[gnome-shell/wip/pressure: 9/14] grabHelper: Add mechanism to ignore the next release event

[Jasper St. Pierre <jstpierre src gnome org>]

commit acb165eb889345713ec756b6134c1c8b638d3a9f
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Wed Feb 29 19:09:31 2012 -0500

    grabHelper: Add mechanism to ignore the next release event
    
    Some child menus go away on a press, which means that we need to
    eat the next release.

 js/ui/grabHelper.js |   29 ++++++++++++++++++++++++++---
 1 files changed, 26 insertions(+), 3 deletions(-)
---
diff --git a/js/ui/grabHelper.js b/js/ui/grabHelper.js
index 4f680ec..9c2f368 100644
--- a/js/ui/grabHelper.js
+++ b/js/ui/grabHelper.js
@@ -48,6 +48,7 @@ const GrabHelper = new Lang.Class({
         this._eventId = 0;
         this._keyFocusNotifyId = 0;
         this._focusWindowChangedId = 0;
+        this._ignoreRelease = false;
     },
 
     // addActor:
@@ -147,6 +148,16 @@ const GrabHelper = new Lang.Class({
         this.emit('grabbed');
     },
 
+    // ignoreRelease:
+    //
+    // Make sure that the next button release event evaluated by the
+    // capture event handler returns false. This is designed for things
+    // like the ComboBoxMenu that go away on press, but need to eat
+    // the next release event.
+    ignoreRelease: function() {
+        this._ignoreRelease = true;
+    },
+
     // ungrab:
     // @newFocus: (allow-none): new focus container
     // @userAction: Whether the ungrab was the cause of a user
@@ -221,8 +232,14 @@ const GrabHelper = new Lang.Class({
 
     _onCapturedEvent: function(actor, event) {
         let type = event.type();
-        let button = (type == Clutter.EventType.BUTTON_PRESS ||
-                      type == Clutter.EventType.BUTTON_RELEASE);
+        let press = type == Clutter.EventType.BUTTON_PRESS;
+        let release = type == Clutter.EventType.BUTTON_RELEASE;
+        let button = press || release;
+
+        if (release && this._ignoreRelease) {
+            this._ignoreReleas = false;
+            return false;
+        }
 
         if (!button && !this._modal)
             return false;
@@ -230,8 +247,14 @@ const GrabHelper = new Lang.Class({
         if (this._isWithinGrabbedActor(event.get_source()))
             return false;
 
-        if (button)
+        if (button) {
+            // If we have a press event, ignore the next event,
+            // which should be a release event.
+            if (press)
+                this._ignoreRelease = true;
             this.ungrab(null, true);
+        }
+
         return this._modal;
     },