[gnome-shell/gbsneto/icon-grid-dnd: 42/43] folderView: Allow moving to specific position

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

commit 717ec0f8a4667b024c8c8344cc4e905b8fb76a71
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Fri Jul 5 11:05:29 2019 -0300

    folderView: Allow moving to specific position
    
    As of now, the only way to add an app icon to a folder is
    by dragging it to the folder icon itself. Even though we
    allow opening the folder popup when hovering the icon,
    dropping an app icon there wouldn't work.
    
    Make the folder view add the app icon to it's GSettings
    key (which will trigger _redisplay() and will show the
    new icon) when dropping to a specific position.
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/603

 js/ui/appDisplay.js | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)
---
diff --git a/js/ui/appDisplay.js b/js/ui/appDisplay.js
index 79437e24a..7e9b558e5 100644
--- a/js/ui/appDisplay.js
+++ b/js/ui/appDisplay.js
@@ -1440,13 +1440,28 @@ var FolderView = class FolderView extends BaseAppView {
 
     acceptDrop(source, actor, x, y, time) {
         let [index, dragLocation] = this.canDropAt(x, y);
-        let sourceIndex = this._allItems.indexOf(source);
         let success = index != -1;
 
         source.undoScaleAndFade();
 
-        if (success)
-            this.moveItem(source, index);
+        if (success) {
+            // If we're dragging from another folder, remove from the old folder
+            if (source.view != this &&
+                (source instanceof AppIcon) &&
+                (source.view instanceof FolderView)) {
+                source.view.removeApp(source.app);
+            }
+
+            // If the new app icon is not in this folder yet, add it; otherwise,
+            // just move the icon to the new position
+            let folderApps = this._folder.get_strv('apps');
+            if (!folderApps.includes(source.id)) {
+                folderApps.splice(index, 0, source.id);
+                this._folder.set_strv('apps', folderApps);
+            } else {
+                this.moveItem(source, index);
+            }
+        }
 
         this.removeNudges();
         return success;