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 #if defined(__WXMSW__) || defined(__WXMAC__)
  70
  71 // this class can be used to implement a standard event loop logic using
  72 // Pending() and Dispatch()
  73 //
  74 // it also handles idle processing automatically
  75 class WXDLLEXPORT wxEventLoopManual : public wxEventLoopBase
  76 {
  77 public:
  78     wxEventLoopManual();
  79
  80     // enters a loop calling OnNextIteration(), Pending() and Dispatch() and
  81     // terminating when Exit() is called
  82     virtual int Run();
  83
  84     // sets the "should exit" flag and wakes up the loop so that it terminates
  85     // soon
  86     virtual void Exit(int rc);
  87
  88 protected:
  89     // implement this to wake up the loop: usually done by posting a dummy event
  90     // to it (called from Exit())
  91     virtual void WakeUp() = 0;
  92
  93     // may be overridden to perform some action at the start of each new event
  94     // loop iteration
  95     virtual void OnNextIteration() { }
  96
  97
  98     // the loop exit code
  99     int m_exitcode;
 100
 101     // should we exit the loop?
 102     bool m_shouldExit;
 103 };
 104
 105 #endif // platforms using "manual" loop
 106
 107 // we're moving away from old m_impl wxEventLoop model as otherwise the user
 108 // code doesn't have access to platform-specific wxEventLoop methods and this
 109 // can sometimes be very useful (e.g. under MSW this is necessary for
 110 // integration with MFC) but currently this is done for MSW only, other ports
 111 // should follow a.s.a.p.
 112 #if defined(__WXPALMOS__)
 113     #include "wx/palmos/evtloop.h"
 114 #elif defined(__WXMSW__)
 115     #include "wx/msw/evtloop.h"
 116 #elif defined(__WXMAC__)
 117     #include "wx/mac/evtloop.h"
 118 #else // other platform
 119
 120 class WXDLLEXPORT wxEventLoopImpl;
 121
 122 class WXDLLEXPORT wxEventLoop : public wxEventLoopBase
 123 {
 124 public:
 125     wxEventLoop() { m_impl = NULL; }
 126     virtual ~wxEventLoop();
 127
 128     virtual int Run();
 129     virtual void Exit(int rc = 0);
 130     virtual bool Pending() const;
 131     virtual bool Dispatch();
 132
 133 protected:
 134     // the pointer to the port specific implementation class
 135     wxEventLoopImpl *m_impl;
 136
 137     DECLARE_NO_COPY_CLASS(wxEventLoop)
 138 };
 139
 140 #endif // platforms
 141
 142 inline bool wxEventLoopBase::IsRunning() const { return GetActive() == this; }
 143
 144 // ----------------------------------------------------------------------------
 145 // wxModalEventLoop
 146 // ----------------------------------------------------------------------------
 147
 148 // this is a naive generic implementation which uses wxWindowDisabler to
 149 // implement modality, we will surely need platform-specific implementations
 150 // too, this generic implementation is here only temporarily to see how it
 151 // works
 152 class WXDLLEXPORT wxModalEventLoop : public wxEventLoop
 153 {
 154 public:
 155     wxModalEventLoop(wxWindow *winModal)
 156     {
 157         m_windowDisabler = new wxWindowDisabler(winModal);
 158     }
 159
 160 protected:
 161     virtual void OnExit()
 162     {
 163         delete m_windowDisabler;
 164         m_windowDisabler = NULL;
 165
 166         wxEventLoop::OnExit();
 167     }
 168
 169 private:
 170     wxWindowDisabler *m_windowDisabler;
 171 };
 172
 173 // ----------------------------------------------------------------------------
 174 // wxEventLoopActivator: helper class for wxEventLoop implementations
 175 // ----------------------------------------------------------------------------
 176
 177 // this object sets the wxEventLoop given to the ctor as the currently active
 178 // one and unsets it in its dtor, this is especially useful in presence of
 179 // exceptions but is more tidy even when we don't use them
 180 class wxEventLoopActivator
 181 {
 182 public:
 183     wxEventLoopActivator(wxEventLoop *evtLoop)
 184     {
 185         m_evtLoopOld = wxEventLoop::GetActive();
 186         wxEventLoop::SetActive(evtLoop);
 187     }
 188
 189     ~wxEventLoopActivator()
 190     {
 191         // restore the previously active event loop
 192         wxEventLoop::SetActive(m_evtLoopOld);
 193     }
 194
 195 private:
 196     wxEventLoop *m_evtLoopOld;
 197 };
 198
 199 #endif // _WX_EVTLOOP_H_