/* 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";
/**
* Packets contain read / write functionality for the different packet types
* supported by the debugging protocol, so that a transport can focus on
* delivery and queue management without worrying too much about the specific
* packet types.
*
* They are intended to be "one use only", so a new packet should be
* instantiated for each incoming or outgoing packet.
*
* A complete Packet type should expose at least the following:
* * read(stream, scriptableStream)
* Called when the input stream has data to read
* * write(stream)
* Called when the output stream is ready to write
* * get done()
* Returns true once the packet is done being read / written
* * destroy()
* Called to clean up at the end of use
*/
const {classes: Cc, interfaces: Ci, utils: Cu} = Components;
const {StreamUtils} =
Cu.import("chrome://marionette/content/stream-utils.js", {});
const unicodeConverter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
.createInstance(Ci.nsIScriptableUnicodeConverter);
unicodeConverter.charset = "UTF-8";
const defer = function() {
let deferred = {
promise: new Promise((resolve, reject) => {
deferred.resolve = resolve;
deferred.reject = reject;
}),
};
return deferred;
};
this.EXPORTED_SYMBOLS = ["RawPacket", "Packet", "JSONPacket", "BulkPacket"];
// The transport's previous check ensured the header length did not
// exceed 20 characters. Here, we opt for the somewhat smaller, but still
// large limit of 1 TiB.
const PACKET_LENGTH_MAX = Math.pow(2, 40);
/**
* A generic Packet processing object (extended by two subtypes below).
*
* @class
*/
function Packet(transport) {
this._transport = transport;
this._length = 0;
}
/**
* Attempt to initialize a new Packet based on the incoming packet header
* we've received so far. We try each of the types in succession, trying
* JSON packets first since they are much more common.
*
* @param {string} header
* Packet header string to attempt parsing.
* @param {DebuggerTransport} transport
* Transport instance that will own the packet.
*
* @return {Packet}
* Parsed packet of the matching type, or null if no types matched.
*/
Packet.fromHeader = function(header, transport) {
return JSONPacket.fromHeader(header, transport) ||
BulkPacket.fromHeader(header, transport);
};
Packet.prototype = {
get length() {
return this._length;
},
set length(length) {
if (length > PACKET_LENGTH_MAX) {
throw new Error("Packet length " + length +
" exceeds the max length of " + PACKET_LENGTH_MAX);
}
this._length = length;
},
destroy() {
this._transport = null;
},
};
/**
* With a JSON packet (the typical packet type sent via the transport),
* data is transferred as a JSON packet serialized into a string,
* with the string length prepended to the packet, followed by a colon
* ([length]:[packet]). The contents of the JSON packet are specified in
* the Remote Debugging Protocol specification.
*
* @param {DebuggerTransport} transport
* Transport instance that will own the packet.
*/
function JSONPacket(transport) {
Packet.call(this, transport);
this._data = "";
this._done = false;
}
/**
* Attempt to initialize a new JSONPacket based on the incoming packet
* header we've received so far.
*
* @param {string} header
* Packet header string to attempt parsing.
* @param {DebuggerTransport} transport
* Transport instance that will own the packet.
*
* @return {JSONPacket}
* Parsed packet, or null if it's not a match.
*/
JSONPacket.fromHeader = function(header, transport) {
let match = this.HEADER_PATTERN.exec(header);
if (!match) {
return null;
}
let packet = new JSONPacket(transport);
packet.length = +match[1];
return packet;
};
JSONPacket.HEADER_PATTERN = /^(\d+):$/;
JSONPacket.prototype = Object.create(Packet.prototype);
Object.defineProperty(JSONPacket.prototype, "object", {
/**
* Gets the object (not the serialized string) being read or written.
*/
get() {
return this._object;
},
/**
* Sets the object to be sent when write() is called.
*/
set(object) {
this._object = object;
let data = JSON.stringify(object);
this._data = unicodeConverter.ConvertFromUnicode(data);
this.length = this._data.length;
},
});
JSONPacket.prototype.read = function(stream, scriptableStream) {
// Read in more packet data.
this._readData(stream, scriptableStream);
if (!this.done) {
// Don't have a complete packet yet.
return;
}
let json = this._data;
try {
json = unicodeConverter.ConvertToUnicode(json);
this._object = JSON.parse(json);
} catch (e) {
let msg = "Error parsing incoming packet: " + json + " (" + e +
" - " + e.stack + ")";
console.error(msg);
dump(msg + "\n");
return;
}
this._transport._onJSONObjectReady(this._object);
};
JSONPacket.prototype._readData = function(stream, scriptableStream) {
let bytesToRead = Math.min(
this.length - this._data.length,
stream.available());
this._data += scriptableStream.readBytes(bytesToRead);
this._done = this._data.length === this.length;
};
JSONPacket.prototype.write = function(stream) {
if (this._outgoing === undefined) {
// Format the serialized packet to a buffer
this._outgoing = this.length + ":" + this._data;
}
let written = stream.write(this._outgoing, this._outgoing.length);
this._outgoing = this._outgoing.slice(written);
this._done = !this._outgoing.length;
};
Object.defineProperty(JSONPacket.prototype, "done", {
get() {
return this._done;
},
});
JSONPacket.prototype.toString = function() {
return JSON.stringify(this._object, null, 2);
};
/**
* With a bulk packet, data is transferred by temporarily handing over
* the transport's input or output stream to the application layer for
* writing data directly. This can be much faster for large data sets,
* and avoids various stages of copies and data duplication inherent in
* the JSON packet type. The bulk packet looks like:
*
* bulk [actor] [type] [length]:[data]
*
* The interpretation of the data portion depends on the kind of actor and
* the packet's type. See the Remote Debugging Protocol Stream Transport
* spec for more details.
*
* @param {DebuggerTransport} transport
* Transport instance that will own the packet.
*/
function BulkPacket(transport) {
Packet.call(this, transport);
this._done = false;
this._readyForWriting = defer();
}
/**
* Attempt to initialize a new BulkPacket based on the incoming packet
* header we've received so far.
*
* @param {string} header
* Packet header string to attempt parsing.
* @param {DebuggerTransport} transport
* Transport instance that will own the packet.
*
* @return {BulkPacket}
* Parsed packet, or null if it's not a match.
*/
BulkPacket.fromHeader = function(header, transport) {
let match = this.HEADER_PATTERN.exec(header);
if (!match) {
return null;
}
let packet = new BulkPacket(transport);
packet.header = {
actor: match[1],
type: match[2],
length: +match[3],
};
return packet;
};
BulkPacket.HEADER_PATTERN = /^bulk ([^: ]+) ([^: ]+) (\d+):$/;
BulkPacket.prototype = Object.create(Packet.prototype);
BulkPacket.prototype.read = function(stream) {
// Temporarily pause monitoring of the input stream
this._transport.pauseIncoming();
let deferred = defer();
this._transport._onBulkReadReady({
actor: this.actor,
type: this.type,
length: this.length,
copyTo: (output) => {
let copying = StreamUtils.copyStream(stream, output, this.length);
deferred.resolve(copying);
return copying;
},
stream,
done: deferred,
});
// Await the result of reading from the stream
deferred.promise.then(() => {
this._done = true;
this._transport.resumeIncoming();
}, this._transport.close);
// Ensure this is only done once
this.read = () => {
throw new Error("Tried to read() a BulkPacket's stream multiple times.");
};
};
BulkPacket.prototype.write = function(stream) {
if (this._outgoingHeader === undefined) {
// Format the serialized packet header to a buffer
this._outgoingHeader = "bulk " + this.actor + " " + this.type + " " +
this.length + ":";
}
// Write the header, or whatever's left of it to write.
if (this._outgoingHeader.length) {
let written = stream.write(this._outgoingHeader,
this._outgoingHeader.length);
this._outgoingHeader = this._outgoingHeader.slice(written);
return;
}
// Temporarily pause the monitoring of the output stream
this._transport.pauseOutgoing();
let deferred = defer();
this._readyForWriting.resolve({
copyFrom: (input) => {
let copying = StreamUtils.copyStream(input, stream, this.length);
deferred.resolve(copying);
return copying;
},
stream,
done: deferred,
});
// Await the result of writing to the stream
deferred.promise.then(() => {
this._done = true;
this._transport.resumeOutgoing();
}, this._transport.close);
// Ensure this is only done once
this.write = () => {
throw new Error("Tried to write() a BulkPacket's stream multiple times.");
};
};
Object.defineProperty(BulkPacket.prototype, "streamReadyForWriting", {
get() {
return this._readyForWriting.promise;
},
});
Object.defineProperty(BulkPacket.prototype, "header", {
get() {
return {
actor: this.actor,
type: this.type,
length: this.length,
};
},
set(header) {
this.actor = header.actor;
this.type = header.type;
this.length = header.length;
},
});
Object.defineProperty(BulkPacket.prototype, "done", {
get() {
return this._done;
},
});
BulkPacket.prototype.toString = function() {
return "Bulk: " + JSON.stringify(this.header, null, 2);
};
/**
* RawPacket is used to test the transport's error handling of malformed
* packets, by writing data directly onto the stream.
* @param transport DebuggerTransport
* The transport instance that will own the packet.
* @param data string
* The raw string to send out onto the stream.
*/
function RawPacket(transport, data) {
Packet.call(this, transport);
this._data = data;
this.length = data.length;
this._done = false;
}
RawPacket.prototype = Object.create(Packet.prototype);
RawPacket.prototype.read = function() {
// this has not yet been needed for testing
throw new Error("Not implemented");
};
RawPacket.prototype.write = function(stream) {
let written = stream.write(this._data, this._data.length);
this._data = this._data.slice(written);
this._done = !this._data.length;
};
Object.defineProperty(RawPacket.prototype, "done", {
get() {
return this._done;
},
});