Support externalized ArrayBuffer for node::Buffer

atom/renderer/node_array_buffer_bridge.cc

@@ -0,0 +1,66 @@
+// Copyright (c) 2015 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/renderer/node_array_buffer_bridge.h"
+
+#include "base/basictypes.h"
+#include "atom/common/node_includes.h"
+#include "native_mate/converter.h"
+#include "third_party/WebKit/public/web/WebArrayBuffer.h"
+#include "third_party/WebKit/public/web/WebArrayBufferConverter.h"
+
+namespace atom {
+
+namespace {
+
+// global.Uint8Array;
+v8::Local<v8::Function> GetUint8ArrayConstructor(
+    v8::Isolate* isolate, v8::Local<v8::Context> context) {
+  v8::Local<v8::Value> constructor = context->Global()->Get(
+      mate::StringToV8(isolate, "Uint8Array"));
+  return v8::Local<v8::Function>::Cast(constructor);
+}
+
+// new ArrayBuffer(size);
+v8::Local<v8::ArrayBuffer> BlinkArrayBufferNew(
+    v8::Isolate* isolate, size_t size) {
+  blink::WebArrayBuffer buffer = blink::WebArrayBuffer::create(size, 1);
+  return v8::Local<v8::ArrayBuffer>::Cast(
+      blink::WebArrayBufferConverter::toV8Value(
+          &buffer, isolate->GetCurrentContext()->Global(), isolate));
+}
+
+// new ArrayBuffer(data, size);
+v8::Local<v8::ArrayBuffer> BlinkArrayBufferNewWith(
+    v8::Isolate* isolate, void* data, size_t size) {
+  blink::WebArrayBuffer buffer = blink::WebArrayBuffer::createExternal(
+      data, size);
+  return v8::Local<v8::ArrayBuffer>::Cast(
+      blink::WebArrayBufferConverter::toV8Value(
+          &buffer, isolate->GetCurrentContext()->Global(), isolate));
+}
+
+// new Uint8Array(array_buffer, offset, size);
+v8::Local<v8::Uint8Array> BlinkUint8ArrayNew(
+    v8::Local<v8::ArrayBuffer> ab, size_t offset, size_t size) {
+  // Use the DOM's Uint8Array constructor to create Uint8Array.
+  v8::Local<v8::Context> context = ab->CreationContext();
+  v8::Isolate* isolate = context->GetIsolate();
+  v8::Local<v8::Function> constructor =
+      GetUint8ArrayConstructor(isolate, context);
+  v8::Local<v8::Value> args[] = {
+      ab, mate::ConvertToV8(isolate, offset), mate::ConvertToV8(isolate, size)
+  };
+  return v8::Local<v8::Uint8Array>::Cast(constructor->NewInstance(
+      context, arraysize(args), args).ToLocalChecked());
+}
+
+}  // namespace
+
+void OverrideNodeArrayBuffer() {
+  node::Buffer::SetArrayBufferCreator(
+      BlinkArrayBufferNew, BlinkArrayBufferNewWith, BlinkUint8ArrayNew);
+}
+
+}  // namespace atom