Tests for UTFGrid tiles.

lib/OpenLayers/Tile/UTFGrid.js

@@ -62,7 +62,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
 
     /** 
      * APIMethod: destroy
-     * nullify references to prevent circular references and memory leaks
+     * Clean up.
      */
     destroy: function() {
         this.clear();
@@ -82,6 +82,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
         var drawn = OpenLayers.Tile.prototype.draw.apply(this, arguments);
         if (drawn) {
             if (this.isLoading) {
+                this.abortLoading();
                 //if we're already loading, send 'reload' instead of 'loadstart'.
                 this.events.triggerEvent("reload"); 
             } else {
@@ -93,7 +94,7 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
             if (this.layer.useJSONP) {
                 // Use JSONP method to avoid xbrowser policy
                 var ols = new OpenLayers.Protocol.Script({
-                    url: this.url, 
+                    url: this.url,
                     callback: function(response) {
                         this.isLoading = false;
                         this.events.triggerEvent("loadend");
@@ -102,9 +103,10 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
                     scope: this
                 });
                 ols.read();
+                this.request = ols;
             } else {
                 // Use standard XHR
-                OpenLayers.Request.GET({
+                this.request = OpenLayers.Request.GET({
                     url: this.url,
                     callback: function(response) {
                         this.isLoading = false;
@@ -121,9 +123,21 @@ OpenLayers.Tile.UTFGrid = OpenLayers.Class(OpenLayers.Tile, {
         }
         return drawn;
     },
+    
+    /**
+     * Method: abortLoading
+     * Cancel a pending request.
+     */
+    abortLoading: function() {
+        if (this.request) {
+            this.request.abort();
+            delete this.request;
+        }
+        this.isLoading = false;
+    },
 
     /**
-     * Method: parseJSON
+     * Method: parseData
      * Parse the JSON from a request
      *
      * Parameters: