mirror of
https://github.com/shaka-project/shaka-player.git
synced 2026-06-14 15:56:38 +03:00
Wojciech Tyczyński
e0a57bb27d
Due to usage of `==` instead of `===` Lazy utility does not work correctly with null generators, despite of what is stated in documentation.
45 lines
988 B
JavaScript
45 lines
988 B
JavaScript
/*! @license
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* Shaka Player
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* Copyright 2016 Google LLC
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* SPDX-License-Identifier: Apache-2.0
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*/
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goog.provide('shaka.util.Lazy');
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goog.require('goog.asserts');
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/**
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* @summary
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* This contains a single value that is lazily generated when it is first
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* requested. This can store any value except "undefined".
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*
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* @template T
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*/
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shaka.util.Lazy = class {
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/** @param {function():T} gen */
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constructor(gen) {
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/** @private {function():T} */
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this.gen_ = gen;
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/** @private {T|undefined} */
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this.value_ = undefined;
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}
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/** @return {T} */
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value() {
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if (this.value_ === undefined) {
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// Compiler complains about unknown fields without this cast.
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this.value_ = /** @type {*} */ (this.gen_());
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goog.asserts.assert(
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this.value_ !== undefined, 'Unable to create lazy value');
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}
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return this.value_;
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}
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/** Resets the value of the lazy function, so it has to be remade. */
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reset() {
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this.value_ = undefined;
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}
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};
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