Allow VectorSource to load and parse data

This adds url, data and parser options to the source, and makes
EPSG:4326 the default projection. It also adds a prepareFeatures
method, which is used to load/parse data once the target
projection is known.

src/ol/source/vectorsource.js

@@ -1,5 +1,8 @@
 goog.provide('ol.source.Vector');
 
+goog.require('goog.asserts');
+goog.require('goog.net.XhrIo');
+goog.require('ol.proj');
 goog.require('ol.source.Source');
 
 
@@ -7,9 +10,88 @@ goog.require('ol.source.Source');
 /**
  * @constructor
  * @extends {ol.source.Source}
- * @param {ol.source.SourceOptions} options Source options.
+ * @param {ol.source.VectorOptions} options Vector source options.
  */
 ol.source.Vector = function(options) {
-  goog.base(this, options);
+
+  /**
+   * @private
+   * @type {Object|string}
+   */
+  this.data_ = goog.isDef(options.data) ? options.data : null;
+
+  /**
+   * @private
+   * @type {ol.source.VectorLoadState}
+   */
+  this.loadState_ = ol.source.VectorLoadState.IDLE;
+
+  /**
+   * @private
+   * @type {ol.parser.Parser}
+   */
+  this.parser_ = goog.isDef(options.parser) ? options.parser : null;
+
+  /**
+   * @private
+   * @type {string|undefined}
+   */
+  this.url_ = options.url;
+
+  goog.base(this, {
+    attributions: options.attributions,
+    extent: options.extent,
+    logo: options.logo,
+    projection: goog.isDef(options.projection) ?
+        options.projection : ol.proj.get('EPSG:4326')
+  });
 };
 goog.inherits(ol.source.Vector, ol.source.Source);
+
+
+/**
+ * @param {ol.layer.Layer} layer Layer that parses the data.
+ * @param {ol.Extent} extent Extent that needs to be fetched.
+ * @param {ol.Projection} projection Projection of the view.
+ * @param {Function=} opt_callback Callback which is called when features are
+ *     parsed after loading.
+ * @return {ol.source.VectorLoadState} The current load state.
+ */
+ol.source.Vector.prototype.prepareFeatures = function(layer, extent, projection,
+    opt_callback) {
+  // TODO: Implement strategies. BBOX aware strategies will need the extent.
+  if (goog.isDef(this.url_) &&
+      this.loadState_ == ol.source.VectorLoadState.IDLE) {
+    this.loadState_ = ol.source.VectorLoadState.LOADING;
+    goog.net.XhrIo.send(this.url_, goog.bind(function(event) {
+      var xhr = event.target;
+      if (xhr.isSuccess()) {
+        // TODO: Get source projection from data if supported by parser.
+        layer.parseFeatures(xhr.getResponseText(), this.parser_, projection);
+        this.loadState_ = ol.source.VectorLoadState.LOADED;
+        if (goog.isDef(opt_callback)) {
+          opt_callback();
+        }
+      } else {
+        // TODO: Error handling.
+        this.loadState_ = ol.source.VectorLoadState.ERROR;
+      }
+    }, this));
+  } else if (!goog.isNull(this.data_)) {
+    layer.parseFeatures(this.data_, this.parser_, projection);
+    this.data_ = null;
+    this.loadState_ = ol.source.VectorLoadState.LOADED;
+  }
+  return this.loadState_;
+};
+
+
+/**
+ * @enum {number}
+ */
+ol.source.VectorLoadState = {
+  IDLE: 0,
+  LOADING: 1,
+  LOADED: 2,
+  ERROR: 3
+};