[gnome-shell/gbsneto/icon-grid-part2: 2/10] folderIcon: Allow dropping application icons

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

commit 7c93fdba360121544878a6f3e59de7fa5873be3a
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri Jun 28 19:47:32 2019 -0300

    folderIcon: Allow dropping application icons
    
    Connect to the overview signals related to Drag n' Drop, and
    allow dropping application icons in it. Dropping an icon
    appends the application id to the folder's GSettings key.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/664

 js/ui/appDisplay.js | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 3c6842658..d9212127f 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1218,6 +1218,11 @@ var FolderIcon = class FolderIcon {
 
         this.view = new FolderView(this._folder, parentView);
 
+        Main.overview.connect('item-drag-begin',
+                              this._onDragBegin.bind(this));
+        Main.overview.connect('item-drag-end',
+                              this._onDragEnd.bind(this));
+
         this.actor.connect('clicked', this.open.bind(this));
         this.actor.connect('destroy', this.onDestroy.bind(this));
         this.actor.connect('notify::mapped', () => {
@@ -1251,6 +1256,47 @@ var FolderIcon = class FolderIcon {
         return this.view.getAllItems().map(item => item.id);
     }
 
+    _onDragBegin() {
+        this._parentView.inhibitEventBlocker();
+    }
+
+    _onDragEnd() {
+        this._parentView.uninhibitEventBlocker();
+    }
+
+    _canDropAt(source) {
+        if (!(source instanceof AppIcon))
+            return false;
+
+        if (!global.settings.is_writable('favorite-apps'))
+            return false;
+
+        if (this._folder.get_strv('apps').includes(source.id))
+            return false
+
+        return true;
+    }
+
+    handleDragOver(source, actor, x, y, time) {
+        if (!this._canDropAt(source))
+            return DND.DragMotionResult.NO_DROP;
+
+        return DND.DragMotionResult.MOVE_DROP;
+    }
+
+    acceptDrop(source, actor, x, y, time) {
+        if (!this._canDropAt(source))
+            return true;
+
+        let app = source.app;
+        let folderApps = this._folder.get_strv('apps');
+        folderApps.push(app.id);
+
+        this._folder.set_strv('apps', folderApps);
+
+        return true;
+    }
+
     _updateName() {
         let name = _getFolderName(this._folder);
         if (this.name == name)