root/trunk/chrome/content/dta/manager.js

/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is DownThemAll!
 *
 * The Initial Developers of the Original Code are Stefano Verna and Federico Parodi
 * Portions created by the Initial Developers are Copyright (C) 2004-2007
 * the Initial Developers. All Rights Reserved.
 *
 * Contributor(s):
 *    Stefano Verna <stefano.verna@gmail.com>
 *    Federico Parodi <f.parodi@tiscali.it>
 *    Nils Maier <MaierMan@web.de>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */
 
const NS_DTA = 'http://www.downthemall.net/properties#';
const NS_METALINKER = 'http://www.metalinker.org/';
 
 
const NS_ERROR_MODULE_NETWORK = 0x804B0000;
const NS_ERROR_BINDING_ABORTED = NS_ERROR_MODULE_NETWORK + 2;
const NS_ERROR_UNKNOWN_HOST = NS_ERROR_MODULE_NETWORK + 30;
const NS_ERROR_CONNECTION_REFUSED = NS_ERROR_MODULE_NETWORK + 13;
const NS_ERROR_NET_TIMEOUT = NS_ERROR_MODULE_NETWORK + 14;
const NS_ERROR_NET_RESET = NS_ERROR_MODULE_NETWORK + 20;

const Cc = Components.classes;
const Ci = Components.interfaces;

const Exception = Components.Exception;
const Construct = Components.Constructor;
function Serv(c, i) {
  return Cc[c].getService(i ? Ci[i] : null);
}

const BufferedOutputStream = Construct('@mozilla.org/network/buffered-output-stream;1', 'nsIBufferedOutputStream', 'init');
const BinaryOutputStream = Construct('@mozilla.org/binaryoutputstream;1', 'nsIBinaryOutputStream', 'setOutputStream');
const BinaryInputStream = Construct('@mozilla.org/binaryinputstream;1', 'nsIBinaryInputStream', 'setInputStream');
const FileInputStream = Construct('@mozilla.org/network/file-input-stream;1', 'nsIFileInputStream', 'init');
const StringInputStream = Construct('@mozilla.org/io/string-input-stream;1', 'nsIStringInputStream', 'setData');

const ContentHandling = Serv('@downthemall.net/contenthandling;1', 'dtaIContentHandling');
const MimeService = Serv('@mozilla.org/uriloader/external-helper-app-service;1', 'nsIMIMEService');
const ObserverService = Serv('@mozilla.org/observer-service;1', 'nsIObserverService');
const WindowWatcherService = Serv('@mozilla.org/embedcomp/window-watcher;1', 'nsIWindowWatcher');

const MIN_CHUNK_SIZE = 512 * 1024;

// ammount to buffer in BufferedOutputStream
// furthermore up to this ammount will automagically discared after crashes
const CHUNK_BUFFER_SIZE = 96 * 1024;

// in use by chunk.writer...
// in use by decompressor... beware, actual size might be more than twice as big!
const MAX_BUFFER_SIZE = 5 * 1024 * 1024;
const MIN_BUFFER_SIZE = 1 * 1024 * 1024;

const REFRESH_FREQ = 1000;
const REFRESH_NFREQ = 1000 / REFRESH_FREQ;
const STREAMS_FREQ = 200;

var Dialog = {
  _observes: [
    'quit-application-requested',
    'quit-application-granted',
    'network:offline-status-changed'
  ],
  _initialized: false,
  _offline: false,
  get offline() {
    return this._offline;
  },
  set offline(nv) {
    this._offline = !!nv;
    let de = $('downloads');
    
    if (this._offline) {
      de.setAttribute('offline', true);
    }
    else if (de.hasAttribute('offline')) {
        de.removeAttribute('offline');
    }   
    Tree.invalidate();
  },
  _wasRunning: false,
  _lastTime: Utils.getTimestamp(),
  _running: [],
  _autoClears: [],
  completed: 0,
  totalbytes: 0,
  init: function D_init() {
    Tree.init($("downloads"));
    SessionManager.init();

    try {
      let ios2 = Serv('@mozilla.org/network/io-service;1', 'nsIIOService2');
      this.offline = ios2.offline;
    }
    catch (ex) {
      Debug.log("Cannot get offline status", ex);
    }
    
    makeObserver(this);
    this._observes.forEach(
      function(topic) {
        ObserverService.addObserver(this, topic, true);
      },
      this
    );
      
    document.getElementById("dtaHelp").hidden = !("openHelp" in window);
  
  
    if ("arguments" in window) {
      startDownloads(window.arguments[0], window.arguments[1]);
    }

    Tree.invalidate();
    this._initialized = true;
    for (let d in Tree.all) {
      if (d.is(FINISHING)) {
        this.run(d);
      }
    }
    this._updTimer = new Timer("Dialog.checkDownloads();", REFRESH_FREQ, true, true);
    new Timer("Dialog.refreshWritten();", 100, true, true);
    new Timer("Dialog.saveRunning();", 10000, true);
  },
  observe: function D_observe(subject, topic, data) {
    if (topic == 'quit-application-requested') {
      if (!this._canClose()) {
        delete this._forceClose;
        try {
          let cancelQuit = subject.QueryInterface(Ci.nsISupportsPRBool);
          cancelQuit.data = true;
        }
        catch (ex) {
          Debug.log("cannot set cancelQuit", ex);
        }
      }
    }
    else if (topic == 'quit-application-granted') {
      this._forceClose = true;
    }
    else if (topic == 'network:offline-status-changed') {
      this.offline = data == "offline";
    }
  },
  refresh: function D_refresh() {
    try {
      let sum = 0;
      const now = Utils.getTimestamp();
      this._running.forEach(
        function(i) {
          let d = i.d;
          
          let advanced = (d.partialSize - i.lastBytes);
          sum += advanced;
          
          let elapsed = (now - i.lastTime) / 1000;          
          if (elapsed < 1) {
            return;
          }           
          
          let speed = Math.round(advanced / elapsed);
          
          i.lastBytes = d.partialSize;
          i.lastTime = now;       

          // Refresh item speed
          d.speeds.push(speed > 0 ? speed : 0);
          if (d.speeds.length > SPEED_COUNT) {
            d.speeds.shift();
          }
          i.lastBytes = d.partialSize;
          i.lastTime = now;
          
          speed = 0;
          d.speeds.forEach(
            function(s) {
              speed += s;
            }
          );
          speed /= d.speeds.length;
          
          // Calculate estimated time         
          if (advanced != 0 && d.totalSize > 0) {
            let remaining = Math.ceil((d.totalSize - d.partialSize) / speed);
            if (!isFinite(remaining)) {
              d.status = _("unknown");
            }
            else {
              d.status = Utils.formatTimeDelta(remaining);
            }
          }
          d.speed = Utils.formatBytes(speed) + "/s";
        }
      );
      let elapsed = (now - this._lastTime) / 1000;
      this._lastTime = now;
      let speed = Math.round(sum * elapsed);
      speed = Utils.formatBytes((speed > 0) ? speed : 0);

      // Refresh status bar
      $("statusText").label = 
        _("cdownloads", [this.completed, Tree.rowCount])
        + " - "
        + _("cspeed")
        + " "
        + speed + "/s";

      // Refresh window title
      if (this._running.length == 1 && this._running[0].d.totalSize > 0) {
        document.title =
          this._running[0].d.percent
          + ' - '
          + this.completed + "/" + Tree.rowCount + " - "
          + speed + '/s - DownThemAll!';
      }
      else if (this._running.length > 0) {
        document.title =
          Math.floor(this.completed * 100 / Tree.rowCount) + '%'
          + ' - '       
          + this.completed + "/" + Tree.rowCount + " - "
          + speed + '/s - DownThemAll!';
      }
      else {
        document.title = this.completed + "/" + Tree.rowCount + " - DownThemAll!";
      }
    }
    catch(ex) {
      Debug.log("refresh():", ex);
    }
  },
  refreshWritten: function D_checkDownloads() {
    this._running.forEach(
      function(i) {
        i.d.invalidate();
      }
    );
  },
  saveRunning: function D_saveRunning() {
    if (!this._running.length) {
      return;
    }
    SessionManager.beginUpdate();
    this._running.forEach(
      function(i) {
        i.d.save();
      }
    );
    SessionManager.endUpdate();
  },

  checkDownloads: function D_checkDownloads() {
    try {
      this.refresh();
      
      this._running.forEach(
        function(i) {
          let d = i.d;
          // checks for timeout
          if (d.is(RUNNING) && (Utils.getTimestamp() - d.timeLastProgress) >= Prefs.timeout * 1000) {
            if (d.resumable || !d.totalSize || !d.partialSize) {
              d.pause();
              d.markAutoRetry();
              d.status = _("timeout");
            }
            else {
              d.cancel(_("timeout"));
            }
            Debug.logString(d + " is a timeout");
          }
        }
      )
      
      if (Prefs.autoClearComplete && this._autoClears.length) {
        Tree.remove(this._autoClears);
        this._autoClears = [];
      }

      if (!this._offline) {         
        if (Prefs.autoRetryInterval) {
          for (let d in Tree.all) {
            d.autoRetry();
          }
        }
        this.startNext();
      }
    }
    catch(ex) {
      Debug.log("checkDownloads():", ex);
    }
  },
  checkSameName: function D_checkSameName(download, path) {
    for each (let runner in this._running) {
      if (runner.d == download) {
        continue;
      }
      if (runner.d.destinationFile == path) {
        return true;
      }
    }
    return false;
  },
  startNext: function D_startNext() {
    try {
      var rv = false;
      for (let d in Tree.all) {
        if (this._running.length >= Prefs.maxInProgress) {
          return rv;
        }       
        if (!d.is(QUEUED)) {
          continue;
        }
        this.run(d);
        rv = true;
      }
      return rv;
    }
    catch(ex){
      Debug.log("startNext():", ex);
    }
    return false;
  },
  RunningJob: function(d) {
    this.d = d;
    this.lastBytes = d.partialSize;
    this.lastTime = Utils.getTimestamp();
  },
  run: function D_run(download) {
    download.status = _("starting");
    if (download.is(FINISHING) || (download.partialSize >= download.totalSize && download.totalSize)) {
      // we might encounter renaming issues;
      // but we cannot handle it because we don't know at which stage we crashed
      download.partialSize = download.totalSize;
      Debug.logString("Download seems to be complete; likely a left-over from a crash, finish it:" + download);
      download.finishDownload();
      return;
    }
    download.timeLastProgress = Utils.getTimestamp();
    download.timeStart = Utils.getTimestamp();
    download.state = RUNNING;
    if (!download.started) {
      download.started = true;
      Debug.logString("Let's start " + download);
    }
    else {
      Debug.logString("Let's resume " + download + " at " + download.partialSize);
    }
    this._running.push(new Dialog.RunningJob(download));
    download.resumeDownload();
  },
  wasStopped: function D_wasStopped(download) {
    this._running = this._running.filter(
      function(i) {
        if (i.d == download) {
          return false;
        }
        return true;
      },
      this
    );
  },
  signal: function D_signal(download) {
    download.save();
    if (download.is(RUNNING)) {
      this._wasRunning = true;
    }
    else if (Prefs.autoClearComplete && download.is(COMPLETE)) {
      this._autoClears.push(download);
    }
    if (!this._initialized || !this._wasRunning || !download.is(COMPLETE)) {
      return;
    }
    try {
      // check if there is something running or scheduled
      if (this.startNext() || Tree.some(function(d) { return d.is(FINISHING, RUNNING, QUEUED); } )) {
        return;
      }
      Debug.logString("signal(): Queue finished");
      Utils.playSound("done");
      
      let dp = Tree.at(0);
      if (dp) {
        dp = dp.destinationPath;
      }
      if (Prefs.alertingSystem == 1) {
        AlertService.show(_("dcom"), _('suc'), dp, dp);
      }
      else if (dp && Prefs.alertingSystem == 0) {
        if (confirm(_('suc') + "\n "+ _("folder")) == 1) {
          try {
            OpenExternal.launch(dp);
          }
          catch (ex){
            // no-op
          }
        }
      }
      if (Prefs.autoClose) {
        Dialog.close();
      }
    }
    catch(ex) {
      Debug.log("signal():", ex);
    }
  },
  _canClose: function D__canClose() {
    if (Tree.some(function(d) { return d.started && !d.resumable && d.is(RUNNING); })) {
      var rv = DTA_confirmYN(
        _("confclose"),
        _("nonres")
      );
      if (rv) {
        return false;
      }
    }
    return (this._forceClose = true);
  },
  close: function D_close() {
    Debug.logString("Close request");
    if (!this._forceClose && !this._canClose()) {
      delete this._forceClose;
      return false;
    }

    // stop everything!
    // enumerate everything we'll have to wait for!
    if (this._updTimer) {
      this._updTimer.kill();
      delete this._updTimer;
    }
    let chunks = 0;
    let finishing = 0;
    Tree.updateAll(
      function(d) {
        if (d.is(RUNNING, QUEUED)) {
          // enumerate all running chunks
          d.chunks.forEach(
            function(c) {
              if (c.running) {
                ++chunks;
              }
            },
            this
          );
          d.pause();        
        }
        else if (d.is(FINISHING)) {
          ++finishing;
        }
      },
      this
    );
    if (chunks || finishing) {
      if (this._safeCloseAttempts < 20) {
        ++this._safeCloseAttempts;
        new Timer(function() { Dialog.close(); }, 250);       
        return false;
      }
      Debug.logString("Going down even if queue was not probably closed yet!");
    }
    close();
    return true;
  },
  _cleanTmpDir: function D__cleanTmpDir() {
    if (!Prefs.tempLocation || Preferences.getMultiByteDTA("tempLocation", '') != '') {
      // cannot perform this action if we don't use a temp file
      // there might be far too many directories containing far too many tmpFiles.
      // or part files from other users.
      return;
    }
    let known = [];
    for (d in Tree.all) {
      known.push(d.tmpFile.leafName);
    }
    let tmpEnum = Prefs.tempLocation.directoryEntries;
    let unknown = []
    while (tmpEnum.hasMoreElements()) {
      let f = tmpEnum.getNext().QueryInterface(Ci.nsILocalFile);
      if (f.leafName.match(/\.dtapart$/) && known.indexOf(f.leafName) == -1) {
        unknown.push(f);
      }
    }
    unknown.forEach(
      function(f) {
        try {
          f.remove(false);
        }
        catch(ex) {
        }
      }
    );
  },
  _safeCloseAttempts: 0,

  unload: function D_unload() {
    TimerManager.killAll();
    Prefs.shutdown();
    try {
      this._cleanTmpDir();
    }
    catch(ex) {
      Debug.log("_safeClose", ex);
    }
    SessionManager.shutdown();
    return true;    
  }
};

function UrlManager(urls) {
  this._urls = [];
  this._idx = -1;

  if (urls instanceof Array) {
    this.initByArray(urls);
    this._hasFresh = this._urls.length != 0;
  }
  else if (urls) {
    throw "Feeding the UrlManager with some bad stuff is usually a bad idea!";
  }
}
UrlManager.prototype = {
  _sort: function(a,b) {
    const rv = b.preference - a.preference;
    return rv ? rv : (a.url < b.url ? -1 : 1);
  },
  initByArray: function um_initByArray(urls) {
    for each (let u in urls) {
      this.add(
        new DTA_URL(
          u.url,
          u.charset,
          u.usable,
          u.preference
        )
      );
    }
    this._urls.sort(this._sort);
    this._usable = this._urls[0].usable;
  },
  add: function um_add(url) {
    if (!url instanceof DTA_URL) {
      throw (url + " is not an DTA_URL");
    }
    if (!this._urls.some(function(ref) { return ref.url == url.url; })) {
      this._urls.push(url);
    }
  },
  getURL: function um_getURL(idx) {
    if (typeof(idx) != 'number') {
      this._idx++;
      if (this._idx >= this._urls.length) {
        this._idx = 0;
      }
      idx = this._idx;
    }
    return this._urls[idx];
  },
  get url() {
    return this._urls[0].url;
  },
  get usable() {
    return this._urls[0].usable;
  },
  get charset() {
    return this._urls[0].charset;
  },
  get length() {
    return this._urls.length;
  },
  get all() {
    for each (let i in this._urls) {
      yield i;
    }
  },
  markBad: function um_markBad(url) {
    if (this._urls.length > 1) {
      this._urls = this._urls.filter(function(u) { return u != url; });
    }
    else if (this._urls[0] == url) {
      return false;
    }
    return true;
  },
  toSource: function um_toSource() {
    let rv = [];
    this._urls.forEach(
      function(url) {
        rv.push({
          'url': url.url,
          'charset': url.charset,
          'usable': url.usable,
          'preference': url.preference
        });
      }
    );
    return rv;
  },
  toString: function() {
    let rv = '';
    this._urls.forEach(
      function(u) {
        rv += u.preference + " " + u.url + "\n";
      }
    );
    return rv;
  }
};
function Visitor() {
  // sanity check
  if (arguments.length != 1) {
    return;
  }

  var nodes = arguments[0];
  for (x in nodes) {
    if (!name || !(name in this.cmpKeys)) {
      continue;
    }
    this[x] = nodes[x];
  }
}

Visitor.prototype = {
  cmpKeys: {
    'etag': true, // must not be modified from 200 to 206: http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.2.7
    //'content-length': false,
    'content-type': true,
    'last-modified': true, // may get omitted later, but should not change
    'content-encoding': true // must not change, or download will become corrupt.
  },
  type: null,
  overrideCharset: null,
  encoding: null,
  fileName: null,
  acceptRanges: 'bytes',
  contentlength: 0,
  time: null,

  QueryInterface: function(aIID) {
    if (
      aIID.equals(Ci.nsISupports)
      || aIID.equals(Ci.nsIHttpHeaderVisitor)
    ) {
      return this;
    }
    throw Components.results.NS_ERROR_NO_INTERFACE;
  },
  visitHeader: function(aHeader, aValue) {
    try {
      const header = aHeader.toLowerCase();
      switch (header) {
        case 'content-type': {
          this.type = aValue;
          var ch = aValue.match(/charset=['"]?([\w\d_-]+)/i);
          if (ch && ch[1].length) {
            DTA_debug.logString("visitHeader: found override to " + ch[1]);
            this.overrideCharset = ch[1];
          }
        }
        break;

        case 'content-encoding':
          this.encoding = aValue;
        break;

        case 'accept-ranges':
          this.acceptRanges = aValue.toLowerCase().indexOf('none') == -1;
          Debug.logString("acceptrange = " + aValue.toLowerCase());
        break;

        case 'content-length':
          this.contentlength = Number(aValue);
        break;

        case 'content-range': {
          let cl = new Number(aValue.split('/').pop());
          if (cl > 0) {
            this.contentlength = cl;
          }
        }
        break;
        case 'last-modified':
          try {
            this.time = Utils.getTimestamp(aValue);
          }
          catch (ex) {
            Debug.log("gts", ex);
          }
        break;
      }
      if (header == 'etag') {
        // strip off the "inode"-part apache and others produce, as mirrors/caches usually provide different/wrong numbers here :p
        this[header] = aValue
          .replace(/^(?:[Ww]\/)?"(.+)"$/, '$1')
          .replace(/^[a-f\d]+-([a-f\d]+)-([a-f\d]+)$/, '$1-$2')
          .replace(/^([a-f\d]+):[a-f\d]{1,6}$/, '$1');
          Debug.logString("Etag: " + this[header] + " - " + aValue);
      }
      else if (header in this.cmpKeys) {
        this[header] = aValue;
      }
      if ((header == 'content-type' || header == 'content-disposition') && this.fileName == null) {
        let mhp = Serv('@mozilla.org/network/mime-hdrparam;1', 'nsIMIMEHeaderParam');
        let fn;
        try {
         fn = mhp.getParameter(aValue, 'filename', '', true, {});
        }
        catch (ex) {
          // no-op; handled below
        }
        if (!fn) {
          try {
           fn = mhp.getParameter(aValue, 'name', '', true, {});
          }
          catch (ex) {
            // no-op; handled below
          }
        }
        if (fn) {
          this.fileName = fn.getUsableFileName();
        }
      }
    }
    catch (ex) {
      Debug.log("hrhv::visitHeader:", ex);
    }
  },
  compare: function vi_compare(v) {
    if (!(v instanceof Visitor)) {
      return;
    }

    for (x in this.cmpKeys) {
      // we don't have this header
      if (!(x in this)) {
        continue;
      }
      // v does not have this header
      else if (!(x in v)) {
        // allowed to be missing?
        if (this.cmpKeys[x]) {
          continue;
        }
        Debug.logString(x + " missing");
        throw new Exception(x + " is missing");
      }
      // header is there, but differs
      else if (this[x] != v[x]) {
        Debug.logString(x + " nm: [" + this[x] + "] [" + v[x] + "]");
        throw new Exception("Header " + x + " doesn't match");
      }
    }
  },
  save: function vi_save(node) {
    var rv = {};
    // salva su file le informazioni sugli headers
    for (x in this.cmpKeys) {
      if (!(x in this)) {
        continue;
      }
      rv[x] = this[x];
    }
    return rv;
  }
};

/**
 * Visitor Manager c'tor
 * @author Nils
 */
function VisitorManager(nodes) {
  this._visitors = {};
  if (nodes) {
    this._load(nodes);
  }
}
VisitorManager.prototype = {
  /**
   * Loads a ::save'd JS Array
   * Will silently bypass failed items!
   * @author Nils
   */
  _load: function vm_init(nodes) {
    for each (let n in nodes) {
      try {
        this._visitors[n.url] = new Visitor(n.values);
      }
      catch (ex) {
        Debug.log("failed to read one visitor", ex);
      }
    }
  },
  /**
   * Saves/serializes the Manager and associated Visitors to an JS Array
   * @return A ::load compatible Array
   * @author Nils
   */
  toSource: function vm_toSource() {
    var rv = [];
    for (let x in this._visitors) {
      try {
        var v = {};
        v.url = x;
        v.values = this._visitors[x].save();
        rv.push(v);
      }
      catch(ex) {
        Debug.log(x, ex);
      }
    }
    return rv;
  },
  /**
   * Visit and compare a channel
   * @returns visitor for channel
   * @throws Exception if comparision yield a difference (i.e. channels are not "compatible")
   * @author Nils
   */
  visit: function vm_visit(chan) {
    var url = chan.URI.spec;

    var visitor = new Visitor();
    chan.visitResponseHeaders(visitor);
    if (url in this._visitors)
    {
        this._visitors[url].compare(visitor);
    }
    return (this._visitors[url] = visitor);
  },
  /**
   * return the first timestamp registered with a visitor
   * @throws Exception if no timestamp found
   * @author Nils
   */
  get time() {
    for (let i in this._visitors) {
      if (this._visitors[i].time > 0) {
        return this._visitors[i].time;
      }
    }
    throw new Exception("No Date registered");
  }
};

function QueueItem(lnk, dir, num, desc, mask, referrer, tmpFile) {

  this.visitors = new VisitorManager();

  this.startDate = new Date();  

  this.chunks = [];
  this.speeds = new Array();
  
}

QueueItem.prototype = {
  _state: QUEUED,
  get state() {
    return this._state;
  },
  set state(nv) {
    if (this._state != nv) {
      if (this._state == RUNNING) {
        // remove ourself from inprogresslist
        Dialog.wasStopped(this);
      }
      this._state = nv;
      this.invalidate();
      Tree.refreshTools();
      Dialog.signal(this);
    }
  },
  
  postData: null,
  
  _fileName: null,
  get fileName() {
    return this._fileName;
  },
  set fileName(nv) {
    this._fileName = nv;
    this.rebuildDestination();
    this.invalidate();
    return nv;
  },
  _description: null,
  get description() {
    return this._description;
  },
  set description(nv) {
    this._description = nv;
    this.rebuildDestination();
    this.invalidate();
    return nv;
  },  

  _pathName: null,
  get pathName() {
    return this._pathName;
  },
  set pathName(nv) {
    this._pathName = nv.toString();
    this.rebuildDestination();
    this.invalidate();
    return nv;
  },  

  _mask: null,
  get mask() {
    return this._mask;
  },
  set mask(nv) {
    this._mask = nv;
    this.rebuildDestination();
    this.invalidate();
    return nv;
  },    
  
  _destinationName: null,
  destinationNameOverride: null,
  _destinationNameFull: null,
  get destinationName() {
    return this._destinationNameFull; 
  },
  set destinationName(nv) {
    this.destinationNameOverride = nv;
    this.rebuildDestination();
    this.invalidate();
    return this._destinationNameFull;
  },
  
  _destinationFile: null,
  get destinationFile() {
    if (!this._destinationFile) {
      this.rebuildDestination();
    }
    return this._destinationFile;
  },
  
  _conflicts: 0,
  get conflicts() {
    return this._conflicts;
  },
  set conflicts(nv) {
    if (typeof(nv) != 'number') {
      return this._conflicts;
    }
    this._conflicts = nv;
    this.rebuildDestination();
    this.invalidate();
    return nv;
  },
  _tmpFile: null,
  get tmpFile() {
    if (!this._tmpFile) {
      var dest = Prefs.tempLocation
        ? Prefs.tempLocation.clone()
        : new FileFactory(this.destinationPath);
      let name = this.fileName;
      if (name.length > 60) {
        name = name.substring(0, 60);
      }
      dest.append(name + "-" + newUUIDString() + '.dtapart');
      this._tmpFile = dest;
    }
    return this._tmpFile;
  },
  _hash: null,
  get hash() {
    return this._hash;
  },
  set hash(nv) {
    this._hash = nv;
    this._prettyHash = this.hash ? _('prettyhash', [this.hash.type, this.hash.sum]) : _('nas');
  },
  _prettyHash: null,
  get prettyHash() {
    return this._prettyHash;
  },

  /**
   *Takes one or more state indicators and returns if this download is in state of any of them
   */
  is: function QI_is() {
    let state = this.state;
    for (let i = 0, e = arguments.length; i < e; ++i) {
      if (state == arguments[i]) {
        return true;
      }
    }
    return false;
  },
  
  save: function QI_save() {
    if (
      (Prefs.removeCompleted && this.is(COMPLETE))
      || (Prefs.removeCanceled && this.is(CANCELED))
      || (Prefs.removeAborted && this.is(PAUSED))
    ) {
      if (this.dbId) {
        this.remove();
      }
      return false;     
    }     
    if (this.dbId) {
      SessionManager.saveDownload(this.dbId, this.toSource());
      return true;
    }

    this.dbId = SessionManager.addDownload(this.toSource());
    return true;
  },
  remove: function QI_remove() {
    SessionManager.deleteDownload(this.dbId);
    delete this.dbId;
  },
  _position: -1,
  get position() {
    return this._position;
  },
  set position(nv) {
    if (nv == this._position) {
      return;
    }
    this._position = nv;
    if (this.dbId && this._position != -1) {
      SessionManager.savePosition(this.dbId, this._position); 
    }
  },

  contentType: "",
  visitors: null,
  _totalSize: 0,
  get totalSize() { return this._totalSize; },
  set totalSize(nv) {
    this._totalSize = nv;
    this.invalidate();
    return this._totalSize;
  },
  partialSize: 0,

  startDate: null,

  compression: null,

  resumable: true,
  started: false,

  _activeChunks: 0,
  get activeChunks() {
    return this._activeChunks;
  },
  set activeChunks(nv) {
    nv = Math.max(0, nv);
    this._activeChunks = nv;
    this.invalidate();
    return this._activeChunks;
  },
  _maxChunks: 0,
  get maxChunks() {
    if (!this._maxChunks) {
        this._maxChunks = Prefs.maxChunks;
    }
    return this._maxChunks;
  },
  set maxChunks(nv) {
    this._maxChunks = nv;
    if (this._maxChunks < this._activeChunks) {
      let running = this.chunks.filter(function(c) { return c.running; });
      while (running.length && this._maxChunks < running.length) {
        let c = running.pop();
        if (c.remainder < 10240) {
          continue;
        }
        c.cancel();
      }
    }
    else if (this._maxChunks > this._activeChunks && this.is(RUNNING)) {
      this.resumeDownload();
      
    }
    this.invalidate();
    Debug.logString("mc set to " + nv);
    return this._maxChunks;
  },
  timeLastProgress: 0,
  timeStart: 0,

  _icon: null,
  get icon() {
    if (!this._icon) {
      this._icon = getIcon(this.destinationName, 'metalink' in this);
    }
    return this._icon;
  },
  get largeIcon() {
    return getIcon(this.destinationName, 'metalink' in this, 32);
  },
  get size() {
    try {
      let file = new FileFactory(this.destinationFile);
      if (file.exists()) {
        return file.fileSize;
      }
    }
    catch (ex) {
      Debug.log("download::getSize(): ", e)
    }
    return 0;
  },
  get dimensionString() {
    if (this.partialSize <= 0) {
      return _('unknown'); 
    }
    else if (this.totalSize <= 0) {
      return _('transfered', [Utils.formatBytes(this.partialSize), _('nas')]);
    }
    else if (this.is(COMPLETE)) {
      return Utils.formatBytes(this.totalSize);
    }
    return _('transfered', [Utils.formatBytes(this.partialSize), Utils.formatBytes(this.totalSize)]);
  },
  _status : '',
  get status() {
    if (Dialog.offline && this.is(QUEUED, PAUSED)) {
      return _('offline');
    }
    return this._status + (this._autoRetryTime ? ' *' : '');
  },
  set status(nv) {
    if (nv != this._status) {
      this._status = nv;
      this.invalidate();
    }
    return this._status;
  },
  get parts() {
    if (this.maxChunks) {
      return (this.activeChunks) + '/' + this.maxChunks;
    }
    return '';
  },
  get percent() {
    if (!this.totalSize && this.is(RUNNING)) {
      return _('nas');
    }
    else if (!this.totalSize) {
      return "0%";
    }
    else if (this.is(COMPLETE)) {
      return "100%";
    }
    return Math.floor(this.partialSize / this.totalSize * 100) + "%";
  },
  _destinationPath: '',
  get destinationPath() {
    return this._destinationPath;
  },

  invalidate: function QI_invalidate() {
    Tree.invalidate(this);
  },

  safeRetry: function QI_safeRetry() {
    // reset flags
    this.totalSize = this.partialSize = 0;
    this.compression = null;
    this.activeChunks = this.maxChunks = 0;
    this.chunks.forEach(function(c) { c.cancel(); });
    this.chunks = [];
    this.speeds = [];
    this.visitors = new VisitorManager();
    Dialog.run(this);
  },

  refreshPartialSize: function QI_refreshPartialSize(){
    let size = 0;
    this.chunks.forEach(function(c) { size += c.written; });
    this.partialSize = size;
  },

  pause: function QI_pause(){
    if (this.chunks) {
      for each (let c in this.chunks) {
        if (c.running) {
          c.cancel();
        }
      }
    }
    this.activeChunks = 0;
    this.state = PAUSED;
    this.speeds = [];
  },

  moveCompleted: function QI_moveCompleted() {
    if (this.is(CANCELED)) {
      return;
    }
    ConflictManager.resolve(this, 'continueMoveCompleted');
  },
  continueMoveCompleted: function QI_continueMoveCompleted() {
    if (this.is(CANCELED)) {
      return;
    }   
    try {
      // safeguard against some failed chunks.
      this.chunks.forEach(function(c) { c.close(); });
      var destination = new FileFactory(this.destinationPath);
      Debug.logString(this.fileName + ": Move " + this.tmpFile.path + " to " + this.destinationFile);

      if (!destination.exists()) {
        destination.create(Ci.nsIFile.DIRECTORY_TYPE, Prefs.dirPermissions);
        this.invalidate();
      }
      var df = destination.clone();
      df.append(this.destinationName);
      if (df.exists()) {
        df.remove(false);
      }
      // move file
      if (this.compression) {
        DTA_include("dta/manager/decompressor.js");
        new Decompressor(this);
      }
      else {
        this.tmpFile.clone().moveTo(destination, this.destinationName);
        this.complete();
      }
    }
    catch(ex) {
      Debug.log("continueMoveCompleted encountered an error", ex);
      this.complete(ex);
    }
  },
  handleMetalink: function QI_handleMetaLink() {
    try {
      DTA_include("dta/manager/metalinker.js");
      Metalinker.handleDownload(this);
    }
    catch (ex) {
      Debug.log("handleMetalink", ex);
    }
  },
  verifyHash: function() {
    DTA_include("dta/manager/verificator.js");
    new Verificator(this);
  },
  customFinishEvent: function() {
    DTA_include("dta/manager/customevent.js");
    new CustomEvent(this, Prefs.finishEvent);
  },
  setAttributes: function() {
    if (Prefs.setTime) {
      try {
        var time = this.startDate.getTime();
        try {
          var time =  this.visitors.time;
        }
        catch (ex) {
          // no-op
        }
        // small validation. Around epoche? More than a month in future?
        if (time < 2 || time > Date.now() + 30 * 86400000) {
          throw new Exception("invalid date encountered: " + time + ", will not set it");
        }
        // have to unwrap
        var file = new FileFactory(this.destinationFile);
        file.lastModifiedTime = time;
      }
      catch (ex) {
        Debug.log("Setting timestamp on file failed: ", ex);
      }
    }
    this.totalSize = this.partialSize = this.size;
    ++Dialog.completed;
    
    this.complete();
  },
  finishDownload: function QI_finishDownload(exception) {
    Debug.logString("finishDownload, connections: " + this.sessionConnections);
    this._completeEvents = ['moveCompleted', 'setAttributes'];
    if (this.hash) {
      this._completeEvents.push('verifyHash');
    }
    if ('isMetalink' in this) {
      this._completeEvents.push('handleMetalink');
    }
    if (Prefs.finishEvent) {
      this._completeEvents.push('customFinishEvent');
    }
    this.complete();
  },
  _completeEvents: [],
  complete: function QI_complete(exception) {
    if (exception) {
      this.fail(_("accesserror"), _("permissions") + " " + _("destpath") + ". " + _("checkperm"), _("accesserror"));
      Debug.log("complete: ", exception);
      return;
    }
    if (this._completeEvents.length) {
      var evt = this._completeEvents.shift();
      var tp = this;
      window.setTimeout(
        function() {
          try {
            tp[evt]();
          }
          catch(ex) {
            Debug.log("completeEvent failed: " + evt, ex);
            tp.complete();
          }
        },
        0
      );
      return;
    }
    this.chunks = [];   
    this.activeChunks = 0;
    this.state = COMPLETE;
    this.status = _("complete");
  },
  rebuildDestination: function QI_rebuildDestination() {
    try {
      let uri = this.urlManager.usable.toURL();
      let host = uri.host.toString();

      // normalize slashes
      let mask = this.mask
        .normalizeSlashes()
        .removeLeadingSlash()
        .removeFinalSlash();

      let uripath = uri.path.removeLeadingChar("/");
      if (uripath.length) {
        uripath = uripath.substring(0, uri.path.lastIndexOf("/"))
          .normalizeSlashes()
          .removeFinalSlash();
      }

      let query = '';
      try {
        query = uri.query;
      }
      catch (ex) {
        // no-op
      }

      let description = this.description.removeBadChars().replaceSlashes(' ').trim();
      
      let name = this.fileName;
      let ext = name.getExtension();
      if (ext) {
        name = name.substring(0, name.length - ext.length - 1);

        if (this.contentType && /htm/.test(this.contentType) && !/htm/.test(ext)) {
          ext += ".html";
        }
      }
      // mime-service method
      else if (this.contentType && /^(?:image|text)/.test(this.contentType)) {
        try {
          let info = MimeService.getFromTypeAndExtension(this.contentType.split(';')[0], "");
          ext = info.primaryExtension;
        } catch (ex) {
          ext = '';
        }
      }
      else {
        name = this.fileName;
        ext = '';
      }
      let ref = this.referrer ? this.referrer.host.toString() : '';
      
      let curl = (uri.host + ((uripath=="") ? "" : (SYSTEMSLASH + uripath))); 
      
      var replacements = {
        "name": name,
        "ext": ext,
        "text": description,
        "url": host,
        "subdirs": uripath,
        "flatsubdirs": uripath.replaceSlashes('-'),
        "refer": ref,
        "qstring": query,
        "curl": curl,
        "flatcurl": curl.replaceSlashes('-'),
        "num": Utils.formatNumber(this.numIstance),
        "hh": Utils.formatNumber(this.startDate.getHours(), 2),
        "mm": Utils.formatNumber(this.startDate.getMinutes(), 2),
        "ss": Utils.formatNumber(this.startDate.getSeconds(), 2),
        "d": Utils.formatNumber(this.startDate.getDate(), 2),
        "m": Utils.formatNumber(this.startDate.getMonth() + 1, 2),
        "y": String(this.startDate.getFullYear())
      }
      function replacer(type) {
        var t = type.substr(1, type.length - 2);
        if (t in replacements) {
          return replacements[t];
        }
        return type;
      }
      
      mask = mask.replace(/\*\w+\*/gi, replacer);

      mask = mask.removeBadChars().removeFinalChar(".").trim().split(SYSTEMSLASH);
      let file = new FileFactory(this.pathName.addFinalSlash());
      while (mask.length) {
        file.append(mask.shift());
      }
      this._destinationName = file.leafName;
      this._destinationPath = file.parent.path;
    }
    catch(ex) {
      this._destinationName = this.fileName;
      this._destinationPath = this.pathName.addFinalSlash();
      Debug.log("rebuildDestination():", ex);
    }
    this._destinationNameFull = Utils.formatConflictName(
      this.destinationNameOverride ? this.destinationNameOverride : this._destinationName,
      this.conflicts
    );
    let file = new FileFactory(this.destinationPath);
    file.append(this.destinationName);
    this._destinationFile = file.path;
    this._icon = null;
  },

  fail: function QI_fail(title, msg, state) {
    Debug.logString("failDownload invoked");

    this.cancel(state);

    Utils.playSound("error");

    switch (Prefs.alertingSystem) {
      case 1:
        AlertService.show(title, msg, false);
        break;
      case 0:
        alert(msg);
        break;
    }
  },

  cancel: function QI_cancel(message) {
    try {
      if (this.is(CANCELED)) {
        return;
      }
      if (this.is(COMPLETE)) {
        Dialog.completed--;
      }
      else if (this.is(RUNNING)) {
        this.pause();
      }
      this.state = CANCELED;      
      Debug.logString(this.fileName + ": canceled");

      this.visitors = new VisitorManager();

      if (message == "" || !message) {
        message = _("canceled");
      }
      this.status = message;


      this.removeTmpFile();

      // gc
      this.chunks = [];
      this.totalSize = this.partialSize = 0;
      this.maxChunks = this.activeChunks = 0;
      this.conflicts = 0;
      this.resumable = true;
      this._autoRetries = 0;
      delete this._autoRetryTime;
      this.save();
    } catch(ex) {
      Debug.log("cancel():", ex);
    }
  },
  
  removeTmpFile: function QI_removeTmpFile() {
    if (!this.tmpFile.exists()) {
      return;
    }
    try {
      this.tmpFile.remove(false);
    }
    catch (ex) {
      Debug.log("failed to remove tmpfile: " + this.tmpFile.path, ex);
    }
  },
  sessionConnections: 0,
  _autoRetries: 0,
  _autoRetryTime: 0,
  get autoRetrying() {
    return !!this._autoRetryTime;
  },
  markAutoRetry: function QI_markRetry() {
    if (!Prefs.autoRetryInterval || (Prefs.maxAutoRetries && Prefs.maxAutoRetries <= this._autoRetries)) {
       return;
    }
    this._autoRetryTime = Utils.getTimestamp();
    Debug.logString("marked auto-retry: " + d);
  },
  autoRetry: function QI_autoRetry() {
    if (!this._autoRetryTime || Utils.getTimestamp() - (Prefs.autoRetryInterval * 1000) < this._autoRetryTime) {
      return;
    }

    this._autoRetryTime = 0;
    ++this._autoRetries;
    this.queue();
    Debug.logString("Requeued due to auto-retry: " + d);    
  },
  queue: function QI_queue() {
    this._autoRetryTime = 0;
    this.state = QUEUED;
    this.status = _("inqueue");
  },
  resumeDownload: function QI_resumeDownload() {
    Debug.logString("resumeDownload: " + this);
    function cleanChunks(d) {
      // merge finished chunks together, so that the scoreboard does not bloat that much
      for (let i = d.chunks.length - 2; i > -1; --i) {
        let c1 = d.chunks[i], c2 = d.chunks[i + 1];
        if (c1.complete && c2.complete) {
          c1.merge(c2);
          d.chunks.splice(i + 1, 1);
        }
      }
    }
    function downloadNewChunk(download, start, end, header) {
      var chunk = new Chunk(download, start, end);
      Debug.logString("started: " + chunk);
      download.chunks.push(chunk);
      download.chunks.sort(function(a,b) { return a.start - b.start; });
      downloadChunk(download, chunk, header);
      download.sessionConnctions = 0; 
    }
    function downloadChunk(download, chunk, header) {
      chunk.running = true;
      download.state = RUNNING;
      Debug.logString("started: " + chunk);
      chunk.download = new Connection(download, chunk, header);
      ++download.activeChunks;
      ++download.sessionConnections;
    }
    
    cleanChunks(this);

    try {
      if (this.maxChunks <= this.activeChunks) {
        return false;
      }

      var rv = false;

      // we didn't load up anything so let's start the main chunk (which will grab the info)
      if (this.chunks.length == 0) {
        downloadNewChunk(this, 0, 0, true);
        return false;
      }

      // start some new chunks
      var paused = this.chunks.filter(
        function (chunk) {
          return !(chunk.running || chunk.complete);
        }
      );
      while (this.activeChunks < this.maxChunks) {

        // restart paused chunks
        if (paused.length) {
          downloadChunk(this, paused.shift());
          rv = true;
          continue;
        }
        
        // find biggest chunk
        let biggest = null;
        this.chunks.forEach(
          function (chunk) {
            if (chunk.running && chunk.remainder > MIN_CHUNK_SIZE * 2) {
              if (!biggest || biggest.remainder < chunk.remainder) {
                biggest = chunk;
              }
            }
          }
        );

        // nothing found, break
        if (!biggest) {
          break;
        }
        var end = biggest.end;
        var bend = biggest.start + biggest.written + Math.floor(biggest.remainder / 2);
        biggest.end = bend;
        downloadNewChunk(this, biggest.end + 1, end);
        rv = true;
      }

      return rv;
    }
    catch(ex) {
      Debug.log("resumeDownload():", ex);
    }
    return false;
  },
  dumpScoreboard: function QI_dumpScoreboard() {
    let scoreboard = '';
    let len = String(this.totalSize).length; 
    this.chunks.forEach(
      function(c,i) {
        scoreboard += i
          + ": "
          + c
          + "\n";
      }
    );
    Debug.logString("scoreboard\n" + scoreboard);
  },  
  toString: function() {
    return this.urlManager.usable;
  },
  toSource: function() {
    let e = {};
    [
      'fileName',
      'postData',
      'numIstance',
      'description',
      'resumable',
      'mask',
      'pathName',
      'compression',
      'maxChunks',
      'contentType',
      'conflicts',
      'fromMetalink'
    ].forEach(
      function(u) {
        e[u] = this[u];
      },
      this
    );
    if (this.hash) {
      e.hash = _atos(this.hash.sum);
      e.hashType = _atos(this.hash.type);
    }
    e.state = this.is(COMPLETE, CANCELED, FINISHING) ? this.state : PAUSED;
    if (this.destinationNameOverride) {
      this.destinationName = this.destinationNameOverride;
    }
    if (this.referrer) {
      e.referrer = this.referrer.spec;
    }
    // Store this so we can later resume.
    if (!this.is(CANCELED, COMPLETE) && this.partialSize) {
      e.tmpFile = this.tmpFile.path;
    }
    e.startDate = this.startDate.getTime();

    e.urlManager = this.urlManager.toSource();
    e.visitors = this.visitors.toSource();

    if (!this.resumable && !this.is(COMPLETE)) {
      e.totalSize = 0;
    }
    else {
      e.totalSize = this.totalSize;
    }
    
    e.chunks = [];

    if (this.is(RUNNING, PAUSED, QUEUED) && this.resumable) {
      this.chunks.forEach(
        function(c) {
          e.chunks.push({start: c.start, end: c.end, written: c.safeBytes});
        }
      );
    }
    return Serializer.encode(e);
  }
}

function Chunk(download, start, end, written) {
  // saveguard against null or strings and such
  this._written = written > 0 ? written : 0;
  this._buffered = 0;
  this._start = start;
  this._end = end;
  this.end = end;
  this._parent = download;
  this._sessionbytes = 0;
}

Chunk.prototype = {
  running: false,
  get starter() {
    return this.end <= 0;
  },
  get start() {
    return this._start;
  },
  get end() {
    return this._end;
  },
  set end(nv) {
    this._end = nv;
    this._total = this._end - this._start + 1;
  },
  get total() {
    return this._total;
  },
  get written() {
    return this._written;
  },
  get safeBytes() {
    return this.written - this._buffered;
  },
  get remainder() {
    return this._total - this._written;
  },
  get complete() {
    if (this._end == -1) {
      return this.written != 0;
    }
    return this._total == this.written;
  },
  get parent() {
    return this._parent;
  },
  merge: function CH_merge(ch) {
    if (!this.complete && !ch.complete) {
      throw new Error("Cannot merge incomplete chunks this way!");
    }
    this.end = ch.end;
    this._written += ch._written;
  },
  open: function CH_open() {
    this._sessionBytes = 0;
    let file = this.parent.tmpFile.clone();
    if (!file.parent.exists()) {
      file.parent.create(Ci.nsIFile.DIRECTORY_TYPE, Prefs.dirPermissions);
      this.parent.invalidate();
    }
    let prealloc = !file.exists();
    if (prealloc && this.parent.totalSize > 0) {
      try {
        file.create(file.NORMAL_FILE_TYPE, Prefs.permissions);
        file.fileSize = this.parent.totalSize;
        Debug.logString("fileSize set using #1");
        prealloc = false;
      }
      catch (ex) {
        // no op
      }
    }   
    let outStream = new FileOutputStream(file, 0x02 | 0x08, Prefs.permissions, 0);
    let seekable = outStream.QueryInterface(Ci.nsISeekableStream);
    if (prealloc && this.parent.totalSize > 0) {
      try {
        seekable.seek(0x00, this.parent.totalSize);
        seekable.setEOF();
        Debug.logString("fileSize set using #2");
      }
      catch (ex) {
        // no-op
      }
    }
    seekable.seek(0x00, this.start + this.written);
    this._outStream = new BufferedOutputStream(outStream, CHUNK_BUFFER_SIZE);
  },
  close: function CH_close() {
    this.running = false;
    if (this._outStream) {
      this._outStream.flush();
      this._outStream.close();
      delete this._outStream;
    }
    this._buffered = 0;
    if (this.parent.is(CANCELED)) {
      this.parent.removeTmpFile();
    }
  },
  rollback: function CH_rollback() {
    if (!this._sessionBytes || this._sessionBytes > this._written) {
      return;
    }
    this._written -= this._sessionBytes;
    this._sessionBytes = 0;
  },
  cancel: function CH_cancel() {
    this.running = false;
    this.close();
    if (this.download) {
      this.download.cancel();
    }
  },
  _written: 0,
  _outStream: null,
  write: function CH_write(aInputStream, aCount) {
    try {
      if (!this._outStream) {
        this.open();
      }
      bytes = this.remainder;
      if (!this.total || aCount < bytes) {
        bytes = aCount;
      }
      if (!bytes) {
        return 0;
      }
      if (bytes < 0) {
        throw new Exception("bytes negative");
      }
      // we're using nsIFileOutputStream
      if (this._outStream.writeFrom(aInputStream, bytes) != bytes) {
        throw ("chunks::write: read/write count mismatch!");
      }
      this._written += bytes;
      this._sessionBytes += bytes;
      this._buffered = Math.min(CHUNK_BUFFER_SIZE, this._buffered + bytes);

      this.parent.timeLastProgress = Utils.getTimestamp();

      return bytes;
    }
    catch (ex) {
      Debug.log('write: ' + this.parent.tmpFile.path, ex);
      throw ex;
    }
    return 0;
  },
  toString: function() {
    let len = this.parent.totalSize ? String(this.parent.totalSize).length  : 10; 
    return Utils.formatNumber(this.start, len)
      + "/"
      + Utils.formatNumber(this.end, len)
      + "/"
      + Utils.formatNumber(this.total, len)
      + " running:"
      + this.running
      + " written/remain:"
      + Utils.formatNumber(this.written, len)
      + "/"
      + Utils.formatNumber(this.remainder, len);
  }
}

var Prompts = {
  _authPrompter: null,
  _prompter: null,
  get authPrompter() {
    if (!this._authPrompter) {
      this._authPrompter = WindowWatcherService.getNewAuthPrompter(window)
        .QueryInterface(Ci.nsIAuthPrompt);    
    }
    return this._authPrompter;
  },
  get prompter() {
    if (!this._prompter) {
      this._prompter = WindowWatcherService.getNewPrompter(window)
        .QueryInterface(Ci.nsIPrompt);
    }
    return this._prompter;
  }
};

function Connection(d, c, getInfo) {

  this.d = d;
  this.c = c;
  this.isInfoGetter = getInfo;
  this.url = d.urlManager.getURL();
  var referrer = d.referrer;
  Debug.logString("starting: " + this.url.url);

  this._chan = IOService.newChannelFromURI(this.url.url.toURL());
  var r = Ci.nsIRequest;
  this._chan.loadFlags = r.LOAD_NORMAL | r.LOAD_BYPASS_CACHE;
  this._chan.notificationCallbacks = this;
  try {
    var encodedChannel = this._chan.QueryInterface(Ci.nsIEncodedChannel);
    encodedChannel.applyConversion = false;
  }
  catch (ex) {
    // no-op
  }
  try {
    let http = this._chan.QueryInterface(Ci.nsIHttpChannel);
    if (c.start + c.written > 0) {
      http.setRequestHeader('Range', 'bytes=' + (c.start + c.written) + "-", false);
    }
    if (this.isInfoGetter && !d.fromMetalink) {
      http.setRequestHeader('Accept', 'application/metalink+xml;q=0.9', true);
    }
    if (referrer instanceof Ci.nsIURI) {
      http.referrer = referrer;
    }
    http.setRequestHeader('Keep-Alive', '', false);
    http.setRequestHeader('Connection', 'close', false);
    if (d.postData) {
      let uc = http.QueryInterface(Ci.nsIUploadChannel);
      uc.setUploadStream(new StringInputStream(d.postData, d.postData.length), null, -1);
      http.requestMethod = 'POST';
    }      
  }
  catch (ex) {
    Debug.log("error setting up channel", ex);
    // no-op
  }
  this.c.running = true;
  this._chan.asyncOpen(this, null);
}

Connection.prototype = {
  _interfaces: [
    Ci.nsISupports,
    Ci.nsISupportsWeakReference,
    Ci.nsIWeakReference,
    Ci.nsICancelable,
    Ci.nsIInterfaceRequestor,
    Ci.nsIStreamListener,
    Ci.nsIRequestObserver,
    Ci.nsIProgressEventSink,
    Ci.nsIChannelEventSink,
    Ci.nsIFTPEventSink,
  ],
  
  cantCount: false,

  QueryInterface: function DL_QI(iid) {
    if (this._interfaces.some(function(i) { return iid.equals(i); })) {
      return this;
    }
    throw Components.results.NS_ERROR_NO_INTERFACE;
  },
  // nsISupportsWeakReference
  GetWeakReference: function DL_GWR() {
    return this;
  },
  // nsIWeakReference
  QueryReferent: function DL_QR(uuid) {
    return this.QueryInterface(uuid);
  },
  // nsICancelable
  cancel: function DL_cancel(aReason) {
    try {
      if (this._closed) {
        return;
      }
      Debug.logString("cancel");
      if (!aReason) {
        aReason = NS_ERROR_BINDING_ABORTED;
      }
      this._chan.cancel(aReason);
      this._closed = true;
    }
    catch (ex) {
      Debug.log("cancel", ex);
    }
  },
  // nsIInterfaceRequestor
  _notImplemented: [
    Ci.nsIDocShellTreeItem, // cookie same-origin checks
    Ci.nsIDOMWindow, // cookie same-origin checks
    Ci.nsIWebProgress, 
  ],
  getInterface: function DL_getInterface(iid) {
    if (this._notImplemented.some(function(i) { return iid.equals(i); })) {
      // we don't want to implement these
      // and we don't want them to pop up in our logs
      throw Components.results.NS_ERROR_NO_INTERFACE;
    }
    if (iid.equals(Ci.nsIAuthPrompt)) {
      return Prompts.authPrompter;
    }
    if (iid.equals(Ci.nsIPrompt)) {
      return Prompts.prompter;
    }
    // for 1.9
    /* this one makes minefield ask for the password again and again :p
    if ('nsIAuthPromptProvider' in Ci && iid.equals(Ci.nsIAuthPromptProvider)) {
      return Prompts.prompter.QueryInterface(Ci.nsIAuthPromptProvider);
    }*/
    // for 1.9
    if ('nsIAuthPrompt2' in Ci && iid.equals(Ci.nsIAuthPrompt2)) {
      return Prompts.authPrompter.QueryInterface(Ci.nsIAuthPrompt2);
    }
    try {
      return this.QueryInterface(iid);
    }
    catch (ex) {
      Debug.log("interface not implemented: " + iid, ex);
      throw ex;
    }
  },

  // nsIChannelEventSink
  onChannelRedirect: function DL_onChannelRedirect(oldChannel, newChannel, flags) {
    if (!this.isInfoGetter) {
      return;
    }
    try {
      this._chan == newChannel;
      this.url.url = newChannel.URI.spec;
      this.d.fileName = this.url.usable.getUsableFileName();
    }
    catch (ex) {
      // no-op
    }
  },
  
  // nsIStreamListener
  onDataAvailable: function DL_onDataAvailable(aRequest, aContext, aInputStream, aOffset, aCount) {
    if (this._closed) {
      throw 0x804b0002; // NS_BINDING_ABORTED;
    }
    try {
      // we want to kill ftp chans as well which do not seem to respond to cancel correctly.
      if (!this.c.write(aInputStream, aCount)) {
        // we already got what we wanted
        this.cancel();
      }
    }
    catch (ex) {
      Debug.log('onDataAvailable', ex);
      this.d.fail(_("accesserror"), _("permissions") + " " + _("destpath") + ". " + _("checkperm"), _("accesserror"));
    }
  },
  
  // nsIFTPEventSink
  OnFTPControlLog: function(server, msg) {},
  
  handleError: function DL_handleError() {
    let c = this.c;
    let d = this.d;
    
    c.cancel();
    d.dumpScoreboard();
    if (d.chunks.indexOf(c) == -1) {
      // already killed;
      return true;
    }

    Debug.logString("handleError: problem found; trying to recover");
    
    if (d.urlManager.markBad(this.url)) {
      Debug.logString("handleError: fresh urls available, kill this one and use another!");
      d.timeLastProgress = Utils.getTimestamp();
      return true;
    }
    
    Debug.logString("affected: " + c);
    
    let max = -1, found = -1;
    for each (let cmp in d.chunks) {
      if (cmp.start < c.start && cmp.start > max) {
        found = i;
        max = cmp.start;
      }
    }
    if (found > -1) {
      Debug.logString("handleError: found joinable chunk; recovering suceeded, chunk: " + found);
      d.chunks[found].end = c.end;
      if (--d.maxChunks == 1) {
        //d.resumable = false;
      }
      d.chunks = d.chunks.filter(function(ch) { return ch != c; });
      d.chunks.sort(function(a,b) { return a.start - b.start; });
      
      // check for overlapping ranges we might have created
      // otherwise we'll receive a size mismatch
      // this means that we're gonna redownload an already finished chunk...
      for (let i = d.chunks.length - 2; i > -1; --i) {
        let c1 = d.chunks[i], c2 = d.chunks[i + 1];
        if (c1.end >= c2.end) {
          if (c2.running) {
            // should never ever happen :p
            d.dumpScoreboard();
            Debug.logString("overlapping:\n" + c1 + "\n" + c2);
            d.fail("Internal error", "Please notify the developers that there were 'overlapping chunks'!", "Internal error (please report)");
            return false;
          }
          d.chunks.splice(i + 1, 1);
        }
      }
      let ac = 0;
      d.chunks.forEach(function(c) { if (c.running) { ++ac; }});
      d.activeChunks = ac;
      c.close();
      
      d.save();
      d.dumpScoreboard();
      return true;
    }
    return false;
  },
  handleHttp: function DL_handleHttp(aChannel) {
    let c = this.c;
    let d = this.d;
    
    let code = 0, status = 'Server returned nothing';
    try {
      code = aChannel.responseStatus;
      status = aChannel.responseStatusText;
    }
    catch (ex) {
      return true;
    }
     
    if (code >= 400) {
      if (!this.handleError()) {
        Debug.log("handleError: Cannot recover from problem!", code);
        if ([401, 402, 407, 500, 502, 503, 504].indexOf(code) != -1) {
          Debug.log("we got temp failure!", code);
          d.pause();
          d.markAutoRetry();
          d.status = code >= 500 ? _('temperror') : _('autherror');
        }
        else if (code == 450) {
          d.fail(
            _('pcerrortitle'),
            _('pcerrortext'),
            _('pcerrortitle')
          );
        }
        else {
          var file = d.fileName.length > 50 ? d.fileName.substring(0, 50) + "..." : d.fileName;
          code = Utils.formatNumber(code, 3);
          d.fail(
            _("error", [code]),
            _("failed", [file]) + " " + _("sra", [code]) + ": " + status,
            _("error", [code])
          );
        }
        // any data that we got over this channel should be considered "corrupt"
        c.rollback();
        d.save();
      }
      return false;
    }

    // not partial content altough we are multi-chunk
    if (code != 206 && !this.isInfoGetter) {
      Debug.log(d + ": Server returned a " + aChannel.responseStatus + " response instead of 206", this.isInfoGetter);
      
      d.resumable = false;

      if (!this.handleError()) {
        vis = {value: '', visitHeader: function(a,b) { this.value += a + ': ' + b + "\n"; }};
        aChannel.visitRequestHeaders(vis);
        Debug.logString("Request Headers\n\n" + vis.value);
        vis.value = '';
        aChannel.visitResponseHeaders(vis);
        Debug.logString("Response Headers\n\n" + vis.value);
        d.cancel();
        d.resumable = false;
        d.safeRetry();
        return false;
      }
    }

    var visitor = null;
    try {
      visitor = d.visitors.visit(aChannel);
    }
    catch (ex) {
      Debug.log("header failed! " + d, ex);
      // restart download from the beginning
      d.cancel();
      d.resumable = false;
      d.safeRetry();
      return false;
    }
    
    if (!this.isInfoGetter) {
      return false;
    }

    if (visitor.type) {
      d.contentType = visitor.type;
    }

    // compression?
    if (['gzip', 'deflate'].indexOf(visitor.encoding) != -1 && !d.contentType.match(/gzip/i) && !d.fileName.match(/\.gz$/i)) {
      d.compression = visitor.encoding;
    }
    else {
      d.compression = null;
    }

    // accept range
    d.resumable &= visitor.acceptRanges;

    if (visitor.type && visitor.type.search(/application\/metalink\+xml/) != -1) {
      d.isMetalink = true;
      d.resumable = false;
    }

    if (visitor.contentlength > 0) {
      d.totalSize = visitor.contentlength;
    } else {
      d.totalSize = 0;
    }
    
    if (visitor.fileName && visitor.fileName.length > 0) {
      // if content disposition hasn't an extension we use extension of URL
      let newName = visitor.fileName;
      let ext = this.url.usable.getExtension();
      if (visitor.fileName.lastIndexOf('.') == -1 && ext) {
        newName += '.' + ext;
      }
      d.fileName = newName.getUsableFileName();
    }

    return false;
  },
  
  // Generic handler for now :p
  handleFtp: function  DL_handleFtp(aChannel) {
    return this.handleGeneric(aChannel);
  },
  
  handleGeneric: function DL_handleGeneric(aChannel) {
    var c = this.c;
    var d = this.d;
    
    // hack: determine if we are a multi-part chunk,
    // if so something bad happened, 'cause we aren't supposed to be multi-part
    if (c.start != 0 && d.is(RUNNING)) {
      if (!this.handleError()) {
        Debug.log(d + ": Server error or disconnection", "(type 1)");
        d.status = _("servererror");
        d.markAutoRetry();
        d.pause();
      }
      return false;
    }     
      
    // try to get the size anyway ;)
    try {
      let pb = aChannel.QueryInterface(Ci.nsIPropertyBag2);
      d.totalSize = Math.max(pb.getPropertyAsInt64('content-length'), 0);
    }
    catch (ex) {
      try {
        d.totalSize = Math.max(aChannel.contentLength, 0);
      }
      catch (ex) {
        d.totalSize = 0;
      }
    }
    d.resumable = false;
    return false;
  },
  
  //nsIRequestObserver,
  _supportedChannels: [
    {i:Ci.nsIHttpChannel, f:'handleHttp'},
    {i:Ci.nsIFTPChannel, f:'handleFtp'},
    {i:Ci.nsIChannel, f:'handleGeneric'}
  ],
  onStartRequest: function DL_onStartRequest(aRequest, aContext) {
    let c = this.c;
    let d = this.d;
    Debug.logString('StartRequest: ' + c);
  
    this.started = true;
    try {
      for each (let sc in this._supportedChannels) {
        let chan = null;
        try {
          chan = aRequest.QueryInterface(sc.i);
        }
        catch (ex) {
          continue;
        }
        if (chan) {
          if ((this.rexamine = this[sc.f](chan))) {
             return;
          }
          break;
        }         
      }

      if (this.isInfoGetter) {
        // Checks for available disk space.
        
        if (d.fileName.getExtension() == 'metalink') {
          d.isMetalink = true;
          d.resumable = true;
        }       
        
        var tsd = d.totalSize;
        try {
          if (tsd) {
            let tmp = Prefs.tempLocation, vtmp = 0;
            if (tmp) {
              vtmp = Utils.validateDir(tmp);
              if (!vtmp && Utils.getFreeDisk(vtmp) < tsd) {
                d.fail(_("ndsa"), _("spacetemp"), _("freespace"));
                return;
              }
            }
            let realDest = Utils.validateDir(d.destinationPath);
            if (!realDest) {
              throw new Error("invalid destination folder");
            }
            var nsd = Utils.getFreeDisk(realDest);
            // Same save path or same disk (we assume that tmp.avail == dst.avail means same disk)
            // simply moving should succeed
            if (d.compression && (!tmp || Utils.getFreeDisk(vtmp) == nsd)) {
              // we cannot know how much space we will consume after decompressing.
              // so we assume factor 1.0 for the compressed and factor 1.5 for the decompressed file.
              tsd *= 2.5;
            }
            if (nsd < tsd) {
              Debug.logString("nsd: " +  nsd + ", tsd: " + tsd);
              d.fail(_("ndsa"), _("spacedir"), _("freespace"));
              return;
            }
          }
        }
        catch (ex) {
          Debug.log("size check threw", ex);
          d.fail(_("accesserror"), _("permissions") + " " + _("destpath") + ". " + _("checkperm"), _("accesserror"));
          return;
        }
        
        if (!d.totalSize) {
          d.resumable = false;          
          this.cantCount = true;
        }
        if (!d.resumable) {
          d.maxChunks = 1;
        }
        c.end = d.totalSize - 1;
        delete this.isInfoGetter;
        
        // Explicitly trigger rebuildDestination here, as we might have received
        // a html content type and need to rewrite the file
        d.rebuildDestination();
        ConflictManager.resolve(d);
      }
      
      if (d.resumable && !d.is(CANCELED)) {
        d.resumeDownload();
      }
    }
    catch (ex) {
      Debug.log("onStartRequest", ex);
    }
  },
  onStopRequest: function DL_onStopRequest(aRequest, aContext, aStatusCode) {
    try {
      Debug.logString('StopRequest');
    }
    catch (ex) {
      return;
    }
    
    // shortcuts
    let c = this.c;
    let d = this.d;
    c.close();
    
    if (d.chunks.indexOf(c) == -1) {
      return;
    }

    // update flags and counters
    d.refreshPartialSize();
    --d.activeChunks;

    // check if we're complete now
    if (d.is(RUNNING) && d.chunks.every(function(e) { return e.complete; })) {
      if (!d.resumeDownload()) {
        d.state = FINISHING;
        Debug.logString(d + ": Download is complete!");
        d.finishDownload();
        return;
      }
    }

    if (c.starter && -1 != [
      NS_ERROR_CONNECTION_REFUSED,
      NS_ERROR_UNKNOWN_HOST,
      NS_ERROR_NET_TIMEOUT,
      NS_ERROR_NET_RESET
    ].indexOf(aStatusCode)) {
      Debug.log(d + ": Server error or disconnection", "(type 3)");
      d.pause();
      d.status = _("servererror");
      d.markAutoRetry();        
      return;
    }   

    // routine for normal chunk
    Debug.logString(d + ": Chunk " + c.start + "-" + c.end + " finished.");
    
    // rude way to determine disconnection: if connection is closed before download is started we assume a server error/disconnection
    if (c.starter && d.is(RUNNING)) {
      if (!d.urlManager.markBad(this.url)) {
        Debug.log(d + ": Server error or disconnection", "(type 2)");
        d.pause();
        d.status = _("servererror");
        d.markAutoRetry();        
      }
      else {
        Debug.log("caught bad server", d.toString());
        d.cancel();
        d.safeRetry();
      }
      return;     
    }

    if (!d.is(PAUSED, CANCELED, FINISHING) && d.chunks.length == 1 && d.chunks[0] == c) {
      if (d.resumable) {
        d.pause();
        d.markAutoRetry();
        d.status = _('errmismatchtitle');
      }
      else {
        d.fail(
          _('errmismatchtitle'),
          _('errmismatchtext', [d.partialSize, d.totalSize]),
          _('errmismatchtitle')
        );
      }
      return;     
    }
    if (!d.is(PAUSED, CANCELED)) {
      d.resumeDownload();
    }
  },

  // nsIProgressEventSink
  onProgress: function DL_onProgress(aRequest, aContext, aProgress, aProgressMax) {
    try {
      // shortcuts
      let c = this.c;
      let d = this.d;
      
      if (this.reexamine) {
        Debug.logString(d + ": reexamine");
        this.onStartRequest(aRequest, aContext);
        if (this.reexamine) {
          return;
        }
      }

      // update download tree row
      if (d.is(RUNNING)) {
        d.refreshPartialSize();

        if (!this.resumable && d.totalSize) {
          // basic integrity check
          if (d.partialSize > d.totalSize) {
            d.dumpScoreboard();
            Debug.logString(d + ": partialSize > totalSize" + "(" + d.partialSize + "/" + d.totalSize + "/" + ( d.partialSize - d.totalSize) + ")");
            d.fail(
              _('errmismatchtitle'),
              _('errmismatchtext', [d.partialSize, d.totalSize]),
              _('errmismatchtitle')
            );
            return;
          }
        }
        else {
          d.status = _("downloading");
        }
      }
    }
    catch(ex) {
      Debug.log("onProgressChange():", e);
    }
  },
  onStatus: function  DL_onStatus(aRequest, aContext, aStatus, aStatusArg) {}
};

function startDownloads(start, downloads) {

  var numbefore = Tree.rowCount - 1;
  const DESCS = ['description', 'ultDescription'];
  
  let g = downloads;
  if ('length' in downloads) {
    g = function() {
       for each (let i in downloads) {
        yield i;
       }
    }();
  }

  let added = 0;
  let removeableTabs = {};
  Tree.beginUpdate();
  SessionManager.beginUpdate();
  for (let e in g) {

    var desc = "";
    DESCS.some(
      function(i) {
        if (typeof(e[i]) == 'string' && e[i].length) {
          desc = e.description;
          return true;
        }
        return false;
      }
    );
    
    let qi = new QueueItem();
    let lnk = e.url;
    if (typeof lnk == 'string') {
      qi.urlManager = new UrlManager([new DTA_URL(lnk)]);
    }
    else if (lnk instanceof UrlManager) {
      qi.urlManager = lnk;
    }
    else {
      qi.urlManager = new UrlManager([lnk]);
    }
    qi.numIstance = e.numIstance;
  
    if (e.referrer) {
      try {
        qi.referrer = e.referrer.toURL();
      }
      catch (ex) {
        // We might have been fed with about:blank or other crap. so ignore.
      }
    }
    // only access the setter of the last so that we don't generate stuff trice.
    qi._pathName = e.dirSave.addFinalSlash().toString();
    qi._description = desc ? desc : '';
    qi._mask = e.mask;
    qi.fromMetalink = !!e.fromMetalink;
    if (e.fileName) {
      qi.fileName = e.fileName;
    }
    else {
      qi.fileName = qi.urlManager.usable.getUsableFileName();
    }
    if (e.startDate) {
      qi.startDate = e.startDate;
    }
    if (e.url.hash) {
      qi.hash = e.url.hash;
    }
    else if (e.hash) {
      qi.hash = e.hash;
    }
    else {
      qi.hash = null; // to initialize prettyHash 
    }

    let postData = ContentHandling.getPostDataFor(qi.urlManager.url.toURI());
    if (e.url.postData) {
      postData = e.url.postData;
    }
    if (postData) {
      qi.postData = postData;
    }   

    qi.state = start ? QUEUED : PAUSED;
    if (qi.is(QUEUED)) {
      qi.status = _('inqueue');
    }
    else {
      qi.status = _('paused');
    }
    qi.save();    
    Tree.add(qi);
    ++added;
  }
  SessionManager.endUpdate();
  Tree.endUpdate();

  var boxobject = Tree._box;
  boxobject.QueryInterface(Ci.nsITreeBoxObject);
  if (added <= boxobject.getPageLength()) {
    boxobject.scrollToRow(Tree.rowCount - boxobject.getPageLength());
  }
  else {
    boxobject.scrollToRow(numbefore);
  }
}
const FileOutputStream = Components.Constructor(
  '@mozilla.org/network/file-output-stream;1',
  'nsIFileOutputStream',
  'init'
);

var ConflictManager = {
  _items: [],
  resolve: function CM_resolve(download, reentry) {
    if (!this._check(download)) {
      if (reentry) {
        download[reentry]();
      }
      return;
    }
    for each (let item in this._items.length) {
      if (item.download == download) {
        Debug.logString("conflict resolution updated to: " + reentry);
        item.reentry = reentry;
        return;
      }
    }
    Debug.logString("conflict resolution queued to: " + reentry);
    this._items.push({download: download, reentry: reentry});
    this._process();
  },
  _check: function CM__check(download) {
    let dest = new FileFactory(download.destinationFile);
    let sn = false;
    if (download.is(RUNNING)) {
      sn = Dialog.checkSameName(download, download.destinationFile);
    }
    Debug.logString("conflict check: " + sn + "/" + dest.exists() + " for " + download.destinationFile);
    return dest.exists() || sn;
  },
  _process: function CM__process() {
    if (this._processing) {
      return;
    }
    let cur;
    while (this._items.length) {
      cur = this._items[0];
      if (!this._check(cur.download)) {
        if (reentry) {
          cur.download[reentry]();
        }
        this._items.shift();
        continue;
      }
      break;
    }
    if (!this._items.length) {
      return;
    }
  
    if (Prefs.conflictResolution != 3) {
      this._return(Prefs.conflictResolution);
      return;
    }
    if ('_sessionSetting' in this) {
      this._return(this._sessionSetting);
      return;
    }
    if (cur.download.shouldOverwrite) {
      this._return(1);
      return;
    }
    
    this._computeConflicts(cur);

    var options = {
      url: cur.download.urlManager.usable.cropCenter(45),
      fn: cur.download.destinationName.cropCenter(45),
      newDest: cur.newDest.cropCenter(45)
    };
    
    this._processing = true;
    
    window.openDialog(
      "chrome://dta/content/dta/manager/conflicts.xul",
      "_blank",
      "chrome,centerscreen,resizable=no,dialog,close=no,dependent",
      options, this
    );
  },
  _computeConflicts: function CM__computeConflicts(cur) {
    let download = cur.download;
    download.conflicts = 0;
    let basename = download.destinationName;
    let newDest = new FileFactory(download.destinationFile);
    let i = 1;
    for (;; ++i) {
      newDest.leafName = Utils.formatConflictName(basename, i);
      if (!newDest.exists() && (!download.is(RUNNING) || !Dialog.checkSameName(this, newDest.path))) {
        break;
      }
    }
    cur.newDest = newDest.leafName;
    cur.conflicts = i;  
  },
  _returnFromDialog: function CM__returnFromDialog(option, type) {
    if (type == 1) {
      this._sessionSetting = option;
    }
    if (type == 2) {
      Preferences.setDTA('conflictresolution', option);
    }   
    this._return(option);
  },
  _return: function CM__return(option) {
    let cur = this._items[0];
    switch (option) {
      /* rename */    case 0: this._computeConflicts(cur); cur.download.conflicts = cur.conflicts; break;
      /* overwrite */ case 1: cur.download.shouldOverwrite = true; break;
      /* skip */      default: cur.download.cancel(_('skipped')); break;
    }
    if (cur.reentry) {
      cur.download[cur.reentry]();
    }
    this._items.shift();
    this._processing = false;
    this._process();
  }
};

var Serializer = {
  encode: function(obj) {
    if ('nsIJSON' in Ci) {
      Debug.logString("hello json");
      let json = Serv('@mozilla.org/dom/json;1', 'nsIJSON');
      this.encode = function(obj) {
        return json.encode(obj);
      }
    }
    else {
      this.encode = function(obj) {
        return obj.toSource();
      }
    }
    return this.encode(obj);
  },
  decode: function(str) {
    if ('nsIJSON' in Ci) {
      Debug.logString("hello json");
      let json = Serv('@mozilla.org/dom/json;1', 'nsIJSON');
      this.decode = function(str) {
        try {
          return json.decode(str);
        }
        catch (ex) {
          return eval(str);
        }
      }
    }
    else {
      this.decode = function(str) {
        return eval(str);
      }
    }
    return this.decode(str);
  }
};