import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

gfx/layers/ipc/ShadowLayers.h

@@ -0,0 +1,465 @@
+/* -*- 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 "mozilla/Attributes.h"         // for override
+#include "mozilla/gfx/Rect.h"
+#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/TextureForwarder.h"
+#include "mozilla/layers/CompositorTypes.h"  // for OpenMode, etc
+#include "mozilla/layers/CompositorBridgeChild.h"
+#include "nsCOMPtr.h"                   // for already_AddRefed
+#include "nsRegion.h"                   // for nsIntRegion
+#include "nsTArrayForwardDeclare.h"     // for InfallibleTArray
+#include "nsIWidget.h"
+#include <vector>
+#include "nsExpirationTracker.h"
+
+namespace mozilla {
+namespace layers {
+
+class ClientLayerManager;
+class CompositorBridgeChild;
+class EditReply;
+class FixedSizeSmallShmemSectionAllocator;
+class ImageContainer;
+class Layer;
+class PLayerChild;
+class PLayerTransactionChild;
+class LayerTransactionChild;
+class ShadowableLayer;
+class SurfaceDescriptor;
+class TextureClient;
+class ThebesBuffer;
+class ThebesBufferData;
+class Transaction;
+
+/**
+ * See ActiveResourceTracker below.
+ */
+class ActiveResource
+{
+public:
+ virtual void NotifyInactive() = 0;
+  nsExpirationState* GetExpirationState() { return &mExpirationState; }
+  bool IsActivityTracked() { return mExpirationState.IsTracked(); }
+private:
+  nsExpirationState mExpirationState;
+};
+
+/**
+ * A convenience class on top of nsExpirationTracker
+ */
+class ActiveResourceTracker : public nsExpirationTracker<ActiveResource, 3>
+{
+public:
+  ActiveResourceTracker(uint32_t aExpirationCycle, const char* aName)
+  : nsExpirationTracker(aExpirationCycle, aName)
+  {}
+
+  virtual void NotifyExpired(ActiveResource* aResource) override
+  {
+    RemoveObject(aResource);
+    aResource->NotifyInactive();
+  }
+};
+
+/**
+ * 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 final : public LayersIPCActor
+                                 , public CompositableForwarder
+                                 , public LegacySurfaceDescriptorAllocator
+{
+  friend class ClientLayerManager;
+
+public:
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ShadowLayerForwarder, override);
+
+  /**
+   * Setup the IPDL actor for aCompositable to be part of layers
+   * transactions.
+   */
+  void Connect(CompositableClient* aCompositable,
+               ImageContainer* aImageContainer) 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 gfx::IntRect& aTargetBounds,
+                        ScreenRotation aRotation,
+                        mozilla::dom::ScreenOrientationInternal 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 CreatedPaintedLayer(ShadowableLayer* aThebes);
+  void CreatedContainerLayer(ShadowableLayer* aContainer);
+  void CreatedImageLayer(ShadowableLayer* aImage);
+  void CreatedColorLayer(ShadowableLayer* aColor);
+  void CreatedCanvasLayer(ShadowableLayer* aCanvas);
+  void CreatedRefLayer(ShadowableLayer* aRef);
+
+  /**
+   * 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);
+
+  /**
+   * See CompositableForwarder::UseTiledLayerBuffer
+   */
+  void UseTiledLayerBuffer(CompositableClient* aCompositable,
+                                   const SurfaceDescriptorTiles& aTileLayerDescriptor) override;
+
+  bool DestroyInTransaction(PTextureChild* aTexture, bool synchronously) override;
+  bool DestroyInTransaction(PCompositableChild* aCompositable, bool synchronously) override;
+
+  virtual void RemoveTextureFromCompositable(CompositableClient* aCompositable,
+                                             TextureClient* aTexture) 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) override;
+
+  /**
+   * See CompositableForwarder::UseTextures
+   */
+  virtual void UseTextures(CompositableClient* aCompositable,
+                           const nsTArray<TimedTextureClient>& aTextures) override;
+  virtual void UseComponentAlphaTextures(CompositableClient* aCompositable,
+                                         TextureClient* aClientOnBlack,
+                                         TextureClient* aClientOnWhite) override;
+
+  /**
+   * Used for debugging to tell the compositor how long this frame took to paint.
+   */
+  void SendPaintTime(uint64_t aId, TimeDuration aPaintTime);
+
+  /**
+   * 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,
+                      const nsIntRegion& aRegionToClear,
+                      uint64_t aId,
+                      bool aScheduleComposite,
+                      uint32_t aPaintSequenceNumber,
+                      bool aIsRepeatTransaction,
+                      const mozilla::TimeStamp& aTransactionStart,
+                      bool* aSent);
+
+  /**
+   * Set an actor through which layer updates will be pushed.
+   */
+  void SetShadowManager(PLayerTransactionChild* aShadowManager);
+
+  /**
+   * Layout calls here to cache current plugin widget configuration
+   * data. We ship this across with the rest of the layer updates when
+   * we update. Chrome handles applying these changes.
+   */
+  void StorePluginWidgetConfigurations(const nsTArray<nsIWidget::Configuration>&
+                                       aConfigurations);
+
+  void StopReceiveAsyncParentMessge();
+
+  void ClearCachedResources();
+
+  void Composite();
+
+  /**
+   * 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.
+   */
+
+  virtual bool IPCOpen() const 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; }
+
+  void SetPaintSyncId(int32_t aSyncId) { mPaintSyncId = aSyncId; }
+
+  void SetLayerObserverEpoch(uint64_t aLayerObserverEpoch);
+
+  static void PlatformSyncBeforeUpdate();
+
+  virtual bool AllocSurfaceDescriptor(const gfx::IntSize& aSize,
+                                      gfxContentType aContent,
+                                      SurfaceDescriptor* aBuffer) override;
+
+  virtual bool AllocSurfaceDescriptorWithCaps(const gfx::IntSize& aSize,
+                                              gfxContentType aContent,
+                                              uint32_t aCaps,
+                                              SurfaceDescriptor* aBuffer) override;
+
+  virtual void DestroySurfaceDescriptor(SurfaceDescriptor* aSurface) override;
+
+  virtual void UpdateFwdTransactionId() override;
+  virtual uint64_t GetFwdTransactionId() override;
+
+  bool InForwarderThread() override {
+    return NS_IsMainThread();
+  }
+
+  // Returns true if aSurface wraps a Shmem.
+  static bool IsShmem(SurfaceDescriptor* aSurface);
+
+  TextureForwarder* GetTextureForwarder() override { return GetCompositorBridgeChild(); }
+  LayersIPCActor* GetLayersIPCActor() override { return this; }
+
+  ActiveResourceTracker& GetActiveResourceTracker() { return *mActiveResourceTracker.get(); }
+protected:
+  virtual ~ShadowLayerForwarder();
+
+  explicit ShadowLayerForwarder(ClientLayerManager* aClientLayerManager);
+
+#ifdef DEBUG
+  void CheckSurfaceDescriptor(const SurfaceDescriptor* aDescriptor) const;
+#else
+  void CheckSurfaceDescriptor(const SurfaceDescriptor* aDescriptor) const {}
+#endif
+
+  bool InWorkerThread();
+
+  CompositorBridgeChild* GetCompositorBridgeChild();
+
+  RefPtr<LayerTransactionChild> mShadowManager;
+  RefPtr<CompositorBridgeChild> mCompositorBridgeChild;
+
+private:
+
+  ClientLayerManager* mClientLayerManager;
+  Transaction* mTxn;
+  MessageLoop* mMessageLoop;
+  DiagnosticTypes mDiagnosticTypes;
+  bool mIsFirstPaint;
+  bool mWindowOverlayChanged;
+  int32_t mPaintSyncId;
+  InfallibleTArray<PluginWindowData> mPluginWindowData;
+  UniquePtr<ActiveResourceTracker> mActiveResourceTracker;
+};
+
+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