68 lines
1.5 KiB
JavaScript
68 lines
1.5 KiB
JavaScript
/**
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* Creates a cache that evicts keys in fifo order
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* @param size {Number}
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*/
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function makeFifoCache(
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size,
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)
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{
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// Maintain a fifo queue of keys, we cannot rely on Object.keys as the browser may not support it.
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let evictionOrder = [];
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let cache = {};
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return {
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add(key, value) {
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while (evictionOrder.length >= size) {
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// shift is O(n) but this is small size and only happens if we are
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// exceeding the cache size so it should be fine.
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const evictCandidate = evictionOrder.shift();
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if (evictCandidate !== undefined) {
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// eslint-disable-next-line @typescript-eslint/no-dynamic-delete
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delete cache[evictCandidate];
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}
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}
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// in case we have a collision, delete the old key.
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if (cache[key]) {
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this.delete(key);
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}
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evictionOrder.push(key);
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cache[key] = value;
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},
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clear() {
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cache = {};
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evictionOrder = [];
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},
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get(key) {
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return cache[key];
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},
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size() {
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return evictionOrder.length;
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},
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// Delete cache key and return true if it existed, false otherwise.
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delete(key) {
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if (!cache[key]) {
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return false;
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}
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// eslint-disable-next-line @typescript-eslint/no-dynamic-delete
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delete cache[key];
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for (let i = 0; i < evictionOrder.length; i++) {
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if (evictionOrder[i] === key) {
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evictionOrder.splice(i, 1);
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break;
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}
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}
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return true;
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},
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};
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}
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export { makeFifoCache };
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//# sourceMappingURL=cache.js.map
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