Personal Blocklist Fix

// Copyright 2011 Google Inc. All Rights Reserved.

/**
 * @fileoverview Applies blocklist features to Google search result pages.
 * @author manuelh@google.com (Manuel Holtz)
 */

/**
 * Namespace for the content script functions for Google search result pages.
 * @const
 */
blocklist.serp = {};

/**
 * Class of the search results on Google SERP.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_CLASS = 'g';

/**
 * Class to add to a search result after it was processed by the extension.
 * @type {string}
 */
blocklist.serp.PERSONAL_BLOCKLIST_CLASS = 'pb';

/**
 * Class of blocked search results.
 * @type {string}
 */
blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS = 'blocked';

/**
 * Class of blocked search results that were requested to be shown.
 * @type {string}
 */
blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS = 'blockedVisible';

/**
 * Class of a element that holds block/unblock links.
 * @type {string}
 */
blocklist.serp.BLOCK_LINK_CLASS = 'fl';

/**
 * Class of the search result bodies on Google SERP.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_BODY_CLASS = 's';

/**
 * Class of the search results lower links on Google SERP.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_LOWER_LINKS_CLASS = 'gl';

/**
 * Class that contains the cite tag on Google SERP.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_CITE_DIV_CLASS = 'kv';

/**
 * Class of the short (snippet-less) search results links on Google SERP.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_SHORT_LINKS_CLASS = 'vshid';

/**
 * Class of lower links span for definition-like results (e.g. query "viagra").
 * @type {string}
 */
blocklist.serp.DEFINITION_RESULT_LOWER_LINKS_CLASS = 'a';

/**
 * Class of book search result table cell, used to identify book search results.
 * @type {string}
 */
blocklist.serp.BOOK_SEARCH_RESULT_CLASS = 'bkst';

/**
 * Class of the search results block div.
 * @type {string}
 */
blocklist.serp.SEARCH_RESULT_BLOCK_CLASS = 'ires';

/**
 * Id of the div that displays the result removal notification.
 * @type {string}
 */
blocklist.serp.NOTIFICATION_DIV_ID = 'blocklistNotification';

/**
 * Class name that identifies gws-side block links.
 * @type {string}
 */
blocklist.serp.GWS_BLOCK_LINK_CLASS = 'kob';

/**
 * Class name that identifies showed gws-side block links.
 * @type {string}
 */
blocklist.serp.SHOWED_GWS_BLOCK_LINK_CLASS = 'kobb';

/**
 * The interval between attempts to apply blocklist feats to SERP, in millisecs.
 * @type {number}
 */
blocklist.serp.REPEAT_INTERVAL_IN_MS = 500;

// TODO(manuelh): Use CSS file for styles instead.
/**
 * Style of the notification for removed search results.
 * @type {string}
 */
blocklist.serp.NOTIFICATION_STYLE =
    'font-style:italic;margin-top:1em;margin-bottom:1em;';

/**
 * Style for block links. Prevents the word "Block" from appearing on a separate
 * line to the domain being blocked.
 */
blocklist.serp.BLOCK_LINK_STYLE = 'white-space:nowrap;';

/**
 * Type of refresh request.
 * @type {string}
 */
blocklist.serp.REFRESH_REQUEST = 'refresh';

/**
 * Style of blocked search results that are shown on request.
 * @type {string}
 */
blocklist.serp.BLOCKED_VISIBLE_STYLE = 'display:block;background-color:#FFD2D2';

/**
 * A regular expression to deal with redirections through Google services,
 * e.g. for translated results like
 * http://translate.google.com/translate?u=http://example.com
 * @type {RegExp}
 */
blocklist.serp.REDIRECT_REGEX = new RegExp(
    '^(https?://[a-z.]+[.]?google([.][a-z]{2,4}){1,2})?/' +
    '[a-z_-]*[?]((img)?u|.*&(img)?u)(rl)?=([^&]*[.][^&]*).*$');

/**
 * A regular expression to check if personalized web search is disabled in url.
 * @type {RegExp}
 */
blocklist.serp.PWS_REGEX = new RegExp('(&|[?])pws=0');

/**
 * Matches the kEI javascript property defined in the header of the Google SRP.
 * @type {RegExp}
 */
blocklist.serp.EVENT_ID_REGEX = new RegExp('kEI\\:"([^"]+)"');

/**
 * The blocklisted patterns. Call blocklist.serp.refreshBlocklist to populate.
 * @type {Array.<string>}
 */
blocklist.serp.blocklist = [];

/**
 * The event id of the search result page.
 * @type {string}
 */
blocklist.serp.eventId = '';

/**
 * Whether the current search result page is https page.
 * The extension will not send info back to google via gen204 request if user is
 * under https page.
 * @type {bool}
 */
blocklist.serp.isHttps = false;

/**
 * Whether the search result alterations (block links etc) need to be reapplied.
 * Used by blocklist.serp.modifySearchResults_ that constitutes what happens in
 * the main process loop of the extension. This variable primarily helps with
 * efficiency, because it avoids unnecessary repetitions.
 *
 * @type {bool}
 */
blocklist.serp.needsRefresh = false;

/**
 * Creates a DOM element containing a "block domain" or "unblock domain" link.
 * @param {function} handler The function to bind to a click.
 * @param {string} pattern The domain pattern to send to the handler on click.
 * @param {string} className Name of the message string and span class.
 * @return {Element} A div element with the block link.
 * @private
 */
blocklist.serp.createLink_ = function(handler, pattern, className) {
  var blockLink = document.createElement('a');
  blockLink.setAttribute('dir', chrome.i18n.getMessage('textDirection'));
  blockLink.className = blocklist.serp.BLOCK_LINK_CLASS;
  blockLink.setAttribute('style', blocklist.serp.BLOCK_LINK_STYLE);
  blockLink.href = 'javascript:;';  // Do nothing, no refresh.
  blockLink.addEventListener(
      'click', function() { handler(pattern) }, false);

  // Separate spans to avoid mixing latin chars with Arabic/Hebrew.
  var prefixSpan = document.createElement('span');
  prefixSpan.appendChild(document.createTextNode(
       chrome.i18n.getMessage(className + 'Prefix')));
  var patternSpan = document.createElement('span');
  patternSpan.appendChild(document.createTextNode(pattern));
  var suffixSpan = document.createElement('span');
  suffixSpan.appendChild(document.createTextNode(
      chrome.i18n.getMessage(className + 'Suffix')));

  blockLink.appendChild(prefixSpan);
  blockLink.appendChild(patternSpan);
  blockLink.appendChild(suffixSpan);

  var blockLinkDiv = document.createElement('div');
  blockLinkDiv.className = className;
  blockLinkDiv.appendChild(blockLink);
  return blockLinkDiv;
};

/**
 * Adds a block or unblock link to a search result.
 * @param {Element} searchResult Search result list element, including children.
 * @param {Object} linkDiv Div element with the link to add.
 */
blocklist.serp.addLink = function(searchResult, linkDiv) {
  var regularResultSpan = searchResult.querySelector(
      'div.' + blocklist.serp.SEARCH_RESULT_CITE_DIV_CLASS);
  var definitionResultSpan = searchResult.querySelector(
      'span.' + blocklist.serp.DEFINITION_RESULT_LOWER_LINKS_CLASS);
  var shortResultDiv = searchResult.querySelector(
      'div.' + blocklist.serp.SEARCH_RESULT_BODY_CLASS +
      ' span.' + blocklist.serp.SEARCH_RESULT_SHORT_LINKS_CLASS);
  if (regularResultSpan !== null) {
    regularResultSpan.parentNode.appendChild(linkDiv);
  } else if (definitionResultSpan !== null) {
    definitionResultSpan.parentNode.parentNode.appendChild(linkDiv);
  } else if (shortResultDiv !== null) {
    shortResultDiv.parentNode.parentNode.appendChild(linkDiv);
  }
};

/**
 * Adds a DOM element containing a notification for removed results.
 * @private
 */
blocklist.serp.addBlockListNotification_ = function() {
  var showBlockedLink = document.createElement('a');
  showBlockedLink.href = 'javascript:;';  // Do nothing, no refresh.
  showBlockedLink.appendChild(document.createTextNode(
      chrome.i18n.getMessage('showBlockedLink')));
  showBlockedLink.addEventListener(
      'click', function() { blocklist.serp.showBlockedResults_() }, false);

  var blocklistNotification = document.createElement('div');
  blocklistNotification.id = blocklist.serp.NOTIFICATION_DIV_ID;
  blocklistNotification.setAttribute(
      'dir', chrome.i18n.getMessage('textDirection'));
  blocklistNotification.appendChild(document.createTextNode(
      chrome.i18n.getMessage('blocklistNotification') + ' ('));
  blocklistNotification.appendChild(showBlockedLink);
  blocklistNotification.appendChild(document.createTextNode(').'));
  blocklistNotification.setAttribute(
      'style', blocklist.serp.NOTIFICATION_STYLE);

  searchResultBlock = document.querySelector(
      'div#' + blocklist.serp.SEARCH_RESULT_BLOCK_CLASS);
  searchResultBlock.parentNode.insertBefore(blocklistNotification,
                                            searchResultBlock.nextSibling);
};

/**
 * Makes blocked search results visible again.
 * @private
 */
blocklist.serp.showBlockedResults_ = function() {
  var blockedResultList = document.querySelectorAll(
      'div.' + blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
  for (var i = 0; i < blockedResultList.length; i++) {
    blockedResultList[i].setAttribute('style',
                                     blocklist.serp.BLOCKED_VISIBLE_STYLE);
    blockedResultList[i].className = blocklist.common.removeClass(
        blockedResultList[i].className,
        blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
    blockedResultList[i].className = blocklist.common.addClass(
        blockedResultList[i].className,
        blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS);
  }
  blocklist.serp.needsRefresh = true;
};

/**
 * Adds a pattern to the blocklist.
 * @param {string} pattern The pattern to blocklist.
 * @private
 */
blocklist.serp.addBlocklistPattern_ = function(pattern) {
  chrome.extension.sendRequest({type: blocklist.common.ADDTOBLOCKLIST,
                                pattern: pattern,
                                ei: blocklist.serp.eventId,
                                enc: blocklist.serp.isHttps},
                               blocklist.serp.handleAddToBlocklistResponse);
};

/**
 * Removes a pattern from the blocklist.
 * @param {string} pattern The pattern to remove from the blocklist.
 * @private
 */
blocklist.serp.removeBlocklistPattern_ = function(pattern) {
  chrome.extension.sendRequest(
      {type: blocklist.common.DELETEFROMBLOCKLIST,
       pattern: pattern,
       ei: blocklist.serp.eventId,
       enc: blocklist.serp.isHttps},
      blocklist.serp.handleDeleteFromBlocklistResponse);
};

/**
 * Parses the domain out of a Google search result page.
 * @param {Object} searchResult Search result list element (including children).
 * @return {string} A domain if found; or an empty string.
 * @private
 */
blocklist.serp.parseDomainFromSearchResult_ = function(searchResult) {
  var searchResultAnchor = searchResult.querySelector('h3 > a');
  if (searchResultAnchor === null) {
    return '';
  }
  var url = searchResultAnchor.getAttribute('href');
  // Sometimes, the link is an intermediate step through another google service,
  // for example Google Translate. This regex parses the target url, so that we
  // don't block translate.google.com instead of the target host.
  url = url.replace(blocklist.serp.REDIRECT_REGEX, '$7');
  // Identify domain by stripping protocol and path.
  return url.replace(blocklist.common.HOST_REGEX, '$2');
};

/**
 * Determines if and in which way a result result needs to be modified.
 * @param {Element} searchResult Search result list element, including children.
 * @private
 */
blocklist.serp.alterSearchResultNode_ = function(searchResult) {
  var host = blocklist.serp.parseDomainFromSearchResult_(searchResult);
  if (!host) {
    return;
  }

  // Skip if there is already a gws-side block link, this is a book search
  // vertical results, or an internal url that was not resolved.
  if (searchResult.querySelector(
          '.' + blocklist.serp.GWS_BLOCK_LINK_CLASS) !== null ||
      searchResult.querySelector(
          'td.' + blocklist.serp.BOOK_SEARCH_RESULT_CLASS) !== null ||
      host[0] == '/') {
    // Mark search result as processed.
    searchResult.className = blocklist.common.addClass(
        searchResult.className, blocklist.serp.PERSONAL_BLOCKLIST_CLASS);
    return;
  }

  // Any currently appended block/unblock links need to be replaced.
  blockLink = searchResult.querySelector('div.blockLink');
  unblockLink = searchResult.querySelector('div.unblockLink');

  // Two main cases where we need to take action:
  // 1. search result should have a block link and doesn't have one already.
  // 2. search result should have an unblock link and doesn't have one already.
  if (blockLink === null &&
      (blocklist.common.hasClass(
           searchResult.className,
           blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS) == false)) {
    var blockLinkDiv = blocklist.serp.createLink_(
        blocklist.serp.addBlocklistPattern_, host, 'blockLink');

    // Replace existing link, or append.
    if (unblockLink !== null) {
      unblockLink.parentNode.replaceChild(blockLinkDiv, unblockLink);
    } else {
      blocklist.serp.addLink(searchResult, blockLinkDiv);
    }
  } else if (unblockLink === null &&
             blocklist.common.hasClass(
                 searchResult.className,
                 blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS)) {
    // Use the pattern that caused the block, which might differ from host.
    var blockPattern = blocklist.serp.findBlockPatternForHost_(host);
    if (!blockPattern) {
      return;
    }
    var unblockLinkDiv = blocklist.serp.createLink_(
        blocklist.serp.removeBlocklistPattern_, blockPattern, 'unblockLink');

    // Replace existing link, or append.
    if (blockLink !== null) {
      blockLink.parentNode.replaceChild(unblockLinkDiv, blockLink);
    } else {
      blocklist.serp.addLink(searchResult, unblockLinkDiv);
    }
  }
  // Mark search result as processed.
  searchResult.className = blocklist.common.addClass(
      searchResult.className, blocklist.serp.PERSONAL_BLOCKLIST_CLASS);
};

/**
 * Removes a search result from the page.
 * @param {Object} searchResult Search result list element (including children).
 */
blocklist.serp.hideSearchResult = function(searchResult) {
  searchResult.setAttribute('style', 'display:none;');
  searchResult.className = blocklist.common.addClass(
      searchResult.className, blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
};

/**
 * Return a list of subdomains. for example, a.d.c.d will return
 * c.d, d.c.d and a.b.c.d
 * @param {string} pattern The domains pattern to extract subdomains.
 * @return {Array.<string>} Suddomain list.
 * @private
 */
blocklist.serp.extractSubDomains_ = function(pattern) {
  var subdomains = [];
  var parts = pattern.split('.');
  for (var i = parts.length - 2; i >= 0; --i) {
    subdomains.push(parts.slice(i).join('.'));
  }
  return subdomains;
};

/**
 * Checks a hostname against the blocklist patterns.
 * @param {string} hostName Host of a search result link.
 * @return {string} A blocklist pattern that matched the host (or empty string).
 * @private
 */
blocklist.serp.findBlockPatternForHost_ = function(hostName) {
  var matchedPattern = '';
  // Match each level of subdomains against the blocklist. For example, if
  // a.com is blocked, b.a.com should be hidden from search result.
  var subdomains = blocklist.serp.extractSubDomains_(hostName);
  for (var j = 0; j < subdomains.length; ++j) {
    if (blocklist.serp.blocklist.indexOf(subdomains[j]) != -1) {
      matchedPattern = subdomains[j];
      break;
    }
  }
  return matchedPattern;
};

/**
 * Removes all search results that match the blocklist.
 */
blocklist.serp.hideSearchResults = function() {
  var searchResultList = document.querySelectorAll(
      'div.' + blocklist.serp.SEARCH_RESULT_CLASS);
  for (var i = 0; i < searchResultList.length; i++) {
    var searchResult = searchResultList[i];
    var matchedPattern = blocklist.serp.findBlockPatternForHost_(
        blocklist.serp.parseDomainFromSearchResult_(searchResult));

    if (matchedPattern &&
        ((blocklist.common.hasClass(
             searchResult.className,
             blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS) == false) &&
         (blocklist.common.hasClass(
             searchResult.className,
             blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS) == false))) {
      if (blocklist.common.hasClass(searchResult.parentNode.className,
             blocklist.serp.SHOWED_GWS_BLOCK_LINK_CLASS) == true) {
        searchResult.setAttribute('style',
                                          blocklist.serp.BLOCKED_VISIBLE_STYLE);
        searchResult.className = blocklist.common.removeClass(
            searchResult.className,
            blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
        searchResult.className = blocklist.common.addClass(
            searchResult.className,
            blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS);
      } else {
        blocklist.serp.hideSearchResult(searchResult);
      }
    }

    if (!matchedPattern) {
      if (blocklist.common.hasClass(
              searchResult.className,
              blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS) ||
          blocklist.common.hasClass(
              searchResult.className,
              blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS)) {
        searchResult.className = blocklist.common.removeClass(
            searchResult.className,
            blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS);
        searchResult.className = blocklist.common.removeClass(
            searchResult.className,
            blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
        searchResult.setAttribute('style', 'background-color:inherit;');
      }
    }
  }
};

/**
 * Iterates through search results, adding links and applying blocklist filter.
 * @private
 */
blocklist.serp.modifySearchResults_ = function() {
  // Skip if personalized web search was explicitly disabled (&pws=0).
  if (blocklist.serp.IsPwsDisabled_() == true) {
    return;
  }
  // Apply blocklist filter.
  if (blocklist.serp.blocklist.length > 0 || blocklist.serp.needsRefresh) {
    blocklist.serp.hideSearchResults();
  }
  var searchResultList = document.querySelectorAll(
      'div.' + blocklist.serp.SEARCH_RESULT_CLASS);
  var processedSearchResultList = document.querySelectorAll(
      'li.' + blocklist.serp.PERSONAL_BLOCKLIST_CLASS);

  // Add blocklist links to search results until all have been processed.
  if (blocklist.serp.needsRefresh ||
      processedSearchResultList.length < searchResultList.length) {
    for (var i = 0; i < searchResultList.length; i++) {
      blocklist.serp.alterSearchResultNode_(searchResultList[i]);
    }

    // Add/hide/show notification for removed results.
    var notificationDiv = document.querySelector(
        'div#' + blocklist.serp.NOTIFICATION_DIV_ID);
    var blockedResults = document.querySelectorAll(
        'div.' + blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);

    if (blockedResults.length > 0) {
      if (!notificationDiv) {
        blocklist.serp.addBlockListNotification_();
      } else {
        notificationDiv.setAttribute('style',
                                     blocklist.serp.NOTIFICATION_STYLE);
      }
    } else if (notificationDiv != null) {
      notificationDiv.setAttribute('style', 'display:none;');
    }

    blocklist.serp.needsRefresh = false;
  }
};

/**
 * Starts an infinite loop that applies the blocklist features to the page.
 * @private
 */
blocklist.serp.applyBlocklistFeatures_ = function() {
  window.setInterval(function() {
    blocklist.serp.modifySearchResults_();
  }, blocklist.serp.REPEAT_INTERVAL_IN_MS);
};

/**
 * Callback that handles the response of the local storage request.
 * @param {Array} response Response from the background page listener.
 */
blocklist.serp.handleAddToBlocklistResponse = function(response) {
  if (response.success) {
    blocklist.serp.refreshBlocklist();
    blocklist.serp.needsRefresh = true;
  }
};

/**
 * Callback that handles the response of the local storage request.
 * @param {Array} response Response from the background page listener.
 */
blocklist.serp.handleDeleteFromBlocklistResponse = function(response) {
  if (response.success) {
    // Reset blocked results and refresh.
    var searchResultList = document.querySelectorAll(
        'div.' + blocklist.serp.SEARCH_RESULT_CLASS);
    for (var i = 0; i < searchResultList.length; i++) {
      var pattern = blocklist.serp.parseDomainFromSearchResult_(
          searchResultList[i]);
      var subdomains = blocklist.serp.extractSubDomains_(pattern);
      if (blocklist.common.hasClass(
              searchResultList[i].className,
              blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS) &&
          subdomains.indexOf(response.pattern) != -1) {
        searchResultList[i].className = blocklist.common.removeClass(
            searchResultList[i].className,
            blocklist.serp.BLOCKED_VISIBLE_SEARCH_RESULT_CLASS);
        searchResultList[i].className = blocklist.common.removeClass(
            searchResultList[i].className,
            blocklist.serp.BLOCKED_SEARCH_RESULT_CLASS);
        // Clear the search result's background.
        searchResultList[i].setAttribute('style', 'background-color:inherit;');
      }
    }
    blocklist.serp.refreshBlocklist();
    blocklist.serp.needsRefresh = true;
  }
};

/**
 * Callback that handles the response of the local storage request.
 * @param {Array} response Response from the background page listener.
 */
blocklist.serp.handleGetBlocklistResponse = function(response) {
  if (response.blocklist != undefined) {
    blocklist.serp.blocklist = response.blocklist;
  }
};

/**
 * Retrieves blocklisted domains from localstorage.
 */
blocklist.serp.refreshBlocklist = function() {
  chrome.extension.sendRequest({type: blocklist.common.GETBLOCKLIST},
                               blocklist.serp.handleGetBlocklistResponse);
};

/**
 * Get if the current page is using https protocol.
 * @private
 */
blocklist.serp.getIsHttpsPage_ = function() {
  blocklist.serp.isHttps =
      (document.URL.indexOf('https://') == 0);
};

/**
 * Check if personalized web search is disabled (pws parameter is 0).
 * @return {boolean} True if url indicates personalized web search was disabled.
 * @private
 */
blocklist.serp.IsPwsDisabled_ = function() {
  return document.URL.match(blocklist.serp.PWS_REGEX) !== null;
};

/**
 * Get event id of this search result page.
 * @private
 */
blocklist.serp.getEventId_ = function() {
  blocklist.serp.eventId = 'null';
  try {
    var head = document.getElementsByTagName('head')[0];
    var scripts = head.getElementsByTagName('script');
    for (var i = 0; i < scripts.length; i++) {
      var script = scripts[i];
      var match = script.text.match(blocklist.serp.EVENT_ID_REGEX);
      if (match) {
        blocklist.serp.eventId = match[1];
      }
    }
  } catch (e) {
  }
};

/**
 * Exposes a listener, so that it can accept refresh request from manager.
 */
blocklist.serp.startBackgroundListeners = function() {
  chrome.extension.onRequest
        .addListener(function(request, sender, sendResponse) {
    if (request.type == blocklist.serp.REFRESH_REQUEST) {
      blocklist.serp.refreshBlocklist();
      blocklist.serp.needsRefresh = true;
    } else if (request.type == blocklist.serp.EXPORTTOGOOGLE_REQUEST) {
      document.write(request.html);
      chrome.extension.sendRequest({type: blocklist.common.FINISHEXPORT});
    }
  });
};

blocklist.serp.getIsHttpsPage_();
blocklist.serp.getEventId_();
blocklist.serp.refreshBlocklist();
blocklist.serp.applyBlocklistFeatures_();
blocklist.serp.startBackgroundListeners();