polymer-analyzer
Version:
Static analysis for Web Components
112 lines • 4.41 kB
JavaScript
;
/**
* @license
* Copyright (c) 2016 The Polymer Project Authors. All rights reserved.
* This code may only be used under the BSD style license found at
* http://polymer.github.io/LICENSE.txt
* The complete set of authors may be found at
* http://polymer.github.io/AUTHORS.txt
* The complete set of contributors may be found at
* http://polymer.github.io/CONTRIBUTORS.txt
* Code distributed by Google as part of the polymer project is also
* subject to an additional IP rights grant found at
* http://polymer.github.io/PATENTS.txt
*/
var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
return new (P || (P = Promise))(function (resolve, reject) {
function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
step((generator = generator.apply(thisArg, _arguments || [])).next());
});
};
Object.defineProperty(exports, "__esModule", { value: true });
const cancel_token_1 = require("cancel-token");
const cancel_token_2 = require("./cancel-token");
/**
* A map from keys to promises of values. Used for caching asynchronous work.
*/
class AsyncWorkCache {
constructor(from) {
if (from) {
this._keyToResultMap = new Map(from._keyToResultMap);
}
else {
this._keyToResultMap = new Map();
}
}
/**
* If work has already begun to compute the given key, return a promise for
* the result of that work.
*
* If not, compute it with the given function.
*
* This method ensures that, in the absence of cancellations, we will only try
* to compute the value for `key` once, no matter how often or with what
* timing getOrCompute is called, even recursively.
*
* This API is safe for multiple, independently cancellable callers. So long
* as the given cancelToken is not cancelled, this function will not reject
* with a Cancel exception.
*/
getOrCompute(key, compute, cancelToken = cancel_token_2.neverCancels) {
return __awaiter(this, void 0, void 0, function* () {
cancelToken.throwIfRequested();
while (true) {
try {
const result = yield this._getOrCompute(key, compute);
cancelToken.throwIfRequested();
return result;
}
catch (err) {
cancelToken.throwIfRequested();
if (cancel_token_1.isCancel(err)) {
// Ok, whoever was working on computing `key` was cancelled, but it
// wasn't us because we're not cancelled. Let's try again!.
continue;
}
throw err;
}
}
});
}
_getOrCompute(key, compute) {
return __awaiter(this, void 0, void 0, function* () {
const cachedResult = this._keyToResultMap.get(key);
if (cachedResult) {
return cachedResult;
}
const promise = (() => __awaiter(this, void 0, void 0, function* () {
// Make sure we wait and return a Promise before doing any work, so that
// the Promise is cached before control flow enters compute().
yield Promise.resolve();
return compute();
}))();
this._keyToResultMap.set(key, promise);
try {
yield promise;
}
catch (err) {
if (cancel_token_1.isCancel(err)) {
this._keyToResultMap.delete(key);
}
throw err;
}
return promise;
});
}
delete(key) {
this._keyToResultMap.delete(key);
}
clear() {
this._keyToResultMap.clear();
}
set(key, value) {
this._keyToResultMap.set(key, Promise.resolve(value));
}
has(key) {
return this._keyToResultMap.has(key);
}
}
exports.AsyncWorkCache = AsyncWorkCache;
//# sourceMappingURL=async-work-cache.js.map