mirror of https://github.com/gorhill/uBlock.git
privacy exposure reduction: local mirroring of CDN resources
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gorhill
parent
5b984855d0
commit
a3bd6ec179
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/*******************************************************************************
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µBlock - a Chromium browser extension to block requests.
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Copyright (C) 2014 Raymond Hill
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see {http://www.gnu.org/licenses/}.
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Home: https://github.com/gorhill/uBlock
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*/
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/* global chrome, YaMD5, µBlock */
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/******************************************************************************/
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// Low-level asset files manager
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µBlock.mirrors = (function() {
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/******************************************************************************/
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var exports = {
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bytesInUse: 0,
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hitCount: 0
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};
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/******************************************************************************/
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var nullFunc = function() {};
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var mirrorCandidates = {
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'ajax.googleapis.com': /^ajax\.googleapis\.com\/ajax\/libs\//,
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'fonts.googleapis.com': /^fonts\.googleapis\.com/,
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'fonts.gstatic.com': /^fonts\.gstatic\.com/,
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'cdnjs.cloudflare.com': /^cdnjs\.cloudflare\.com\/ajax\/libs\//,
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'code.jquery.com': /^code\.jquery\.com/,
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's0.2mdn.net': /(2mdn\.net\/instream\/html5\/ima3\.js)/,
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'connect.facebook.net': /(connect\.facebook\.net\/[^\/]+\/all\.js)/,
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'www.googletagservices.com': /(www\.googletagservices\.com\/tag\/js\/gpt\.js)/
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};
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var magicId = 'rmwwgwkzcgfv';
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var bytesInUseMax = 20 * 1024 * 1024;
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var ttl = 30 * 24 * 60 * 60 * 1000;
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var metadataPersistTimer = null;
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var metadata = {
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magicId: magicId,
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urlKeyToHashMap: {}
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};
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// Hash to content map
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var hashToDataUrlMap = {};
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var loaded = false;
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/******************************************************************************/
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var MetadataEntry = function(hash) {
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this.accessTime = Date.now();
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this.hash = hash;
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};
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var ContentEntry = function(dataURL) {
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this.createTime = Date.now();
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this.dataURL = dataURL;
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};
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/******************************************************************************/
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var getTextFileFromURL = function(url, onLoad, onError) {
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if ( typeof onLoad !== 'function' ) {
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onLoad = nullFunc;
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}
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if ( typeof onError !== 'function' ) {
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onError = onLoad;
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}
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var xhr = new XMLHttpRequest();
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xhr.responseType = 'text';
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xhr.timeout = 10000;
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xhr.onload = onLoad;
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xhr.onerror = onError;
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xhr.ontimeout = onError;
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xhr.open('get', url, true);
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xhr.send();
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};
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/******************************************************************************/
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// Extract a `key` from a URL.
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var toUrlKey = function(url) {
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if ( url.slice(0, 4) !== 'http' ) {
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return '';
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}
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var pos = url.indexOf('://');
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if ( pos === -1 ) {
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return '';
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}
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url = url.slice(pos + 3);
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pos = url.indexOf('/');
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if ( pos === -1 ) {
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return -1;
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}
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var re = mirrorCandidates[url.slice(0, pos)];
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if ( typeof re !== 'object' || typeof re.test !== 'function' ) {
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return '';
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}
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var matches = re.exec(url);
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if ( matches === null ) {
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return '';
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}
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return matches.length === 1 ? url : matches[1];
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};
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/******************************************************************************/
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// Ref: http://www.iana.org/assignments/media-types/media-types.xhtml
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var normalizeContentType = function(ctin) {
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var ctout;
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var encoding;
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var pos = ctin.indexOf(';');
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if ( pos === -1 ) {
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ctout = ctin.trim();
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encoding = '';
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} else {
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ctout = ctin.slice(0, pos).trim();
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encoding = ctin.slice(pos + 1).trim();
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}
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if ( encoding !== '' ) {
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ctout += ';' + encoding;
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}
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return ctout;
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};
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/******************************************************************************/
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var metadataExists = function(urlKey) {
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return typeof urlKey === 'string' && metadata.urlKeyToHashMap.hasOwnProperty(urlKey);
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};
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/******************************************************************************/
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var contentExists = function(hash) {
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return typeof hash === 'string' && hashToDataUrlMap.hasOwnProperty(hash);
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};
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/******************************************************************************/
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var updateMetadata = function() {
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metadataPersistTimer = null;
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chrome.storage.local.set({ 'mirrors_metadata': metadata });
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};
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/******************************************************************************/
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var updateMetadataAsync = function(urlKey, hash) {
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var doesExist = metadataExists(urlKey);
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if ( doesExist ) {
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metadata.urlKeyToHashMap[urlKey].accessTime = Date.now();
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if ( metadataPersistTimer === null ) {
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setTimeout(updateMetadata, 60 * 1000);
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}
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return;
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}
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metadata.urlKeyToHashMap[urlKey] = new MetadataEntry(hash);
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if ( metadataPersistTimer !== null ) {
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clearTimeout(metadataPersistTimer);
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}
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updateMetadata();
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};
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/******************************************************************************/
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var updateContent = function(hash, dataURL) {
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if ( contentExists(hash) !== false ) {
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return;
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}
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var contentEntry = hashToDataUrlMap[hash] = new ContentEntry(dataURL);
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exports.bytesInUse += dataURL.length;
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var key = 'mirrors_item_' + hash;
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var bin = {};
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bin[key] = contentEntry;
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chrome.storage.local.set(bin);
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};
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/******************************************************************************/
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var cacheAsset = function(url) {
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var urlKey = toUrlKey(url);
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if ( metadataExists(urlKey) ) {
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return;
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}
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var onRemoteAssetLoaded = function() {
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this.onload = this.onerror = null;
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if ( this.status !== 200 ) {
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return;
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}
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var contentType = normalizeContentType(this.getResponseHeader('Content-Type'));
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if ( contentType === '' ) {
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//console.debug('mirrors.cacheAsset(): no good content type available');
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return;
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}
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var yamd5 = new YaMD5();
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yamd5.appendAsciiStr(contentType);
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yamd5.appendAsciiStr(this.response);
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var hash = yamd5.end();
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updateMetadataAsync(urlKey, hash);
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if ( contentExists(hash) ) {
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//console.debug('mirrors.cacheAsset(): reusing existing content for "%s"', urlKey);
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return;
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}
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//console.debug('mirrors.cacheAsset(): caching new content for "%s"', urlKey);
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// Keep original encoding if there was one, otherwise use base64 --
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// as the result is somewhat more compact I believe
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var dataUrl = contentType.indexOf(';') !== -1 ?
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'data:' + contentType + ',' + encodeURIComponent(this.responseText) :
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'data:' + contentType + ';base64,' + btoa(this.response);
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updateContent(hash, dataUrl);
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};
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var onRemoteAssetError = function() {
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this.onload = this.onerror = null;
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};
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getTextFileFromURL(
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url,
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onRemoteAssetLoaded,
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onRemoteAssetError
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);
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};
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/******************************************************************************/
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var toURL = function(url, cache) {
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var urlKey = toUrlKey(url);
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if ( urlKey === '' ) {
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return '';
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}
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if ( metadataExists(urlKey) === false ) {
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if ( cache === true ) {
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cacheAsset(url);
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}
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return '';
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}
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var metadataEntry = metadata.urlKeyToHashMap[urlKey];
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if ( contentExists(metadataEntry.hash) === false ) {
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return '';
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}
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var contentEntry = hashToDataUrlMap[metadataEntry.hash];
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updateMetadataAsync(urlKey);
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exports.hitCount += 1;
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return contentEntry.dataURL;
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};
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/******************************************************************************/
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var load = function() {
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loaded = true;
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var loadContent = function(hash) {
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var key = 'mirrors_item_' + hash;
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var onContentReady = function(bin) {
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if ( chrome.runtime.lastError ) {
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return;
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}
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var contentEntry = bin[key];
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hashToDataUrlMap[hash] = contentEntry;
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exports.bytesInUse += contentEntry.dataURL.length;
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};
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var bin = {};
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bin[key] = '';
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chrome.storage.local.get(bin, onContentReady);
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};
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var onMetadataReady = function(bin) {
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if ( chrome.runtime.lastError ) {
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return;
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}
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metadata = bin.mirrors_metadata;
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var hemap = metadata.urlKeyToHashMap;
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for ( var urlKey in hemap ) {
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if ( hemap.hasOwnProperty(urlKey) === false ) {
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continue;
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}
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loadContent(hemap[urlKey].hash);
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}
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};
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chrome.storage.local.get({ 'mirrors_metadata' : metadata }, onMetadataReady);
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};
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/******************************************************************************/
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var unload = function() {
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if ( metadataPersistTimer !== null ) {
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updateMetadata();
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}
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metadata.urlKeyToHashMap = {};
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hashToDataUrlMap = {};
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exports.bytesInUse = 0;
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exports.hitCount = 0;
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loaded = false;
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};
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/******************************************************************************/
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exports.toggle = function(on) {
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if ( on && loaded !== true ) {
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load();
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} else if ( on !== true && loaded ) {
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unload();
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}
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};
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/******************************************************************************/
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// Export API
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exports.toURL = toURL;
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return exports;
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/******************************************************************************/
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})();
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/******************************************************************************/
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