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 // ----------------------------------------------------------------------------
  18 // wxEventLoopBase: interface for wxEventLoop
  19 // ----------------------------------------------------------------------------
  20
  21 class WXDLLIMPEXP_BASE wxEventLoopBase
  22 {
  23 public:
  24     // trivial, but needed (because of wxEventLoopBase) ctor
  25     wxEventLoopBase() { }
  26
  27     // dtor
  28     virtual ~wxEventLoopBase() { }
  29
  30     // use this to check whether the event loop was successfully created before
  31     // using it
  32     virtual bool IsOk() const { return true; }
  33
  34     // start the event loop, return the exit code when it is finished
  35     virtual int Run() = 0;
  36
  37     // exit from the loop with the given exit code
  38     virtual void Exit(int rc = 0) = 0;
  39
  40     // return true if any events are available
  41     virtual bool Pending() const = 0;
  42
  43     // dispatch a single event, return false if we should exit from the loop
  44     virtual bool Dispatch() = 0;
  45
  46     // return currently active (running) event loop, may be NULL
  47     static wxEventLoopBase *GetActive() { return ms_activeLoop; }
  48
  49     // set currently active (running) event loop
  50     static void SetActive(wxEventLoopBase* loop) { ms_activeLoop = loop; }
  51
  52     // is this event loop running now?
  53     //
  54     // notice that even if this event loop hasn't terminated yet but has just
  55     // spawned a nested (e.g. modal) event loop, this would return false
  56     bool IsRunning() const;
  57
  58     // implement this to wake up the loop: usually done by posting a dummy event
  59     // to it (can be called from non main thread)
  60     virtual void WakeUp() = 0;
  61
  62 protected:
  63     // this function should be called before the event loop terminates, whether
  64     // this happens normally (because of Exit() call) or abnormally (because of
  65     // an exception thrown from inside the loop)
  66     virtual void OnExit() { }
  67
  68
  69     // the pointer to currently active loop
  70     static wxEventLoopBase *ms_activeLoop;
  71
  72     DECLARE_NO_COPY_CLASS(wxEventLoopBase)
  73 };
  74
  75 #if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || defined(__UNIX__)
  76
  77 // this class can be used to implement a standard event loop logic using
  78 // Pending() and Dispatch()
  79 //
  80 // it also handles idle processing automatically
  81 class WXDLLIMPEXP_BASE wxEventLoopManual : public wxEventLoopBase
  82 {
  83 public:
  84     wxEventLoopManual();
  85
  86     // enters a loop calling OnNextIteration(), Pending() and Dispatch() and
  87     // terminating when Exit() is called
  88     virtual int Run();
  89
  90     // sets the "should exit" flag and wakes up the loop so that it terminates
  91     // soon
  92     virtual void Exit(int rc = 0);
  93
  94 protected:
  95     // may be overridden to perform some action at the start of each new event
  96     // loop iteration
  97     virtual void OnNextIteration() { }
  98
  99
 100     // the loop exit code
 101     int m_exitcode;
 102
 103     // should we exit the loop?
 104     bool m_shouldExit;
 105 };
 106
 107 #endif // platforms using "manual" loop
 108
 109 // we're moving away from old m_impl wxEventLoop model as otherwise the user
 110 // code doesn't have access to platform-specific wxEventLoop methods and this
 111 // can sometimes be very useful (e.g. under MSW this is necessary for
 112 // integration with MFC) but currently this is done for MSW only, other ports
 113 // should follow a.s.a.p.
 114 #if defined(__WXPALMOS__)
 115     #include "wx/palmos/evtloop.h"
 116 #elif defined(__WXMSW__)
 117     #include "wx/msw/evtloop.h"
 118 #elif defined(__WXMAC__)
 119     #include "wx/osx/evtloop.h"
 120 #elif defined(__WXDFB__)
 121     #include "wx/dfb/evtloop.h"
 122 #else // other platform
 123
 124 class WXDLLIMPEXP_FWD_CORE wxEventLoopImpl;
 125
 126 class WXDLLIMPEXP_CORE wxGUIEventLoop : public wxEventLoopBase
 127 {
 128 public:
 129     wxGUIEventLoop() { m_impl = NULL; }
 130     virtual ~wxGUIEventLoop();
 131
 132     virtual int Run();
 133     virtual void Exit(int rc = 0);
 134     virtual bool Pending() const;
 135     virtual bool Dispatch();
 136     virtual void WakeUp() { }
 137
 138 protected:
 139     // the pointer to the port specific implementation class
 140     wxEventLoopImpl *m_impl;
 141
 142     DECLARE_NO_COPY_CLASS(wxGUIEventLoop)
 143 };
 144
 145 #endif // platforms
 146
 147 // also include the header defining wxConsoleEventLoop for Unix systems
 148 #if defined(__UNIX__)
 149     #include "wx/unix/evtloop.h"
 150 #endif
 151
 152 // we use a class rather than a typedef because wxEventLoop is forward-declared
 153 // in many places
 154 #if wxUSE_GUI
 155     class wxEventLoop : public wxGUIEventLoop { };
 156 #else // !GUI
 157     // we can't define wxEventLoop differently in GUI and base libraries so use
 158     // a #define to still allow writing wxEventLoop in the user code
 159     #if defined(__WXMSW__) || defined(__UNIX__)
 160         #define wxEventLoop wxConsoleEventLoop
 161     #else // we still must define it somehow for the code below...
 162         #define wxEventLoop wxEventLoopBase
 163     #endif
 164 #endif
 165
 166 inline bool wxEventLoopBase::IsRunning() const { return GetActive() == this; }
 167
 168 #if wxUSE_GUI
 169 // ----------------------------------------------------------------------------
 170 // wxModalEventLoop
 171 // ----------------------------------------------------------------------------
 172
 173 // this is a naive generic implementation which uses wxWindowDisabler to
 174 // implement modality, we will surely need platform-specific implementations
 175 // too, this generic implementation is here only temporarily to see how it
 176 // works
 177 class WXDLLIMPEXP_CORE wxModalEventLoop : public wxGUIEventLoop
 178 {
 179 public:
 180     wxModalEventLoop(wxWindow *winModal)
 181     {
 182         m_windowDisabler = new wxWindowDisabler(winModal);
 183     }
 184
 185 protected:
 186     virtual void OnExit()
 187     {
 188         delete m_windowDisabler;
 189         m_windowDisabler = NULL;
 190
 191         wxGUIEventLoop::OnExit();
 192     }
 193
 194 private:
 195     wxWindowDisabler *m_windowDisabler;
 196 };
 197
 198 #endif //wxUSE_GUI
 199
 200 // ----------------------------------------------------------------------------
 201 // wxEventLoopActivator: helper class for wxEventLoop implementations
 202 // ----------------------------------------------------------------------------
 203
 204 // this object sets the wxEventLoop given to the ctor as the currently active
 205 // one and unsets it in its dtor, this is especially useful in presence of
 206 // exceptions but is more tidy even when we don't use them
 207 class wxEventLoopActivator
 208 {
 209 public:
 210     wxEventLoopActivator(wxEventLoopBase *evtLoop)
 211     {
 212         m_evtLoopOld = wxEventLoopBase::GetActive();
 213         wxEventLoopBase::SetActive(evtLoop);
 214     }
 215
 216     ~wxEventLoopActivator()
 217     {
 218         // restore the previously active event loop
 219         wxEventLoopBase::SetActive(m_evtLoopOld);
 220     }
 221
 222 private:
 223     wxEventLoopBase *m_evtLoopOld;
 224 };
 225
 226 class wxEventLoopGuarantor
 227 {
 228 public:
 229     wxEventLoopGuarantor()
 230     {
 231         m_evtLoopNew = NULL;
 232         if (!wxEventLoop::GetActive())
 233         {
 234             m_evtLoopNew = new wxEventLoop;
 235             wxEventLoop::SetActive(m_evtLoopNew);
 236         }
 237     }
 238
 239     ~wxEventLoopGuarantor()
 240     {
 241         if (m_evtLoopNew)
 242         {
 243             wxEventLoop::SetActive(NULL);
 244             delete m_evtLoopNew;
 245         }
 246     }
 247
 248 private:
 249     wxEventLoop *m_evtLoopNew;
 250 };
 251
 252 #endif // _WX_EVTLOOP_H_