added wxApp::Yield()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@12095 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/app.tex

@@ -603,3 +603,29 @@ This function currently only has effect under GTK.
 
 \docparam{flag}{If TRUE, the app will use the best visual.}
 
+\membersection{wxApp::Yield}{wxappyield}
+
+\func{bool}{Yield}{\param{bool}{ onlyIfNeeded = FALSE}}
+
+Yields control to pending messages in the windowing system. This can be useful, for example, when a
+time-consuming process writes to a text window. Without an occasional
+yield, the text window will not be updated properly, and on systems with
+cooperative multitasking, such as Windows 3.1 other processes will not respond.
+
+Caution should be exercised, however, since yielding may allow the
+user to perform actions which are not compatible with the current task.
+Disabling menu items or whole menus during processing can avoid unwanted
+reentrance of code: see \helpref{::wxSafeYield}{wxsafeyield} for a better
+function.
+
+Note that Yield() will not flush the message logs. This is intentional as
+calling Yield() is usually done to quickly update the screen and popping up a
+message box dialog may be undesirable. If you do wish to flush the log
+messages immediately (otherwise it will be done during the next idle loop
+iteration), call \helpref{wxLog::FlushActive}{wxlogflushactive}.
+
+Calling Yield() recursively is normally an error and an assert failure is
+raised in debug build if such situation is detected. However if the the 
+{\it onlyIfNeeded} parameter is {\tt TRUE}, the method will just silently
+return {\tt FALSE} instead.
+

docs/latex/wx/function.tex

@@ -2143,22 +2143,10 @@ See also \helpref{wxGetResource}{wxgetresource}, \helpref{wxConfigBase}{wxconfig
 
 \func{bool}{wxYield}{\void}
 
-Yields control to pending messages in the windowing system. This can be useful, for example, when a
+Calls \helpref{wxApp::Yield}{wxappyield}.
-time-consuming process writes to a text window. Without an occasional
-yield, the text window will not be updated properly, and on systems with
-cooperative multitasking, such as Windows 3.1 other processes will not respond.
 
-Caution should be exercised, however, since yielding may allow the
+This function is kept only for backwards compatibility, please use the
-user to perform actions which are not compatible with the current task.
+wxApp method instead in any new code.
-Disabling menu items or whole menus during processing can avoid unwanted
-reentrance of code: see \helpref{::wxSafeYield}{wxsafeyield} for a better
-function.
-
-Note that wxYield will not flush the message logs. This is intentional as
-calling wxYield is usually done to quickly update the screen and popping up a
-message box dialog may be undesirable. If you do wish to flush the log
-messages immediately (otherwise it will be done during the next idle loop
-iteration), call \helpref{wxLog::FlushActive}{wxlogflushactive}.
 
 \wxheading{Include files}
 

include/wx/app.h

@@ -65,9 +65,6 @@ public:
 
     // the virtual functions which may/must be overridden in the derived class
     // -----------------------------------------------------------------------
-#ifdef __DARWIN__
-    virtual ~wxAppBase() { }
-#endif
 
         // called during the program initialization, returning FALSE from here
         // prevents the program from continuing - it's a good place to create
@@ -135,6 +132,17 @@ public:
         // process the first event in the event queue (blocks until an event
         // apperas if there are none currently)
     virtual void Dispatch() = 0;
+
+        // process all currently pending events right now
+        //
+        // it is an error to call Yield() recursively unless the value of
+        // onlyIfNeeded is TRUE
+        //
+        // WARNING: this function is dangerous as it can lead to unexpected
+        //          reentrancies (i.e. when called from an event handler it
+        //          may result in calling the same event handler again), use
+        //          with _extreme_ care or, better, don't use at all!
+    virtual bool Yield(bool onlyIfNeeded = FALSE) = 0;
 #endif // wxUSE_GUI
 
     // application info: name, description, vendor
@@ -285,6 +293,11 @@ public:
     static wxAppInitializerFunction GetInitializerFunction()
         { return m_appInitFn; }
 
+    // needed to avoid link errors
+#ifdef __DARWIN__
+    virtual ~wxAppBase() { }
+#endif
+
     // process all events in the wxPendingEvents list
     virtual void ProcessPendingEvents();
 

include/wx/gtk/app.h

@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        app.h
+// Name:        wx/gtk/app.h
 // Purpose:
 // Author:      Robert Roebling
 // Id:          $Id$
@@ -46,6 +46,7 @@ public:
     virtual bool Initialized();
     virtual bool Pending();
     virtual void Dispatch();
+    virtual bool Yield(bool onlyIfNeeded = FALSE);
 
     virtual wxIcon GetStdIcon(int which) const;
 

include/wx/gtk1/app.h

@@ -1,5 +1,5 @@
 /////////////////////////////////////////////////////////////////////////////
-// Name:        app.h
+// Name:        wx/gtk/app.h
 // Purpose:
 // Author:      Robert Roebling
 // Id:          $Id$
@@ -46,6 +46,7 @@ public:
     virtual bool Initialized();
     virtual bool Pending();
     virtual void Dispatch();
+    virtual bool Yield(bool onlyIfNeeded = FALSE);
 
     virtual wxIcon GetStdIcon(int which) const;
 

include/wx/mac/app.h

@@ -51,6 +51,7 @@ class WXDLLEXPORT wxApp: public wxAppBase
   virtual bool Initialized();
   virtual bool Pending() ;
   virtual void Dispatch() ;
+  virtual bool Yield(bool onlyIfNeeded = FALSE);
 
   virtual wxIcon GetStdIcon(int which) const;
   virtual void SetPrintMode(int mode) { m_printMode = mode; }

include/wx/motif/app.h

@@ -53,6 +53,7 @@ public:
     virtual bool Initialized();
     virtual bool Pending();
     virtual void Dispatch();
+    virtual bool Yield(bool onlyIfNeeded = FALSE);
 
     virtual bool OnInitGui();
 

include/wx/msw/app.h

@@ -41,6 +41,7 @@ public:
     virtual bool Initialized();
     virtual bool Pending();
     virtual void Dispatch();
+    virtual bool Yield(bool onlyIfNeeded = FALSE);
 
     virtual wxIcon GetStdIcon(int which) const;
 

include/wx/os2/app.h

@@ -76,6 +76,7 @@ public:
     virtual bool Initialized(void);
     virtual bool Pending(void) ;
     virtual void Dispatch(void);
+    virtual bool Yield(bool onlyIfNeeded = FALSE);
 
     virtual wxIcon GetStdIcon(int which) const;
 

include/wx/utils.h

@@ -20,7 +20,6 @@
     #pragma interface "utils.h"
 #endif
 
-#include "wx/setup.h"
 #include "wx/object.h"
 #include "wx/list.h"
 #include "wx/filefn.h"

src/common/init.cpp

@@ -76,13 +76,6 @@ void WXDLLEXPORT wxExit()
     abort();
 }
 
-// Yield to other apps/messages
-bool WXDLLEXPORT wxYield()
-{
-    // do nothing
-    return TRUE;
-}
-
 // Yield to other apps/messages
 void WXDLLEXPORT wxWakeUpIdle()
 {

src/common/utilscmn.cpp

@@ -36,6 +36,7 @@
     #include "wx/log.h"
 
     #if wxUSE_GUI
+        #include "wx/app.h"
         #include "wx/window.h"
         #include "wx/frame.h"
         #include "wx/menu.h"
@@ -1312,4 +1313,25 @@ long wxExecute(const wxString& command,
     return wxDoExecuteWithCapture(command, output, &error);
 }
 
+// ----------------------------------------------------------------------------
+// wxApp::Yield() wrappers for backwards compatibility
+// ----------------------------------------------------------------------------
+
+bool wxYield()
+{
+#if wxUSE_GUI
+    return wxTheApp && wxTheApp->Yield();
+#else
+    return FALSE;
+#endif
+}
+
+bool wxYieldIfNeeded()
+{
+#if wxUSE_GUI
+    return wxTheApp && wxTheApp->Yield(TRUE);
+#else
+    return FALSE;
+#endif
+}
 

src/gtk/app.cpp

@@ -83,10 +83,21 @@ void wxExit()
 // wxYield
 //-----------------------------------------------------------------------------
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
+    // MT-FIXME
+    static bool s_inYield = FALSE;
+
+    if ( s_inYield )
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( wxT("wxYield called recursively" ) );
+        }
+
+        return FALSE;
+    }
+
 #if wxUSE_THREADS
     if ( !wxThread::IsMain() )
     {
@@ -95,19 +106,14 @@ bool wxYield()
     }
 #endif // wxUSE_THREADS
 
-#ifdef __WXDEBUG__
+    s_inYield = TRUE;
-    if (gs_inYield)
-        wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
-
-    gs_inYield = TRUE;
 
     if (!g_isIdle)
     {
         // We need to remove idle callbacks or the loop will
         // never finish.
-        gtk_idle_remove( wxTheApp->m_idleTag );
+        gtk_idle_remove( m_idleTag );
-        wxTheApp->m_idleTag = 0;
+        m_idleTag = 0;
         g_isIdle = TRUE;
     }
 
@@ -121,29 +127,18 @@ bool wxYield()
     /* it's necessary to call ProcessIdle() to update the frames sizes which
        might have been changed (it also will update other things set from
        OnUpdateUI() which is a nice (and desired) side effect) */
-    while (wxTheApp->ProcessIdle()) { }
+    while ( ProcessIdle() )
+    {
+    }
 
     // let the logs be flashed again
     wxLog::Resume();
 
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
 
     return TRUE;
 }
 
-//-----------------------------------------------------------------------------
-// wxYieldIfNeeded
-// Like wxYield, but fails silently if the yield is recursive.
-//-----------------------------------------------------------------------------
-
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-
-    return wxYield();
-}
-
 //-----------------------------------------------------------------------------
 // wxWakeUpIdle
 //-----------------------------------------------------------------------------

src/gtk1/app.cpp

@@ -83,10 +83,21 @@ void wxExit()
 // wxYield
 //-----------------------------------------------------------------------------
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
+    // MT-FIXME
+    static bool s_inYield = FALSE;
+
+    if ( s_inYield )
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( wxT("wxYield called recursively" ) );
+        }
+
+        return FALSE;
+    }
+
 #if wxUSE_THREADS
     if ( !wxThread::IsMain() )
     {
@@ -95,19 +106,14 @@ bool wxYield()
     }
 #endif // wxUSE_THREADS
 
-#ifdef __WXDEBUG__
+    s_inYield = TRUE;
-    if (gs_inYield)
-        wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
-
-    gs_inYield = TRUE;
 
     if (!g_isIdle)
     {
         // We need to remove idle callbacks or the loop will
         // never finish.
-        gtk_idle_remove( wxTheApp->m_idleTag );
+        gtk_idle_remove( m_idleTag );
-        wxTheApp->m_idleTag = 0;
+        m_idleTag = 0;
         g_isIdle = TRUE;
     }
 
@@ -121,29 +127,18 @@ bool wxYield()
     /* it's necessary to call ProcessIdle() to update the frames sizes which
        might have been changed (it also will update other things set from
        OnUpdateUI() which is a nice (and desired) side effect) */
-    while (wxTheApp->ProcessIdle()) { }
+    while ( ProcessIdle() )
+    {
+    }
 
     // let the logs be flashed again
     wxLog::Resume();
 
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
 
     return TRUE;
 }
 
-//-----------------------------------------------------------------------------
-// wxYieldIfNeeded
-// Like wxYield, but fails silently if the yield is recursive.
-//-----------------------------------------------------------------------------
-
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-
-    return wxYield();
-}
-
 //-----------------------------------------------------------------------------
 // wxWakeUpIdle
 //-----------------------------------------------------------------------------

src/mac/app.cpp

@@ -923,16 +923,21 @@ void wxCYield()
 
 // Yield to other processes
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
-#ifdef __WXDEBUG__    
+    static bool s_inYield = FALSE;
-    if (gs_inYield)
-        wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
 
-    gs_inYield = TRUE;
+    if (s_inYield)
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( wxT("wxYield called recursively" ) );
+        }
+
+        return FALSE;
+    }
+
+    s_inYield = TRUE;
 
 #if wxUSE_THREADS
     YieldToAnyThread() ;
@@ -950,20 +955,11 @@ bool wxYield()
 
     wxMacProcessNotifierAndPendingEvents() ;
 
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
 
     return TRUE;
 }
 
-// Yield to incoming messages; but fail silently if recursion is detected.
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-        
-    return wxYield();
-}
-
 // platform specifics
 
 void wxApp::MacSuspend( bool convertClipboard )

src/mac/carbon/app.cpp

@@ -923,16 +923,21 @@ void wxCYield()
 
 // Yield to other processes
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
-#ifdef __WXDEBUG__    
+    static bool s_inYield = FALSE;
-    if (gs_inYield)
-        wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
 
-    gs_inYield = TRUE;
+    if (s_inYield)
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( wxT("wxYield called recursively" ) );
+        }
+
+        return FALSE;
+    }
+
+    s_inYield = TRUE;
 
 #if wxUSE_THREADS
     YieldToAnyThread() ;
@@ -950,20 +955,11 @@ bool wxYield()
 
     wxMacProcessNotifierAndPendingEvents() ;
 
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
 
     return TRUE;
 }
 
-// Yield to incoming messages; but fail silently if recursion is detected.
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-        
-    return wxYield();
-}
-
 // platform specifics
 
 void wxApp::MacSuspend( bool convertClipboard )

src/motif/app.cpp

@@ -737,40 +737,30 @@ void wxExit()
 
 // Yield to other processes
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
-#ifdef __WXDEBUG__    
+    bool s_inYield = FALSE;
-    if (gs_inYield)
-        wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
 
-    gs_inYield = TRUE;
+    if ( s_inYield )
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( wxT("wxYield called recursively" ) );
+        }
+
+        return FALSE;
+    }
+
+    s_inYield = TRUE;
 
     while (wxTheApp && wxTheApp->Pending())
         wxTheApp->Dispatch();
 
-    // VZ: is it the same as this (taken from old wxExecute)?
+    s_inYield = FALSE;
-#if 0
-    XtAppProcessEvent((XtAppContext) wxTheApp->GetAppContext(), XtIMAll);
-#endif
-
-    gs_inYield = FALSE;
 
     return TRUE;
 }
 
-// Yield to incoming messages; but fail silently if recursion is detected.
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-        
-    return wxYield();
-}
-
-
 // TODO use XmGetPixmap (?) to get the really standard icons!
 
 #include "wx/generic/info.xpm"

src/msw/app.cpp

@@ -1435,20 +1435,26 @@ void wxExit()
 
 // Yield to incoming messages
 
-static bool gs_inYield = FALSE;
+bool wxApp::Yield(bool onlyIfNeeded)
-
-bool wxYield()
 {
+    // MT-FIXME
+    static bool s_inYield = FALSE;
+
     // disable log flushing from here because a call to wxYield() shouldn't
     // normally result in message boxes popping up &c
     wxLog::Suspend();
 
-#ifdef __WXDEBUG__
+    if ( s_inYield )
-    if (gs_inYield)
+    {
+        if ( !onlyIfNeeded )
+        {
             wxFAIL_MSG( wxT("wxYield called recursively" ) );
-#endif
+        }
 
-    gs_inYield = TRUE;
+        return FALSE;
+    }
+
+    s_inYield = TRUE;
 
     // we don't want to process WM_QUIT from here - it should be processed in
     // the main event loop in order to stop it
@@ -1464,27 +1470,17 @@ bool wxYield()
             break;
     }
 
-    // If they are pending events, we must process them.
+    // if there are pending events, we must process them.
-    if (wxTheApp)
+    ProcessPendingEvents();
-        wxTheApp->ProcessPendingEvents();
 
     // let the logs be flashed again
     wxLog::Resume();
 
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
 
     return TRUE;
 }
 
-// Yield to incoming messages; but fail silently if recursion is detected.
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-
-    return wxYield();
-}
-
 bool wxHandleFatalExceptions(bool doit)
 {
 #if wxUSE_ON_FATAL_EXCEPTION
@@ -1493,7 +1489,7 @@ bool wxHandleFatalExceptions(bool doit)
 
     return TRUE;
 #else
-    wxFAIL_MSG(_T("set wxUSE_ON_FATAL_EXCEPTION to 1 to sue this function"));
+    wxFAIL_MSG(_T("set wxUSE_ON_FATAL_EXCEPTION to 1 to use this function"));
 
     (void)doit;
     return FALSE;

src/os2/app.cpp

@@ -1117,13 +1117,23 @@ void wxExit()
     wxApp::CleanUp();
 } // end of wxExit
 
-static bool gs_inYield = FALSE;
-
 //
 // Yield to incoming messages
 //
-bool wxYield()
+bool wxApp::Yield(bool onlyIfNeeded)
 {
+    static bool s_inYield = FALSE;
+
+    if ( s_inYield )
+    {
+        if ( !onlyIfNeeded )
+        {
+            wxFAIL_MSG( _T("wxYield() called recursively") );
+        }
+
+        return FALSE;
+    }
+
     HAB                             vHab = 0;
     QMSG                            vMsg;
 
@@ -1133,7 +1143,7 @@ bool wxYield()
     //
     wxLog::Suspend();
 
-    gs_inYield = TRUE;
+    s_inYield = TRUE;
 
     //
     // We want to go back to the main message loop
@@ -1157,19 +1167,10 @@ bool wxYield()
     // Let the logs be flashed again
     //
     wxLog::Resume();
-    gs_inYield = FALSE;
+    s_inYield = FALSE;
     return TRUE;
 } // end of wxYield
 
-// Yield to incoming messages; but fail silently if recursion is detected.
-bool wxYieldIfNeeded()
-{
-    if (gs_inYield)
-        return FALSE;
-
-    return wxYield();
-}
-
 wxIcon wxApp::GetStdIcon(
   int                               nWhich
 ) const