toolkit/components/places/History.jsm
author i.milind.luthra+590334 <i.milind.luthra@gmail.com>
Thu, 11 May 2017 17:22:27 +0200
changeset 357847 8840f2afc5f942d73384ddcc7e4456a53408b619
parent 355517 70664c1a78fd00b10033069f007c21ac809f5f20
child 358070 7970ea0858614c4de33e32fb59738ddc9c3efc23
permissions -rw-r--r--
Bug 1249263 - add a `removeByFilter` method to filter by host and time,r=mak Added a method in History to filter by host and timeframe, which is designed to act as a replacement for `RemovePagesByTimeFrame` and `RemovePagesFromHost` in the old API. The `filter` object accepts both a host argument, as well as a timeframe, and filters as per one or both of them. This also moves certain code (the method `validatePageInfo` and methods it uses) from History to PlacesUtils such that we can use it for testing as well, and modifies the method to take another parameter which decides whether the visits inside the pageInfo need to be validated as well (since the pageInfo returned from History.jsm::`remove` and History.jsm::`removeByFilter` do not pass a visits array in their callback functions. Shifts `ensureDate` and `isValidTransitionType`(now renamed to `isValidTransition`) inside the history object. MozReview-Commit-ID: EQAHmjf7131

/* 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";

/**
 * Asynchronous API for managing history.
 *
 *
 * The API makes use of `PageInfo` and `VisitInfo` objects, defined as follows.
 *
 * A `PageInfo` object is any object that contains A SUBSET of the
 * following properties:
 * - guid: (string)
 *     The globally unique id of the page.
 * - url: (URL)
 *     or (nsIURI)
 *     or (string)
 *     The full URI of the page. Note that `PageInfo` values passed as
 *     argument may hold `nsIURI` or `string` values for property `url`,
 *     but `PageInfo` objects returned by this module always hold `URL`
 *     values.
 * - title: (string)
 *     The title associated with the page, if any.
 * - frecency: (number)
 *     The frecency of the page, if any.
 *     See https://developer.mozilla.org/en-US/docs/Mozilla/Tech/Places/Frecency_algorithm
 *     Note that this property may not be used to change the actualy frecency
 *     score of a page, only to retrieve it. In other words, any `frecency` field
 *     passed as argument to a function of this API will be ignored.
 *  - visits: (Array<VisitInfo>)
 *     All the visits for this page, if any.
 *
 * See the documentation of individual methods to find out which properties
 * are required for `PageInfo` arguments or returned for `PageInfo` results.
 *
 * A `VisitInfo` object is any object that contains A SUBSET of the following
 * properties:
 * - date: (Date)
 *     The time the visit occurred.
 * - transition: (number)
 *     How the user reached the page. See constants `TRANSITIONS.*`
 *     for the possible transition types.
 * - referrer: (URL)
 *          or (nsIURI)
 *          or (string)
 *     The referring URI of this visit. Note that `VisitInfo` passed
 *     as argument may hold `nsIURI` or `string` values for property `referrer`,
 *     but `VisitInfo` objects returned by this module always hold `URL`
 *     values.
 * See the documentation of individual methods to find out which properties
 * are required for `VisitInfo` arguments or returned for `VisitInfo` results.
 *
 *
 *
 * Each successful operation notifies through the nsINavHistoryObserver
 * interface. To listen to such notifications you must register using
 * nsINavHistoryService `addObserver` and `removeObserver` methods.
 * @see nsINavHistoryObserver
 */

this.EXPORTED_SYMBOLS = [ "History" ];

const { classes: Cc, interfaces: Ci, results: Cr, utils: Cu } = Components;

Cu.import("resource://gre/modules/XPCOMUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "AsyncShutdown",
                                  "resource://gre/modules/AsyncShutdown.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Services",
                                  "resource://gre/modules/Services.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "NetUtil",
                                  "resource://gre/modules/NetUtil.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Promise",
                                  "resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Task",
                                  "resource://gre/modules/Task.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Sqlite",
                                  "resource://gre/modules/Sqlite.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PlacesUtils",
                                  "resource://gre/modules/PlacesUtils.jsm");
Cu.importGlobalProperties(["URL"]);

/**
 * Whenever we update or remove numerous pages, it is preferable
 * to yield time to the main thread every so often to avoid janking.
 * These constants determine the maximal number of notifications we
 * may emit before we yield.
 */
const NOTIFICATION_CHUNK_SIZE = 300;
const ONRESULT_CHUNK_SIZE = 300;

// This constant determines the maximum number of remove pages before we cycle.
const REMOVE_PAGES_CHUNKLEN = 300;


/**
 * Sends a bookmarks notification through the given observers.
 *
 * @param observers
 *        array of nsINavBookmarkObserver objects.
 * @param notification
 *        the notification name.
 * @param args
 *        array of arguments to pass to the notification.
 */
function notify(observers, notification, args = []) {
  for (let observer of observers) {
    try {
      observer[notification](...args);
    } catch (ex) {}
  }
}

this.History = Object.freeze({
  /**
   * Fetch the available information for one page.
   *
   * @param guidOrURI: (URL or nsIURI)
   *      The full URI of the page.
   *            or (string)
   *      Either the full URI of the page or the GUID of the page.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolves (PageInfo | null) If the page could be found, the information
   *      on that page. Note that this `PageInfo` does NOT contain the visit
   *      data (i.e. `visits` is `undefined`).
   *
   * @throws (Error)
   *      If `guidOrURI` does not have the expected type or if it is a string
   *      that may be parsed neither as a valid URL nor as a valid GUID.
   */
  fetch(guidOrURI) {
    throw new Error("Method not implemented");
  },

  /**
   * Adds a number of visits for a single page.
   *
   * Any change may be observed through nsINavHistoryObserver
   *
   * @param pageInfo: (PageInfo)
   *      Information on a page. This `PageInfo` MUST contain
   *        - a property `url`, as specified by the definition of `PageInfo`.
   *        - a property `visits`, as specified by the definition of
   *          `PageInfo`, which MUST contain at least one visit.
   *      If a property `title` is provided, the title of the page
   *      is updated.
   *      If the `date` of a visit is not provided, it defaults
   *      to now.
   *      If the `transition` of a visit is not provided, it defaults to
   *      TRANSITION_LINK.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolves (PageInfo)
   *      A PageInfo object populated with data after the insert is complete.
   * @rejects (Error)
   *      Rejects if the insert was unsuccessful.
   *
   * @throws (Error)
   *      If the `url` specified was for a protocol that should not be
   *      stored (@see nsNavHistory::CanAddURI).
   * @throws (Error)
   *      If `pageInfo` has an unexpected type.
   * @throws (Error)
   *      If `pageInfo` does not have a `url`.
   * @throws (Error)
   *      If `pageInfo` does not have a `visits` property or if the
   *      value of `visits` is ill-typed or is an empty array.
   * @throws (Error)
   *      If an element of `visits` has an invalid `date`.
   * @throws (Error)
   *      If an element of `visits` has an invalid `transition`.
   */
  insert(pageInfo) {
    if (typeof pageInfo != "object" || !pageInfo) {
      throw new TypeError("pageInfo must be an object");
    }

    let info = PlacesUtils.validatePageInfo(pageInfo);

    return PlacesUtils.withConnectionWrapper("History.jsm: insert",
      db => insert(db, info));
  },

  /**
   * Adds a number of visits for a number of pages.
   *
   * Any change may be observed through nsINavHistoryObserver
   *
   * @param pageInfos: (Array<PageInfo>)
   *      Information on a page. This `PageInfo` MUST contain
   *        - a property `url`, as specified by the definition of `PageInfo`.
   *        - a property `visits`, as specified by the definition of
   *          `PageInfo`, which MUST contain at least one visit.
   *      If a property `title` is provided, the title of the page
   *      is updated.
   *      If the `date` of a visit is not provided, it defaults
   *      to now.
   *      If the `transition` of a visit is not provided, it defaults to
   *      TRANSITION_LINK.
   * @param onResult: (function(PageInfo))
   *      A callback invoked for each page inserted.
   * @param onError: (function(PageInfo))
   *      A callback invoked for each page which generated an error
   *      when an insert was attempted.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolves (null)
   * @rejects (Error)
   *      Rejects if all of the inserts were unsuccessful.
   *
   * @throws (Error)
   *      If the `url` specified was for a protocol that should not be
   *      stored (@see nsNavHistory::CanAddURI).
   * @throws (Error)
   *      If `pageInfos` has an unexpected type.
   * @throws (Error)
   *      If a `pageInfo` does not have a `url`.
   * @throws (Error)
   *      If a `PageInfo` does not have a `visits` property or if the
   *      value of `visits` is ill-typed or is an empty array.
   * @throws (Error)
   *      If an element of `visits` has an invalid `date`.
   * @throws (Error)
   *      If an element of `visits` has an invalid `transition`.
   */
  insertMany(pageInfos, onResult, onError) {
    let infos = [];

    if (!Array.isArray(pageInfos)) {
      throw new TypeError("pageInfos must be an array");
    }
    if (!pageInfos.length) {
      throw new TypeError("pageInfos may not be an empty array");
    }

    if (onResult && typeof onResult != "function") {
      throw new TypeError(`onResult: ${onResult} is not a valid function`);
    }
    if (onError && typeof onError != "function") {
      throw new TypeError(`onError: ${onError} is not a valid function`);
    }

    for (let pageInfo of pageInfos) {
      let info = PlacesUtils.validatePageInfo(pageInfo);
      infos.push(info);
    }

    return PlacesUtils.withConnectionWrapper("History.jsm: insertMany",
      db => insertMany(db, infos, onResult, onError));
  },

  /**
   * Remove pages from the database.
   *
   * Any change may be observed through nsINavHistoryObserver
   *
   *
   * @param page: (URL or nsIURI)
   *      The full URI of the page.
   *             or (string)
   *      Either the full URI of the page or the GUID of the page.
   *             or (Array<URL|nsIURI|string>)
   *      An array of the above, to batch requests.
   * @param onResult: (function(PageInfo))
   *      A callback invoked for each page found.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolve (bool)
   *      `true` if at least one page was removed, `false` otherwise.
   * @throws (TypeError)
   *       If `pages` has an unexpected type or if a string provided
   *       is neither a valid GUID nor a valid URI or if `pages`
   *       is an empty array.
   */
  remove(pages, onResult = null) {
    // Normalize and type-check arguments
    if (Array.isArray(pages)) {
      if (pages.length == 0) {
        throw new TypeError("Expected at least one page");
      }
    } else {
      pages = [pages];
    }

    let guids = [];
    let urls = [];
    for (let page of pages) {
      // Normalize to URL or GUID, or throw if `page` cannot
      // be normalized.
      let normalized = PlacesUtils.normalizeToURLOrGUID(page);
      if (typeof normalized === "string") {
        guids.push(normalized);
      } else {
        urls.push(normalized.href);
      }
    }

    // At this stage, we know that either `guids` is not-empty
    // or `urls` is not-empty.

    if (onResult && typeof onResult != "function") {
      throw new TypeError("Invalid function: " + onResult);
    }

    return Task.spawn(function* () {
      let removedPages = false;
      let count = 0;
      while (guids.length || urls.length) {
        if (count && count % 2 == 0) {
          // Every few cycles, yield time back to the main
          // thread to avoid jank.
          yield Promise.resolve();
        }
        count++;
        let guidsSlice = guids.splice(0, REMOVE_PAGES_CHUNKLEN);
        let urlsSlice = [];
        if (guidsSlice.length < REMOVE_PAGES_CHUNKLEN) {
          urlsSlice = urls.splice(0, REMOVE_PAGES_CHUNKLEN - guidsSlice.length);
        }

        let pages = {guids: guidsSlice, urls: urlsSlice};

        let result =
          yield PlacesUtils.withConnectionWrapper("History.jsm: remove",
                                                  db => remove(db, pages, onResult));

        removedPages = removedPages || result;
      }
      return removedPages;
    });
  },

  /**
   * Remove visits matching specific characteristics.
   *
   * Any change may be observed through nsINavHistoryObserver.
   *
   * @param filter: (object)
   *      The `object` may contain some of the following
   *      properties:
   *          - beginDate: (Date) Remove visits that have
   *                been added since this date (inclusive).
   *          - endDate: (Date) Remove visits that have
   *                been added before this date (inclusive).
   *          - limit: (Number) Limit the number of visits
   *                we remove to this number
   *          - url: (URL) Only remove visits to this URL
   *      If both `beginDate` and `endDate` are specified,
   *      visits between `beginDate` (inclusive) and `end`
   *      (inclusive) are removed.
   *
   * @param onResult: (function(VisitInfo), [optional])
   *     A callback invoked for each visit found and removed.
   *     Note that the referrer property of `VisitInfo`
   *     is NOT populated.
   *
   * @return (Promise)
   * @resolve (bool)
   *      `true` if at least one visit was removed, `false`
   *      otherwise.
   * @throws (TypeError)
   *      If `filter` does not have the expected type, in
   *      particular if the `object` is empty.
   */
  removeVisitsByFilter(filter, onResult = null) {
    if (!filter || typeof filter != "object") {
      throw new TypeError("Expected a filter");
    }

    let hasBeginDate = "beginDate" in filter;
    let hasEndDate = "endDate" in filter;
    let hasURL = "url" in filter;
    let hasLimit = "limit" in filter;
    if (hasBeginDate) {
      this.ensureDate(filter.beginDate);
    }
    if (hasEndDate) {
      this.ensureDate(filter.endDate);
    }
    if (hasBeginDate && hasEndDate && filter.beginDate > filter.endDate) {
      throw new TypeError("`beginDate` should be at least as old as `endDate`");
    }
    if (!hasBeginDate && !hasEndDate && !hasURL && !hasLimit) {
      throw new TypeError("Expected a non-empty filter");
    }

    if (hasURL && !(filter.url instanceof URL) && typeof filter.url != "string" &&
        !(filter.url instanceof Ci.nsIURI)) {
      throw new TypeError("Expected a valid URL for `url`");
    }

    if (hasLimit &&
        (typeof filter.limit != "number" ||
         filter.limit <= 0 ||
         !Number.isInteger(filter.limit))) {
      throw new TypeError("Expected a non-zero positive integer as a limit");
    }

    if (onResult && typeof onResult != "function") {
      throw new TypeError("Invalid function: " + onResult);
    }

    return PlacesUtils.withConnectionWrapper("History.jsm: removeVisitsByFilter",
      db => removeVisitsByFilter(db, filter, onResult)
    );
  },

  /**
   * Remove pages from the database based on a filter.
   *
   * Any change may be observed through nsINavHistoryObserver
   *
   *
   * @param filter: An object containing a non empty subset of the following
   * properties:
   * - host: (string)
   *     Hostname with subhost wildcard (at most one *), or empty for local files.
   *     The * can be used only if it is the first character in the url, and not the host.
   *     For example, *.mozilla.org is allowed, *.org, www.*.org or * is not allowed.
   * - beginDate: (Date)
   *     The first time the page was visited (inclusive)
   * - endDate: (Date)
   *     The last time the page was visited (inclusive)
   * @param [optional] onResult: (function(PageInfo))
   *      A callback invoked for each page found.
   *
   * @note This removes pages with at least one visit inside the timeframe.
   *       Any visits outside the timeframe will also be removed with the page.
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolve (bool)
   *      `true` if at least one page was removed, `false` otherwise.
   * @throws (TypeError)
   *       if `filter` does not have the expected type, in particular
   *       if the `object` is empty, or its components do not satisfy the
   *       criteria given above
   */
  removeByFilter(filter, onResult) {
    if (!filter || typeof filter !== "object") {
      throw new TypeError("Expected a filter object");
    }

    let hasHost = "host" in filter;
    if (hasHost) {
      if (typeof filter.host !== "string") {
        throw new TypeError("`host` should be a string");
      }
      filter.host = filter.host.toLowerCase();
    }

    let hasBeginDate = "beginDate" in filter;
    if (hasBeginDate) {
      this.ensureDate(filter.beginDate);
    }

    let hasEndDate = "endDate" in filter;
    if (hasEndDate) {
      this.ensureDate(filter.endDate);
    }

    if (hasBeginDate && hasEndDate && filter.beginDate > filter.endDate) {
      throw new TypeError("`beginDate` should be at least as old as `endDate`");
    }

    if (!hasBeginDate && !hasEndDate && !hasHost) {
      throw new TypeError("Expected a non-empty filter");
    }

    // Host should follow one of these formats
    // The first one matches `localhost` or any other custom set in hostsfile
    // The second one matches *.mozilla.org or mozilla.com etc
    // The third one is for local files
    if (hasHost &&
        !((/^[a-z0-9-]+$/).test(filter.host)) &&
        !((/^(\*\.)?([a-z0-9-]+)(\.[a-z0-9-]+)+$/).test(filter.host)) &&
        (filter.host !== "")) {
      throw new TypeError("Expected well formed hostname string for `host` with atmost 1 wildcard.");
    }

    if (onResult && typeof onResult != "function") {
      throw new TypeError("Invalid function: " + onResult);
    }

    return PlacesUtils.withConnectionWrapper(
      "History.jsm: removeByFilter",
      db => removeByFilter(db, filter, onResult)
    );
  },

  /**
   * Determine if a page has been visited.
   *
   * @param pages: (URL or nsIURI)
   *      The full URI of the page.
   *            or (string)
   *      The full URI of the page or the GUID of the page.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   * @resolve (bool)
   *      `true` if the page has been visited, `false` otherwise.
   * @throws (Error)
   *      If `pages` has an unexpected type or if a string provided
   *      is neither not a valid GUID nor a valid URI.
   */
  hasVisits(page, onResult) {
    throw new Error("Method not implemented");
  },

  /**
   * Clear all history.
   *
   * @return (Promise)
   *      A promise resolved once the operation is complete.
   */
  clear() {
    return PlacesUtils.withConnectionWrapper("History.jsm: clear",
      clear
    );
  },

  /**
   * Is a value a valid transition type?
   *
   * @param transitionType: (String)
   * @return (Boolean)
   */
  isValidTransition(transitionType) {
    return Object.values(History.TRANSITIONS).includes(transitionType);
  },

  /**
   * Throw if an object is not a Date object.
   */
  ensureDate(arg) {
    if (!arg || typeof arg != "object" || arg.constructor.name != "Date") {
      throw new TypeError("Expected a Date, got " + arg);
    }
  },

  /**
   * Possible values for the `transition` property of `VisitInfo`
   * objects.
   */

  TRANSITIONS: {
    /**
     * The user followed a link and got a new toplevel window.
     */
    LINK: Ci.nsINavHistoryService.TRANSITION_LINK,

    /**
     * The user typed the page's URL in the URL bar or selected it from
     * URL bar autocomplete results, clicked on it from a history query
     * (from the History sidebar, History menu, or history query in the
     * personal toolbar or Places organizer.
     */
    TYPED: Ci.nsINavHistoryService.TRANSITION_TYPED,

    /**
     * The user followed a bookmark to get to the page.
     */
    BOOKMARK: Ci.nsINavHistoryService.TRANSITION_BOOKMARK,

    /**
     * Some inner content is loaded. This is true of all images on a
     * page, and the contents of the iframe. It is also true of any
     * content in a frame if the user did not explicitly follow a link
     * to get there.
     */
    EMBED: Ci.nsINavHistoryService.TRANSITION_EMBED,

    /**
     * Set when the transition was a permanent redirect.
     */
    REDIRECT_PERMANENT: Ci.nsINavHistoryService.TRANSITION_REDIRECT_PERMANENT,

    /**
     * Set when the transition was a temporary redirect.
     */
    REDIRECT_TEMPORARY: Ci.nsINavHistoryService.TRANSITION_REDIRECT_TEMPORARY,

    /**
     * Set when the transition is a download.
     */
    DOWNLOAD: Ci.nsINavHistoryService.TRANSITION_DOWNLOAD,

    /**
     * The user followed a link and got a visit in a frame.
     */
    FRAMED_LINK: Ci.nsINavHistoryService.TRANSITION_FRAMED_LINK,

    /**
     * The user reloaded a page.
     */
    RELOAD: Ci.nsINavHistoryService.TRANSITION_RELOAD,
  },
});

/**
 * Convert a PageInfo object into the format expected by updatePlaces.
 *
 * Note: this assumes that the PageInfo object has already been validated
 * via PlacesUtils.validatePageInfo.
 *
 * @param pageInfo: (PageInfo)
 * @return (info)
 */
function convertForUpdatePlaces(pageInfo) {
  let info = {
    uri: PlacesUtils.toURI(pageInfo.url),
    title: pageInfo.title,
    visits: [],
  };

  for (let inVisit of pageInfo.visits) {
    let visit = {
      visitDate: PlacesUtils.toPRTime(inVisit.date),
      transitionType: inVisit.transition,
      referrerURI: (inVisit.referrer) ? PlacesUtils.toURI(inVisit.referrer) : undefined,
    };
    info.visits.push(visit);
  }
  return info;
}

/**
 * Convert a list of strings or numbers to its SQL
 * representation as a string.
 */
function sqlList(list) {
  return list.map(JSON.stringify).join();
}

/**
 * Invalidate and recompute the frecency of a list of pages,
 * informing frecency observers.
 *
 * @param db: (Sqlite connection)
 * @param idList: (Array)
 *      The `moz_places` identifiers for the places to invalidate.
 * @return (Promise)
 */
var invalidateFrecencies = Task.async(function*(db, idList) {
  if (idList.length == 0) {
    return;
  }
  let ids = sqlList(idList);
  yield db.execute(
    `UPDATE moz_places
     SET frecency = NOTIFY_FRECENCY(
       CALCULATE_FRECENCY(id), url, guid, hidden, last_visit_date
     ) WHERE id in (${ ids })`
  );
  yield db.execute(
    `UPDATE moz_places
     SET hidden = 0
     WHERE id in (${ ids })
     AND frecency <> 0`
  );
});

// Inner implementation of History.clear().
var clear = Task.async(function* (db) {
  // Remove all history.
  yield db.execute("DELETE FROM moz_historyvisits");

  // Clear the registered embed visits.
  PlacesUtils.history.clearEmbedVisits();

  // Expiration will take care of orphans.
  let observers = PlacesUtils.history.getObservers();
  notify(observers, "onClearHistory");

  // Invalidate frecencies for the remaining places. This must happen
  // after the notification to ensure it runs enqueued to expiration.
  yield db.execute(
    `UPDATE moz_places SET frecency =
     (CASE
      WHEN url_hash BETWEEN hash("place", "prefix_lo") AND
                            hash("place", "prefix_hi")
      THEN 0
      ELSE -1
      END)
     WHERE frecency > 0`);

  // Notify frecency change observers.
  notify(observers, "onManyFrecenciesChanged");
});

/**
 * Clean up pages whose history has been modified, by either
 * removing them entirely (if they are marked for removal,
 * typically because all visits have been removed and there
 * are no more foreign keys such as bookmarks) or updating
 * their frecency (otherwise).
 *
 * @param db: (Sqlite connection)
 *      The database.
 * @param pages: (Array of objects)
 *      Pages that have been touched and that need cleaning up.
 *      Each object should have the following properties:
 *          - id: (number) The `moz_places` identifier for the place.
 *          - hasVisits: (boolean) If `true`, there remains at least one
 *              visit to this page, so the page should be kept and its
 *              frecency updated.
 *          - hasForeign: (boolean) If `true`, the page has at least
 *              one foreign reference (i.e. a bookmark), so the page should
 *              be kept and its frecency updated.
 * @return (Promise)
 */
var cleanupPages = Task.async(function*(db, pages) {
  yield invalidateFrecencies(db, pages.filter(p => p.hasForeign || p.hasVisits).map(p => p.id));

  let pageIdsToRemove = pages.filter(p => !p.hasForeign && !p.hasVisits).map(p => p.id);
  if (pageIdsToRemove.length > 0) {
    let idsList = sqlList(pageIdsToRemove);
    // Note, we are already in a transaction, since callers create it.
    // Check relations regardless, to avoid creating orphans in case of
    // async race conditions.
    yield db.execute(`DELETE FROM moz_places WHERE id IN ( ${ idsList } )
                      AND foreign_count = 0 AND last_visit_date ISNULL`);
    // Hosts accumulated during the places delete are updated through a trigger
    // (see nsPlacesTriggers.h).
    yield db.executeCached(`DELETE FROM moz_updatehosts_temp`);

    // Expire orphans.
    yield db.executeCached(`DELETE FROM moz_pages_w_icons
                            WHERE page_url_hash NOT IN (SELECT url_hash FROM moz_places)`);
    yield db.executeCached(`DELETE FROM moz_icons
                            WHERE root = 0 AND id NOT IN (SELECT icon_id FROM moz_icons_to_pages)`);
    yield db.execute(`DELETE FROM moz_annos
                      WHERE place_id IN ( ${ idsList } )`);
    yield db.execute(`DELETE FROM moz_inputhistory
                      WHERE place_id IN ( ${ idsList } )`);
  }
});

/**
 * Notify observers that pages have been removed/updated.
 *
 * @param db: (Sqlite connection)
 *      The database.
 * @param pages: (Array of objects)
 *      Pages that have been touched and that need cleaning up.
 *      Each object should have the following properties:
 *          - id: (number) The `moz_places` identifier for the place.
 *          - hasVisits: (boolean) If `true`, there remains at least one
 *              visit to this page, so the page should be kept and its
 *              frecency updated.
 *          - hasForeign: (boolean) If `true`, the page has at least
 *              one foreign reference (i.e. a bookmark), so the page should
 *              be kept and its frecency updated.
 * @return (Promise)
 */
var notifyCleanup = Task.async(function*(db, pages) {
  let notifiedCount = 0;
  let observers = PlacesUtils.history.getObservers();

  let reason = Ci.nsINavHistoryObserver.REASON_DELETED;

  for (let page of pages) {
    let uri = NetUtil.newURI(page.url.href);
    let guid = page.guid;
    if (page.hasVisits) {
      // For the moment, we do not have the necessary observer API
      // to notify when we remove a subset of visits, see bug 937560.
      continue;
    }
    if (page.hasForeign) {
      // We have removed all visits, but the page is still alive, e.g.
      // because of a bookmark.
      notify(observers, "onDeleteVisits",
        [uri, /* last visit*/0, guid, reason, -1]);
    } else {
      // The page has been entirely removed.
      notify(observers, "onDeleteURI",
        [uri, guid, reason]);
    }
    if (++notifiedCount % NOTIFICATION_CHUNK_SIZE == 0) {
      // Every few notifications, yield time back to the main
      // thread to avoid jank.
      yield Promise.resolve();
    }
  }
});

/**
 * Notify an `onResult` callback of a set of operations
 * that just took place.
 *
 * @param data: (Array)
 *      The data to send to the callback.
 * @param onResult: (function [optional])
 *      If provided, call `onResult` with `data[0]`, `data[1]`, etc.
 *      Otherwise, do nothing.
 */
var notifyOnResult = Task.async(function*(data, onResult) {
  if (!onResult) {
    return;
  }
  let notifiedCount = 0;
  for (let info of data) {
    try {
      onResult(info);
    } catch (ex) {
      // Errors should be reported but should not stop the operation.
      Promise.reject(ex);
    }
    if (++notifiedCount % ONRESULT_CHUNK_SIZE == 0) {
      // Every few notifications, yield time back to the main
      // thread to avoid jank.
      yield Promise.resolve();
    }
  }
});

// Inner implementation of History.removeVisitsByFilter.
var removeVisitsByFilter = Task.async(function*(db, filter, onResult = null) {
  // 1. Determine visits that took place during the interval.  Note
  // that the database uses microseconds, while JS uses milliseconds,
  // so we need to *1000 one way and /1000 the other way.
  let conditions = [];
  let args = {};
  if ("beginDate" in filter) {
    conditions.push("v.visit_date >= :begin * 1000");
    args.begin = Number(filter.beginDate);
  }
  if ("endDate" in filter) {
    conditions.push("v.visit_date <= :end * 1000");
    args.end = Number(filter.endDate);
  }
  if ("limit" in filter) {
    args.limit = Number(filter.limit);
  }

  let optionalJoin = "";
  if ("url" in filter) {
    let url = filter.url;
    if (url instanceof Ci.nsIURI) {
      url = filter.url.spec;
    } else {
      url = new URL(url).href;
    }
    optionalJoin = `JOIN moz_places h ON h.id = v.place_id`;
    conditions.push("h.url_hash = hash(:url)", "h.url = :url");
    args.url = url;
  }


  let visitsToRemove = [];
  let pagesToInspect = new Set();
  let onResultData = onResult ? [] : null;

  yield db.executeCached(
     `SELECT v.id, place_id, visit_date / 1000 AS date, visit_type FROM moz_historyvisits v
             ${optionalJoin}
             WHERE ${ conditions.join(" AND ") }${ args.limit ? " LIMIT :limit" : "" }`,
     args,
     row => {
       let id = row.getResultByName("id");
       let place_id = row.getResultByName("place_id");
       visitsToRemove.push(id);
       pagesToInspect.add(place_id);

       if (onResult) {
         onResultData.push({
           date: new Date(row.getResultByName("date")),
           transition: row.getResultByName("visit_type")
         });
       }
     }
  );

  try {
    if (visitsToRemove.length == 0) {
      // Nothing to do
      return false;
    }

    let pages = [];
    yield db.executeTransaction(function*() {
      // 2. Remove all offending visits.
      yield db.execute(`DELETE FROM moz_historyvisits
                        WHERE id IN (${ sqlList(visitsToRemove) } )`);

      // 3. Find out which pages have been orphaned
      yield db.execute(
        `SELECT id, url, guid,
          (foreign_count != 0) AS has_foreign,
          (last_visit_date NOTNULL) as has_visits
         FROM moz_places
         WHERE id IN (${ sqlList([...pagesToInspect]) })`,
         null,
         row => {
           let page = {
             id:  row.getResultByName("id"),
             guid: row.getResultByName("guid"),
             hasForeign: row.getResultByName("has_foreign"),
             hasVisits: row.getResultByName("has_visits"),
             url: new URL(row.getResultByName("url")),
           };
           pages.push(page);
         });

      // 4. Clean up and notify
      yield cleanupPages(db, pages);
    });

    notifyCleanup(db, pages);
    notifyOnResult(onResultData, onResult); // don't wait
  } finally {
    // Ensure we cleanup embed visits, even if we bailed out early.
    PlacesUtils.history.clearEmbedVisits();
  }

  return visitsToRemove.length != 0;
});

// Inner implementation of History.removeByFilter
var removeByFilter = Task.async(function*(db, filter, onResult = null) {
  // 1. Create fragment for date filtration
  let dateFilterSQLFragment = "";
  let conditions = [];
  let params = {};
  if ("beginDate" in filter) {
    conditions.push("v.visit_date >= :begin");
    params.begin = PlacesUtils.toPRTime(filter.beginDate);
  }
  if ("endDate" in filter) {
    conditions.push("v.visit_date <= :end");
    params.end = PlacesUtils.toPRTime(filter.endDate);
  }

  if (conditions.length !== 0) {
    dateFilterSQLFragment =
      `EXISTS
         (SELECT id FROM moz_historyvisits v WHERE v.place_id = h.id AND
         ${ conditions.join(" AND ") }
         LIMIT 1)`;
  }

  // 2. Create fragment for host and subhost filtering
  let hostFilterSQLFragment = "";
  if (filter.host || filter.host === "") {
    // There are four cases that we need to consider,
    // mozilla.org, *.mozilla.org, localhost, and local files

    if (filter.host.indexOf("*") === 0) {
      // Case 1: subhost wildcard is specified (*.mozilla.org)
      let revHost = filter.host.slice(2).split("").reverse().join("");
      hostFilterSQLFragment =
        `h.rev_host between :revHostStart and :revHostEnd`;
      params.revHostStart = revHost + ".";
      params.revHostEnd = revHost + "/";
    } else {
      // This covers the rest (mozilla.org, localhost and local files)
      let revHost = filter.host.split("").reverse().join("") + ".";
      hostFilterSQLFragment =
        `h.rev_host = :hostName`;
      params.hostName = revHost;
    }
  }

  // 3. Find out what needs to be removed
  let fragmentArray = [hostFilterSQLFragment, dateFilterSQLFragment];
  let query =
      `SELECT h.id, url, rev_host, guid, title, frecency, foreign_count
       FROM moz_places h WHERE
       (${ fragmentArray.filter(f => f !== "").join(") AND (") })`;
  let onResultData = onResult ? [] : null;
  let pages = [];
  let hasPagesToRemove = false;

  yield db.executeCached(
    query,
    params,
    row => {
      let hasForeign = row.getResultByName("foreign_count") != 0;
      if (!hasForeign) {
        hasPagesToRemove = true;
      }
      let id = row.getResultByName("id");
      let guid = row.getResultByName("guid");
      let url = row.getResultByName("url");
      let page = {
        id,
        guid,
        hasForeign,
        hasVisits: false,
        url: new URL(url)
      };
      pages.push(page);
      if (onResult) {
        onResultData.push({
          guid,
          title: row.getResultByName("title"),
          frecency: row.getResultByName("frecency"),
          url: new URL(url)
        });
      }
    });

  if (pages.length === 0) {
    // Nothing to do
    return false;
  }

  try {
    yield db.executeTransaction(Task.async(function*() {
      // 4. Actually remove visits
      yield db.execute(`DELETE FROM moz_historyvisits
                        WHERE place_id IN(${ sqlList(pages.map(p => p.id)) })`);
      // 5. Clean up and notify
      yield cleanupPages(db, pages);
    }));

    notifyCleanup(db, pages);
    notifyOnResult(onResultData, onResult);
  } finally {
    PlacesUtils.history.clearEmbedVisits();
  }

  return hasPagesToRemove;
});

// Inner implementation of History.remove.
var remove = Task.async(function*(db, {guids, urls}, onResult = null) {
  // 1. Find out what needs to be removed
  let query =
    `SELECT id, url, guid, foreign_count, title, frecency
     FROM moz_places
     WHERE guid IN (${ sqlList(guids) })
        OR (url_hash IN (${ urls.map(u => "hash(" + JSON.stringify(u) + ")").join(",") })
            AND url IN (${ sqlList(urls) }))
    `;

  let onResultData = onResult ? [] : null;
  let pages = [];
  let hasPagesToRemove = false;
  yield db.execute(query, null, Task.async(function*(row) {
    let hasForeign = row.getResultByName("foreign_count") != 0;
    if (!hasForeign) {
      hasPagesToRemove = true;
    }
    let id = row.getResultByName("id");
    let guid = row.getResultByName("guid");
    let url = row.getResultByName("url");
    let page = {
      id,
      guid,
      hasForeign,
      hasVisits: false,
      url: new URL(url),
    };
    pages.push(page);
    if (onResult) {
      onResultData.push({
        guid,
        title: row.getResultByName("title"),
        frecency: row.getResultByName("frecency"),
        url: new URL(url)
      });
    }
  }));

  try {
    if (pages.length == 0) {
      // Nothing to do
      return false;
    }

    yield db.executeTransaction(function*() {
      // 2. Remove all visits to these pages.
      yield db.execute(`DELETE FROM moz_historyvisits
                        WHERE place_id IN (${ sqlList(pages.map(p => p.id)) })
                       `);

      // 3. Clean up and notify
      yield cleanupPages(db, pages);
    });

    notifyCleanup(db, pages);
    notifyOnResult(onResultData, onResult); // don't wait
  } finally {
    // Ensure we cleanup embed visits, even if we bailed out early.
    PlacesUtils.history.clearEmbedVisits();
  }

  return hasPagesToRemove;
});

/**
 * Merges an updateInfo object, as returned by asyncHistory.updatePlaces
 * into a PageInfo object as defined in this file.
 *
 * @param updateInfo: (Object)
 *      An object that represents a page that is generated by
 *      asyncHistory.updatePlaces.
 * @param pageInfo: (PageInfo)
 *      An PageInfo object into which to merge the data from updateInfo.
 *      Defaults to an empty object so that this method can be used
 *      to simply convert an updateInfo object into a PageInfo object.
 *
 * @return (PageInfo)
 *      A PageInfo object populated with data from updateInfo.
 */
function mergeUpdateInfoIntoPageInfo(updateInfo, pageInfo = {}) {
  pageInfo.guid = updateInfo.guid;
  if (!pageInfo.url) {
    pageInfo.url = new URL(updateInfo.uri.spec);
    pageInfo.title = updateInfo.title;
    pageInfo.visits = updateInfo.visits.map(visit => {
      return {
        date: PlacesUtils.toDate(visit.visitDate),
        transition: visit.transitionType,
        referrer: (visit.referrerURI) ? new URL(visit.referrerURI.spec) : null
      }
    });
  }
  return pageInfo;
}

// Inner implementation of History.insert.
var insert = Task.async(function*(db, pageInfo) {
  let info = convertForUpdatePlaces(pageInfo);

  return new Promise((resolve, reject) => {
    PlacesUtils.asyncHistory.updatePlaces(info, {
      handleError: error => {
        reject(error);
      },
      handleResult: result => {
        pageInfo = mergeUpdateInfoIntoPageInfo(result, pageInfo);
      },
      handleCompletion: () => {
        resolve(pageInfo);
      }
    });
  });
});

// Inner implementation of History.insertMany.
var insertMany = Task.async(function*(db, pageInfos, onResult, onError) {
  let infos = [];
  let onResultData = [];
  let onErrorData = [];

  for (let pageInfo of pageInfos) {
    let info = convertForUpdatePlaces(pageInfo);
    infos.push(info);
  }

  return new Promise((resolve, reject) => {
    PlacesUtils.asyncHistory.updatePlaces(infos, {
      handleError: (resultCode, result) => {
        let pageInfo = mergeUpdateInfoIntoPageInfo(result);
        onErrorData.push(pageInfo);
      },
      handleResult: result => {
        let pageInfo = mergeUpdateInfoIntoPageInfo(result);
        onResultData.push(pageInfo);
      },
      ignoreErrors: !onError,
      ignoreResults: !onResult,
      handleCompletion: (updatedCount) => {
        notifyOnResult(onResultData, onResult);
        notifyOnResult(onErrorData, onError);
        if (updatedCount > 0) {
          resolve();
        } else {
          reject({message: "No items were added to history."})
        }
      }
    }, true);
  });
});