2a09d1a4
 liuqimichale
添加宜春 天水 宣化
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/**
* mux.js
*
* Copyright (c) 2014 Brightcove
* All rights reserved.
*
* A lightweight readable stream implemention that handles event dispatching.
* Objects that inherit from streams should call init in their constructors.
*/
'use strict';
var Stream = function() {
this.init = function() {
var listeners = {};
/**
* Add a listener for a specified event type.
* @param type {string} the event name
* @param listener {function} the callback to be invoked when an event of
* the specified type occurs
*/
this.on = function(type, listener) {
if (!listeners[type]) {
listeners[type] = [];
}
listeners[type] = listeners[type].concat(listener);
};
/**
* Remove a listener for a specified event type.
* @param type {string} the event name
* @param listener {function} a function previously registered for this
* type of event through `on`
*/
this.off = function(type, listener) {
var index;
if (!listeners[type]) {
return false;
}
index = listeners[type].indexOf(listener);
listeners[type] = listeners[type].slice();
listeners[type].splice(index, 1);
return index > -1;
};
/**
* Trigger an event of the specified type on this stream. Any additional
* arguments to this function are passed as parameters to event listeners.
* @param type {string} the event name
*/
this.trigger = function(type) {
var callbacks, i, length, args;
callbacks = listeners[type];
if (!callbacks) {
return;
}
// Slicing the arguments on every invocation of this method
// can add a significant amount of overhead. Avoid the
// intermediate object creation for the common case of a
// single callback argument
if (arguments.length === 2) {
length = callbacks.length;
for (i = 0; i < length; ++i) {
callbacks[i].call(this, arguments[1]);
}
} else {
args = [];
i = arguments.length;
for (i = 1; i < arguments.length; ++i) {
args.push(arguments[i]);
}
length = callbacks.length;
for (i = 0; i < length; ++i) {
callbacks[i].apply(this, args);
}
}
};
/**
* Destroys the stream and cleans up.
*/
this.dispose = function() {
listeners = {};
};
};
};
/**
* Forwards all `data` events on this stream to the destination stream. The
* destination stream should provide a method `push` to receive the data
* events as they arrive.
* @param destination {stream} the stream that will receive all `data` events
* @param autoFlush {boolean} if false, we will not call `flush` on the destination
* when the current stream emits a 'done' event
* @see http://nodejs.org/api/stream.html#stream_readable_pipe_destination_options
*/
Stream.prototype.pipe = function(destination) {
this.on('data', function(data) {
destination.push(data);
});
this.on('done', function(flushSource) {
destination.flush(flushSource);
});
return destination;
};
// Default stream functions that are expected to be overridden to perform
// actual work. These are provided by the prototype as a sort of no-op
// implementation so that we don't have to check for their existence in the
// `pipe` function above.
Stream.prototype.push = function(data) {
this.trigger('data', data);
};
Stream.prototype.flush = function(flushSource) {
this.trigger('done', flushSource);
};
module.exports = Stream;
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