improved wxMac event loop implementation and refactored the code to share it with wxMSW

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@36847 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/evtloopcmn.cpp

@@ -0,0 +1,147 @@
+///////////////////////////////////////////////////////////////////////////////
+// Name:        src/common/evtloopcmn.cpp
+// Purpose:     common wxEventLoop-related stuff
+// Author:      Vadim Zeitlin
+// Modified by:
+// Created:     2006-01-12
+// RCS-ID:      $Id$
+// Copyright:   (c) 2006 Vadim Zeitlin <vadim@wxwindows.org>
+// Licence:     wxWindows licence
+///////////////////////////////////////////////////////////////////////////////
+
+// ============================================================================
+// declarations
+// ============================================================================
+
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
+// for compilers that support precompilation, includes "wx.h".
+#include "wx/wxprec.h"
+
+#ifdef __BORLANDC__
+    #pragma hdrstop
+#endif
+
+#include "wx/evtloop.h"
+
+// ----------------------------------------------------------------------------
+// globals
+// ----------------------------------------------------------------------------
+
+wxEventLoop *wxEventLoopBase::ms_activeLoop = NULL;
+
+// ============================================================================
+// wxEventLoopManual implementation
+// ============================================================================
+
+wxEventLoopManual::wxEventLoopManual()
+{
+    m_exitcode = 0;
+    m_shouldExit = false;
+}
+
+int wxEventLoopManual::Run()
+{
+    // event loops are not recursive, you need to create another loop!
+    wxCHECK_MSG( !IsRunning(), -1, _T("can't reenter a message loop") );
+
+    // ProcessIdle() and Dispatch() below may throw so the code here should
+    // be exception-safe, hence we must use local objects for all actions we
+    // should undo
+    wxEventLoopActivator activate(wx_static_cast(wxEventLoop *, this));
+
+    // we must ensure that OnExit() is called even if an exception is thrown
+    // from inside Dispatch() but we must call it from Exit() in normal
+    // situations because it is supposed to be called synchronously,
+    // wxModalEventLoop depends on this (so we can't just use ON_BLOCK_EXIT or
+    // something similar here)
+#if wxUSE_EXCEPTIONS
+    for ( ;; )
+    {
+        try
+        {
+#endif // wxUSE_EXCEPTIONS
+
+            // this is the event loop itself
+            for ( ;; )
+            {
+                // give them the possibility to do whatever they want
+                OnNextIteration();
+
+                // generate and process idle events for as long as we don't
+                // have anything else to do
+                while ( !Pending() && (wxTheApp && wxTheApp->ProcessIdle()) )
+                    ;
+
+                // if the "should exit" flag is set, the loop should terminate
+                // but not before processing any remaining messages so while
+                // Pending() returns true, do process them
+                if ( m_shouldExit )
+                {
+                    while ( Pending() )
+                        Dispatch();
+
+                    break;
+                }
+
+                // a message came or no more idle processing to do, sit in
+                // Dispatch() waiting for the next message
+                if ( !Dispatch() )
+                {
+                    // we got WM_QUIT
+                    break;
+                }
+            }
+
+#if wxUSE_EXCEPTIONS
+            // exit the outer loop as well
+            break;
+        }
+        catch ( ... )
+        {
+            try
+            {
+                if ( !wxTheApp || !wxTheApp->OnExceptionInMainLoop() )
+                {
+                    OnExit();
+                    break;
+                }
+                //else: continue running the event loop
+            }
+            catch ( ... )
+            {
+                // OnException() throwed, possibly rethrowing the same
+                // exception again: very good, but we still need OnExit() to
+                // be called
+                OnExit();
+                throw;
+            }
+        }
+    }
+#endif // wxUSE_EXCEPTIONS
+
+    return m_exitcode;
+}
+
+void wxEventLoopManual::Exit(int rc)
+{
+    wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
+
+    m_exitcode = rc;
+    m_shouldExit = true;
+
+    OnExit();
+
+    // all we have to do to exit from the loop is to (maybe) wake it up so that
+    // it can notice that Exit() had been called
+    //
+    // in particular, do *not* use here calls such as PostQuitMessage() (under
+    // MSW) which terminate the current event loop here because we're not sure
+    // that it is going to be processed by the correct event loop: it would be
+    // possible that another one is started and terminated by mistake if we do
+    // this
+    WakeUp();
+}
+