gin/public/isolate_holder.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef GIN_PUBLIC_ISOLATE_HOLDER_H_
   6 #define GIN_PUBLIC_ISOLATE_HOLDER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "gin/gin_export.h"
  11 #include "v8/include/v8.h"
  12
  13 namespace gin {
  14
  15 class PerIsolateData;
  16 class RunMicrotasksObserver;
  17 class V8IsolateMemoryDumpProvider;
  18
  19 // To embed Gin, first initialize gin using IsolateHolder::Initialize and then
  20 // create an instance of IsolateHolder to hold the v8::Isolate in which you
  21 // will execute JavaScript. You might wish to subclass IsolateHolder if you
  22 // want to tie more state to the lifetime of the isolate.
  23 class GIN_EXPORT IsolateHolder {
  24  public:
  25   // Controls whether or not V8 should only accept strict mode scripts.
  26   enum ScriptMode {
  27     kNonStrictMode,
  28     kStrictMode
  29   };
  30
  31   // Stores whether the client uses v8::Locker to access the isolate.
  32   enum AccessMode {
  33     kSingleThread,
  34     kUseLocker
  35   };
  36
  37   IsolateHolder();
  38   explicit IsolateHolder(AccessMode access_mode);
  39   ~IsolateHolder();
  40
  41   // Should be invoked once before creating IsolateHolder instances to
  42   // initialize V8 and Gin. In case V8_USE_EXTERNAL_STARTUP_DATA is
  43   // defined, V8's initial snapshot should be loaded (by calling
  44   // V8Initializer::LoadV8SnapshotFromFD or
  45   // V8Initializer::LoadV8Snapshot) before calling this method.
  46   static void Initialize(ScriptMode mode,
  47                          v8::ArrayBuffer::Allocator* allocator);
  48
  49   v8::Isolate* isolate() { return isolate_; }
  50
  51   // The implementations of Object.observe() and Promise enqueue v8 Microtasks
  52   // that should be executed just before control is returned to the message
  53   // loop. This method adds a MessageLoop TaskObserver which runs any pending
  54   // Microtasks each time a Task is completed. This method should be called
  55   // once, when a MessageLoop is created and it should be called on the
  56   // MessageLoop's thread.
  57   void AddRunMicrotasksObserver();
  58
  59   // This method should also only be called once, and on the MessageLoop's
  60   // thread.
  61   void RemoveRunMicrotasksObserver();
  62
  63   // This method returns if v8::Locker is needed to access isolate.
  64   AccessMode access_mode() const { return access_mode_; }
  65
  66  private:
  67   v8::Isolate* isolate_;
  68   scoped_ptr<PerIsolateData> isolate_data_;
  69   scoped_ptr<RunMicrotasksObserver> task_observer_;
  70   scoped_ptr<V8IsolateMemoryDumpProvider> isolate_memory_dump_provider_;
  71   AccessMode access_mode_;
  72
  73   DISALLOW_COPY_AND_ASSIGN(IsolateHolder);
  74 };
  75
  76 }  // namespace gin
  77
  78 #endif  // GIN_PUBLIC_ISOLATE_HOLDER_H_