/*---------------------------------------------------------------------------------------------
 *  Copyright (c) Microsoft Corporation. All rights reserved.
 *  Licensed under the MIT License. See License.txt in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
import { CancellationTokenSource } from './cancellation.js';
export class Cache {
    task;
    result = null;
    constructor(task) {
        this.task = task;
    }
    get() {
        if (this.result) {
            return this.result;
        }
        const cts = new CancellationTokenSource();
        const promise = this.task(cts.token);
        this.result = {
            promise,
            dispose: () => {
                this.result = null;
                cts.cancel();
                cts.dispose();
            }
        };
        return this.result;
    }
}
export function identity(t) {
    return t;
}
/**
 * Uses a LRU cache to make a given parametrized function cached.
 * Caches just the last key/value.
*/
export class LRUCachedFunction {
    lastCache = undefined;
    lastArgKey = undefined;
    _fn;
    _computeKey;
    constructor(arg1, arg2) {
        if (typeof arg1 === 'function') {
            this._fn = arg1;
            this._computeKey = identity;
        }
        else {
            this._fn = arg2;
            this._computeKey = arg1.getCacheKey;
        }
    }
    get(arg) {
        const key = this._computeKey(arg);
        if (this.lastArgKey !== key) {
            this.lastArgKey = key;
            this.lastCache = this._fn(arg);
        }
        return this.lastCache;
    }
}
/**
 * Uses an unbounded cache to memoize the results of the given function.
*/
export class CachedFunction {
    _map = new Map();
    _map2 = new Map();
    get cachedValues() {
        return this._map;
    }
    _fn;
    _computeKey;
    constructor(arg1, arg2) {
        if (typeof arg1 === 'function') {
            this._fn = arg1;
            this._computeKey = identity;
        }
        else {
            this._fn = arg2;
            this._computeKey = arg1.getCacheKey;
        }
    }
    get(arg) {
        const key = this._computeKey(arg);
        if (this._map2.has(key)) {
            return this._map2.get(key);
        }
        const value = this._fn(arg);
        this._map.set(arg, value);
        this._map2.set(key, value);
        return value;
    }
}
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