Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 5576 insertions, 0 deletions

diff --git a/netwerk/test/httpserver/httpd.sys.mjs b/netwerk/test/httpserver/httpd.sys.mjs
new file mode 100644
index 0000000000..569e4d1489
--- /dev/null
+++ b/netwerk/test/httpserver/httpd.sys.mjs
@@ -0,0 +1,5576 @@
+/* -*- 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.
+ */
+
+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
+
+/**
+ * Sets the debugging status, intended for tweaking in server tests.
+ *
+ * @param {boolean} debug
+ *   Enables debugging output
+ * @param {boolean} debugTimestamp
+ *   Enables timestamping of the debugging output.
+ */
+export function setDebuggingStatus(debug, debugTimestamp) {
+  DEBUG = debug;
+  DEBUG_TIMESTAMP = debugTimestamp;
+}
+
+import { AppConstants } from "resource://gre/modules/AppConstants.sys.mjs";
+
+/**
+ * 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 Components.Exception("", Cr.NS_ERROR_ABORT);
+  }
+}
+
+/** Constructs an HTTP error object. */
+export function HttpError(code, description) {
+  this.code = code;
+  this.description = description;
+}
+
+HttpError.prototype = {
+  toString() {
+    return this.code + " " + this.description;
+  },
+};
+
+/**
+ * Errors thrown to trigger specific HTTP server responses.
+ */
+export var HTTP_400 = new HttpError(400, "Bad Request");
+
+export var HTTP_401 = new HttpError(401, "Unauthorized");
+export var HTTP_402 = new HttpError(402, "Payment Required");
+export var HTTP_403 = new HttpError(403, "Forbidden");
+export var HTTP_404 = new HttpError(404, "Not Found");
+export var HTTP_405 = new HttpError(405, "Method Not Allowed");
+export var HTTP_406 = new HttpError(406, "Not Acceptable");
+export var HTTP_407 = new HttpError(407, "Proxy Authentication Required");
+export var HTTP_408 = new HttpError(408, "Request Timeout");
+export var HTTP_409 = new HttpError(409, "Conflict");
+export var HTTP_410 = new HttpError(410, "Gone");
+export var HTTP_411 = new HttpError(411, "Length Required");
+export var HTTP_412 = new HttpError(412, "Precondition Failed");
+export var HTTP_413 = new HttpError(413, "Request Entity Too Large");
+export var HTTP_414 = new HttpError(414, "Request-URI Too Long");
+export var HTTP_415 = new HttpError(415, "Unsupported Media Type");
+export var HTTP_417 = new HttpError(417, "Expectation Failed");
+export var HTTP_500 = new HttpError(500, "Internal Server Error");
+export var HTTP_501 = new HttpError(501, "Not Implemented");
+export var HTTP_502 = new HttpError(502, "Bad Gateway");
+export var HTTP_503 = new HttpError(503, "Service Unavailable");
+export var HTTP_504 = new HttpError(504, "Gateway Timeout");
+export var 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;
+const INFORMATIONAL_RESPONSE_SUFFIX =
+  HIDDEN_CHAR + "informationalResponse" + 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. */
+export 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);
+}
+
+/**
+ * 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 ServerSocketIPv6 = CC(
+  "@mozilla.org/network/server-socket;1",
+  "nsIServerSocket",
+  "initIPv6"
+);
+const ServerSocketDualStack = CC(
+  "@mozilla.org/network/server-socket;1",
+  "nsIServerSocket",
+  "initDualStack"
+);
+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"
+);
+
+export function overrideBinaryStreamsForTests(
+  inputStream,
+  outputStream,
+  responseSegmentSize
+) {
+  BinaryInputStream = inputStream;
+  BinaryOutputStream = outputStream;
+  Response.SEGMENT_SIZE = responseSegmentSize;
+}
+
+/**
+ * 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));
+}
+
+/**
+ * Instantiates a new HTTP server.
+ */
+export function nsHttpServer() {
+  /** 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 = {
+  // 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(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,
+        trans
+      );
+      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, Services.tm.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(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() {
+          dumpn("*** _notifyStopped async callback");
+          self._notifyStopped();
+        },
+      };
+      Services.tm.currentThread.dispatch(
+        stopEvent,
+        Ci.nsIThread.DISPATCH_NORMAL
+      );
+    }
+  },
+
+  // NSIHTTPSERVER
+
+  //
+  // see nsIHttpServer.start
+  //
+  start(port) {
+    this._start(port, "localhost");
+  },
+
+  //
+  // see nsIHttpServer.start_ipv6
+  //
+  start_ipv6(port) {
+    this._start(port, "[::1]");
+  },
+
+  start_dualStack(port) {
+    this._start(port, "[::1]", true);
+  },
+
+  _start(port, host, dualStack) {
+    if (this._socket) {
+      throw Components.Exception("", 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 maxConnections =
+      5 +
+      Math.max(
+        Services.prefs.getIntPref(
+          "network.http.max-persistent-connections-per-server"
+        ),
+        Services.prefs.getIntPref(
+          "network.http.max-persistent-connections-per-proxy"
+        )
+      );
+
+    try {
+      var loopback = true;
+      if (
+        this._host != "127.0.0.1" &&
+        this._host != "localhost" &&
+        this._host != "[::1]"
+      ) {
+        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 socket;
+      for (var i = 100; i; i--) {
+        var temp = null;
+        if (dualStack) {
+          temp = new ServerSocketDualStack(this._port, maxConnections);
+        } else if (this._host.includes(":")) {
+          temp = new ServerSocketIPv6(
+            this._port,
+            loopback, // true = localhost, false = everybody
+            maxConnections
+          );
+        } else {
+          temp = new ServerSocket(
+            this._port,
+            loopback, // true = localhost, false = everybody
+            maxConnections
+          );
+        }
+
+        var allowed = Services.io.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?"
+        );
+      }
+
+      socket.asyncListen(this);
+      this._port = socket.port;
+      this._identity._initialize(socket.port, host, true, dualStack);
+      this._socket = socket;
+      dumpn(
+        ">>> listening on port " +
+          socket.port +
+          ", " +
+          maxConnections +
+          " pending connections"
+      );
+    } catch (e) {
+      dump("\n!!! could not start server on port " + port + ": " + e + "\n\n");
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+  },
+
+  //
+  // see nsIHttpServer.stop
+  //
+  stop(callback) {
+    if (!this._socket) {
+      throw Components.Exception("", Cr.NS_ERROR_UNEXPECTED);
+    }
+
+    // If no argument was provided to stop, return a promise.
+    let returnValue = undefined;
+    if (!callback) {
+      returnValue = new Promise(resolve => {
+        callback = resolve;
+      });
+    }
+
+    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
+
+    return returnValue;
+  },
+
+  //
+  // see nsIHttpServer.registerFile
+  //
+  registerFile(path, file, handler) {
+    if (file && (!file.exists() || file.isDirectory())) {
+      throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    this._handler.registerFile(path, file, handler);
+  },
+
+  //
+  // see nsIHttpServer.registerDirectory
+  //
+  registerDirectory(path, directory) {
+    // XXX true path validation!
+    if (
+      path.charAt(0) != "/" ||
+      path.charAt(path.length - 1) != "/" ||
+      (directory && (!directory.exists() || !directory.isDirectory()))
+    ) {
+      throw Components.Exception("", 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(path, handler) {
+    this._handler.registerPathHandler(path, handler);
+  },
+
+  //
+  // see nsIHttpServer.registerPrefixHandler
+  //
+  registerPrefixHandler(prefix, handler) {
+    this._handler.registerPrefixHandler(prefix, handler);
+  },
+
+  //
+  // see nsIHttpServer.registerErrorHandler
+  //
+  registerErrorHandler(code, handler) {
+    this._handler.registerErrorHandler(code, handler);
+  },
+
+  //
+  // see nsIHttpServer.setIndexHandler
+  //
+  setIndexHandler(handler) {
+    this._handler.setIndexHandler(handler);
+  },
+
+  //
+  // see nsIHttpServer.registerContentType
+  //
+  registerContentType(ext, type) {
+    this._handler.registerContentType(ext, type);
+  },
+
+  get connectionNumber() {
+    return this._connectionGen;
+  },
+
+  //
+  // see nsIHttpServer.serverIdentity
+  //
+  get identity() {
+    return this._identity;
+  },
+
+  //
+  // see nsIHttpServer.getState
+  //
+  getState(path, k) {
+    return this._handler._getState(path, k);
+  },
+
+  //
+  // see nsIHttpServer.setState
+  //
+  setState(path, k, v) {
+    return this._handler._setState(path, k, v);
+  },
+
+  //
+  // see nsIHttpServer.getSharedState
+  //
+  getSharedState(k) {
+    return this._handler._getSharedState(k);
+  },
+
+  //
+  // see nsIHttpServer.setSharedState
+  //
+  setSharedState(k, v) {
+    return this._handler._setSharedState(k, v);
+  },
+
+  //
+  // see nsIHttpServer.getObjectState
+  //
+  getObjectState(k) {
+    return this._handler._getObjectState(k);
+  },
+
+  //
+  // see nsIHttpServer.setObjectState
+  //
+  setObjectState(k, v) {
+    return this._handler._setObjectState(k, v);
+  },
+
+  get wrappedJSObject() {
+    return this;
+  },
+
+  // NSISUPPORTS
+
+  //
+  // see nsISupports.QueryInterface
+  //
+  QueryInterface: ChromeUtils.generateQI([
+    "nsIHttpServer",
+    "nsIServerSocketListener",
+  ]),
+
+  // 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() {
+    return this._socketClosed && !this._hasOpenConnections();
+  },
+
+  // PRIVATE IMPLEMENTATION
+
+  /** True if this server has any open connections to it, false otherwise. */
+  _hasOpenConnections() {
+    //
+    // 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() {
+    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(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();
+    }
+  },
+
+  /**
+   * Requests that the server be shut down when possible.
+   */
+  _requestQuit() {
+    dumpn(">>> requesting a quit");
+    dumpStack();
+    this._doQuit = true;
+  },
+};
+
+export var HttpServer = nsHttpServer;
+
+export class NodeServer {
+  // Executes command in the context of a node server.
+  // See handler in moz-http2.js
+  //
+  // Example use:
+  // let id = NodeServer.fork(); // id is a random string
+  // await NodeServer.execute(id, `"hello"`)
+  // > "hello"
+  // await NodeServer.execute(id, `(() => "hello")()`)
+  // > "hello"
+  // await NodeServer.execute(id, `(() => var_defined_on_server)()`)
+  // > "0"
+  // await NodeServer.execute(id, `var_defined_on_server`)
+  // > "0"
+  // function f(param) { if (param) return param; return "bla"; }
+  // await NodeServer.execute(id, f); // Defines the function on the server
+  // await NodeServer.execute(id, `f()`) // executes defined function
+  // > "bla"
+  // let result = await NodeServer.execute(id, `f("test")`);
+  // > "test"
+  // await NodeServer.kill(id); // shuts down the server
+
+  // Forks a new node server using moz-http2-child.js as a starting point
+  static fork() {
+    return this.sendCommand("", "/fork");
+  }
+  // Executes command in the context of the node server indicated by `id`
+  static execute(id, command) {
+    return this.sendCommand(command, `/execute/${id}`);
+  }
+  // Shuts down the server
+  static kill(id) {
+    return this.sendCommand("", `/kill/${id}`);
+  }
+
+  // Issues a request to the node server (handler defined in moz-http2.js)
+  // This method should not be called directly.
+  static sendCommand(command, path) {
+    let h2Port = Services.env.get("MOZNODE_EXEC_PORT");
+    if (!h2Port) {
+      throw new Error("Could not find MOZNODE_EXEC_PORT");
+    }
+
+    let req = new XMLHttpRequest();
+    const serverIP =
+      AppConstants.platform == "android" ? "10.0.2.2" : "127.0.0.1";
+    req.open("POST", `http://${serverIP}:${h2Port}${path}`);
+    req.channel.QueryInterface(Ci.nsIHttpChannelInternal).bypassProxy = true;
+
+    // Passing a function to NodeServer.execute will define that function
+    // in node. It can be called in a later execute command.
+    let isFunction = function (obj) {
+      return !!(obj && obj.constructor && obj.call && obj.apply);
+    };
+    let payload = command;
+    if (isFunction(command)) {
+      payload = `${command.name} = ${command.toString()};`;
+    }
+
+    return new Promise((resolve, reject) => {
+      req.onload = () => {
+        let x = null;
+
+        if (req.statusText != "OK") {
+          reject(`XHR request failed: ${req.statusText}`);
+          return;
+        }
+
+        try {
+          x = JSON.parse(req.responseText);
+        } catch (e) {
+          reject(`Failed to parse ${req.responseText} - ${e}`);
+          return;
+        }
+
+        if (x.error) {
+          let e = new Error(x.error, "", 0);
+          e.stack = x.errorStack;
+          reject(e);
+          return;
+        }
+        resolve(x.result);
+      };
+      req.onerror = e => {
+        reject(e);
+      };
+
+      req.send(payload.toString());
+    });
+  }
+}
+
+//
+// RFC 2396 section 3.2.2:
+//
+// host        = hostname | IPv4address
+// hostname    = *( domainlabel "." ) toplabel [ "." ]
+// domainlabel = alphanum | alphanum *( alphanum | "-" ) alphanum
+// toplabel    = alpha | alpha *( alphanum | "-" ) alphanum
+// IPv4address = 1*digit "." 1*digit "." 1*digit "." 1*digit
+//
+// IPv6 addresses are notably lacking in the above definition of 'host'.
+// RFC 2732 section 3 extends the host definition:
+// host          = hostname | IPv4address | IPv6reference
+// ipv6reference = "[" IPv6address "]"
+//
+// RFC 3986 supersedes RFC 2732 and offers a more precise definition of a IPv6
+// address. For simplicity, the regexp below captures all canonical IPv6
+// addresses (e.g. [::1]), but may also match valid non-canonical IPv6 addresses
+// (e.g. [::127.0.0.1]) and even invalid bracketed addresses ([::], [99999::]).
+
+const HOST_REGEX = new RegExp(
+  "^(?:" +
+    // *( domainlabel "." )
+    "(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\\.)*" +
+    // toplabel [ "." ]
+    "[a-z](?:[a-z0-9-]*[a-z0-9])?\\.?" +
+    "|" +
+    // IPv4 address
+    "\\d+\\.\\d+\\.\\d+\\.\\d+" +
+    "|" +
+    // IPv6 addresses (e.g. [::1])
+    "\\[[:0-9a-f]+\\]" +
+    ")$",
+  "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 Components.Exception("", Cr.NS_ERROR_NOT_INITIALIZED);
+    }
+    return this._primaryScheme;
+  },
+
+  //
+  // see nsIHttpServerIdentity.primaryHost
+  //
+  get primaryHost() {
+    if (this._primaryPort === -1) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_INITIALIZED);
+    }
+    return this._primaryHost;
+  },
+
+  //
+  // see nsIHttpServerIdentity.primaryPort
+  //
+  get primaryPort() {
+    if (this._primaryPort === -1) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_INITIALIZED);
+    }
+    return this._primaryPort;
+  },
+
+  //
+  // see nsIHttpServerIdentity.add
+  //
+  add(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(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(scheme, host, port) {
+    this._validate(scheme, host, port);
+
+    return (
+      "x" + host in this._locations &&
+      scheme === this._locations["x" + host][port]
+    );
+  },
+
+  //
+  // see nsIHttpServerIdentity.has
+  //
+  getScheme(host, port) {
+    this._validate("http", host, port);
+
+    var entry = this._locations["x" + host];
+    if (!entry) {
+      return "";
+    }
+
+    return entry[port] || "";
+  },
+
+  //
+  // see nsIHttpServerIdentity.setPrimary
+  //
+  setPrimary(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: ChromeUtils.generateQI(["nsIHttpServerIdentity"]),
+
+  // PRIVATE IMPLEMENTATION
+
+  /**
+   * Initializes the primary name for the corresponding server, based on the
+   * provided port number.
+   */
+  _initialize(port, host, addSecondaryDefault, dualStack) {
+    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") {
+      if (host.includes(":")) {
+        this.add("http", "[::1]", port);
+        if (dualStack) {
+          this.add("http", "127.0.0.1", port);
+        }
+      } else {
+        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() {
+    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(scheme, host, port) {
+    if (scheme !== "http" && scheme !== "https") {
+      dumpn("*** server only supports http/https schemes: '" + scheme + "'");
+      dumpStack();
+      throw Components.Exception("", Cr.NS_ERROR_ILLEGAL_VALUE);
+    }
+    if (!HOST_REGEX.test(host)) {
+      dumpn("*** unexpected host: '" + host + "'");
+      throw Components.Exception("", Cr.NS_ERROR_ILLEGAL_VALUE);
+    }
+    if (port < 0 || port > 65535) {
+      dumpn("*** unexpected port: '" + port + "'");
+      throw Components.Exception("", 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,
+  transport
+) {
+  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;
+
+  /** Reference to the underlying transport. */
+  this.transport = transport;
+
+  /**
+   * 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() {
+    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(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(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() {
+    return (
+      "<Connection(" +
+      this.number +
+      (this.request ? ", " + this.request.path : "") +
+      "): " +
+      (this._closed ? "closed" : "open") +
+      ">"
+    );
+  },
+
+  requestStarted() {
+    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(input) {
+    dumpn(
+      "*** onInputStreamReady(input=" +
+        input +
+        ") on thread " +
+        Services.tm.currentThread +
+        " (main is " +
+        Services.tm.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, Services.tm.currentThread);
+    }
+  },
+
+  //
+  // see nsISupports.QueryInterface
+  //
+  QueryInterface: ChromeUtils.generateQI(["nsIInputStreamCallback"]),
+
+  // PRIVATE API
+
+  /**
+   * Processes unprocessed, downloaded data as a request line.
+   *
+   * @returns boolean
+   *   true iff the request line has been fully processed
+   */
+  _processRequestLine() {
+    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() {
+    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() {
+    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)
+        );
+        data.length = count;
+
+        var bos = new BinaryOutputStream(this._metadata._bodyOutputStream);
+        bos.writeByteArray(data);
+        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() {
+    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.lastIndexOf(":");
+        if (hostPort.lastIndexOf("]") > colon) {
+          colon = -1;
+        }
+        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(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() {
+    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(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 new Error("unsupported HTTP version");
+      }
+    } catch (e) {
+      // we support HTTP/1.0 and HTTP/1.1 only
+      throw HTTP_501;
+    }
+
+    var fullPath = request[1];
+
+    if (metadata._method == "CONNECT") {
+      metadata._path = "CONNECT";
+      metadata._scheme = "https";
+      [metadata._host, metadata._port] = fullPath.split(":");
+      return;
+    }
+
+    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 = Services.io.newURI(fullPath);
+        fullPath = uri.pathQueryRef;
+        scheme = uri.scheme;
+        host = uri.asciiHost;
+        if (host.includes(":")) {
+          // If the host still contains a ":", then it is an IPv6 address.
+          // IPv6 addresses-as-host are registered with brackets, so we need to
+          // wrap the host in brackets because nsIURI's host lacks them.
+          // This inconsistency in nsStandardURL is tracked at bug 1195459.
+          host = `[${host}]`;
+        }
+        metadata._host = host;
+        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() {
+    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.
+ */
+export 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(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(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 && 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() {
+    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.nextFile;
+    let 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 {
+      let 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 maybeAddHeadersInternal(
+  file,
+  metadata,
+  response,
+  informationalResponse
+) {
+  var name = file.leafName;
+  if (name.charAt(name.length - 1) == HIDDEN_CHAR) {
+    name = name.substring(0, name.length - 1);
+  }
+
+  var headerFile = file.parent;
+  if (!informationalResponse) {
+    headerFile.append(name + HEADERS_SUFFIX);
+  } else {
+    headerFile.append(name + INFORMATIONAL_RESPONSE_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);
+      }
+
+      if (!informationalResponse) {
+        response.setStatusLine(
+          metadata.httpVersion,
+          parseInt(code, 10),
+          description
+        );
+      } else {
+        response.setInformationalResponseStatusLine(
+          metadata.httpVersion,
+          parseInt(code, 10),
+          description
+        );
+      }
+
+      line.value = "";
+      more = lis.readLine(line);
+    } else if (informationalResponse) {
+      // An informational response must have a status line.
+      return;
+    }
+
+    // headers
+    while (more || line.value != "") {
+      var header = line.value;
+      var colon = header.indexOf(":");
+
+      if (!informationalResponse) {
+        response.setHeader(
+          header.substring(0, colon),
+          header.substring(colon + 1, header.length),
+          false
+        ); // allow overriding server-set headers
+      } else {
+        response.setInformationalResponseHeader(
+          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();
+  }
+}
+
+function maybeAddHeaders(file, metadata, response) {
+  maybeAddHeadersInternal(file, metadata, response, false);
+}
+
+function maybeAddInformationalResponse(file, metadata, response) {
+  maybeAddHeadersInternal(file, metadata, response, true);
+}
+
+/**
+ * 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->nsIFile 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(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) {
+            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(path, file, handler) {
+    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;
+      }
+
+      dumpn("*** responding '" + path + "' as mapping to " + file.path);
+
+      response.setStatusLine(request.httpVersion, 200, "OK");
+      if (typeof handler === "function") {
+        handler(request, response);
+      }
+      self._writeFileResponse(request, file, response, 0, file.fileSize);
+    };
+  },
+
+  //
+  // see nsIHttpServer.registerPathHandler
+  //
+  registerPathHandler(path, handler) {
+    if (!path.length) {
+      throw Components.Exception(
+        "Handler path cannot be empty",
+        Cr.NS_ERROR_INVALID_ARG
+      );
+    }
+
+    // XXX true path validation!
+    if (path.charAt(0) != "/" && path != "CONNECT") {
+      throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    this._handlerToField(handler, this._overridePaths, path);
+  },
+
+  //
+  // see nsIHttpServer.registerPrefixHandler
+  //
+  registerPrefixHandler(path, handler) {
+    // XXX true path validation!
+    if (path.charAt(0) != "/" || path.charAt(path.length - 1) != "/") {
+      throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+    }
+
+    this._handlerToField(handler, this._overridePrefixes, path);
+  },
+
+  //
+  // see nsIHttpServer.registerDirectory
+  //
+  registerDirectory(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 Components.Exception("", 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(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(handler) {
+    if (!handler) {
+      handler = defaultIndexHandler;
+    } else if (typeof handler != "function") {
+      handler = createHandlerFunc(handler);
+    }
+
+    this._indexHandler = handler;
+  },
+
+  //
+  // see nsIHttpServer.registerContentType
+  //
+  registerContentType(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(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(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 : nsIFile
+   *   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(metadata, file, response, offset, count) {
+    const PR_RDONLY = 0x01;
+
+    var type = this._getTypeFromFile(file);
+    if (type === SJS_TYPE) {
+      let fis = new FileInputStream(
+        file,
+        PR_RDONLY,
+        PERMS_READONLY,
+        Ci.nsIFileInputStream.CLOSE_ON_EOF
+      );
+
+      try {
+        // If you update the list of imports, please update the list in
+        // tools/lint/eslint/eslint-plugin-mozilla/lib/environments/sjs.js
+        // as well.
+        var s = Cu.Sandbox(Cu.getGlobalForObject({}), {
+          wantGlobalProperties: [
+            "atob",
+            "btoa",
+            "ChromeUtils",
+            "IOUtils",
+            "PathUtils",
+            "TextDecoder",
+            "TextEncoder",
+            "URLSearchParams",
+            "URL",
+          ],
+        });
+        s.importFunction(dump, "dump");
+        s.importFunction(Services, "Services");
+
+        // 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;
+          let uri = Services.io.newFileURI(file);
+          Services.scriptloader.loadSubScript(uri.spec, s);
+        } 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);
+      maybeAddInformationalResponse(file, metadata, response);
+      maybeAddHeaders(file, metadata, response);
+      // Allow overriding Content-Length
+      try {
+        response.getHeader("Content-Length");
+      } catch (e) {
+        response.setHeader("Content-Length", "" + count, false);
+      }
+
+      let 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 () {
+        Services.tm.currentThread.dispatch(
+          writeData,
+          Ci.nsIThread.DISPATCH_NORMAL
+        );
+      };
+
+      var input = new BinaryInputStream(fis);
+      var output = new BinaryOutputStream(response.bodyOutputStream);
+      var writeData = {
+        run() {
+          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);
+            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(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(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(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(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(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(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(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/mime;1"]
+        .getService(Ci.nsIMIMEService)
+        .getTypeFromFile(file);
+    } catch (e) {
+      return "application/octet-stream";
+    }
+  },
+
+  /**
+   * Returns the nsIFile 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 nsIFile
+   *   the file to be sent as the response to a request for the path
+   */
+  _getFileForPath(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 &&
+          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(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(errorCode, metadata, response) {
+    if (!metadata) {
+      throw Components.Exception("", 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(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(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(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(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(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(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(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 nsIFile 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 : nsIFile
+   *   the file to map to key, or null to remove a mapping
+   */
+  put(key, value) {
+    if (value) {
+      this._map[key] = value.clone();
+    } else {
+      delete this._map[key];
+    }
+  },
+
+  /**
+   * Returns a clone of the nsIFile mapped to key, or null if no such
+   * mapping exists.
+   *
+   * @param key : string
+   *   key to which the returned file maps
+   * @returns nsIFile
+   *   a clone of the mapped file, or null if no mapping exists
+   */
+  get(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();
+
+  /**
+   * Informational response:
+   * For example 103 Early Hint
+   **/
+  this._informationalResponseHttpVersion = nsHttpVersion.HTTP_1_1;
+  this._informationalResponseHttpCode = 0;
+  this._informationalResponseHttpDescription = "";
+  this._informationalResponseHeaders = new nsHttpHeaders();
+  this._informationalResponseSet = false;
+
+  /**
+   * 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 Components.Exception("", 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(data) {
+    if (this._finished) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+
+    var dataAsString = String(data);
+    this.bodyOutputStream.write(dataAsString, dataAsString.length);
+  },
+
+  //
+  // see nsIHttpResponse.setStatusLine
+  //
+  setStatusLineInternal(httpVersion, code, description, informationalResponse) {
+    if (this._finished || this._powerSeized) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+
+    if (!informationalResponse) {
+      if (!this._headers) {
+        throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+      }
+    } else if (!this._informationalResponseHeaders) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    this._ensureAlive();
+
+    if (!(code >= 0 && code < 1000)) {
+      throw Components.Exception("", 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 Components.Exception("", 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 Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+      }
+    }
+
+    // set the values only after validation to preserve atomicity
+    if (!informationalResponse) {
+      this._httpDescription = description;
+      this._httpCode = code;
+      this._httpVersion = httpVer;
+    } else {
+      this._informationalResponseSet = true;
+      this._informationalResponseHttpDescription = description;
+      this._informationalResponseHttpCode = code;
+      this._informationalResponseHttpVersion = httpVer;
+    }
+  },
+
+  //
+  // see nsIHttpResponse.setStatusLine
+  //
+  setStatusLine(httpVersion, code, description) {
+    this.setStatusLineInternal(httpVersion, code, description, false);
+  },
+
+  setInformationalResponseStatusLine(httpVersion, code, description) {
+    this.setStatusLineInternal(httpVersion, code, description, true);
+  },
+
+  //
+  // see nsIHttpResponse.setHeader
+  //
+  setHeader(name, value, merge) {
+    if (!this._headers || this._finished || this._powerSeized) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    this._ensureAlive();
+
+    this._headers.setHeader(name, value, merge);
+  },
+
+  setInformationalResponseHeader(name, value, merge) {
+    if (
+      !this._informationalResponseHeaders ||
+      this._finished ||
+      this._powerSeized
+    ) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    this._ensureAlive();
+
+    this._informationalResponseHeaders.setHeader(name, value, merge);
+  },
+
+  setHeaderNoCheck(name, value) {
+    if (!this._headers || this._finished || this._powerSeized) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    this._ensureAlive();
+
+    this._headers.setHeaderNoCheck(name, value);
+  },
+
+  setInformationalHeaderNoCheck(name, value) {
+    if (!this._headers || this._finished || this._powerSeized) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    this._ensureAlive();
+
+    this._informationalResponseHeaders.setHeaderNoCheck(name, value);
+  },
+
+  //
+  // see nsIHttpResponse.processAsync
+  //
+  processAsync() {
+    if (this._finished) {
+      throw Components.Exception("", Cr.NS_ERROR_UNEXPECTED);
+    }
+    if (this._powerSeized) {
+      throw Components.Exception("", 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() {
+    if (this._processAsync) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+    if (this._finished) {
+      throw Components.Exception("", 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() {
+    if (!this._processAsync && !this._powerSeized) {
+      throw Components.Exception("", 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: ChromeUtils.generateQI(["nsIHttpResponse"]),
+
+  // 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(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() {
+    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() {
+    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
+   * @param truncateConnection : Boolean
+   *   ensures that we truncate the connection using an RST packet, so the
+   *   client testing code is aware that an error occurred, otherwise it may
+   *   consider the response as valid.
+   */
+  abort(e, truncateConnection = false) {
+    dumpn("*** abort(<" + e + ">)");
+
+    if (truncateConnection) {
+      dumpn("*** truncate connection");
+      this._connection.transport.setLinger(true, 0);
+    }
+
+    // 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.
+      Services.tm.currentThread.dispatch(
+        {
+          run() {
+            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() {
+    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() {
+    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() {
+    dumpn("*** _sendHeaders()");
+
+    NS_ASSERT(this._headers);
+    NS_ASSERT(this._informationalResponseHeaders);
+    NS_ASSERT(!this._powerSeized);
+
+    var preambleData = [];
+
+    // Informational response, e.g. 103
+    if (this._informationalResponseSet) {
+      // request-line
+      let statusLine =
+        "HTTP/" +
+        this._informationalResponseHttpVersion +
+        " " +
+        this._informationalResponseHttpCode +
+        " " +
+        this._informationalResponseHttpDescription +
+        "\r\n";
+      preambleData.push(statusLine);
+
+      // headers
+      let headEnum = this._informationalResponseHeaders.enumerator;
+      while (headEnum.hasMoreElements()) {
+        let fieldName = headEnum
+          .getNext()
+          .QueryInterface(Ci.nsISupportsString).data;
+        let values =
+          this._informationalResponseHeaders.getHeaderValues(fieldName);
+        for (let i = 0, sz = values.length; i < sz; i++) {
+          preambleData.push(fieldName + ": " + values[i] + "\r\n");
+        }
+      }
+      // end request-line/headers
+      preambleData.push("\r\n");
+    }
+
+    // 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
+    preambleData.push(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(request) {
+        dumpn("*** preamble copying started");
+      },
+
+      onStopRequest(request, 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: ChromeUtils.generateQI(["nsIRequestObserver"]),
+    };
+
+    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() {
+    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(request) {
+        dumpn("*** onStartRequest");
+      },
+
+      onStopRequest(request, 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: ChromeUtils.generateQI(["nsIRequestObserver"]),
+    };
+
+    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() {
+    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 Components.Exception("", 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
+ */
+export function WriteThroughCopier(source, sink, observer, context) {
+  if (!source || !sink || !observer) {
+    throw Components.Exception("", 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);
+    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: ChromeUtils.generateQI([
+    "nsIInputStreamCallback",
+    "nsIOutputStreamCallback",
+    "nsIRequest",
+  ]),
+
+  // 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(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 Components.Exception("", Cr.NS_BASE_STREAM_CLOSED);
+      }
+    } catch (e) {
+      let rv;
+      if (streamClosed(e)) {
+        dumpn("*** input stream closed");
+        rv = bytesWanted === 0 ? Cr.NS_OK : Cr.NS_ERROR_UNEXPECTED;
+      } else {
+        dumpn("!!! unexpected error reading from input, canceling: " + e);
+        rv = Cr.NS_ERROR_UNEXPECTED;
+      }
+
+      this._doneReadingSource(rv);
+      return;
+    }
+
+    var pendingData = this._pendingData;
+
+    NS_ASSERT(bytesConsumed > 0);
+    NS_ASSERT(!!pendingData.length, "no pending data somehow?");
+    NS_ASSERT(
+      !!pendingData[pendingData.length - 1].length,
+      "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(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, "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,
+          "stream-blocking exception with no data to write?"
+        );
+        NS_ASSERT(
+          !!pendingData[0].length,
+          "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) {
+        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() {
+    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(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(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(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(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() {
+        dumpn("*** onStopRequest async callback");
+
+        self._completed = true;
+        try {
+          self._observer.onStopRequest(self, self.status);
+        } catch (e) {
+          NS_ASSERT(
+            false,
+            "how are we throwing an exception here?  we control " +
+              "all the callers!  " +
+              e
+          );
+        }
+      },
+    };
+
+    Services.tm.currentThread.dispatch(event, Ci.nsIThread.DISPATCH_NORMAL);
+  },
+
+  /**
+   * Kicks off another wait for more data to be available from the input stream.
+   */
+  _waitToReadData() {
+    dumpn("*** _waitToReadData");
+    this._source.asyncWait(
+      this,
+      0,
+      Response.SEGMENT_SIZE,
+      Services.tm.mainThread
+    );
+  },
+
+  /**
+   * Kicks off another wait until data can be written to the output stream.
+   */
+  _waitToWriteData() {
+    dumpn("*** _waitToWriteData");
+
+    var pendingData = this._pendingData;
+    NS_ASSERT(!!pendingData.length, "no pending data to write?");
+    NS_ASSERT(!!pendingData[0].length, "buffered an empty write?");
+
+    this._sink.asyncWait(
+      this,
+      0,
+      pendingData[0].length,
+      Services.tm.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() {
+    dumpn("*** _waitForSinkClosure");
+
+    this._sink.asyncWait(
+      this,
+      Ci.nsIAsyncOutputStream.WAIT_CLOSURE_ONLY,
+      0,
+      Services.tm.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(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(fieldName) {
+    if (fieldName == "") {
+      dumpn("*** Empty fieldName");
+      throw Components.Exception("", 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 Components.Exception("", 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(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(/ +$/, "");
+
+    // that should have taken care of all CTLs, so val should contain no CTLs
+    dumpn("*** Normalized value: '" + val + "'");
+    for (var i = 0, len = val.length; i < len; i++) {
+      if (isCTL(val.charCodeAt(i))) {
+        dump("*** Char " + i + " has charcode " + val.charCodeAt(i));
+        throw Components.Exception("", Cr.NS_ERROR_INVALID_ARG);
+      }
+    }
+
+    // XXX disallows quoted-pair where CHAR is a CTL -- will not invalidly
+    //     normalize, however, so this can be construed as a tightening of the
+    //     spec and not entirely as a bug
+    return val;
+  },
+};
+
+/**
+ * Converts the given string into a string which is safe for use in an HTML
+ * context.
+ *
+ * @param str : string
+ *   the string to make HTML-safe
+ * @returns string
+ *   an HTML-safe version of str
+ */
+function htmlEscape(str) {
+  // this is naive, but it'll work
+  var s = "";
+  for (var i = 0; i < str.length; i++) {
+    s += "&#" + str.charCodeAt(i) + ";";
+  }
+  return s;
+}
+
+/**
+ * Constructs an object representing an HTTP version (see section 3.1).
+ *
+ * @param versionString
+ *   a string of the form "#.#", where # is an non-negative decimal integer with
+ *   or without leading zeros
+ * @throws
+ *   if versionString does not specify a valid HTTP version number
+ */
+function nsHttpVersion(versionString) {
+  var matches = /^(\d+)\.(\d+)$/.exec(versionString);
+  if (!matches) {
+    throw new Error("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 new Error("Not a valid HTTP version!");
+  }
+}
+nsHttpVersion.prototype = {
+  /**
+   * Returns the standard string representation of the HTTP version represented
+   * by this (e.g., "1.1").
+   */
+  toString() {
+    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(otherVersion) {
+    return this.major == otherVersion.major && this.minor == otherVersion.minor;
+  },
+
+  /** True if this >= otherVersion, false otherwise. */
+  atLeast(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.
+ */
+export 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(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 <https://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];
+    }
+  },
+
+  setHeaderNoCheck(fieldName, fieldValue) {
+    var name = headerUtils.normalizeFieldName(fieldName);
+    var value = headerUtils.normalizeFieldValue(fieldValue);
+    if (name in this._headers) {
+      this._headers[name].push(value);
+    } 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(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(fieldName) {
+    var name = headerUtils.normalizeFieldName(fieldName);
+
+    if (name in this._headers) {
+      return this._headers[name];
+    }
+    throw Components.Exception("", 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(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() {
+    return this._nextIndex < this._items.length;
+  },
+  getNext() {
+    if (!this.hasMoreElements()) {
+      throw Components.Exception("", Cr.NS_ERROR_NOT_AVAILABLE);
+    }
+
+    return this._items[this._nextIndex++];
+  },
+  [Symbol.iterator]() {
+    return this._items.values();
+  },
+  QueryInterface: ChromeUtils.generateQI(["nsISimpleEnumerator"]),
+};
+
+/**
+ * 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(name) {
+    return this._headers.getHeader(name);
+  },
+
+  //
+  // see nsIHttpRequest.hasHeader
+  //
+  hasHeader(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(name) {
+    this._ensurePropertyBag();
+    return this._bag.getProperty(name);
+  },
+
+  // NSISUPPORTS
+
+  //
+  // see nsISupports.QueryInterface
+  //
+  QueryInterface: ChromeUtils.generateQI(["nsIHttpRequest"]),
+
+  // PRIVATE IMPLEMENTATION
+
+  /** Ensures a property bag has been created for ad-hoc behaviors. */
+  _ensurePropertyBag() {
+    if (!this._bag) {
+      this._bag = new WritablePropertyBag();
+    }
+  },
+};