src/vs/base/common/lazy.ts

57 LOC · 57 covered · 0 uncovered · 12 ranges · 17530 concepts · 6 introducers · 10898 tests

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  /*---------------------------------------------------------------------------------------------
  
lazy.ts ×3

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   *  Copyright (c) Microsoft Corporation. All rights reserved.
  
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   *  Licensed under the MIT License. See License.txt in the project root for license information.
  
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   *--------------------------------------------------------------------------------------------*/
  
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  enum LazyValueState {
  
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  	Uninitialized,
  
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  	Running,
  
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  	Completed,
  
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  }
  
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  export class Lazy<T> {
  
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  	private _state = LazyValueState.Uninitialized;
  
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  	private _value?: T;
  
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  	private _error: Error | undefined;
  
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  	constructor(
  
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  		private readonly executor: () => T,
  
lazy.ts ×1

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  	) { }
  
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lazy.ts ×3

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  	/**
  
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  	 * True if the lazy value has been resolved.
  
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  	 */
  
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  	get hasValue(): boolean { return this._state === LazyValueState.Completed; }
  
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  	/**
  
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  	 * Get the wrapped value.
  
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  	 *
  
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  	 * This will force evaluation of the lazy value if it has not been resolved yet. Lazy values are only
  
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  	 * resolved once. `getValue` will re-throw exceptions that are hit while resolving the value
  
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  	 */
  
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  	get value(): T {
  
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  		if (this._state === LazyValueState.Uninitialized) {
  
lazy.ts ×4

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  			this._state = LazyValueState.Running;
  
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  			try {
  
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  				this._value = this.executor();
  
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  			} catch (err) {
  
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  				this._error = err;
  
lazy.ts ×2

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  			} finally {
  
lazy.ts ×4

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  				this._state = LazyValueState.Completed;
  
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  			}
  
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  		} else if (this._state === LazyValueState.Running) {
  
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  			throw new Error('Cannot read the value of a lazy that is being initialized');
  
lazy.ts ×1

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  		}
  
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lazy.ts ×4

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  		if (this._error) {
  
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  			throw this._error;
  
lazy.ts ×2

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  		}
  
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  		return this._value!;
  
lazy.ts ×1

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  	}
  
lazy.ts ×4

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lazy.ts ×3

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  	/**
  
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  	 * Get the wrapped value without forcing evaluation.
  
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  	 */
  
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  	get rawValue(): T | undefined { return this._value; }
  
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  }