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			570 lines
		
	
	
	
		
			17 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
			
		
		
	
	
			570 lines
		
	
	
	
		
			17 KiB
		
	
	
	
		
			JavaScript
		
	
	
	
	
	
// -*- indent-tabs-mode: nil; js-indent-level: 2 -*-
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/* This Source Code Form is subject to the terms of the Mozilla Public
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 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
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 * You can obtain one at http://mozilla.org/MPL/2.0/. */
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// Constants for telemetry.
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const DOWNLOAD_SUCCESS = 0;
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const DOWNLOAD_ERROR_XHR = 1;
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const DOWNLOAD_ERROR_NO_DOC = 2;
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const PARSE_SUCCESS = 0;
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const PARSE_ERROR_TOO_MANY_ELEMENTS = 1;
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const PARSE_ERROR_WORKER = 2;
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const PARSE_ERROR_NO_ARTICLE = 3;
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// Class names to preserve in the readerized output. We preserve these class
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// names so that rules in aboutReader.css can match them.
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const CLASSES_TO_PRESERVE = [
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  "caption",
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  "emoji",
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  "hidden",
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  "invisible",
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  "sr-only",
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  "visually-hidden",
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  "visuallyhidden",
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  "wp-caption",
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  "wp-caption-text",
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  "wp-smiley",
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];
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import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
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const lazy = {};
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ChromeUtils.defineESModuleGetters(lazy, {
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  LanguageDetector:
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    "resource://gre/modules/translation/LanguageDetector.sys.mjs",
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  ReaderWorker: "resource://gre/modules/reader/ReaderWorker.sys.mjs",
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  Readerable: "resource://gre/modules/Readerable.sys.mjs",
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});
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const gIsFirefoxDesktop =
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  Services.appinfo.ID == "{ec8030f7-c20a-464f-9b0e-13a3a9e97384}";
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Services.telemetry.setEventRecordingEnabled("readermode", true);
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export var ReaderMode = {
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  DEBUG: 0,
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  // For time spent telemetry
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  enterTime: undefined,
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  leaveTime: undefined,
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  /**
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   * Enter the reader mode by going forward one step in history if applicable,
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   * if not, append the about:reader page in the history instead.
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   */
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  enterReaderMode(docShell, win) {
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    this.enterTime = Date.now();
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    Services.telemetry.recordEvent("readermode", "view", "on", null, {
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      subcategory: "feature",
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    });
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    let url = win.document.location.href;
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    let readerURL = "about:reader?url=" + encodeURIComponent(url);
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    if (!Services.appinfo.sessionHistoryInParent) {
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      let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
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      let sh = webNav.sessionHistory;
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      if (webNav.canGoForward) {
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        let forwardEntry = sh.legacySHistory.getEntryAtIndex(sh.index + 1);
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        let forwardURL = forwardEntry.URI.spec;
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        if (forwardURL && (forwardURL == readerURL || !readerURL)) {
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          webNav.goForward();
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          return;
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        }
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      }
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    }
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    // This could possibly move to the parent. See bug 1664982.
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    win.document.location = readerURL;
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  },
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  /**
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   * Exit the reader mode by going back one step in history if applicable,
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   * if not, append the original page in the history instead.
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   */
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  leaveReaderMode(docShell, win) {
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    this.leaveTime = Date.now();
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    // Measured in seconds (whole number)
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    let timeSpentInReaderMode = Math.floor(
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      (this.leaveTime - this.enterTime) / 1000
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    );
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    // Measured as percentage (whole number)
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    let scrollPosition = Math.floor(
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      ((win.scrollY + win.innerHeight) / win.document.body.clientHeight) * 100
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    );
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    Services.telemetry.recordEvent("readermode", "view", "off", null, {
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      subcategory: "feature",
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      reader_time: `${timeSpentInReaderMode}`,
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      scroll_position: `${scrollPosition}`,
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    });
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    let url = win.document.location.href;
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    let originalURL = this.getOriginalUrl(url);
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    let webNav = docShell.QueryInterface(Ci.nsIWebNavigation);
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    if (!Services.appinfo.sessionHistoryInParent) {
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      let sh = webNav.sessionHistory;
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      if (webNav.canGoBack) {
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        let prevEntry = sh.legacySHistory.getEntryAtIndex(sh.index - 1);
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        let prevURL = prevEntry.URI.spec;
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        if (prevURL && (prevURL == originalURL || !originalURL)) {
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          webNav.goBack();
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          return;
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        }
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      }
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    }
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    let referrerURI, principal;
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    try {
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      referrerURI = Services.io.newURI(url);
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      principal = Services.scriptSecurityManager.createContentPrincipal(
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        referrerURI,
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        win.document.nodePrincipal.originAttributes
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      );
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    } catch (e) {
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      console.error(e);
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      return;
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    }
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    let loadFlags = webNav.LOAD_FLAGS_DISALLOW_INHERIT_PRINCIPAL;
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    let ReferrerInfo = Components.Constructor(
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      "@mozilla.org/referrer-info;1",
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      "nsIReferrerInfo",
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      "init"
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    );
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    let loadURIOptions = {
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      triggeringPrincipal: principal,
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      loadFlags,
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      referrerInfo: new ReferrerInfo(
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        Ci.nsIReferrerInfo.EMPTY,
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        true,
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        referrerURI
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      ),
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    };
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    // This could possibly move to the parent. See bug 1664982.
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    webNav.fixupAndLoadURIString(originalURL, loadURIOptions);
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  },
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  /**
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   * Returns original URL from an about:reader URL.
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   *
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   * @param url An about:reader URL.
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   * @return The original URL for the article, or null if we did not find
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   *         a properly formatted about:reader URL.
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   */
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  getOriginalUrl(url) {
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    if (!url.startsWith("about:reader?")) {
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      return null;
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    }
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    let outerHash = "";
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    try {
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      let uriObj = Services.io.newURI(url);
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      url = uriObj.specIgnoringRef;
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      outerHash = uriObj.ref;
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    } catch (ex) {
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      /* ignore, use the raw string */
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    }
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    let searchParams = new URLSearchParams(
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      url.substring("about:reader?".length)
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    );
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    if (!searchParams.has("url")) {
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      return null;
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    }
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    let originalUrl = searchParams.get("url");
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    if (outerHash) {
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      try {
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        let uriObj = Services.io.newURI(originalUrl);
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        uriObj = Services.io.newURI("#" + outerHash, null, uriObj);
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        originalUrl = uriObj.spec;
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      } catch (ex) {}
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    }
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    return originalUrl;
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  },
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  getOriginalUrlObjectForDisplay(url) {
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    let originalUrl = this.getOriginalUrl(url);
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    if (originalUrl) {
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      let uriObj;
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      try {
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        uriObj = Services.uriFixup.getFixupURIInfo(originalUrl).preferredURI;
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      } catch (ex) {
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        return null;
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      }
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      try {
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        return Services.io.createExposableURI(uriObj);
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      } catch (ex) {
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        return null;
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      }
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    }
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    return null;
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  },
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  /**
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   * Gets an article from a loaded browser's document. This method will not attempt
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   * to parse certain URIs (e.g. about: URIs).
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   *
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   * @param doc A document to parse.
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   * @return {Promise}
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   * @resolves JS object representing the article, or null if no article is found.
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   */
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  parseDocument(doc) {
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    if (
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      !lazy.Readerable.shouldCheckUri(doc.documentURIObject) ||
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      !lazy.Readerable.shouldCheckUri(doc.baseURIObject, true)
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    ) {
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      this.log("Reader mode disabled for URI");
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      return null;
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    }
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    return this._readerParse(doc);
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  },
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  /**
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   * Downloads and parses a document from a URL.
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   *
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   * @param url URL to download and parse.
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   * @param attrs OriginAttributes to use for the request.
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   * @return {Promise}
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   * @resolves JS object representing the article, or null if no article is found.
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   */
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  async downloadAndParseDocument(url, attrs = {}, docContentType = "document") {
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    let result = await this._downloadDocument(url, attrs, docContentType);
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    if (!result?.doc) {
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      return null;
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    }
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    let { doc, newURL } = result;
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    if (
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      !lazy.Readerable.shouldCheckUri(doc.documentURIObject) ||
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      !lazy.Readerable.shouldCheckUri(doc.baseURIObject, true)
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    ) {
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      this.log("Reader mode disabled for URI");
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      return null;
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    }
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    let article = await this._readerParse(doc);
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    // If we have to redirect, reject to the caller with the parsed article,
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    // so we can update the URL before displaying it.
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    if (newURL) {
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      return Promise.reject({ newURL, article });
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    }
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    // Otherwise, we can just continue with the article.
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    return article;
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  },
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  _downloadDocument(url, attrs = {}, docContentType = "document") {
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    let uri;
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    try {
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      uri = Services.io.newURI(url);
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      if (!lazy.Readerable.shouldCheckUri(uri)) {
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        return null;
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      }
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    } catch (ex) {
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      console.error(
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        new Error(`Couldn't create URI from ${url} to download: ${ex}`)
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      );
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      return null;
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    }
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    let histogram = Services.telemetry.getHistogramById(
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      "READER_MODE_DOWNLOAD_RESULT"
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    );
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    try {
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      attrs.firstPartyDomain = Services.eTLD.getSchemelessSite(uri);
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    } catch (e) {
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      console.error("Failed to get first party domain for about:reader", e);
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    }
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    return new Promise((resolve, reject) => {
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      let xhr = new XMLHttpRequest({ mozAnon: false });
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      xhr.open("GET", url, true);
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      xhr.setOriginAttributes(attrs);
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      xhr.onerror = evt => reject(evt.error);
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      xhr.responseType = docContentType === "text/plain" ? "text" : "document";
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      xhr.onload = () => {
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        if (xhr.status !== 200) {
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          reject("Reader mode XHR failed with status: " + xhr.status);
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          histogram.add(DOWNLOAD_ERROR_XHR);
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          return;
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        }
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        let doc =
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          xhr.responseType === "text" ? xhr.responseText : xhr.responseXML;
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        if (!doc) {
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          reject("Reader mode XHR didn't return a document");
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          histogram.add(DOWNLOAD_ERROR_NO_DOC);
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          return;
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        }
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        let responseURL = xhr.responseURL;
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        let givenURL = url;
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        // Convert these to real URIs to make sure the escaping (or lack
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        // thereof) is identical:
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        try {
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          responseURL = Services.io.newURI(responseURL).specIgnoringRef;
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        } catch (ex) {
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          /* Ignore errors - we'll use what we had before */
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        }
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        try {
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          givenURL = Services.io.newURI(givenURL).specIgnoringRef;
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        } catch (ex) {
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          /* Ignore errors - we'll use what we had before */
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        }
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        if (xhr.responseType != "document") {
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          let initialText = doc;
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          let parser = new DOMParser();
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          doc = parser.parseFromString(`<pre></pre>`, "text/html");
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          doc.querySelector("pre").textContent = initialText;
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        }
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        // We treat redirects as download successes here:
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        histogram.add(DOWNLOAD_SUCCESS);
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        let result = { doc };
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        if (responseURL != givenURL) {
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          result.newURL = xhr.responseURL;
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        }
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        resolve(result);
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      };
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      xhr.send();
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    });
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  },
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  log(msg) {
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    if (this.DEBUG) {
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      dump("Reader: " + msg);
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    }
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  },
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  /**
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   * Attempts to parse a document into an article. Heavy lifting happens
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   * in Reader.worker.js.
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   *
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   * @param doc The document to parse.
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   * @return {Promise}
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   * @resolves JS object representing the article, or null if no article is found.
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   */
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  async _readerParse(doc) {
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    let histogram = Services.telemetry.getHistogramById(
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      "READER_MODE_PARSE_RESULT"
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    );
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    if (this.parseNodeLimit) {
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      let numTags = doc.getElementsByTagName("*").length;
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      if (numTags > this.parseNodeLimit) {
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        this.log(
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          "Aborting parse for " +
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            doc.baseURIObject.spec +
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            "; " +
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            numTags +
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            " elements found"
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        );
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        histogram.add(PARSE_ERROR_TOO_MANY_ELEMENTS);
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        return null;
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      }
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    }
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    // Fetch this here before we send `doc` off to the worker thread, as later on the
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    // document might be nuked but we will still want the URI.
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    let { documentURI } = doc;
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    let uriParam;
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    uriParam = {
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      spec: doc.baseURIObject.spec,
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      prePath: doc.baseURIObject.prePath,
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      scheme: doc.baseURIObject.scheme,
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      // Fallback
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      host: documentURI,
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      pathBase: documentURI,
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    };
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    // nsIURI.host throws an exception if a host doesn't exist.
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    try {
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      uriParam.host = doc.baseURIObject.host;
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      uriParam.pathBase = Services.io.newURI(".", null, doc.baseURIObject).spec;
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    } catch (ex) {
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      // Fall back to the initial values we assigned.
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      console.warn("Error accessing host name: ", ex);
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    }
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						|
    // convert text/plain document, if any, to XHTML format
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    if (this._isDocumentPlainText(doc)) {
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      doc = this._convertPlainTextDocument(doc);
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    }
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    let serializer = new XMLSerializer();
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    let serializedDoc = serializer.serializeToString(doc);
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    // Explicitly null out doc to make it clear it might not be available from this
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    // point on.
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    doc = null;
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    let options = {
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      classesToPreserve: CLASSES_TO_PRESERVE,
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    };
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    let article = null;
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    try {
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      article = await lazy.ReaderWorker.post("parseDocument", [
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        uriParam,
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        serializedDoc,
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        options,
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      ]);
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    } catch (e) {
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      console.error("Error in ReaderWorker: ", e);
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      histogram.add(PARSE_ERROR_WORKER);
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    }
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    if (!article) {
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      this.log("Worker did not return an article");
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      histogram.add(PARSE_ERROR_NO_ARTICLE);
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      return null;
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    }
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    // Readability returns a URI object based on the baseURI, but we only care
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    // about the original document's URL from now on. This also avoids spoofing
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    // attempts where the baseURI doesn't match the domain of the documentURI
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    article.url = documentURI;
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    delete article.uri;
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    let flags =
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      Ci.nsIDocumentEncoder.OutputSelectionOnly |
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      Ci.nsIDocumentEncoder.OutputAbsoluteLinks;
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    article.title = Cc["@mozilla.org/parserutils;1"]
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      .getService(Ci.nsIParserUtils)
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      .convertToPlainText(article.title, flags, 0);
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    if (gIsFirefoxDesktop) {
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      await this._assignLanguage(article);
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      this._maybeAssignTextDirection(article);
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    }
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    this._assignReadTime(article);
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    histogram.add(PARSE_SUCCESS);
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    return article;
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  },
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						|
  /**
 | 
						|
   * Sets a global language string value if the result is confident
 | 
						|
   *
 | 
						|
   * @return Promise
 | 
						|
   * @resolves when the language is detected
 | 
						|
   */
 | 
						|
  _assignLanguage(article) {
 | 
						|
    return lazy.LanguageDetector.detectLanguage(article.textContent).then(
 | 
						|
      result => {
 | 
						|
        article.language = result.confident ? result.language : null;
 | 
						|
      }
 | 
						|
    );
 | 
						|
  },
 | 
						|
 | 
						|
  _maybeAssignTextDirection(article) {
 | 
						|
    // TODO: Remove the hardcoded language codes below once bug 1320265 is resolved.
 | 
						|
    if (
 | 
						|
      !article.dir &&
 | 
						|
      ["ar", "fa", "he", "ug", "ur"].includes(article.language)
 | 
						|
    ) {
 | 
						|
      article.dir = "rtl";
 | 
						|
    }
 | 
						|
  },
 | 
						|
 | 
						|
  /**
 | 
						|
   * Assigns the estimated reading time range of the article to the article object.
 | 
						|
   *
 | 
						|
   * @param article the article object to assign the reading time estimate to.
 | 
						|
   */
 | 
						|
  _assignReadTime(article) {
 | 
						|
    let lang = article.language || "en";
 | 
						|
    const readingSpeed = this._getReadingSpeedForLanguage(lang);
 | 
						|
    const charactersPerMinuteLow = readingSpeed.cpm - readingSpeed.variance;
 | 
						|
    const charactersPerMinuteHigh = readingSpeed.cpm + readingSpeed.variance;
 | 
						|
    const length = article.length;
 | 
						|
 | 
						|
    article.readingTimeMinsSlow = Math.ceil(length / charactersPerMinuteLow);
 | 
						|
    article.readingTimeMinsFast = Math.ceil(length / charactersPerMinuteHigh);
 | 
						|
  },
 | 
						|
 | 
						|
  /**
 | 
						|
   * Returns the reading speed of a selection of languages with likely variance.
 | 
						|
   *
 | 
						|
   * Reading speed estimated from a study done on reading speeds in various languages.
 | 
						|
   * study can be found here: http://iovs.arvojournals.org/article.aspx?articleid=2166061
 | 
						|
   *
 | 
						|
   * @return object with characters per minute and variance. Defaults to English
 | 
						|
   *         if no suitable language is found in the collection.
 | 
						|
   */
 | 
						|
  _getReadingSpeedForLanguage(lang) {
 | 
						|
    const readingSpeed = new Map([
 | 
						|
      ["en", { cpm: 987, variance: 118 }],
 | 
						|
      ["ar", { cpm: 612, variance: 88 }],
 | 
						|
      ["de", { cpm: 920, variance: 86 }],
 | 
						|
      ["es", { cpm: 1025, variance: 127 }],
 | 
						|
      ["fi", { cpm: 1078, variance: 121 }],
 | 
						|
      ["fr", { cpm: 998, variance: 126 }],
 | 
						|
      ["he", { cpm: 833, variance: 130 }],
 | 
						|
      ["it", { cpm: 950, variance: 140 }],
 | 
						|
      ["jw", { cpm: 357, variance: 56 }],
 | 
						|
      ["nl", { cpm: 978, variance: 143 }],
 | 
						|
      ["pl", { cpm: 916, variance: 126 }],
 | 
						|
      ["pt", { cpm: 913, variance: 145 }],
 | 
						|
      ["ru", { cpm: 986, variance: 175 }],
 | 
						|
      ["sk", { cpm: 885, variance: 145 }],
 | 
						|
      ["sv", { cpm: 917, variance: 156 }],
 | 
						|
      ["tr", { cpm: 1054, variance: 156 }],
 | 
						|
      ["zh", { cpm: 255, variance: 29 }],
 | 
						|
    ]);
 | 
						|
 | 
						|
    return readingSpeed.get(lang) || readingSpeed.get("en");
 | 
						|
  },
 | 
						|
  /**
 | 
						|
   *
 | 
						|
   * Check if the document to be parsed is text document.
 | 
						|
   * @param doc the doc object to be parsed.
 | 
						|
   * @return boolean
 | 
						|
   *
 | 
						|
   */
 | 
						|
  _isDocumentPlainText(doc) {
 | 
						|
    return doc.contentType == "text/plain";
 | 
						|
  },
 | 
						|
  /**
 | 
						|
   *
 | 
						|
   * The document to be parsed is text document and is converted to HTML format.
 | 
						|
   * @param doc the doc object to be parsed.
 | 
						|
   * @return doc
 | 
						|
   *
 | 
						|
   */
 | 
						|
  _convertPlainTextDocument(doc) {
 | 
						|
    let preTag = doc.querySelector("pre");
 | 
						|
    let docFrag = doc.createDocumentFragment();
 | 
						|
    let content = preTag.textContent;
 | 
						|
    let paragraphs = content.split(/\r?\n\r?\n/);
 | 
						|
    for (let para of paragraphs) {
 | 
						|
      let pElem = doc.createElement("p");
 | 
						|
      let lines = para.split(/\n/);
 | 
						|
      for (let line of lines) {
 | 
						|
        pElem.append(line);
 | 
						|
        let brElem = doc.createElement("br");
 | 
						|
        pElem.append(brElem);
 | 
						|
      }
 | 
						|
      docFrag.append(pElem);
 | 
						|
    }
 | 
						|
    // Clone the document to avoid the original document being affected
 | 
						|
    // (which shows up when exiting reader mode again).
 | 
						|
    let clone = doc.documentElement.cloneNode(true);
 | 
						|
    clone.querySelector("pre").replaceWith(docFrag);
 | 
						|
    return clone;
 | 
						|
  },
 | 
						|
};
 | 
						|
 | 
						|
XPCOMUtils.defineLazyPreferenceGetter(
 | 
						|
  ReaderMode,
 | 
						|
  "maxElemsToParse",
 | 
						|
  "reader.parse-node-limit",
 | 
						|
  0
 | 
						|
);
 |