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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
/**
* @constructor
* @class FunctionSequence to invoke steps in sequence
*
* @param steps array of functions to invoke in parallel
* @param callback callback to invoke on success
* @param failureCallback callback to invoke on failure
*/
function FunctionParallel(name, steps, logger, callback, failureCallback) {
// Private variables hidden in closure
this.currentStepIdx_ = -1;
this.failed_ = false;
this.steps_ = steps;
this.callback_ = callback;
this.failureCallback_ = failureCallback;
this.logger = logger;
this.name = name;
this.remaining = this.steps_.length;
this.nextStep = this.nextStep_.bind(this);
this.onError = this.onError_.bind(this);
this.apply = this.start.bind(this);
}
/**
* Error handling function, which fires error callback.
*
* @param err error message
*/
FunctionParallel.prototype.onError_ = function(err) {
if (!this.failed_) {
this.failed_ = true;
this.failureCallback_(err);
}
};
/**
* Advances to next step. This method should not be used externally. In external
* cases should be used nextStep function, which is defined in closure and thus
* has access to internal variables of functionsequence.
*/
FunctionParallel.prototype.nextStep_ = function() {
if (--this.remaining == 0 && !this.failed_) {
this.callback_();
}
};
/**
* This function should be called only once on start, so start all the children
* at once
*/
FunctionParallel.prototype.start = function(var_args) {
this.logger.vlog('Starting [' + this.steps_.length + '] parallel tasks with '
+ arguments.length + ' argument(s)');
if (this.logger.verbose) {
for (var j = 0; j < arguments.length; j++) {
this.logger.vlog(arguments[j]);
}
}
for (var i=0; i < this.steps_.length; i++) {
this.logger.vlog('Attempting to start step [' + this.steps_[i].name + ']');
try {
this.steps_[i].apply(this, arguments);
} catch(e) {
this.onError(e.toString());
}
}
};
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