fixing overrelease and out-of-bounds write, fixes #13725

[wxWidgets.git] / src / common / evtloopcmn.cpp

diff --git a/src/common/evtloopcmn.cpp b/src/common/evtloopcmn.cpp
index f4adbbed10bcd5218273b592f51770b0a72ddde6..99f2d78f3dda3ebdda6111a3d7a6e689104ad81f 100644 (file)
--- a/src/common/evtloopcmn.cpp
+++ b/src/common/evtloopcmn.cpp
@@ -82,7 +82,7 @@ bool wxEventLoopBase::Yield(bool onlyIfNeeded)
 }
 
 // wxEventLoopManual is unused in the other ports
-#if defined(__WXMSW__) || defined(__WXMAC__) || defined(__WXDFB__) || (defined(__UNIX__) && wxUSE_BASE)
+#if defined(__WINDOWS__) || defined(__WXDFB__) || ( ( defined(__UNIX__) && !defined(__WXOSX__) ) && wxUSE_BASE)
 
 // ============================================================================
 // wxEventLoopManual implementation
@@ -94,18 +94,41 @@ wxEventLoopManual::wxEventLoopManual()
     m_shouldExit = false;
 }
 
+bool wxEventLoopManual::ProcessEvents()
+{
+    // process pending wx events first as they correspond to low-level events
+    // which happened before, i.e. typically pending events were queued by a
+    // previous call to Dispatch() and if we didn't process them now the next
+    // call to it might enqueue them again (as happens with e.g. socket events
+    // which would be generated as long as there is input available on socket
+    // and this input is only removed from it when pending event handlers are
+    // executed)
+    if ( wxTheApp )
+    {
+        wxTheApp->ProcessPendingEvents();
+
+        // One of the pending event handlers could have decided to exit the
+        // loop so check for the flag before trying to dispatch more events
+        // (which could block indefinitely if no more are coming).
+        if ( m_shouldExit )
+            return false;
+    }
+
+    return Dispatch();
+}
+
 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") );
+    wxCHECK_MSG( !IsRunning(), -1, wxT("can't reenter a message loop") );
 
-    // ProcessIdle() and Dispatch() below may throw so the code here should
+    // ProcessIdle() and ProcessEvents() 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(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
+    // from inside ProcessEvents() 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)
@@ -124,29 +147,49 @@ int wxEventLoopManual::Run()
 
                 // generate and process idle events for as long as we don't
                 // have anything else to do
-                while ( !Pending() && ProcessIdle() )
+                while ( !m_shouldExit && !Pending() && 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() )
+                // a message came or no more idle processing to do, dispatch
+                // all the pending events and call Dispatch() to wait for the
+                // next message
+                if ( !ProcessEvents() )
                 {
                     // we got WM_QUIT
                     break;
                 }
             }
 
+            // Process the remaining queued messages, both at the level of the
+            // underlying toolkit level (Pending/Dispatch()) and wx level
+            // (Has/ProcessPendingEvents()).
+            //
+            // We do run the risk of never exiting this loop if pending event
+            // handlers endlessly generate new events but they shouldn't do
+            // this in a well-behaved program and we shouldn't just discard the
+            // events we already have, they might be important.
+            for ( ;; )
+            {
+                bool hasMoreEvents = false;
+                if ( wxTheApp && wxTheApp->HasPendingEvents() )
+                {
+                    wxTheApp->ProcessPendingEvents();
+                    hasMoreEvents = true;
+                }
+
+                if ( Pending() )
+                {
+                    Dispatch();
+                    hasMoreEvents = true;
+                }
+
+                if ( !hasMoreEvents )
+                    break;
+            }
+
 #if wxUSE_EXCEPTIONS
             // exit the outer loop as well
             break;
@@ -179,7 +222,7 @@ int wxEventLoopManual::Run()
 
 void wxEventLoopManual::Exit(int rc)
 {
-    wxCHECK_RET( IsRunning(), _T("can't call Exit() if not running") );
+    wxCHECK_RET( IsRunning(), wxT("can't call Exit() if not running") );
 
     m_exitcode = rc;
     m_shouldExit = true;
@@ -197,5 +240,5 @@ void wxEventLoopManual::Exit(int rc)
     WakeUp();
 }
 
-#endif // __WXMSW__ || __WXMAC__ || __WXDFB__
+#endif // __WINDOWS__ || __WXMAC__ || __WXDFB__