Externalization API for ArrayBuffer

src/d8.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1030 matching lines @@
   chars[size] = '\0';
   for (int i = 0; i < size;) {
     int read = static_cast<int>(fread(&chars[i], 1, size - i, file));
     i += read;
   }
   fclose(file);
   *size_out = size;
   return chars;
 }
 
+static void ReadBufferWeakCallback(v8::Isolate* isolate,
+                                   Persistent<Value>* object,
+                                   uint8_t* data) {
+  size_t byte_length = ArrayBuffer::Cast(**object)->ByteLength();
+  isolate->AdjustAmountOfExternalAllocatedMemory(
+      -static_cast<intptr_t>(byte_length));
+
+  delete[] data;
+  object->Dispose(isolate);
+}
 
 Handle<Value> Shell::ReadBuffer(const Arguments& args) {
   ASSERT(sizeof(char) == sizeof(uint8_t));  // NOLINT
   String::Utf8Value filename(args[0]);
   int length;
   if (*filename == NULL) {
     return Throw("Error loading file");
   }
 
+  Isolate* isolate = args.GetIsolate();
   uint8_t* data = reinterpret_cast<uint8_t*>(
       ReadChars(args.GetIsolate(), *filename, &length));
   if (data == NULL) {
     return Throw("Error reading file");
   }
-  Handle<v8::ArrayBuffer> buffer = ArrayBuffer::New(length);
-  memcpy(buffer->Data(), data, length);
-  delete[] data;
+  Handle<v8::ArrayBuffer> buffer = ArrayBuffer::New(data, length);
+  v8::Persistent<v8::Value> weak_handle =
+      v8::Persistent<v8::Value>::New(isolate, buffer);
+  weak_handle.MakeWeak(isolate, data, ReadBufferWeakCallback);
+  weak_handle.MarkIndependent();
+  isolate->AdjustAmountOfExternalAllocatedMemory(length);
+
   return buffer;
 }
 
 
 #ifndef V8_SHARED
 static char* ReadToken(char* data, char token) {
   char* next = i::OS::StrChr(data, token);
   if (next != NULL) {
     *next = '\0';
     return (next + 1);
@@ skipping 524 matching lines @@
 }
 
 }  // namespace v8
 
 
 #ifndef GOOGLE3
 int main(int argc, char* argv[]) {
   return v8::Shell::Main(argc, argv);
 }
 #endif