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/* 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
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
});
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;
},
};