- A prototype which allows to expose CanvasPixelArray functionality...

src/objects-inl.h

Index: src/objects-inl.h
===================================================================
--- src/objects-inl.h	(revision 2544)
+++ src/objects-inl.h	(working copy)
@@ -321,6 +321,12 @@
 }
 
 
+bool Object::IsPixelArray() {
+  return Object::IsHeapObject() &&
+      HeapObject::cast(this)->map()->instance_type() == PIXEL_ARRAY_TYPE;
+}
+
+
 bool Object::IsFailure() {
   return HAS_FAILURE_TAG(this);
 }
@@ -1043,9 +1049,24 @@
 
 
 ACCESSORS(JSObject, properties, FixedArray, kPropertiesOffset)
-ACCESSORS(JSObject, elements, FixedArray, kElementsOffset)
 
 
+Array* JSObject::elements() {
+  Object* array = READ_FIELD(this, kElementsOffset);
+  // In the assert below Dictionary is covered under FixedArray.
+  ASSERT(array->IsFixedArray() || array->IsPixelArray());
+  return reinterpret_cast<Array*>(array);
+}
+
+
+void JSObject::set_elements(Array* value, WriteBarrierMode mode) {
+  // In the assert below Dictionary is covered under FixedArray.
+  ASSERT(value->IsFixedArray() || value->IsPixelArray());
+  WRITE_FIELD(this, kElementsOffset, value);
+  CONDITIONAL_WRITE_BARRIER(this, kElementsOffset, mode);
+}
+
+
 void JSObject::initialize_properties() {
   ASSERT(!Heap::InNewSpace(Heap::empty_fixed_array()));
   WRITE_FIELD(this, kPropertiesOffset, Heap::empty_fixed_array());
@@ -1502,6 +1523,7 @@
 CAST_ACCESSOR(JSRegExp)
 CAST_ACCESSOR(Proxy)
 CAST_ACCESSOR(ByteArray)
+CAST_ACCESSOR(PixelArray)
 CAST_ACCESSOR(Struct)
 
 
@@ -1860,6 +1882,32 @@
 }
 
 
+uint8_t* PixelArray::external_pointer() {
+  intptr_t ptr = READ_INTPTR_FIELD(this, kExternalPointerOffset);
+  return reinterpret_cast<uint8_t*>(ptr);
+}
+
+
+void PixelArray::set_external_pointer(uint8_t* value, WriteBarrierMode mode) {
+  intptr_t ptr = reinterpret_cast<intptr_t>(value);
+  WRITE_INTPTR_FIELD(this, kExternalPointerOffset, ptr);
+}
+
+
+uint8_t PixelArray::get(int index) {
+  ASSERT((index >= 0) && (index < this->length()));
+  uint8_t* ptr = external_pointer();
+  return ptr[index];
+}
+
+
+void PixelArray::set(int index, uint8_t value) {
+  ASSERT((index >= 0) && (index < this->length()));
+  uint8_t* ptr = external_pointer();
+  ptr[index] = value;
+}
+
+
 int Map::instance_size() {
   return READ_BYTE_FIELD(this, kInstanceSizeOffset) << kPointerSizeLog2;
 }
@@ -2523,11 +2571,36 @@
 }
 
 
+JSObject::ElementsKind JSObject::GetElementsKind() {
+  Array* array = elements();
+  if (array->IsFixedArray()) {
+    // FAST_ELEMENTS or DICTIONARY_ELEMENTS are both stored in a FixedArray.
+    if (array->map() == Heap::fixed_array_map()) {
+      return FAST_ELEMENTS;
+    }
+    ASSERT(array->IsDictionary());
+    return DICTIONARY_ELEMENTS;
+  }
+  ASSERT(array->IsPixelArray());
+  return PIXEL_ELEMENTS;
+}
+
+
 bool JSObject::HasFastElements() {
-  return !elements()->IsDictionary();
+  return GetElementsKind() == FAST_ELEMENTS;
 }
 
 
+bool JSObject::HasDictionaryElements() {
+  return GetElementsKind() == DICTIONARY_ELEMENTS;
+}
+
+
+bool JSObject::HasPixelElements() {
+  return GetElementsKind() == PIXEL_ELEMENTS;
+}
+
+
 bool JSObject::HasNamedInterceptor() {
   return map()->has_named_interceptor();
 }
@@ -2545,7 +2618,7 @@
 
 
 NumberDictionary* JSObject::element_dictionary() {
-  ASSERT(!HasFastElements());
+  ASSERT(HasDictionaryElements());
   return NumberDictionary::cast(elements());
 }