Bug 1333968 - Add GetSpecificMessageEventTarget method to change the …

…event target for specific IPC messages (r=dvander) MozReview-Commit-ID: EIyfNgKWCRo
dothq · Apr 11, 2017 · 5203251 · 5203251
1 parent ea4f15c
commit 5203251
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Showing 2 changed files with 15 additions and 1 deletion.
diff --git a/ipc/glue/ProtocolUtils.cpp b/ipc/glue/ProtocolUtils.cpp
@@ -801,7 +801,9 @@ IToplevelProtocol::GetMessageEventTarget(const Message& aMsg)
 {
   int32_t route = aMsg.routing_id();
 
-  MutexAutoLock lock(mEventTargetMutex);
+  Maybe<MutexAutoLock> lock;
+  lock.emplace(mEventTargetMutex);
+
   nsCOMPtr<nsIEventTarget> target = mEventTargetMap.Lookup(route);
 
   if (aMsg.is_constructor()) {
@@ -820,6 +822,11 @@ IToplevelProtocol::GetMessageEventTarget(const Message& aMsg)
     }
 
     mEventTargetMap.AddWithID(target, handle.mId);
+  } else if (!target) {
+    // We don't need the lock after this point.
+    lock.reset();
+
+    target = GetSpecificMessageEventTarget(aMsg);
   }
 
   return target.forget();

diff --git a/ipc/glue/ProtocolUtils.h b/ipc/glue/ProtocolUtils.h
@@ -376,9 +376,16 @@ class IToplevelProtocol : public IProtocol
     GetActorEventTarget();
 
 protected:
+    // Override this method in top-level protocols to change the event target
+    // for a new actor (and its sub-actors).
     virtual already_AddRefed<nsIEventTarget>
     GetConstructedEventTarget(const Message& aMsg) { return nullptr; }
 
+    // Override this method in top-level protocols to change the event target
+    // for specific messages.
+    virtual already_AddRefed<nsIEventTarget>
+    GetSpecificMessageEventTarget(const Message& aMsg) { return nullptr; }
+
     virtual void SetEventTargetForActorInternal(IProtocol* aActor, nsIEventTarget* aEventTarget);
 
     virtual already_AddRefed<nsIEventTarget>