/**
* @license
* Copyright 2016 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
goog.provide('shaka.util.DelayedTick');
/**
* This class wraps a function so that we can defer executing the function by X
* seconds.
*
* @final
*/
shaka.util.DelayedTick = class {
/**
* @param {function()} onTick
*/
constructor(onTick) {
/** @private {function()} */
this.onTick_ = onTick;
/** @private {?function()} */
this.cancelPending_ = null;
}
/**
* Call |onTick| after |delayInSeconds| has elapsed. If there is already a
* pending call to |onTick|, the pending call will be canceled.
*
* @param {number} delayInSeconds
* @return {!shaka.util.DelayedTick}
*/
tickAfter(delayInSeconds) {
// We only want one timeout set at a time, so make sure no other timeouts
// are running.
this.stop();
// We will wrap these values in a function to allow us to cancel the timeout
// we are about to create.
let alive = true;
let timeoutId = null;
this.cancelPending_ = () => {
window.clearTimeout(timeoutId);
alive = false;
};
// For some reason, a timeout may still execute after we have cleared it in
// our tests. We will wrap the callback so that we can double-check our
// |alive| flag.
const onTick = () => {
if (alive) {
this.onTick_();
}
};
timeoutId = window.setTimeout(onTick, delayInSeconds * 1000);
return this;
}
/**
* Cancel any pending calls to |onTick|. If there are no pending calls to
* |onTick|, this will be a no-op.
*/
stop() {
if (this.cancelPending_) {
this.cancelPending_();
this.cancelPending_ = null;
}
}
};