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
  18 // To embed Gin, first initialize gin using IsolateHolder::Initialize and then
  19 // create an instance of IsolateHolder to hold the v8::Isolate in which you
  20 // will execute JavaScript. You might wish to subclass IsolateHolder if you
  21 // want to tie more state to the lifetime of the isolate.
  22 class GIN_EXPORT IsolateHolder {
  23  public:
  24   // Controls whether or not V8 should only accept strict mode scripts.
  25   enum ScriptMode {
  26     kNonStrictMode,
  27     kStrictMode
  28   };
  29
  30   IsolateHolder();
  31   ~IsolateHolder();
  32
  33   // Should be invoked once before creating IsolateHolder instances to
  34   // initialize V8 and Gin. In case V8_USE_EXTERNAL_STARTUP_DATA is defined,
  35   // V8's initial snapshot should be loaded (by calling LoadV8Snapshot or
  36   // LoadV8SnapshotFd) before calling Initialize.
  37   static void Initialize(ScriptMode mode,
  38                          v8::ArrayBuffer::Allocator* allocator);
  39
  40   v8::Isolate* isolate() { return isolate_; }
  41
  42   // The implementations of Object.observe() and Promise enqueue v8 Microtasks
  43   // that should be executed just before control is returned to the message
  44   // loop. This method adds a MessageLoop TaskObserver which runs any pending
  45   // Microtasks each time a Task is completed. This method should be called
  46   // once, when a MessageLoop is created and it should be called on the
  47   // MessageLoop's thread.
  48   void AddRunMicrotasksObserver();
  49
  50   // This method should also only be called once, and on the MessageLoop's
  51   // thread.
  52   void RemoveRunMicrotasksObserver();
  53
  54 #if defined(V8_USE_EXTERNAL_STARTUP_DATA)
  55   static const char kNativesFileName[];
  56   static const char kSnapshotFileName[];
  57
  58   static bool LoadV8SnapshotFd(int natives_fd,
  59                                int64 natives_offset,
  60                                int64 natives_size,
  61                                int snapshot_fd,
  62                                int64 snapshot_offset,
  63                                int64 snapshot_size);
  64   static bool LoadV8Snapshot();
  65 #endif  // V8_USE_EXTERNAL_STARTUP_DATA
  66   static void GetV8ExternalSnapshotData(const char** natives_data_out,
  67                                         int* natives_size_out,
  68                                         const char** snapshot_data_out,
  69                                         int* snapshot_size_out);
  70
  71  private:
  72   v8::Isolate* isolate_;
  73   scoped_ptr<PerIsolateData> isolate_data_;
  74   scoped_ptr<RunMicrotasksObserver> task_observer_;
  75
  76   DISALLOW_COPY_AND_ASSIGN(IsolateHolder);
  77 };
  78
  79 }  // namespace gin
  80
  81 #endif  // GIN_PUBLIC_ISOLATE_HOLDER_H_