Allow layer.destroy to be called twice without failing for the vector layer. r=elemoine (closes #1697)

git-svn-id: http://svn.openlayers.org/trunk/openlayers@7941 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf

lib/OpenLayers/Layer/Vector.js

@@ -492,12 +492,12 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
      * options - {Object}
      */
     removeFeatures: function(features, options) {
+        if(!features || features.length === 0) {
+            return;
+        }
         if (!(features instanceof Array)) {
             features = [features];
         }
-        if (features.length <= 0) {
-            return;
-        }
 
         var notify = !options || !options.silent;
 
@@ -567,9 +567,11 @@ OpenLayers.Layer.Vector = OpenLayers.Class(OpenLayers.Layer, {
         if(all) {
             features = this.features;
         }
-        this.removeFeatures(features, options);
-        for (var i = 0; i < features.length; i++) {
-            features[i].destroy();
+        if(features) {
+            this.removeFeatures(features, options);
+            for(var i=features.length-1; i>=0; i--) {
+                features[i].destroy();
+            }
         }
     },
 

tests/Layer/Vector.html

@@ -238,7 +238,7 @@
     }
 
     function test_Layer_Vector_destroy (t) {
-        t.plan(4);    
+        t.plan(5);    
 
         var options = {protocol: new OpenLayers.Protocol(), 
                        strategies: [new OpenLayers.Strategy(), new OpenLayers.Strategy()]}
@@ -252,6 +252,16 @@
 
         t.eq(layer.protocol, null, "layer.protocol is null after destroy");
         t.eq(layer.strategies, null, "layer.strategies is null after destroy");
+        
+        // test that we can call layer.destroy a second time without trouble
+        try {
+            layer.destroy();
+            layer.destroy();
+            t.ok(true, "layer.destroy called twice without any issues");
+        } catch(err) {
+            t.fail("calling layer.destroy twice triggers exception: " + err + " in " + err.fileName + " line " + err.lineNumber);
+        }
+        
     }
 
     function test_Layer_Vector_externalGraphic(t) {