1 files changed, 173 insertions, 0 deletions
diff --git a/js/lib/hooks.js b/js/lib/hooks.js
new file mode 100644
index 000000000..5e1808e22
--- /dev/null
+++ b/js/lib/hooks.js
@@ -0,0 +1,173 @@
+/*
+ * Javascript hook interface
+ */
+
+elgg.provide('elgg.config.hooks');
+elgg.provide('elgg.config.instant_hooks');
+elgg.provide('elgg.config.triggered_hooks');
+
+/**
+ * Registers a hook handler with the event system.
+ *
+ * The special keyword "all" can be used for either the name or the type or both
+ * and means to call that handler for all of those hooks.
+ *
+ * Note that handlers registering for instant hooks will be executed immediately if the instant
+ * hook has been previously triggered.
+ *
+ * @param {String}   name     Name of the plugin hook to register for
+ * @param {String}   type     Type of the event to register for
+ * @param {Function} handler  Handle to call
+ * @param {Number}   priority Priority to call the event handler
+ * @return {Bool}
+ */
+elgg.register_hook_handler = function(name, type, handler, priority) {
+	elgg.assertTypeOf('string', name);
+	elgg.assertTypeOf('string', type);
+	elgg.assertTypeOf('function', handler);
+
+	if (!name || !type) {
+		return false;
+	}
+
+	var priorities =  elgg.config.hooks;
+
+	elgg.provide(name + '.' + type, priorities);
+
+	if (!(priorities[name][type] instanceof elgg.ElggPriorityList)) {
+		priorities[name][type] = new elgg.ElggPriorityList();
+	}
+
+	// call if instant and already triggered.
+	if (elgg.is_instant_hook(name, type) && elgg.is_triggered_hook(name, type)) {
+		handler(name, type, null, null);
+	}
+
+	return priorities[name][type].insert(handler, priority);
+};
+
+/**
+ * Emits a hook.
+ *
+ * Loops through all registered hooks and calls the handler functions in order.
+ * Every handler function will always be called, regardless of the return value.
+ *
+ * @warning Handlers take the same 4 arguments in the same order as when calling this function.
+ * This is different from the PHP version!
+ *
+ * @note Instant hooks do not support params or values.
+ *
+ * Hooks are called in this order:
+ *	specifically registered (event_name and event_type match)
+ *	all names, specific type
+ *	specific name, all types
+ *	all names, all types
+ *
+ * @param {String} name   Name of the hook to emit
+ * @param {String} type   Type of the hook to emit
+ * @param {Object} params Optional parameters to pass to the handlers
+ * @param {Object} value  Initial value of the return. Can be mangled by handlers
+ *
+ * @return {Bool}
+ */
+elgg.trigger_hook = function(name, type, params, value) {
+	elgg.assertTypeOf('string', name);
+	elgg.assertTypeOf('string', type);
+
+	// mark as triggered
+	elgg.set_triggered_hook(name, type);
+
+	// default to true if unpassed
+	value = value || true;
+
+	var hooks = elgg.config.hooks,
+		tempReturnValue = null,
+		returnValue = value,
+		callHookHandler = function(handler) {
+			tempReturnValue = handler(name, type, params, value);
+		};
+
+	elgg.provide(name + '.' + type, hooks);
+	elgg.provide('all.' + type, hooks);
+	elgg.provide(name + '.all', hooks);
+	elgg.provide('all.all', hooks);
+
+	var hooksList = [];
+	
+	if (name != 'all' && type != 'all') {
+		hooksList.push(hooks[name][type]);
+	}
+
+	if (type != 'all') {
+		hooksList.push(hooks['all'][type]);
+	}
+
+	if (name != 'all') {
+		hooksList.push(hooks[name]['all']);
+	}
+
+	hooksList.push(hooks['all']['all']);
+
+	hooksList.every(function(handlers) {
+		if (handlers instanceof elgg.ElggPriorityList) {
+			handlers.forEach(callHookHandler);
+		}
+		return true;
+	});
+
+	return (tempReturnValue != null) ? tempReturnValue : returnValue;
+};
+
+/**
+ * Registers a hook as an instant hook.
+ *
+ * After being trigger once, registration of a handler to an instant hook will cause the
+ * handle to be executed immediately.
+ *
+ * @note Instant hooks must be triggered without params or defaults. Any params or default
+ * passed will *not* be passed to handlers executed upon registration.
+ *
+ * @param {String} name The hook name.
+ * @param {String} type The hook type.
+ * @return {Int}
+ */
+elgg.register_instant_hook = function(name, type) {
+	elgg.assertTypeOf('string', name);
+	elgg.assertTypeOf('string', type);
+
+	return elgg.push_to_object_array(elgg.config.instant_hooks, name, type);
+};
+
+/**
+ * Is this hook registered as an instant hook?
+ *
+ * @param {String} name The hook name.
+ * @param {String} type The hook type.
+ */
+elgg.is_instant_hook = function(name, type) {
+	return elgg.is_in_object_array(elgg.config.instant_hooks, name, type);
+};
+
+/**
+ * Records that a hook has been triggered.
+ *
+ * @param {String} name The hook name.
+ * @param {String} type The hook type.
+ */
+elgg.set_triggered_hook = function(name, type) {
+	return elgg.push_to_object_array(elgg.config.triggered_hooks, name, type);
+};
+
+/**
+ * Has this hook been triggered yet?
+ *
+ * @param {String} name The hook name.
+ * @param {String} type The hook type.
+ */
+elgg.is_triggered_hook = function(name, type) {
+	return elgg.is_in_object_array(elgg.config.triggered_hooks, name, type);
+};
+
+elgg.register_instant_hook('init', 'system');
+elgg.register_instant_hook('ready', 'system');
+elgg.register_instant_hook('boot', 'system');