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137 lines
3.8 KiB
137 lines
3.8 KiB
/**
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* Publish/Subscribe event system for anonymous message passing
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*
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*/
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if (typeof bobj == 'undefined') {
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bobj = {};
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}
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if (typeof bobj.event == 'undefined') {
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bobj.event = {};
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bobj.event._topicSubscriptions = {};
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bobj.event._globalSubscriptions = [];
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}
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/**
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* Publish an event for subscribers to receive
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*
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* @param topic [String] The event topic
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* @param arguments Unnamed args will be passed to subscribers
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*/
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bobj.event.publish = function(topic) {
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var args = bobj.slice(arguments, 1);
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var topicSubs = bobj.event._topicSubscriptions[topic];
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if (topicSubs) {
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for (var i = 0; i < topicSubs.length; ++i) {
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topicSubs[i]._notify.apply(null, args);
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}
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}
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var globalSubs = bobj.event._globalSubscriptions;
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for (var j = 0; j < globalSubs.length; ++j) {
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globalSubs[j]._notify.apply(null, args);
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}
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};
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/**
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* Subscribe to a topic
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*
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* @param topic [String] The event topic
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* @param callback [Function] Function to be call with topic's arguments
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* @param target [Object] Object to notify (requires methName)
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* @param methName [String] Name of method to call when target is notified
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*
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* Arguments may be passed in any of the following combinations:
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* (topic, target, methName)
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* (topic, callback)
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* (target, methName)
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* (callback)
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*
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* When a topic is not specified, the subscriber receives all topics
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*
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* @return Subscription object that can be used to unsubscribe
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*/
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bobj.event.subscribe = function() {
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var nmlr = bobj.event.subscribe._normalizer;
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if (!nmlr) {
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nmlr = bobj.event.subscribe._normalizer = new bobj.ArgumentNormalizer();
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// If 3 args: (topic, target, methName)
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nmlr.addRule('topic', 'target', 'methName');
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// If 2 args and first is a string: (topic, callback)
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nmlr.addRule([bobj.isString, 'topic'], 'callback');
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// If 2 args: (target, methName)
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nmlr.addRule('target', 'methName');
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// If 1 arg: (callback)
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nmlr.addRule('callback');
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}
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return bobj.event.kwSubscribe(nmlr.normalizeArray(arguments));
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};
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/**
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* Subscribe to a topic using keyword arguments
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*
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* @param kwArgs.topic [String] The event topic
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* @param kwArgs.callback [Function] Function to be call with topic's arguments
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* @param kwArgs.target [Object] Object to notify (requires methName)
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* @param kwArgs.methName [String] Name of method to call when target is notified
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*
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* @see bobj.event.subscribe
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*
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* @return Subscription object that can be used to unsubscribe
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*/
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bobj.event.kwSubscribe = function(kwArgs) {
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var bind = MochiKit.Base.bind;
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var subscription = {};
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if (kwArgs.callback) {
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subscription._notify = kwArgs.callback;
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}
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else {
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subscription._notify = bind(kwArgs.target[kwArgs.methName], kwArgs.target);
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}
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if (kwArgs.topic) {
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subscription.topic = kwArgs.topic;
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var subs = bobj.event._topicSubscriptions;
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if (!subs[kwArgs.topic]) {
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subs[kwArgs.topic] = [];
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}
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subs[kwArgs.topic].push(subscription);
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}
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else {
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bobj.event._globalSubscriptions.push(subscription);
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}
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return subscription;
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};
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/**
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* Unsubscribe from a topic
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*
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* @param subscription [Subscription] The object returned by subscribe
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*/
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bobj.event.unsubscribe = function(subscription) {
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var subsList = bobj.event._globalSubscriptions;
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if (subscription.topic) {
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subsList = bobj.event._topicSubscriptions[subscription.topic];
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}
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if (subsList) {
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var idx = MochiKit.Base.findIdentical(subsList, subscription);
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if (idx != -1) {
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subsList.splice(idx, 1); // remove the subscription
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delete subscription._notify; // prevent leaks
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}
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}
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};
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