ENH: refs #0377. Add javascript callback framework just like our php one

Author: zachmullen

core/public/js/layout/main.js

@@ -1,5 +1,44 @@
-var json
+var json;
 var itemselected = false;
+var midas = midas || {};
+
+// Create the callbacks data structure
+midas.callbacks = midas.callbacks || {};
+
+/**
+ * Register a callback function from a module
+ * @param name The name of the callback
+ * @param module The module name registering the callback
+ * @param fn The callback function
+ */
+midas.registerCallback = function(name, module, fn)
+{
+  if(midas.callbacks[name] == undefined)
+    {
+    midas.callbacks[name] = {};
+    }
+  midas.callbacks[name][module] = fn;
+}
+
+/**
+ * Perform a callback.
+ * @param name The name of the callback to run.
+ * @param args A json object that will be passed to the registered callbacks.
+ * @return A json object whose keys are the module names and whose values are
+ * the return value for that module's registered callback.
+ */
+midas.doCallback = function(name, args)
+{
+  if(midas.callbacks[name] == undefined)
+    {
+    return {};
+    }
+  var retVal = {};
+  $.each(midas.callbacks[name], function(index, value) {
+    retVal[index] = value(args);
+    });
+  return retVal;
+}
 
 // Prevent error if console.log is called
 if (typeof console != "object") {