[PATCH v4 4/6] winex11: Avoid breaking XIM sequence when merging ConfigureNotify events.

[Rémi Bernon]

From: Rémi Bernon

---
 dlls/winex11.drv/event.c | 40 +++++++++++++++++++++++-----------------
 1 file changed, 23 insertions(+), 17 deletions(-)

diff --git a/dlls/winex11.drv/event.c b/dlls/winex11.drv/event.c
index bf7d503ac76..04aef2249e9 100644
--- a/dlls/winex11.drv/event.c
+++ b/dlls/winex11.drv/event.c
@@ -348,6 +348,24 @@ static enum event_merge_action merge_raw_motion_events( XIRawEvent *prev, XIRawE
 }
 #endif

+/* merge ConfigureNotify events to reduce the chances of window resize feedback loops */
+static BOOL merge_configure_events( Display *display, XEvent *prev, XEvent *next )
+{
+    BOOL queued = FALSE;
+
+    /* allow merging ConfigureNotify across Expose and PropertyNotify events */
+    if (next->type == Expose || next->type == PropertyNotify) return FALSE;
+    if (next->type != ConfigureNotify) return handle_delayed_event( display, prev );
+
+    if (!prev->type || prev->xany.window != next->xany.window) queued |= handle_delayed_event( display, prev );
+    else WARN( "discarding duplicate ConfigureNotify for window %lx\n", next->xany.window );
+
+    TRACE( "delaying ConfigureNotify for window %lx for merging\n", next->xany.window );
+    *prev = *next;
+    next->type = 0;
+    return queued;
+}
+
 /***********************************************************************
  *           merge_events
  *
@@ -357,21 +375,6 @@ static enum event_merge_action merge_events( XEvent *prev, XEvent *next )
 {
     switch (prev->type)
     {
-    case ConfigureNotify:
-        switch (next->type)
-        {
-        case ConfigureNotify:
-            if (prev->xany.window == next->xany.window)
-            {
-                TRACE( "discarding duplicate ConfigureNotify for window %lx\n", prev->xany.window );
-                return MERGE_DISCARD;
-            }
-            break;
-        case Expose:
-        case PropertyNotify:
-            return MERGE_KEEP;
-        }
-        break;
     case MotionNotify:
         switch (next->type)
         {
@@ -415,7 +418,7 @@ BOOL X11DRV_ProcessEvents( DWORD mask )
 {
     struct x11drv_thread_data *data = x11drv_thread_data();
     Display *display = data->display;
-    XEvent event, prev_event;
+    XEvent event, prev_configure = {0}, prev_event;
     int count = 0;
     BOOL queued = FALSE;
     enum event_merge_action action = MERGE_DISCARD;
@@ -458,7 +461,9 @@ BOOL X11DRV_ProcessEvents( DWORD mask )
                 continue;  /* filtered, ignore it */
         }
         get_event_data( &event );
-        if (prev_event.type) action = merge_events( &prev_event, &event );
+        queued |= merge_configure_events( display, &prev_configure, &event );
+        if (!event.type) action = MERGE_IGNORE;
+        else if (prev_event.type) action = merge_events( &prev_event, &event );
         switch( action )
         {
         case MERGE_HANDLE:  /* handle prev, keep new */
@@ -477,6 +482,7 @@ BOOL X11DRV_ProcessEvents( DWORD mask )
             break;
         }
     }
+    queued |= handle_delayed_event( display, &prev_configure );
     queued |= handle_delayed_event( display, &prev_event );
     XFlush( gdi_display );
     if (count) TRACE( "processed %d events, returning %d\n", count, queued );