Reland of: Make Imagebitmap Transferable

third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp

Index: third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp
diff --git a/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp b/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp
index bc1e32f4a090fdb4f9d5092eab00f52cbc79609f..79af5805b6c48eb96b565987d076dc260cc8b4bd 100644
--- a/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp
+++ b/third_party/WebKit/Source/bindings/core/v8/SerializedScriptValue.cpp
@@ -38,6 +38,7 @@
 #include "bindings/core/v8/ScriptValueSerializer.h"
 #include "bindings/core/v8/SerializedScriptValueFactory.h"
 #include "bindings/core/v8/V8ArrayBuffer.h"
+#include "bindings/core/v8/V8ImageBitmap.h"
 #include "bindings/core/v8/V8MessagePort.h"
 #include "bindings/core/v8/V8SharedArrayBuffer.h"
 #include "core/dom/ExceptionCode.h"
@@ -101,6 +102,31 @@ static void acculumateArrayBuffersForAllWorlds(v8::Isolate* isolate, DOMArrayBuf
     }
 }
 
+PassOwnPtr<SerializedScriptValue::ImageBitmapContentsArray> SerializedScriptValue::createImageBitmaps(v8::Isolate* isolate, ImageBitmapArray& imageBitmaps, ExceptionState& exceptionState)
+{
+    ASSERT(imageBitmaps.size());
+
+    for (size_t i = 0; i < imageBitmaps.size(); i++) {
+        if (imageBitmaps[i]->isNeutered()) {
+            exceptionState.throwDOMException(DataCloneError, "ImageBitmap at index " + String::number(i) + " is already neutered.");
+            return nullptr;
+        }
+    }
+
+    OwnPtr<ImageBitmapContentsArray> contents = adoptPtr(new ImageBitmapContentsArray(imageBitmaps.size()));
+    WillBeHeapHashSet<RawPtrWillBeMember<ImageBitmap>> visited;
+    int validIdx = 0;
+    for (size_t i = 0; i < imageBitmaps.size(); i++) {

[sof, 2015/11/16 19:22:34]

The code here works fine, but I wonder if we can shorten it up a bit:

  ...
  OwnPtr<ImageBitmapContentsArray> contents = adoptPtr(new
ImageBitmapContentsArray);
  for (ImageBitmap* imageBitmap : imageBitmaps) {
      if (visited.contains(imageBitmap))
          continue;
      visited.add(imageBitmap);
      contents->append(imageBitmap->transfer());
  }
  return contents.release();

i.e., I don't think it is worth being exactingly precise about pre-sizing
'contents', nor shrink its backing buffer to exactly fit afterwards.

[xidachen, 2015/11/16 20:15:50]

Thank you for the comments. I think you made a good point because the number of
elements in the vector is likely small in most cases, so it is not worth to
pre-allocate and then shrink.

+        if (visited.contains(imageBitmaps[i].get()))
+            continue;
+        visited.add(imageBitmaps[i].get());
+        contents->at(validIdx++) = imageBitmaps[i]->transfer();
+    }
+    contents.get()->remove(validIdx, imageBitmaps.size()-validIdx);
+    return contents.release();
+}
+
+
 PassOwnPtr<SerializedScriptValue::ArrayBufferContentsArray> SerializedScriptValue::createArrayBuffers(v8::Isolate* isolate, ArrayBufferArray& arrayBuffers, ExceptionState& exceptionState)
 {
     ASSERT(arrayBuffers.size());
@@ -169,11 +195,12 @@ v8::Local<v8::Value> SerializedScriptValue::deserialize(v8::Isolate* isolate, Me
     return SerializedScriptValueFactory::instance().deserialize(this, isolate, messagePorts, blobInfo);
 }
 
-bool SerializedScriptValue::extractTransferables(v8::Isolate* isolate, v8::Local<v8::Value> value, int argumentIndex, MessagePortArray& ports, ArrayBufferArray& arrayBuffers, ExceptionState& exceptionState)
+bool SerializedScriptValue::extractTransferables(v8::Isolate* isolate, v8::Local<v8::Value> value, int argumentIndex, MessagePortArray& ports, ArrayBufferArray& arrayBuffers, ImageBitmapArray& imageBitmaps, ExceptionState& exceptionState)
 {
     if (isUndefinedOrNull(value)) {
         ports.resize(0);
         arrayBuffers.resize(0);
+        imageBitmaps.resize(0);
         return true;
     }
 
@@ -222,6 +249,13 @@ bool SerializedScriptValue::extractTransferables(v8::Isolate* isolate, v8::Local
                 return false;
             }
             arrayBuffers.append(sharedArrayBuffer.release());
+        } else if (V8ImageBitmap::hasInstance(transferrable, isolate)) {
+            RefPtrWillBeRawPtr<ImageBitmap> imageBitmap = V8ImageBitmap::toImpl(v8::Local<v8::Object>::Cast(transferrable));
+            if (imageBitmaps.contains(imageBitmap)) {
+                exceptionState.throwDOMException(DataCloneError, "ImageBitmap at index " + String::number(i) + " is a duplicate of an earlier ImageBitmap.");
+                return false;
+            }
+            imageBitmaps.append(imageBitmap.release());
         } else {
             exceptionState.throwTypeError("Value at index " + String::number(i) + " does not have a transferable type.");
             return false;
@@ -259,4 +293,9 @@ void SerializedScriptValue::transferArrayBuffers(v8::Isolate* isolate, ArrayBuff
     m_arrayBufferContentsArray = createArrayBuffers(isolate, arrayBuffers, exceptionState);
 }
 
+void SerializedScriptValue::transferImageBitmaps(v8::Isolate* isolate, ImageBitmapArray& imageBitmaps, ExceptionState& exceptionState)
+{
+    m_imageBitmapContentsArray = createImageBitmaps(isolate, imageBitmaps, exceptionState);
+}
+
 } // namespace blink