message_loop.h

Go to the documentation of this file.

// Copyright 2013 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
 
#ifndef FLUTTER_FML_MESSAGE_LOOP_H_
#define FLUTTER_FML_MESSAGE_LOOP_H_
 
#include "flutter/fml/macros.h"
#include "flutter/fml/task_runner.h"
 
namespace fml {
 
class TaskRunner;
class MessageLoopImpl;
 
/// An event loop associated with a thread.
///
/// This class is the generic front-end to the MessageLoop, differences in
/// implementation based on the running platform are in the subclasses of
/// flutter::MessageLoopImpl (ex flutter::MessageLoopAndroid).
///
/// For scheduling events on the message loop see flutter::TaskRunner.
///
/// \see fml::TaskRunner
/// \see fml::MessageLoopImpl
/// \see fml::MessageLoopTaskQueues
/// \see fml::Wakeable
class MessageLoop {
 public:
  FML_EMBEDDER_ONLY
  static MessageLoop& GetCurrent();
 
  void Run();
 
  void Terminate();
 
  void AddTaskObserver(intptr_t key, const fml::closure& callback);
 
  void RemoveTaskObserver(intptr_t key);
 
  fml::RefPtr<fml::TaskRunner> GetTaskRunner() const;
 
  // Exposed for the embedder shell which allows clients to poll for events
  // instead of dedicating a thread to the message loop.
  void RunExpiredTasksNow();
 
  static void EnsureInitializedForCurrentThread();
 
  /// Returns true if \p EnsureInitializedForCurrentThread has been called on
  /// this thread already.
  static bool IsInitializedForCurrentThread();
 
  ~MessageLoop();
 
  /// Gets the unique identifier for the TaskQueue associated with the current
  /// thread.
  /// \see fml::MessageLoopTaskQueues
  static TaskQueueId GetCurrentTaskQueueId();
 
 private:
  friend class TaskRunner;
  friend class MessageLoopImpl;
 
  fml::RefPtr<MessageLoopImpl> loop_;
  fml::RefPtr<fml::TaskRunner> task_runner_;
 
  MessageLoop();
 
  fml::RefPtr<MessageLoopImpl> GetLoopImpl() const;
 
  FML_DISALLOW_COPY_AND_ASSIGN(MessageLoop);
};
 
}  // namespace fml
 
#endif  // FLUTTER_FML_MESSAGE_LOOP_H_