gecko-dev/gfx/layers/ipc/CompositorChild.cpp

/* -*- 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 "CompositorChild.h"
#include <stddef.h>                     // for size_t
#include "ClientLayerManager.h"         // for ClientLayerManager
#include "base/message_loop.h"          // for MessageLoop
#include "base/process_util.h"          // for OpenProcessHandle
#include "base/task.h"                  // for NewRunnableMethod, etc
#include "base/tracked.h"               // for FROM_HERE
#include "mozilla/layers/LayerTransactionChild.h"
#include "mozilla/layers/PLayerTransactionChild.h"
#include "mozilla/mozalloc.h"           // for operator new, etc
#include "nsDebug.h"                    // for NS_RUNTIMEABORT
#include "nsIObserver.h"                // for nsIObserver
#include "nsISupportsImpl.h"            // for MOZ_COUNT_CTOR, etc
#include "nsTArray.h"                   // for nsTArray, nsTArray_Impl
#include "nsXULAppAPI.h"                // for XRE_GetIOMessageLoop, etc
#include "FrameLayerBuilder.h"

using mozilla::layers::LayerTransactionChild;

namespace mozilla {
namespace layers {

/*static*/ CompositorChild* CompositorChild::sCompositor;

Atomic<int32_t> CompositableForwarder::sSerialCounter(0);

CompositorChild::CompositorChild(ClientLayerManager *aLayerManager)
  : mLayerManager(aLayerManager)
{
  MOZ_COUNT_CTOR(CompositorChild);
}

CompositorChild::~CompositorChild()
{
  MOZ_COUNT_DTOR(CompositorChild);
}

void
CompositorChild::Destroy()
{
  mLayerManager->Destroy();
  mLayerManager = nullptr;
  while (size_t len = ManagedPLayerTransactionChild().Length()) {
    LayerTransactionChild* layers =
      static_cast<LayerTransactionChild*>(ManagedPLayerTransactionChild()[len - 1]);
    layers->Destroy();
  }
  SendStop();
}

bool
CompositorChild::LookupCompositorFrameMetrics(const FrameMetrics::ViewID aId,
                                              FrameMetrics& aFrame)
{
  SharedFrameMetricsData* data = mFrameMetricsTable.Get(aId);
  if (data) {
    data->CopyFrameMetrics(&aFrame);
    return true;
  }
  return false;
}

/*static*/ PCompositorChild*
CompositorChild::Create(Transport* aTransport, ProcessId aOtherProcess)
{
  // There's only one compositor per child process.
  MOZ_ASSERT(!sCompositor);

  nsRefPtr<CompositorChild> child(new CompositorChild(nullptr));
  ProcessHandle handle;
  if (!base::OpenProcessHandle(aOtherProcess, &handle)) {
    // We can't go on without a compositor.
    NS_RUNTIMEABORT("Couldn't OpenProcessHandle() to parent process.");
    return nullptr;
  }
  if (!child->Open(aTransport, handle, XRE_GetIOMessageLoop(), ipc::ChildSide)) {
    NS_RUNTIMEABORT("Couldn't Open() Compositor channel.");
    return nullptr;
  }
  // We release this ref in ActorDestroy().
  return sCompositor = child.forget().take();
}

/*static*/ CompositorChild*
CompositorChild::Get()
{
  // This is only expected to be used in child processes.
  MOZ_ASSERT(XRE_GetProcessType() != GeckoProcessType_Default);
  return sCompositor;
}

PLayerTransactionChild*
CompositorChild::AllocPLayerTransactionChild(const nsTArray<LayersBackend>& aBackendHints,
                                             const uint64_t& aId,
                                             TextureFactoryIdentifier*,
                                             bool*)
{
  LayerTransactionChild* c = new LayerTransactionChild();
  c->AddIPDLReference();
  return c;
}

bool
CompositorChild::DeallocPLayerTransactionChild(PLayerTransactionChild* actor)
{
  static_cast<LayerTransactionChild*>(actor)->ReleaseIPDLReference();
  return true;
}

bool
CompositorChild::RecvInvalidateAll()
{
  FrameLayerBuilder::InvalidateAllLayers(mLayerManager);
  return true;
}

void
CompositorChild::ActorDestroy(ActorDestroyReason aWhy)
{
  MOZ_ASSERT(sCompositor == this);

#ifdef MOZ_B2G
  // Due to poor lifetime management of gralloc (and possibly shmems) we will
  // crash at some point in the future when we get destroyed due to abnormal
  // shutdown. Its better just to crash here. On desktop though, we have a chance
  // of recovering.
  if (aWhy == AbnormalShutdown) {
    NS_RUNTIMEABORT("ActorDestroy by IPC channel failure at CompositorChild");
  }
#endif

  sCompositor = nullptr;
  // We don't want to release the ref to sCompositor here, during
  // cleanup, because that will cause it to be deleted while it's
  // still being used.  So defer the deletion to after it's not in
  // use.
  MessageLoop::current()->PostTask(
    FROM_HERE,
    NewRunnableMethod(this, &CompositorChild::Release));
}

bool
CompositorChild::RecvSharedCompositorFrameMetrics(
    const mozilla::ipc::SharedMemoryBasic::Handle& metrics,
    const CrossProcessMutexHandle& handle,
    const uint32_t& aAPZCId)
{
  SharedFrameMetricsData* data = new SharedFrameMetricsData(metrics, handle, aAPZCId);
  mFrameMetricsTable.Put(data->GetViewID(), data);
  return true;
}

bool
CompositorChild::RecvReleaseSharedCompositorFrameMetrics(
    const ViewID& aId,
    const uint32_t& aAPZCId)
{
  SharedFrameMetricsData* data = mFrameMetricsTable.Get(aId);
  // The SharedFrameMetricsData may have been removed previously if
  // a SharedFrameMetricsData with the same ViewID but later APZCId had
  // been store and over wrote it.
  if (data && (data->GetAPZCId() == aAPZCId)) {
    mFrameMetricsTable.Remove(aId);
  }
  return true;
}

CompositorChild::SharedFrameMetricsData::SharedFrameMetricsData(
    const ipc::SharedMemoryBasic::Handle& metrics,
    const CrossProcessMutexHandle& handle,
    const uint32_t& aAPZCId) :
    mBuffer(nullptr),
    mMutex(nullptr),
    mAPZCId(aAPZCId)
{
  mBuffer = new ipc::SharedMemoryBasic(metrics);
  mBuffer->Map(sizeof(FrameMetrics));
  mMutex = new CrossProcessMutex(handle);
  MOZ_COUNT_CTOR(SharedFrameMetricsData);
}

CompositorChild::SharedFrameMetricsData::~SharedFrameMetricsData()
{
  // When the hash table deletes the class, delete
  // the shared memory and mutex.
  delete mMutex;
  delete mBuffer;
  MOZ_COUNT_DTOR(SharedFrameMetricsData);
}

void
CompositorChild::SharedFrameMetricsData::CopyFrameMetrics(FrameMetrics* aFrame)
{
  FrameMetrics* frame = static_cast<FrameMetrics*>(mBuffer->memory());
  MOZ_ASSERT(frame);
  mMutex->Lock();
  *aFrame = *frame;
  mMutex->Unlock();
}

FrameMetrics::ViewID
CompositorChild::SharedFrameMetricsData::GetViewID()
{
  FrameMetrics* frame = static_cast<FrameMetrics*>(mBuffer->memory());
  MOZ_ASSERT(frame);
  // Not locking to read of mScrollId since it should not change after being
  // initially set.
  return frame->GetScrollId();
}

uint32_t
CompositorChild::SharedFrameMetricsData::GetAPZCId()
{
  return mAPZCId;
}

} // namespace layers
} // namespace mozilla