[gnome-shell/gbsneto/custom-icon-positions: 18/19] appDisplay: Use a drag monitor to check for out-of-dialog drags

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit d01123768143a3c5f00a59fa8ce0b19a691f8e90
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Jun 25 16:51:30 2020 -0300

    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

 js/ui/appDisplay.js | 67 +++++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 52 insertions(+), 15 deletions(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 75a0c2f39c..847eb28c34 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -2006,6 +2006,7 @@ 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;
@@ -2219,6 +2220,22 @@ 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;
@@ -2231,10 +2248,8 @@ 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) {
@@ -2301,19 +2316,41 @@ 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;