidget->GetClientBounds(rect);
  InitializeLayerManager(aBackendHints);
  mWidget = nullptr;

  if (!mLayerManager) {
    NS_WARNING("Failed to initialise Compositor");
    *aSuccess = false;
    LayerTransactionParent* p = new LayerTransactionParent(nullptr, this, 0,
                                                           // child side's process id is current process Id
                                                           base::GetProcId(base::GetCurrentProcessHandle()));
    p->AddIPDLReference();
    return p;
  }

  mCompositionManager = new AsyncCompositionManager(mLayerManager);
  *aSuccess = true;

  *aTextureFactoryIdentifier = mCompositor->GetTextureFactoryIdentifier();
  LayerTransactionParent* p = new LayerTransactionParent(mLayerManager, this, 0,
                                                         // child side's process id is current process Id
                                                         base::GetProcId(base::GetCurrentProcessHandle()));
  p->AddIPDLReference();
  return p;
}

bool
CompositorParent::DeallocPLayerTransactionParent(PLayerTransactionParent* actor)
{
  static_cast<LayerTransactionParent*>(actor)->ReleaseIPDLReference();
  return true;
}


typedef map<uint64_t,CompositorParent*> CompositorMap;
static CompositorMap* sCompositorMap;

void CompositorParent::CreateCompositorMap()
{
  if (sCompositorMap == nullptr) {
    sCompositorMap = new CompositorMap;
  }
}

void CompositorParent::DestroyCompositorMap()
{
  if (sCompositorMap != nullptr) {
    NS_ASSERTION(sCompositorMap->empty(),
                 "The Compositor map should be empty when destroyed>");
    delete sCompositorMap;
    sCompositorMap = nullptr;
  }
}

CompositorParent* CompositorParent::GetCompositor(uint64_t id)
{
  CompositorMap::iterator it = sCompositorMap->find(id);
  return it != sCompositorMap->end() ? it->second : nullptr;
}

void CompositorParent::AddCompositor(CompositorParent* compositor, uint64_t* outID)
{
  static uint64_t sNextID = 1;

  ++sNextID;
  (*sCompositorMap)[sNextID] = compositor;
  *outID = sNextID;
}

CompositorParent* CompositorParent::RemoveCompositor(uint64_t id)
{
  CompositorMap::iterator it = sCompositorMap->find(id);
  if (it == sCompositorMap->end()) {
    return nullptr;
  }
  CompositorParent *retval = it->second;
  sCompositorMap->erase(it);
  return retval;
}

bool
CompositorParent::RecvNotifyChildCreated(const uint64_t& child)
{
  NotifyChildCreated(child);
  return true;
}

void
CompositorParent::NotifyChildCreated(uint64_t aChild)
{
  sIndirectLayerTrees[aChild].mParent = this;
  sIndirectLayerTrees[aChild].mLayerManager = mLayerManager;
}

/*static*/ uint64_t
CompositorParent::AllocateLayerTreeId()
{
  MOZ_ASSERT(CompositorLoop());
  MOZ_ASSERT(NS_IsMainThread());
  static uint64_t ids = 0;
  return ++ids;
}

static void
EraseLayerState(uint64_t aId)
{
  sIndirectLayerTrees.erase(aId);
}

/*static*/ void
CompositorParent::DeallocateLayerTreeId(uint64_t aId)
{
  MOZ_ASSERT(NS_IsMainThread());
  // Here main thread notifies compositor to remove an element from
  // sIndirectLayerTrees. This removed element might be queried soon.
  // Checking the elements of sIndirectLayerTrees exist or not before using.
  CompositorLoop()->PostTask(FROM_HERE,
                             NewRunnableFunction(&EraseLayerState, aId));
}

static void
UpdateControllerForLayersId(uint64_t aLayersId,
                            GeckoContentController* aController)
{
  // Adopt ref given to us by SetControllerForLayerTree()
  sIndirectLayerTrees[aLayersId].mController =
    already_AddRefed<GeckoContentController>(aController);
}

ScopedLayerTreeRegistration::ScopedLayerTreeRegistration(uint64_t aLayersId,
                                                         Layer* aRoot,
                                                         GeckoContentController* aController)
    : mLayersId(aLayersId)
{
  sIndirectLayerTrees[aLayersId].mRoot = aRoot;
  sIndirectLayerTrees[aLayersId].mController = aController;
}

ScopedLayerTreeRegistration::~ScopedLayerTreeRegistration()
{
  sIndirectLayerTrees.erase(mLayersId);
}

/*static*/ void
CompositorParent::SetControllerForLayerTree(uint64_t aLayersId,
                                            GeckoContentController* aController)
{
  // This ref is adopted by UpdateControllerForLayersId().
  aController->AddRef();
  CompositorLoop()->PostTask(FROM_HERE,
                             NewRunnableFunction(&UpdateControllerForLayersId,
                                                 aLayersId,
                                                 aController));
}

/*static*/ APZCTreeManager*
CompositorParent::GetAPZCTreeManager(uint64_t aLayersId)
{
  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(aLayersId);
  if (state && state->mParent) {
    return state->mParent->mApzcTreeManager;
  }
  return nullptr;
}

float
CompositorParent::ComputeRenderIntegrity()
{
  if (mLayerManager) {
    return mLayerManager->ComputeRenderIntegrity();
  }

  return 1.0f;
}


/**
 * This class handles layer updates pushed directly from child
 * processes to the compositor thread.  It's associated with a
 * CompositorParent on the compositor thread.  While it uses the
 * PCompositor protocol to manage these updates, it doesn't actually
 * drive compositing itself.  For that it hands off work to the
 * CompositorParent it's associated with.
 */
class CrossProcessCompositorParent MOZ_FINAL : public PCompositorParent,
                                               public ShadowLayersManager
{
  friend class CompositorParent;

  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CrossProcessCompositorParent)
public:
  CrossProcessCompositorParent(Transport* aTransport, ProcessId aOtherProcess)
    : mTransport(aTransport)
    , mChildProcessId(aOtherProcess)
  {}

  // IToplevelProtocol::CloneToplevel()
  virtual IToplevelProtocol*
  CloneToplevel(const InfallibleTArray<mozilla::ipc::ProtocolFdMapping>& aFds,
                base::ProcessHandle aPeerProcess,
                mozilla::ipc::ProtocolCloneContext* aCtx) MOZ_OVERRIDE;

  virtual void ActorDestroy(ActorDestroyReason aWhy) MOZ_OVERRIDE;

  // FIXME/bug 774388: work out what shutdown protocol we need.
  virtual bool RecvRequestOverfill() MOZ_OVERRIDE { return true; }
  virtual bool RecvWillStop() MOZ_OVERRIDE { return true; }
  virtual bool RecvStop() MOZ_OVERRIDE { return true; }
  virtual bool RecvPause() MOZ_OVERRIDE { return true; }
  virtual bool RecvResume() MOZ_OVERRIDE { return true; }
  virtual bool RecvNotifyChildCreated(const uint64_t& child) MOZ_OVERRIDE;
  virtual bool RecvMakeSnapshot(const SurfaceDescriptor& aInSnapshot,
                                SurfaceDescriptor* aOutSnapshot)
  { return true; }
  virtual bool RecvFlushRendering() MOZ_OVERRIDE { return true; }
  virtual bool RecvNotifyRegionInvalidated(const nsIntRegion& aRegion) { return true; }
  virtual bool RecvStartFrameTimeRecording(const int32_t& aBufferSize, uint32_t* aOutStartIndex) MOZ_OVERRIDE { return true; }
  virtual bool RecvStopFrameTimeRecording(const uint32_t& aStartIndex, InfallibleTArray<float>* intervals) MOZ_OVERRIDE  { return true; }

  virtual PLayerTransactionParent*
    AllocPLayerTransactionParent(const nsTArray<LayersBackend>& aBackendHints,
                                 const uint64_t& aId,
                                 TextureFactoryIdentifier* aTextureFactoryIdentifier,
                                 bool *aSuccess) MOZ_OVERRIDE;

  virtual bool DeallocPLayerTransactionParent(PLayerTransactionParent* aLayers) MOZ_OVERRIDE;

  virtual void ShadowLayersUpdated(LayerTransactionParent* aLayerTree,
                                   const TargetConfig& aTargetConfig,
                                   bool aIsFirstPaint,
                                   bool aScheduleComposite,
                                   uint32_t aPaintSequenceNumber) MOZ_OVERRIDE;
  virtual void ForceComposite(LayerTransactionParent* aLayerTree) MOZ_OVERRIDE;
  virtual bool SetTestSampleTime(LayerTransactionParent* aLayerTree,
                                 const TimeStamp& aTime) MOZ_OVERRIDE;
  virtual void LeaveTestMode(LayerTransactionParent* aLayerTree) MOZ_OVERRIDE;
  virtual void GetAPZTestData(const LayerTransactionParent* aLayerTree,
                              APZTestData* aOutData) MOZ_OVERRIDE;

  virtual AsyncCompositionManager* GetCompositionManager(LayerTransactionParent* aParent) MOZ_OVERRIDE;

private:
  // Private destructor, to discourage deletion outside of Release():
  virtual ~CrossProcessCompositorParent();

  void DeferredDestroy();

  // There can be many CPCPs, and IPDL-generated code doesn't hold a
  // reference to top-level actors.  So we hold a reference to
  // ourself.  This is released (deferred) in ActorDestroy().
  nsRefPtr<CrossProcessCompositorParent> mSelfRef;
  Transport* mTransport;
  // Child side's process Id.
  base::ProcessId mChildProcessId;
};

static void
OpenCompositor(CrossProcessCompositorParent* aCompositor,
               Transport* aTransport, ProcessHandle aHandle,
               MessageLoop* aIOLoop)
{
  DebugOnly<bool> ok = aCompositor->Open(aTransport, aHandle, aIOLoop);
  MOZ_ASSERT(ok);
}

/*static*/ PCompositorParent*
CompositorParent::Create(Transport* aTransport, ProcessId aOtherProcess)
{
  nsRefPtr<CrossProcessCompositorParent> cpcp =
    new CrossProcessCompositorParent(aTransport, aOtherProcess);
  ProcessHandle handle;
  if (!base::OpenProcessHandle(aOtherProcess, &handle)) {
    // XXX need to kill |aOtherProcess|, it's boned
    return nullptr;
  }

  cpcp->mSelfRef = cpcp;
  CompositorLoop()->PostTask(
    FROM_HERE,
    NewRunnableFunction(OpenCompositor, cpcp.get(),
                        aTransport, handle, XRE_GetIOMessageLoop()));
  // The return value is just compared to null for success checking,
  // we're not sharing a ref.
  return cpcp.get();
}

IToplevelProtocol*
CompositorParent::CloneToplevel(const InfallibleTArray<mozilla::ipc::ProtocolFdMapping>& aFds,
                                base::ProcessHandle aPeerProcess,
                                mozilla::ipc::ProtocolCloneContext* aCtx)
{
  for (unsigned int i = 0; i < aFds.Length(); i++) {
    if (aFds[i].protocolId() == (unsigned)GetProtocolId()) {
      Transport* transport = OpenDescriptor(aFds[i].fd(),
                                            Transport::MODE_SERVER);
      PCompositorParent* compositor = Create(transport, base::GetProcId(aPeerProcess));
      compositor->CloneManagees(this, aCtx);
      compositor->IToplevelProtocol::SetTransport(transport);
      return compositor;
    }
  }
  return nullptr;
}

static void
UpdateIndirectTree(uint64_t aId, Layer* aRoot, const TargetConfig& aTargetConfig)
{
  sIndirectLayerTrees[aId].mRoot = aRoot;
  sIndirectLayerTrees[aId].mTargetConfig = aTargetConfig;
}

/* static */ CompositorParent::LayerTreeState*
CompositorParent::GetIndirectShadowTree(uint64_t aId)
{
  LayerTreeMap::iterator cit = sIndirectLayerTrees.find(aId);
  if (sIndirectLayerTrees.end() == cit) {
    return nullptr;
  }
  return &cit->second;
}

static void
RemoveIndirectTree(uint64_t aId)
{
  sIndirectLayerTrees.erase(aId);
}

void
CrossProcessCompositorParent::ActorDestroy(ActorDestroyReason aWhy)
{
  fprintf(stderr, " --- CrossProcessCompositorParent ActorDestroy\n");
  MessageLoop::current()->PostTask(
    FROM_HERE,
    NewRunnableMethod(this, &CrossProcessCompositorParent::DeferredDestroy));
}

PLayerTransactionParent*
CrossProcessCompositorParent::AllocPLayerTransactionParent(const nsTArray<LayersBackend>&,
                                                           const uint64_t& aId,
                                                           TextureFactoryIdentifier* aTextureFactoryIdentifier,
                                                           bool *aSuccess)
{
  MOZ_ASSERT(aId != 0);

  CompositorParent::LayerTreeState* state = nullptr;
  LayerTreeMap::iterator itr = sIndirectLayerTrees.find(aId);
  if (sIndirectLayerTrees.end() != itr) {
    state = &itr->second;
  }

  if (state && state->mLayerManager) {
    state->mCrossProcessParent = this;
    LayerManagerComposite* lm = state->mLayerManager;
    *aTextureFactoryIdentifier = lm->GetCompositor()->GetTextureFactoryIdentifier();
    *aSuccess = true;
    LayerTransactionParent* p = new LayerTransactionParent(lm, this, aId, mChildProcessId);
    p->AddIPDLReference();
    return p;
  }

  NS_WARNING("Created child without a matching parent?");
  // XXX: should be false, but that causes us to fail some tests on Mac w/ OMTC.
  // Bug 900745. change *aSuccess to false to see test failures.
  *aSuccess = true;
  LayerTransactionParent* p = new LayerTransactionParent(nullptr, this, aId, mChildProcessId);
  p->AddIPDLReference();
  return p;
}

bool
CrossProcessCompositorParent::DeallocPLayerTransactionParent(PLayerTransactionParent* aLayers)
{
  LayerTransactionParent* slp = static_cast<LayerTransactionParent*>(aLayers);
  RemoveIndirectTree(slp->GetId());
  static_cast<LayerTransactionParent*>(aLayers)->ReleaseIPDLReference();
  return true;
}

bool
CrossProcessCompositorParent::RecvNotifyChildCreated(const uint64_t& child)
{
  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(child);
  if (!state) {
    return false;
  }

  MOZ_ASSERT(state->mParent);
  state->mParent->NotifyChildCreated(child);
  return true;
}

void
CrossProcessCompositorParent::ShadowLayersUpdated(
  LayerTransactionParent* aLayerTree,
  const TargetConfig& aTargetConfig,
  bool aIsFirstPaint,
  bool aScheduleComposite,
  uint32_t aPaintSequenceNumber)
{
  uint64_t id = aLayerTree->GetId();

  MOZ_ASSERT(id != 0);

  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
  if (!state) {
    return;
  }
  MOZ_ASSERT(state->mParent);
  state->mParent->ScheduleRotationOnCompositorThread(aTargetConfig, aIsFirstPaint);

  Layer* shadowRoot = aLayerTree->GetRoot();
  if (shadowRoot) {
    SetShadowProperties(shadowRoot);
  }
  UpdateIndirectTree(id, shadowRoot, aTargetConfig);

  state->mParent->NotifyShadowTreeTransaction(id, aIsFirstPaint, aScheduleComposite,
      aPaintSequenceNumber);
}

void
CrossProcessCompositorParent::ForceComposite(LayerTransactionParent* aLayerTree)
{
  uint64_t id = aLayerTree->GetId();
  MOZ_ASSERT(id != 0);
  sIndirectLayerTrees[id].mParent->ForceComposite(aLayerTree);
}

bool
CrossProcessCompositorParent::SetTestSampleTime(
  LayerTransactionParent* aLayerTree, const TimeStamp& aTime)
{
  uint64_t id = aLayerTree->GetId();
  MOZ_ASSERT(id != 0);
  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
  if (!state) {
    return false;
  }

  MOZ_ASSERT(state->mParent);
  return state->mParent->SetTestSampleTime(aLayerTree, aTime);
}

void
CrossProcessCompositorParent::LeaveTestMode(LayerTransactionParent* aLayerTree)
{
  uint64_t id = aLayerTree->GetId();
  MOZ_ASSERT(id != 0);
  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
  if (!state) {
    return;
  }

  MOZ_ASSERT(state->mParent);
  state->mParent->LeaveTestMode(aLayerTree);
}

void
CrossProcessCompositorParent::GetAPZTestData(const LayerTransactionParent* aLayerTree,
                                             APZTestData* aOutData)
{
  uint64_t id = aLayerTree->GetId();
  MOZ_ASSERT(id != 0);
  *aOutData = sIndirectLayerTrees[id].mApzTestData;
}


AsyncCompositionManager*
CrossProcessCompositorParent::GetCompositionManager(LayerTransactionParent* aLayerTree)
{
  uint64_t id = aLayerTree->GetId();
  const CompositorParent::LayerTreeState* state = CompositorParent::GetIndirectShadowTree(id);
  if (!state) {
    return nullptr;
  }

  MOZ_ASSERT(state->mParent);
  return state->mParent->GetCompositionManager(aLayerTree);
}

void
CrossProcessCompositorParent::DeferredDestroy()
{

  fprintf(stderr, " --- CrossProcessCompositorParent DeferredDestroy\n");
  CrossProcessCompositorParent* self;
  mSelfRef.forget(&self);

  nsCOMPtr<nsIRunnable> runnable =
    NS_NewNonOwningRunnableMethod(self, &CrossProcessCompositorParent::Release);
  MOZ_ALWAYS_TRUE(NS_SUCCEEDED(NS_DispatchToMainThread(runnable)));
}

CrossProcessCompositorParent::~CrossProcessCompositorParent()
{
  fprintf(stderr, " --- CrossProcessCompositorParent destructor\n");

  XRE_GetIOMessageLoop()->PostTask(FROM_HERE,
                                   new DeleteTask<Transport>(mTransport));
}

IToplevelProtocol*
CrossProcessCompositorParent::CloneToplevel(const InfallibleTArray<mozilla::ipc::ProtocolFdMapping>& aFds,
                                            base::ProcessHandle aPeerProcess,
                                            mozilla::ipc::ProtocolCloneContext* aCtx)
{
  for (unsigned int i = 0; i < aFds.Length(); i++) {
    if (aFds[i].protocolId() == (unsigned)GetProtocolId()) {
      Transport* transport = OpenDescriptor(aFds[i].fd(),
                                            Transport::MODE_SERVER);
      PCompositorParent* compositor =
        CompositorParent::Create(transport, base::GetProcId(aPeerProcess));
      compositor->CloneManagees(this, aCtx);
      compositor->IToplevelProtocol::SetTransport(transport);
      return compositor;
    }
  }
  return nullptr;
}

} // namespace layers
} // namespace mozilla