[gnome-shell] layout: Fix several issues with the background management code

[Jasper St. Pierre <jstpierre src gnome org>]

commit 831bd07b0d6b7055fea8317f2cdf8fd4a408c36d
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Thu Nov 7 17:14:47 2013 -0500

    layout: Fix several issues with the background management code
    
    If monitor-changed fires at startup, it will destroy all of the
    backgrounds, but since this._isStartup is true, won't recreate any
    of them. Additionally, since _bgManagers is indexed by monitor index,
    if the primary index is not 0, it could become a sparse array (e.g.
    [undefined, undefined, primaryBackground]), and our for loop will
    crash trying to access properties of undefined.
    
    Fix both of these issues by always creating background managers for
    every monitor, hiding them on startup but only showing them after
    the startup animation is complete.
    
    One thing we need to watch out for is that while LayoutManager is
    constructing, Main.uiGroup / Main.layoutManager will be undefined,
    so addBackgroundMenu will fail. Fix this by passing down the uiGroup
    to the background menu code.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=709313

 js/ui/backgroundMenu.js |   10 +++++-----
 js/ui/layout.js         |   39 ++++++++++++++++++---------------------
 2 files changed, 23 insertions(+), 26 deletions(-)
---
diff --git a/js/ui/backgroundMenu.js b/js/ui/backgroundMenu.js
index 06e698c..dcbbb39 100644
--- a/js/ui/backgroundMenu.js
+++ b/js/ui/backgroundMenu.js
@@ -13,7 +13,7 @@ const BackgroundMenu = new Lang.Class({
     Name: 'BackgroundMenu',
     Extends: PopupMenu.PopupMenu,
 
-    _init: function(source) {
+    _init: function(source, layoutManager) {
         this.parent(source, 0, St.Side.TOP);
 
         this.addSettingsAction(_("Settings"), 'gnome-control-center.desktop');
@@ -22,17 +22,17 @@ const BackgroundMenu = new Lang.Class({
 
         this.actor.add_style_class_name('background-menu');
 
-        Main.uiGroup.add_actor(this.actor);
+        layoutManager.uiGroup.add_actor(this.actor);
         this.actor.hide();
     }
 });
 
-function addBackgroundMenu(actor) {
+function addBackgroundMenu(actor, layoutManager) {
     let cursor = new St.Bin({ opacity: 0 });
-    Main.uiGroup.add_actor(cursor);
+    layoutManager.uiGroup.add_actor(cursor);
 
     actor.reactive = true;
-    actor._backgroundMenu = new BackgroundMenu(cursor);
+    actor._backgroundMenu = new BackgroundMenu(cursor, layoutManager);
     actor._backgroundManager = new PopupMenu.PopupMenuManager({ actor: actor });
     actor._backgroundManager.addMenu(actor._backgroundMenu);
 
diff --git a/js/ui/layout.js b/js/ui/layout.js
index 17073a6..80bae9d 100644
--- a/js/ui/layout.js
+++ b/js/ui/layout.js
@@ -352,26 +352,26 @@ const LayoutManager = new Lang.Class({
         this.emit('hot-corners-changed');
     },
 
-    _createBackground: function(monitorIndex) {
+    _addBackgroundMenu: function(bgManager) {
+        BackgroundMenu.addBackgroundMenu(bgManager.background.actor, this);
+    },
+
+    _createBackgroundManager: function(monitorIndex) {
         let bgManager = new Background.BackgroundManager({ container: this._backgroundGroup,
                                                            layoutManager: this,
                                                            monitorIndex: monitorIndex });
-        BackgroundMenu.addBackgroundMenu(bgManager.background.actor);
-
-        bgManager.connect('changed', Lang.bind(this, function() {
-                              BackgroundMenu.addBackgroundMenu(bgManager.background.actor);
-                          }));
 
-        this._bgManagers[monitorIndex] = bgManager;
+        bgManager.connect('changed', Lang.bind(this, this._addBackgroundMenu));
+        this._addBackgroundMenu(bgManager);
 
-        return bgManager.background;
+        return bgManager;
     },
 
-    _createSecondaryBackgrounds: function() {
+    _showSecondaryBackgrounds: function() {
         for (let i = 0; i < this.monitors.length; i++) {
             if (i != this.primaryIndex) {
-                let background = this._createBackground(i);
-
+                let background = this._bgManagers[i].background;
+                background.actor.show();
                 background.actor.opacity = 0;
                 Tweener.addTween(background.actor,
                                  { opacity: 255,
@@ -381,10 +381,6 @@ const LayoutManager = new Lang.Class({
         }
     },
 
-    _createPrimaryBackground: function() {
-        this._createBackground(this.primaryIndex);
-    },
-
     _updateBackgrounds: function() {
         let i;
         for (i = 0; i < this._bgManagers.length; i++)
@@ -395,11 +391,12 @@ const LayoutManager = new Lang.Class({
         if (Main.sessionMode.isGreeter)
             return;
 
-        if (this._startingUp)
-            return;
-
         for (let i = 0; i < this.monitors.length; i++) {
-            this._createBackground(i);
+            let bgManager = this._createBackgroundManager(i);
+            this._bgManagers.push(bgManager);
+
+            if (i != this.primaryIndex && this._startingUp)
+                bgManager.background.actor.hide();
         }
     },
 
@@ -595,7 +592,7 @@ const LayoutManager = new Lang.Class({
         if (Main.sessionMode.isGreeter) {
             this.panelBox.translation_y = -this.panelBox.height;
         } else {
-            this._createPrimaryBackground();
+            this._updateBackgrounds();
 
             // We need to force an update of the regions now before we scale
             // the UI group to get the coorect allocation for the struts.
@@ -673,7 +670,7 @@ const LayoutManager = new Lang.Class({
         this.keyboardBox.show();
 
         if (!Main.sessionMode.isGreeter) {
-            this._createSecondaryBackgrounds();
+            this._showSecondaryBackgrounds();
             global.window_group.remove_clip();
         }