All files / src ve.Scheduler.js

96.15% Statements 25/26
100% Branches 4/4
80% Functions 4/5
96.15% Lines 25/26

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110                      1x             1x       1x                                                       1x 4x 4x 4x   10x 10x   1x 1x   9x 2x 2x   7x 1x 1x   6x         4x     4x   4x                       1x 6x                   1x           1x  
/*!
 * VisualEditor Scheduler class.
 *
 * @copyright See AUTHORS.txt
 */
 
/**
 * @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 = ve.createDeferred(),
		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();