Merge from Chromium at DEPS revision 237746

This commit was generated by merge_to_master.py.

Change-Id: I8997af4cddfeb09a7c26f7e8e672c712cab461ea

1 files changed, 169 insertions, 0 deletions

diff --git a/gin/array_buffer.cc b/gin/array_buffer.cc
new file mode 100644
index 0000000000..e8e234e5db
--- /dev/null
+++ b/gin/array_buffer.cc
@@ -0,0 +1,169 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "gin/array_buffer.h"
+
+#include <stdlib.h>
+
+namespace gin {
+
+COMPILE_ASSERT(V8_ARRAY_BUFFER_INTERNAL_FIELD_COUNT == 2,
+               array_buffers_must_have_two_internal_fields);
+
+static const int kBufferViewPrivateIndex = 0;
+
+// ArrayBufferAllocator -------------------------------------------------------
+
+void* ArrayBufferAllocator::Allocate(size_t length) {
+  return calloc(1, length);
+}
+
+void* ArrayBufferAllocator::AllocateUninitialized(size_t length) {
+  return malloc(length);
+}
+
+void ArrayBufferAllocator::Free(void* data, size_t length) {
+  free(data);
+}
+
+ArrayBufferAllocator* ArrayBufferAllocator::SharedInstance() {
+  static ArrayBufferAllocator* instance = new ArrayBufferAllocator();
+  return instance;
+}
+
+// ArrayBuffer::Private -------------------------------------------------------
+
+// This class exists to solve a tricky lifetime problem. The V8 API doesn't
+// want to expose a direct view into the memory behind an array buffer because
+// V8 might deallocate that memory during garbage collection. Instead, the V8
+// API forces us to externalize the buffer and take ownership of the memory.
+// In order to know when to free the memory, we need to figure out both when
+// we're done with it and when V8 is done with it.
+//
+// To determine whether we're done with the memory, every view we have into
+// the array buffer takes a reference to the ArrayBuffer::Private object that
+// actually owns the memory. To determine when V8 is done with the memory, we
+// open a weak handle to the ArrayBuffer object. When we receive the weak
+// callback, we know the object is about to be garbage collected and we can
+// drop V8's implied reference to the memory.
+//
+// The final subtlety is that we need every ArrayBuffer into the same array
+// buffer to AddRef the same ArrayBuffer::Private. To make that work, we store
+// a pointer to the ArrayBuffer::Private object in an internal field of the
+// ArrayBuffer object.
+//
+class ArrayBuffer::Private : public base::RefCounted<ArrayBuffer::Private> {
+ public:
+  static scoped_refptr<Private> From(v8::Isolate* isolate,
+                                     v8::Handle<v8::ArrayBuffer> array);
+
+  void* buffer() const { return buffer_; }
+  size_t length() const { return length_; }
+
+ private:
+  friend class base::RefCounted<Private>;
+
+  Private(v8::Isolate* isolate, v8::Handle<v8::ArrayBuffer> array);
+  ~Private();
+
+  static void WeakCallback(
+      const v8::WeakCallbackData<v8::ArrayBuffer, Private>& data);
+
+  v8::Persistent<v8::ArrayBuffer> array_buffer_;
+  scoped_refptr<Private> self_reference_;
+  void* buffer_;
+  size_t length_;
+};
+
+scoped_refptr<ArrayBuffer::Private> ArrayBuffer::Private::From(
+    v8::Isolate* isolate, v8::Handle<v8::ArrayBuffer> array) {
+  if (array->IsExternal()) {
+    return make_scoped_refptr(static_cast<Private*>(
+        array->GetAlignedPointerFromInternalField(kBufferViewPrivateIndex)));
+  }
+  return make_scoped_refptr(new Private(isolate, array));
+}
+
+ArrayBuffer::Private::Private(v8::Isolate* isolate,
+                              v8::Handle<v8::ArrayBuffer> array)
+    : array_buffer_(isolate, array) {
+  // Take ownership of the array buffer.
+  v8::ArrayBuffer::Contents contents = array->Externalize();
+  buffer_ = contents.Data();
+  length_ = contents.ByteLength();
+
+  array->SetAlignedPointerInInternalField(kBufferViewPrivateIndex, this);
+
+  self_reference_ = this;  // Cleared in WeakCallback.
+  array_buffer_.SetWeak(this, WeakCallback);
+}
+
+ArrayBuffer::Private::~Private() {
+  ArrayBufferAllocator::SharedInstance()->Free(buffer_, length_);
+}
+
+void ArrayBuffer::Private::WeakCallback(
+    const v8::WeakCallbackData<v8::ArrayBuffer, Private>& data) {
+  Private* parameter = data.GetParameter();
+  parameter->array_buffer_.Reset();
+  parameter->self_reference_ = NULL;
+}
+
+// ArrayBuffer ----------------------------------------------------------------
+
+ArrayBuffer::ArrayBuffer()
+    : bytes_(0),
+      num_bytes_(0) {
+}
+
+ArrayBuffer::ArrayBuffer(v8::Isolate* isolate,
+                         v8::Handle<v8::ArrayBuffer> array) {
+  private_ = ArrayBuffer::Private::From(isolate, array);
+  bytes_ = private_->buffer();
+  num_bytes_ = private_->length();
+}
+
+ArrayBuffer::~ArrayBuffer() {
+}
+
+// Converter<ArrayBuffer> -----------------------------------------------------
+
+bool Converter<ArrayBuffer>::FromV8(v8::Isolate* isolate,
+                                    v8::Handle<v8::Value> val,
+                                    ArrayBuffer* out) {
+  if (!val->IsArrayBuffer())
+    return false;
+  *out = ArrayBuffer(isolate, v8::Handle<v8::ArrayBuffer>::Cast(val));
+  return true;
+}
+
+// ArrayBufferView ------------------------------------------------------------
+
+ArrayBufferView::ArrayBufferView()
+    : offset_(0),
+      num_bytes_(0) {
+}
+
+ArrayBufferView::ArrayBufferView(v8::Isolate* isolate,
+                                 v8::Handle<v8::ArrayBufferView> view)
+    : array_buffer_(isolate, view->Buffer()),
+      offset_(view->ByteOffset()),
+      num_bytes_(view->ByteLength()) {
+}
+
+ArrayBufferView::~ArrayBufferView() {
+}
+
+// Converter<ArrayBufferView> -------------------------------------------------
+
+bool Converter<ArrayBufferView>::FromV8(v8::Isolate* isolate,
+                                        v8::Handle<v8::Value> val,
+                                        ArrayBufferView* out) {
+  if (!val->IsArrayBufferView())
+    return false;
+  *out = ArrayBufferView(isolate, v8::Handle<v8::ArrayBufferView>::Cast(val));
+  return true;
+}
+
+}  // namespace gin