Current File : /www/varak.net/wiki.varak.net/extensions/VisualEditor/lib/ve/src/ve.Scheduler.js
/*!
* VisualEditor Scheduler class.
*
* @copyright 2011-2016 VisualEditor Team and others; see http://ve.mit-license.org
*/
/**
* @class
*
* @constructor
*/
ve.Scheduler = function VeScheduler() {
// TODO: If we decide to start tracking setTimeout calls within actions, we'll
// need to keep state here.
};
/* Inheritance */
OO.initClass( ve.Scheduler );
/* Static Properties */
ve.Scheduler.static.maxDelay = 1000;
/* Methods */
/**
* Perform an action and await a callback when its side-effects are complete
*
* The ultimate definition of "side-effects are complete" is "when the chain of async
* actions / setTimeout calls spawned by the action finish". This is intended to be a way
* to wrap non-promise code in promises and have it mostly work.
*
* As currently implemented, we use completionTest as our sole signal. This is not
* guaranteed to remain true. Don't write code that assumes completionTest will be
* called, or which tests for a completely unrelated condition.
*
* The signature of this function is designed to let you leave signals about your intent.
* You pass the action with side-effects in, and explain the conditions that must be met
* for further actions to be taken.
*
* @param {Function} immediateAction Action to take whose status we want to track
* @param {Function} completionTest Tests whether action is complete; ideally very cheap;
* there's no guarantee that we will ever call this, if we can sense completion in
* some other way
* @param {number} [delayHint] Optional hint about how long to wait between tests
* @return {jQuery.Promise} Promise that resolves when the completionTest returns true.
* Note that this _could_ already be resolved when it's returned, so there's no
* guarantee that your `done` call on it will be delayed.
*/
ve.Scheduler.prototype.schedule = function ( immediateAction, completionTest, delayHint ) {
var deferred = $.Deferred(),
startTime = this.now(),
testThenAct = function () {
var complete;
try {
complete = completionTest();
} catch ( e ) {
deferred.reject( e );
return;
}
if ( complete ) {
deferred.resolve();
return;
}
if ( this.now() - startTime > this.constructor.static.maxDelay ) {
deferred.reject();
return;
}
this.postpone( testThenAct, delayHint );
}.bind( this );
// In the future, we may want to expand this to track whether other async calls
// were made within the action.
immediateAction();
// Spin up the test cycle
testThenAct();
return deferred.promise();
};
/**
* Make a postponed call.
*
* This is a separate function because that makes it easier to replace when testing
*
* @param {Function} callback The function to call
* @param {number} delay Delay before running callback
* @return {number} Unique postponed timeout id
*/
ve.Scheduler.prototype.postpone = function ( callback, delay ) {
return setTimeout( callback, delay );
};
/**
* Obtain the current timestamp
*
* This is a separate function because that makes it easier to replace when testing
*
* @return {number} Current timestamp in milliseconds
*/
ve.Scheduler.prototype.now = function () {
return Date.now();
};
/* Initialization */
ve.scheduler = new ve.Scheduler();
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