/* 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/. */

Components.utils.import("resource://gre/modules/PlacesUtils.jsm");
Components.utils.import("resource://gre/modules/Services.jsm");
Components.utils.import("resource://gre/modules/AppConstants.jsm");

function Sanitizer() {}
Sanitizer.prototype = {
  // warning to the caller: this one may raise an exception (e.g. bug #265028)
  clearItem: function (aItemName)
  {
    if (this.items[aItemName].canClear)
      this.items[aItemName].clear();
  },

  canClearItem: function (aItemName)
  {
    return this.items[aItemName].canClear;
  },

  prefDomain: "",

  getNameFromPreference: function (aPreferenceName)
  {
    return aPreferenceName.substr(this.prefDomain.length);
  },

  /**
   * Deletes privacy sensitive data in a batch, according to user preferences
   *
   * @returns  null if everything's fine;  an object in the form
   *           { itemName: error, ... } on (partial) failure
   */
  sanitize: function ()
  {
    var branch = Services.prefs.getBranch(this.prefDomain);
    var errors = null;

    // Cache the range of times to clear
    if (this.ignoreTimespan)
      var range = null;  // If we ignore timespan, clear everything
    else
      range = this.range || Sanitizer.getClearRange();

    for (var itemName in this.items) {
      var item = this.items[itemName];
      item.range = range;
      if ("clear" in item && item.canClear && branch.getBoolPref(itemName)) {
        // Some of these clear() may raise exceptions (see bug #265028)
        // to sanitize as much as possible, we catch and store them,
        // rather than fail fast.
        // Callers should check returned errors and give user feedback
        // about items that could not be sanitized
        try {
          item.clear();
        } catch(er) {
          if (!errors)
            errors = {};
          errors[itemName] = er;
          dump("Error sanitizing " + itemName + ": " + er + "\n");
        }
      }
    }
    return errors;
  },

  // Time span only makes sense in certain cases.  Consumers who want
  // to only clear some private data can opt in by setting this to false,
  // and can optionally specify a specific range.  If timespan is not ignored,
  // and range is not set, sanitize() will use the value of the timespan
  // pref to determine a range
  ignoreTimespan : true,
  range : null,

  items: {
    cache: {
      clear: function ()
      {
        try {
          // Cache doesn't consult timespan, nor does it have the
          // facility for timespan-based eviction.  Wipe it.
          let cache = Components.classes["@mozilla.org/netwerk/cache-storage-service;1"]
                                .getService(Ci.nsICacheStorageService);
          cache.clear();
        } catch (ex) {}

      },

      get canClear()
      {
        return true;
      }
    },

    cookies: {
      clear: function ()
      {
        if (this.range) {
          // Iterate through the cookies and delete any created after our cutoff.
          var cookiesEnum = Services.cookies.enumerator;
          while (cookiesEnum.hasMoreElements()) {
            var cookie = cookiesEnum.getNext().QueryInterface(Ci.nsICookie2);

            if (cookie.creationTime > this.range[0])
              // This cookie was created after our cutoff, clear it
              Services.cookies.remove(cookie.host, cookie.name, cookie.path,
                                      cookie.originAttributes, false);
          }
        }
        else {
          // Remove everything
          Services.cookies.removeAll();
        }

        // Clear plugin data.
        const phInterface = Ci.nsIPluginHost;
        const FLAG_CLEAR_ALL = phInterface.FLAG_CLEAR_ALL;
        let ph = Cc["@mozilla.org/plugin/host;1"].getService(phInterface);

        // Determine age range in seconds. (-1 means clear all.) We don't know
        // that this.range[1] is actually now, so we compute age range based
        // on the lower bound. If this.range results in a negative age, do
        // nothing.
        let age = this.range ? (Date.now() / 1000 - this.range[0] / 1000000)
                             : -1;
        if (!this.range || age >= 0) {
          let tags = ph.getPluginTags();
          for (let i = 0; i < tags.length; i++) {
            try {
              ph.clearSiteData(tags[i], null, FLAG_CLEAR_ALL, age);
            } catch (e) {
              // If the plugin doesn't support clearing by age, clear everything.
              if (e.result == Components.results.
                    NS_ERROR_PLUGIN_TIME_RANGE_NOT_SUPPORTED) {
                try {
                  ph.clearSiteData(tags[i], null, FLAG_CLEAR_ALL, -1);
                } catch (e) {
                  // Ignore errors from the plugin
                }
              }
            }
          }
        }

        // clear any network geolocation provider sessions
        try {
            var branch = Services.prefs.getBranch("geo.wifi.access_token.");
            branch.deleteBranch("");
        } catch (e) {}

      },

      get canClear()
      {
        return true;
      }
    },

    history: {
      clear: function ()
      {
        if (this.range)
          PlacesUtils.history.removeVisitsByTimeframe(this.range[0], this.range[1]);
        else
          PlacesUtils.history.clear();

        try {
          var os = Components.classes["@mozilla.org/observer-service;1"]
                             .getService(Components.interfaces.nsIObserverService);
          os.notifyObservers(null, "browser:purge-session-history", "");
        } catch (e) { }

        try {
          var predictor = Components.classes["@mozilla.org/network/predictor;1"]
                                    .getService(Components.interfaces.nsINetworkPredictor);
          predictor.reset();
        } catch (e) { }
      },

      get canClear()
      {
        // bug 347231: Always allow clearing history due to dependencies on
        // the browser:purge-session-history notification. (like error console)
        return true;
      }
    },
  }
};

// "Static" members
Sanitizer.prefDomain          = "privacy.sanitize.";
Sanitizer.prefShutdown        = "sanitizeOnShutdown";
Sanitizer.prefDidShutdown     = "didShutdownSanitize";

// Time span constants corresponding to values of the privacy.sanitize.timeSpan
// pref.  Used to determine how much history to clear, for various items
Sanitizer.TIMESPAN_EVERYTHING = 0;
Sanitizer.TIMESPAN_HOUR       = 1;
Sanitizer.TIMESPAN_2HOURS     = 2;
Sanitizer.TIMESPAN_4HOURS     = 3;
Sanitizer.TIMESPAN_TODAY      = 4;

// Return a 2 element array representing the start and end times,
// in the uSec-since-epoch format that PRTime likes.  If we should
// clear everything, return null.  Use ts if it is defined; otherwise
// use the timeSpan pref.
Sanitizer.getClearRange = function (ts) {
  if (ts === undefined)
    ts = Sanitizer.prefs.getIntPref("timeSpan");
  if (ts === Sanitizer.TIMESPAN_EVERYTHING)
    return null;

  // PRTime is microseconds while JS time is milliseconds
  var endDate = Date.now() * 1000;
  switch (ts) {
    case Sanitizer.TIMESPAN_HOUR :
      var startDate = endDate - 3600000000; // 1*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_2HOURS :
      startDate = endDate - 7200000000; // 2*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_4HOURS :
      startDate = endDate - 14400000000; // 4*60*60*1000000
      break;
    case Sanitizer.TIMESPAN_TODAY :
      var d = new Date();  // Start with today
      d.setHours(0);      // zero us back to midnight...
      d.setMinutes(0);
      d.setSeconds(0);
      startDate = d.valueOf() * 1000; // convert to epoch usec
      break;
    default:
      throw "Invalid time span for clear private data: " + ts;
  }
  return [startDate, endDate];
};

Sanitizer._prefs = null;
Sanitizer.__defineGetter__("prefs", function()
{
  return Sanitizer._prefs ? Sanitizer._prefs
    : Sanitizer._prefs = Services.prefs
                                 .getBranch(Sanitizer
                                 .prefDomain);
});

// Shows sanitization UI
Sanitizer.showUI = function(aParentWindow)
{
  Services.ww.openWindow(AppConstants.platform == "macosx" ? null : aParentWindow,
                         "chrome://messenger/content/sanitize.xul",
                         "Sanitize",
                         "chrome,titlebar,dialog,centerscreen,modal",
                         null);
};

/**
 * Deletes privacy sensitive data in a batch, optionally showing the
 * sanitize UI, according to user preferences
 */
Sanitizer.sanitize = function(aParentWindow)
{
  Sanitizer.showUI(aParentWindow);
};

// this is called on startup and shutdown, to perform pending sanitizations
Sanitizer._checkAndSanitize = function()
{
  const prefs = Sanitizer.prefs;
  if (prefs.getBoolPref(Sanitizer.prefShutdown) &&
      !prefs.prefHasUserValue(Sanitizer.prefDidShutdown)) {
    // this is a shutdown or a startup after an unclean exit
    var s = new Sanitizer();
    s.prefDomain = "privacy.clearOnShutdown.";
    s.sanitize() || // sanitize() returns null on full success
      prefs.setBoolPref(Sanitizer.prefDidShutdown, true);
  }
};


