Current File : /home/opti/workflow/node_modules/aws-sdk/lib/sequential_executor.js
var AWS = require('./core');
var domain = AWS.util.nodeRequire('domain');
/**
* @!method on(eventName, callback)
* Registers an event listener callback for the event given by `eventName`.
* Parameters passed to the callback function depend on the individual event
* being triggered. See the event documentation for those parameters.
*
* @param eventName [String] the event name to register the listener for
* @param callback [Function] the listener callback function
* @return [AWS.SequentialExecutor] the same object for chaining
*/
AWS.SequentialExecutor = AWS.util.inherit({
constructor: function SequentialExecutor() {
this.domain = domain && domain.active;
this._events = {};
},
/**
* @api private
*/
listeners: function listeners(eventName) {
return this._events[eventName] ? this._events[eventName].slice(0) : [];
},
on: function on(eventName, listener) {
if (this._events[eventName]) {
this._events[eventName].push(listener);
} else {
this._events[eventName] = [listener];
}
return this;
},
/**
* @api private
*/
onAsync: function onAsync(eventName, listener) {
listener._isAsync = true;
return this.on(eventName, listener);
},
removeListener: function removeListener(eventName, listener) {
var listeners = this._events[eventName];
if (listeners) {
var length = listeners.length;
var position = -1;
for (var i = 0; i < length; ++i) {
if (listeners[i] === listener) {
position = i;
}
}
if (position > -1) {
listeners.splice(position, 1);
}
}
return this;
},
removeAllListeners: function removeAllListeners(eventName) {
if (eventName) {
delete this._events[eventName];
} else {
this._events = {};
}
return this;
},
/**
* @api private
*/
emit: function emit(eventName, eventArgs, doneCallback) {
if (!doneCallback) doneCallback = this.unhandledErrorCallback;
var listeners = this.listeners(eventName);
var count = listeners.length;
this.callListeners(listeners, eventArgs, doneCallback);
return count > 0;
},
/**
* @api private
*/
callListeners: function callListeners(listeners, args, doneCallback) {
if (listeners.length === 0) {
doneCallback.call(this);
return;
}
var self = this, listener = listeners.shift();
if (listener._isAsync) { // asynchronous listener
var callNextListener = function(err) {
if (err) {
doneCallback.call(self, err);
} else {
self.callListeners(listeners, args, doneCallback);
}
};
listener.apply(self, args.concat([callNextListener]));
} else { // synchronous listener
try {
listener.apply(self, args);
self.callListeners(listeners, args, doneCallback);
} catch (err) {
doneCallback.call(self, err);
}
}
},
/**
* Adds or copies a set of listeners from another list of
* listeners or SequentialExecutor object.
*
* @param listeners [map<String,Array<Function>>, AWS.SequentialExecutor]
* a list of events and callbacks, or an event emitter object
* containing listeners to add to this emitter object.
* @return [AWS.SequentialExecutor] the emitter object, for chaining.
* @example Adding listeners from a map of listeners
* emitter.addListeners({
* event1: [function() { ... }, function() { ... }],
* event2: [function() { ... }]
* });
* emitter.emit('event1'); // emitter has event1
* emitter.emit('event2'); // emitter has event2
* @example Adding listeners from another emitter object
* var emitter1 = new AWS.SequentialExecutor();
* emitter1.on('event1', function() { ... });
* emitter1.on('event2', function() { ... });
* var emitter2 = new AWS.SequentialExecutor();
* emitter2.addListeners(emitter1);
* emitter2.emit('event1'); // emitter2 has event1
* emitter2.emit('event2'); // emitter2 has event2
*/
addListeners: function addListeners(listeners) {
var self = this;
// extract listeners if parameter is an SequentialExecutor object
if (listeners._events) listeners = listeners._events;
AWS.util.each(listeners, function(event, callbacks) {
if (typeof callbacks === 'function') callbacks = [callbacks];
AWS.util.arrayEach(callbacks, function(callback) {
self.on(event, callback);
});
});
return self;
},
/**
* Registers an event with {on} and saves the callback handle function
* as a property on the emitter object using a given `name`.
*
* @param name [String] the property name to set on this object containing
* the callback function handle so that the listener can be removed in
* the future.
* @param (see on)
* @return (see on)
* @example Adding a named listener DATA_CALLBACK
* var listener = function() { doSomething(); };
* emitter.addNamedListener('DATA_CALLBACK', 'data', listener);
*
* // the following prints: true
* console.log(emitter.DATA_CALLBACK == listener);
*/
addNamedListener: function addNamedListener(name, eventName, callback) {
this[name] = callback;
this.addListener(eventName, callback);
return this;
},
/**
* @api private
*/
addNamedAsyncListener: function addNamedAsyncListener(name, eventName, callback) {
callback._isAsync = true;
return this.addNamedListener(name, eventName, callback);
},
/**
* Helper method to add a set of named listeners using
* {addNamedListener}. The callback contains a parameter
* with a handle to the `addNamedListener` method.
*
* @callback callback function(add)
* The callback function is called immediately in order to provide
* the `add` function to the block. This simplifies the addition of
* a large group of named listeners.
* @param add [Function] the {addNamedListener} function to call
* when registering listeners.
* @example Adding a set of named listeners
* emitter.addNamedListeners(function(add) {
* add('DATA_CALLBACK', 'data', function() { ... });
* add('OTHER', 'otherEvent', function() { ... });
* add('LAST', 'lastEvent', function() { ... });
* });
*
* // these properties are now set:
* emitter.DATA_CALLBACK;
* emitter.OTHER;
* emitter.LAST;
*/
addNamedListeners: function addNamedListeners(callback) {
var self = this;
callback(
function() {
self.addNamedListener.apply(self, arguments);
},
function() {
self.addNamedAsyncListener.apply(self, arguments);
}
);
return this;
},
/**
* @api private
*/
unhandledErrorCallback: function unhandledErrorCallback(err) {
if (err) {
if (domain && this.domain instanceof domain.Domain) {
err.domainEmitter = this;
err.domain = this.domain;
err.domainThrown = false;
this.domain.emit('error', err);
} else {
throw err;
}
}
}
});
/**
* {on} is the prefered method.
* @api private
*/
AWS.SequentialExecutor.prototype.addListener = AWS.SequentialExecutor.prototype.on;
module.exports = AWS.SequentialExecutor;
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