tor-browser

transport.sys.mjs (16600B)

---

/* 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/. */

const lazy = {};

ChromeUtils.defineESModuleGetters(lazy, {
 EventEmitter: "resource://gre/modules/EventEmitter.sys.mjs",

 BulkPacket: "chrome://remote/content/marionette/packets.sys.mjs",
 executeSoon: "chrome://remote/content/shared/Sync.sys.mjs",
 JSONPacket: "chrome://remote/content/marionette/packets.sys.mjs",
 Packet: "chrome://remote/content/marionette/packets.sys.mjs",
 StreamUtils: "chrome://remote/content/marionette/stream-utils.sys.mjs",
});

ChromeUtils.defineLazyGetter(lazy, "ScriptableInputStream", () => {
 return Components.Constructor(
   "@mozilla.org/scriptableinputstream;1",
   "nsIScriptableInputStream",
   "init"
 );
});

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

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

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:
*
*             - params
*                {nsIAsyncOutputStream} output
*                  The stream to copy to.
*             - returns {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
*/
export function DebuggerTransport(input, output) {
 lazy.EventEmitter.decorate(this);

 this._input = input;
 this._scriptableInput = new lazy.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 lazy.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
  *
  * @returns {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:
  *
  *                   - params
  *                     {nsIAsyncInputStream} input
  *                       The stream to copy from.
  *                   - returns {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 lazy.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) {
     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).
  *
  * @returns {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 = lazy.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.
  *
  * @returns {boolean}
  *     True if we now have a complete header.
  */
 _readHeader() {
   let amountToRead = PACKET_HEADER_MAX - this._incomingHeader.length;
   this._incomingHeader += lazy.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) {
   lazy.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) {
   lazy.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;
 },
};