141 lines
3.4 KiB
JavaScript
141 lines
3.4 KiB
JavaScript
const LRU = require('lru-cache');
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const _ = require('lodash');
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const lru_params = [ 'max', 'maxAge', 'length', 'dispose', 'stale' ];
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const deepFreeze = require('./lib/freeze');
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const vfs = require('very-fast-args');
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module.exports = function (options) {
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const cache = new LRU(_.pick(options, lru_params));
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const load = options.load;
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const hash = options.hash;
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const bypass = options.bypass;
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const itemMaxAge = options.itemMaxAge;
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const freeze = options.freeze;
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const clone = options.clone;
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const loading = new Map();
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if (options.disable) {
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_.extend(load, { del }, options);
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return load;
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}
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function del() {
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const key = hash.apply(this, arguments);
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cache.del(key);
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}
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const result = function () {
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const args = vfs.apply(null, arguments);
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const parameters = args.slice(0, -1);
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const callback = args.slice(-1).pop();
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const self = this;
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var key;
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if (bypass && bypass.apply(self, parameters)) {
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return load.apply(self, args);
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}
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if (parameters.length === 0 && !hash) {
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//the load function only receives callback.
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key = '_';
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} else {
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key = hash.apply(self, parameters);
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}
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var fromCache = cache.get(key);
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if (fromCache) {
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if (clone) {
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return callback.apply(null, [null].concat(fromCache).map(_.cloneDeep));
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}
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return callback.apply(null, [null].concat(fromCache));
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}
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if (!loading.get(key)) {
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loading.set(key, []);
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load.apply(self, parameters.concat(function (err) {
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const args = vfs.apply(null, arguments);
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//we store the result only if the load didn't fail.
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if (!err) {
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const result = args.slice(1);
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if (freeze) {
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args.forEach(deepFreeze);
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}
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if (itemMaxAge) {
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cache.set(key, result, itemMaxAge.apply(self, parameters.concat(result)));
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} else {
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cache.set(key, result);
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}
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}
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//immediately call every other callback waiting
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const waiting = loading.get(key).concat(callback);
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loading.delete(key);
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waiting.forEach(function (callback) {
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if (clone) {
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return callback.apply(null, args.map(_.cloneDeep));
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}
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callback.apply(null, args);
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});
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/////////
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}));
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} else {
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loading.get(key).push(callback);
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}
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};
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result.keys = cache.keys.bind(cache);
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_.extend(result, { del }, options);
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return result;
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};
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module.exports.sync = function (options) {
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const cache = new LRU(_.pick(options, lru_params));
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const load = options.load;
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const hash = options.hash;
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const disable = options.disable;
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const bypass = options.bypass;
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const self = this;
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const itemMaxAge = options.itemMaxAge;
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if (disable) {
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return load;
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}
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const result = function () {
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var args = _.toArray(arguments);
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if (bypass && bypass.apply(self, arguments)) {
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return load.apply(self, arguments);
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}
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var key = hash.apply(self, args);
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var fromCache = cache.get(key);
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if (fromCache) {
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return fromCache;
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}
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const result = load.apply(self, args);
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if (itemMaxAge) {
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cache.set(key, result, itemMaxAge.apply(self, args.concat([ result ])));
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} else {
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cache.set(key, result);
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}
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return result;
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};
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result.keys = cache.keys.bind(cache);
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return result;
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};
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