Bug 743615 - Handle ImageData in the main thread runtime callbacks. r=bent

dom/base/StructuredCloneTags.h

@@ -44,9 +44,15 @@ namespace dom {
 
 enum StructuredCloneTags {
   SCTAG_BASE = JS_SCTAG_USER_MIN,
+
+  // These tags are used only for main thread structured clone.
   SCTAG_DOM_BLOB,
   SCTAG_DOM_FILE,
   SCTAG_DOM_FILELIST,
+
+  // These tags are used for both main thread and workers.
+  SCTAG_DOM_IMAGEDATA,
+
   SCTAG_DOM_MAX
 };
 

dom/base/nsJSEnvironment.cpp

@@ -86,6 +86,8 @@
 #include "WrapperFactory.h"
 #include "nsGlobalWindow.h"
 #include "nsScriptNameSpaceManager.h"
+#include "StructuredCloneTags.h"
+#include "mozilla/dom/ImageData.h"
 
 #include "nsJSPrincipals.h"
 
@@ -113,6 +115,7 @@
 #include "sampler.h"
 
 using namespace mozilla;
+using namespace mozilla::dom;
 
 const size_t gStackSize = 8192;
 
@@ -3610,7 +3613,36 @@ NS_DOMReadStructuredClone(JSContext* cx,
                           uint32_t data,
                           void* closure)
 {
-  // We don't currently support any extensions to structured cloning.
+  if (tag == SCTAG_DOM_IMAGEDATA) {
+    // Read the information out of the stream.
+    uint32_t width, height;
+    JS::Value dataArray;
+    if (!JS_ReadUint32Pair(reader, &width, &height) ||
+        !JS_ReadTypedArray(reader, &dataArray)) {
+      return nsnull;
+    }
+    MOZ_ASSERT(dataArray.isObject());
+
+    // Construct the ImageData.
+    nsCOMPtr<nsIDOMImageData> imageData = new ImageData(width, height,
+                                                        dataArray.toObject());
+    // Wrap it in a jsval.
+    JSObject* global = JS_GetGlobalForScopeChain(cx);
+    if (!global) {
+      return nsnull;
+    }
+    nsCOMPtr<nsIXPConnectJSObjectHolder> wrapper;
+    JS::Value val;
+    nsresult rv =
+      nsContentUtils::WrapNative(cx, global, imageData, &val,
+                                 getter_AddRefs(wrapper));
+    if (NS_FAILED(rv)) {
+      return nsnull;
+    }
+    return val.toObjectOrNull();
+  }
+
+  // Don't know what this is. Bail.
   nsDOMClassInfo::ThrowJSException(cx, NS_ERROR_DOM_DATA_CLONE_ERR);
   return nsnull;
 }
@@ -3621,7 +3653,30 @@ NS_DOMWriteStructuredClone(JSContext* cx,
                            JSObject* obj,
                            void *closure)
 {
-  // We don't currently support any extensions to structured cloning.
+  nsCOMPtr<nsIXPConnectWrappedNative> wrappedNative;
+  nsContentUtils::XPConnect()->
+    GetWrappedNativeOfJSObject(cx, obj, getter_AddRefs(wrappedNative));
+  nsISupports *native = wrappedNative ? wrappedNative->Native() : nsnull;
+
+  nsCOMPtr<nsIDOMImageData> imageData = do_QueryInterface(native);
+  if (imageData) {
+    // Prepare the ImageData internals.
+    PRUint32 width, height;
+    JS::Value dataArray;
+    if (NS_FAILED(imageData->GetWidth(&width)) ||
+        NS_FAILED(imageData->GetHeight(&height)) ||
+        NS_FAILED(imageData->GetData(cx, &dataArray)))
+    {
+      return false;
+    }
+
+    // Write the internals to the stream.
+    return JS_WriteUint32Pair(writer, SCTAG_DOM_IMAGEDATA, 0) &&
+           JS_WriteUint32Pair(writer, width, height) &&
+           JS_WriteTypedArray(writer, dataArray);
+  }
+
+  // Don't know what this is. Bail.
   nsDOMClassInfo::ThrowJSException(cx, NS_ERROR_DOM_DATA_CLONE_ERR);
   return JS_FALSE;
 }