base/message_pump_dispatcher.h

   1 // Copyright (c) 2012 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 BASE_MESSAGE_PUMP_DISPATCHER_H
   6 #define BASE_MESSAGE_PUMP_DISPATCHER_H
   7
   8 #include "base/base_export.h"
   9 #include "base/event_types.h"
  10
  11 namespace base {
  12
  13 // Dispatcher is used during a nested invocation of Run to dispatch events when
  14 // |RunLoop(dispatcher).Run()| is used.  If |RunLoop().Run()| is invoked,
  15 // MessageLoop does not dispatch events (or invoke TranslateMessage), rather
  16 // every message is passed to Dispatcher's Dispatch method for dispatch. It is
  17 // up to the Dispatcher whether or not to dispatch the event.
  18 //
  19 // The nested loop is exited by either posting a quit, or returning false
  20 // from Dispatch.
  21 class BASE_EXPORT MessagePumpDispatcher {
  22  public:
  23   virtual ~MessagePumpDispatcher() {}
  24
  25   // Dispatches the event. If true is returned processing continues as
  26   // normal. If false is returned, the nested loop exits immediately.
  27   virtual bool Dispatch(const NativeEvent& event) = 0;
  28 };
  29
  30 }  // namespace base
  31
  32 #endif  // BASE_MESSAGE_PUMP_DISPATCHER_H