[gnome-shell/gbsneto/icon-grid-dnd: 2/13] folderIcon: Allow dropping application icons

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

commit 3af39799823179687e3b8958d1e90292200139b6
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 | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 5221444db..998a11739 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1141,6 +1141,11 @@ var FolderIcon = class FolderIcon {
 
         this.view = new FolderView();
 
+        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._ensurePopup();
             this.view.actor.vscroll.adjustment.value = 0;
@@ -1159,6 +1164,48 @@ 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;
+
+        return true;
+    }
+
+    handleDragOver(source, actor, x, y, time) {
+        if (!this._canDropAt(source))
+            return DND.DragMotionResult.NO_DROP;
+
+        let folderApps = this._folder.get_strv('apps');
+        if (folderApps.indexOf(source.app.id) > -1)
+            return DND.DragMotionResult.NO_DROP;
+
+        return DND.DragMotionResult.MOVE_DROP;
+    }
+
+    acceptDrop(source, actor, x, y, time) {
+        if (!this._canDropAt(source))
+            return false;
+
+        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)