ShadowLayers.h
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=8 et :
*/
/* 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/. */
#ifndef mozilla_layers_ShadowLayers_h
#define mozilla_layers_ShadowLayers_h 1
#include <stddef.h> // for size_t
#include <stdint.h> // for uint64_t
#include "gfxTypes.h"
#include "gfxPoint.h" // for gfxIntSize
#include "mozilla/Attributes.h" // for MOZ_OVERRIDE
#include "mozilla/WidgetUtils.h" // for ScreenRotation
#include "mozilla/dom/ScreenOrientation.h" // for ScreenOrientation
#include "mozilla/ipc/SharedMemory.h" // for SharedMemory, etc
#include "mozilla/layers/CompositableForwarder.h"
#include "mozilla/layers/CompositorTypes.h" // for OpenMode, etc
#include "nsCOMPtr.h" // for already_AddRefed
#include "nsRegion.h" // for nsIntRegion
#include "nsTArrayForwardDeclare.h" // for InfallibleTArray
struct nsIntPoint;
struct nsIntRect;
class gfxASurface;
namespace mozilla {
namespace layers {
class BasicTiledLayerBuffer;
class CanvasClient;
class CanvasLayerComposite;
class CanvasSurface;
class ColorLayerComposite;
class CompositableChild;
class ContainerLayerComposite;
class ContentClient;
class ContentClientRemote;
class EditReply;
class ImageClient;
class ImageLayerComposite;
class Layer;
class OptionalThebesBuffer;
class PLayerChild;
class PLayerTransactionChild;
class PLayerTransactionParent;
class LayerTransactionChild;
class RefLayerComposite;
class ShadowableLayer;
class Shmem;
class ShmemTextureClient;
class SurfaceDescriptor;
class TextureClient;
class ThebesLayerComposite;
class ThebesBuffer;
class ThebesBufferData;
class TiledLayerComposer;
class Transaction;
/**
* We want to share layer trees across thread contexts and address
* spaces for several reasons; chief among them
*
* - a parent process can paint a child process's layer tree while
* the child process is blocked, say on content script. This is
* important on mobile devices where UI responsiveness is key.
*
* - a dedicated "compositor" process can asynchronously (wrt the
* browser process) composite and animate layer trees, allowing a
* form of pipeline parallelism between compositor/browser/content
*
* - a dedicated "compositor" process can take all responsibility for
* accessing the GPU, which is desirable on systems with
* buggy/leaky drivers because the compositor process can die while
* browser and content live on (and failover mechanisms can be
* installed to quickly bring up a replacement compositor)
*
* The Layers model has a crisply defined API, which makes it easy to
* safely "share" layer trees. The ShadowLayers API extends Layers to
* allow a remote, parent process to access a child process's layer
* tree.
*
* ShadowLayerForwarder publishes a child context's layer tree to a
* parent context. This comprises recording layer-tree modifications
* into atomic transactions and pushing them over IPC.
*
* LayerManagerComposite grafts layer subtrees published by child-context
* ShadowLayerForwarder(s) into a parent-context layer tree.
*
* (Advanced note: because our process tree may have a height >2, a
* non-leaf subprocess may both receive updates from child processes
* and publish them to parent processes. Put another way,
* LayerManagers may be both LayerManagerComposites and
* ShadowLayerForwarders.)
*
* There are only shadow types for layers that have different shadow
* vs. not-shadow behavior. ColorLayers and ContainerLayers behave
* the same way in both regimes (so far).
*
*
* The mecanism to shadow the layer tree on the compositor through IPC works as
* follows:
* The layer tree is managed on the content thread, and shadowed in the compositor
* thread. The shadow layer tree is only kept in sync with whatever happens in
* the content thread. To do this we use IPDL protocols. IPDL is a domain
* specific language that describes how two processes or thread should
* communicate. C++ code is generated from .ipdl files to implement the message
* passing, synchronization and serialization logic. To use the generated code
* we implement classes that inherit the generated IPDL actor. the ipdl actors
* of a protocol PX are PXChild or PXParent (the generated class), and we
* conventionally implement XChild and XParent. The Parent side of the protocol
* is the one that lives on the compositor thread. Think of IPDL actors as
* endpoints of communication. they are useful to send messages and also to
* dispatch the message to the right actor on the other side. One nice property
* of an IPDL actor is that when an actor, say PXChild is sent in a message, the
* PXParent comes out in the other side. we use this property a lot to dispatch
* messages to the right layers and compositable, each of which have their own
* ipdl actor on both side.
*
* Most of the synchronization logic happens in layer transactions and
* compositable transactions.
* A transaction is a set of changes to the layers and/or the compositables
* that are sent and applied together to the compositor thread to keep the
* LayerComposite in a coherent state.
* Layer transactions maintain the shape of the shadow layer tree, and
* synchronize the texture data held by compositables. Layer transactions
* are always between the content thread and the compositor thread.
* Compositable transactions are subset of a layer transaction with which only
* compositables and textures can be manipulated, and does not always originate
* from the content thread. (See CompositableForwarder.h and ImageBridgeChild.h)
*/
class ShadowLayerForwarder : public CompositableForwarder
{
friend class AutoOpenSurface;
friend class DeprecatedTextureClientShmem;
friend class ContentClientIncremental;
friend class ClientLayerManager;
public:
virtual ~ShadowLayerForwarder();
/**
* Setup the IPDL actor for aCompositable to be part of layers
* transactions.
*/
void Connect(CompositableClient* aCompositable);
virtual void CreatedSingleBuffer(CompositableClient* aCompositable,
const SurfaceDescriptor& aDescriptor,
const TextureInfo& aTextureInfo,
const SurfaceDescriptor* aDescriptorOnWhite = nullptr) MOZ_OVERRIDE;
virtual void CreatedIncrementalBuffer(CompositableClient* aCompositable,
const TextureInfo& aTextureInfo,
const nsIntRect& aBufferRect) MOZ_OVERRIDE;
virtual void CreatedDoubleBuffer(CompositableClient* aCompositable,
const SurfaceDescriptor& aFrontDescriptor,
const SurfaceDescriptor& aBackDescriptor,
const TextureInfo& aTextureInfo,
const SurfaceDescriptor* aFrontDescriptorOnWhite = nullptr,
const SurfaceDescriptor* aBackDescriptorOnWhite = nullptr) MOZ_OVERRIDE;
virtual void DestroyThebesBuffer(CompositableClient* aCompositable) MOZ_OVERRIDE;
/**
* Adds an edit in the layers transaction in order to attach
* the corresponding compositable and layer on the compositor side.
* Connect must have been called on aCompositable beforehand.
*/
void Attach(CompositableClient* aCompositable,
ShadowableLayer* aLayer);
/**
* Adds an edit in the transaction in order to attach a Compositable that
* is not managed by this ShadowLayerForwarder (for example, by ImageBridge
* in the case of async-video).
* Since the compositable is not managed by this forwarder, we can't use
* the compositable or it's IPDL actor here, so we use an ID instead, that
* is matched on the compositor side.
*/
void AttachAsyncCompositable(uint64_t aCompositableID,
ShadowableLayer* aLayer);
/**
* Begin recording a transaction to be forwarded atomically to a
* LayerManagerComposite.
*/
void BeginTransaction(const nsIntRect& aTargetBounds,
ScreenRotation aRotation,
const nsIntRect& aClientBounds,
mozilla::dom::ScreenOrientation aOrientation);
/**
* The following methods may only be called after BeginTransaction()
* but before EndTransaction(). They mirror the LayerManager
* interface in Layers.h.
*/
/**
* Notify the shadow manager that a new, "real" layer has been
* created, and a corresponding shadow layer should be created in
* the compositing process.
*/
void CreatedThebesLayer(ShadowableLayer* aThebes);
void CreatedContainerLayer(ShadowableLayer* aContainer);
void CreatedImageLayer(ShadowableLayer* aImage);
void CreatedColorLayer(ShadowableLayer* aColor);
void CreatedCanvasLayer(ShadowableLayer* aCanvas);
void CreatedRefLayer(ShadowableLayer* aRef);
/**
* The specified layer is destroying its buffers.
* |aBackBufferToDestroy| is deallocated when this transaction is
* posted to the parent. During the parent-side transaction, the
* shadow is told to destroy its front buffer. This can happen when
* a new front/back buffer pair have been created because of a layer
* resize, e.g.
*/
virtual void DestroyedThebesBuffer(const SurfaceDescriptor& aBackBufferToDestroy) MOZ_OVERRIDE;
/**
* At least one attribute of |aMutant| has changed, and |aMutant|
* needs to sync to its shadow layer. This initial implementation
* forwards all attributes when any is mutated.
*/
void Mutated(ShadowableLayer* aMutant);
void SetRoot(ShadowableLayer* aRoot);
/**
* Insert |aChild| after |aAfter| in |aContainer|. |aAfter| can be
* nullptr to indicated that |aChild| should be appended to the end of
* |aContainer|'s child list.
*/
void InsertAfter(ShadowableLayer* aContainer,
ShadowableLayer* aChild,
ShadowableLayer* aAfter = nullptr);
void RemoveChild(ShadowableLayer* aContainer,
ShadowableLayer* aChild);
void RepositionChild(ShadowableLayer* aContainer,
ShadowableLayer* aChild,
ShadowableLayer* aAfter = nullptr);
/**
* Set aMaskLayer as the mask on aLayer.
* Note that only image layers are properly supported
* LayerTransactionParent::UpdateMask and accompanying ipdl
* will need changing to update properties for other kinds
* of mask layer.
*/
void SetMask(ShadowableLayer* aLayer,
ShadowableLayer* aMaskLayer);
/**
* Notify the compositor that a tiled layer buffer has changed
* that needs to be synced to the shadow retained copy. The tiled
* layer buffer will operate directly on the shadow retained buffer
* and is free to choose it's own internal representation (double buffering,
* copy on write, tiling).
*/
virtual void PaintedTiledLayerBuffer(CompositableClient* aCompositable,
const SurfaceDescriptorTiles& aTileLayerDescriptor) MOZ_OVERRIDE;
/**
* Notify the compositor that a compositable will be updated asynchronously
* through ImageBridge, using an ID to connect the protocols on the
* compositor side.
*/
void AttachAsyncCompositable(PLayerTransactionChild* aLayer, uint64_t aID);
/**
* Communicate to the compositor that the texture identified by aLayer
* and aIdentifier has been updated to aImage.
*/
virtual void UpdateTexture(CompositableClient* aCompositable,
TextureIdentifier aTextureId,
SurfaceDescriptor* aDescriptor) MOZ_OVERRIDE;
/**
* Same as above, but performs an asynchronous layer transaction
*/
virtual void UpdateTextureNoSwap(CompositableClient* aCompositable,
TextureIdentifier aTextureId,
SurfaceDescriptor* aDescriptor) MOZ_OVERRIDE;
/**
* Communicate to the compositor that aRegion in the texture identified by aLayer
* and aIdentifier has been updated to aThebesBuffer.
*/
virtual void UpdateTextureRegion(CompositableClient* aCompositable,
const ThebesBufferData& aThebesBufferData,
const nsIntRegion& aUpdatedRegion) MOZ_OVERRIDE;
virtual void UpdateTextureIncremental(CompositableClient* aCompositable,
TextureIdentifier aTextureId,
SurfaceDescriptor& aDescriptor,
const nsIntRegion& aUpdatedRegion,
const nsIntRect& aBufferRect,
const nsIntPoint& aBufferRotation) MOZ_OVERRIDE;
/**
* Communicate the picture rect of an image to the compositor
*/
void UpdatePictureRect(CompositableClient* aCompositable,
const nsIntRect& aRect);
/**
* See CompositableForwarder::AddTexture
*/
virtual bool AddTexture(CompositableClient* aCompositable,
TextureClient* aClient) MOZ_OVERRIDE;
/**
* See CompositableForwarder::RemoveTexture
*/
virtual void RemoveTexture(CompositableClient* aCompositable,
uint64_t aTextureID,
TextureFlags aFlags) MOZ_OVERRIDE;
/**
* See CompositableForwarder::UpdatedTexture
*/
virtual void UpdatedTexture(CompositableClient* aCompositable,
TextureClient* aTexture,
nsIntRegion* aRegion) MOZ_OVERRIDE;
/**
* See CompositableForwarder::UseTexture
*/
virtual void UseTexture(CompositableClient* aCompositable,
TextureClient* aClient) MOZ_OVERRIDE;
/**
* End the current transaction and forward it to LayerManagerComposite.
* |aReplies| are directions from the LayerManagerComposite to the
* caller of EndTransaction().
*/
bool EndTransaction(InfallibleTArray<EditReply>* aReplies, bool* aSent);
/**
* Set an actor through which layer updates will be pushed.
*/
void SetShadowManager(PLayerTransactionChild* aShadowManager);
/**
* True if this is forwarding to a LayerManagerComposite.
*/
bool HasShadowManager() const { return !!mShadowManager; }
LayerTransactionChild* GetShadowManager() const { return mShadowManager.get(); }
virtual void WindowOverlayChanged() { mWindowOverlayChanged = true; }
/**
* The following Alloc/Open/Destroy interfaces abstract over the
* details of working with surfaces that are shared across
* processes. They provide the glue between C++ Layers and the
* LayerComposite IPC system.
*
* The basic lifecycle is
*
* - a Layer needs a buffer. Its ShadowableLayer subclass calls
* AllocBuffer(), then calls one of the Created*Buffer() methods
* above to transfer the (temporary) front buffer to its
* LayerComposite in the other process. The Layer needs a
* gfxASurface to paint, so the ShadowableLayer uses
* OpenDescriptor(backBuffer) to get that surface, and hands it
* out to the Layer.
*
* - a Layer has painted new pixels. Its ShadowableLayer calls one
* of the Painted*Buffer() methods above with the back buffer
* descriptor. This notification is forwarded to the LayerComposite,
* which uses OpenDescriptor() to access the newly-painted pixels.
* The LayerComposite then updates its front buffer in a Layer- and
* platform-dependent way, and sends a surface descriptor back to
* the ShadowableLayer that becomes its new back back buffer.
*
* - a Layer wants to destroy its buffers. Its ShadowableLayer
* calls Destroyed*Buffer(), which gives up control of the back
* buffer descriptor. The actual back buffer surface is then
* destroyed using DestroySharedSurface() just before notifying
* the parent process. When the parent process is notified, the
* LayerComposite also calls DestroySharedSurface() on its front
* buffer, and the double-buffer pair is gone.
*/
// ISurfaceAllocator
virtual bool AllocUnsafeShmem(size_t aSize,
mozilla::ipc::SharedMemory::SharedMemoryType aType,
mozilla::ipc::Shmem* aShmem) MOZ_OVERRIDE;
virtual bool AllocShmem(size_t aSize,
mozilla::ipc::SharedMemory::SharedMemoryType aType,
mozilla::ipc::Shmem* aShmem) MOZ_OVERRIDE;
virtual void DeallocShmem(mozilla::ipc::Shmem& aShmem) MOZ_OVERRIDE;
virtual bool IPCOpen() const MOZ_OVERRIDE;
/**
* Construct a shadow of |aLayer| on the "other side", at the
* LayerManagerComposite.
*/
PLayerChild* ConstructShadowFor(ShadowableLayer* aLayer);
/**
* Flag the next paint as the first for a document.
*/
void SetIsFirstPaint() { mIsFirstPaint = true; }
static void PlatformSyncBeforeUpdate();
static already_AddRefed<gfxASurface>
OpenDescriptor(OpenMode aMode, const SurfaceDescriptor& aSurface);
protected:
ShadowLayerForwarder();
#ifdef DEBUG
void CheckSurfaceDescriptor(const SurfaceDescriptor* aDescriptor) const;
#else
void CheckSurfaceDescriptor(const SurfaceDescriptor* aDescriptor) const {}
#endif
RefPtr<LayerTransactionChild> mShadowManager;
#ifdef MOZ_HAVE_SURFACEDESCRIPTORGRALLOC
// from ISurfaceAllocator
virtual PGrallocBufferChild* AllocGrallocBuffer(const gfxIntSize& aSize,
uint32_t aFormat,
uint32_t aUsage,
MaybeMagicGrallocBufferHandle* aHandle) MOZ_OVERRIDE;
#endif
private:
/**
* Try to query the content type efficiently, but at worst map the
* surface and return it in *aSurface.
*/
static gfxContentType
GetDescriptorSurfaceContentType(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxASurface** aSurface);
/**
* It can be expensive to open a descriptor just to query its
* content type. If the platform impl can do this cheaply, it will
* set *aContent and return true.
*/
static bool
PlatformGetDescriptorSurfaceContentType(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxContentType* aContent,
gfxASurface** aSurface);
// (Same as above, but for surface size.)
static gfxIntSize
GetDescriptorSurfaceSize(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxASurface** aSurface);
static bool
PlatformGetDescriptorSurfaceSize(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxIntSize* aSize,
gfxASurface** aSurface);
// And again, for the image format.
// This function will return gfxImageFormatUnknown only if |aDescriptor|
// describes a non-ImageSurface.
static gfxImageFormat
GetDescriptorSurfaceImageFormat(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxASurface** aSurface);
static bool
PlatformGetDescriptorSurfaceImageFormat(const SurfaceDescriptor& aDescriptor,
OpenMode aMode,
gfxImageFormat* aContent,
gfxASurface** aSurface);
static already_AddRefed<gfxASurface>
PlatformOpenDescriptor(OpenMode aMode, const SurfaceDescriptor& aDescriptor);
/**
* Make this descriptor unusable for gfxASurface clients. A
* private interface with AutoOpenSurface.
*/
static void
CloseDescriptor(const SurfaceDescriptor& aDescriptor);
static bool
PlatformCloseDescriptor(const SurfaceDescriptor& aDescriptor);
bool PlatformDestroySharedSurface(SurfaceDescriptor* aSurface);
Transaction* mTxn;
DiagnosticTypes mDiagnosticTypes;
bool mIsFirstPaint;
bool mWindowOverlayChanged;
};
class CompositableClient;
/**
* A ShadowableLayer is a Layer can be shared with a parent context
* through a ShadowLayerForwarder. A ShadowableLayer maps to a
* Shadow*Layer in a parent context.
*
* Note that ShadowLayers can themselves be ShadowableLayers.
*/
class ShadowableLayer
{
public:
virtual ~ShadowableLayer() {}
virtual Layer* AsLayer() = 0;
/**
* True if this layer has a shadow in a parent process.
*/
bool HasShadow() { return !!mShadow; }
/**
* Return the IPC handle to a Shadow*Layer referring to this if one
* exists, nullptr if not.
*/
PLayerChild* GetShadow() { return mShadow; }
virtual CompositableClient* GetCompositableClient() { return nullptr; }
protected:
ShadowableLayer() : mShadow(nullptr) {}
PLayerChild* mShadow;
};
} // namespace layers
} // namespace mozilla
#endif // ifndef mozilla_layers_ShadowLayers_h
