Bug 1184557 - part 2 - StructuredCloneHelperInternal::Shutdown, r=smaug

dom/base/Console.cpp

@@ -207,6 +207,8 @@ public:
   virtual
   ~ConsoleRunnable()
   {
+    // Shutdown the StructuredCloneHelperInternal class.
+    Shutdown();
   }
 
   bool

dom/base/StructuredCloneHelper.cpp

@@ -89,7 +89,7 @@ void
 StructuredCloneCallbacksError(JSContext* aCx,
                               uint32_t aErrorId)
 {
-  NS_WARNING("Failed to clone data for the Console API in workers.");
+  NS_WARNING("Failed to clone data.");
 }
 
 const JSStructuredCloneCallbacks gCallbacks = {
@@ -105,11 +105,36 @@ const JSStructuredCloneCallbacks gCallbacks = {
 
 // StructuredCloneHelperInternal class
 
+StructuredCloneHelperInternal::StructuredCloneHelperInternal()
+#ifdef DEBUG
+  : mShutdownCalled(false)
+#endif
+{}
+
+StructuredCloneHelperInternal::~StructuredCloneHelperInternal()
+{
+#ifdef DEBUG
+  MOZ_ASSERT(mShutdownCalled);
+#endif
+}
+
+void
+StructuredCloneHelperInternal::Shutdown()
+{
+#ifdef DEBUG
+  MOZ_ASSERT(!mShutdownCalled, "Shutdown already called!");
+  mShutdownCalled = true;
+#endif
+
+  mBuffer = nullptr;
+}
+
 bool
 StructuredCloneHelperInternal::Write(JSContext* aCx,
                                      JS::Handle<JS::Value> aValue)
 {
   MOZ_ASSERT(!mBuffer, "Double Write is not allowed");
+  MOZ_ASSERT(!mShutdownCalled, "This method cannot be called after Shutdown.");
 
   mBuffer = new JSAutoStructuredCloneBuffer(&gCallbacks, this);
   return mBuffer->write(aCx, aValue, &gCallbacks, this);
@@ -121,6 +146,7 @@ StructuredCloneHelperInternal::Write(JSContext* aCx,
                                      JS::Handle<JS::Value> aTransfer)
 {
   MOZ_ASSERT(!mBuffer, "Double Write is not allowed");
+  MOZ_ASSERT(!mShutdownCalled, "This method cannot be called after Shutdown.");
 
   mBuffer = new JSAutoStructuredCloneBuffer(&gCallbacks, this);
   return mBuffer->write(aCx, aValue, aTransfer, &gCallbacks, this);
@@ -131,6 +157,7 @@ StructuredCloneHelperInternal::Read(JSContext* aCx,
                                     JS::MutableHandle<JS::Value> aValue)
 {
   MOZ_ASSERT(mBuffer, "Read() without Write() is not allowed.");
+  MOZ_ASSERT(!mShutdownCalled, "This method cannot be called after Shutdown.");
 
   bool ok = mBuffer->read(aCx, aValue, &gCallbacks, this);
   mBuffer = nullptr;
@@ -178,7 +205,9 @@ StructuredCloneHelper::StructuredCloneHelper(uint32_t aFlags)
 {}
 
 StructuredCloneHelper::~StructuredCloneHelper()
-{}
+{
+  Shutdown();
+}
 
 bool
 StructuredCloneHelper::Write(JSContext* aCx,

dom/base/StructuredCloneHelper.h

@@ -17,6 +17,9 @@ namespace dom {
 class StructuredCloneHelperInternal
 {
 public:
+  StructuredCloneHelperInternal();
+  virtual ~StructuredCloneHelperInternal();
+
   // These methods should be implemented in order to clone data.
   // Read more documentation in js/public/StructuredClone.h.
 
@@ -29,6 +32,12 @@ public:
                              JSStructuredCloneWriter* aWriter,
                              JS::Handle<JSObject*> aObj) = 0;
 
+  // This method has to be called when this object is not needed anymore.
+  // It will free memory and the buffer. This has to be called because
+  // otherwise the buffer will be freed in the DTOR of this class and at that
+  // point we cannot use the overridden methods.
+  void Shutdown();
+
   // If these 3 methods are not implement, transfering objects will not be
   // allowed.
 
@@ -69,6 +78,10 @@ public:
 
 protected:
   nsAutoPtr<JSAutoStructuredCloneBuffer> mBuffer;
+
+#ifdef DEBUG
+  bool mShutdownCalled;
+#endif
 };
 
 class MessagePortBase;