From 82dc4baff620d98c4ecb21e4dcd002a65e629046 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Thu, 7 Nov 2013 12:38:44 +0100
Subject: [PATCH] Add scope and type checking to ol.reader.GeoJSON

---
 src/ol/reader/geojson/geojson.js | 51 +++++++++++++++++++-------------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/src/ol/reader/geojson/geojson.js b/src/ol/reader/geojson/geojson.js
index 26b8bf20a8..0bfe22a3ad 100644
--- a/src/ol/reader/geojson/geojson.js
+++ b/src/ol/reader/geojson/geojson.js
@@ -54,13 +54,16 @@ ol.reader.GeoJSON.readPolygonGeometry_ = function(geometry) {
 
 
 /**
- * @param {GeoJSONFeature} feature Feature.
- * @param {function(ol.Feature): *} callback Callback.
+ * @param {GeoJSONObject} object Object.
+ * @param {function(this: S, ol.Feature): T} callback Callback.
+ * @param {S=} opt_obj Scope.
  * @private
- * @return {*} Callback result.
+ * @return {T} Callback result.
+ * @template S,T
  */
-ol.reader.GeoJSON.readFeature_ = function(feature, callback) {
-  goog.asserts.assert(feature.type == 'Feature');
+ol.reader.GeoJSON.readFeature_ = function(object, callback, opt_obj) {
+  goog.asserts.assert(object.type == 'Feature');
+  var feature = /** @type {GeoJSONFeature} */ (object);
   var geometryReader =
       ol.reader.GeoJSON.GEOMETRY_READERS_[feature.geometry.type];
   goog.asserts.assert(goog.isDef(geometryReader));
@@ -69,23 +72,25 @@ ol.reader.GeoJSON.readFeature_ = function(feature, callback) {
   if (goog.isDef(feature.properties)) {
     f.setValues(feature.properties);
   }
-  return callback(f);
+  return callback.call(opt_obj, f);
 };
 
 
 /**
- * @param {GeoJSONFeatureCollection} featureCollection Feature collection.
- * @param {function(ol.Feature): *} callback Callback.
+ * @param {GeoJSONObject} object Object.
+ * @param {function(this: S, ol.Feature): T} callback Callback.
+ * @param {S=} opt_obj Scope.
  * @private
- * @return {*} Callback result.
+ * @return {T|undefined} Callback result.
+ * @template S,T
  */
-ol.reader.GeoJSON.readFeatureCollection_ =
-    function(featureCollection, callback) {
-  goog.asserts.assert(featureCollection.type == 'FeatureCollection');
+ol.reader.GeoJSON.readFeatureCollection_ = function(object, callback, opt_obj) {
+  goog.asserts.assert(object.type == 'FeatureCollection');
+  var featureCollection = /** @type {GeoJSONFeatureCollection} */ (object);
   var features = featureCollection.features;
   var i, ii;
   for (i = 0, ii = features.length; i < ii; ++i) {
-    var result = ol.reader.GeoJSON.readFeature_(features[i], callback);
+    var result = ol.reader.GeoJSON.readFeature_(features[i], callback, opt_obj);
     if (result) {
       return result;
     }
@@ -96,22 +101,26 @@ ol.reader.GeoJSON.readFeatureCollection_ =
 
 /**
  * @param {GeoJSONObject} object Object.
- * @param {function(ol.Feature): *} callback Callback.
- * @return {*} Callback result.
+ * @param {function(this: S, ol.Feature): T} callback Callback.
+ * @param {S=} opt_obj Scope.
+ * @return {T} Callback result.
+ * @template S,T
  */
-ol.reader.GeoJSON.readObject = function(object, callback) {
+ol.reader.GeoJSON.readObject = function(object, callback, opt_obj) {
   var objectReader = ol.reader.GeoJSON.OBJECT_READERS_[object.type];
   goog.asserts.assert(goog.isDef(objectReader));
-  return objectReader(object, callback);
+  return objectReader(object, callback, opt_obj);
 };
 
 
 /**
  * @param {string} string String.
- * @param {function(ol.Feature): *} callback Callback.
- * @return {*} Callback result.
+ * @param {function(ol.Feature): T} callback Callback.
+ * @param {S=} opt_obj Scope.
+ * @return {T} Callback result.
+ * @template S,T
  */
-ol.reader.GeoJSON.readString = function(string, callback) {
+ol.reader.GeoJSON.readString = function(string, callback, opt_obj) {
   var object = goog.json.parse(string);
   return ol.reader.GeoJSON.readObject(
       /** @type {GeoJSONObject} */ (object), callback);
@@ -133,7 +142,7 @@ ol.reader.GeoJSON.GEOMETRY_READERS_ = {
 /**
  * @const
  * @private
- * @type {Object.<string, function(*, function(ol.Feature): *): *>}
+ * @type {Object.<string, function(GeoJSONObject, function(ol.Feature): *, *): *>}
  */
 ol.reader.GeoJSON.OBJECT_READERS_ = {
   'Feature': ol.reader.GeoJSON.readFeature_,