Author: johnh
Date: Tue Jul 12 19:10:30 2011
New Revision: 1145725
URL: http://svn.apache.org/viewvc?rev=1145725&view=rev
Log:
Adds support for exporting deferred symbols to exportJs.
By default this functionality is not used. Corresponding changes to
ExportJsProcessor are required for this to be used end-to-end.
Modified:
shindig/trunk/features/src/main/javascript/features/exportjs/exportjs.js
Modified:
shindig/trunk/features/src/main/javascript/features/exportjs/exportjs.js
URL:
http://svn.apache.org/viewvc/shindig/trunk/features/src/main/javascript/features/exportjs/exportjs.js?rev=1145725&r1=1145724&r2=1145725&view=diff
==============================================================================
--- shindig/trunk/features/src/main/javascript/features/exportjs/exportjs.js
(original)
+++ shindig/trunk/features/src/main/javascript/features/exportjs/exportjs.js
Tue Jul 12 19:10:30 2011
@@ -46,11 +46,24 @@
* feature directive: <exports type="js">gadgets.foo.bar</exports>
* gadgets.foo = {};
* gadgets.foo.bar = function() { ... };
+ *
+ * Also supports deferred symbol binding. When deferred mode is specified,
+ * undefined symbols being defined in context here are treated as functions
+ * with no return value. Stub functions are created for them at the
+ * specified named endpoint. These functions enqueue requests and immediately
+ * return. When the real method implementation is loaded and exported,
+ * the real method is executed with the enqueued arguments.
*/
-function exportJs(namespace, components, opt_props) {
+function exportJs(namespace, components, opt_props, opt_defer) {
+ var JSL = '___jsl';
+ var DEFER_KEY = 'df';
var base = window;
var prevBase = null;
var nsParts = namespace.split('.');
+ var sliceFn = [].slice;
+
+ // Set up defer function queue.
+ var deferMap = ((window[JSL] = window[JSL] || {})[DEFER_KEY] =
window[JSL][DEFER_KEY] || {});
for (var i = 0, part; part = nsParts.shift(); i++) {
base[part] = base[part] || components[i] || {};
@@ -58,18 +71,51 @@ function exportJs(namespace, components,
base = base[part];
}
- var exportProps = function(root) {
+ /**
+ * Exports properties/functions on the provided base object.
+ * If a property to export is a function, does not exist in its full
+ * form, and deferred mode is enabled, a stub is created.
+ * The stub enqueues requests that are executed by the real method
+ * when it is loaded and exported.
+ *
+ * @param root {Object} Base object to which to attach properties.
+ */
+ function exportProps(root) {
var props = opt_props || {};
for (var prop in props) {
- if (props.hasOwnProperty(prop) && root.hasOwnProperty(prop)) {
- if (!root[props[prop]]) root[props[prop]] = root[prop];
+ if (props.hasOwnProperty(prop)) {
+ var curalias = props[prop];
+ var fulltok = namespace + '.' + curalias;
+ if (root.hasOwnProperty(prop)) {
+ if (!root[curalias]) {
+ root[curalias] = root[prop];
+ } else if (!opt_defer && deferMap[fulltok]) {
+ // Executes enqueued requests for the method,
+ // then replaces the export.
+ deferMap[fulltok](root, root[prop]);
+ delete deferMap[fulltok];
+ root[curalias] = root[prop];
+ }
+ } else if (opt_defer) {
+ root[prop] = (function() {
+ var queue = [];
+ var ret = function() {
+ queue.push(sliceFn.call(arguments, 0));
+ };
+ deferMap[fulltok] = function(ctx, method) {
+ for (var i = 0, len = queue.length; i < len; ++i) {
+ method.apply(ctx, queue[i]);
+ }
+ };
+ return ret;
+ })();
+ }
}
}
};
if (typeof base === 'object') {
exportProps(base);
-
} else if (typeof base === 'function') {
var exportedFn = function() {
var result = base.apply(null, arguments);
