109 lines
3.3 KiB
JavaScript
109 lines
3.3 KiB
JavaScript
/* Copyright 2017 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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var babel = require('plugin-babel');
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var cacheExpiration = 60 /* min */ * 60 * 1000;
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var dbVersion = 1;
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var dbName = 'babelcache';
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var dbCacheTable = 'translated';
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var dbPromise;
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function getDb() {
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if (!dbPromise) {
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dbPromise = new Promise(function (resolve, reject) {
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var request = indexedDB.open(dbName, dbVersion);
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request.onupgradeneeded = function() {
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var db = request.result;
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db.createObjectStore(dbCacheTable, {keyPath: 'address'});
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};
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request.onsuccess = function() {
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var db = request.result;
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resolve(db);
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};
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request.onerror = function () {
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reject(request.error);
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};
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});
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}
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return dbPromise;
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}
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function storeCache(address, hashCode, translated, format) {
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return getDb().then(function (db) {
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var tx = db.transaction(dbCacheTable, 'readwrite');
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var store = tx.objectStore(dbCacheTable);
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store.put({
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address: address,
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hashCode: hashCode,
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translated: translated,
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expires: Date.now() + cacheExpiration,
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format: format,
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});
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return new Promise(function (resolve, reject) {
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tx.oncomplete = function () {
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resolve();
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};
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});
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});
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}
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function loadCache(address, hashCode) {
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return getDb().then(function (db) {
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var tx = db.transaction(dbCacheTable, 'readonly');
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var store = tx.objectStore(dbCacheTable);
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var getAddress = store.get(address);
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return new Promise(function (resolve, reject) {
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tx.oncomplete = function () {
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var found = getAddress.result;
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var isValid = found && found.hashCode === hashCode &&
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Date.now() < found.expires;
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resolve(isValid ? {
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translated: found.translated,
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format: found.format,
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} : null);
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};
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});
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});
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}
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var encoder = new TextEncoder('utf-8');
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function sha256(str) {
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var buffer = encoder.encode(str);
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return crypto.subtle.digest('SHA-256', buffer).then(function (hash) {
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var data = new Int32Array(hash);
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return data[0].toString(36) + '-' + data[1].toString(36) + '-' +
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data[2].toString(36) + '-' + data[3].toString(36);
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});
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}
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exports.translate = function (load, opt) {
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var savedHashCode;
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return sha256(load.source).then(function (hashCode) {
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savedHashCode = hashCode;
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return loadCache(load.address, hashCode);
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}).then(function (cache) {
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if (cache) {
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load.metadata.format = cache.format;
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return cache.translated;
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}
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return babel.translate.call(this, load, opt).then(function(translated) {
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return storeCache(load.address, savedHashCode,
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translated, load.metadata.format).then(function () {
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return translated;
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});
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});
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}.bind(this));
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};
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