gecko-dev/browser/components/sessionstore/SessionCookies.jsm

/* 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 = ["SessionCookies"];

const Cu = Components.utils;
const Ci = Components.interfaces;

Cu.import("resource://gre/modules/Services.jsm", this);
Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);

XPCOMUtils.defineLazyModuleGetter(this, "Utils",
  "resource://gre/modules/sessionstore/Utils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PrivacyLevel",
  "resource://gre/modules/sessionstore/PrivacyLevel.jsm");

// MAX_EXPIRY should be 2^63-1, but JavaScript can't handle that precision.
const MAX_EXPIRY = Math.pow(2, 62);

/**
 * The external API implemented by the SessionCookies module.
 */
this.SessionCookies = Object.freeze({
  collect() {
    return SessionCookiesInternal.collect();
  },

  restore(cookies) {
    SessionCookiesInternal.restore(cookies);
  }
});

/**
 * The internal API.
 */
var SessionCookiesInternal = {
  /**
   * Stores whether we're initialized, yet.
   */
  _initialized: false,

  /**
   * Retrieve an array of all stored session cookies.
   */
  collect() {
    this._ensureInitialized();
    return CookieStore.toArray();
  },

  /**
   * Restores a given list of session cookies.
   */
  restore(cookies) {
    for (let cookie of cookies) {
      let expiry = "expiry" in cookie ? cookie.expiry : MAX_EXPIRY;
      let cookieObj = {
        host: cookie.host,
        path: cookie.path || "",
        name: cookie.name || ""
      };

      let originAttributes = cookie.originAttributes || {};
      if (!Services.cookies.cookieExists(cookieObj, originAttributes)) {
        Services.cookies.add(cookie.host, cookie.path || "", cookie.name || "",
                             cookie.value, !!cookie.secure, !!cookie.httponly,
                             /* isSession = */ true, expiry, originAttributes);
      }
    }
  },

  /**
   * Handles observers notifications that are sent whenever cookies are added,
   * changed, or removed. Ensures that the storage is updated accordingly.
   */
  observe(subject, topic, data) {
    switch (data) {
      case "added":
        this._addCookie(subject);
        break;
      case "changed":
        this._updateCookie(subject);
        break;
      case "deleted":
        this._removeCookie(subject);
        break;
      case "cleared":
        CookieStore.clear();
        break;
      case "batch-deleted":
        this._removeCookies(subject);
        break;
      default:
        throw new Error("Unhandled cookie-changed notification.");
    }
  },

  /**
   * If called for the first time in a session, iterates all cookies in the
   * cookies service and puts them into the store if they're session cookies.
   */
  _ensureInitialized() {
    if (!this._initialized) {
      this._reloadCookies();
      this._initialized = true;
      Services.obs.addObserver(this, "cookie-changed");

      // Listen for privacy level changes to reload cookies when needed.
      Services.prefs.addObserver("browser.sessionstore.privacy_level", () => {
        this._reloadCookies();
      });
    }
  },

  /**
   * Adds a given cookie to the store.
   */
  _addCookie(cookie) {
    cookie.QueryInterface(Ci.nsICookie2);

    // Store only session cookies, obey the privacy level.
    if (cookie.isSession && PrivacyLevel.canSave(cookie.isSecure)) {
      CookieStore.add(cookie);
    }
  },

  /**
   * Updates a given cookie.
   */
  _updateCookie(cookie) {
    cookie.QueryInterface(Ci.nsICookie2);

    // Store only session cookies, obey the privacy level.
    if (cookie.isSession && PrivacyLevel.canSave(cookie.isSecure)) {
      CookieStore.add(cookie);
    } else {
      CookieStore.delete(cookie);
    }
  },

  /**
   * Removes a given cookie from the store.
   */
  _removeCookie(cookie) {
    cookie.QueryInterface(Ci.nsICookie2);

    if (cookie.isSession) {
      CookieStore.delete(cookie);
    }
  },

  /**
   * Removes a given list of cookies from the store.
   */
  _removeCookies(cookies) {
    for (let i = 0; i < cookies.length; i++) {
      this._removeCookie(cookies.queryElementAt(i, Ci.nsICookie2));
    }
  },

  /**
   * Iterates all cookies in the cookies service and puts them into the store
   * if they're session cookies. Obeys the user's chosen privacy level.
   */
  _reloadCookies() {
    CookieStore.clear();

    // Bail out if we're not supposed to store cookies at all.
    if (!PrivacyLevel.canSave(false)) {
      return;
    }

    let iter = Services.cookies.enumerator;
    while (iter.hasMoreElements()) {
      this._addCookie(iter.getNext());
    }
  }
};

/**
 * The internal storage that keeps track of session cookies.
 */
var CookieStore = {
  /**
   * The internal map holding all known session cookies.
   */
  _entries: new Map(),

  /**
   * Stores a given cookie.
   *
   * @param cookie
   *        The nsICookie2 object to add to the storage.
   */
  add(cookie) {
    let jscookie = {host: cookie.host, value: cookie.value};

    // Only add properties with non-default values to save a few bytes.
    if (cookie.path) {
      jscookie.path = cookie.path;
    }

    if (cookie.name) {
      jscookie.name = cookie.name;
    }

    if (cookie.isSecure) {
      jscookie.secure = true;
    }

    if (cookie.isHttpOnly) {
      jscookie.httponly = true;
    }

    if (cookie.expiry < MAX_EXPIRY) {
      jscookie.expiry = cookie.expiry;
    }

    if (cookie.originAttributes) {
      jscookie.originAttributes = cookie.originAttributes;
    }

    this._entries.set(this._getKeyForCookie(cookie), jscookie);
  },

  /**
   * Removes a given cookie.
   *
   * @param cookie
   *        The nsICookie2 object to be removed from storage.
   */
  delete(cookie) {
    this._entries.delete(this._getKeyForCookie(cookie));
  },

  /**
   * Removes all cookies.
   */
  clear() {
    this._entries.clear();
  },

  /**
   * Return all cookies as an array.
   */
  toArray() {
    return [...this._entries.values()];
  },

  /**
   * Returns the key needed to properly store and identify a given cookie.
   * A cookie is uniquely identified by the combination of its host, name,
   * path, and originAttributes properties.
   *
   * @param cookie
   *        The nsICookie2 object to compute a key for.
   * @return string
   */
  _getKeyForCookie(cookie) {
    return JSON.stringify({
      host: cookie.host,
      name: cookie.name,
      path: cookie.path,
      attr: ChromeUtils.originAttributesToSuffix(cookie.originAttributes)
    });
  }
};