From b54342dfb8df575d061a36c61bc3b43b20058db7 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Sun, 4 Dec 2016 10:24:43 -0800
Subject: [PATCH] Dedicated module for projections cache

---
 src/ol/proj/index.js       | 25 +++++++++----------------
 src/ol/proj/projections.js | 38 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+), 16 deletions(-)
 create mode 100644 src/ol/proj/projections.js

diff --git a/src/ol/proj/index.js b/src/ol/proj/index.js
index 44bd2880b1..de331c75b7 100644
--- a/src/ol/proj/index.js
+++ b/src/ol/proj/index.js
@@ -5,6 +5,7 @@ goog.provide('ol.proj.Projection');
 goog.require('ol');
 goog.require('ol.extent');
 goog.require('ol.proj.Units');
+goog.require('ol.proj.projections');
 goog.require('ol.proj.transforms');
 goog.require('ol.sphere.NORMAL');
 
@@ -23,13 +24,6 @@ ol.proj.METERS_PER_UNIT[ol.proj.Units.METERS] = 1;
 ol.proj.METERS_PER_UNIT[ol.proj.Units.USFEET] = 1200 / 3937;
 
 
-/**
- * @private
- * @type {Object.<string, ol.proj.Projection>}
- */
-ol.proj.projections_ = {};
-
-
 /**
  * @private
  * @type {proj4}
@@ -153,13 +147,12 @@ ol.proj.Projection = function(options) {
    */
   this.metersPerUnit_ = options.metersPerUnit;
 
-  var projections = ol.proj.projections_;
   var code = options.code;
   ol.DEBUG && console.assert(code !== undefined,
       'Option "code" is required for constructing instance');
   if (ol.ENABLE_PROJ4JS) {
     var proj4js = ol.proj.proj4_ || window['proj4'];
-    if (typeof proj4js == 'function' && projections[code] === undefined) {
+    if (typeof proj4js == 'function' && !ol.proj.projections.get(code)) {
       var def = proj4js.defs(code);
       if (def !== undefined) {
         if (def.axis !== undefined && options.axisOrientation === undefined) {
@@ -436,7 +429,7 @@ ol.proj.addEquivalentTransforms = function(projections1, projections2, forwardTr
  * @api stable
  */
 ol.proj.addProjection = function(projection) {
-  ol.proj.projections_[projection.getCode()] = projection;
+  ol.proj.projections.add(projection.getCode(), projection);
   ol.proj.transforms.add(projection, projection, ol.proj.cloneTransform);
 };
 
@@ -453,10 +446,10 @@ ol.proj.addProjections = function(projections) {
 
 
 /**
- * FIXME empty description for jsdoc
+ * Clear all cached projections and transforms.
  */
 ol.proj.clearAllProjections = function() {
-  ol.proj.projections_ = {};
+  ol.proj.projections.clear();
   ol.proj.transforms.clear();
 };
 
@@ -579,22 +572,22 @@ ol.proj.toLonLat = function(coordinate, opt_projection) {
  * @api stable
  */
 ol.proj.get = function(projectionLike) {
-  var projection;
+  var projection = null;
   if (projectionLike instanceof ol.proj.Projection) {
     projection = projectionLike;
   } else if (typeof projectionLike === 'string') {
     var code = projectionLike;
-    projection = ol.proj.projections_[code];
+    projection = ol.proj.projections.get(code);
     if (ol.ENABLE_PROJ4JS) {
       var proj4js = ol.proj.proj4_ || window['proj4'];
-      if (projection === undefined && typeof proj4js == 'function' &&
+      if (!projection && typeof proj4js == 'function' &&
           proj4js.defs(code) !== undefined) {
         projection = new ol.proj.Projection({code: code});
         ol.proj.addProjection(projection);
       }
     }
   }
-  return projection || null;
+  return projection;
 };
 
 
diff --git a/src/ol/proj/projections.js b/src/ol/proj/projections.js
new file mode 100644
index 0000000000..a81092a5e2
--- /dev/null
+++ b/src/ol/proj/projections.js
@@ -0,0 +1,38 @@
+goog.provide('ol.proj.projections');
+
+
+/**
+ * @private
+ * @type {Object.<string, ol.proj.Projection>}
+ */
+ol.proj.projections.cache_ = {};
+
+
+/**
+ * Clear the projections cache.
+ */
+ol.proj.projections.clear = function() {
+  ol.proj.projections.cache_ = {};
+};
+
+
+/**
+ * Get a cached projection by code.
+ * @param {string} code The code for the projection.
+ * @return {ol.proj.Projection} The projection (if cached).
+ */
+ol.proj.projections.get = function(code) {
+  var projections = ol.proj.projections.cache_;
+  return projections[code] || null;
+};
+
+
+/**
+ * Add a projection to the cache.
+ * @param {string} code The projection code.
+ * @param {ol.proj.Projection} projection The projection to cache.
+ */
+ol.proj.projections.add = function(code, projection) {
+  var projections = ol.proj.projections.cache_;
+  projections[code] = projection;
+};