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 // wxEventLoopBase: interface for wxEventLoop
  21 // ----------------------------------------------------------------------------
  22
  23 class WXDLLIMPEXP_BASE wxEventLoopBase
  24 {
  25 public:
  26     // trivial, but needed (because of wxEventLoopBase) ctor
  27     wxEventLoopBase() { }
  28
  29     // dtor
  30     virtual ~wxEventLoopBase() { }
  31
  32     // use this to check whether the event loop was successfully created before
  33     // using it
  34     virtual bool IsOk() const { return true; }
  35
  36     // start the event loop, return the exit code when it is finished
  37     virtual int Run() = 0;
  38
  39     // exit from the loop with the given exit code
  40     virtual void Exit(int rc = 0) = 0;
  41
  42     // return true if any events are available
  43     virtual bool Pending() const = 0;
  44
  45     // dispatch a single event, return false if we should exit from the loop
  46     virtual bool Dispatch() = 0;
  47
  48     // return currently active (running) event loop, may be NULL
  49     static wxEventLoop *GetActive() { return ms_activeLoop; }
  50
  51     // set currently active (running) event loop
  52     static void SetActive(wxEventLoop* loop) { ms_activeLoop = loop; }
  53
  54     // is this event loop running now?
  55     //
  56     // notice that even if this event loop hasn't terminated yet but has just
  57     // spawned a nested (e.g. modal) event loop, this would return false
  58     bool IsRunning() const;
  59
  60     // implement this to wake up the loop: usually done by posting a dummy event
  61     // to it (can be called from non main thread)
  62     virtual void WakeUp() = 0;
  63
  64 protected:
  65     // this function should be called before the event loop terminates, whether
  66     // this happens normally (because of Exit() call) or abnormally (because of
  67     // an exception thrown from inside the loop)
  68     virtual void OnExit() { }
  69
  70
  71     // the pointer to currently active loop
  72     static wxEventLoop *ms_activeLoop;
  73
  74     DECLARE_NO_COPY_CLASS(wxEventLoopBase)
  75 };
  76
  77 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || defined(__UNIX__)
  78
  79 // this class can be used to implement a standard event loop logic using
  80 // Pending() and Dispatch()
  81 //
  82 // it also handles idle processing automatically
  83 class WXDLLIMPEXP_BASE wxEventLoopManual : public wxEventLoopBase
  84 {
  85 public:
  86     wxEventLoopManual();
  87
  88     // enters a loop calling OnNextIteration(), Pending() and Dispatch() and
  89     // terminating when Exit() is called
  90     virtual int Run();
  91
  92     // sets the "should exit" flag and wakes up the loop so that it terminates
  93     // soon
  94     virtual void Exit(int rc = 0);
  95
  96 protected:
  97     // may be overridden to perform some action at the start of each new event
  98     // loop iteration
  99     virtual void OnNextIteration() { }
 100
 101
 102     // the loop exit code
 103     int m_exitcode;
 104
 105     // should we exit the loop?
 106     bool m_shouldExit;
 107 };
 108
 109 #endif // platforms using "manual" loop
 110
 111 // we're moving away from old m_impl wxEventLoop model as otherwise the user
 112 // code doesn't have access to platform-specific wxEventLoop methods and this
 113 // can sometimes be very useful (e.g. under MSW this is necessary for
 114 // integration with MFC) but currently this is done for MSW only, other ports
 115 // should follow a.s.a.p.
 116 #if defined(__WXPALMOS__)
 117     #include "wx/palmos/evtloop.h"
 118 #elif defined(__WXMSW__)
 119     #include "wx/msw/evtloop.h"
 120 #elif defined(__WXMAC__)
 121     #include "wx/mac/evtloop.h"
 122 #elif defined(__WXDFB__)
 123     #include "wx/dfb/evtloop.h"
 124 #else // other platform
 125
 126 class WXDLLEXPORT wxEventLoopImpl;
 127
 128 class WXDLLEXPORT wxGUIEventLoop : public wxEventLoopBase
 129 {
 130 public:
 131     wxGUIEventLoop() { m_impl = NULL; }
 132     virtual ~wxGUIEventLoop();
 133
 134     virtual int Run();
 135     virtual void Exit(int rc = 0);
 136     virtual bool Pending() const;
 137     virtual bool Dispatch();
 138     virtual void WakeUp() { }
 139
 140 protected:
 141     // the pointer to the port specific implementation class
 142     wxEventLoopImpl *m_impl;
 143
 144     DECLARE_NO_COPY_CLASS(wxGUIEventLoop)
 145 };
 146
 147 #endif // platforms
 148
 149 // also include the header defining wxConsoleEventLoop for Unix systems
 150 #if defined(__UNIX__)
 151     #include "wx/unix/evtloop.h"
 152 #endif
 153
 154 // cannot use typedef because wxEventLoop is forward-declared in many places
 155 #if wxUSE_GUI
 156 class wxEventLoop : public wxGUIEventLoop { };
 157 #elif defined(__WXMSW__) || defined(__UNIX__)
 158 class wxEventLoop : public wxConsoleEventLoop { };
 159 #else // we still must define it somehow for the code below...
 160 class wxEventLoop : public wxEventLoopBase { };
 161 #endif
 162
 163 inline bool wxEventLoopBase::IsRunning() const { return GetActive() == this; }
 164
 165 #if wxUSE_GUI
 166 // ----------------------------------------------------------------------------
 167 // wxModalEventLoop
 168 // ----------------------------------------------------------------------------
 169
 170 // this is a naive generic implementation which uses wxWindowDisabler to
 171 // implement modality, we will surely need platform-specific implementations
 172 // too, this generic implementation is here only temporarily to see how it
 173 // works
 174 class WXDLLEXPORT wxModalEventLoop : public wxGUIEventLoop
 175 {
 176 public:
 177     wxModalEventLoop(wxWindow *winModal)
 178     {
 179         m_windowDisabler = new wxWindowDisabler(winModal);
 180     }
 181
 182 protected:
 183     virtual void OnExit()
 184     {
 185         delete m_windowDisabler;
 186         m_windowDisabler = NULL;
 187
 188         wxGUIEventLoop::OnExit();
 189     }
 190
 191 private:
 192     wxWindowDisabler *m_windowDisabler;
 193 };
 194
 195 #endif //wxUSE_GUI
 196
 197 // ----------------------------------------------------------------------------
 198 // wxEventLoopActivator: helper class for wxEventLoop implementations
 199 // ----------------------------------------------------------------------------
 200
 201 // this object sets the wxEventLoop given to the ctor as the currently active
 202 // one and unsets it in its dtor, this is especially useful in presence of
 203 // exceptions but is more tidy even when we don't use them
 204 class wxEventLoopActivator
 205 {
 206 public:
 207     wxEventLoopActivator(wxEventLoopBase *evtLoop)
 208     {
 209         m_evtLoopOld = wxEventLoopBase::GetActive();
 210         wxEventLoopBase::SetActive(wx_static_cast(wxEventLoop *, evtLoop));
 211     }
 212
 213     ~wxEventLoopActivator()
 214     {
 215         // restore the previously active event loop
 216         wxEventLoopBase::SetActive(m_evtLoopOld);
 217     }
 218
 219 private:
 220     wxEventLoop *m_evtLoopOld;
 221 };
 222
 223 #endif // _WX_EVTLOOP_H_