[gtk] gdk_quartz_keymap_translate_keyboard_state fills consumed_modifiers incorrectly (closes #2102)

[Alex Samorukov <asamorukov src gnome org>]

commit f0cbd175cdf1f7655c0c0ce3beb3eadc9b4c97e4
Author: Alex Samorukov <samm os2 kiev ua>
Date:   Fri Jan 10 22:18:24 2020 +0100

    gdk_quartz_keymap_translate_keyboard_state fills consumed_modifiers
    incorrectly (closes #2102)
    
    See merge request GNOME/gtk!1225

 gdk/quartz/gdkkeys-quartz.c | 28 +++++++++++++---------------
 1 file changed, 13 insertions(+), 15 deletions(-)
---
diff --git a/gdk/quartz/gdkkeys-quartz.c b/gdk/quartz/gdkkeys-quartz.c
index f9857831c9..6ded6b1a34 100644
--- a/gdk/quartz/gdkkeys-quartz.c
+++ b/gdk/quartz/gdkkeys-quartz.c
@@ -680,7 +680,6 @@ gdk_quartz_keymap_translate_keyboard_state (GdkKeymap       *keymap,
 {
   guint tmp_keyval;
   GdkModifierType bit;
-  guint tmp_modifiers = 0;
 
   if (keyval)
     *keyval = 0;
@@ -694,24 +693,23 @@ gdk_quartz_keymap_translate_keyboard_state (GdkKeymap       *keymap,
   if (hardware_keycode < 0 || hardware_keycode >= NUM_KEYCODES)
     return FALSE;
 
+  tmp_keyval = translate_keysym (hardware_keycode, group, state, level, effective_group);
+
   /* Check if modifiers modify the keyval */
-  for (bit = GDK_SHIFT_MASK; bit < GDK_BUTTON1_MASK; bit <<= 1)
+  if (consumed_modifiers)
     {
-      if (translate_keysym (hardware_keycode,
-                            (bit == GDK_MOD1_MASK) ? 0 : group,
-                            state & ~bit,
-                            NULL, NULL) !=
-         translate_keysym (hardware_keycode,
-                            (bit == GDK_MOD1_MASK) ? 1 : group,
-                            state | bit,
-                            NULL, NULL))
-       tmp_modifiers |= bit;
-    }
+      guint tmp_modifiers = (state & GDK_MODIFIER_MASK);
 
-  tmp_keyval = translate_keysym (hardware_keycode, group, state, level, effective_group);
+      for (bit = 1; bit <= tmp_modifiers; bit <<= 1)
+        {
+          if ((bit & tmp_modifiers) &&
+              translate_keysym (hardware_keycode, group, state & ~bit,
+                                NULL, NULL) == tmp_keyval)
+            tmp_modifiers &= ~bit;
+        }
 
-  if (consumed_modifiers)
-    *consumed_modifiers = tmp_modifiers;
+      *consumed_modifiers = tmp_modifiers;
+    }
 
   if (keyval)
     *keyval = tmp_keyval;