Use a simpler mechanism for tracking which ref layers need device resets. (bug 1333329 part 1, r=rhunt)

gfx/layers/ipc/CompositorBridgeChild.cpp

@@ -384,7 +384,7 @@ CompositorBridgeChild::RecvCompositorUpdated(const uint64_t& aLayersId,
     if (!mCanSend) {
       return IPC_OK();
     }
-    SendAcknowledgeCompositorUpdate(aLayersId);
+    SendAcknowledgeCompositorUpdate(aLayersId, aSeqNo);
   }
   return IPC_OK();
 }

gfx/layers/ipc/CompositorBridgeParent.cpp

@@ -182,7 +182,6 @@ CompositorBridgeParent::LayerTreeState::LayerTreeState()
   , mCrossProcessParent(nullptr)
   , mLayerTree(nullptr)
   , mUpdatedPluginDataAvailable(false)
-  , mPendingCompositorUpdates(0)
 {
 }
 
@@ -1824,9 +1823,9 @@ CompositorBridgeParent::ResetCompositorTask(const nsTArray<LayersBackend>& aBack
       Unused << cpcp->SendCompositorUpdated(layersId, newIdentifier.value(), aSeqNo);
 
       if (LayerTransactionParent* ltp = lts->mLayerTree) {
-        ltp->AddPendingCompositorUpdate();
+        ltp->SetPendingCompositorUpdate(aSeqNo);
       }
-      lts->mPendingCompositorUpdates++;
+      lts->mPendingCompositorUpdate = Some(aSeqNo);
     }
   });
 }

gfx/layers/ipc/CompositorBridgeParent.h

@@ -189,7 +189,7 @@ public:
   virtual mozilla::ipc::IPCResult RecvFlushRendering() override;
   virtual mozilla::ipc::IPCResult RecvForcePresent() override;
 
-  virtual mozilla::ipc::IPCResult RecvAcknowledgeCompositorUpdate(const uint64_t& aLayersId) override {
+  virtual mozilla::ipc::IPCResult RecvAcknowledgeCompositorUpdate(const uint64_t&, const uint64_t&) override {
     MOZ_ASSERT_UNREACHABLE("This message is only sent cross-process");
     return IPC_OK();
   }
@@ -357,9 +357,11 @@ public:
     nsTArray<PluginWindowData> mPluginData;
     bool mUpdatedPluginDataAvailable;
 
-    // Number of times the compositor has been reset without having been
-    // acknowledged by the child.
-    uint32_t mPendingCompositorUpdates;
+    // Most recent device reset sequence number that has not been acknowledged;
+    // this is needed in case a device reset occurs in between allocating a
+    // RefLayer id on the parent, and allocating a PLayerTransaction on the
+    // child.
+    Maybe<uint64_t> mPendingCompositorUpdate;
 
     CompositorController* GetCompositorController() const;
     MetricsSharingController* CrossProcessSharingController() const;

gfx/layers/ipc/CrossProcessCompositorBridgeParent.cpp

@@ -87,7 +87,9 @@ CrossProcessCompositorBridgeParent::AllocPLayerTransactionParent(
     LayerTransactionParent* p = new LayerTransactionParent(lm, this, aId);
     p->AddIPDLReference();
     sIndirectLayerTrees[aId].mLayerTree = p;
-    p->SetPendingCompositorUpdates(state->mPendingCompositorUpdates);
+    if (state->mPendingCompositorUpdate) {
+      p->SetPendingCompositorUpdate(state->mPendingCompositorUpdate.value());
+    }
     return p;
   }
 
@@ -410,16 +412,18 @@ CrossProcessCompositorBridgeParent::GetCompositionManager(LayerTransactionParent
 }
 
 mozilla::ipc::IPCResult
-CrossProcessCompositorBridgeParent::RecvAcknowledgeCompositorUpdate(const uint64_t& aLayersId)
+CrossProcessCompositorBridgeParent::RecvAcknowledgeCompositorUpdate(const uint64_t& aLayersId,
+                                                                    const uint64_t& aSeqNo)
 {
   MonitorAutoLock lock(*sIndirectLayerTreesLock);
   CompositorBridgeParent::LayerTreeState& state = sIndirectLayerTrees[aLayersId];
 
   if (LayerTransactionParent* ltp = state.mLayerTree) {
-    ltp->AcknowledgeCompositorUpdate();
+    ltp->AcknowledgeCompositorUpdate(aSeqNo);
+  }
+  if (state.mPendingCompositorUpdate == Some(aSeqNo)) {
+    state.mPendingCompositorUpdate = Nothing();
   }
-  MOZ_ASSERT(state.mPendingCompositorUpdates > 0);
-  state.mPendingCompositorUpdates--;
   return IPC_OK();
 }
 
@@ -452,7 +456,7 @@ CrossProcessCompositorBridgeParent::AllocPTextureParent(const SurfaceDescriptor&
 
   TextureFlags flags = aFlags;
 
-  if (!state || state->mPendingCompositorUpdates) {
+  if (!state || state->mPendingCompositorUpdate) {
     // The compositor was recreated, and we're receiving layers updates for a
     // a layer manager that will soon be discarded or invalidated. We can't
     // return null because this will mess up deserialization later and we'll

gfx/layers/ipc/CrossProcessCompositorBridgeParent.h

@@ -115,7 +115,9 @@ public:
 
   virtual AsyncCompositionManager* GetCompositionManager(LayerTransactionParent* aParent) override;
   virtual mozilla::ipc::IPCResult RecvRemotePluginsReady()  override { return IPC_FAIL_NO_REASON(this); }
-  virtual mozilla::ipc::IPCResult RecvAcknowledgeCompositorUpdate(const uint64_t& aLayersId) override;
+  virtual mozilla::ipc::IPCResult RecvAcknowledgeCompositorUpdate(
+    const uint64_t& aLayersId,
+    const uint64_t& aSeqNo) override;
 
   void DidComposite(uint64_t aId,
                     TimeStamp& aCompositeStart,

gfx/layers/ipc/LayerTransactionParent.cpp

@@ -59,7 +59,6 @@ LayerTransactionParent::LayerTransactionParent(HostLayerManager* aManager,
   , mChildEpoch(0)
   , mParentEpoch(0)
   , mPendingTransaction(0)
-  , mPendingCompositorUpdates(0)
   , mDestroyed(false)
   , mIPCOpen(false)
 {
@@ -575,7 +574,7 @@ LayerTransactionParent::RecvUpdate(const TransactionInfo& aInfo,
     case Edit::TOpAttachCompositable: {
       const OpAttachCompositable& op = edit.get_OpAttachCompositable();
       RefPtr<CompositableHost> host = FindCompositable(op.compositable());
-      if (mPendingCompositorUpdates) {
+      if (mPendingCompositorUpdate) {
         // Do not attach compositables from old layer trees. Return true since
         // content cannot handle errors.
         return IPC_OK();
@@ -590,7 +589,7 @@ LayerTransactionParent::RecvUpdate(const TransactionInfo& aInfo,
     }
     case Edit::TOpAttachAsyncCompositable: {
       const OpAttachAsyncCompositable& op = edit.get_OpAttachAsyncCompositable();
-      if (mPendingCompositorUpdates) {
+      if (mPendingCompositorUpdate) {
         // Do not attach compositables from old layer trees. Return true since
         // content cannot handle errors.
         return IPC_OK();

gfx/layers/ipc/LayerTransactionParent.h

@@ -97,17 +97,13 @@ public:
     return OtherPid();
   }
 
-  void AddPendingCompositorUpdate() {
-    mPendingCompositorUpdates++;
+  void SetPendingCompositorUpdate(uint64_t aNumber) {
+    mPendingCompositorUpdate = Some(aNumber);
   }
-  void SetPendingCompositorUpdates(uint32_t aCount) {
-    // Only called after construction.
-    MOZ_ASSERT(mPendingCompositorUpdates == 0);
-    mPendingCompositorUpdates = aCount;
-  }
-  void AcknowledgeCompositorUpdate() {
-    MOZ_ASSERT(mPendingCompositorUpdates > 0);
-    mPendingCompositorUpdates--;
+  void AcknowledgeCompositorUpdate(uint64_t aNumber) {
+    if (mPendingCompositorUpdate == Some(aNumber)) {
+      mPendingCompositorUpdate = Nothing();
+    }
   }
 
 protected:
@@ -200,9 +196,9 @@ private:
 
   uint64_t mPendingTransaction;
 
-  // Number of compositor updates we're waiting for the child to
-  // acknowledge.
-  uint32_t mPendingCompositorUpdates;
+  // Not accepting layers updates until we receive an acknowledgement with this
+  // generation number.
+  Maybe<uint64_t> mPendingCompositorUpdate;
 
   // When the widget/frame/browser stuff in this process begins its
   // destruction process, we need to Disconnect() all the currently

gfx/layers/ipc/PCompositorBridge.ipdl

@@ -162,7 +162,7 @@ parent:
 
   // Confirmation that the child has invalidated all its layers, and will not
   // request layers against an old compositor.
-  async AcknowledgeCompositorUpdate(uint64_t id);
+  async AcknowledgeCompositorUpdate(uint64_t aLayersId, uint64_t aSeqNo);
 
   // Child sends the parent a request for fill ratio numbers.
   async RequestOverfill();