include/wx/unix/private/wakeuppipe.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/unix/private/wakeuppipe.h
   3 // Purpose:     Helper class allowing to wake up the main thread.
   4 // Author:      Vadim Zeitlin
   5 // Created:     2013-06-09 (extracted from src/unix/evtloopunix.cpp)
   6 // RCS-ID:      $Id$
   7 // Copyright:   (c) 2013 Vadim Zeitlin <vadim@wxwidgets.org>
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 #ifndef _WX_UNIX_PRIVATE_WAKEUPPIPE_H_
  12 #define _WX_UNIX_PRIVATE_WAKEUPPIPE_H_
  13
  14 #include "wx/private/fdiohandler.h"
  15
  16 #include "wx/unix/pipe.h"
  17
  18 // ----------------------------------------------------------------------------
  19 // wxWakeUpPipe: allows to wake up the event loop by writing to it
  20 // ----------------------------------------------------------------------------
  21
  22 class wxWakeUpPipe : public wxFDIOHandler
  23 {
  24 public:
  25     // Create and initialize the pipe.
  26     //
  27     // It's the callers responsibility to add the read end of this pipe,
  28     // returned by GetReadFd(), to the code blocking on input.
  29     wxWakeUpPipe();
  30
  31     // Wake up the blocking operation involving this pipe.
  32     //
  33     // It simply writes to the write end of the pipe.
  34     //
  35     // Notice that this method can be, and often is, called from another
  36     // thread.
  37     void WakeUp();
  38
  39     // Return the read end of the pipe.
  40     int GetReadFd() { return m_pipe[wxPipe::Read]; }
  41
  42
  43     // implement wxFDIOHandler pure virtual methods
  44     virtual void OnReadWaiting();
  45     virtual void OnWriteWaiting() { }
  46     virtual void OnExceptionWaiting() { }
  47
  48 private:
  49     wxPipe m_pipe;
  50
  51     // Protects access to m_pipeIsEmpty.
  52     wxCriticalSection m_pipeLock;
  53
  54     // This flag is set to true after writing to the pipe and reset to false
  55     // after reading from it in the main thread. Having it allows us to avoid
  56     // overflowing the pipe with too many writes if the main thread can't keep
  57     // up with reading from it.
  58     bool m_pipeIsEmpty;
  59 };
  60
  61 #endif // _WX_UNIX_PRIVATE_WAKEUPPIPE_H_