[gnome-shell/gbsneto/icon-grid-dnd: 93/117] folderIcon: Allow dropping application icons

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

commit e54d6350258168ca3a9568401c3b2a88990da715
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/603

 js/ui/appDisplay.js | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 94a7c7474..f62b94176 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1221,6 +1221,11 @@ 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', () => {
@@ -1254,6 +1259,47 @@ 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)