From 68f9d675fc6aa34d44ac2431d2f8bdd352d8e9d7 Mon Sep 17 00:00:00 2001
From: Luke Murray <Luke.Murray@serraview.com>
Date: Thu, 8 Aug 2013 17:49:24 +1000
Subject: [PATCH] fix: calling viewer.destroy() multiple times throw an error.
 And a simple destroy to mousetracker

---
 src/eventhandler.js | 22 ++++++++--------------
 src/mousetracker.js |  9 +++++++++
 src/viewer.js       | 26 ++++++++++++++++++--------
 3 files changed, 35 insertions(+), 22 deletions(-)

diff --git a/src/eventhandler.js b/src/eventhandler.js
index 430c23fc..b834b214 100644
--- a/src/eventhandler.js
+++ b/src/eventhandler.js
@@ -91,25 +91,19 @@ $.EventHandler.prototype = {
 
 
     /**
-     * Remove all event handler for a given event type.
+     * Remove all event handler for a given event type. If no type is given all event handlers for every event type is removed
      * @function
      * @param {String} eventName - Name of event for which all handlers are to be removed.
      */
     removeAllHandlers: function( eventName ) {
-        this.events[ eventName ] = [];
-    },
-
-
-    /**
-     * Remove every event handler for all event types
-     * @function
-     */
-     removeAllHandlersForAllEvents: function( ) {
-        for (var eventType in this.events) {
-            this.events[eventType] = [];
+        if (eventName){
+            this.events[ eventName ] = [];
+        } else{
+            for (var eventType in this.events) {
+                this.events[eventType] = [];
+            }
         }
-     },
-
+    },
 
     /**
      * Retrive the list of all handlers registered for a given event.
diff --git a/src/mousetracker.js b/src/mousetracker.js
index 4d81dc6b..1b4de92d 100644
--- a/src/mousetracker.js
+++ b/src/mousetracker.js
@@ -171,6 +171,15 @@
 
     $.MouseTracker.prototype = {
 
+        /**
+         * Clean up any events or objects created the mouse tracker
+         * @function
+         */
+        destroy: function() {
+            stopTracking( this );
+            this.element = null;
+        },
+
         /**
          * Are we currently tracking events on this element.
          * @deprecated Just use this.tracking
diff --git a/src/viewer.js b/src/viewer.js
index 51eaf7b3..d3dd7579 100644
--- a/src/viewer.js
+++ b/src/viewer.js
@@ -499,7 +499,9 @@ $.extend( $.Viewer.prototype, $.EventHandler.prototype, $.ControlDock.prototype,
 
         this.viewport   = this.preserveViewport ? this.viewport : null;
         //this.profiler   = null;
-        this.canvas.innerHTML = "";
+        if (this.canvas){
+            this.canvas.innerHTML = "";
+        }
 
         VIEWERS[ this.hash ] = null;
         delete VIEWERS[ this.hash ];
@@ -518,19 +520,27 @@ $.extend( $.Viewer.prototype, $.EventHandler.prototype, $.ControlDock.prototype,
     destroy: function( ) {
         this.close();
 
-        this.removeAllHandlersForAllEvents();
+        this.removeAllHandlers();
 
         // Go through top element (passed to us) and remove all children
         // Use removeChild to make sure it handles SVG or any non-html
         // also it performs better - http://jsperf.com/innerhtml-vs-removechild/15
-        while (this.element.firstChild) {
-            this.element.removeChild(this.element.firstChild);
+        if (this.element){
+            while (this.element.firstChild) {
+                this.element.removeChild(this.element.firstChild);
+            }
         }
 
-        // remove the mouse trackers - should we be cleaning up their callbacks?
-        delete this.keyboardCommandArea.innerTracker;
-        delete this.innerTracker;
-        delete this.outerTracker;
+        // destroy the mouse trackers
+        if (this.keyboardCommandArea){
+            this.keyboardCommandArea.innerTracker.destroy();
+        }
+        if (this.innerTracker){
+            this.innerTracker.destroy();
+        }
+        if (this.outerTracker){
+            this.outerTracker.destroy();
+        }
 
         // clear all our references to dom objects
         this.canvas = null;