appDisplay: Use a drag monitor to check for out-of-dialog drags

When the app folder dialog handles a drag hover, it starts a timeout
to popdown if dragging outside the "real" dialog area. However, when
dragging inside it, BaseAppView handles all drag hover events which
would disarm the popdown timeout. In cases like this, it's almost
impossible to prevent the timeout from triggering, which always pops
down the dialog.

Add a drag monitor when handling any drag hover (which only happens
when dragging outside the folder's icon grid); and eventually disarm
the popdown timeout from the monitor's motion event. Remove the drag
monitor when dragging over the folder dialog again.

https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1284

diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 44c4f3f5ff79f5716985acab777c133aeaef55e1..fdbfef6779f624ffe922a32c02b0c15a5555cb25 100644 (file)
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -2011,6 +2011,7 @@ var AppFolderDialog = GObject.registerClass({
         this._grabHelper.addActor(Main.layoutManager.overviewGroup);
         this.connect('destroy', this._onDestroy.bind(this));
 
+        this._dragMonitor = null;
         this._sourceMappedId = 0;
         this._popdownTimeoutId = 0;
         this._needsZoomAndFade = false;
@@ -2224,6 +2225,22 @@ var AppFolderDialog = GObject.registerClass({
         this._needsZoomAndFade = false;
     }
 
+    _removeDragMonitor() {
+        if (!this._dragMonitor)
+            return;
+
+        DND.removeDragMonitor(this._dragMonitor);
+        this._dragMonitor = null;
+    }
+
+    _removePopdownTimeout() {
+        if (this._popdownTimeoutId === 0)
+            return;
+
+        GLib.source_remove(this._popdownTimeoutId);
+        this._popdownTimeoutId = 0;
+    }
+
     _onDestroy() {
         if (this._isOpen) {
             this._isOpen = false;
@@ -2236,10 +2253,8 @@ var AppFolderDialog = GObject.registerClass({
             this._sourceMappedId = 0;
         }
 
-        if (this._popdownTimeoutId > 0) {
-            GLib.source_remove(this._popdownTimeoutId);
-            this._popdownTimeoutId = 0;
-        }
+        this._removePopdownTimeout();
+        this._removeDragMonitor();
     }
 
     vfunc_allocate(box) {
@@ -2306,19 +2321,41 @@ var AppFolderDialog = GObject.registerClass({
             y < childAllocation.y2;
     }
 
+    _setupDragMonitor() {
+        if (this._dragMonitor)
+            return;
+
+        this._dragMonitor = {
+            dragMotion: dragEvent => {
+                if (this._withinDialog(dragEvent.x, dragEvent.y)) {
+                    this._removePopdownTimeout();
+                    this._removeDragMonitor();
+                }
+                return DND.DragMotionResult.CONTINUE;
+            },
+        };
+        DND.addDragMonitor(this._dragMonitor);
+    }
+
+    _setupPopdownTimeout() {
+        if (this._popdownTimeoutId > 0)
+            return;
+
+        this._popdownTimeoutId =
+            GLib.timeout_add(GLib.PRIORITY_DEFAULT, POPDOWN_DIALOG_TIMEOUT, () => {
+                this._popdownTimeoutId = 0;
+                this.popdown();
+                return GLib.SOURCE_REMOVE;
+            });
+    }
+
     handleDragOver(source, actor, x, y) {
         if (this._withinDialog(x, y)) {
-            if (this._popdownTimeoutId > 0) {
-                GLib.source_remove(this._popdownTimeoutId);
-                this._popdownTimeoutId = 0;
-            }
-        } else if (this._popdownTimeoutId === 0) {
-            this._popdownTimeoutId =
-                GLib.timeout_add(GLib.PRIORITY_DEFAULT, POPDOWN_DIALOG_TIMEOUT, () => {
-                    this._popdownTimeoutId = 0;
-                    this.popdown();
-                    return GLib.SOURCE_REMOVE;
-                });
+            this._removePopdownTimeout();
+            this._removeDragMonitor();
+        } else {
+            this._setupPopdownTimeout();
+            this._setupDragMonitor();
         }
 
         return DND.DragMotionResult.NO_DROP;