Merge commit '50d3e596bbe89c95615f96eb71f6bc5be737a1db' into Basilisk-releasev2018.07.18

# Conflicts:
#	browser/app/profile/firefox.js
#	browser/components/preferences/jar.mn

1 files changed, 1255 insertions, 0 deletions

diff --git a/application/basilisk/modules/DirectoryLinksProvider.jsm b/application/basilisk/modules/DirectoryLinksProvider.jsm
new file mode 100644
index 000000000..117564099
--- /dev/null
+++ b/application/basilisk/modules/DirectoryLinksProvider.jsm
@@ -0,0 +1,1255 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["DirectoryLinksProvider"];
+
+const Ci = Components.interfaces;
+const Cc = Components.classes;
+const Cu = Components.utils;
+const ParserUtils =  Cc["@mozilla.org/parserutils;1"].getService(Ci.nsIParserUtils);
+
+Cu.importGlobalProperties(["XMLHttpRequest"]);
+
+Cu.import("resource://gre/modules/XPCOMUtils.jsm");
+Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
+Cu.import("resource://gre/modules/Timer.jsm");
+
+XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
+  "resource://gre/modules/NetUtil.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "NewTabUtils",
+  "resource://gre/modules/NewTabUtils.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "OS",
+  "resource://gre/modules/osfile.jsm")
+XPCOMUtils.defineLazyModuleGetter(this, "Promise",
+  "resource://gre/modules/Promise.jsm");
+XPCOMUtils.defineLazyModuleGetter(this, "UpdateUtils",
+  "resource://gre/modules/UpdateUtils.jsm");
+XPCOMUtils.defineLazyServiceGetter(this, "eTLD",
+  "@mozilla.org/network/effective-tld-service;1",
+  "nsIEffectiveTLDService");
+XPCOMUtils.defineLazyGetter(this, "gTextDecoder", () => {
+  return new TextDecoder();
+});
+XPCOMUtils.defineLazyGetter(this, "gCryptoHash", function () {
+  return Cc["@mozilla.org/security/hash;1"].createInstance(Ci.nsICryptoHash);
+});
+XPCOMUtils.defineLazyGetter(this, "gUnicodeConverter", function () {
+  let converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
+                    .createInstance(Ci.nsIScriptableUnicodeConverter);
+  converter.charset = 'utf8';
+  return converter;
+});
+
+
+// The filename where directory links are stored locally
+const DIRECTORY_LINKS_FILE = "directoryLinks.json";
+const DIRECTORY_LINKS_TYPE = "application/json";
+
+// The preference that tells whether to match the OS locale
+const PREF_MATCH_OS_LOCALE = "intl.locale.matchOS";
+
+// The preference that tells what locale the user selected
+const PREF_SELECTED_LOCALE = "general.useragent.locale";
+
+// The preference that tells where to obtain directory links
+const PREF_DIRECTORY_SOURCE = "browser.newtabpage.directory.source";
+
+// The preference that tells where to send click/view pings
+const PREF_DIRECTORY_PING = "browser.newtabpage.directory.ping";
+
+// The preference that tells if newtab is enhanced
+const PREF_NEWTAB_ENHANCED = "browser.newtabpage.enhanced";
+
+// Only allow link urls that are http(s)
+const ALLOWED_LINK_SCHEMES = new Set(["http", "https"]);
+
+// Only allow link image urls that are https or data
+const ALLOWED_IMAGE_SCHEMES = new Set(["https", "data"]);
+
+// Only allow urls to Mozilla's CDN or empty (for data URIs)
+const ALLOWED_URL_BASE = new Set(["mozilla.net", ""]);
+
+// The frecency of a directory link
+const DIRECTORY_FRECENCY = 1000;
+
+// The frecency of a suggested link
+const SUGGESTED_FRECENCY = Infinity;
+
+// The filename where frequency cap data stored locally
+const FREQUENCY_CAP_FILE = "frequencyCap.json";
+
+// Default settings for daily and total frequency caps
+const DEFAULT_DAILY_FREQUENCY_CAP = 3;
+const DEFAULT_TOTAL_FREQUENCY_CAP = 10;
+
+// Default timeDelta to prune unused frequency cap objects
+// currently set to 10 days in milliseconds
+const DEFAULT_PRUNE_TIME_DELTA = 10*24*60*60*1000;
+
+// The min number of visible (not blocked) history tiles to have before showing suggested tiles
+const MIN_VISIBLE_HISTORY_TILES = 8;
+
+// The max number of visible (not blocked) history tiles to test for inadjacency
+const MAX_VISIBLE_HISTORY_TILES = 15;
+
+// Allowed ping actions remotely stored as columns: case-insensitive [a-z0-9_]
+const PING_ACTIONS = ["block", "click", "pin", "sponsored", "sponsored_link", "unpin", "view"];
+
+// Location of inadjacent sites json
+const INADJACENCY_SOURCE = "chrome://browser/content/newtab/newTab.inadjacent.json";
+
+// Fake URL to keep track of last block of a suggested tile in the frequency cap object
+const FAKE_SUGGESTED_BLOCK_URL = "ignore://suggested_block";
+
+// Time before suggested tile is allowed to play again after block - default to 1 day
+const AFTER_SUGGESTED_BLOCK_DECAY_TIME = 24*60*60*1000;
+
+/**
+ * Singleton that serves as the provider of directory links.
+ * Directory links are a hard-coded set of links shown if a user's link
+ * inventory is empty.
+ */
+var DirectoryLinksProvider = {
+
+  __linksURL: null,
+
+  _observers: new Set(),
+
+  // links download deferred, resolved upon download completion
+  _downloadDeferred: null,
+
+  // download default interval is 24 hours in milliseconds
+  _downloadIntervalMS: 86400000,
+
+  /**
+   * A mapping from eTLD+1 to an enhanced link objects
+   */
+  _enhancedLinks: new Map(),
+
+  /**
+   * A mapping from site to a list of suggested link objects
+   */
+  _suggestedLinks: new Map(),
+
+  /**
+   * Frequency Cap object - maintains daily and total tile counts, and frequency cap settings
+   */
+  _frequencyCaps: {},
+
+  /**
+   * A set of top sites that we can provide suggested links for
+   */
+  _topSitesWithSuggestedLinks: new Set(),
+
+  /**
+   * lookup Set of inadjacent domains
+   */
+  _inadjacentSites: new Set(),
+
+  /**
+   * This flag is set if there is a suggested tile configured to avoid
+   * inadjacent sites in new tab
+   */
+  _avoidInadjacentSites: false,
+
+  /**
+   * This flag is set if _avoidInadjacentSites is true and there is
+   * an inadjacent site in the new tab
+   */
+  _newTabHasInadjacentSite: false,
+
+  get _observedPrefs() {
+    return Object.freeze({
+      enhanced: PREF_NEWTAB_ENHANCED,
+      linksURL: PREF_DIRECTORY_SOURCE,
+      matchOSLocale: PREF_MATCH_OS_LOCALE,
+      prefSelectedLocale: PREF_SELECTED_LOCALE,
+    });
+  },
+
+  get _linksURL() {
+    if (!this.__linksURL) {
+      try {
+        this.__linksURL = Services.prefs.getCharPref(this._observedPrefs["linksURL"]);
+        this.__linksURLModified = Services.prefs.prefHasUserValue(this._observedPrefs["linksURL"]);
+      }
+      catch (e) {
+        Cu.reportError("Error fetching directory links url from prefs: " + e);
+      }
+    }
+    return this.__linksURL;
+  },
+
+  /**
+   * Gets the currently selected locale for display.
+   * @return  the selected locale or "en-US" if none is selected
+   */
+  get locale() {
+    let matchOS;
+    try {
+      matchOS = Services.prefs.getBoolPref(PREF_MATCH_OS_LOCALE);
+    }
+    catch (e) {}
+
+    if (matchOS) {
+      return Services.locale.getLocaleComponentForUserAgent();
+    }
+
+    try {
+      let locale = Services.prefs.getComplexValue(PREF_SELECTED_LOCALE,
+                                                  Ci.nsIPrefLocalizedString);
+      if (locale) {
+        return locale.data;
+      }
+    }
+    catch (e) {}
+
+    try {
+      return Services.prefs.getCharPref(PREF_SELECTED_LOCALE);
+    }
+    catch (e) {}
+
+    return "en-US";
+  },
+
+  /**
+   * Set appropriate default ping behavior controlled by enhanced pref
+   */
+  _setDefaultEnhanced: function DirectoryLinksProvider_setDefaultEnhanced() {
+    if (!Services.prefs.prefHasUserValue(PREF_NEWTAB_ENHANCED)) {
+      let enhanced = Services.prefs.getBoolPref(PREF_NEWTAB_ENHANCED);
+      try {
+        // Default to not enhanced if DNT is set to tell websites to not track
+        if (Services.prefs.getBoolPref("privacy.donottrackheader.enabled")) {
+          enhanced = false;
+        }
+      }
+      catch (ex) {}
+      Services.prefs.setBoolPref(PREF_NEWTAB_ENHANCED, enhanced);
+    }
+  },
+
+  observe: function DirectoryLinksProvider_observe(aSubject, aTopic, aData) {
+    if (aTopic == "nsPref:changed") {
+      switch (aData) {
+        // Re-set the default in case the user clears the pref
+        case this._observedPrefs.enhanced:
+          this._setDefaultEnhanced();
+          break;
+
+        case this._observedPrefs.linksURL:
+          delete this.__linksURL;
+          // fallthrough
+
+        // Force directory download on changes to fetch related prefs
+        case this._observedPrefs.matchOSLocale:
+        case this._observedPrefs.prefSelectedLocale:
+          this._fetchAndCacheLinksIfNecessary(true);
+          break;
+      }
+    }
+  },
+
+  _addPrefsObserver: function DirectoryLinksProvider_addObserver() {
+    for (let pref in this._observedPrefs) {
+      let prefName = this._observedPrefs[pref];
+      Services.prefs.addObserver(prefName, this, false);
+    }
+  },
+
+  _removePrefsObserver: function DirectoryLinksProvider_removeObserver() {
+    for (let pref in this._observedPrefs) {
+      let prefName = this._observedPrefs[pref];
+      Services.prefs.removeObserver(prefName, this);
+    }
+  },
+
+  _cacheSuggestedLinks: function(link) {
+    // Don't cache links that don't have the expected 'frecent_sites'
+    if (!link.frecent_sites) {
+      return;
+    }
+
+    for (let suggestedSite of link.frecent_sites) {
+      let suggestedMap = this._suggestedLinks.get(suggestedSite) || new Map();
+      suggestedMap.set(link.url, link);
+      this._setupStartEndTime(link);
+      this._suggestedLinks.set(suggestedSite, suggestedMap);
+    }
+  },
+
+  _fetchAndCacheLinks: function DirectoryLinksProvider_fetchAndCacheLinks(uri) {
+    // Replace with the same display locale used for selecting links data
+    uri = uri.replace("%LOCALE%", this.locale);
+    uri = uri.replace("%CHANNEL%", UpdateUtils.UpdateChannel);
+
+    return this._downloadJsonData(uri).then(json => {
+      return OS.File.writeAtomic(this._directoryFilePath, json, {tmpPath: this._directoryFilePath + ".tmp"});
+    });
+  },
+
+  /**
+   * Downloads a links with json content
+   * @param download uri
+   * @return promise resolved to json string, "{}" returned if status != 200
+   */
+  _downloadJsonData: function DirectoryLinksProvider__downloadJsonData(uri) {
+    let deferred = Promise.defer();
+    let xmlHttp = this._newXHR();
+
+    xmlHttp.onload = function(aResponse) {
+      let json = this.responseText;
+      if (this.status && this.status != 200) {
+        json = "{}";
+      }
+      deferred.resolve(json);
+    };
+
+    xmlHttp.onerror = function(e) {
+      deferred.reject("Fetching " + uri + " results in error code: " + e.target.status);
+    };
+
+    try {
+      xmlHttp.open("GET", uri);
+      // Override the type so XHR doesn't complain about not well-formed XML
+      xmlHttp.overrideMimeType(DIRECTORY_LINKS_TYPE);
+      // Set the appropriate request type for servers that require correct types
+      xmlHttp.setRequestHeader("Content-Type", DIRECTORY_LINKS_TYPE);
+      xmlHttp.send();
+    } catch (e) {
+      deferred.reject("Error fetching " + uri);
+      Cu.reportError(e);
+    }
+    return deferred.promise;
+  },
+
+  /**
+   * Downloads directory links if needed
+   * @return promise resolved immediately if no download needed, or upon completion
+   */
+  _fetchAndCacheLinksIfNecessary: function DirectoryLinksProvider_fetchAndCacheLinksIfNecessary(forceDownload=false) {
+    if (this._downloadDeferred) {
+      // fetching links already - just return the promise
+      return this._downloadDeferred.promise;
+    }
+
+    if (forceDownload || this._needsDownload) {
+      this._downloadDeferred = Promise.defer();
+      this._fetchAndCacheLinks(this._linksURL).then(() => {
+        // the new file was successfully downloaded and cached, so update a timestamp
+        this._lastDownloadMS = Date.now();
+        this._downloadDeferred.resolve();
+        this._downloadDeferred = null;
+        this._callObservers("onManyLinksChanged")
+      },
+      error => {
+        this._downloadDeferred.resolve();
+        this._downloadDeferred = null;
+        this._callObservers("onDownloadFail");
+      });
+      return this._downloadDeferred.promise;
+    }
+
+    // download is not needed
+    return Promise.resolve();
+  },
+
+  /**
+   * @return true if download is needed, false otherwise
+   */
+  get _needsDownload () {
+    // fail if last download occured less then 24 hours ago
+    if ((Date.now() - this._lastDownloadMS) > this._downloadIntervalMS) {
+      return true;
+    }
+    return false;
+  },
+
+  /**
+   * Create a new XMLHttpRequest that is anonymous, i.e., doesn't send cookies
+   */
+  _newXHR() {
+    return new XMLHttpRequest({mozAnon: true});
+  },
+
+  /**
+   * Reads directory links file and parses its content
+   * @return a promise resolved to an object with keys 'directory' and 'suggested',
+   *         each containing a valid list of links,
+   *         or {'directory': [], 'suggested': []} if read or parse fails.
+   */
+  _readDirectoryLinksFile: function DirectoryLinksProvider_readDirectoryLinksFile() {
+    let emptyOutput = {directory: [], suggested: [], enhanced: []};
+    return OS.File.read(this._directoryFilePath).then(binaryData => {
+      let output;
+      try {
+        let json = gTextDecoder.decode(binaryData);
+        let linksObj = JSON.parse(json);
+        output = {directory: linksObj.directory || [],
+                  suggested: linksObj.suggested || [],
+                  enhanced:  linksObj.enhanced  || []};
+      }
+      catch (e) {
+        Cu.reportError(e);
+      }
+      return output || emptyOutput;
+    },
+    error => {
+      Cu.reportError(error);
+      return emptyOutput;
+    });
+  },
+
+  /**
+   * Translates link.time_limits to UTC miliseconds and sets
+   * link.startTime and link.endTime properties in link object
+   */
+  _setupStartEndTime: function DirectoryLinksProvider_setupStartEndTime(link) {
+    // set start/end limits. Use ISO_8601 format: '2014-01-10T20:20:20.600Z'
+    // (details here http://en.wikipedia.org/wiki/ISO_8601)
+    // Note that if timezone is missing, FX will interpret as local time
+    // meaning that the server can sepecify any time, but if the capmaign
+    // needs to start at same time across multiple timezones, the server
+    // omits timezone indicator
+    if (!link.time_limits) {
+      return;
+    }
+
+    let parsedTime;
+    if (link.time_limits.start) {
+      parsedTime = Date.parse(link.time_limits.start);
+      if (parsedTime && !isNaN(parsedTime)) {
+        link.startTime = parsedTime;
+      }
+    }
+    if (link.time_limits.end) {
+      parsedTime = Date.parse(link.time_limits.end);
+      if (parsedTime && !isNaN(parsedTime)) {
+        link.endTime = parsedTime;
+      }
+    }
+  },
+
+  /*
+   * Handles campaign timeout
+   */
+  _onCampaignTimeout: function DirectoryLinksProvider_onCampaignTimeout() {
+    // _campaignTimeoutID is invalid here, so just set it to null
+    this._campaignTimeoutID = null;
+    this._updateSuggestedTile();
+  },
+
+  /*
+   * Clears capmpaign timeout
+   */
+  _clearCampaignTimeout: function DirectoryLinksProvider_clearCampaignTimeout() {
+    if (this._campaignTimeoutID) {
+      clearTimeout(this._campaignTimeoutID);
+      this._campaignTimeoutID = null;
+    }
+  },
+
+  /**
+   * Setup capmpaign timeout to recompute suggested tiles upon
+   * reaching soonest start or end time for the campaign
+   * @param timeout in milliseconds
+   */
+  _setupCampaignTimeCheck: function DirectoryLinksProvider_setupCampaignTimeCheck(timeout) {
+    // sanity check
+    if (!timeout || timeout <= 0) {
+      return;
+    }
+    this._clearCampaignTimeout();
+    // setup next timeout
+    this._campaignTimeoutID = setTimeout(this._onCampaignTimeout.bind(this), timeout);
+  },
+
+  /**
+   * Test link for campaign time limits: checks if link falls within start/end time
+   * and returns an object containing a use flag and the timeoutDate milliseconds
+   * when the link has to be re-checked for campaign start-ready or end-reach
+   * @param link
+   * @return object {use: true or false, timeoutDate: milliseconds or null}
+   */
+  _testLinkForCampaignTimeLimits: function DirectoryLinksProvider_testLinkForCampaignTimeLimits(link) {
+    let currentTime = Date.now();
+    // test for start time first
+    if (link.startTime && link.startTime > currentTime) {
+      // not yet ready for start
+      return {use: false, timeoutDate: link.startTime};
+    }
+    // otherwise check for end time
+    if (link.endTime) {
+      // passed end time
+      if (link.endTime <= currentTime) {
+        return {use: false};
+      }
+      // otherwise link is still ok, but we need to set timeoutDate
+      return {use: true, timeoutDate: link.endTime};
+    }
+    // if we are here, the link is ok and no timeoutDate needed
+    return {use: true};
+  },
+
+  /**
+   * Handles block on suggested tile: updates fake block url with current timestamp
+   */
+  handleSuggestedTileBlock: function DirectoryLinksProvider_handleSuggestedTileBlock() {
+    this._updateFrequencyCapSettings({url: FAKE_SUGGESTED_BLOCK_URL});
+    this._writeFrequencyCapFile();
+    this._updateSuggestedTile();
+  },
+
+  /**
+   * Checks if suggested tile is being blocked for the rest of "decay time"
+   * @return True if blocked, false otherwise
+   */
+  _isSuggestedTileBlocked: function DirectoryLinksProvider__isSuggestedTileBlocked() {
+    let capObject = this._frequencyCaps[FAKE_SUGGESTED_BLOCK_URL];
+    if (!capObject || !capObject.lastUpdated) {
+      // user never blocked suggested tile or lastUpdated is missing
+      return false;
+    }
+    // otherwise, make sure that enough time passed after suggested tile was blocked
+    return (capObject.lastUpdated + AFTER_SUGGESTED_BLOCK_DECAY_TIME) > Date.now();
+  },
+
+  /**
+   * Report some action on a newtab page (view, click)
+   * @param sites Array of sites shown on newtab page
+   * @param action String of the behavior to report
+   * @param triggeringSiteIndex optional Int index of the site triggering action
+   * @return download promise
+   */
+  reportSitesAction: function DirectoryLinksProvider_reportSitesAction(sites, action, triggeringSiteIndex) {
+    // Check if the suggested tile was shown
+    if (action == "view") {
+      sites.slice(0, triggeringSiteIndex + 1).filter(s => s).forEach(site => {
+        let {targetedSite, url} = site.link;
+        if (targetedSite) {
+          this._addFrequencyCapView(url);
+        }
+      });
+    }
+    // any click action on a suggested tile should stop that tile suggestion
+    // click/block - user either removed a tile or went to a landing page
+    // pin - tile turned into history tile, should no longer be suggested
+    // unpin - the tile was pinned before, should not matter
+    else {
+      // suggested tile has targetedSite, or frecent_sites if it was pinned
+      let {frecent_sites, targetedSite, url} = sites[triggeringSiteIndex].link;
+      if (frecent_sites || targetedSite) {
+        this._setFrequencyCapClick(url);
+      }
+    }
+
+    let newtabEnhanced = false;
+    let pingEndPoint = "";
+    try {
+      newtabEnhanced = Services.prefs.getBoolPref(PREF_NEWTAB_ENHANCED);
+      pingEndPoint = Services.prefs.getCharPref(PREF_DIRECTORY_PING);
+    }
+    catch (ex) {}
+
+    // Bug 1240245 - We no longer send pings, but frequency capping and fetching
+    // tests depend on the following actions, so references to PING remain.
+    let invalidAction = PING_ACTIONS.indexOf(action) == -1;
+    if (!newtabEnhanced || pingEndPoint == "" || invalidAction) {
+      return Promise.resolve();
+    }
+
+    return Task.spawn(function* () {
+      // since we updated views/clicks we need write _frequencyCaps to disk
+      yield this._writeFrequencyCapFile();
+      // Use this as an opportunity to potentially fetch new links
+      yield this._fetchAndCacheLinksIfNecessary();
+    }.bind(this));
+  },
+
+  /**
+   * Get the enhanced link object for a link (whether history or directory)
+   */
+  getEnhancedLink: function DirectoryLinksProvider_getEnhancedLink(link) {
+    // Use the provided link if it's already enhanced
+    return link.enhancedImageURI && link ? link :
+           this._enhancedLinks.get(NewTabUtils.extractSite(link.url));
+  },
+
+  /**
+   * Check if a url's scheme is in a Set of allowed schemes and if the base
+   * domain is allowed.
+   * @param url to check
+   * @param allowed Set of allowed schemes
+   * @param checkBase boolean to check the base domain
+   */
+  isURLAllowed(url, allowed, checkBase) {
+    // Assume no url is an allowed url
+    if (!url) {
+      return true;
+    }
+
+    let scheme = "", base = "";
+    try {
+      // A malformed url will not be allowed
+      let uri = Services.io.newURI(url, null, null);
+      scheme = uri.scheme;
+
+      // URIs without base domains will be allowed
+      base = Services.eTLD.getBaseDomain(uri);
+    }
+    catch (ex) {}
+    // Require a scheme match and the base only if desired
+    return allowed.has(scheme) && (!checkBase || ALLOWED_URL_BASE.has(base));
+  },
+
+  _escapeChars(text) {
+    let charMap = {
+      '&': '&amp;',
+      '<': '&lt;',
+      '>': '&gt;',
+      '"': '&quot;',
+      "'": '&#039;'
+    };
+
+    return text.replace(/[&<>"']/g, (character) => charMap[character]);
+  },
+
+  /**
+   * Gets the current set of directory links.
+   * @param aCallback The function that the array of links is passed to.
+   */
+  getLinks: function DirectoryLinksProvider_getLinks(aCallback) {
+    this._readDirectoryLinksFile().then(rawLinks => {
+      // Reset the cache of suggested tiles and enhanced images for this new set of links
+      this._enhancedLinks.clear();
+      this._suggestedLinks.clear();
+      this._clearCampaignTimeout();
+      this._avoidInadjacentSites = false;
+
+      // Only check base domain for images when using the default pref
+      let checkBase = !this.__linksURLModified;
+      let validityFilter = function(link) {
+        // Make sure the link url is allowed and images too if they exist
+        return this.isURLAllowed(link.url, ALLOWED_LINK_SCHEMES, false) &&
+               (!link.imageURI ||
+                this.isURLAllowed(link.imageURI, ALLOWED_IMAGE_SCHEMES, checkBase)) &&
+               (!link.enhancedImageURI ||
+                this.isURLAllowed(link.enhancedImageURI, ALLOWED_IMAGE_SCHEMES, checkBase));
+      }.bind(this);
+
+      rawLinks.suggested.filter(validityFilter).forEach((link, position) => {
+        // Suggested sites must have an adgroup name.
+        if (!link.adgroup_name) {
+          return;
+        }
+
+        let sanitizeFlags = ParserUtils.SanitizerCidEmbedsOnly |
+          ParserUtils.SanitizerDropForms |
+          ParserUtils.SanitizerDropNonCSSPresentation;
+
+        link.explanation = this._escapeChars(link.explanation ? ParserUtils.convertToPlainText(link.explanation, sanitizeFlags, 0) : "");
+        link.targetedName = this._escapeChars(ParserUtils.convertToPlainText(link.adgroup_name, sanitizeFlags, 0));
+        link.lastVisitDate = rawLinks.suggested.length - position;
+        // check if link wants to avoid inadjacent sites
+        if (link.check_inadjacency) {
+          this._avoidInadjacentSites = true;
+        }
+
+        // We cache suggested tiles here but do not push any of them in the links list yet.
+        // The decision for which suggested tile to include will be made separately.
+        this._cacheSuggestedLinks(link);
+        this._updateFrequencyCapSettings(link);
+      });
+
+      rawLinks.enhanced.filter(validityFilter).forEach((link, position) => {
+        link.lastVisitDate = rawLinks.enhanced.length - position;
+
+        // Stash the enhanced image for the site
+        if (link.enhancedImageURI) {
+          this._enhancedLinks.set(NewTabUtils.extractSite(link.url), link);
+        }
+      });
+
+      let links = rawLinks.directory.filter(validityFilter).map((link, position) => {
+        link.lastVisitDate = rawLinks.directory.length - position;
+        link.frecency = DIRECTORY_FRECENCY;
+        return link;
+      });
+
+      // Allow for one link suggestion on top of the default directory links
+      this.maxNumLinks = links.length + 1;
+
+      // prune frequency caps of outdated urls
+      this._pruneFrequencyCapUrls();
+      // write frequency caps object to disk asynchronously
+      this._writeFrequencyCapFile();
+
+      return links;
+    }).catch(ex => {
+      Cu.reportError(ex);
+      return [];
+    }).then(links => {
+      aCallback(links);
+      this._populatePlacesLinks();
+    });
+  },
+
+  init: function DirectoryLinksProvider_init() {
+    this._setDefaultEnhanced();
+    this._addPrefsObserver();
+    // setup directory file path and last download timestamp
+    this._directoryFilePath = OS.Path.join(OS.Constants.Path.localProfileDir, DIRECTORY_LINKS_FILE);
+    this._lastDownloadMS = 0;
+
+    // setup frequency cap file path
+    this._frequencyCapFilePath = OS.Path.join(OS.Constants.Path.localProfileDir, FREQUENCY_CAP_FILE);
+    // setup inadjacent sites URL
+    this._inadjacentSitesUrl = INADJACENCY_SOURCE;
+
+    NewTabUtils.placesProvider.addObserver(this);
+    NewTabUtils.links.addObserver(this);
+
+    return Task.spawn(function*() {
+      // get the last modified time of the links file if it exists
+      let doesFileExists = yield OS.File.exists(this._directoryFilePath);
+      if (doesFileExists) {
+        let fileInfo = yield OS.File.stat(this._directoryFilePath);
+        this._lastDownloadMS = Date.parse(fileInfo.lastModificationDate);
+      }
+      // read frequency cap file
+      yield this._readFrequencyCapFile();
+      // fetch directory on startup without force
+      yield this._fetchAndCacheLinksIfNecessary();
+      // fecth inadjacent sites on startup
+      yield this._loadInadjacentSites();
+    }.bind(this));
+  },
+
+  _handleManyLinksChanged: function() {
+    this._topSitesWithSuggestedLinks.clear();
+    this._suggestedLinks.forEach((suggestedLinks, site) => {
+      if (NewTabUtils.isTopPlacesSite(site)) {
+        this._topSitesWithSuggestedLinks.add(site);
+      }
+    });
+    this._updateSuggestedTile();
+  },
+
+  /**
+   * Updates _topSitesWithSuggestedLinks based on the link that was changed.
+   *
+   * @return true if _topSitesWithSuggestedLinks was modified, false otherwise.
+   */
+  _handleLinkChanged: function(aLink) {
+    let changedLinkSite = NewTabUtils.extractSite(aLink.url);
+    let linkStored = this._topSitesWithSuggestedLinks.has(changedLinkSite);
+
+    if (!NewTabUtils.isTopPlacesSite(changedLinkSite) && linkStored) {
+      this._topSitesWithSuggestedLinks.delete(changedLinkSite);
+      return true;
+    }
+
+    if (this._suggestedLinks.has(changedLinkSite) &&
+        NewTabUtils.isTopPlacesSite(changedLinkSite) && !linkStored) {
+      this._topSitesWithSuggestedLinks.add(changedLinkSite);
+      return true;
+    }
+
+    // always run _updateSuggestedTile if aLink is inadjacent
+    // and there are tiles configured to avoid it
+    if (this._avoidInadjacentSites && this._isInadjacentLink(aLink)) {
+      return true;
+    }
+
+    return false;
+  },
+
+  _populatePlacesLinks: function () {
+    NewTabUtils.links.populateProviderCache(NewTabUtils.placesProvider, () => {
+      this._handleManyLinksChanged();
+    });
+  },
+
+  onDeleteURI: function(aProvider, aLink) {
+    let {url} = aLink;
+    // remove clicked flag for that url and
+    // call observer upon disk write completion
+    this._removeTileClick(url).then(() => {
+      this._callObservers("onDeleteURI", url);
+    });
+  },
+
+  onClearHistory: function() {
+    // remove all clicked flags and call observers upon file write
+    this._removeAllTileClicks().then(() => {
+      this._callObservers("onClearHistory");
+    });
+  },
+
+  onLinkChanged: function (aProvider, aLink) {
+    // Make sure NewTabUtils.links handles the notification first.
+    setTimeout(() => {
+      if (this._handleLinkChanged(aLink) || this._shouldUpdateSuggestedTile()) {
+        this._updateSuggestedTile();
+      }
+    }, 0);
+  },
+
+  onManyLinksChanged: function () {
+    // Make sure NewTabUtils.links handles the notification first.
+    setTimeout(() => {
+      this._handleManyLinksChanged();
+    }, 0);
+  },
+
+  _getCurrentTopSiteCount: function() {
+    let visibleTopSiteCount = 0;
+    let newTabLinks = NewTabUtils.links.getLinks();
+    for (let link of newTabLinks.slice(0, MIN_VISIBLE_HISTORY_TILES)) {
+      // compute visibleTopSiteCount for suggested tiles
+      if (link && (link.type == "history" || link.type == "enhanced")) {
+        visibleTopSiteCount++;
+      }
+    }
+    // since newTabLinks are available, set _newTabHasInadjacentSite here
+    // note that _shouldUpdateSuggestedTile is called by _updateSuggestedTile
+    this._newTabHasInadjacentSite = this._avoidInadjacentSites && this._checkForInadjacentSites(newTabLinks);
+
+    return visibleTopSiteCount;
+  },
+
+  _shouldUpdateSuggestedTile: function() {
+    let sortedLinks = NewTabUtils.getProviderLinks(this);
+
+    let mostFrecentLink = {};
+    if (sortedLinks && sortedLinks.length) {
+      mostFrecentLink = sortedLinks[0]
+    }
+
+    let currTopSiteCount = this._getCurrentTopSiteCount();
+    if ((!mostFrecentLink.targetedSite && currTopSiteCount >= MIN_VISIBLE_HISTORY_TILES) ||
+        (mostFrecentLink.targetedSite && currTopSiteCount < MIN_VISIBLE_HISTORY_TILES)) {
+      // If mostFrecentLink has a targetedSite then mostFrecentLink is a suggested link.
+      // If we have enough history links (8+) to show a suggested tile and we are not
+      // already showing one, then we should update (to *attempt* to add a suggested tile).
+      // OR if we don't have enough history to show a suggested tile (<8) and we are
+      // currently showing one, we should update (to remove it).
+      return true;
+    }
+
+    return false;
+  },
+
+  /**
+   * Chooses and returns a suggested tile based on a user's top sites
+   * that we have an available suggested tile for.
+   *
+   * @return the chosen suggested tile, or undefined if there isn't one
+   */
+  _updateSuggestedTile: function() {
+    let sortedLinks = NewTabUtils.getProviderLinks(this);
+
+    if (!sortedLinks) {
+      // If NewTabUtils.links.resetCache() is called before getting here,
+      // sortedLinks may be undefined.
+      return undefined;
+    }
+
+    // Delete the current suggested tile, if one exists.
+    let initialLength = sortedLinks.length;
+    if (initialLength) {
+      let mostFrecentLink = sortedLinks[0];
+      if (mostFrecentLink.targetedSite) {
+        this._callObservers("onLinkChanged", {
+          url: mostFrecentLink.url,
+          frecency: SUGGESTED_FRECENCY,
+          lastVisitDate: mostFrecentLink.lastVisitDate,
+          type: mostFrecentLink.type,
+        }, 0, true);
+      }
+    }
+
+    if (this._topSitesWithSuggestedLinks.size == 0 ||
+        !this._shouldUpdateSuggestedTile() ||
+        this._isSuggestedTileBlocked()) {
+      // There are no potential suggested links we can show or not
+      // enough history for a suggested tile, or suggested tile was
+      // recently blocked and wait time interval has not decayed yet
+      return undefined;
+    }
+
+    // Create a flat list of all possible links we can show as suggested.
+    // Note that many top sites may map to the same suggested links, but we only
+    // want to count each suggested link once (based on url), thus possibleLinks is a map
+    // from url to suggestedLink. Thus, each link has an equal chance of being chosen at
+    // random from flattenedLinks if it appears only once.
+    let nextTimeout;
+    let possibleLinks = new Map();
+    let targetedSites = new Map();
+    this._topSitesWithSuggestedLinks.forEach(topSiteWithSuggestedLink => {
+      let suggestedLinksMap = this._suggestedLinks.get(topSiteWithSuggestedLink);
+      suggestedLinksMap.forEach((suggestedLink, url) => {
+        // Skip this link if we've shown it too many times already
+        if (!this._testFrequencyCapLimits(url)) {
+          return;
+        }
+
+        // as we iterate suggestedLinks, check for campaign start/end
+        // time limits, and set nextTimeout to the closest timestamp
+        let {use, timeoutDate} = this._testLinkForCampaignTimeLimits(suggestedLink);
+        // update nextTimeout is necessary
+        if (timeoutDate && (!nextTimeout || nextTimeout > timeoutDate)) {
+          nextTimeout = timeoutDate;
+        }
+        // Skip link if it falls outside campaign time limits
+        if (!use) {
+          return;
+        }
+
+        // Skip link if it avoids inadjacent sites and newtab has one
+        if (suggestedLink.check_inadjacency && this._newTabHasInadjacentSite) {
+          return;
+        }
+
+        possibleLinks.set(url, suggestedLink);
+
+        // Keep a map of URL to targeted sites. We later use this to show the user
+        // what site they visited to trigger this suggestion.
+        if (!targetedSites.get(url)) {
+          targetedSites.set(url, []);
+        }
+        targetedSites.get(url).push(topSiteWithSuggestedLink);
+      })
+    });
+
+    // setup timeout check for starting or ending campaigns
+    if (nextTimeout) {
+      this._setupCampaignTimeCheck(nextTimeout - Date.now());
+    }
+
+    // We might have run out of possible links to show
+    let numLinks = possibleLinks.size;
+    if (numLinks == 0) {
+      return undefined;
+    }
+
+    let flattenedLinks = [...possibleLinks.values()];
+
+    // Choose our suggested link at random
+    let suggestedIndex = Math.floor(Math.random() * numLinks);
+    let chosenSuggestedLink = flattenedLinks[suggestedIndex];
+
+    // Add the suggested link to the front with some extra values
+    this._callObservers("onLinkChanged", Object.assign({
+      frecency: SUGGESTED_FRECENCY,
+
+      // Choose the first site a user has visited as the target. In the future,
+      // this should be the site with the highest frecency. However, we currently
+      // store frecency by URL not by site.
+      targetedSite: targetedSites.get(chosenSuggestedLink.url).length ?
+        targetedSites.get(chosenSuggestedLink.url)[0] : null
+    }, chosenSuggestedLink));
+    return chosenSuggestedLink;
+   },
+
+  /**
+   * Loads inadjacent sites
+   * @return a promise resolved when lookup Set for sites is built
+   */
+  _loadInadjacentSites: function DirectoryLinksProvider_loadInadjacentSites() {
+    return this._downloadJsonData(this._inadjacentSitesUrl).then(jsonString => {
+      let jsonObject = {};
+      try {
+        jsonObject = JSON.parse(jsonString);
+      }
+      catch (e) {
+        Cu.reportError(e);
+      }
+
+      this._inadjacentSites = new Set(jsonObject.domains);
+    });
+  },
+
+  /**
+   * Genegrates hash suitable for looking up inadjacent site
+   * @param value to hsh
+   * @return hased value, base64-ed
+   */
+  _generateHash: function DirectoryLinksProvider_generateHash(value) {
+    let byteArr = gUnicodeConverter.convertToByteArray(value);
+    gCryptoHash.init(gCryptoHash.MD5);
+    gCryptoHash.update(byteArr, byteArr.length);
+    return gCryptoHash.finish(true);
+  },
+
+  /**
+   * Checks if link belongs to inadjacent domain
+   * @param link to check
+   * @return true for inadjacent domains, false otherwise
+   */
+  _isInadjacentLink: function DirectoryLinksProvider_isInadjacentLink(link) {
+    let baseDomain = link.baseDomain || NewTabUtils.extractSite(link.url || "");
+    if (!baseDomain) {
+        return false;
+    }
+    // check if hashed domain is inadjacent
+    return this._inadjacentSites.has(this._generateHash(baseDomain));
+  },
+
+  /**
+   * Checks if new tab has inadjacent site
+   * @param new tab links (or nothing, in which case NewTabUtils.links.getLinks() is called
+   * @return true if new tab shows has inadjacent site
+   */
+  _checkForInadjacentSites: function DirectoryLinksProvider_checkForInadjacentSites(newTabLink) {
+    let links = newTabLink || NewTabUtils.links.getLinks();
+    for (let link of links.slice(0, MAX_VISIBLE_HISTORY_TILES)) {
+      // check links against inadjacent list - specifically include ALL link types
+      if (this._isInadjacentLink(link)) {
+        return true;
+      }
+    }
+    return false;
+  },
+
+  /**
+   * Reads json file, parses its content, and returns resulting object
+   * @param json file path
+   * @param json object to return in case file read or parse fails
+   * @return a promise resolved to a valid object or undefined upon error
+   */
+  _readJsonFile: Task.async(function* (filePath, nullObject) {
+    let jsonObj;
+    try {
+      let binaryData = yield OS.File.read(filePath);
+      let json = gTextDecoder.decode(binaryData);
+      jsonObj = JSON.parse(json);
+    }
+    catch (e) {}
+    return jsonObj || nullObject;
+  }),
+
+  /**
+   * Loads frequency cap object from file and parses its content
+   * @return a promise resolved upon load completion
+   *         on error or non-exstent file _frequencyCaps is set to empty object
+   */
+  _readFrequencyCapFile: Task.async(function* () {
+    // set _frequencyCaps object to file's content or empty object
+    this._frequencyCaps = yield this._readJsonFile(this._frequencyCapFilePath, {});
+  }),
+
+  /**
+   * Saves frequency cap object to file
+   * @return a promise resolved upon file i/o completion
+   */
+  _writeFrequencyCapFile: function DirectoryLinksProvider_writeFrequencyCapFile() {
+    let json = JSON.stringify(this._frequencyCaps || {});
+    return OS.File.writeAtomic(this._frequencyCapFilePath, json, {tmpPath: this._frequencyCapFilePath + ".tmp"});
+  },
+
+  /**
+   * Clears frequency cap object and writes empty json to file
+   * @return a promise resolved upon file i/o completion
+   */
+  _clearFrequencyCap: function DirectoryLinksProvider_clearFrequencyCap() {
+    this._frequencyCaps = {};
+    return this._writeFrequencyCapFile();
+  },
+
+  /**
+   * updates frequency cap configuration for a link
+   */
+  _updateFrequencyCapSettings: function DirectoryLinksProvider_updateFrequencyCapSettings(link) {
+    let capsObject = this._frequencyCaps[link.url];
+    if (!capsObject) {
+      // create an object with empty counts
+      capsObject = {
+        dailyViews: 0,
+        totalViews: 0,
+        lastShownDate: 0,
+      };
+      this._frequencyCaps[link.url] = capsObject;
+    }
+    // set last updated timestamp
+    capsObject.lastUpdated = Date.now();
+    // check for link configuration
+    if (link.frequency_caps) {
+      capsObject.dailyCap = link.frequency_caps.daily || DEFAULT_DAILY_FREQUENCY_CAP;
+      capsObject.totalCap = link.frequency_caps.total || DEFAULT_TOTAL_FREQUENCY_CAP;
+    }
+    else {
+      // fallback to defaults
+      capsObject.dailyCap = DEFAULT_DAILY_FREQUENCY_CAP;
+      capsObject.totalCap = DEFAULT_TOTAL_FREQUENCY_CAP;
+    }
+  },
+
+  /**
+   * Prunes frequency cap objects for outdated links
+   * @param timeDetla milliseconds
+   *        all cap objects with lastUpdated less than (now() - timeDelta)
+   *        will be removed. This is done to remove frequency cap objects
+   *        for unused tile urls
+   */
+  _pruneFrequencyCapUrls: function DirectoryLinksProvider_pruneFrequencyCapUrls(timeDelta = DEFAULT_PRUNE_TIME_DELTA) {
+    let timeThreshold = Date.now() - timeDelta;
+    Object.keys(this._frequencyCaps).forEach(url => {
+      // remove url if it is not ignorable and wasn't updated for a while
+      if (!url.startsWith("ignore") && this._frequencyCaps[url].lastUpdated <= timeThreshold) {
+        delete this._frequencyCaps[url];
+      }
+    });
+  },
+
+  /**
+   * Checks if supplied timestamp happened today
+   * @param timestamp in milliseconds
+   * @return true if the timestamp was made today, false otherwise
+   */
+  _wasToday: function DirectoryLinksProvider_wasToday(timestamp) {
+    let showOn = new Date(timestamp);
+    let today = new Date();
+    // call timestamps identical if both day and month are same
+    return showOn.getDate() == today.getDate() &&
+           showOn.getMonth() == today.getMonth() &&
+           showOn.getYear() == today.getYear();
+  },
+
+  /**
+   * adds some number of views for a url
+   * @param url String url of the suggested link
+   */
+  _addFrequencyCapView: function DirectoryLinksProvider_addFrequencyCapView(url) {
+    let capObject = this._frequencyCaps[url];
+    // sanity check
+    if (!capObject) {
+      return;
+    }
+
+    // if the day is new: reset the daily counter and lastShownDate
+    if (!this._wasToday(capObject.lastShownDate)) {
+      capObject.dailyViews = 0;
+      // update lastShownDate
+      capObject.lastShownDate = Date.now();
+    }
+
+    // bump both daily and total counters
+    capObject.totalViews++;
+    capObject.dailyViews++;
+
+    // if any of the caps is reached - update suggested tiles
+    if (capObject.totalViews >= capObject.totalCap ||
+        capObject.dailyViews >= capObject.dailyCap) {
+      this._updateSuggestedTile();
+    }
+  },
+
+  /**
+   * Sets clicked flag for link url
+   * @param url String url of the suggested link
+   */
+  _setFrequencyCapClick(url) {
+    let capObject = this._frequencyCaps[url];
+    // sanity check
+    if (!capObject) {
+      return;
+    }
+    capObject.clicked = true;
+    // and update suggested tiles, since current tile became invalid
+    this._updateSuggestedTile();
+  },
+
+  /**
+   * Tests frequency cap limits for link url
+   * @param url String url of the suggested link
+   * @return true if link is viewable, false otherwise
+   */
+  _testFrequencyCapLimits: function DirectoryLinksProvider_testFrequencyCapLimits(url) {
+    let capObject = this._frequencyCaps[url];
+    // sanity check: if url is missing - do not show this tile
+    if (!capObject) {
+      return false;
+    }
+
+    // check for clicked set or total views reached
+    if (capObject.clicked || capObject.totalViews >= capObject.totalCap) {
+      return false;
+    }
+
+    // otherwise check if link is over daily views limit
+    if (this._wasToday(capObject.lastShownDate) &&
+        capObject.dailyViews >= capObject.dailyCap) {
+      return false;
+    }
+
+    // we passed all cap tests: return true
+    return true;
+  },
+
+  /**
+   * Removes clicked flag from frequency cap entry for tile landing url
+   * @param url String url of the suggested link
+   * @return promise resolved upon disk write completion
+   */
+  _removeTileClick: function DirectoryLinksProvider_removeTileClick(url = "") {
+    // remove trailing slash, to accomodate Places sending site urls ending with '/'
+    let noTrailingSlashUrl = url.replace(/\/$/, "");
+    let capObject = this._frequencyCaps[url] || this._frequencyCaps[noTrailingSlashUrl];
+    // return resolved promise if capObject is not found
+    if (!capObject) {
+      return Promise.resolve();
+    }
+    // otherwise remove clicked flag
+    delete capObject.clicked;
+    return this._writeFrequencyCapFile();
+  },
+
+  /**
+   * Removes all clicked flags from frequency cap object
+   * @return promise resolved upon disk write completion
+   */
+  _removeAllTileClicks: function DirectoryLinksProvider_removeAllTileClicks() {
+    Object.keys(this._frequencyCaps).forEach(url => {
+      delete this._frequencyCaps[url].clicked;
+    });
+    return this._writeFrequencyCapFile();
+  },
+
+  /**
+   * Return the object to its pre-init state
+   */
+  reset: function DirectoryLinksProvider_reset() {
+    delete this.__linksURL;
+    this._removePrefsObserver();
+    this._removeObservers();
+  },
+
+  addObserver: function DirectoryLinksProvider_addObserver(aObserver) {
+    this._observers.add(aObserver);
+  },
+
+  removeObserver: function DirectoryLinksProvider_removeObserver(aObserver) {
+    this._observers.delete(aObserver);
+  },
+
+  _callObservers(methodName, ...args) {
+    for (let obs of this._observers) {
+      if (typeof(obs[methodName]) == "function") {
+        try {
+          obs[methodName](this, ...args);
+        } catch (err) {
+          Cu.reportError(err);
+        }
+      }
+    }
+  },
+
+  _removeObservers: function() {
+    this._observers.clear();
+  }
+};