add an option to OpenLayers.Strategy.BBOX to allow not aborting previous requests

lib/OpenLayers/Strategy/BBOX.js

@@ -124,9 +124,12 @@ OpenLayers.Strategy.BBOX = OpenLayers.Class(OpenLayers.Strategy, {
      * Callback function called on "moveend" or "refresh" layer events.
      *
      * Parameters:
-     * options - {Object} An object with a property named "force", this
+     * options - {Object} Optional object whose properties will determine
-     *      property references a boolean value indicating if new data
+     *     the behaviour of this Strategy
-     *      must be incondtionally read.
+     *
+     * Valid options include:
+     * force - {Boolean} if true, new data must be unconditionally read.
+     * noAbort - {Boolean} if true, do not abort previous requests.
      */
     update: function(options) {
         var mapBounds = this.getMapBounds();
@@ -218,7 +221,7 @@ OpenLayers.Strategy.BBOX = OpenLayers.Class(OpenLayers.Strategy, {
      *      returned by the layer protocol.
      */
     triggerRead: function(options) {
-        if (this.response) {
+        if (this.response && options.noAbort !== true) {
             this.layer.protocol.abort(this.response);
             this.layer.events.triggerEvent("loadend");
         }

tests/Strategy/BBOX.html

@@ -33,7 +33,7 @@
     }
 
     function test_update(t) {
-        t.plan(5);
+        t.plan(7);
 
         // Create a dummy layer that can act as the map base layer.
         // This will be unnecessary if #1921 is addressed (allowing
@@ -43,9 +43,10 @@
         var strategy = new OpenLayers.Strategy.BBOX({
             ratio: 1 // makes for easier comparison to map bounds
         });
+        var log = [];
         var layer = new OpenLayers.Layer.Vector(null, {
             isBaseLayer: true,
-            protocol: new OpenLayers.Protocol(),
+            protocol: new OpenLayers.Protocol({abort: function(response) { log.push(response); }}),
             strategies: [strategy]
         });
 
@@ -61,6 +62,13 @@
          * should be removed when the issue(s) described in #1835 are addressed.
          */
         strategy.update({force: true});
+        strategy.response = {};
+        strategy.update({force: true});
+        t.eq(log.length, 1, "Response aborted");
+        log = [];
+        strategy.update({force: true});
+        strategy.update({force: true, noAbort: true}); 
+        t.eq(log.length, 0, "Response not aborted when noAbort is true");
 
         // test that the strategy bounds were set
         t.ok(map.getExtent().equals(strategy.bounds), "[set center] bounds set to map extent");