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74 lines
1.5 KiB
74 lines
1.5 KiB
/* |
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MIT License http://www.opensource.org/licenses/mit-license.php |
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Author Tobias Koppers @sokra |
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*/ |
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"use strict"; |
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/** @typedef {import("../Cache").Etag} Etag */ |
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class MergedEtag { |
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/** |
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* @param {Etag} a first |
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* @param {Etag} b second |
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*/ |
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constructor(a, b) { |
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this.a = a; |
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this.b = b; |
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} |
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toString() { |
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return `${this.a.toString()}|${this.b.toString()}`; |
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} |
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} |
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const dualObjectMap = new WeakMap(); |
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const objectStringMap = new WeakMap(); |
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/** |
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* @param {Etag} a first |
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* @param {Etag} b second |
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* @returns {Etag} result |
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*/ |
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const mergeEtags = (a, b) => { |
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if (typeof a === "string") { |
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if (typeof b === "string") { |
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return `${a}|${b}`; |
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} else { |
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const temp = b; |
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b = a; |
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a = temp; |
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} |
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} else { |
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if (typeof b !== "string") { |
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// both a and b are objects |
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let map = dualObjectMap.get(a); |
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if (map === undefined) { |
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dualObjectMap.set(a, (map = new WeakMap())); |
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} |
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const mergedEtag = map.get(b); |
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if (mergedEtag === undefined) { |
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const newMergedEtag = new MergedEtag(a, b); |
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map.set(b, newMergedEtag); |
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return newMergedEtag; |
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} else { |
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return mergedEtag; |
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} |
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} |
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} |
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// a is object, b is string |
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let map = objectStringMap.get(a); |
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if (map === undefined) { |
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objectStringMap.set(a, (map = new Map())); |
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} |
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const mergedEtag = map.get(b); |
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if (mergedEtag === undefined) { |
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const newMergedEtag = new MergedEtag(a, b); |
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map.set(b, newMergedEtag); |
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return newMergedEtag; |
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} else { |
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return mergedEtag; |
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} |
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}; |
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module.exports = mergeEtags;
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