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[wxWidgets.git] / interface / wx / evtloop.h

diff --git a/interface/wx/evtloop.h b/interface/wx/evtloop.h
index be246731b55a19210606cadd71aa6ce426d85dfd..c9c6e6cb42e54e782c57612ec5c627ad97c6983f 100644 (file)
--- a/interface/wx/evtloop.h
+++ b/interface/wx/evtloop.h
@@ -4,7 +4,7 @@
 // Author:      Vadim Zeitlin
 // Copyright:   (C) 2008 Vadim Zeitlin
 // RCS-ID:      $Id$
 // Author:      Vadim Zeitlin
 // Copyright:   (C) 2008 Vadim Zeitlin
 // RCS-ID:      $Id$

-// Licence:     wxWindows license
+// Licence:     wxWindows licence

 /////////////////////////////////////////////////////////////////////////////
 
 /**
 /////////////////////////////////////////////////////////////////////////////
 
 /**


@@ -12,13 +12,34 @@
 
     Base class for all event loop implementations.
 
 
     Base class for all event loop implementations.
 

+    An event loop is a class which queries the queue of native events sent
+    to the wxWidgets application and dispatches them to the appropriate
+    wxEvtHandlers.
+

     An object of this class is created by wxAppTraits::CreateEventLoop() and
     used by wxApp to run the main application event loop.
     An object of this class is created by wxAppTraits::CreateEventLoop() and
     used by wxApp to run the main application event loop.

+    Temporary event loops are usually created by wxDialog::ShowModal().
+
+    You can create your own event loop if you need, provided that you restore
+    the main event loop once yours is destroyed (see wxEventLoopActivator).
+
+    Notice that there can be more than one event loop at any given moment, e.g.
+    an event handler called from the main loop can show a modal dialog, which
+    starts its own loop resulting in two nested loops, with the modal dialog
+    being the active one (its IsRunning() returns @true). And a handler for a
+    button inside the modal dialog can, of course, create another modal dialog
+    with its own event loop and so on. So in general event loops form a stack
+    and only the event loop at the top of the stack is considered to be active.
+    It is also the only loop that can be directly asked to terminate by calling
+    Exit() (which is done by wxDialog::EndModal()), an outer event loop can't
+    be stopped while an inner one is still running. It is however possible to
+    ask an outer event loop to terminate as soon as all its nested loops exit
+    and the control returns back to it by using ScheduleExit().

 
     @library{wxbase}
     @category{appmanagement}
 
 
     @library{wxbase}
     @category{appmanagement}
 

-    @see wxApp
+    @see wxApp, wxEventLoopActivator

 */
 class wxEventLoopBase
 {
 */
 class wxEventLoopBase
 {


@@ -37,15 +58,21 @@ public:
         Called by wxEventLoopActivator, use an instance of this class instead
         of calling this method directly to ensure that the previously active
         event loop is restored.
         Called by wxEventLoopActivator, use an instance of this class instead
         of calling this method directly to ensure that the previously active
         event loop is restored.

+
+        Results in a call to wxAppConsole::OnEventLoopEnter.

      */
     static void SetActive(wxEventLoopBase* loop);
 
      */
     static void SetActive(wxEventLoopBase* loop);
 

+    /**
+        Returns @true if this is the main loop executed by wxApp::OnRun().
+    */
+    bool IsMain() const;
+

 
     /**
 
     /**

-        Use this to check whether the event loop was successfully created
-        before using it
-     */
-    virtual bool IsOk() const;
+        @name Dispatch and processing
+    */
+    //@{

 
     /**
         Start the event loop, return the exit code when it is finished.
 
     /**
         Start the event loop, return the exit code when it is finished.


@@ -61,9 +88,47 @@ public:
     virtual int Run() = 0;
 
     /**
     virtual int Run() = 0;
 
     /**

-        Exit from the loop with the given exit code.
+        Return true if this event loop is currently running.
+
+        Notice that even if this event loop hasn't terminated yet but has just
+        spawned a nested (e.g. modal) event loop, this method would return
+        @false.
+     */
+    bool IsRunning() const;
+
+    /**
+        Use this to check whether the event loop was successfully created
+        before using it

      */
      */

-    virtual void Exit(int rc = 0) = 0;
+    virtual bool IsOk() const;
+
+    /**
+        Exit the currently running loop with the given exit code.
+
+        The loop will exit, i.e. its Run() method will return, during the next
+        event loop iteration.
+
+        Notice that this method can only be used if this event loop is the
+        currently running one, i.e. its IsRunning() returns @true. If this is
+        not the case, an assert failure is triggered and nothing is done as
+        outer event loops can't be exited from immediately. Use ScheduleExit()
+        if you'd like to exit this loop even if it doesn't run currently.
+     */
+    virtual void Exit(int rc = 0);
+
+    /**
+        Schedule an exit from the loop with the given exit code.
+
+        This method is similar to Exit() but can be called even if this event
+        loop is not the currently running one -- and if it is the active loop,
+        then it works in exactly the same way as Exit().
+
+        The loop will exit as soon as the control flow returns to it, i.e.
+        after any nested loops terminate.
+
+        @since 2.9.5
+     */
+    virtual void ScheduleExit(int rc = 0) = 0;

 
     /**
         Return true if any events are available.
 
     /**
         Return true if any events are available.


@@ -73,13 +138,21 @@ public:
     virtual bool Pending() const = 0;
 
     /**
     virtual bool Pending() const = 0;
 
     /**

-        Dispatch a single event.
+        Dispatches the next event in the windowing system event queue.
+        Blocks until an event appears if there are none currently
+        (use Pending() if this is not wanted).

 
 

-        If there are currently no events in the queue, blocks until an event
-        becomes available.
+        This can be used for programming event loops, e.g.

 
 

-        @return @false only if the event loop should terminate.
-     */
+        @code
+        while (evtloop->Pending())
+            evtloop->Dispatch();
+        @endcode
+
+        @return @false if the event loop should stop and @true otherwise.
+
+        @see Pending(), wxEventLoopBase
+    */

     virtual bool Dispatch() = 0;
 
     /**
     virtual bool Dispatch() = 0;
 
     /**


@@ -100,28 +173,111 @@ public:
      */
     virtual int DispatchTimeout(unsigned long timeout) = 0;
 
      */
     virtual int DispatchTimeout(unsigned long timeout) = 0;
 

-    /**
-        Return true if this event loop is currently running.
-
-        Notice that even if this event loop hasn't terminated yet but has just
-        spawned a nested (e.g. modal) event loop, this method would return
-        @false.
-     */
-    bool IsRunning() const;
-

     /**
         Called by wxWidgets to wake up the event loop even if it is currently
         blocked inside Dispatch().
      */
     virtual void WakeUp() = 0;
 
     /**
         Called by wxWidgets to wake up the event loop even if it is currently
         blocked inside Dispatch().
      */
     virtual void WakeUp() = 0;
 

+    //@}
+
+
+    /**
+        @name Idle handling
+    */
+    //@{
+
+    /**
+        Makes sure that idle events are sent again.
+    */
+    virtual void WakeUpIdle();
+
+    /**
+        This virtual function is called  when the application becomes idle and
+        normally just sends wxIdleEvent to all interested parties.
+
+        It should return @true if more idle events are needed, @false if not.
+    */
+    virtual bool ProcessIdle();
+
+    //@}
+
+
+    /**
+        @name Yield-related hooks
+    */
+    //@{
+
+    /**
+        Returns @true if called from inside Yield() or from inside YieldFor().
+    */
+    virtual bool IsYielding() const;
+
+    /**
+        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 ::wxSafeYield for a better function.
+        You can avoid unwanted reentrancies also using IsYielding().
+
+        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 wxLog::FlushActive.
+
+        Calling Yield() recursively is normally an error and an assert failure is
+        raised in debug build if such situation is detected. However if the
+        @a onlyIfNeeded parameter is @true, the method will just silently
+        return @false instead.
+    */
+    bool Yield(bool onlyIfNeeded = false);
+
+    /**
+        Works like Yield() with @e onlyIfNeeded == @true, except that it allows
+        the caller to specify a mask of the ::wxEventCategory values which
+        indicates which events should be processed and which should instead
+        be "delayed" (i.e. processed by the main loop later).
+
+        Note that this is a safer alternative to Yield() since it ensures that
+        only the events you're interested to will be processed; i.e. this method
+        helps to avoid unwanted reentrancies.
+
+        Note that currently only wxMSW and wxGTK do support selective yield of
+        native events coming from the underlying GUI toolkit.
+        wxWidgets events posted using wxEvtHandler::AddPendingEvent or
+        wxEvtHandler::QueueEvent are instead selectively processed by all ports.
+
+        @see wxEvent::GetEventCategory
+    */
+    bool YieldFor(long eventsToProcess);
+
+    /**
+        Returns @true if the given event category is allowed inside
+        a YieldFor() call (i.e. compares the given category against the
+        last mask passed to YieldFor()).
+
+        @see wxEvent::GetEventCategory
+    */
+    virtual bool IsEventAllowedInsideYield(wxEventCategory cat) const;
+
+    //@}
+
+

 protected:
     /**
         This function is called before the event loop terminates, whether this
         happens normally (because of Exit() call) or abnormally (because of an
         exception thrown from inside the loop).
 
 protected:
     /**
         This function is called before the event loop terminates, whether this
         happens normally (because of Exit() call) or abnormally (because of an
         exception thrown from inside the loop).
 

-        Default version does nothing.
+        The default implementation calls wxAppConsole::OnEventLoopExit.

      */
     virtual void OnExit();
 };
      */
     virtual void OnExit();
 };


@@ -166,3 +322,20 @@ public:
      */
     ~wxEventLoopActivator();
 };
      */
     ~wxEventLoopActivator();
 };

+
+/**
+    @class wxGUIEventLoop
+
+    A generic implementation of the GUI event loop.
+    
+    @library{wxbase}
+    @category{appmanagement}
+*/
+class wxGUIEventLoop : public wxEventLoopBase
+{
+public:
+    wxGUIEventLoop();
+    virtual ~wxGUIEventLoop();
+};
+
+