include/wx/evtloop.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/evtloop.h
   3 // Purpose:     declares wxEventLoop class
   4 // Author:      Vadim Zeitlin
   5 // Modified by:
   6 // Created:     01.06.01
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) 2001 Vadim Zeitlin <zeitlin@dptmaths.ens-cachan.fr>
   9 // Licence:     wxWindows licence
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_EVTLOOP_H_
  13 #define _WX_EVTLOOP_H_
  14
  15 #include "wx/utils.h"
  16
  17 class WXDLLEXPORT wxEventLoop;
  18
  19 // ----------------------------------------------------------------------------
  20 // wxEventLoop: a GUI event loop
  21 // ----------------------------------------------------------------------------
  22
  23 class WXDLLEXPORT wxEventLoopBase
  24 {
  25 public:
  26     // trivial, but needed (because of wxEventLoopBase) ctor
  27     wxEventLoopBase() { }
  28
  29     // dtor
  30     virtual ~wxEventLoopBase() { }
  31
  32     // start the event loop, return the exit code when it is finished
  33     virtual int Run() = 0;
  34
  35     // exit from the loop with the given exit code
  36     virtual void Exit(int rc = 0) = 0;
  37
  38     // return true if any events are available
  39     virtual bool Pending() const = 0;
  40
  41     // dispatch a single event, return false if we should exit from the loop
  42     virtual bool Dispatch() = 0;
  43
  44     // return currently active (running) event loop, may be NULL
  45     static wxEventLoop *GetActive() { return ms_activeLoop; }
  46
  47     // set currently active (running) event loop
  48     static void SetActive(wxEventLoop* loop) { ms_activeLoop = loop; }
  49
  50     // is this event loop running now?
  51     //
  52     // notice that even if this event loop hasn't terminated yet but has just
  53     // spawned a nested (e.g. modal) event loop, this would return false
  54     bool IsRunning() const;
  55
  56 protected:
  57     // this function should be called before the event loop terminates, whether
  58     // this happens normally (because of Exit() call) or abnormally (because of
  59     // an exception thrown from inside the loop)
  60     virtual void OnExit() { }
  61
  62
  63     // the pointer to currently active loop
  64     static wxEventLoop *ms_activeLoop;
  65
  66     DECLARE_NO_COPY_CLASS(wxEventLoopBase)
  67 };
  68
  69 // we're moving away from old m_impl wxEventLoop model as otherwise the user
  70 // code doesn't have access to platform-specific wxEventLoop methods and this
  71 // can sometimes be very useful (e.g. under MSW this is necessary for
  72 // integration with MFC) but currently this is done for MSW only, other ports
  73 // should follow a.s.a.p.
  74 #if defined(__WXPALMOS__)
  75     #include "wx/palmos/evtloop.h"
  76 #elif defined(__WXMSW__)
  77     #include "wx/msw/evtloop.h"
  78 #else
  79
  80 class WXDLLEXPORT wxEventLoopImpl;
  81
  82 class WXDLLEXPORT wxEventLoop : public wxEventLoopBase
  83 {
  84 public:
  85     wxEventLoop() { m_impl = NULL; }
  86     virtual ~wxEventLoop();
  87
  88     virtual int Run();
  89     virtual void Exit(int rc = 0);
  90     virtual bool Pending() const;
  91     virtual bool Dispatch();
  92
  93 protected:
  94     // the pointer to the port specific implementation class
  95     wxEventLoopImpl *m_impl;
  96
  97     DECLARE_NO_COPY_CLASS(wxEventLoop)
  98         };
  99
 100 #endif // __WXMSW__/!__WXMSW__
 101
 102 inline bool wxEventLoopBase::IsRunning() const { return GetActive() == this; }
 103
 104 // ----------------------------------------------------------------------------
 105 // wxModalEventLoop
 106 // ----------------------------------------------------------------------------
 107
 108 // this is a naive generic implementation which uses wxWindowDisabler to
 109 // implement modality, we will surely need platform-specific implementations
 110 // too, this generic implementation is here only temporarily to see how it
 111 // works
 112 class WXDLLEXPORT wxModalEventLoop : public wxEventLoop
 113 {
 114 public:
 115     wxModalEventLoop(wxWindow *winModal)
 116     {
 117         m_windowDisabler = new wxWindowDisabler(winModal);
 118     }
 119
 120 protected:
 121     virtual void OnExit()
 122     {
 123         delete m_windowDisabler;
 124         m_windowDisabler = NULL;
 125
 126         wxEventLoop::OnExit();
 127     }
 128
 129 private:
 130     wxWindowDisabler *m_windowDisabler;
 131 };
 132
 133 // ----------------------------------------------------------------------------
 134 // wxEventLoopActivator: helper class for wxEventLoop implementations
 135 // ----------------------------------------------------------------------------
 136
 137 // this object sets the wxEventLoop given to the ctor as the currently active
 138 // one and unsets it in its dtor, this is especially useful in presence of
 139 // exceptions but is more tidy even when we don't use them
 140 class wxEventLoopActivator
 141 {
 142 public:
 143     wxEventLoopActivator(wxEventLoop *evtLoop)
 144     {
 145         m_evtLoopOld = wxEventLoop::GetActive();
 146         wxEventLoop::SetActive(evtLoop);
 147     }
 148
 149     ~wxEventLoopActivator()
 150     {
 151         // restore the previously active event loop
 152         wxEventLoop::SetActive(m_evtLoopOld);
 153     }
 154
 155 private:
 156     wxEventLoop *m_evtLoopOld;
 157 };
 158
 159 #endif // _WX_EVTLOOP_H_