[gnome-shell/gbsneto/custom-icon-positions: 27/28] appDisplay: Use a drag monitor to check for out-of-dialog drags

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

commit 780f0b8d64755bdc7802efb1b61376ad5bd3a7a7
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 3cef0f1786..484b0e2be8 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -2013,6 +2013,7 @@ 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;
@@ -2226,6 +2227,22 @@ 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;
@@ -2238,10 +2255,8 @@ 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) {
@@ -2308,19 +2323,41 @@ 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;