Working skin stuff, minus css

src/Skinner.js

@@ -0,0 +1,75 @@
+/*
+Copyright 2015 OpenMarket Ltd
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+function extractComponent(object, path) {
+    var subObject = object[path[0]]
+    if  (subObject === undefined) {
+        return undefined;
+    }
+    if (path.length == 1) {
+        return subObject;
+    } else {
+        return extractComponent(subObject, path.slice(1));
+    }
+}
+
+class Skinner {
+    constructor() {
+        this.components = null;
+    }
+
+    getComponent(name) {
+        if (this.components === null) {
+            throw new Error(
+                "Attempted to get a component before a skin has been loaded."+
+                "This is probably because either:"+
+                " a) Your app has not called sdk.loadSkin(), or"+
+                " b) A component has called getComponent at the root level"
+            );
+        }
+        var comp = extractComponent(this.components, name.split('.'));
+        if (comp) {
+            return comp;
+        }
+        throw new Error("No such component: "+name);
+    }
+
+    load(skinObject) {
+        if (this.components !== null) {
+            throw new Error(
+                "Attempted to load a skin while a skin is already loaded"+
+                "If you want to change the active skin, call resetSkin first"
+            );
+        }
+        this.components = skinObject;
+    }
+
+    reset() {
+        this.components = null;
+    }
+}
+
+// We define one Skinner globally, because the intention is
+// very much that it is a singleton. Relying on there only being one
+// copy of the module can be dicey and not work as browserify's
+// behaviour with multiple copies of files etc. is erratic at best.
+// XXX: We can still end up with the same file twice in the resulting
+// JS bundle which is nonideal.
+if (global.mxSkinner === undefined) {
+    global.mxSkinner = new Skinner();
+}
+module.exports = global.mxSkinner;
+