Enable use of custom XHR loader for TileVector sources

externs/olx.js

@@ -4022,10 +4022,11 @@ olx.source.TileImageOptions.prototype.wrapX;
 
 /**
  * @typedef {{attributions: (Array.<ol.Attribution>|undefined),
- *     format: ol.format.Feature,
+ *     format: (ol.format.Feature|undefined),
  *     logo: (string|olx.LogoOptions|undefined),
  *     tileGrid: ol.tilegrid.TileGrid,
  *     tileUrlFunction: (ol.TileUrlFunctionType|undefined),
+ *     tileLoadFunction: (ol.TileVectorLoadFunctionType|undefined),
  *     url: (string|undefined),
  *     urls: (Array.<string>|undefined),
  *     wrapX: (boolean|undefined)}}
@@ -4043,8 +4044,8 @@ olx.source.TileVectorOptions.prototype.attributions;
 
 
 /**
- * Format.
- * @type {ol.format.Feature}
+ * Format. Required unless tileLoadFunction is used.
+ * @type {ol.format.Feature|undefined}
  * @api
  */
 olx.source.TileVectorOptions.prototype.format;
@@ -4075,6 +4076,16 @@ olx.source.TileVectorOptions.prototype.tileGrid;
 olx.source.TileVectorOptions.prototype.tileUrlFunction;
 
 
+/**
+ * Optional function to override the default loading and format parsing behaviour.
+ * If this option is used format is ignored and the provided function will be
+ * responsible for data retrieval and transformation into features.
+ * @type {ol.TileVectorLoadFunctionType|undefined}
+ * @api
+ */
+olx.source.TileVectorOptions.prototype.tileLoadFunction;
+
+
 /**
  * URL template. Must include `{x}`, `{y}` or `{-y}`, and `{z}` placeholders.
  * @type {string|undefined}

src/ol/source/tilevectorsource.js

@@ -34,12 +34,9 @@ ol.source.TileVector = function(options) {
 
   /**
    * @private
-   * @type {ol.format.Feature}
+   * @type {ol.format.Feature|undefined}
    */
-  this.format_ = options.format;
-
-  goog.asserts.assert(goog.isDefAndNotNull(this.format_),
-      'ol.source.TileVector requires a format');
+  this.format_ = goog.isDef(options.format) ? options.format : null;
 
   /**
    * @private
@@ -53,6 +50,17 @@ ol.source.TileVector = function(options) {
    */
   this.tileUrlFunction_ = ol.TileUrlFunction.nullTileUrlFunction;
 
+  /**
+   * @private
+   * @type {?ol.TileVectorLoadFunctionType}
+   */
+  this.tileLoadFunction_ = goog.isDef(options.tileLoadFunction) ?
+      options.tileLoadFunction : null;
+
+  goog.asserts.assert(!goog.isNull(this.format_) ||
+      !goog.isNull(this.tileLoadFunction_),
+      'Either format or tileLoadFunction are required');
+
   /**
    * @private
    * @type {Object.<string, Array.<ol.Feature>>}
@@ -299,9 +307,14 @@ ol.source.TileVector.prototype.loadFeatures =
             tileUrlFunction(urlTileCoord, 1, projection);
         if (goog.isDef(url)) {
           tiles[tileKey] = [];
-          var loader = ol.featureloader.loadFeaturesXhr(url, this.format_,
-              goog.partial(success, tileKey));
-          loader.call(this, extent, resolution, projection);
+          var tileSuccess = goog.partial(success, tileKey);
+          if (!goog.isNull(this.tileLoadFunction_)) {
+            this.tileLoadFunction_(url, tileSuccess);
+          } else {
+            var loader = ol.featureloader.loadFeaturesXhr(url,
+                /** @type {ol.format.Feature} */ (this.format_), tileSuccess);
+            loader.call(this, extent, resolution, projection);
+          }
         }
       }
     }

src/ol/tileloadfunction.js

@@ -1,4 +1,5 @@
 goog.provide('ol.TileLoadFunctionType');
+goog.provide('ol.TileVectorLoadFunctionType');
 
 
 /**
@@ -9,3 +10,13 @@ goog.provide('ol.TileLoadFunctionType');
  * @api
  */
 ol.TileLoadFunctionType;
+
+
+/**
+ * A function that is called with a tile url for the features to load and
+ * a callback that takes the loaded features as argument.
+ *
+ * @typedef {function(string, function(Array.<ol.Feature>))}
+ * @api
+ */
+ol.TileVectorLoadFunctionType;