[gtk/wip/chergert/gdk-macos-fixes: 3/9] macos: lookup NSEvent by translated GdkEvent

[Christian Hergert <chergert src gnome org>]

commit 59cdd7ae69776a639ef9c9f77f121513fb259328
Author: Christian Hergert <chergert redhat com>
Date:   Fri Oct 9 19:58:07 2020 -0700

    macos: lookup NSEvent by translated GdkEvent
    
    This will be needed by the quartz imcontext.

 gdk/macos/gdkmacosdisplay-private.h |  1 +
 gdk/macos/gdkmacosdisplay.c         | 64 +++++++++++++++++++++++++++++++++----
 2 files changed, 58 insertions(+), 7 deletions(-)
---
diff --git a/gdk/macos/gdkmacosdisplay-private.h b/gdk/macos/gdkmacosdisplay-private.h
index a60ab0c6ac..9f45a2e200 100644
--- a/gdk/macos/gdkmacosdisplay-private.h
+++ b/gdk/macos/gdkmacosdisplay-private.h
@@ -161,6 +161,7 @@ void             _gdk_macos_display_send_button_event              (GdkMacosDisp
 void             _gdk_macos_display_warp_pointer                   (GdkMacosDisplay *self,
                                                                     int              x,
                                                                     int              y);
+NSEvent         *_gdk_macos_display_get_nsevent                    (GdkEvent        *event);
 
 G_END_DECLS
 
diff --git a/gdk/macos/gdkmacosdisplay.c b/gdk/macos/gdkmacosdisplay.c
index 13d7dc8d1b..8f6a9eb558 100644
--- a/gdk/macos/gdkmacosdisplay.c
+++ b/gdk/macos/gdkmacosdisplay.c
@@ -74,7 +74,17 @@
 
 G_DEFINE_TYPE (GdkMacosDisplay, gdk_macos_display, GDK_TYPE_DISPLAY)
 
+#define EVENT_MAP_MAX_SIZE 10
+
+typedef struct
+{
+  GList     link;
+  GdkEvent *gdk_event;
+  NSEvent  *nsevent;
+} GdkToNSEventMap;
+
 static GSource *event_source;
+static GQueue event_map = G_QUEUE_INIT;
 
 static GdkMacosMonitor *
 get_monitor (GdkMacosDisplay *self,
@@ -387,6 +397,28 @@ gdk_macos_display_notify_startup_complete (GdkDisplay  *display,
   /* Not Supported */
 }
 
+static void
+push_nsevent (GdkEvent *gdk_event,
+              NSEvent  *nsevent)
+{
+  GdkToNSEventMap *map = g_slice_new0 (GdkToNSEventMap);
+
+  map->link.data = map;
+  map->gdk_event = gdk_event_ref (gdk_event);
+  map->nsevent = g_steal_pointer (&nsevent);
+
+  g_queue_push_tail_link (&event_map, &map->link);
+
+  if (event_map.length > EVENT_MAP_MAX_SIZE)
+    {
+      map = g_queue_pop_head_link (&event_map)->data;
+
+      gdk_event_unref (map->gdk_event);
+      [map->nsevent release];
+      g_slice_free (GdkToNSEventMap, map);
+    }
+}
+
 static void
 gdk_macos_display_queue_events (GdkDisplay *display)
 {
@@ -400,14 +432,18 @@ gdk_macos_display_queue_events (GdkDisplay *display)
       GdkEvent *event = _gdk_macos_display_translate (self, nsevent);
 
       if (event != NULL)
-        _gdk_windowing_got_event (GDK_DISPLAY (self),
-                                  _gdk_event_queue_append (GDK_DISPLAY (self), event),
-                                  event,
-                                  0);
+        {
+          push_nsevent (event, nsevent);
+          _gdk_windowing_got_event (GDK_DISPLAY (self),
+                                    _gdk_event_queue_append (GDK_DISPLAY (self), event),
+                                    event,
+                                    0);
+        }
       else
-        [NSApp sendEvent:nsevent];
-
-      [nsevent release];
+        {
+          [NSApp sendEvent:nsevent];
+          [nsevent release];
+        }
     }
 }
 
@@ -1069,3 +1105,17 @@ _gdk_macos_display_warp_pointer (GdkMacosDisplay *self,
 
   CGWarpMouseCursorPosition ((CGPoint) { x, y });
 }
+
+NSEvent *
+_gdk_macos_display_get_nsevent (GdkEvent *event)
+{
+  for (const GList *iter = event_map.head; iter; iter = iter->next)
+    {
+      const GdkToNSEventMap *map = iter->data;
+
+      if (map->gdk_event == event)
+        return map->nsevent;
+    }
+
+  return NULL;
+}