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httpd.js (154638B)

---

 /* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */
 /* vim:set ts=2 sw=2 sts=2 et: */
 /* 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/. */
 
 /*
  * An implementation of an HTTP server both as a loadable script and as an XPCOM
  * component.  See the accompanying README file for user documentation on
  * httpd.js.
  */
 
 this.EXPORTED_SYMBOLS = [
   "HTTP_400",
   "HTTP_401",
   "HTTP_402",
   "HTTP_403",
   "HTTP_404",
   "HTTP_405",
   "HTTP_406",
   "HTTP_407",
   "HTTP_408",
   "HTTP_409",
   "HTTP_410",
   "HTTP_411",
   "HTTP_412",
   "HTTP_413",
   "HTTP_414",
   "HTTP_415",
   "HTTP_417",
   "HTTP_500",
   "HTTP_501",
   "HTTP_502",
   "HTTP_503",
   "HTTP_504",
   "HTTP_505",
   "HttpError",
   "HttpServer",
 ];
 
 Components.utils.import("resource://gre/modules/XPCOMUtils.jsm");
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cr = Components.results;
 const Cu = Components.utils;
 const CC = Components.Constructor;
 
 const PR_UINT32_MAX = Math.pow(2, 32) - 1;
 
 /** True if debugging output is enabled, false otherwise. */
 var DEBUG = false; // non-const *only* so tweakable in server tests
 
 /** True if debugging output should be timestamped. */
 var DEBUG_TIMESTAMP = false; // non-const so tweakable in server tests
 
 var gGlobalObject = this;
 
 /**
  * Asserts that the given condition holds.  If it doesn't, the given message is
  * dumped, a stack trace is printed, and an exception is thrown to attempt to
  * stop execution (which unfortunately must rely upon the exception not being
  * accidentally swallowed by the code that uses it).
  */
 function NS_ASSERT(cond, msg)
 {
   if (DEBUG && !cond)
   {
     dumpn("###!!!");
     dumpn("###!!! ASSERTION" + (msg ? ": " + msg : "!"));
     dumpn("###!!! Stack follows:");
 
     var stack = new Error().stack.split(/\n/);
     dumpn(stack.map(function(val) { return "###!!!   " + val; }).join("\n"));
 
     throw Cr.NS_ERROR_ABORT;
   }
 }
 
 /** Constructs an HTTP error object. */
 this.HttpError = function HttpError(code, description)
 {
   this.code = code;
   this.description = description;
 }
 HttpError.prototype =
 {
   toString: function()
   {
     return this.code + " " + this.description;
   }
 };
 
 /**
  * Errors thrown to trigger specific HTTP server responses.
  */
 this.HTTP_400 = new HttpError(400, "Bad Request");
 this.HTTP_401 = new HttpError(401, "Unauthorized");
 this.HTTP_402 = new HttpError(402, "Payment Required");
 this.HTTP_403 = new HttpError(403, "Forbidden");
 this.HTTP_404 = new HttpError(404, "Not Found");
 this.HTTP_405 = new HttpError(405, "Method Not Allowed");
 this.HTTP_406 = new HttpError(406, "Not Acceptable");
 this.HTTP_407 = new HttpError(407, "Proxy Authentication Required");
 this.HTTP_408 = new HttpError(408, "Request Timeout");
 this.HTTP_409 = new HttpError(409, "Conflict");
 this.HTTP_410 = new HttpError(410, "Gone");
 this.HTTP_411 = new HttpError(411, "Length Required");
 this.HTTP_412 = new HttpError(412, "Precondition Failed");
 this.HTTP_413 = new HttpError(413, "Request Entity Too Large");
 this.HTTP_414 = new HttpError(414, "Request-URI Too Long");
 this.HTTP_415 = new HttpError(415, "Unsupported Media Type");
 this.HTTP_417 = new HttpError(417, "Expectation Failed");
 
 this.HTTP_500 = new HttpError(500, "Internal Server Error");
 this.HTTP_501 = new HttpError(501, "Not Implemented");
 this.HTTP_502 = new HttpError(502, "Bad Gateway");
 this.HTTP_503 = new HttpError(503, "Service Unavailable");
 this.HTTP_504 = new HttpError(504, "Gateway Timeout");
 this.HTTP_505 = new HttpError(505, "HTTP Version Not Supported");
 
 /** Creates a hash with fields corresponding to the values in arr. */
 function array2obj(arr)
 {
   var obj = {};
   for (var i = 0; i < arr.length; i++)
     obj[arr[i]] = arr[i];
   return obj;
 }
 
 /** Returns an array of the integers x through y, inclusive. */
 function range(x, y)
 {
   var arr = [];
   for (var i = x; i <= y; i++)
     arr.push(i);
   return arr;
 }
 
 /** An object (hash) whose fields are the numbers of all HTTP error codes. */
 const HTTP_ERROR_CODES = array2obj(range(400, 417).concat(range(500, 505)));
 
 
 /**
  * The character used to distinguish hidden files from non-hidden files, a la
  * the leading dot in Apache.  Since that mechanism also hides files from
  * easy display in LXR, ls output, etc. however, we choose instead to use a
  * suffix character.  If a requested file ends with it, we append another
  * when getting the file on the server.  If it doesn't, we just look up that
  * file.  Therefore, any file whose name ends with exactly one of the character
  * is "hidden" and available for use by the server.
  */
 const HIDDEN_CHAR = "^";
 
 /**
  * The file name suffix indicating the file containing overridden headers for
  * a requested file.
  */
 const HEADERS_SUFFIX = HIDDEN_CHAR + "headers" + HIDDEN_CHAR;
 
 /** Type used to denote SJS scripts for CGI-like functionality. */
 const SJS_TYPE = "sjs";
 
 /** Base for relative timestamps produced by dumpn(). */
 var firstStamp = 0;
 
 /** dump(str) with a trailing "\n" -- only outputs if DEBUG. */
 function dumpn(str)
 {
   if (DEBUG)
   {
     var prefix = "HTTPD-INFO | ";
     if (DEBUG_TIMESTAMP)
     {
       if (firstStamp === 0)
         firstStamp = Date.now();
 
       var elapsed = Date.now() - firstStamp; // milliseconds
       var min = Math.floor(elapsed / 60000);
       var sec = (elapsed % 60000) / 1000;
 
       if (sec < 10)
         prefix += min + ":0" + sec.toFixed(3) + " | ";
       else
         prefix += min + ":" + sec.toFixed(3) + " | ";
     }
 
     dump(prefix + str + "\n");
   }
 }
 
 /** Dumps the current JS stack if DEBUG. */
 function dumpStack()
 {
   // peel off the frames for dumpStack() and Error()
   var stack = new Error().stack.split(/\n/).slice(2);
   stack.forEach(dumpn);
 }
 
 
 /** The XPCOM thread manager. */
 var gThreadManager = null;
 
 /** The XPCOM prefs service. */
 var gRootPrefBranch = null;
 function getRootPrefBranch()
 {
   if (!gRootPrefBranch)
   {
     gRootPrefBranch = Cc["@mozilla.org/preferences-service;1"]
                         .getService(Ci.nsIPrefBranch);
   }
   return gRootPrefBranch;
 }
 
 /**
  * JavaScript constructors for commonly-used classes; precreating these is a
  * speedup over doing the same from base principles.  See the docs at
  * http://developer.mozilla.org/en/docs/Components.Constructor for details.
  */
 const ServerSocket = CC("@mozilla.org/network/server-socket;1",
                         "nsIServerSocket",
                         "init");
 const ScriptableInputStream = CC("@mozilla.org/scriptableinputstream;1",
                                  "nsIScriptableInputStream",
                                  "init");
 const Pipe = CC("@mozilla.org/pipe;1",
                 "nsIPipe",
                 "init");
 const FileInputStream = CC("@mozilla.org/network/file-input-stream;1",
                            "nsIFileInputStream",
                            "init");
 const ConverterInputStream = CC("@mozilla.org/intl/converter-input-stream;1",
                                 "nsIConverterInputStream",
                                 "init");
 const WritablePropertyBag = CC("@mozilla.org/hash-property-bag;1",
                                "nsIWritablePropertyBag2");
 const SupportsString = CC("@mozilla.org/supports-string;1",
                           "nsISupportsString");
 
 /* These two are non-const only so a test can overwrite them. */
 var BinaryInputStream = CC("@mozilla.org/binaryinputstream;1",
                            "nsIBinaryInputStream",
                            "setInputStream");
 var BinaryOutputStream = CC("@mozilla.org/binaryoutputstream;1",
                             "nsIBinaryOutputStream",
                             "setOutputStream");
 
 /**
  * Returns the RFC 822/1123 representation of a date.
  *
  * @param date : Number
  *   the date, in milliseconds from midnight (00:00:00), January 1, 1970 GMT
  * @returns string
  *   the representation of the given date
  */
 function toDateString(date)
 {
   //
   // rfc1123-date = wkday "," SP date1 SP time SP "GMT"
   // date1        = 2DIGIT SP month SP 4DIGIT
   //                ; day month year (e.g., 02 Jun 1982)
   // time         = 2DIGIT ":" 2DIGIT ":" 2DIGIT
   //                ; 00:00:00 - 23:59:59
   // wkday        = "Mon" | "Tue" | "Wed"
   //              | "Thu" | "Fri" | "Sat" | "Sun"
   // month        = "Jan" | "Feb" | "Mar" | "Apr"
   //              | "May" | "Jun" | "Jul" | "Aug"
   //              | "Sep" | "Oct" | "Nov" | "Dec"
   //
 
   const wkdayStrings = ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"];
   const monthStrings = ["Jan", "Feb", "Mar", "Apr", "May", "Jun",
                         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];
 
   /**
    * Processes a date and returns the encoded UTC time as a string according to
    * the format specified in RFC 2616.
    *
    * @param date : Date
    *   the date to process
    * @returns string
    *   a string of the form "HH:MM:SS", ranging from "00:00:00" to "23:59:59"
    */
   function toTime(date)
   {
     var hrs = date.getUTCHours();
     var rv  = (hrs < 10) ? "0" + hrs : hrs;
     
     var mins = date.getUTCMinutes();
     rv += ":";
     rv += (mins < 10) ? "0" + mins : mins;
 
     var secs = date.getUTCSeconds();
     rv += ":";
     rv += (secs < 10) ? "0" + secs : secs;
 
     return rv;
   }
 
   /**
    * Processes a date and returns the encoded UTC date as a string according to
    * the date1 format specified in RFC 2616.
    *
    * @param date : Date
    *   the date to process
    * @returns string
    *   a string of the form "HH:MM:SS", ranging from "00:00:00" to "23:59:59"
    */
   function toDate1(date)
   {
     var day = date.getUTCDate();
     var month = date.getUTCMonth();
     var year = date.getUTCFullYear();
 
     var rv = (day < 10) ? "0" + day : day;
     rv += " " + monthStrings[month];
     rv += " " + year;
 
     return rv;
   }
 
   date = new Date(date);
 
   const fmtString = "%wkday%, %date1% %time% GMT";
   var rv = fmtString.replace("%wkday%", wkdayStrings[date.getUTCDay()]);
   rv = rv.replace("%time%", toTime(date));
   return rv.replace("%date1%", toDate1(date));
 }
 
 /**
  * Prints out a human-readable representation of the object o and its fields,
  * omitting those whose names begin with "_" if showMembers != true (to ignore
  * "private" properties exposed via getters/setters).
  */
 function printObj(o, showMembers)
 {
   var s = "******************************\n";
   s +=    "o = {\n";
   for (var i in o)
   {
     if (typeof(i) != "string" ||
         (showMembers || (i.length > 0 && i[0] != "_")))
       s+= "      " + i + ": " + o[i] + ",\n";
   }
   s +=    "    };\n";
   s +=    "******************************";
   dumpn(s);
 }
 
 /**
  * Instantiates a new HTTP server.
  */
 function nsHttpServer()
 {
   if (!gThreadManager)
     gThreadManager = Cc["@mozilla.org/thread-manager;1"].getService();
 
   /** The port on which this server listens. */
   this._port = undefined;
 
   /** The socket associated with this. */
   this._socket = null;
 
   /** The handler used to process requests to this server. */
   this._handler = new ServerHandler(this);
 
   /** Naming information for this server. */
   this._identity = new ServerIdentity();
 
   /**
    * Indicates when the server is to be shut down at the end of the request.
    */
   this._doQuit = false;
 
   /**
    * True if the socket in this is closed (and closure notifications have been
    * sent and processed if the socket was ever opened), false otherwise.
    */
   this._socketClosed = true;
 
   /**
    * Used for tracking existing connections and ensuring that all connections
    * are properly cleaned up before server shutdown; increases by 1 for every
    * new incoming connection.
    */
   this._connectionGen = 0;
 
   /**
    * Hash of all open connections, indexed by connection number at time of
    * creation.
    */
   this._connections = {};
 }
 nsHttpServer.prototype =
 {
   classID: Components.ID("{54ef6f81-30af-4b1d-ac55-8ba811293e41}"),
 
   // NSISERVERSOCKETLISTENER
 
   /**
    * Processes an incoming request coming in on the given socket and contained
    * in the given transport.
    *
    * @param socket : nsIServerSocket
    *   the socket through which the request was served
    * @param trans : nsISocketTransport
    *   the transport for the request/response
    * @see nsIServerSocketListener.onSocketAccepted
    */
   onSocketAccepted: function(socket, trans)
   {
     dumpn("*** onSocketAccepted(socket=" + socket + ", trans=" + trans + ")");
 
     dumpn(">>> new connection on " + trans.host + ":" + trans.port);
 
     const SEGMENT_SIZE = 8192;
     const SEGMENT_COUNT = 1024;
     try
     {
       var input = trans.openInputStream(0, SEGMENT_SIZE, SEGMENT_COUNT)
                        .QueryInterface(Ci.nsIAsyncInputStream);
       var output = trans.openOutputStream(0, 0, 0);
     }
     catch (e)
     {
       dumpn("*** error opening transport streams: " + e);
       trans.close(Cr.NS_BINDING_ABORTED);
       return;
     }
 
     var connectionNumber = ++this._connectionGen;
 
     try
     {
       var conn = new Connection(input, output, this, socket.port, trans.port,
                                 connectionNumber);
       var reader = new RequestReader(conn);
 
       // XXX add request timeout functionality here!
 
       // Note: must use main thread here, or we might get a GC that will cause
       //       threadsafety assertions.  We really need to fix XPConnect so that
       //       you can actually do things in multi-threaded JS.  :-(
       input.asyncWait(reader, 0, 0, gThreadManager.mainThread);
     }
     catch (e)
     {
       // Assume this connection can't be salvaged and bail on it completely;
       // don't attempt to close it so that we can assert that any connection
       // being closed is in this._connections.
       dumpn("*** error in initial request-processing stages: " + e);
       trans.close(Cr.NS_BINDING_ABORTED);
       return;
     }
 
     this._connections[connectionNumber] = conn;
     dumpn("*** starting connection " + connectionNumber);
   },
 
   /**
    * Called when the socket associated with this is closed.
    *
    * @param socket : nsIServerSocket
    *   the socket being closed
    * @param status : nsresult
    *   the reason the socket stopped listening (NS_BINDING_ABORTED if the server
    *   was stopped using nsIHttpServer.stop)
    * @see nsIServerSocketListener.onStopListening
    */
   onStopListening: function(socket, status)
   {
     dumpn(">>> shutting down server on port " + socket.port);
     for (var n in this._connections) {
       if (!this._connections[n]._requestStarted) {
         this._connections[n].close();
       }
     }
     this._socketClosed = true;
     if (this._hasOpenConnections()) {
       dumpn("*** open connections!!!");
     }
     if (!this._hasOpenConnections())
     {
       dumpn("*** no open connections, notifying async from onStopListening");
 
       // Notify asynchronously so that any pending teardown in stop() has a
       // chance to run first.
       var self = this;
       var stopEvent =
         {
           run: function()
           {
             dumpn("*** _notifyStopped async callback");
             self._notifyStopped();
           }
         };
       gThreadManager.currentThread
                     .dispatch(stopEvent, Ci.nsIThread.DISPATCH_NORMAL);
     }
   },
 
   // NSIHTTPSERVER
 
   //
   // see nsIHttpServer.start
   //
   start: function(port)
   {
     this._start(port, "localhost")
   },
 
   _start: function(port, host)
   {
     if (this._socket)
       throw Cr.NS_ERROR_ALREADY_INITIALIZED;
 
     this._port = port;
     this._doQuit = this._socketClosed = false;
 
     this._host = host;
 
     // The listen queue needs to be long enough to handle
     // network.http.max-persistent-connections-per-server or
     // network.http.max-persistent-connections-per-proxy concurrent
     // connections, plus a safety margin in case some other process is
     // talking to the server as well.
     var prefs = getRootPrefBranch();
     var maxConnections = 5 + Math.max(
       prefs.getIntPref("network.http.max-persistent-connections-per-server"),
       prefs.getIntPref("network.http.max-persistent-connections-per-proxy"));
 
     try
     {
       var loopback = true;
       if (this._host != "127.0.0.1" && this._host != "localhost") {
         var loopback = false;
       }
 
       // When automatically selecting a port, sometimes the chosen port is
       // "blocked" from clients. We don't want to use these ports because
       // tests will intermittently fail. So, we simply keep trying to to
       // get a server socket until a valid port is obtained. We limit
       // ourselves to finite attempts just so we don't loop forever.
       var ios = Cc["@mozilla.org/network/io-service;1"]
                   .getService(Ci.nsIIOService);
       var socket;
       for (var i = 100; i; i--)
       {
         var temp = new ServerSocket(this._port,
                                     loopback, // true = localhost, false = everybody
                                     maxConnections);
 
         var allowed = ios.allowPort(temp.port, "http");
         if (!allowed)
         {
           dumpn(">>>Warning: obtained ServerSocket listens on a blocked " +
                 "port: " + temp.port);
         }
 
         if (!allowed && this._port == -1)
         {
           dumpn(">>>Throwing away ServerSocket with bad port.");
           temp.close();
           continue;
         }
 
         socket = temp;
         break;
       }
 
       if (!socket) {
         throw new Error("No socket server available. Are there no available ports?");
       }
 
       dumpn(">>> listening on port " + socket.port + ", " + maxConnections +
             " pending connections");
       socket.asyncListen(this);
       this._port = socket.port;
       this._identity._initialize(socket.port, host, true);
       this._socket = socket;
     }
     catch (e)
     {
       dump("\n!!! could not start server on port " + port + ": " + e + "\n\n");
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     }
   },
 
   //
   // see nsIHttpServer.stop
   //
   stop: function(callback)
   {
     if (!callback)
       throw Cr.NS_ERROR_NULL_POINTER;
     if (!this._socket)
       throw Cr.NS_ERROR_UNEXPECTED;
 
     this._stopCallback = typeof callback === "function"
                        ? callback
                        : function() { callback.onStopped(); };
 
     dumpn(">>> stopping listening on port " + this._socket.port);
     this._socket.close();
     this._socket = null;
 
     // We can't have this identity any more, and the port on which we're running
     // this server now could be meaningless the next time around.
     this._identity._teardown();
 
     this._doQuit = false;
 
     // socket-close notification and pending request completion happen async
   },
 
   //
   // see nsIHttpServer.registerFile
   //
   registerFile: function(path, file)
   {
     if (file && (!file.exists() || file.isDirectory()))
       throw Cr.NS_ERROR_INVALID_ARG;
 
     this._handler.registerFile(path, file);
   },
 
   //
   // see nsIHttpServer.registerDirectory
   //
   registerDirectory: function(path, directory)
   {
     // XXX true path validation!
     if (path.charAt(0) != "/" ||
         path.charAt(path.length - 1) != "/" ||
         (directory &&
          (!directory.exists() || !directory.isDirectory())))
       throw Cr.NS_ERROR_INVALID_ARG;
 
     // XXX determine behavior of nonexistent /foo/bar when a /foo/bar/ mapping
     //     exists!
 
     this._handler.registerDirectory(path, directory);
   },
 
   //
   // see nsIHttpServer.registerPathHandler
   //
   registerPathHandler: function(path, handler)
   {
     this._handler.registerPathHandler(path, handler);
   },
 
   //
   // see nsIHttpServer.registerPrefixHandler
   //
   registerPrefixHandler: function(prefix, handler)
   {
     this._handler.registerPrefixHandler(prefix, handler);
   },
 
   //
   // see nsIHttpServer.registerErrorHandler
   //
   registerErrorHandler: function(code, handler)
   {
     this._handler.registerErrorHandler(code, handler);
   },
 
   //
   // see nsIHttpServer.setIndexHandler
   //
   setIndexHandler: function(handler)
   {
     this._handler.setIndexHandler(handler);
   },
 
   //
   // see nsIHttpServer.registerContentType
   //
   registerContentType: function(ext, type)
   {
     this._handler.registerContentType(ext, type);
   },
 
   //
   // see nsIHttpServer.serverIdentity
   //
   get identity()
   {
     return this._identity;
   },
 
   //
   // see nsIHttpServer.getState
   //
   getState: function(path, k)
   {
     return this._handler._getState(path, k);
   },
 
   //
   // see nsIHttpServer.setState
   //
   setState: function(path, k, v)
   {
     return this._handler._setState(path, k, v);
   },
 
   //
   // see nsIHttpServer.getSharedState
   //
   getSharedState: function(k)
   {
     return this._handler._getSharedState(k);
   },
 
   //
   // see nsIHttpServer.setSharedState
   //
   setSharedState: function(k, v)
   {
     return this._handler._setSharedState(k, v);
   },
 
   //
   // see nsIHttpServer.getObjectState
   //
   getObjectState: function(k)
   {
     return this._handler._getObjectState(k);
   },
 
   //
   // see nsIHttpServer.setObjectState
   //
   setObjectState: function(k, v)
   {
     return this._handler._setObjectState(k, v);
   },
 
 
   // NSISUPPORTS
 
   //
   // see nsISupports.QueryInterface
   //
   QueryInterface: function(iid)
   {
     if (iid.equals(Ci.nsIHttpServer) ||
         iid.equals(Ci.nsIServerSocketListener) ||
         iid.equals(Ci.nsISupports))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // NON-XPCOM PUBLIC API
 
   /**
    * Returns true iff this server is not running (and is not in the process of
    * serving any requests still to be processed when the server was last
    * stopped after being run).
    */
   isStopped: function()
   {
     return this._socketClosed && !this._hasOpenConnections();
   },
 
   // PRIVATE IMPLEMENTATION
 
   /** True if this server has any open connections to it, false otherwise. */
   _hasOpenConnections: function()
   {
     //
     // If we have any open connections, they're tracked as numeric properties on
     // |this._connections|.  The non-standard __count__ property could be used
     // to check whether there are any properties, but standard-wise, even
     // looking forward to ES5, there's no less ugly yet still O(1) way to do
     // this.
     //
     for (var n in this._connections)
       return true;
     return false;
   },
 
   /** Calls the server-stopped callback provided when stop() was called. */
   _notifyStopped: function()
   {
     NS_ASSERT(this._stopCallback !== null, "double-notifying?");
     NS_ASSERT(!this._hasOpenConnections(), "should be done serving by now");
 
     //
     // NB: We have to grab this now, null out the member, *then* call the
     //     callback here, or otherwise the callback could (indirectly) futz with
     //     this._stopCallback by starting and immediately stopping this, at
     //     which point we'd be nulling out a field we no longer have a right to
     //     modify.
     //
     var callback = this._stopCallback;
     this._stopCallback = null;
     try
     {
       callback();
     }
     catch (e)
     {
       // not throwing because this is specified as being usually (but not
       // always) asynchronous
       dump("!!! error running onStopped callback: " + e + "\n");
     }
   },
 
   /**
    * Notifies this server that the given connection has been closed.
    *
    * @param connection : Connection
    *   the connection that was closed
    */
   _connectionClosed: function(connection)
   {
     NS_ASSERT(connection.number in this._connections,
               "closing a connection " + this + " that we never added to the " +
               "set of open connections?");
     NS_ASSERT(this._connections[connection.number] === connection,
               "connection number mismatch?  " +
               this._connections[connection.number]);
     delete this._connections[connection.number];
 
     // Fire a pending server-stopped notification if it's our responsibility.
     if (!this._hasOpenConnections() && this._socketClosed)
       this._notifyStopped();
     // Bug 508125: Add a GC here else we'll use gigabytes of memory running
     // mochitests. We can't rely on xpcshell doing an automated GC, as that
     // would interfere with testing GC stuff...
     Components.utils.forceGC();
   },
 
   /**
    * Requests that the server be shut down when possible.
    */
   _requestQuit: function()
   {
     dumpn(">>> requesting a quit");
     dumpStack();
     this._doQuit = true;
   }
 };
 
 this.HttpServer = nsHttpServer;
 
 //
 // RFC 2396 section 3.2.2:
 //
 // host        = hostname | IPv4address
 // hostname    = *( domainlabel "." ) toplabel [ "." ]
 // domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum
 // toplabel    = alpha | alpha *( alphanum | "-" ) alphanum
 // IPv4address = 1*digit "." 1*digit "." 1*digit "." 1*digit
 //
 
 const HOST_REGEX =
   new RegExp("^(?:" +
                // *( domainlabel "." )
                "(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)*" +
                // toplabel
                "[a-z](?:[a-z0-9-]*[a-z0-9])?" +
              "|" +
                // IPv4 address 
                "\\d+\\.\\d+\\.\\d+\\.\\d+" +
              ")$",
              "i");
 
 
 /**
  * Represents the identity of a server.  An identity consists of a set of
  * (scheme, host, port) tuples denoted as locations (allowing a single server to
  * serve multiple sites or to be used behind both HTTP and HTTPS proxies for any
  * host/port).  Any incoming request must be to one of these locations, or it
  * will be rejected with an HTTP 400 error.  One location, denoted as the
  * primary location, is the location assigned in contexts where a location
  * cannot otherwise be endogenously derived, such as for HTTP/1.0 requests.
  *
  * A single identity may contain at most one location per unique host/port pair;
  * other than that, no restrictions are placed upon what locations may
  * constitute an identity.
  */
 function ServerIdentity()
 {
   /** The scheme of the primary location. */
   this._primaryScheme = "http";
 
   /** The hostname of the primary location. */
   this._primaryHost = "127.0.0.1"
 
   /** The port number of the primary location. */
   this._primaryPort = -1;
 
   /**
    * The current port number for the corresponding server, stored so that a new
    * primary location can always be set if the current one is removed.
    */
   this._defaultPort = -1;
 
   /**
    * Maps hosts to maps of ports to schemes, e.g. the following would represent
    * https://example.com:789/ and http://example.org/:
    *
    *   {
    *     "xexample.com": { 789: "https" },
    *     "xexample.org": { 80: "http" }
    *   }
    *
    * Note the "x" prefix on hostnames, which prevents collisions with special
    * JS names like "prototype".
    */
   this._locations = { "xlocalhost": {} };
 }
 ServerIdentity.prototype =
 {
   // NSIHTTPSERVERIDENTITY
 
   //
   // see nsIHttpServerIdentity.primaryScheme
   //
   get primaryScheme()
   {
     if (this._primaryPort === -1)
       throw Cr.NS_ERROR_NOT_INITIALIZED;
     return this._primaryScheme;
   },
 
   //
   // see nsIHttpServerIdentity.primaryHost
   //
   get primaryHost()
   {
     if (this._primaryPort === -1)
       throw Cr.NS_ERROR_NOT_INITIALIZED;
     return this._primaryHost;
   },
 
   //
   // see nsIHttpServerIdentity.primaryPort
   //
   get primaryPort()
   {
     if (this._primaryPort === -1)
       throw Cr.NS_ERROR_NOT_INITIALIZED;
     return this._primaryPort;
   },
 
   //
   // see nsIHttpServerIdentity.add
   //
   add: function(scheme, host, port)
   {
     this._validate(scheme, host, port);
 
     var entry = this._locations["x" + host];
     if (!entry)
       this._locations["x" + host] = entry = {};
 
     entry[port] = scheme;
   },
 
   //
   // see nsIHttpServerIdentity.remove
   //
   remove: function(scheme, host, port)
   {
     this._validate(scheme, host, port);
 
     var entry = this._locations["x" + host];
     if (!entry)
       return false;
 
     var present = port in entry;
     delete entry[port];
 
     if (this._primaryScheme == scheme &&
         this._primaryHost == host &&
         this._primaryPort == port &&
         this._defaultPort !== -1)
     {
       // Always keep at least one identity in existence at any time, unless
       // we're in the process of shutting down (the last condition above).
       this._primaryPort = -1;
       this._initialize(this._defaultPort, host, false);
     }
 
     return present;
   },
 
   //
   // see nsIHttpServerIdentity.has
   //
   has: function(scheme, host, port)
   {
     this._validate(scheme, host, port);
 
     return "x" + host in this._locations &&
            scheme === this._locations["x" + host][port];
   },
 
   //
   // see nsIHttpServerIdentity.has
   //
   getScheme: function(host, port)
   {
     this._validate("http", host, port);
 
     var entry = this._locations["x" + host];
     if (!entry)
       return "";
 
     return entry[port] || "";
   },
 
   //
   // see nsIHttpServerIdentity.setPrimary
   //
   setPrimary: function(scheme, host, port)
   {
     this._validate(scheme, host, port);
 
     this.add(scheme, host, port);
 
     this._primaryScheme = scheme;
     this._primaryHost = host;
     this._primaryPort = port;
   },
 
 
   // NSISUPPORTS
 
   //
   // see nsISupports.QueryInterface
   //
   QueryInterface: function(iid)
   {
     if (iid.equals(Ci.nsIHttpServerIdentity) || iid.equals(Ci.nsISupports))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // PRIVATE IMPLEMENTATION
 
   /**
    * Initializes the primary name for the corresponding server, based on the
    * provided port number.
    */
   _initialize: function(port, host, addSecondaryDefault)
   {
     this._host = host;
     if (this._primaryPort !== -1)
       this.add("http", host, port);
     else
       this.setPrimary("http", "localhost", port);
     this._defaultPort = port;
 
     // Only add this if we're being called at server startup
     if (addSecondaryDefault && host != "127.0.0.1")
       this.add("http", "127.0.0.1", port);
   },
 
   /**
    * Called at server shutdown time, unsets the primary location only if it was
    * the default-assigned location and removes the default location from the
    * set of locations used.
    */
   _teardown: function()
   {
     if (this._host != "127.0.0.1") {
       // Not the default primary location, nothing special to do here
       this.remove("http", "127.0.0.1", this._defaultPort);
     }
     
     // This is a *very* tricky bit of reasoning here; make absolutely sure the
     // tests for this code pass before you commit changes to it.
     if (this._primaryScheme == "http" &&
         this._primaryHost == this._host &&
         this._primaryPort == this._defaultPort)
     {
       // Make sure we don't trigger the readding logic in .remove(), then remove
       // the default location.
       var port = this._defaultPort;
       this._defaultPort = -1;
       this.remove("http", this._host, port);
 
       // Ensure a server start triggers the setPrimary() path in ._initialize()
       this._primaryPort = -1;
     }
     else
     {
       // No reason not to remove directly as it's not our primary location
       this.remove("http", this._host, this._defaultPort);
     }
   },
 
   /**
    * Ensures scheme, host, and port are all valid with respect to RFC 2396.
    *
    * @throws NS_ERROR_ILLEGAL_VALUE
    *   if any argument doesn't match the corresponding production
    */
   _validate: function(scheme, host, port)
   {
     if (scheme !== "http" && scheme !== "https")
     {
       dumpn("*** server only supports http/https schemes: '" + scheme + "'");
       dumpStack();
       throw Cr.NS_ERROR_ILLEGAL_VALUE;
     }
     if (!HOST_REGEX.test(host))
     {
       dumpn("*** unexpected host: '" + host + "'");
       throw Cr.NS_ERROR_ILLEGAL_VALUE;
     }
     if (port < 0 || port > 65535)
     {
       dumpn("*** unexpected port: '" + port + "'");
       throw Cr.NS_ERROR_ILLEGAL_VALUE;
     }
   }
 };
 
 
 /**
  * Represents a connection to the server (and possibly in the future the thread
  * on which the connection is processed).
  *
  * @param input : nsIInputStream
  *   stream from which incoming data on the connection is read
  * @param output : nsIOutputStream
  *   stream to write data out the connection
  * @param server : nsHttpServer
  *   the server handling the connection
  * @param port : int
  *   the port on which the server is running
  * @param outgoingPort : int
  *   the outgoing port used by this connection
  * @param number : uint
  *   a serial number used to uniquely identify this connection
  */
 function Connection(input, output, server, port, outgoingPort, number)
 {
   dumpn("*** opening new connection " + number + " on port " + outgoingPort);
 
   /** Stream of incoming data. */
   this.input = input;
 
   /** Stream for outgoing data. */
   this.output = output;
 
   /** The server associated with this request. */
   this.server = server;
 
   /** The port on which the server is running. */
   this.port = port;
 
   /** The outgoing poort used by this connection. */
   this._outgoingPort = outgoingPort;
 
   /** The serial number of this connection. */
   this.number = number;
 
   /**
    * The request for which a response is being generated, null if the
    * incoming request has not been fully received or if it had errors.
    */
   this.request = null;
 
   /** This allows a connection to disambiguate between a peer initiating a
    *  close and the socket being forced closed on shutdown.
    */
   this._closed = false;
 
   /** State variable for debugging. */
   this._processed = false;
 
   /** whether or not 1st line of request has been received */
   this._requestStarted = false; 
 }
 Connection.prototype =
 {
   /** Closes this connection's input/output streams. */
   close: function()
   {
     if (this._closed)
         return;
 
     dumpn("*** closing connection " + this.number +
           " on port " + this._outgoingPort);
 
     this.input.close();
     this.output.close();
     this._closed = true;
 
     var server = this.server;
     server._connectionClosed(this);
 
     // If an error triggered a server shutdown, act on it now
     if (server._doQuit)
       server.stop(function() { /* not like we can do anything better */ });
   },
 
   /**
    * Initiates processing of this connection, using the data in the given
    * request.
    *
    * @param request : Request
    *   the request which should be processed
    */
   process: function(request)
   {
     NS_ASSERT(!this._closed && !this._processed);
 
     this._processed = true;
 
     this.request = request;
     this.server._handler.handleResponse(this);
   },
 
   /**
    * Initiates processing of this connection, generating a response with the
    * given HTTP error code.
    *
    * @param code : uint
    *   an HTTP code, so in the range [0, 1000)
    * @param request : Request
    *   incomplete data about the incoming request (since there were errors
    *   during its processing
    */
   processError: function(code, request)
   {
     NS_ASSERT(!this._closed && !this._processed);
 
     this._processed = true;
     this.request = request;
     this.server._handler.handleError(code, this);
   },
 
   /** Converts this to a string for debugging purposes. */
   toString: function()
   {
     return "<Connection(" + this.number +
            (this.request ? ", " + this.request.path : "") +"): " +
            (this._closed ? "closed" : "open") + ">";
   },
 
   requestStarted: function()
   {
     this._requestStarted = true;
   }
 };
 
 
 
 /** Returns an array of count bytes from the given input stream. */
 function readBytes(inputStream, count)
 {
   return new BinaryInputStream(inputStream).readByteArray(count);
 }
 
 
 
 /** Request reader processing states; see RequestReader for details. */
 const READER_IN_REQUEST_LINE = 0;
 const READER_IN_HEADERS      = 1;
 const READER_IN_BODY         = 2;
 const READER_FINISHED        = 3;
 
 
 /**
  * Reads incoming request data asynchronously, does any necessary preprocessing,
  * and forwards it to the request handler.  Processing occurs in three states:
  *
  *   READER_IN_REQUEST_LINE     Reading the request's status line
  *   READER_IN_HEADERS          Reading headers in the request
  *   READER_IN_BODY             Reading the body of the request
  *   READER_FINISHED            Entire request has been read and processed
  *
  * During the first two stages, initial metadata about the request is gathered
  * into a Request object.  Once the status line and headers have been processed,
  * we start processing the body of the request into the Request.  Finally, when
  * the entire body has been read, we create a Response and hand it off to the
  * ServerHandler to be given to the appropriate request handler.
  *
  * @param connection : Connection
  *   the connection for the request being read
  */
 function RequestReader(connection)
 {
   /** Connection metadata for this request. */
   this._connection = connection;
 
   /**
    * A container providing line-by-line access to the raw bytes that make up the
    * data which has been read from the connection but has not yet been acted
    * upon (by passing it to the request handler or by extracting request
    * metadata from it).
    */
   this._data = new LineData();
 
   /**
    * The amount of data remaining to be read from the body of this request.
    * After all headers in the request have been read this is the value in the
    * Content-Length header, but as the body is read its value decreases to zero.
    */
   this._contentLength = 0;
 
   /** The current state of parsing the incoming request. */
   this._state = READER_IN_REQUEST_LINE;
 
   /** Metadata constructed from the incoming request for the request handler. */
   this._metadata = new Request(connection.port);
 
   /**
    * Used to preserve state if we run out of line data midway through a
    * multi-line header.  _lastHeaderName stores the name of the header, while
    * _lastHeaderValue stores the value we've seen so far for the header.
    *
    * These fields are always either both undefined or both strings.
    */
   this._lastHeaderName = this._lastHeaderValue = undefined;
 }
 RequestReader.prototype =
 {
   // NSIINPUTSTREAMCALLBACK
 
   /**
    * Called when more data from the incoming request is available.  This method
    * then reads the available data from input and deals with that data as
    * necessary, depending upon the syntax of already-downloaded data.
    *
    * @param input : nsIAsyncInputStream
    *   the stream of incoming data from the connection
    */
   onInputStreamReady: function(input)
   {
     dumpn("*** onInputStreamReady(input=" + input + ") on thread " +
           gThreadManager.currentThread + " (main is " +
           gThreadManager.mainThread + ")");
     dumpn("*** this._state == " + this._state);
 
     // Handle cases where we get more data after a request error has been
     // discovered but *before* we can close the connection.
     var data = this._data;
     if (!data)
       return;
 
     try
     {
       data.appendBytes(readBytes(input, input.available()));
     }
     catch (e)
     {
       if (streamClosed(e))
       {
         dumpn("*** WARNING: unexpected error when reading from socket; will " +
               "be treated as if the input stream had been closed");
         dumpn("*** WARNING: actual error was: " + e);
       }
 
       // We've lost a race -- input has been closed, but we're still expecting
       // to read more data.  available() will throw in this case, and since
       // we're dead in the water now, destroy the connection.
       dumpn("*** onInputStreamReady called on a closed input, destroying " +
             "connection");
       this._connection.close();
       return;
     }
 
     switch (this._state)
     {
       default:
         NS_ASSERT(false, "invalid state: " + this._state);
         break;
 
       case READER_IN_REQUEST_LINE:
         if (!this._processRequestLine())
           break;
         /* fall through */
 
       case READER_IN_HEADERS:
         if (!this._processHeaders())
           break;
         /* fall through */
 
       case READER_IN_BODY:
         this._processBody();
     }
 
     if (this._state != READER_FINISHED)
       input.asyncWait(this, 0, 0, gThreadManager.currentThread);
   },
 
   //
   // see nsISupports.QueryInterface
   //
   QueryInterface: function(aIID)
   {
     if (aIID.equals(Ci.nsIInputStreamCallback) ||
         aIID.equals(Ci.nsISupports))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // PRIVATE API
 
   /**
    * Processes unprocessed, downloaded data as a request line.
    *
    * @returns boolean
    *   true iff the request line has been fully processed
    */
   _processRequestLine: function()
   {
     NS_ASSERT(this._state == READER_IN_REQUEST_LINE);
 
     // Servers SHOULD ignore any empty line(s) received where a Request-Line
     // is expected (section 4.1).
     var data = this._data;
     var line = {};
     var readSuccess;
     while ((readSuccess = data.readLine(line)) && line.value == "")
       dumpn("*** ignoring beginning blank line...");
 
     // if we don't have a full line, wait until we do
     if (!readSuccess)
       return false;
 
     // we have the first non-blank line
     try
     {
       this._parseRequestLine(line.value);
       this._state = READER_IN_HEADERS;
       this._connection.requestStarted();
       return true;
     }
     catch (e)
     {
       this._handleError(e);
       return false;
     }
   },
 
   /**
    * Processes stored data, assuming it is either at the beginning or in
    * the middle of processing request headers.
    *
    * @returns boolean
    *   true iff header data in the request has been fully processed
    */
   _processHeaders: function()
   {
     NS_ASSERT(this._state == READER_IN_HEADERS);
 
     // XXX things to fix here:
     //
     // - need to support RFC 2047-encoded non-US-ASCII characters
 
     try
     {
       var done = this._parseHeaders();
       if (done)
       {
         var request = this._metadata;
 
         // XXX this is wrong for requests with transfer-encodings applied to
         //     them, particularly chunked (which by its nature can have no
         //     meaningful Content-Length header)!
         this._contentLength = request.hasHeader("Content-Length")
                             ? parseInt(request.getHeader("Content-Length"), 10)
                             : 0;
         dumpn("_processHeaders, Content-length=" + this._contentLength);
 
         this._state = READER_IN_BODY;
       }
       return done;
     }
     catch (e)
     {
       this._handleError(e);
       return false;
     }
   },
 
   /**
    * Processes stored data, assuming it is either at the beginning or in
    * the middle of processing the request body.
    *
    * @returns boolean
    *   true iff the request body has been fully processed
    */
   _processBody: function()
   {
     NS_ASSERT(this._state == READER_IN_BODY);
 
     // XXX handle chunked transfer-coding request bodies!
 
     try
     {
       if (this._contentLength > 0)
       {
         var data = this._data.purge();
         var count = Math.min(data.length, this._contentLength);
         dumpn("*** loading data=" + data + " len=" + data.length +
               " excess=" + (data.length - count));
 
         var bos = new BinaryOutputStream(this._metadata._bodyOutputStream);
         bos.writeByteArray(data, count);
         this._contentLength -= count;
       }
 
       dumpn("*** remaining body data len=" + this._contentLength);
       if (this._contentLength == 0)
       {
         this._validateRequest();
         this._state = READER_FINISHED;
         this._handleResponse();
         return true;
       }
       
       return false;
     }
     catch (e)
     {
       this._handleError(e);
       return false;
     }
   },
 
   /**
    * Does various post-header checks on the data in this request.
    *
    * @throws : HttpError
    *   if the request was malformed in some way
    */
   _validateRequest: function()
   {
     NS_ASSERT(this._state == READER_IN_BODY);
 
     dumpn("*** _validateRequest");
 
     var metadata = this._metadata;
     var headers = metadata._headers;
 
     // 19.6.1.1 -- servers MUST report 400 to HTTP/1.1 requests w/o Host header
     var identity = this._connection.server.identity;
     if (metadata._httpVersion.atLeast(nsHttpVersion.HTTP_1_1))
     {
       if (!headers.hasHeader("Host"))
       {
         dumpn("*** malformed HTTP/1.1 or greater request with no Host header!");
         throw HTTP_400;
       }
 
       // If the Request-URI wasn't absolute, then we need to determine our host.
       // We have to determine what scheme was used to access us based on the
       // server identity data at this point, because the request just doesn't
       // contain enough data on its own to do this, sadly.
       if (!metadata._host)
       {
         var host, port;
         var hostPort = headers.getHeader("Host");
         var colon = hostPort.indexOf(":");
         if (colon < 0)
         {
           host = hostPort;
           port = "";
         }
         else
         {
           host = hostPort.substring(0, colon);
           port = hostPort.substring(colon + 1);
         }
 
         // NB: We allow an empty port here because, oddly, a colon may be
         //     present even without a port number, e.g. "example.com:"; in this
         //     case the default port applies.
         if (!HOST_REGEX.test(host) || !/^\d*$/.test(port))
         {
           dumpn("*** malformed hostname (" + hostPort + ") in Host " +
                 "header, 400 time");
           throw HTTP_400;
         }
 
         // If we're not given a port, we're stuck, because we don't know what
         // scheme to use to look up the correct port here, in general.  Since
         // the HTTPS case requires a tunnel/proxy and thus requires that the
         // requested URI be absolute (and thus contain the necessary
         // information), let's assume HTTP will prevail and use that.
         port = +port || 80;
 
         var scheme = identity.getScheme(host, port);
         if (!scheme)
         {
           dumpn("*** unrecognized hostname (" + hostPort + ") in Host " +
                 "header, 400 time");
           throw HTTP_400;
         }
 
         metadata._scheme = scheme;
         metadata._host = host;
         metadata._port = port;
       }
     }
     else
     {
       NS_ASSERT(metadata._host === undefined,
                 "HTTP/1.0 doesn't allow absolute paths in the request line!");
 
       metadata._scheme = identity.primaryScheme;
       metadata._host = identity.primaryHost;
       metadata._port = identity.primaryPort;
     }
 
     NS_ASSERT(identity.has(metadata._scheme, metadata._host, metadata._port),
               "must have a location we recognize by now!");
   },
 
   /**
    * Handles responses in case of error, either in the server or in the request.
    *
    * @param e
    *   the specific error encountered, which is an HttpError in the case where
    *   the request is in some way invalid or cannot be fulfilled; if this isn't
    *   an HttpError we're going to be paranoid and shut down, because that
    *   shouldn't happen, ever
    */
   _handleError: function(e)
   {
     // Don't fall back into normal processing!
     this._state = READER_FINISHED;
 
     var server = this._connection.server;
     if (e instanceof HttpError)
     {
       var code = e.code;
     }
     else
     {
       dumpn("!!! UNEXPECTED ERROR: " + e +
             (e.lineNumber ? ", line " + e.lineNumber : ""));
 
       // no idea what happened -- be paranoid and shut down
       code = 500;
       server._requestQuit();
     }
 
     // make attempted reuse of data an error
     this._data = null;
 
     this._connection.processError(code, this._metadata);
   },
 
   /**
    * Now that we've read the request line and headers, we can actually hand off
    * the request to be handled.
    *
    * This method is called once per request, after the request line and all
    * headers and the body, if any, have been received.
    */
   _handleResponse: function()
   {
     NS_ASSERT(this._state == READER_FINISHED);
 
     // We don't need the line-based data any more, so make attempted reuse an
     // error.
     this._data = null;
 
     this._connection.process(this._metadata);
   },
 
 
   // PARSING
 
   /**
    * Parses the request line for the HTTP request associated with this.
    *
    * @param line : string
    *   the request line
    */
   _parseRequestLine: function(line)
   {
     NS_ASSERT(this._state == READER_IN_REQUEST_LINE);
 
     dumpn("*** _parseRequestLine('" + line + "')");
 
     var metadata = this._metadata;
 
     // clients and servers SHOULD accept any amount of SP or HT characters
     // between fields, even though only a single SP is required (section 19.3)
     var request = line.split(/[ \t]+/);
     if (!request || request.length != 3)
     {
       dumpn("*** No request in line");
       throw HTTP_400;
     }
 
     metadata._method = request[0];
 
     // get the HTTP version
     var ver = request[2];
     var match = ver.match(/^HTTP\/(\d+\.\d+)$/);
     if (!match)
     {
       dumpn("*** No HTTP version in line");
       throw HTTP_400;
     }
 
     // determine HTTP version
     try
     {
       metadata._httpVersion = new nsHttpVersion(match[1]);
       if (!metadata._httpVersion.atLeast(nsHttpVersion.HTTP_1_0))
         throw "unsupported HTTP version";
     }
     catch (e)
     {
       // we support HTTP/1.0 and HTTP/1.1 only
       throw HTTP_501;
     }
 
 
     var fullPath = request[1];
     var serverIdentity = this._connection.server.identity;
 
     var scheme, host, port;
 
     if (fullPath.charAt(0) != "/")
     {
       // No absolute paths in the request line in HTTP prior to 1.1
       if (!metadata._httpVersion.atLeast(nsHttpVersion.HTTP_1_1))
       {
         dumpn("*** Metadata version too low");
         throw HTTP_400;
       }
 
       try
       {
         var uri = Cc["@mozilla.org/network/io-service;1"]
                     .getService(Ci.nsIIOService)
                     .newURI(fullPath, null, null);
         fullPath = uri.path;
         scheme = uri.scheme;
         host = metadata._host = uri.asciiHost;
         port = uri.port;
         if (port === -1)
         {
           if (scheme === "http")
           {
             port = 80;
           }
           else if (scheme === "https")
           {
             port = 443;
           }
           else
           {
             dumpn("*** Unknown scheme: " + scheme);
             throw HTTP_400;
           }
         }
       }
       catch (e)
       {
         // If the host is not a valid host on the server, the response MUST be a
         // 400 (Bad Request) error message (section 5.2).  Alternately, the URI
         // is malformed.
         dumpn("*** Threw when dealing with URI: " + e);
         throw HTTP_400;
       }
 
       if (!serverIdentity.has(scheme, host, port) || fullPath.charAt(0) != "/")
       {
         dumpn("*** serverIdentity unknown or path does not start with '/'");
         throw HTTP_400;
       }
     }
 
     var splitter = fullPath.indexOf("?");
     if (splitter < 0)
     {
       // _queryString already set in ctor
       metadata._path = fullPath;
     }
     else
     {
       metadata._path = fullPath.substring(0, splitter);
       metadata._queryString = fullPath.substring(splitter + 1);
     }
 
     metadata._scheme = scheme;
     metadata._host = host;
     metadata._port = port;
   },
 
   /**
    * Parses all available HTTP headers in this until the header-ending CRLFCRLF,
    * adding them to the store of headers in the request.
    *
    * @throws
    *   HTTP_400 if the headers are malformed
    * @returns boolean
    *   true if all headers have now been processed, false otherwise
    */
   _parseHeaders: function()
   {
     NS_ASSERT(this._state == READER_IN_HEADERS);
 
     dumpn("*** _parseHeaders");
 
     var data = this._data;
 
     var headers = this._metadata._headers;
     var lastName = this._lastHeaderName;
     var lastVal = this._lastHeaderValue;
 
     var line = {};
     while (true)
     {
       dumpn("*** Last name: '" + lastName + "'");
       dumpn("*** Last val: '" + lastVal + "'");
       NS_ASSERT(!((lastVal === undefined) ^ (lastName === undefined)),
                 lastName === undefined ?
                   "lastVal without lastName?  lastVal: '" + lastVal + "'" :
                   "lastName without lastVal?  lastName: '" + lastName + "'");
 
       if (!data.readLine(line))
       {
         // save any data we have from the header we might still be processing
         this._lastHeaderName = lastName;
         this._lastHeaderValue = lastVal;
         return false;
       }
 
       var lineText = line.value;
       dumpn("*** Line text: '" + lineText + "'");
       var firstChar = lineText.charAt(0);
 
       // blank line means end of headers
       if (lineText == "")
       {
         // we're finished with the previous header
         if (lastName)
         {
           try
           {
             headers.setHeader(lastName, lastVal, true);
           }
           catch (e)
           {
             dumpn("*** setHeader threw on last header, e == " + e);
             throw HTTP_400;
           }
         }
         else
         {
           // no headers in request -- valid for HTTP/1.0 requests
         }
 
         // either way, we're done processing headers
         this._state = READER_IN_BODY;
         return true;
       }
       else if (firstChar == " " || firstChar == "\t")
       {
         // multi-line header if we've already seen a header line
         if (!lastName)
         {
           dumpn("We don't have a header to continue!");
           throw HTTP_400;
         }
 
         // append this line's text to the value; starts with SP/HT, so no need
         // for separating whitespace
         lastVal += lineText;
       }
       else
       {
         // we have a new header, so set the old one (if one existed)
         if (lastName)
         {
           try
           {
             headers.setHeader(lastName, lastVal, true);
           }
           catch (e)
           {
             dumpn("*** setHeader threw on a header, e == " + e);
             throw HTTP_400;
           }
         }
 
         var colon = lineText.indexOf(":"); // first colon must be splitter
         if (colon < 1)
         {
           dumpn("*** No colon or missing header field-name");
           throw HTTP_400;
         }
 
         // set header name, value (to be set in the next loop, usually)
         lastName = lineText.substring(0, colon);
         lastVal = lineText.substring(colon + 1);
       } // empty, continuation, start of header
     } // while (true)
   }
 };
 
 
 /** The character codes for CR and LF. */
 const CR = 0x0D, LF = 0x0A;
 
 /**
  * Calculates the number of characters before the first CRLF pair in array, or
  * -1 if the array contains no CRLF pair.
  *
  * @param array : Array
  *   an array of numbers in the range [0, 256), each representing a single
  *   character; the first CRLF is the lowest index i where
  *   |array[i] == "\r".charCodeAt(0)| and |array[i+1] == "\n".charCodeAt(0)|,
  *   if such an |i| exists, and -1 otherwise
  * @param start : uint
  *   start index from which to begin searching in array
  * @returns int
  *   the index of the first CRLF if any were present, -1 otherwise
  */
 function findCRLF(array, start)
 {
   for (var i = array.indexOf(CR, start); i >= 0; i = array.indexOf(CR, i + 1))
   {
     if (array[i + 1] == LF)
       return i;
   }
   return -1;
 }
 
 
 /**
  * A container which provides line-by-line access to the arrays of bytes with
  * which it is seeded.
  */
 function LineData()
 {
   /** An array of queued bytes from which to get line-based characters. */
   this._data = [];
 
   /** Start index from which to search for CRLF. */
   this._start = 0;
 }
 LineData.prototype =
 {
   /**
    * Appends the bytes in the given array to the internal data cache maintained
    * by this.
    */
   appendBytes: function(bytes)
   {
     var count = bytes.length;
     var quantum = 262144; // just above half SpiderMonkey's argument-count limit
     if (count < quantum)
     {
       Array.prototype.push.apply(this._data, bytes);
       return;
     }
 
     // Large numbers of bytes may cause Array.prototype.push to be called with
     // more arguments than the JavaScript engine supports.  In that case append
     // bytes in fixed-size amounts until all bytes are appended.
     for (var start = 0; start < count; start += quantum)
     {
       var slice = bytes.slice(start, Math.min(start + quantum, count));
       Array.prototype.push.apply(this._data, slice);
     }
   },
 
   /**
    * Removes and returns a line of data, delimited by CRLF, from this.
    *
    * @param out
    *   an object whose "value" property will be set to the first line of text
    *   present in this, sans CRLF, if this contains a full CRLF-delimited line
    *   of text; if this doesn't contain enough data, the value of the property
    *   is undefined
    * @returns boolean
    *   true if a full line of data could be read from the data in this, false
    *   otherwise
    */
   readLine: function(out)
   {
     var data = this._data;
     var length = findCRLF(data, this._start);
     if (length < 0)
     {
       this._start = data.length;
 
       // But if our data ends in a CR, we have to back up one, because
       // the first byte in the next packet might be an LF and if we
       // start looking at data.length we won't find it.
       if (data.length > 0 && data[data.length - 1] === CR)
         --this._start;
 
       return false;
     }
 
     // Reset for future lines.
     this._start = 0;
 
     //
     // We have the index of the CR, so remove all the characters, including
     // CRLF, from the array with splice, and convert the removed array
     // (excluding the trailing CRLF characters) into the corresponding string.
     //
     var leading = data.splice(0, length + 2);
     var quantum = 262144;
     var line = "";
     for (var start = 0; start < length; start += quantum)
     {
       var slice = leading.slice(start, Math.min(start + quantum, length));
       line += String.fromCharCode.apply(null, slice);
     }
 
     out.value = line;
     return true;
   },
 
   /**
    * Removes the bytes currently within this and returns them in an array.
    *
    * @returns Array
    *   the bytes within this when this method is called
    */
   purge: function()
   {
     var data = this._data;
     this._data = [];
     return data;
   }
 };
 
 
 
 /**
  * Creates a request-handling function for an nsIHttpRequestHandler object.
  */
 function createHandlerFunc(handler)
 {
   return function(metadata, response) { handler.handle(metadata, response); };
 }
 
 
 /**
  * The default handler for directories; writes an HTML response containing a
  * slightly-formatted directory listing.
  */
 function defaultIndexHandler(metadata, response)
 {
   response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
   var path = htmlEscape(decodeURI(metadata.path));
 
   //
   // Just do a very basic bit of directory listings -- no need for too much
   // fanciness, especially since we don't have a style sheet in which we can
   // stick rules (don't want to pollute the default path-space).
   //
 
   var body = '<html>\
                 <head>\
                   <title>' + path + '</title>\
                 </head>\
                 <body>\
                   <h1>' + path + '</h1>\
                   <ol style="list-style-type: none">';
 
   var directory = metadata.getProperty("directory");
   NS_ASSERT(directory && directory.isDirectory());
 
   var fileList = [];
   var files = directory.directoryEntries;
   while (files.hasMoreElements())
   {
     var f = files.getNext().QueryInterface(Ci.nsIFile);
     var name = f.leafName;
     if (!f.isHidden() &&
         (name.charAt(name.length - 1) != HIDDEN_CHAR ||
          name.charAt(name.length - 2) == HIDDEN_CHAR))
       fileList.push(f);
   }
 
   fileList.sort(fileSort);
 
   for (var i = 0; i < fileList.length; i++)
   {
     var file = fileList[i];
     try
     {
       var name = file.leafName;
       if (name.charAt(name.length - 1) == HIDDEN_CHAR)
         name = name.substring(0, name.length - 1);
       var sep = file.isDirectory() ? "/" : "";
 
       // Note: using " to delimit the attribute here because encodeURIComponent
       //       passes through '.
       var item = '<li><a href="' + encodeURIComponent(name) + sep + '">' +
                    htmlEscape(name) + sep +
                  '</a></li>';
 
       body += item;
     }
     catch (e) { /* some file system error, ignore the file */ }
   }
 
   body    += '    </ol>\
                 </body>\
               </html>';
 
   response.bodyOutputStream.write(body, body.length);
 }
 
 /**
  * Sorts a and b (nsIFile objects) into an aesthetically pleasing order.
  */
 function fileSort(a, b)
 {
   var dira = a.isDirectory(), dirb = b.isDirectory();
 
   if (dira && !dirb)
     return -1;
   if (dirb && !dira)
     return 1;
 
   var namea = a.leafName.toLowerCase(), nameb = b.leafName.toLowerCase();
   return nameb > namea ? -1 : 1;
 }
 
 
 /**
  * Converts an externally-provided path into an internal path for use in
  * determining file mappings.
  *
  * @param path
  *   the path to convert
  * @param encoded
  *   true if the given path should be passed through decodeURI prior to
  *   conversion
  * @throws URIError
  *   if path is incorrectly encoded
  */
 function toInternalPath(path, encoded)
 {
   if (encoded)
     path = decodeURI(path);
 
   var comps = path.split("/");
   for (var i = 0, sz = comps.length; i < sz; i++)
   {
     var comp = comps[i];
     if (comp.charAt(comp.length - 1) == HIDDEN_CHAR)
       comps[i] = comp + HIDDEN_CHAR;
   }
   return comps.join("/");
 }
 
 const PERMS_READONLY = (4 << 6) | (4 << 3) | 4;
 
 /**
  * Adds custom-specified headers for the given file to the given response, if
  * any such headers are specified.
  *
  * @param file
  *   the file on the disk which is to be written
  * @param metadata
  *   metadata about the incoming request
  * @param response
  *   the Response to which any specified headers/data should be written
  * @throws HTTP_500
  *   if an error occurred while processing custom-specified headers
  */
 function maybeAddHeaders(file, metadata, response)
 {
   var name = file.leafName;
   if (name.charAt(name.length - 1) == HIDDEN_CHAR)
     name = name.substring(0, name.length - 1);
 
   var headerFile = file.parent;
   headerFile.append(name + HEADERS_SUFFIX);
 
   if (!headerFile.exists())
     return;
 
   const PR_RDONLY = 0x01;
   var fis = new FileInputStream(headerFile, PR_RDONLY, PERMS_READONLY,
                                 Ci.nsIFileInputStream.CLOSE_ON_EOF);
 
   try
   {
     var lis = new ConverterInputStream(fis, "UTF-8", 1024, 0x0);
     lis.QueryInterface(Ci.nsIUnicharLineInputStream);
 
     var line = {value: ""};
     var more = lis.readLine(line);
 
     if (!more && line.value == "")
       return;
 
 
     // request line
 
     var status = line.value;
     if (status.indexOf("HTTP ") == 0)
     {
       status = status.substring(5);
       var space = status.indexOf(" ");
       var code, description;
       if (space < 0)
       {
         code = status;
         description = "";
       }
       else
       {
         code = status.substring(0, space);
         description = status.substring(space + 1, status.length);
       }
     
       response.setStatusLine(metadata.httpVersion, parseInt(code, 10), description);
 
       line.value = "";
       more = lis.readLine(line);
     }
 
     // headers
     while (more || line.value != "")
     {
       var header = line.value;
       var colon = header.indexOf(":");
 
       response.setHeader(header.substring(0, colon),
                          header.substring(colon + 1, header.length),
                          false); // allow overriding server-set headers
 
       line.value = "";
       more = lis.readLine(line);
     }
   }
   catch (e)
   {
     dumpn("WARNING: error in headers for " + metadata.path + ": " + e);
     throw HTTP_500;
   }
   finally
   {
     fis.close();
   }
 }
 
 
 /**
  * An object which handles requests for a server, executing default and
  * overridden behaviors as instructed by the code which uses and manipulates it.
  * Default behavior includes the paths / and /trace (diagnostics), with some
  * support for HTTP error pages for various codes and fallback to HTTP 500 if
  * those codes fail for any reason.
  *
  * @param server : nsHttpServer
  *   the server in which this handler is being used
  */
 function ServerHandler(server)
 {
   // FIELDS
 
   /**
    * The nsHttpServer instance associated with this handler.
    */
   this._server = server;
 
   /**
    * A FileMap object containing the set of path->nsILocalFile mappings for
    * all directory mappings set in the server (e.g., "/" for /var/www/html/,
    * "/foo/bar/" for /local/path/, and "/foo/bar/baz/" for /local/path2).
    *
    * Note carefully: the leading and trailing "/" in each path (not file) are
    * removed before insertion to simplify the code which uses this.  You have
    * been warned!
    */
   this._pathDirectoryMap = new FileMap();
 
   /**
    * Custom request handlers for the server in which this resides.  Path-handler
    * pairs are stored as property-value pairs in this property.
    *
    * @see ServerHandler.prototype._defaultPaths
    */
   this._overridePaths = {};
 
   /**
    * Custom request handlers for the path prefixes on the server in which this
    * resides.  Path-handler pairs are stored as property-value pairs in this
    * property.
    *
    * @see ServerHandler.prototype._defaultPaths
    */
   this._overridePrefixes = {};
 
   /**
    * Custom request handlers for the error handlers in the server in which this
    * resides.  Path-handler pairs are stored as property-value pairs in this
    * property.
    *
    * @see ServerHandler.prototype._defaultErrors
    */
   this._overrideErrors = {};
 
   /**
    * Maps file extensions to their MIME types in the server, overriding any
    * mapping that might or might not exist in the MIME service.
    */
   this._mimeMappings = {};
 
   /**
    * The default handler for requests for directories, used to serve directories
    * when no index file is present.
    */
   this._indexHandler = defaultIndexHandler;
 
   /** Per-path state storage for the server. */
   this._state = {};
 
   /** Entire-server state storage. */
   this._sharedState = {};
 
   /** Entire-server state storage for nsISupports values. */
   this._objectState = {};
 }
 ServerHandler.prototype =
 {
   // PUBLIC API
 
   /**
    * Handles a request to this server, responding to the request appropriately
    * and initiating server shutdown if necessary.
    *
    * This method never throws an exception.
    *
    * @param connection : Connection
    *   the connection for this request
    */
   handleResponse: function(connection)
   {
     var request = connection.request;
     var response = new Response(connection);
 
     var path = request.path;
     dumpn("*** path == " + path);
 
     try
     {
       try
       {
         if (path in this._overridePaths)
         {
           // explicit paths first, then files based on existing directory mappings,
           // then (if the file doesn't exist) built-in server default paths
           dumpn("calling override for " + path);
           this._overridePaths[path](request, response);
         }
         else
         {
           var longestPrefix = "";
           for (let prefix in this._overridePrefixes) {
             if (prefix.length > longestPrefix.length &&
                 path.substr(0, prefix.length) == prefix)
             {
               longestPrefix = prefix;
             }
           }
           if (longestPrefix.length > 0)
           {
             dumpn("calling prefix override for " + longestPrefix);
             this._overridePrefixes[longestPrefix](request, response);
           }
           else
           {
             this._handleDefault(request, response);
           }
         }
       }
       catch (e)
       {
         if (response.partiallySent())
         {
           response.abort(e);
           return;
         }
 
         if (!(e instanceof HttpError))
         {
           dumpn("*** unexpected error: e == " + e);
           throw HTTP_500;
         }
         if (e.code !== 404)
           throw e;
 
         dumpn("*** default: " + (path in this._defaultPaths));
 
         response = new Response(connection);
         if (path in this._defaultPaths)
           this._defaultPaths[path](request, response);
         else
           throw HTTP_404;
       }
     }
     catch (e)
     {
       if (response.partiallySent())
       {
         response.abort(e);
         return;
       }
 
       var errorCode = "internal";
 
       try
       {
         if (!(e instanceof HttpError))
           throw e;
 
         errorCode = e.code;
         dumpn("*** errorCode == " + errorCode);
 
         response = new Response(connection);
         if (e.customErrorHandling)
           e.customErrorHandling(response);
         this._handleError(errorCode, request, response);
         return;
       }
       catch (e2)
       {
         dumpn("*** error handling " + errorCode + " error: " +
               "e2 == " + e2 + ", shutting down server");
 
         connection.server._requestQuit();
         response.abort(e2);
         return;
       }
     }
 
     response.complete();
   },
 
   //
   // see nsIHttpServer.registerFile
   //
   registerFile: function(path, file)
   {
     if (!file)
     {
       dumpn("*** unregistering '" + path + "' mapping");
       delete this._overridePaths[path];
       return;
     }
 
     dumpn("*** registering '" + path + "' as mapping to " + file.path);
     file = file.clone();
 
     var self = this;
     this._overridePaths[path] =
       function(request, response)
       {
         if (!file.exists())
           throw HTTP_404;
 
         response.setStatusLine(request.httpVersion, 200, "OK");
         self._writeFileResponse(request, file, response, 0, file.fileSize);
       };
   },
 
   //
   // see nsIHttpServer.registerPathHandler
   //
   registerPathHandler: function(path, handler)
   {
     // XXX true path validation!
     if (path.charAt(0) != "/")
       throw Cr.NS_ERROR_INVALID_ARG;
 
     this._handlerToField(handler, this._overridePaths, path);
   },
 
   //
   // see nsIHttpServer.registerPrefixHandler
   //
   registerPrefixHandler: function(path, handler)
   {
     // XXX true path validation!
     if (path.charAt(0) != "/" || path.charAt(path.length - 1) != "/")
       throw Cr.NS_ERROR_INVALID_ARG;
 
     this._handlerToField(handler, this._overridePrefixes, path);
   },
 
   //
   // see nsIHttpServer.registerDirectory
   //
   registerDirectory: function(path, directory)
   {
     // strip off leading and trailing '/' so that we can use lastIndexOf when
     // determining exactly how a path maps onto a mapped directory --
     // conditional is required here to deal with "/".substring(1, 0) being
     // converted to "/".substring(0, 1) per the JS specification
     var key = path.length == 1 ? "" : path.substring(1, path.length - 1);
 
     // the path-to-directory mapping code requires that the first character not
     // be "/", or it will go into an infinite loop
     if (key.charAt(0) == "/")
       throw Cr.NS_ERROR_INVALID_ARG;
 
     key = toInternalPath(key, false);
 
     if (directory)
     {
       dumpn("*** mapping '" + path + "' to the location " + directory.path);
       this._pathDirectoryMap.put(key, directory);
     }
     else
     {
       dumpn("*** removing mapping for '" + path + "'");
       this._pathDirectoryMap.put(key, null);
     }
   },
 
   //
   // see nsIHttpServer.registerErrorHandler
   //
   registerErrorHandler: function(err, handler)
   {
     if (!(err in HTTP_ERROR_CODES))
       dumpn("*** WARNING: registering non-HTTP/1.1 error code " +
             "(" + err + ") handler -- was this intentional?");
 
     this._handlerToField(handler, this._overrideErrors, err);
   },
 
   //
   // see nsIHttpServer.setIndexHandler
   //
   setIndexHandler: function(handler)
   {
     if (!handler)
       handler = defaultIndexHandler;
     else if (typeof(handler) != "function")
       handler = createHandlerFunc(handler);
 
     this._indexHandler = handler;
   },
 
   //
   // see nsIHttpServer.registerContentType
   //
   registerContentType: function(ext, type)
   {
     if (!type)
       delete this._mimeMappings[ext];
     else
       this._mimeMappings[ext] = headerUtils.normalizeFieldValue(type);
   },
 
   // PRIVATE API
 
   /**
    * Sets or remove (if handler is null) a handler in an object with a key.
    *
    * @param handler
    *   a handler, either function or an nsIHttpRequestHandler
    * @param dict
    *   The object to attach the handler to.
    * @param key
    *   The field name of the handler.
    */
   _handlerToField: function(handler, dict, key)
   {
     // for convenience, handler can be a function if this is run from xpcshell
     if (typeof(handler) == "function")
       dict[key] = handler;
     else if (handler)
       dict[key] = createHandlerFunc(handler);
     else
       delete dict[key];
   },
 
   /**
    * Handles a request which maps to a file in the local filesystem (if a base
    * path has already been set; otherwise the 404 error is thrown).
    *
    * @param metadata : Request
    *   metadata for the incoming request
    * @param response : Response
    *   an uninitialized Response to the given request, to be initialized by a
    *   request handler
    * @throws HTTP_###
    *   if an HTTP error occurred (usually HTTP_404); note that in this case the
    *   calling code must handle post-processing of the response
    */
   _handleDefault: function(metadata, response)
   {
     dumpn("*** _handleDefault()");
 
     response.setStatusLine(metadata.httpVersion, 200, "OK");
 
     var path = metadata.path;
     NS_ASSERT(path.charAt(0) == "/", "invalid path: <" + path + ">");
 
     // determine the actual on-disk file; this requires finding the deepest
     // path-to-directory mapping in the requested URL
     var file = this._getFileForPath(path);
 
     // the "file" might be a directory, in which case we either serve the
     // contained index.html or make the index handler write the response
     if (file.exists() && file.isDirectory())
     {
       file.append("index.html"); // make configurable?
       if (!file.exists() || file.isDirectory())
       {
         metadata._ensurePropertyBag();
         metadata._bag.setPropertyAsInterface("directory", file.parent);
         this._indexHandler(metadata, response);
         return;
       }
     }
 
     // alternately, the file might not exist
     if (!file.exists())
       throw HTTP_404;
 
     var start, end;
     if (metadata._httpVersion.atLeast(nsHttpVersion.HTTP_1_1) &&
         metadata.hasHeader("Range") &&
         this._getTypeFromFile(file) !== SJS_TYPE)
     {
       var rangeMatch = metadata.getHeader("Range").match(/^bytes=(\d+)?-(\d+)?$/);
       if (!rangeMatch)
       {
         dumpn("*** Range header bogosity: '" + metadata.getHeader("Range") + "'");
         throw HTTP_400;
       }
 
       if (rangeMatch[1] !== undefined)
         start = parseInt(rangeMatch[1], 10);
 
       if (rangeMatch[2] !== undefined)
         end = parseInt(rangeMatch[2], 10);
 
       if (start === undefined && end === undefined)
       {
         dumpn("*** More Range header bogosity: '" + metadata.getHeader("Range") + "'");
         throw HTTP_400;
       }
 
       // No start given, so the end is really the count of bytes from the
       // end of the file.
       if (start === undefined)
       {
         start = Math.max(0, file.fileSize - end);
         end   = file.fileSize - 1;
       }
 
       // start and end are inclusive
       if (end === undefined || end >= file.fileSize)
         end = file.fileSize - 1;
 
       if (start !== undefined && start >= file.fileSize) {
         var HTTP_416 = new HttpError(416, "Requested Range Not Satisfiable");
         HTTP_416.customErrorHandling = function(errorResponse)
         {
           maybeAddHeaders(file, metadata, errorResponse);
         };
         throw HTTP_416;
       }
 
       if (end < start)
       {
         response.setStatusLine(metadata.httpVersion, 200, "OK");
         start = 0;
         end = file.fileSize - 1;
       }
       else
       {
         response.setStatusLine(metadata.httpVersion, 206, "Partial Content");
         var contentRange = "bytes " + start + "-" + end + "/" + file.fileSize;
         response.setHeader("Content-Range", contentRange);
       }
     }
     else
     {
       start = 0;
       end = file.fileSize - 1;
     }
 
     // finally...
     dumpn("*** handling '" + path + "' as mapping to " + file.path + " from " +
           start + " to " + end + " inclusive");
     this._writeFileResponse(metadata, file, response, start, end - start + 1);
   },
 
   /**
    * Writes an HTTP response for the given file, including setting headers for
    * file metadata.
    *
    * @param metadata : Request
    *   the Request for which a response is being generated
    * @param file : nsILocalFile
    *   the file which is to be sent in the response
    * @param response : Response
    *   the response to which the file should be written
    * @param offset: uint
    *   the byte offset to skip to when writing
    * @param count: uint
    *   the number of bytes to write
    */
   _writeFileResponse: function(metadata, file, response, offset, count)
   {
     const PR_RDONLY = 0x01;
 
     var type = this._getTypeFromFile(file);
     if (type === SJS_TYPE)
     {
       var fis = new FileInputStream(file, PR_RDONLY, PERMS_READONLY,
                                     Ci.nsIFileInputStream.CLOSE_ON_EOF);
 
       try
       {
         var sis = new ScriptableInputStream(fis);
         var s = Cu.Sandbox(gGlobalObject);
         s.importFunction(dump, "dump");
         s.importFunction(atob, "atob");
         s.importFunction(btoa, "btoa");
 
         // Define a basic key-value state-preservation API across requests, with
         // keys initially corresponding to the empty string.
         var self = this;
         var path = metadata.path;
         s.importFunction(function getState(k)
         {
           return self._getState(path, k);
         });
         s.importFunction(function setState(k, v)
         {
           self._setState(path, k, v);
         });
         s.importFunction(function getSharedState(k)
         {
           return self._getSharedState(k);
         });
         s.importFunction(function setSharedState(k, v)
         {
           self._setSharedState(k, v);
         });
         s.importFunction(function getObjectState(k, callback)
         {
           callback(self._getObjectState(k));
         });
         s.importFunction(function setObjectState(k, v)
         {
           self._setObjectState(k, v);
         });
         s.importFunction(function registerPathHandler(p, h)
         {
           self.registerPathHandler(p, h);
         });
 
         // Make it possible for sjs files to access their location
         this._setState(path, "__LOCATION__", file.path);
 
         try
         {
           // Alas, the line number in errors dumped to console when calling the
           // request handler is simply an offset from where we load the SJS file.
           // Work around this in a reasonably non-fragile way by dynamically
           // getting the line number where we evaluate the SJS file.  Don't
           // separate these two lines!
           var line = new Error().lineNumber;
           Cu.evalInSandbox(sis.read(file.fileSize), s, "latest");
         }
         catch (e)
         {
           dumpn("*** syntax error in SJS at " + file.path + ": " + e);
           throw HTTP_500;
         }
 
         try
         {
           s.handleRequest(metadata, response);
         }
         catch (e)
         {
           dump("*** error running SJS at " + file.path + ": " +
                e + " on line " +
                (e instanceof Error
                ? e.lineNumber + " in httpd.js"
                : (e.lineNumber - line)) + "\n");
           throw HTTP_500;
         }
       }
       finally
       {
         fis.close();
       }
     }
     else
     {
       try
       {
         response.setHeader("Last-Modified",
                            toDateString(file.lastModifiedTime),
                            false);
       }
       catch (e) { /* lastModifiedTime threw, ignore */ }
 
       response.setHeader("Content-Type", type, false);
       maybeAddHeaders(file, metadata, response);
       response.setHeader("Content-Length", "" + count, false);
 
       var fis = new FileInputStream(file, PR_RDONLY, PERMS_READONLY,
                                     Ci.nsIFileInputStream.CLOSE_ON_EOF);
 
       offset = offset || 0;
       count  = count || file.fileSize;
       NS_ASSERT(offset === 0 || offset < file.fileSize, "bad offset");
       NS_ASSERT(count >= 0, "bad count");
       NS_ASSERT(offset + count <= file.fileSize, "bad total data size");
 
       try
       {
         if (offset !== 0)
         {
           // Seek (or read, if seeking isn't supported) to the correct offset so
           // the data sent to the client matches the requested range.
           if (fis instanceof Ci.nsISeekableStream)
             fis.seek(Ci.nsISeekableStream.NS_SEEK_SET, offset);
           else
             new ScriptableInputStream(fis).read(offset);
         }
       }
       catch (e)
       {
         fis.close();
         throw e;
       }
 
       let writeMore = function () {
         gThreadManager.currentThread
                       .dispatch(writeData, Ci.nsIThread.DISPATCH_NORMAL);
       }
 
       var input = new BinaryInputStream(fis);
       var output = new BinaryOutputStream(response.bodyOutputStream);
       var writeData =
         {
           run: function()
           {
             var chunkSize = Math.min(65536, count);
             count -= chunkSize;
             NS_ASSERT(count >= 0, "underflow");
 
             try
             {
               var data = input.readByteArray(chunkSize);
               NS_ASSERT(data.length === chunkSize,
                         "incorrect data returned?  got " + data.length +
                         ", expected " + chunkSize);
               output.writeByteArray(data, data.length);
               if (count === 0)
               {
                 fis.close();
                 response.finish();
               }
               else
               {
                 writeMore();
               }
             }
             catch (e)
             {
               try
               {
                 fis.close();
               }
               finally
               {
                 response.finish();
               }
               throw e;
             }
           }
         };
 
       writeMore();
 
       // Now that we know copying will start, flag the response as async.
       response.processAsync();
     }
   },
 
   /**
    * Get the value corresponding to a given key for the given path for SJS state
    * preservation across requests.
    *
    * @param path : string
    *   the path from which the given state is to be retrieved
    * @param k : string
    *   the key whose corresponding value is to be returned
    * @returns string
    *   the corresponding value, which is initially the empty string
    */
   _getState: function(path, k)
   {
     var state = this._state;
     if (path in state && k in state[path])
       return state[path][k];
     return "";
   },
 
   /**
    * Set the value corresponding to a given key for the given path for SJS state
    * preservation across requests.
    *
    * @param path : string
    *   the path from which the given state is to be retrieved
    * @param k : string
    *   the key whose corresponding value is to be set
    * @param v : string
    *   the value to be set
    */
   _setState: function(path, k, v)
   {
     if (typeof v !== "string")
       throw new Error("non-string value passed");
     var state = this._state;
     if (!(path in state))
       state[path] = {};
     state[path][k] = v;
   },
 
   /**
    * Get the value corresponding to a given key for SJS state preservation
    * across requests.
    *
    * @param k : string
    *   the key whose corresponding value is to be returned
    * @returns string
    *   the corresponding value, which is initially the empty string
    */
   _getSharedState: function(k)
   {
     var state = this._sharedState;
     if (k in state)
       return state[k];
     return "";
   },
 
   /**
    * Set the value corresponding to a given key for SJS state preservation
    * across requests.
    *
    * @param k : string
    *   the key whose corresponding value is to be set
    * @param v : string
    *   the value to be set
    */
   _setSharedState: function(k, v)
   {
     if (typeof v !== "string")
       throw new Error("non-string value passed");
     this._sharedState[k] = v;
   },
 
   /**
    * Returns the object associated with the given key in the server for SJS
    * state preservation across requests.
    *
    * @param k : string
    *  the key whose corresponding object is to be returned
    * @returns nsISupports
    *  the corresponding object, or null if none was present
    */
   _getObjectState: function(k)
   {
     if (typeof k !== "string")
       throw new Error("non-string key passed");
     return this._objectState[k] || null;
   },
 
   /**
    * Sets the object associated with the given key in the server for SJS
    * state preservation across requests.
    *
    * @param k : string
    *  the key whose corresponding object is to be set
    * @param v : nsISupports
    *  the object to be associated with the given key; may be null
    */
   _setObjectState: function(k, v)
   {
     if (typeof k !== "string")
       throw new Error("non-string key passed");
     if (typeof v !== "object")
       throw new Error("non-object value passed");
     if (v && !("QueryInterface" in v))
     {
       throw new Error("must pass an nsISupports; use wrappedJSObject to ease " +
                       "pain when using the server from JS");
     }
 
     this._objectState[k] = v;
   },
 
   /**
    * Gets a content-type for the given file, first by checking for any custom
    * MIME-types registered with this handler for the file's extension, second by
    * asking the global MIME service for a content-type, and finally by failing
    * over to application/octet-stream.
    *
    * @param file : nsIFile
    *   the nsIFile for which to get a file type
    * @returns string
    *   the best content-type which can be determined for the file
    */
   _getTypeFromFile: function(file)
   {
     try
     {
       var name = file.leafName;
       var dot = name.lastIndexOf(".");
       if (dot > 0)
       {
         var ext = name.slice(dot + 1);
         if (ext in this._mimeMappings)
           return this._mimeMappings[ext];
       }
       return Cc["@mozilla.org/uriloader/external-helper-app-service;1"]
                .getService(Ci.nsIMIMEService)
                .getTypeFromFile(file);
     }
     catch (e)
     {
       return "application/octet-stream";
     }
   },
 
   /**
    * Returns the nsILocalFile which corresponds to the path, as determined using
    * all registered path->directory mappings and any paths which are explicitly
    * overridden.
    *
    * @param path : string
    *   the server path for which a file should be retrieved, e.g. "/foo/bar"
    * @throws HttpError
    *   when the correct action is the corresponding HTTP error (i.e., because no
    *   mapping was found for a directory in path, the referenced file doesn't
    *   exist, etc.)
    * @returns nsILocalFile
    *   the file to be sent as the response to a request for the path
    */
   _getFileForPath: function(path)
   {
     // decode and add underscores as necessary
     try
     {
       path = toInternalPath(path, true);
     }
     catch (e)
     {
       dumpn("*** toInternalPath threw " + e);
       throw HTTP_400; // malformed path
     }
 
     // next, get the directory which contains this path
     var pathMap = this._pathDirectoryMap;
 
     // An example progression of tmp for a path "/foo/bar/baz/" might be:
     // "foo/bar/baz/", "foo/bar/baz", "foo/bar", "foo", ""
     var tmp = path.substring(1);
     while (true)
     {
       // do we have a match for current head of the path?
       var file = pathMap.get(tmp);
       if (file)
       {
         // XXX hack; basically disable showing mapping for /foo/bar/ when the
         //     requested path was /foo/bar, because relative links on the page
         //     will all be incorrect -- we really need the ability to easily
         //     redirect here instead
         if (tmp == path.substring(1) &&
             tmp.length != 0 &&
             tmp.charAt(tmp.length - 1) != "/")
           file = null;
         else
           break;
       }
 
       // if we've finished trying all prefixes, exit
       if (tmp == "")
         break;
 
       tmp = tmp.substring(0, tmp.lastIndexOf("/"));
     }
 
     // no mapping applies, so 404
     if (!file)
       throw HTTP_404;
 
 
     // last, get the file for the path within the determined directory
     var parentFolder = file.parent;
     var dirIsRoot = (parentFolder == null);
 
     // Strategy here is to append components individually, making sure we
     // never move above the given directory; this allows paths such as
     // "<file>/foo/../bar" but prevents paths such as "<file>/../base-sibling";
     // this component-wise approach also means the code works even on platforms
     // which don't use "/" as the directory separator, such as Windows
     var leafPath = path.substring(tmp.length + 1);
     var comps = leafPath.split("/");
     for (var i = 0, sz = comps.length; i < sz; i++)
     {
       var comp = comps[i];
 
       if (comp == "..")
         file = file.parent;
       else if (comp == "." || comp == "")
         continue;
       else
         file.append(comp);
 
       if (!dirIsRoot && file.equals(parentFolder))
         throw HTTP_403;
     }
 
     return file;
   },
 
   /**
    * Writes the error page for the given HTTP error code over the given
    * connection.
    *
    * @param errorCode : uint
    *   the HTTP error code to be used
    * @param connection : Connection
    *   the connection on which the error occurred
    */
   handleError: function(errorCode, connection)
   {
     var response = new Response(connection);
 
     dumpn("*** error in request: " + errorCode);
 
     this._handleError(errorCode, new Request(connection.port), response);
   }, 
 
   /**
    * Handles a request which generates the given error code, using the
    * user-defined error handler if one has been set, gracefully falling back to
    * the x00 status code if the code has no handler, and failing to status code
    * 500 if all else fails.
    *
    * @param errorCode : uint
    *   the HTTP error which is to be returned
    * @param metadata : Request
    *   metadata for the request, which will often be incomplete since this is an
    *   error
    * @param response : Response
    *   an uninitialized Response should be initialized when this method
    *   completes with information which represents the desired error code in the
    *   ideal case or a fallback code in abnormal circumstances (i.e., 500 is a
    *   fallback for 505, per HTTP specs)
    */
   _handleError: function(errorCode, metadata, response)
   {
     if (!metadata)
       throw Cr.NS_ERROR_NULL_POINTER;
 
     var errorX00 = errorCode - (errorCode % 100);
 
     try
     {
       if (!(errorCode in HTTP_ERROR_CODES))
         dumpn("*** WARNING: requested invalid error: " + errorCode);
 
       // RFC 2616 says that we should try to handle an error by its class if we
       // can't otherwise handle it -- if that fails, we revert to handling it as
       // a 500 internal server error, and if that fails we throw and shut down
       // the server
 
       // actually handle the error
       try
       {
         if (errorCode in this._overrideErrors)
           this._overrideErrors[errorCode](metadata, response);
         else
           this._defaultErrors[errorCode](metadata, response);
       }
       catch (e)
       {
         if (response.partiallySent())
         {
           response.abort(e);
           return;
         }
 
         // don't retry the handler that threw
         if (errorX00 == errorCode)
           throw HTTP_500;
 
         dumpn("*** error in handling for error code " + errorCode + ", " +
               "falling back to " + errorX00 + "...");
         response = new Response(response._connection);
         if (errorX00 in this._overrideErrors)
           this._overrideErrors[errorX00](metadata, response);
         else if (errorX00 in this._defaultErrors)
           this._defaultErrors[errorX00](metadata, response);
         else
           throw HTTP_500;
       }
     }
     catch (e)
     {
       if (response.partiallySent())
       {
         response.abort();
         return;
       }
 
       // we've tried everything possible for a meaningful error -- now try 500
       dumpn("*** error in handling for error code " + errorX00 + ", falling " +
             "back to 500...");
 
       try
       {
         response = new Response(response._connection);
         if (500 in this._overrideErrors)
           this._overrideErrors[500](metadata, response);
         else
           this._defaultErrors[500](metadata, response);
       }
       catch (e2)
       {
         dumpn("*** multiple errors in default error handlers!");
         dumpn("*** e == " + e + ", e2 == " + e2);
         response.abort(e2);
         return;
       }
     }
 
     response.complete();
   },
 
   // FIELDS
 
   /**
    * This object contains the default handlers for the various HTTP error codes.
    */
   _defaultErrors:
   {
     400: function(metadata, response)
     {
       // none of the data in metadata is reliable, so hard-code everything here
       response.setStatusLine("1.1", 400, "Bad Request");
       response.setHeader("Content-Type", "text/plain;charset=utf-8", false);
 
       var body = "Bad request\n";
       response.bodyOutputStream.write(body, body.length);
     },
     403: function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion, 403, "Forbidden");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>403 Forbidden</title></head>\
                     <body>\
                       <h1>403 Forbidden</h1>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     },
     404: function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion, 404, "Not Found");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>404 Not Found</title></head>\
                     <body>\
                       <h1>404 Not Found</h1>\
                       <p>\
                         <span style='font-family: monospace;'>" +
                           htmlEscape(metadata.path) +
                        "</span> was not found.\
                       </p>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     },
     416: function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion,
                             416,
                             "Requested Range Not Satisfiable");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                    <head>\
                     <title>416 Requested Range Not Satisfiable</title></head>\
                     <body>\
                      <h1>416 Requested Range Not Satisfiable</h1>\
                      <p>The byte range was not valid for the\
                         requested resource.\
                      </p>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     },
     500: function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion,
                              500,
                              "Internal Server Error");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>500 Internal Server Error</title></head>\
                     <body>\
                       <h1>500 Internal Server Error</h1>\
                       <p>Something's broken in this server and\
                         needs to be fixed.</p>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     },
     501: function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion, 501, "Not Implemented");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>501 Not Implemented</title></head>\
                     <body>\
                       <h1>501 Not Implemented</h1>\
                       <p>This server is not (yet) Apache.</p>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     },
     505: function(metadata, response)
     {
       response.setStatusLine("1.1", 505, "HTTP Version Not Supported");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>505 HTTP Version Not Supported</title></head>\
                     <body>\
                       <h1>505 HTTP Version Not Supported</h1>\
                       <p>This server only supports HTTP/1.0 and HTTP/1.1\
                         connections.</p>\
                     </body>\
                   </html>";
       response.bodyOutputStream.write(body, body.length);
     }
   },
 
   /**
    * Contains handlers for the default set of URIs contained in this server.
    */
   _defaultPaths:
   {
     "/": function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion, 200, "OK");
       response.setHeader("Content-Type", "text/html;charset=utf-8", false);
 
       var body = "<html>\
                     <head><title>httpd.js</title></head>\
                     <body>\
                       <h1>httpd.js</h1>\
                       <p>If you're seeing this page, httpd.js is up and\
                         serving requests!  Now set a base path and serve some\
                         files!</p>\
                     </body>\
                   </html>";
 
       response.bodyOutputStream.write(body, body.length);
     },
 
     "/trace": function(metadata, response)
     {
       response.setStatusLine(metadata.httpVersion, 200, "OK");
       response.setHeader("Content-Type", "text/plain;charset=utf-8", false);
 
       var body = "Request-URI: " +
                  metadata.scheme + "://" + metadata.host + ":" + metadata.port +
                  metadata.path + "\n\n";
       body += "Request (semantically equivalent, slightly reformatted):\n\n";
       body += metadata.method + " " + metadata.path;
 
       if (metadata.queryString)
         body +=  "?" + metadata.queryString;
         
       body += " HTTP/" + metadata.httpVersion + "\r\n";
 
       var headEnum = metadata.headers;
       while (headEnum.hasMoreElements())
       {
         var fieldName = headEnum.getNext()
                                 .QueryInterface(Ci.nsISupportsString)
                                 .data;
         body += fieldName + ": " + metadata.getHeader(fieldName) + "\r\n";
       }
 
       response.bodyOutputStream.write(body, body.length);
     }
   }
 };
 
 
 /**
  * Maps absolute paths to files on the local file system (as nsILocalFiles).
  */
 function FileMap()
 {
   /** Hash which will map paths to nsILocalFiles. */
   this._map = {};
 }
 FileMap.prototype =
 {
   // PUBLIC API
 
   /**
    * Maps key to a clone of the nsILocalFile value if value is non-null;
    * otherwise, removes any extant mapping for key.
    *
    * @param key : string
    *   string to which a clone of value is mapped
    * @param value : nsILocalFile
    *   the file to map to key, or null to remove a mapping
    */
   put: function(key, value)
   {
     if (value)
       this._map[key] = value.clone();
     else
       delete this._map[key];
   },
 
   /**
    * Returns a clone of the nsILocalFile mapped to key, or null if no such
    * mapping exists.
    *
    * @param key : string
    *   key to which the returned file maps
    * @returns nsILocalFile
    *   a clone of the mapped file, or null if no mapping exists
    */
   get: function(key)
   {
     var val = this._map[key];
     return val ? val.clone() : null;
   }
 };
 
 
 // Response CONSTANTS
 
 // token       = *<any CHAR except CTLs or separators>
 // CHAR        = <any US-ASCII character (0-127)>
 // CTL         = <any US-ASCII control character (0-31) and DEL (127)>
 // separators  = "(" | ")" | "<" | ">" | "@"
 //             | "," | ";" | ":" | "\" | <">
 //             | "/" | "[" | "]" | "?" | "="
 //             | "{" | "}" | SP  | HT
 const IS_TOKEN_ARRAY =
   [0, 0, 0, 0, 0, 0, 0, 0, //   0
    0, 0, 0, 0, 0, 0, 0, 0, //   8
    0, 0, 0, 0, 0, 0, 0, 0, //  16
    0, 0, 0, 0, 0, 0, 0, 0, //  24
 
    0, 1, 0, 1, 1, 1, 1, 1, //  32
    0, 0, 1, 1, 0, 1, 1, 0, //  40
    1, 1, 1, 1, 1, 1, 1, 1, //  48
    1, 1, 0, 0, 0, 0, 0, 0, //  56
 
    0, 1, 1, 1, 1, 1, 1, 1, //  64
    1, 1, 1, 1, 1, 1, 1, 1, //  72
    1, 1, 1, 1, 1, 1, 1, 1, //  80
    1, 1, 1, 0, 0, 0, 1, 1, //  88
 
    1, 1, 1, 1, 1, 1, 1, 1, //  96
    1, 1, 1, 1, 1, 1, 1, 1, // 104
    1, 1, 1, 1, 1, 1, 1, 1, // 112
    1, 1, 1, 0, 1, 0, 1];   // 120
 
 
 /**
  * Determines whether the given character code is a CTL.
  *
  * @param code : uint
  *   the character code
  * @returns boolean
  *   true if code is a CTL, false otherwise
  */
 function isCTL(code)
 {
   return (code >= 0 && code <= 31) || (code == 127);
 }
 
 /**
  * Represents a response to an HTTP request, encapsulating all details of that
  * response.  This includes all headers, the HTTP version, status code and
  * explanation, and the entity itself.
  *
  * @param connection : Connection
  *   the connection over which this response is to be written
  */
 function Response(connection)
 {
   /** The connection over which this response will be written. */
   this._connection = connection;
 
   /**
    * The HTTP version of this response; defaults to 1.1 if not set by the
    * handler.
    */
   this._httpVersion = nsHttpVersion.HTTP_1_1;
 
   /**
    * The HTTP code of this response; defaults to 200.
    */
   this._httpCode = 200;
 
   /**
    * The description of the HTTP code in this response; defaults to "OK".
    */
   this._httpDescription = "OK";
 
   /**
    * An nsIHttpHeaders object in which the headers in this response should be
    * stored.  This property is null after the status line and headers have been
    * written to the network, and it may be modified up until it is cleared,
    * except if this._finished is set first (in which case headers are written
    * asynchronously in response to a finish() call not preceded by
    * flushHeaders()).
    */
   this._headers = new nsHttpHeaders();
 
   /**
    * Set to true when this response is ended (completely constructed if possible
    * and the connection closed); further actions on this will then fail.
    */
   this._ended = false;
 
   /**
    * A stream used to hold data written to the body of this response.
    */
   this._bodyOutputStream = null;
 
   /**
    * A stream containing all data that has been written to the body of this
    * response so far.  (Async handlers make the data contained in this
    * unreliable as a way of determining content length in general, but auxiliary
    * saved information can sometimes be used to guarantee reliability.)
    */
   this._bodyInputStream = null;
 
   /**
    * A stream copier which copies data to the network.  It is initially null
    * until replaced with a copier for response headers; when headers have been
    * fully sent it is replaced with a copier for the response body, remaining
    * so for the duration of response processing.
    */
   this._asyncCopier = null;
 
   /**
    * True if this response has been designated as being processed
    * asynchronously rather than for the duration of a single call to
    * nsIHttpRequestHandler.handle.
    */
   this._processAsync = false;
 
   /**
    * True iff finish() has been called on this, signaling that no more changes
    * to this may be made.
    */
   this._finished = false;
 
   /**
    * True iff powerSeized() has been called on this, signaling that this
    * response is to be handled manually by the response handler (which may then
    * send arbitrary data in response, even non-HTTP responses).
    */
   this._powerSeized = false;
 }
 Response.prototype =
 {
   // PUBLIC CONSTRUCTION API
 
   //
   // see nsIHttpResponse.bodyOutputStream
   //
   get bodyOutputStream()
   {
     if (this._finished)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
 
     if (!this._bodyOutputStream)
     {
       var pipe = new Pipe(true, false, Response.SEGMENT_SIZE, PR_UINT32_MAX,
                           null);
       this._bodyOutputStream = pipe.outputStream;
       this._bodyInputStream = pipe.inputStream;
       if (this._processAsync || this._powerSeized)
         this._startAsyncProcessor();
     }
 
     return this._bodyOutputStream;
   },
 
   //
   // see nsIHttpResponse.write
   //
   write: function(data)
   {
     if (this._finished)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
 
     var dataAsString = String(data);
     this.bodyOutputStream.write(dataAsString, dataAsString.length);
   },
 
   //
   // see nsIHttpResponse.setStatusLine
   //
   setStatusLine: function(httpVersion, code, description)
   {
     if (!this._headers || this._finished || this._powerSeized)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     this._ensureAlive();
 
     if (!(code >= 0 && code < 1000))
       throw Cr.NS_ERROR_INVALID_ARG;
 
     try
     {
       var httpVer;
       // avoid version construction for the most common cases
       if (!httpVersion || httpVersion == "1.1")
         httpVer = nsHttpVersion.HTTP_1_1;
       else if (httpVersion == "1.0")
         httpVer = nsHttpVersion.HTTP_1_0;
       else
         httpVer = new nsHttpVersion(httpVersion);
     }
     catch (e)
     {
       throw Cr.NS_ERROR_INVALID_ARG;
     }
 
     // Reason-Phrase = *<TEXT, excluding CR, LF>
     // TEXT          = <any OCTET except CTLs, but including LWS>
     //
     // XXX this ends up disallowing octets which aren't Unicode, I think -- not
     //     much to do if description is IDL'd as string
     if (!description)
       description = "";
     for (var i = 0; i < description.length; i++)
       if (isCTL(description.charCodeAt(i)) && description.charAt(i) != "\t")
         throw Cr.NS_ERROR_INVALID_ARG;
 
     // set the values only after validation to preserve atomicity
     this._httpDescription = description;
     this._httpCode = code;
     this._httpVersion = httpVer;
   },
 
   //
   // see nsIHttpResponse.setHeader
   //
   setHeader: function(name, value, merge)
   {
     if (!this._headers || this._finished || this._powerSeized)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     this._ensureAlive();
 
     this._headers.setHeader(name, value, merge);
   },
 
   //
   // see nsIHttpResponse.processAsync
   //
   processAsync: function()
   {
     if (this._finished)
       throw Cr.NS_ERROR_UNEXPECTED;
     if (this._powerSeized)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     if (this._processAsync)
       return;
     this._ensureAlive();
 
     dumpn("*** processing connection " + this._connection.number + " async");
     this._processAsync = true;
 
     /*
      * Either the bodyOutputStream getter or this method is responsible for
      * starting the asynchronous processor and catching writes of data to the
      * response body of async responses as they happen, for the purpose of
      * forwarding those writes to the actual connection's output stream.
      * If bodyOutputStream is accessed first, calling this method will create
      * the processor (when it first is clear that body data is to be written
      * immediately, not buffered).  If this method is called first, accessing
      * bodyOutputStream will create the processor.  If only this method is
      * called, we'll write nothing, neither headers nor the nonexistent body,
      * until finish() is called.  Since that delay is easily avoided by simply
      * getting bodyOutputStream or calling write(""), we don't worry about it.
      */
     if (this._bodyOutputStream && !this._asyncCopier)
       this._startAsyncProcessor();
   },
 
   //
   // see nsIHttpResponse.seizePower
   //
   seizePower: function()
   {
     if (this._processAsync)
       throw Cr.NS_ERROR_NOT_AVAILABLE;
     if (this._finished)
       throw Cr.NS_ERROR_UNEXPECTED;
     if (this._powerSeized)
       return;
     this._ensureAlive();
 
     dumpn("*** forcefully seizing power over connection " +
           this._connection.number + "...");
 
     // Purge any already-written data without sending it.  We could as easily
     // swap out the streams entirely, but that makes it possible to acquire and
     // unknowingly use a stale reference, so we require there only be one of
     // each stream ever for any response to avoid this complication.
     if (this._asyncCopier)
       this._asyncCopier.cancel(Cr.NS_BINDING_ABORTED);
     this._asyncCopier = null;
     if (this._bodyOutputStream)
     {
       var input = new BinaryInputStream(this._bodyInputStream);
       var avail;
       while ((avail = input.available()) > 0)
         input.readByteArray(avail);
     }
 
     this._powerSeized = true;
     if (this._bodyOutputStream)
       this._startAsyncProcessor();
   },
 
   //
   // see nsIHttpResponse.finish
   //
   finish: function()
   {
     if (!this._processAsync && !this._powerSeized)
       throw Cr.NS_ERROR_UNEXPECTED;
     if (this._finished)
       return;
 
     dumpn("*** finishing connection " + this._connection.number);
     this._startAsyncProcessor(); // in case bodyOutputStream was never accessed
     if (this._bodyOutputStream)
       this._bodyOutputStream.close();
     this._finished = true;
   },
 
 
   // NSISUPPORTS
 
   //
   // see nsISupports.QueryInterface
   //
   QueryInterface: function(iid)
   {
     if (iid.equals(Ci.nsIHttpResponse) || iid.equals(Ci.nsISupports))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // POST-CONSTRUCTION API (not exposed externally)
 
   /**
    * The HTTP version number of this, as a string (e.g. "1.1").
    */
   get httpVersion()
   {
     this._ensureAlive();
     return this._httpVersion.toString();
   },
 
   /**
    * The HTTP status code of this response, as a string of three characters per
    * RFC 2616.
    */
   get httpCode()
   {
     this._ensureAlive();
 
     var codeString = (this._httpCode < 10 ? "0" : "") +
                      (this._httpCode < 100 ? "0" : "") +
                      this._httpCode;
     return codeString;
   },
 
   /**
    * The description of the HTTP status code of this response, or "" if none is
    * set.
    */
   get httpDescription()
   {
     this._ensureAlive();
 
     return this._httpDescription;
   },
 
   /**
    * The headers in this response, as an nsHttpHeaders object.
    */
   get headers()
   {
     this._ensureAlive();
 
     return this._headers;
   },
 
   //
   // see nsHttpHeaders.getHeader
   //
   getHeader: function(name)
   {
     this._ensureAlive();
 
     return this._headers.getHeader(name);
   },
 
   /**
    * Determines whether this response may be abandoned in favor of a newly
    * constructed response.  A response may be abandoned only if it is not being
    * sent asynchronously and if raw control over it has not been taken from the
    * server.
    *
    * @returns boolean
    *   true iff no data has been written to the network
    */
   partiallySent: function()
   {
     dumpn("*** partiallySent()");
     return this._processAsync || this._powerSeized;
   },
 
   /**
    * If necessary, kicks off the remaining request processing needed to be done
    * after a request handler performs its initial work upon this response.
    */
   complete: function()
   {
     dumpn("*** complete()");
     if (this._processAsync || this._powerSeized)
     {
       NS_ASSERT(this._processAsync ^ this._powerSeized,
                 "can't both send async and relinquish power");
       return;
     }
 
     NS_ASSERT(!this.partiallySent(), "completing a partially-sent response?");
 
     this._startAsyncProcessor();
 
     // Now make sure we finish processing this request!
     if (this._bodyOutputStream)
       this._bodyOutputStream.close();
   },
 
   /**
    * Abruptly ends processing of this response, usually due to an error in an
    * incoming request but potentially due to a bad error handler.  Since we
    * cannot handle the error in the usual way (giving an HTTP error page in
    * response) because data may already have been sent (or because the response
    * might be expected to have been generated asynchronously or completely from
    * scratch by the handler), we stop processing this response and abruptly
    * close the connection.
    *
    * @param e : Error
    *   the exception which precipitated this abort, or null if no such exception
    *   was generated
    */
   abort: function(e)
   {
     dumpn("*** abort(<" + e + ">)");
 
     // This response will be ended by the processor if one was created.
     var copier = this._asyncCopier;
     if (copier)
     {
       // We dispatch asynchronously here so that any pending writes of data to
       // the connection will be deterministically written.  This makes it easier
       // to specify exact behavior, and it makes observable behavior more
       // predictable for clients.  Note that the correctness of this depends on
       // callbacks in response to _waitToReadData in WriteThroughCopier
       // happening asynchronously with respect to the actual writing of data to
       // bodyOutputStream, as they currently do; if they happened synchronously,
       // an event which ran before this one could write more data to the
       // response body before we get around to canceling the copier.  We have
       // tests for this in test_seizepower.js, however, and I can't think of a
       // way to handle both cases without removing bodyOutputStream access and
       // moving its effective write(data, length) method onto Response, which
       // would be slower and require more code than this anyway.
       gThreadManager.currentThread.dispatch({
         run: function()
         {
           dumpn("*** canceling copy asynchronously...");
           copier.cancel(Cr.NS_ERROR_UNEXPECTED);
         }
       }, Ci.nsIThread.DISPATCH_NORMAL);
     }
     else
     {
       this.end();
     }
   },
 
   /**
    * Closes this response's network connection, marks the response as finished,
    * and notifies the server handler that the request is done being processed.
    */
   end: function()
   {
     NS_ASSERT(!this._ended, "ending this response twice?!?!");
 
     this._connection.close();
     if (this._bodyOutputStream)
       this._bodyOutputStream.close();
 
     this._finished = true;
     this._ended = true;
   },
 
   // PRIVATE IMPLEMENTATION
 
   /**
    * Sends the status line and headers of this response if they haven't been
    * sent and initiates the process of copying data written to this response's
    * body to the network.
    */
   _startAsyncProcessor: function()
   {
     dumpn("*** _startAsyncProcessor()");
 
     // Handle cases where we're being called a second time.  The former case
     // happens when this is triggered both by complete() and by processAsync(),
     // while the latter happens when processAsync() in conjunction with sent
     // data causes abort() to be called.
     if (this._asyncCopier || this._ended)
     {
       dumpn("*** ignoring second call to _startAsyncProcessor");
       return;
     }
 
     // Send headers if they haven't been sent already and should be sent, then
     // asynchronously continue to send the body.
     if (this._headers && !this._powerSeized)
     {
       this._sendHeaders();
       return;
     }
 
     this._headers = null;
     this._sendBody();
   },
 
   /**
    * Signals that all modifications to the response status line and headers are
    * complete and then sends that data over the network to the client.  Once
    * this method completes, a different response to the request that resulted
    * in this response cannot be sent -- the only possible action in case of
    * error is to abort the response and close the connection.
    */
   _sendHeaders: function()
   {
     dumpn("*** _sendHeaders()");
 
     NS_ASSERT(this._headers);
     NS_ASSERT(!this._powerSeized);
 
     // request-line
     var statusLine = "HTTP/" + this.httpVersion + " " +
                      this.httpCode + " " +
                      this.httpDescription + "\r\n";
 
     // header post-processing
 
     var headers = this._headers;
     headers.setHeader("Connection", "close", false);
     headers.setHeader("Server", "httpd.js", false);
     if (!headers.hasHeader("Date"))
       headers.setHeader("Date", toDateString(Date.now()), false);
 
     // Any response not being processed asynchronously must have an associated
     // Content-Length header for reasons of backwards compatibility with the
     // initial server, which fully buffered every response before sending it.
     // Beyond that, however, it's good to do this anyway because otherwise it's
     // impossible to test behaviors that depend on the presence or absence of a
     // Content-Length header.
     if (!this._processAsync)
     {
       dumpn("*** non-async response, set Content-Length");
 
       var bodyStream = this._bodyInputStream;
       var avail = bodyStream ? bodyStream.available() : 0;
 
       // XXX assumes stream will always report the full amount of data available
       headers.setHeader("Content-Length", "" + avail, false);
     }
 
 
     // construct and send response
     dumpn("*** header post-processing completed, sending response head...");
 
     // request-line
     var preambleData = [statusLine];
 
     // headers
     var headEnum = headers.enumerator;
     while (headEnum.hasMoreElements())
     {
       var fieldName = headEnum.getNext()
                               .QueryInterface(Ci.nsISupportsString)
                               .data;
       var values = headers.getHeaderValues(fieldName);
       for (var i = 0, sz = values.length; i < sz; i++)
         preambleData.push(fieldName + ": " + values[i] + "\r\n");
     }
 
     // end request-line/headers
     preambleData.push("\r\n");
 
     var preamble = preambleData.join("");
 
     var responseHeadPipe = new Pipe(true, false, 0, PR_UINT32_MAX, null);
     responseHeadPipe.outputStream.write(preamble, preamble.length);
 
     var response = this;
     var copyObserver =
       {
         onStartRequest: function(request, cx)
         {
           dumpn("*** preamble copying started");
         },
 
         onStopRequest: function(request, cx, statusCode)
         {
           dumpn("*** preamble copying complete " +
                 "[status=0x" + statusCode.toString(16) + "]");
 
           if (!Components.isSuccessCode(statusCode))
           {
             dumpn("!!! header copying problems: non-success statusCode, " +
                   "ending response");
 
             response.end();
           }
           else
           {
             response._sendBody();
           }
         },
 
         QueryInterface: function(aIID)
         {
           if (aIID.equals(Ci.nsIRequestObserver) || aIID.equals(Ci.nsISupports))
             return this;
 
           throw Cr.NS_ERROR_NO_INTERFACE;
         }
       };
 
     var headerCopier = this._asyncCopier =
       new WriteThroughCopier(responseHeadPipe.inputStream,
                              this._connection.output,
                              copyObserver, null);
 
     responseHeadPipe.outputStream.close();
 
     // Forbid setting any more headers or modifying the request line.
     this._headers = null;
   },
 
   /**
    * Asynchronously writes the body of the response (or the entire response, if
    * seizePower() has been called) to the network.
    */
   _sendBody: function()
   {
     dumpn("*** _sendBody");
 
     NS_ASSERT(!this._headers, "still have headers around but sending body?");
 
     // If no body data was written, we're done
     if (!this._bodyInputStream)
     {
       dumpn("*** empty body, response finished");
       this.end();
       return;
     }
 
     var response = this;
     var copyObserver =
       {
         onStartRequest: function(request, context)
         {
           dumpn("*** onStartRequest");
         },
 
         onStopRequest: function(request, cx, statusCode)
         {
           dumpn("*** onStopRequest [status=0x" + statusCode.toString(16) + "]");
 
           if (statusCode === Cr.NS_BINDING_ABORTED)
           {
             dumpn("*** terminating copy observer without ending the response");
           }
           else
           {
             if (!Components.isSuccessCode(statusCode))
               dumpn("*** WARNING: non-success statusCode in onStopRequest");
 
             response.end();
           }
         },
 
         QueryInterface: function(aIID)
         {
           if (aIID.equals(Ci.nsIRequestObserver) || aIID.equals(Ci.nsISupports))
             return this;
 
           throw Cr.NS_ERROR_NO_INTERFACE;
         }
       };
 
     dumpn("*** starting async copier of body data...");
     this._asyncCopier =
       new WriteThroughCopier(this._bodyInputStream, this._connection.output,
                             copyObserver, null);
   },
 
   /** Ensures that this hasn't been ended. */
   _ensureAlive: function()
   {
     NS_ASSERT(!this._ended, "not handling response lifetime correctly");
   }
 };
 
 /**
  * Size of the segments in the buffer used in storing response data and writing
  * it to the socket.
  */
 Response.SEGMENT_SIZE = 8192;
 
 /** Serves double duty in WriteThroughCopier implementation. */
 function notImplemented()
 {
   throw Cr.NS_ERROR_NOT_IMPLEMENTED;
 }
 
 /** Returns true iff the given exception represents stream closure. */
 function streamClosed(e)
 {
   return e === Cr.NS_BASE_STREAM_CLOSED ||
          (typeof e === "object" && e.result === Cr.NS_BASE_STREAM_CLOSED);
 }
 
 /** Returns true iff the given exception represents a blocked stream. */
 function wouldBlock(e)
 {
   return e === Cr.NS_BASE_STREAM_WOULD_BLOCK ||
          (typeof e === "object" && e.result === Cr.NS_BASE_STREAM_WOULD_BLOCK);
 }
 
 /**
  * Copies data from source to sink as it becomes available, when that data can
  * be written to sink without blocking.
  *
  * @param source : nsIAsyncInputStream
  *   the stream from which data is to be read
  * @param sink : nsIAsyncOutputStream
  *   the stream to which data is to be copied
  * @param observer : nsIRequestObserver
  *   an observer which will be notified when the copy starts and finishes
  * @param context : nsISupports
  *   context passed to observer when notified of start/stop
  * @throws NS_ERROR_NULL_POINTER
  *   if source, sink, or observer are null
  */
 function WriteThroughCopier(source, sink, observer, context)
 {
   if (!source || !sink || !observer)
     throw Cr.NS_ERROR_NULL_POINTER;
 
   /** Stream from which data is being read. */
   this._source = source;
 
   /** Stream to which data is being written. */
   this._sink = sink;
 
   /** Observer watching this copy. */
   this._observer = observer;
 
   /** Context for the observer watching this. */
   this._context = context;
 
   /**
    * True iff this is currently being canceled (cancel has been called, the
    * callback may not yet have been made).
    */
   this._canceled = false;
 
   /**
    * False until all data has been read from input and written to output, at
    * which point this copy is completed and cancel() is asynchronously called.
    */
   this._completed = false;
 
   /** Required by nsIRequest, meaningless. */
   this.loadFlags = 0;
   /** Required by nsIRequest, meaningless. */
   this.loadGroup = null;
   /** Required by nsIRequest, meaningless. */
   this.name = "response-body-copy";
 
   /** Status of this request. */
   this.status = Cr.NS_OK;
 
   /** Arrays of byte strings waiting to be written to output. */
   this._pendingData = [];
 
   // start copying
   try
   {
     observer.onStartRequest(this, context);
     this._waitToReadData();
     this._waitForSinkClosure();
   }
   catch (e)
   {
     dumpn("!!! error starting copy: " + e +
           ("lineNumber" in e ? ", line " + e.lineNumber : ""));
     dumpn(e.stack);
     this.cancel(Cr.NS_ERROR_UNEXPECTED);
   }
 }
 WriteThroughCopier.prototype =
 {
   /* nsISupports implementation */
 
   QueryInterface: function(iid)
   {
     if (iid.equals(Ci.nsIInputStreamCallback) ||
         iid.equals(Ci.nsIOutputStreamCallback) ||
         iid.equals(Ci.nsIRequest) ||
         iid.equals(Ci.nsISupports))
     {
       return this;
     }
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // NSIINPUTSTREAMCALLBACK
 
   /**
    * Receives a more-data-in-input notification and writes the corresponding
    * data to the output.
    *
    * @param input : nsIAsyncInputStream
    *   the input stream on whose data we have been waiting
    */
   onInputStreamReady: function(input)
   {
     if (this._source === null)
       return;
 
     dumpn("*** onInputStreamReady");
 
     //
     // Ordinarily we'll read a non-zero amount of data from input, queue it up
     // to be written and then wait for further callbacks.  The complications in
     // this method are the cases where we deviate from that behavior when errors
     // occur or when copying is drawing to a finish.
     //
     // The edge cases when reading data are:
     //
     //   Zero data is read
     //     If zero data was read, we're at the end of available data, so we can
     //     should stop reading and move on to writing out what we have (or, if
     //     we've already done that, onto notifying of completion).
     //   A stream-closed exception is thrown
     //     This is effectively a less kind version of zero data being read; the
     //     only difference is that we notify of completion with that result
     //     rather than with NS_OK.
     //   Some other exception is thrown
     //     This is the least kind result.  We don't know what happened, so we
     //     act as though the stream closed except that we notify of completion
     //     with the result NS_ERROR_UNEXPECTED.
     //
 
     var bytesWanted = 0, bytesConsumed = -1;
     try
     {
       input = new BinaryInputStream(input);
 
       bytesWanted = Math.min(input.available(), Response.SEGMENT_SIZE);
       dumpn("*** input wanted: " + bytesWanted);
 
       if (bytesWanted > 0)
       {
         var data = input.readByteArray(bytesWanted);
         bytesConsumed = data.length;
         this._pendingData.push(String.fromCharCode.apply(String, data));
       }
 
       dumpn("*** " + bytesConsumed + " bytes read");
 
       // Handle the zero-data edge case in the same place as all other edge
       // cases are handled.
       if (bytesWanted === 0)
         throw Cr.NS_BASE_STREAM_CLOSED;
     }
     catch (e)
     {
       if (streamClosed(e))
       {
         dumpn("*** input stream closed");
         e = bytesWanted === 0 ? Cr.NS_OK : Cr.NS_ERROR_UNEXPECTED;
       }
       else
       {
         dumpn("!!! unexpected error reading from input, canceling: " + e);
         e = Cr.NS_ERROR_UNEXPECTED;
       }
 
       this._doneReadingSource(e);
       return;
     }
 
     var pendingData = this._pendingData;
 
     NS_ASSERT(bytesConsumed > 0);
     NS_ASSERT(pendingData.length > 0, "no pending data somehow?");
     NS_ASSERT(pendingData[pendingData.length - 1].length > 0,
               "buffered zero bytes of data?");
 
     NS_ASSERT(this._source !== null);
 
     // Reading has gone great, and we've gotten data to write now.  What if we
     // don't have a place to write that data, because output went away just
     // before this read?  Drop everything on the floor, including new data, and
     // cancel at this point.
     if (this._sink === null)
     {
       pendingData.length = 0;
       this._doneReadingSource(Cr.NS_ERROR_UNEXPECTED);
       return;
     }
 
     // Okay, we've read the data, and we know we have a place to write it.  We
     // need to queue up the data to be written, but *only* if none is queued
     // already -- if data's already queued, the code that actually writes the
     // data will make sure to wait on unconsumed pending data.
     try
     {
       if (pendingData.length === 1)
         this._waitToWriteData();
     }
     catch (e)
     {
       dumpn("!!! error waiting to write data just read, swallowing and " +
             "writing only what we already have: " + e);
       this._doneWritingToSink(Cr.NS_ERROR_UNEXPECTED);
       return;
     }
 
     // Whee!  We successfully read some data, and it's successfully queued up to
     // be written.  All that remains now is to wait for more data to read.
     try
     {
       this._waitToReadData();
     }
     catch (e)
     {
       dumpn("!!! error waiting to read more data: " + e);
       this._doneReadingSource(Cr.NS_ERROR_UNEXPECTED);
     }
   },
 
 
   // NSIOUTPUTSTREAMCALLBACK
 
   /**
    * Callback when data may be written to the output stream without blocking, or
    * when the output stream has been closed.
    *
    * @param output : nsIAsyncOutputStream
    *   the output stream on whose writability we've been waiting, also known as
    *   this._sink
    */
   onOutputStreamReady: function(output)
   {
     if (this._sink === null)
       return;
 
     dumpn("*** onOutputStreamReady");
 
     var pendingData = this._pendingData;
     if (pendingData.length === 0)
     {
       // There's no pending data to write.  The only way this can happen is if
       // we're waiting on the output stream's closure, so we can respond to a
       // copying failure as quickly as possible (rather than waiting for data to
       // be available to read and then fail to be copied).  Therefore, we must
       // be done now -- don't bother to attempt to write anything and wrap
       // things up.
       dumpn("!!! output stream closed prematurely, ending copy");
 
       this._doneWritingToSink(Cr.NS_ERROR_UNEXPECTED);
       return;
     }
 
 
     NS_ASSERT(pendingData[0].length > 0, "queued up an empty quantum?");
 
     //
     // Write out the first pending quantum of data.  The possible errors here
     // are:
     //
     //   The write might fail because we can't write that much data
     //     Okay, we've written what we can now, so re-queue what's left and
     //     finish writing it out later.
     //   The write failed because the stream was closed
     //     Discard pending data that we can no longer write, stop reading, and
     //     signal that copying finished.
     //   Some other error occurred.
     //     Same as if the stream were closed, but notify with the status
     //     NS_ERROR_UNEXPECTED so the observer knows something was wonky.
     //
 
     try
     {
       var quantum = pendingData[0];
 
       // XXX |quantum| isn't guaranteed to be ASCII, so we're relying on
       //     undefined behavior!  We're only using this because writeByteArray
       //     is unusably broken for asynchronous output streams; see bug 532834
       //     for details.
       var bytesWritten = output.write(quantum, quantum.length);
       if (bytesWritten === quantum.length)
         pendingData.shift();
       else
         pendingData[0] = quantum.substring(bytesWritten);
 
       dumpn("*** wrote " + bytesWritten + " bytes of data");
     }
     catch (e)
     {
       if (wouldBlock(e))
       {
         NS_ASSERT(pendingData.length > 0,
                   "stream-blocking exception with no data to write?");
         NS_ASSERT(pendingData[0].length > 0,
                   "stream-blocking exception with empty quantum?");
         this._waitToWriteData();
         return;
       }
 
       if (streamClosed(e))
         dumpn("!!! output stream prematurely closed, signaling error...");
       else
         dumpn("!!! unknown error: " + e + ", quantum=" + quantum);
 
       this._doneWritingToSink(Cr.NS_ERROR_UNEXPECTED);
       return;
     }
 
     // The day is ours!  Quantum written, now let's see if we have more data
     // still to write.
     try
     {
       if (pendingData.length > 0)
       {
         this._waitToWriteData();
         return;
       }
     }
     catch (e)
     {
       dumpn("!!! unexpected error waiting to write pending data: " + e);
       this._doneWritingToSink(Cr.NS_ERROR_UNEXPECTED);
       return;
     }
 
     // Okay, we have no more pending data to write -- but might we get more in
     // the future?
     if (this._source !== null)
     {
       /*
        * If we might, then wait for the output stream to be closed.  (We wait
        * only for closure because we have no data to write -- and if we waited
        * for a specific amount of data, we would get repeatedly notified for no
        * reason if over time the output stream permitted more and more data to
        * be written to it without blocking.)
        */
        this._waitForSinkClosure();
     }
     else
     {
       /*
        * On the other hand, if we can't have more data because the input
        * stream's gone away, then it's time to notify of copy completion.
        * Victory!
        */
       this._sink = null;
       this._cancelOrDispatchCancelCallback(Cr.NS_OK);
     }
   },
 
 
   // NSIREQUEST
 
   /** Returns true if the cancel observer hasn't been notified yet. */
   isPending: function()
   {
     return !this._completed;
   },
 
   /** Not implemented, don't use! */
   suspend: notImplemented,
   /** Not implemented, don't use! */
   resume: notImplemented,
 
   /**
    * Cancels data reading from input, asynchronously writes out any pending
    * data, and causes the observer to be notified with the given error code when
    * all writing has finished.
    *
    * @param status : nsresult
    *   the status to pass to the observer when data copying has been canceled
    */
   cancel: function(status)
   {
     dumpn("*** cancel(" + status.toString(16) + ")");
 
     if (this._canceled)
     {
       dumpn("*** suppressing a late cancel");
       return;
     }
 
     this._canceled = true;
     this.status = status;
 
     // We could be in the middle of absolutely anything at this point.  Both
     // input and output might still be around, we might have pending data to
     // write, and in general we know nothing about the state of the world.  We
     // therefore must assume everything's in progress and take everything to its
     // final steady state (or so far as it can go before we need to finish
     // writing out remaining data).
 
     this._doneReadingSource(status);
   },
 
 
   // PRIVATE IMPLEMENTATION
 
   /**
    * Stop reading input if we haven't already done so, passing e as the status
    * when closing the stream, and kick off a copy-completion notice if no more
    * data remains to be written.
    *
    * @param e : nsresult
    *   the status to be used when closing the input stream
    */
   _doneReadingSource: function(e)
   {
     dumpn("*** _doneReadingSource(0x" + e.toString(16) + ")");
 
     this._finishSource(e);
     if (this._pendingData.length === 0)
       this._sink = null;
     else
       NS_ASSERT(this._sink !== null, "null output?");
 
     // If we've written out all data read up to this point, then it's time to
     // signal completion.
     if (this._sink === null)
     {
       NS_ASSERT(this._pendingData.length === 0, "pending data still?");
       this._cancelOrDispatchCancelCallback(e);
     }
   },
 
   /**
    * Stop writing output if we haven't already done so, discard any data that
    * remained to be sent, close off input if it wasn't already closed, and kick
    * off a copy-completion notice.
    *
    * @param e : nsresult
    *   the status to be used when closing input if it wasn't already closed
    */
   _doneWritingToSink: function(e)
   {
     dumpn("*** _doneWritingToSink(0x" + e.toString(16) + ")");
 
     this._pendingData.length = 0;
     this._sink = null;
     this._doneReadingSource(e);
   },
 
   /**
    * Completes processing of this copy: either by canceling the copy if it
    * hasn't already been canceled using the provided status, or by dispatching
    * the cancel callback event (with the originally provided status, of course)
    * if it already has been canceled.
    *
    * @param status : nsresult
    *   the status code to use to cancel this, if this hasn't already been
    *   canceled
    */
   _cancelOrDispatchCancelCallback: function(status)
   {
     dumpn("*** _cancelOrDispatchCancelCallback(" + status + ")");
 
     NS_ASSERT(this._source === null, "should have finished input");
     NS_ASSERT(this._sink === null, "should have finished output");
     NS_ASSERT(this._pendingData.length === 0, "should have no pending data");
 
     if (!this._canceled)
     {
       this.cancel(status);
       return;
     }
 
     var self = this;
     var event =
       {
         run: function()
         {
           dumpn("*** onStopRequest async callback");
 
           self._completed = true;
           try
           {
             self._observer.onStopRequest(self, self._context, self.status);
           }
           catch (e)
           {
             NS_ASSERT(false,
                       "how are we throwing an exception here?  we control " +
                       "all the callers!  " + e);
           }
         }
       };
 
     gThreadManager.currentThread.dispatch(event, Ci.nsIThread.DISPATCH_NORMAL);
   },
 
   /**
    * Kicks off another wait for more data to be available from the input stream.
    */
   _waitToReadData: function()
   {
     dumpn("*** _waitToReadData");
     this._source.asyncWait(this, 0, Response.SEGMENT_SIZE,
                            gThreadManager.mainThread);
   },
 
   /**
    * Kicks off another wait until data can be written to the output stream.
    */
   _waitToWriteData: function()
   {
     dumpn("*** _waitToWriteData");
 
     var pendingData = this._pendingData;
     NS_ASSERT(pendingData.length > 0, "no pending data to write?");
     NS_ASSERT(pendingData[0].length > 0, "buffered an empty write?");
 
     this._sink.asyncWait(this, 0, pendingData[0].length,
                          gThreadManager.mainThread);
   },
 
   /**
    * Kicks off a wait for the sink to which data is being copied to be closed.
    * We wait for stream closure when we don't have any data to be copied, rather
    * than waiting to write a specific amount of data.  We can't wait to write
    * data because the sink might be infinitely writable, and if no data appears
    * in the source for a long time we might have to spin quite a bit waiting to
    * write, waiting to write again, &c.  Waiting on stream closure instead means
    * we'll get just one notification if the sink dies.  Note that when data
    * starts arriving from the sink we'll resume waiting for data to be written,
    * dropping this closure-only callback entirely.
    */
   _waitForSinkClosure: function()
   {
     dumpn("*** _waitForSinkClosure");
 
     this._sink.asyncWait(this, Ci.nsIAsyncOutputStream.WAIT_CLOSURE_ONLY, 0,
                          gThreadManager.mainThread);
   },
 
   /**
    * Closes input with the given status, if it hasn't already been closed;
    * otherwise a no-op.
    *
    * @param status : nsresult
    *   status code use to close the source stream if necessary
    */
   _finishSource: function(status)
   {
     dumpn("*** _finishSource(" + status.toString(16) + ")");
 
     if (this._source !== null)
     {
       this._source.closeWithStatus(status);
       this._source = null;
     }
   }
 };
 
 
 /**
  * A container for utility functions used with HTTP headers.
  */
 const headerUtils =
 {
   /**
    * Normalizes fieldName (by converting it to lowercase) and ensures it is a
    * valid header field name (although not necessarily one specified in RFC
    * 2616).
    *
    * @throws NS_ERROR_INVALID_ARG
    *   if fieldName does not match the field-name production in RFC 2616
    * @returns string
    *   fieldName converted to lowercase if it is a valid header, for characters
    *   where case conversion is possible
    */
   normalizeFieldName: function(fieldName)
   {
     if (fieldName == "")
     {
       dumpn("*** Empty fieldName");
       throw Cr.NS_ERROR_INVALID_ARG;
     }
 
     for (var i = 0, sz = fieldName.length; i < sz; i++)
     {
       if (!IS_TOKEN_ARRAY[fieldName.charCodeAt(i)])
       {
         dumpn(fieldName + " is not a valid header field name!");
         throw Cr.NS_ERROR_INVALID_ARG;
       }
     }
 
     return fieldName.toLowerCase();
   },
 
   /**
    * Ensures that fieldValue is a valid header field value (although not
    * necessarily as specified in RFC 2616 if the corresponding field name is
    * part of the HTTP protocol), normalizes the value if it is, and
    * returns the normalized value.
    *
    * @param fieldValue : string
    *   a value to be normalized as an HTTP header field value
    * @throws NS_ERROR_INVALID_ARG
    *   if fieldValue does not match the field-value production in RFC 2616
    * @returns string
    *   fieldValue as a normalized HTTP header field value
    */
   normalizeFieldValue: function(fieldValue)
   {
     // field-value    = *( field-content | LWS )
     // field-content  = <the OCTETs making up the field-value
     //                  and consisting of either *TEXT or combinations
     //                  of token, separators, and quoted-string>
     // TEXT           = <any OCTET except CTLs,
     //                  but including LWS>
     // LWS            = [CRLF] 1*( SP | HT )
     //
     // quoted-string  = ( <"> *(qdtext | quoted-pair ) <"> )
     // qdtext         = <any TEXT except <">>
     // quoted-pair    = "\" CHAR
     // CHAR           = <any US-ASCII character (octets 0 - 127)>
 
     // Any LWS that occurs between field-content MAY be replaced with a single
     // SP before interpreting the field value or forwarding the message
     // downstream (section 4.2); we replace 1*LWS with a single SP
     var val = fieldValue.replace(/(?:(?:\r\n)?[ \t]+)+/g, " ");
 
     // remove leading/trailing LWS (which has been converted to SP)
     val = val.replace(/^ +/, "").replace(/ +$/, "");
 
     // that should have taken care of all CTLs, so val should contain no CTLs
     dumpn("*** Normalized value: '" + val + "'");
     for (var i = 0, len = val.length; i < len; i++)
       if (isCTL(val.charCodeAt(i)))
       {
         dump("*** Char " + i + " has charcode " + val.charCodeAt(i));
         throw Cr.NS_ERROR_INVALID_ARG;
       }
 
     // XXX disallows quoted-pair where CHAR is a CTL -- will not invalidly
     //     normalize, however, so this can be construed as a tightening of the
     //     spec and not entirely as a bug
     return val;
   }
 };
 
 
 
 /**
  * Converts the given string into a string which is safe for use in an HTML
  * context.
  *
  * @param str : string
  *   the string to make HTML-safe
  * @returns string
  *   an HTML-safe version of str
  */
 function htmlEscape(str)
 {
   // this is naive, but it'll work
   var s = "";
   for (var i = 0; i < str.length; i++)
     s += "&#" + str.charCodeAt(i) + ";";
   return s;
 }
 
 
 /**
  * Constructs an object representing an HTTP version (see section 3.1).
  *
  * @param versionString
  *   a string of the form "#.#", where # is an non-negative decimal integer with
  *   or without leading zeros
  * @throws
  *   if versionString does not specify a valid HTTP version number
  */
 function nsHttpVersion(versionString)
 {
   var matches = /^(\d+)\.(\d+)$/.exec(versionString);
   if (!matches)
     throw "Not a valid HTTP version!";
 
   /** The major version number of this, as a number. */
   this.major = parseInt(matches[1], 10);
 
   /** The minor version number of this, as a number. */
   this.minor = parseInt(matches[2], 10);
 
   if (isNaN(this.major) || isNaN(this.minor) ||
       this.major < 0    || this.minor < 0)
     throw "Not a valid HTTP version!";
 }
 nsHttpVersion.prototype =
 {
   /**
    * Returns the standard string representation of the HTTP version represented
    * by this (e.g., "1.1").
    */
   toString: function ()
   {
     return this.major + "." + this.minor;
   },
 
   /**
    * Returns true if this represents the same HTTP version as otherVersion,
    * false otherwise.
    *
    * @param otherVersion : nsHttpVersion
    *   the version to compare against this
    */
   equals: function (otherVersion)
   {
     return this.major == otherVersion.major &&
            this.minor == otherVersion.minor;
   },
 
   /** True if this >= otherVersion, false otherwise. */
   atLeast: function(otherVersion)
   {
     return this.major > otherVersion.major ||
            (this.major == otherVersion.major &&
             this.minor >= otherVersion.minor);
   }
 };
 
 nsHttpVersion.HTTP_1_0 = new nsHttpVersion("1.0");
 nsHttpVersion.HTTP_1_1 = new nsHttpVersion("1.1");
 
 
 /**
  * An object which stores HTTP headers for a request or response.
  *
  * Note that since headers are case-insensitive, this object converts headers to
  * lowercase before storing them.  This allows the getHeader and hasHeader
  * methods to work correctly for any case of a header, but it means that the
  * values returned by .enumerator may not be equal case-sensitively to the
  * values passed to setHeader when adding headers to this.
  */
 function nsHttpHeaders()
 {
   /**
    * A hash of headers, with header field names as the keys and header field
    * values as the values.  Header field names are case-insensitive, but upon
    * insertion here they are converted to lowercase.  Header field values are
    * normalized upon insertion to contain no leading or trailing whitespace.
    *
    * Note also that per RFC 2616, section 4.2, two headers with the same name in
    * a message may be treated as one header with the same field name and a field
    * value consisting of the separate field values joined together with a "," in
    * their original order.  This hash stores multiple headers with the same name
    * in this manner.
    */
   this._headers = {};
 }
 nsHttpHeaders.prototype =
 {
   /**
    * Sets the header represented by name and value in this.
    *
    * @param name : string
    *   the header name
    * @param value : string
    *   the header value
    * @throws NS_ERROR_INVALID_ARG
    *   if name or value is not a valid header component
    */
   setHeader: function(fieldName, fieldValue, merge)
   {
     var name = headerUtils.normalizeFieldName(fieldName);
     var value = headerUtils.normalizeFieldValue(fieldValue);
 
     // The following three headers are stored as arrays because their real-world
     // syntax prevents joining individual headers into a single header using 
     // ",".  See also <http://hg.mozilla.org/mozilla-central/diff/9b2a99adc05e/netwerk/protocol/http/src/nsHttpHeaderArray.cpp#l77>
     if (merge && name in this._headers)
     {
       if (name === "www-authenticate" ||
           name === "proxy-authenticate" ||
           name === "set-cookie") 
       {
         this._headers[name].push(value);
       }
       else 
       {
         this._headers[name][0] += "," + value;
         NS_ASSERT(this._headers[name].length === 1,
             "how'd a non-special header have multiple values?")
       }
     }
     else
     {
       this._headers[name] = [value];
     }
   },
 
   /**
    * Returns the value for the header specified by this.
    *
    * @throws NS_ERROR_INVALID_ARG
    *   if fieldName does not constitute a valid header field name
    * @throws NS_ERROR_NOT_AVAILABLE
    *   if the given header does not exist in this
    * @returns string
    *   the field value for the given header, possibly with non-semantic changes
    *   (i.e., leading/trailing whitespace stripped, whitespace runs replaced
    *   with spaces, etc.) at the option of the implementation; multiple 
    *   instances of the header will be combined with a comma, except for 
    *   the three headers noted in the description of getHeaderValues
    */
   getHeader: function(fieldName)
   {
     return this.getHeaderValues(fieldName).join("\n");
   },
 
   /**
    * Returns the value for the header specified by fieldName as an array.
    *
    * @throws NS_ERROR_INVALID_ARG
    *   if fieldName does not constitute a valid header field name
    * @throws NS_ERROR_NOT_AVAILABLE
    *   if the given header does not exist in this
    * @returns [string]
    *   an array of all the header values in this for the given
    *   header name.  Header values will generally be collapsed
    *   into a single header by joining all header values together
    *   with commas, but certain headers (Proxy-Authenticate,
    *   WWW-Authenticate, and Set-Cookie) violate the HTTP spec
    *   and cannot be collapsed in this manner.  For these headers
    *   only, the returned array may contain multiple elements if
    *   that header has been added more than once.
    */
   getHeaderValues: function(fieldName)
   {
     var name = headerUtils.normalizeFieldName(fieldName);
 
     if (name in this._headers)
       return this._headers[name];
     else
       throw Cr.NS_ERROR_NOT_AVAILABLE;
   },
 
   /**
    * Returns true if a header with the given field name exists in this, false
    * otherwise.
    *
    * @param fieldName : string
    *   the field name whose existence is to be determined in this
    * @throws NS_ERROR_INVALID_ARG
    *   if fieldName does not constitute a valid header field name
    * @returns boolean
    *   true if the header's present, false otherwise
    */
   hasHeader: function(fieldName)
   {
     var name = headerUtils.normalizeFieldName(fieldName);
     return (name in this._headers);
   },
 
   /**
    * Returns a new enumerator over the field names of the headers in this, as
    * nsISupportsStrings.  The names returned will be in lowercase, regardless of
    * how they were input using setHeader (header names are case-insensitive per
    * RFC 2616).
    */
   get enumerator()
   {
     var headers = [];
     for (var i in this._headers)
     {
       var supports = new SupportsString();
       supports.data = i;
       headers.push(supports);
     }
 
     return new nsSimpleEnumerator(headers);
   }
 };
 
 
 /**
  * Constructs an nsISimpleEnumerator for the given array of items.
  *
  * @param items : Array
  *   the items, which must all implement nsISupports
  */
 function nsSimpleEnumerator(items)
 {
   this._items = items;
   this._nextIndex = 0;
 }
 nsSimpleEnumerator.prototype =
 {
   hasMoreElements: function()
   {
     return this._nextIndex < this._items.length;
   },
   getNext: function()
   {
     if (!this.hasMoreElements())
       throw Cr.NS_ERROR_NOT_AVAILABLE;
 
     return this._items[this._nextIndex++];
   },
   QueryInterface: function(aIID)
   {
     if (Ci.nsISimpleEnumerator.equals(aIID) ||
         Ci.nsISupports.equals(aIID))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   }
 };
 
 
 /**
  * A representation of the data in an HTTP request.
  *
  * @param port : uint
  *   the port on which the server receiving this request runs
  */
 function Request(port)
 {
   /** Method of this request, e.g. GET or POST. */
   this._method = "";
 
   /** Path of the requested resource; empty paths are converted to '/'. */
   this._path = "";
 
   /** Query string, if any, associated with this request (not including '?'). */
   this._queryString = "";
 
   /** Scheme of requested resource, usually http, always lowercase. */
   this._scheme = "http";
 
   /** Hostname on which the requested resource resides. */
   this._host = undefined;
 
   /** Port number over which the request was received. */
   this._port = port;
 
   var bodyPipe = new Pipe(false, false, 0, PR_UINT32_MAX, null);
 
   /** Stream from which data in this request's body may be read. */
   this._bodyInputStream = bodyPipe.inputStream;
 
   /** Stream to which data in this request's body is written. */
   this._bodyOutputStream = bodyPipe.outputStream;
 
   /**
    * The headers in this request.
    */
   this._headers = new nsHttpHeaders();
 
   /**
    * For the addition of ad-hoc properties and new functionality without having
    * to change nsIHttpRequest every time; currently lazily created, as its only
    * use is in directory listings.
    */
   this._bag = null;
 }
 Request.prototype =
 {
   // SERVER METADATA
 
   //
   // see nsIHttpRequest.scheme
   //
   get scheme()
   {
     return this._scheme;
   },
 
   //
   // see nsIHttpRequest.host
   //
   get host()
   {
     return this._host;
   },
 
   //
   // see nsIHttpRequest.port
   //
   get port()
   {
     return this._port;
   },
 
   // REQUEST LINE
 
   //
   // see nsIHttpRequest.method
   //
   get method()
   {
     return this._method;
   },
 
   //
   // see nsIHttpRequest.httpVersion
   //
   get httpVersion()
   {
     return this._httpVersion.toString();
   },
 
   //
   // see nsIHttpRequest.path
   //
   get path()
   {
     return this._path;
   },
 
   //
   // see nsIHttpRequest.queryString
   //
   get queryString()
   {
     return this._queryString;
   },
 
   // HEADERS
 
   //
   // see nsIHttpRequest.getHeader
   //
   getHeader: function(name)
   {
     return this._headers.getHeader(name);
   },
 
   //
   // see nsIHttpRequest.hasHeader
   //
   hasHeader: function(name)
   {
     return this._headers.hasHeader(name);
   },
 
   //
   // see nsIHttpRequest.headers
   //
   get headers()
   {
     return this._headers.enumerator;
   },
 
   //
   // see nsIPropertyBag.enumerator
   //
   get enumerator()
   {
     this._ensurePropertyBag();
     return this._bag.enumerator;
   },
 
   //
   // see nsIHttpRequest.headers
   //
   get bodyInputStream()
   {
     return this._bodyInputStream;
   },
 
   //
   // see nsIPropertyBag.getProperty
   //
   getProperty: function(name) 
   {
     this._ensurePropertyBag();
     return this._bag.getProperty(name);
   },
 
 
   // NSISUPPORTS
 
   //
   // see nsISupports.QueryInterface
   //
   QueryInterface: function(iid)
   {
     if (iid.equals(Ci.nsIHttpRequest) || iid.equals(Ci.nsISupports))
       return this;
 
     throw Cr.NS_ERROR_NO_INTERFACE;
   },
 
 
   // PRIVATE IMPLEMENTATION
   
   /** Ensures a property bag has been created for ad-hoc behaviors. */
   _ensurePropertyBag: function()
   {
     if (!this._bag)
       this._bag = new WritablePropertyBag();
   }
 };
 
 
 // XPCOM trappings
 
 this.NSGetFactory = XPCOMUtils.generateNSGetFactory([nsHttpServer]);
 
 /**
  * Creates a new HTTP server listening for loopback traffic on the given port,
  * starts it, and runs the server until the server processes a shutdown request,
  * spinning an event loop so that events posted by the server's socket are
  * processed.
  *
  * This method is primarily intended for use in running this script from within
  * xpcshell and running a functional HTTP server without having to deal with
  * non-essential details.
  *
  * Note that running multiple servers using variants of this method probably
  * doesn't work, simply due to how the internal event loop is spun and stopped.
  *
  * @note
  *   This method only works with Mozilla 1.9 (i.e., Firefox 3 or trunk code);
  *   you should use this server as a component in Mozilla 1.8.
  * @param port
  *   the port on which the server will run, or -1 if there exists no preference
  *   for a specific port; note that attempting to use some values for this
  *   parameter (particularly those below 1024) may cause this method to throw or
  *   may result in the server being prematurely shut down
  * @param basePath
  *   a local directory from which requests will be served (i.e., if this is
  *   "/home/jwalden/" then a request to /index.html will load
  *   /home/jwalden/index.html); if this is omitted, only the default URLs in
  *   this server implementation will be functional
  */
 function server(port, basePath)
 {
   if (basePath)
   {
     var lp = Cc["@mozilla.org/file/local;1"]
                .createInstance(Ci.nsILocalFile);
     lp.initWithPath(basePath);
   }
 
   // if you're running this, you probably want to see debugging info
   DEBUG = true;
 
   var srv = new nsHttpServer();
   if (lp)
     srv.registerDirectory("/", lp);
   srv.registerContentType("sjs", SJS_TYPE);
   srv.identity.setPrimary("http", "localhost", port);
   srv.start(port);
 
   var thread = gThreadManager.currentThread;
   while (!srv.isStopped())
     thread.processNextEvent(true);
 
   // get rid of any pending requests
   while (thread.hasPendingEvents())
     thread.processNextEvent(true);
 
   DEBUG = false;
 }