base/message_pump_dispatcher.h

// Copyright (c) 2012 The Chromium 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 BASE_MESSAGE_PUMP_DISPATCHER_H
#define BASE_MESSAGE_PUMP_DISPATCHER_H
#pragma once

#include "base/base_export.h"
#include "base/event_types.h"

namespace base {

// Dispatcher is used during a nested invocation of Run to dispatch
// events when |MessageLoop::RunWithDispatcher| is invoked.  If
// |MessageLoop::Run| is invoked, MessageLoop does not dispatch events
// (or invoke TranslateMessage), rather every message is passed to
// Dispatcher's Dispatch method for dispatch. It is up to the
// Dispatcher whether or not to dispatch the event.
//
// The nested loop is exited by either posting a quit, or returning false
// from Dispatch.
class BASE_EXPORT MessagePumpDispatcher {
 public:
  virtual ~MessagePumpDispatcher() {}

  // Dispatches the event. If true is returned processing continues as
  // normal. If false is returned, the nested loop exits immediately.
  virtual bool Dispatch(const NativeEvent& event) = 0;
};

}  // namespace base

#endif  // BASE_MESSAGE_PUMP_DISPATCHER_H