/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

"use strict";

/* global Pipe, ScriptableInputStream, uneval */

const {Constructor: CC, classes: Cc, utils: Cu, results: Cr} = Components;

Cu.import("resource://gre/modules/Services.jsm");
Cu.import("resource://gre/modules/EventEmitter.jsm");
const {StreamUtils} =
    Cu.import("chrome://marionette/content/stream-utils.js", {});
const {Packet, JSONPacket, BulkPacket} =
    Cu.import("chrome://marionette/content/packets.js", {});

const defer = function() {
  let deferred = {
    promise: new Promise((resolve, reject) => {
      deferred.resolve = resolve;
      deferred.reject = reject;
    }),
  };
  return deferred;
};

const executeSoon = function(func) {
  Services.tm.dispatchToMainThread(func);
};

const flags = {wantVerbose: false, wantLogging: false};

const dumpv =
  flags.wantVerbose ?
  function(msg) { dump(msg + "\n"); } :
  function() {};

const Pipe = CC("@mozilla.org/pipe;1", "nsIPipe", "init");

const ScriptableInputStream = CC("@mozilla.org/scriptableinputstream;1",
    "nsIScriptableInputStream", "init");

this.EXPORTED_SYMBOLS = ["DebuggerTransport"];

const PACKET_HEADER_MAX = 200;

/**
 * An adapter that handles data transfers between the debugger client
 * and server. It can work with both nsIPipe and nsIServerSocket
 * transports so long as the properly created input and output streams
 * are specified.  (However, for intra-process connections,
 * LocalDebuggerTransport, below, is more efficient than using an nsIPipe
 * pair with DebuggerTransport.)
 *
 * @param {nsIAsyncInputStream} input
 *     The input stream.
 * @param {nsIAsyncOutputStream} output
 *     The output stream.
 *
 * Given a DebuggerTransport instance dt:
 * 1) Set dt.hooks to a packet handler object (described below).
 * 2) Call dt.ready() to begin watching for input packets.
 * 3) Call dt.send() / dt.startBulkSend() to send packets.
 * 4) Call dt.close() to close the connection, and disengage from
 *    the event loop.
 *
 * A packet handler is an object with the following methods:
 *
 * - onPacket(packet) - called when we have received a complete packet.
 *   |packet| is the parsed form of the packet --- a JavaScript value, not
 *   a JSON-syntax string.
 *
 * - onBulkPacket(packet) - called when we have switched to bulk packet
 *   receiving mode. |packet| is an object containing:
 *   * actor:  Name of actor that will receive the packet
 *   * type:   Name of actor's method that should be called on receipt
 *   * length: Size of the data to be read
 *   * stream: This input stream should only be used directly if you
 *             can ensure that you will read exactly |length| bytes and
 *             will not close the stream when reading is complete
 *   * done:   If you use the stream directly (instead of |copyTo|
 *             below), you must signal completion by resolving/rejecting
 *             this deferred.  If it's rejected, the transport will
 *             be closed.  If an Error is supplied as a rejection value,
 *             it will be logged via |dump|.  If you do use |copyTo|,
 *             resolving is taken care of for you when copying completes.
 *   * copyTo: A helper function for getting your data out of the
 *             stream that meets the stream handling requirements above,
 *             and has the following signature:
 *
 *             @param nsIAsyncOutputStream {output}
 *                 The stream to copy to.
 *
 *             @return {Promise}
 *                 The promise is resolved when copying completes or
 *                 rejected if any (unexpected) errors occur.  This object
 *                 also emits "progress" events for each chunk that is
 *                 copied.  See stream-utils.js.
 *
 * - onClosed(reason) - called when the connection is closed. |reason|
 *   is an optional nsresult or object, typically passed when the
 *   transport is closed due to some error in a underlying stream.
 *
 * See ./packets.js and the Remote Debugging Protocol specification for
 * more details on the format of these packets.
 *
 * @class
 */
function DebuggerTransport(input, output) {
  EventEmitter.decorate(this);

  this._input = input;
  this._scriptableInput = new ScriptableInputStream(input);
  this._output = output;

  // The current incoming (possibly partial) header, which will determine
  // which type of Packet |_incoming| below will become.
  this._incomingHeader = "";
  // The current incoming Packet object
  this._incoming = null;
  // A queue of outgoing Packet objects
  this._outgoing = [];

  this.hooks = null;
  this.active = false;

  this._incomingEnabled = true;
  this._outgoingEnabled = true;

  this.close = this.close.bind(this);
}

DebuggerTransport.prototype = {
  /**
   * Transmit an object as a JSON packet.
   *
   * This method returns immediately, without waiting for the entire
   * packet to be transmitted, registering event handlers as needed to
   * transmit the entire packet. Packets are transmitted in the order they
   * are passed to this method.
   */
  send(object) {
    this.emit("send", object);

    let packet = new JSONPacket(this);
    packet.object = object;
    this._outgoing.push(packet);
    this._flushOutgoing();
  },

  /**
   * Transmit streaming data via a bulk packet.
   *
   * This method initiates the bulk send process by queuing up the header
   * data.  The caller receives eventual access to a stream for writing.
   *
   * N.B.: Do *not* attempt to close the stream handed to you, as it
   * will continue to be used by this transport afterwards.  Most users
   * should instead use the provided |copyFrom| function instead.
   *
   * @param {Object} header
   *     This is modeled after the format of JSON packets above, but does
   *     not actually contain the data, but is instead just a routing
   *     header:
   *
   *       - actor:  Name of actor that will receive the packet
   *       - type:   Name of actor's method that should be called on receipt
   *       - length: Size of the data to be sent
   *
   * @return {Promise}
   *     The promise will be resolved when you are allowed to write to
   *     the stream with an object containing:
   *
   *       - stream:   This output stream should only be used directly
   *                   if you can ensure that you will write exactly
   *                   |length| bytes and will not close the stream when
   *                    writing is complete.
   *       - done:     If you use the stream directly (instead of
   *                   |copyFrom| below), you must signal completion by
   *                   resolving/rejecting this deferred.  If it's
   *                   rejected, the transport will be closed.  If an
   *                   Error is supplied as a rejection value, it will
   *                   be logged via |dump|.  If you do use |copyFrom|,
   *                   resolving is taken care of for you when copying
   *                   completes.
   *       - copyFrom: A helper function for getting your data onto the
   *                   stream that meets the stream handling requirements
   *                   above, and has the following signature:
   *
   *                   @param {nsIAsyncInputStream} input
   *                       The stream to copy from.
   *
   *                   @return {Promise}
   *                       The promise is resolved when copying completes
   *                       or rejected if any (unexpected) errors occur.
   *                       This object also emits "progress" events for
   *                       each chunkthat is copied.  See stream-utils.js.
   */
  startBulkSend(header) {
    this.emit("startbulksend", header);

    let packet = new BulkPacket(this);
    packet.header = header;
    this._outgoing.push(packet);
    this._flushOutgoing();
    return packet.streamReadyForWriting;
  },

  /**
   * Close the transport.
   *
   * @param {(nsresult|object)=} reason
   *     The status code or error message that corresponds to the reason
   *     for closing the transport (likely because a stream closed
   *     or failed).
   */
  close(reason) {
    this.emit("close", reason);

    this.active = false;
    this._input.close();
    this._scriptableInput.close();
    this._output.close();
    this._destroyIncoming();
    this._destroyAllOutgoing();
    if (this.hooks) {
      this.hooks.onClosed(reason);
      this.hooks = null;
    }
    if (reason) {
      dumpv("Transport closed: " + reason);
    } else {
      dumpv("Transport closed.");
    }
  },

  /**
   * The currently outgoing packet (at the top of the queue).
   */
  get _currentOutgoing() {
    return this._outgoing[0];
  },

  /**
   * Flush data to the outgoing stream.  Waits until the output
   * stream notifies us that it is ready to be written to (via
   * onOutputStreamReady).
   */
  _flushOutgoing() {
    if (!this._outgoingEnabled || this._outgoing.length === 0) {
      return;
    }

    // If the top of the packet queue has nothing more to send, remove it.
    if (this._currentOutgoing.done) {
      this._finishCurrentOutgoing();
    }

    if (this._outgoing.length > 0) {
      let threadManager = Cc["@mozilla.org/thread-manager;1"].getService();
      this._output.asyncWait(this, 0, 0, threadManager.currentThread);
    }
  },

  /**
   * Pause this transport's attempts to write to the output stream.
   * This is used when we've temporarily handed off our output stream for
   * writing bulk data.
   */
  pauseOutgoing() {
    this._outgoingEnabled = false;
  },

  /**
   * Resume this transport's attempts to write to the output stream.
   */
  resumeOutgoing() {
    this._outgoingEnabled = true;
    this._flushOutgoing();
  },

  // nsIOutputStreamCallback
  /**
   * This is called when the output stream is ready for more data to
   * be written.  The current outgoing packet will attempt to write some
   * amount of data, but may not complete.
   */
  onOutputStreamReady(stream) {
    if (!this._outgoingEnabled || this._outgoing.length === 0) {
      return;
    }

    try {
      this._currentOutgoing.write(stream);
    } catch (e) {
      if (e.result != Cr.NS_BASE_STREAM_WOULD_BLOCK) {
        this.close(e.result);
        return;
      }
      throw e;
    }

    this._flushOutgoing();
  },

  /**
   * Remove the current outgoing packet from the queue upon completion.
   */
  _finishCurrentOutgoing() {
    if (this._currentOutgoing) {
      this._currentOutgoing.destroy();
      this._outgoing.shift();
    }
  },

  /**
   * Clear the entire outgoing queue.
   */
  _destroyAllOutgoing() {
    for (let packet of this._outgoing) {
      packet.destroy();
    }
    this._outgoing = [];
  },

  /**
   * Initialize the input stream for reading. Once this method has been
   * called, we watch for packets on the input stream, and pass them to
   * the appropriate handlers via this.hooks.
   */
  ready() {
    this.active = true;
    this._waitForIncoming();
  },

  /**
   * Asks the input stream to notify us (via onInputStreamReady) when it is
   * ready for reading.
   */
  _waitForIncoming() {
    if (this._incomingEnabled) {
      let threadManager = Cc["@mozilla.org/thread-manager;1"].getService();
      this._input.asyncWait(this, 0, 0, threadManager.currentThread);
    }
  },

  /**
   * Pause this transport's attempts to read from the input stream.
   * This is used when we've temporarily handed off our input stream for
   * reading bulk data.
   */
  pauseIncoming() {
    this._incomingEnabled = false;
  },

  /**
   * Resume this transport's attempts to read from the input stream.
   */
  resumeIncoming() {
    this._incomingEnabled = true;
    this._flushIncoming();
    this._waitForIncoming();
  },

  // nsIInputStreamCallback
  /**
   * Called when the stream is either readable or closed.
   */
  onInputStreamReady(stream) {
    try {
      while (stream.available() && this._incomingEnabled &&
             this._processIncoming(stream, stream.available())) {
         // Loop until there is nothing more to process
      }
      this._waitForIncoming();
    } catch (e) {
      if (e.result != Cr.NS_BASE_STREAM_WOULD_BLOCK) {
        this.close(e.result);
      } else {
        throw e;
      }
    }
  },

  /**
   * Process the incoming data.  Will create a new currently incoming
   * Packet if needed.  Tells the incoming Packet to read as much data
   * as it can, but reading may not complete.  The Packet signals that
   * its data is ready for delivery by calling one of this transport's
   * _on*Ready methods (see ./packets.js and the _on*Ready methods below).
   *
   * @return {boolean}
   *     Whether incoming stream processing should continue for any
   *     remaining data.
   */
  _processIncoming(stream, count) {
    dumpv("Data available: " + count);

    if (!count) {
      dumpv("Nothing to read, skipping");
      return false;
    }

    try {
      if (!this._incoming) {
        dumpv("Creating a new packet from incoming");

        if (!this._readHeader(stream)) {
          // Not enough data to read packet type
          return false;
        }

        // Attempt to create a new Packet by trying to parse each possible
        // header pattern.
        this._incoming = Packet.fromHeader(this._incomingHeader, this);
        if (!this._incoming) {
          throw new Error("No packet types for header: " +
                        this._incomingHeader);
        }
      }

      if (!this._incoming.done) {
        // We have an incomplete packet, keep reading it.
        dumpv("Existing packet incomplete, keep reading");
        this._incoming.read(stream, this._scriptableInput);
      }
    } catch (e) {
      dump(`Error reading incoming packet: (${e} - ${e.stack})\n`);

      // Now in an invalid state, shut down the transport.
      this.close();
      return false;
    }

    if (!this._incoming.done) {
      // Still not complete, we'll wait for more data.
      dumpv("Packet not done, wait for more");
      return true;
    }

    // Ready for next packet
    this._flushIncoming();
    return true;
  },

  /**
   * Read as far as we can into the incoming data, attempting to build
   * up a complete packet header (which terminates with ":").  We'll only
   * read up to PACKET_HEADER_MAX characters.
   *
   * @return {boolean}
   *     True if we now have a complete header.
   */
  _readHeader() {
    let amountToRead = PACKET_HEADER_MAX - this._incomingHeader.length;
    this._incomingHeader +=
    StreamUtils.delimitedRead(this._scriptableInput, ":", amountToRead);
    if (flags.wantVerbose) {
      dumpv("Header read: " + this._incomingHeader);
    }

    if (this._incomingHeader.endsWith(":")) {
      if (flags.wantVerbose) {
        dumpv("Found packet header successfully: " + this._incomingHeader);
      }
      return true;
    }

    if (this._incomingHeader.length >= PACKET_HEADER_MAX) {
      throw new Error("Failed to parse packet header!");
    }

    // Not enough data yet.
    return false;
  },

  /**
   * If the incoming packet is done, log it as needed and clear the buffer.
   */
  _flushIncoming() {
    if (!this._incoming.done) {
      return;
    }
    if (flags.wantLogging) {
      dumpv("Got: " + this._incoming);
    }
    this._destroyIncoming();
  },

  /**
   * Handler triggered by an incoming JSONPacket completing it's |read|
   * method.  Delivers the packet to this.hooks.onPacket.
   */
  _onJSONObjectReady(object) {
    executeSoon(() => {
    // Ensure the transport is still alive by the time this runs.
      if (this.active) {
        this.emit("packet", object);
        this.hooks.onPacket(object);
      }
    });
  },

  /**
   * Handler triggered by an incoming BulkPacket entering the |read|
   * phase for the stream portion of the packet.  Delivers info about the
   * incoming streaming data to this.hooks.onBulkPacket.  See the main
   * comment on the transport at the top of this file for more details.
   */
  _onBulkReadReady(...args) {
    executeSoon(() => {
    // Ensure the transport is still alive by the time this runs.
      if (this.active) {
        this.emit("bulkpacket", ...args);
        this.hooks.onBulkPacket(...args);
      }
    });
  },

  /**
   * Remove all handlers and references related to the current incoming
   * packet, either because it is now complete or because the transport
   * is closing.
   */
  _destroyIncoming() {
    if (this._incoming) {
      this._incoming.destroy();
    }
    this._incomingHeader = "";
    this._incoming = null;
  },
};

/**
 * An adapter that handles data transfers between the debugger client
 * and server when they both run in the same process. It presents the
 * same API as DebuggerTransport, but instead of transmitting serialized
 * messages across a connection it merely calls the packet dispatcher of
 * the other side.
 *
 * @param {LocalDebuggerTransport} other
 *     The other endpoint for this debugger connection.
 *
 * @see {DebuggerTransport}
 */
function LocalDebuggerTransport(other) {
  EventEmitter.decorate(this);

  this.other = other;
  this.hooks = null;

  // A packet number, shared between this and this.other. This isn't
  // used by the protocol at all, but it makes the packet traces a lot
  // easier to follow.
  this._serial = this.other ? this.other._serial : {count: 0};
  this.close = this.close.bind(this);
}

LocalDebuggerTransport.prototype = {
  /**
   * Transmit a message by directly calling the onPacket handler of the other
   * endpoint.
   */
  send(packet) {
    this.emit("send", packet);

    let serial = this._serial.count++;
    if (flags.wantLogging) {
      // Check 'from' first, as 'echo' packets have both.
      if (packet.from) {
        dumpv("Packet " + serial + " sent from " + uneval(packet.from));
      } else if (packet.to) {
        dumpv("Packet " + serial + " sent to " + uneval(packet.to));
      }
    }
    this._deepFreeze(packet);
    let other = this.other;
    if (other) {
      executeSoon(() => {
        // Avoid the cost of JSON.stringify() when logging is disabled.
        if (flags.wantLogging) {
          dumpv(`Received packet ${serial}: ` +
              JSON.stringify(packet, null, 2));
        }
        if (other.hooks) {
          other.emit("packet", packet);
          other.hooks.onPacket(packet);
        }
      });
    }
  },

  /**
   * Send a streaming bulk packet directly to the onBulkPacket handler
   * of the other endpoint.
   *
   * This case is much simpler than the full DebuggerTransport, since
   * there is no primary stream we have to worry about managing while
   * we hand it off to others temporarily.  Instead, we can just make a
   * single use pipe and be done with it.
   */
  startBulkSend({actor, type, length}) {
    this.emit("startbulksend", {actor, type, length});

    let serial = this._serial.count++;

    dumpv("Sent bulk packet " + serial + " for actor " + actor);
    if (!this.other) {
      let error = new Error("startBulkSend: other side of transport missing");
      return Promise.reject(error);
    }

    let pipe = new Pipe(true, true, 0, 0, null);

    executeSoon(() => {
      dumpv("Received bulk packet " + serial);
      if (!this.other.hooks) {
        return;
      }

      // Receiver
      let deferred = defer();
      let packet = {
        actor,
        type,
        length,
        copyTo: (output) => {
          let copying =
          StreamUtils.copyStream(pipe.inputStream, output, length);
          deferred.resolve(copying);
          return copying;
        },
        stream: pipe.inputStream,
        done: deferred,
      };

      this.other.emit("bulkpacket", packet);
      this.other.hooks.onBulkPacket(packet);

      // Await the result of reading from the stream
      deferred.promise.then(() => pipe.inputStream.close(), this.close);
    });

    // Sender
    let sendDeferred = defer();

    // The remote transport is not capable of resolving immediately here,
    // so we shouldn't be able to either.
    executeSoon(() => {
      let copyDeferred = defer();

      sendDeferred.resolve({
        copyFrom: (input) => {
          let copying =
          StreamUtils.copyStream(input, pipe.outputStream, length);
          copyDeferred.resolve(copying);
          return copying;
        },
        stream: pipe.outputStream,
        done: copyDeferred,
      });

      // Await the result of writing to the stream
      copyDeferred.promise.then(() => pipe.outputStream.close(), this.close);
    });

    return sendDeferred.promise;
  },

  /**
   * Close the transport.
   */
  close() {
    this.emit("close");

    if (this.other) {
      // Remove the reference to the other endpoint before calling close(), to
      // avoid infinite recursion.
      let other = this.other;
      this.other = null;
      other.close();
    }
    if (this.hooks) {
      try {
        this.hooks.onClosed();
      } catch (ex) {
        console.error(ex);
      }
      this.hooks = null;
    }
  },

  /**
   * An empty method for emulating the DebuggerTransport API.
   */
  ready() {},

  /**
   * Helper function that makes an object fully immutable.
   */
  _deepFreeze(object) {
    Object.freeze(object);
    for (let prop in object) {
      // Freeze the properties that are objects, not on the prototype,
      // and not already frozen.  Note that this might leave an unfrozen
      // reference somewhere in the object if there is an already frozen
      // object containing an unfrozen object.
      if (object.hasOwnProperty(prop) && typeof object === "object" &&
          !Object.isFrozen(object)) {
        this._deepFreeze(object[prop]);
      }
    }
  },
};

/**
 * A transport for the debugging protocol that uses nsIMessageManagers to
 * exchange packets with servers running in child processes.
 *
 * In the parent process, <var>mm</var> should be the nsIMessageSender
 * for the child process. In a child process, |mm| should be the child
 * process message manager, which sends packets to the parent.
 *
 * <var>prefix</var> is a string included in the message names, to
 * distinguish multiple servers running in the same child process.
 *
 * This transport exchanges messages named <tt>debug:PREFIX:packet</tt>,
 * where <tt>PREFIX</tt> is <var>prefix</var>, whose data is the protocol
 * packet.
 */
function ChildDebuggerTransport(mm, prefix) {
  EventEmitter.decorate(this);

  this._mm = mm;
  this._messageName = "debug:" + prefix + ":packet";
}

/*
 * To avoid confusion, we use 'message' to mean something that
 * nsIMessageSender conveys, and 'packet' to mean a remote debugging
 * protocol packet.
 */
ChildDebuggerTransport.prototype = {
  constructor: ChildDebuggerTransport,

  hooks: null,

  _addListener() {
    this._mm.addMessageListener(this._messageName, this);
  },

  _removeListener() {
    try {
      this._mm.removeMessageListener(this._messageName, this);
    } catch (e) {
      if (e.result != Cr.NS_ERROR_NULL_POINTER) {
        throw e;
      }
      // In some cases, especially when using messageManagers in non-e10s
      // mode, we reach this point with a dead messageManager which only
      // throws errors but does not seem to indicate in any other way that
      // it is dead.
    }
  },

  ready() {
    this._addListener();
  },

  close() {
    this._removeListener();
    this.emit("close");
    this.hooks.onClosed();
  },

  receiveMessage({data}) {
    this.emit("packet", data);
    this.hooks.onPacket(data);
  },

  send(packet) {
    this.emit("send", packet);
    try {
      this._mm.sendAsyncMessage(this._messageName, packet);
    } catch (e) {
      if (e.result != Cr.NS_ERROR_NULL_POINTER) {
        throw e;
      }
      // In some cases, especially when using messageManagers in non-e10s
      // mode, we reach this point with a dead messageManager which only
      // throws errors but does not seem to indicate in any other way that
      // it is dead.
    }
  },

  startBulkSend() {
    throw new Error("Can't send bulk data to child processes.");
  },

  swapBrowser(mm) {
    this._removeListener();
    this._mm = mm;
    this._addListener();
  },
};

// WorkerDebuggerTransport is defined differently depending on whether we are
// on the main thread or a worker thread. In the former case, we are required
// by the devtools loader, and isWorker will be false. Otherwise, we are
// required by the worker loader, and isWorker will be true.
//
// Each worker debugger supports only a single connection to the main thread.
// However, its theoretically possible for multiple servers to connect to the
// same worker. Consequently, each transport has a connection id, to allow
// messages from multiple connections to be multiplexed on a single channel.

if (!this.isWorker) {
  // Main thread
  (function() {
    /**
     * A transport that uses a WorkerDebugger to send packets from the main
     * thread to a worker thread.
     */
    function WorkerDebuggerTransport(dbg, id) {
      this._dbg = dbg;
      this._id = id;
      this.onMessage = this._onMessage.bind(this);
    }

    WorkerDebuggerTransport.prototype = {
      constructor: WorkerDebuggerTransport,

      ready() {
        this._dbg.addListener(this);
      },

      close() {
        this._dbg.removeListener(this);
        if (this.hooks) {
          this.hooks.onClosed();
        }
      },

      send(packet) {
        this._dbg.postMessage(JSON.stringify({
          type: "message",
          id: this._id,
          message: packet,
        }));
      },

      startBulkSend() {
        throw new Error("Can't send bulk data from worker threads!");
      },

      _onMessage(message) {
        let packet = JSON.parse(message);
        if (packet.type !== "message" || packet.id !== this._id) {
          return;
        }

        if (this.hooks) {
          this.hooks.onPacket(packet.message);
        }
      },
    };

  }).call(this);
} else {
  // Worker thread
  (function() {
    /**
     * A transport that uses a WorkerDebuggerGlobalScope to send packets
     * from a worker thread to the main thread.
     */
    function WorkerDebuggerTransport(scope, id) {
      this._scope = scope;
      this._id = id;
      this._onMessage = this._onMessage.bind(this);
    }

    WorkerDebuggerTransport.prototype = {
      constructor: WorkerDebuggerTransport,

      ready() {
        this._scope.addEventListener("message", this._onMessage);
      },

      close() {
        this._scope.removeEventListener("message", this._onMessage);
        if (this.hooks) {
          this.hooks.onClosed();
        }
      },

      send(packet) {
        this._scope.postMessage(JSON.stringify({
          type: "message",
          id: this._id,
          message: packet,
        }));
      },

      startBulkSend() {
        throw new Error("Can't send bulk data from worker threads!");
      },

      _onMessage(event) {
        let packet = JSON.parse(event.data);
        if (packet.type !== "message" || packet.id !== this._id) {
          return;
        }

        if (this.hooks) {
          this.hooks.onPacket(packet.message);
        }
      },
    };

  }).call(this);
}
