preliminary documentation of wxEventLoop

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@56815 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

interface/wx/apptrait.h

@@ -40,6 +40,17 @@ public:
     */
     virtual wxConfigBase* CreateConfig();
 
+    /**
+        Used by wxWidgets to create the main event loop used by wxApp::OnRun().
+
+        The default implementation of this method in wxGUIAppTraits returns the
+        usual platform-specific GUI event loop. The version in wxConsoleAppTraits
+        returns a console-specific event loop which can be used to handle timer
+        and socket events in console programs under Unix and MSW or @NULL under
+        the other platforms where console event loops are not supported yet.
+     */
+    virtual wxEventLoopBase *CreateEventLoop() = 0;
+
     /**
         Creates the global font mapper object used for encodings/charset mapping.
     */

interface/wx/evtloop.h

@@ -0,0 +1,150 @@
+/////////////////////////////////////////////////////////////////////////////
+// Name:        wx/evtloop.h
+// Purpose:     wxEventLoop and related classes
+// Author:      Vadim Zeitlin
+// Copyright:   (C) 2008 Vadim Zeitlin
+// RCS-ID:      $Id$
+// Licence:     wxWindows license
+/////////////////////////////////////////////////////////////////////////////
+
+/**
+    @class wxEventLoopBase
+
+    Base class for all event loop implementations.
+
+    An object of this class is created by wxAppTraits::CreateEventLoop() and
+    used by wxApp to run the main application event loop.
+
+    @library{wxbase}
+    @category{appmanagement}
+
+    @see wxApp
+*/
+class wxEventLoopBase
+{
+public:
+    /**
+        Return the currently active (running) event loop.
+
+        May return @NULL if there is no active event loop (e.g. during
+        application startup or shutdown).
+     */
+    static wxEventLoopBase *GetActive();
+
+    /**
+        Set currently active (running) event loop.
+
+        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.
+     */
+    static void SetActive(wxEventLoopBase* loop);
+
+
+    /**
+        Use this to check whether the event loop was successfully created
+        before using it
+     */
+    virtual bool IsOk() const;
+
+    /**
+        Start the event loop, return the exit code when it is finished.
+
+        Logically, this method calls Dispatch() in a loop until it returns
+        @false and also takes care of generating idle events during each loop
+        iteration. However not all implementations of this class really
+        implement it like this (e.g. wxGTK does not) so you shouldn't rely on
+        Dispatch() being called from inside this function.
+
+        @return The argument passed to Exit() which terminated this event loop.
+     */
+    virtual int Run() = 0;
+
+    /**
+        Exit from the loop with the given exit code.
+     */
+    virtual void Exit(int rc = 0) = 0;
+
+    /**
+        Return true if any events are available.
+
+        If this method returns @true, calling Dispatch() will not block.
+     */
+    virtual bool Pending() const = 0;
+
+    /**
+        Dispatch a single event.
+
+        If there are currently no events in the queue, blocks until an event
+        becomes available.
+
+        @return @false only if the event loop should terminate.
+     */
+    virtual bool Dispatch() = 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;
+
+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.
+     */
+    virtual void OnExit();
+};
+
+/**
+    @class wxEventLoopActivator
+
+    Makes an event loop temporarily active.
+
+    This class is used to make the event loop active during its life-time,
+    e.g.:
+    @code
+        class MyEventLoop : public wxEventLoopBase { ... };
+
+        void RunMyLoop()
+        {
+            MyEventLoop loop;
+            wxEventLoopActivator activate(&loop);
+
+            ...
+        } // the previously active event loop restored here
+    @endcode
+
+    @library{wxbase}
+    @category{appmanagement}
+
+    @see wxEventLoopBase
+*/
+class wxEventLoopActivator
+{
+public:
+    /**
+        Makes the loop passed as the parameter currently active.
+
+        This saves the current return value of wxEventLoopBase::GetActive() and
+        then calls wxEventLoopBase::SetActive() with the given @a loop.
+     */
+    wxEventLoopActivator(wxEventLoopBase *loop);
+
+    /**
+        Restores the previously active event loop stored by the constructor.
+     */
+    ~wxEventLoopActivator();
+};