gecko-dev/devtools/shared/transport/transport.js

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JavaScript

/* 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 */
// TODO: Get rid of this code once the marionette server loads transport.js as
// an SDK module (see bug 1000814)
(function (factory) {
if (this.module && module.id.indexOf("transport") >= 0) {
// require
factory.call(this, require, exports);
} else if (this.require) {
// loadSubScript
factory.call(this, require, this);
} else {
// Cu.import
const Cu = Components.utils;
const { require } = Cu.import("resource://devtools/shared/Loader.jsm", {});
factory.call(this, require, this);
}
}).call(this, function (require, exports) {
const { Cc, Cr, CC } = require("chrome");
const DevToolsUtils = require("devtools/shared/DevToolsUtils");
const { dumpn, dumpv } = DevToolsUtils;
const flags = require("devtools/shared/flags");
const StreamUtils = require("devtools/shared/transport/stream-utils");
const { Packet, JSONPacket, BulkPacket } =
require("devtools/shared/transport/packets");
const promise = require("promise");
const defer = require("devtools/shared/defer");
const EventEmitter = require("devtools/shared/event-emitter");
DevToolsUtils.defineLazyGetter(this, "Pipe", () => {
return CC("@mozilla.org/pipe;1", "nsIPipe", "init");
});
DevToolsUtils.defineLazyGetter(this, "ScriptableInputStream", () => {
return CC("@mozilla.org/scriptableinputstream;1",
"nsIScriptableInputStream", "init");
});
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 input nsIAsyncInputStream
* The input stream.
* @param output nsIAsyncOutputStream
* 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 |dumpn|.
* 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 output nsIAsyncOutputStream
* 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.
*/
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: function (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 header Object
* 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 |dumpn|. 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 input nsIAsyncInputStream
* 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 chunk
* that is copied. See stream-utils.js.
*/
startBulkSend: function (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 reason nsresult / object (optional)
* The status code or error message that corresponds to the reason for
* closing the transport (likely because a stream closed or failed).
*/
close: function (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) {
dumpn("Transport closed: " + DevToolsUtils.safeErrorString(reason));
} else {
dumpn("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: function () {
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: function () {
this._outgoingEnabled = false;
},
/**
* Resume this transport's attempts to write to the output stream.
*/
resumeOutgoing: function () {
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: DevToolsUtils.makeInfallible(function (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();
}, "DebuggerTransport.prototype.onOutputStreamReady"),
/**
* Remove the current outgoing packet from the queue upon completion.
*/
_finishCurrentOutgoing: function () {
if (this._currentOutgoing) {
this._currentOutgoing.destroy();
this._outgoing.shift();
}
},
/**
* Clear the entire outgoing queue.
*/
_destroyAllOutgoing: function () {
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: function () {
this.active = true;
this._waitForIncoming();
},
/**
* Asks the input stream to notify us (via onInputStreamReady) when it is
* ready for reading.
*/
_waitForIncoming: function () {
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: function () {
this._incomingEnabled = false;
},
/**
* Resume this transport's attempts to read from the input stream.
*/
resumeIncoming: function () {
this._incomingEnabled = true;
this._flushIncoming();
this._waitForIncoming();
},
// nsIInputStreamCallback
/**
* Called when the stream is either readable or closed.
*/
onInputStreamReady: DevToolsUtils.makeInfallible(function (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;
}
}
}, "DebuggerTransport.prototype.onInputStreamReady"),
/**
* 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: function (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) {
let msg = "Error reading incoming packet: (" + e + " - " + e.stack + ")";
dumpn(msg);
// 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: function () {
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: function () {
if (!this._incoming.done) {
return;
}
if (flags.wantLogging) {
dumpn("Got: " + this._incoming);
}
this._destroyIncoming();
},
/**
* Handler triggered by an incoming JSONPacket completing it's |read| method.
* Delivers the packet to this.hooks.onPacket.
*/
_onJSONObjectReady: function (object) {
DevToolsUtils.executeSoon(DevToolsUtils.makeInfallible(() => {
// Ensure the transport is still alive by the time this runs.
if (this.active) {
this.emit("packet", object);
this.hooks.onPacket(object);
}
}, "DebuggerTransport instance's this.hooks.onPacket"));
},
/**
* 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: function (...args) {
DevToolsUtils.executeSoon(DevToolsUtils.makeInfallible(() => {
// Ensure the transport is still alive by the time this runs.
if (this.active) {
this.emit("bulkpacket", ...args);
this.hooks.onBulkPacket(...args);
}
}, "DebuggerTransport instance's this.hooks.onBulkPacket"));
},
/**
* Remove all handlers and references related to the current incoming packet,
* either because it is now complete or because the transport is closing.
*/
_destroyIncoming: function () {
if (this._incoming) {
this._incoming.destroy();
}
this._incomingHeader = "";
this._incoming = null;
}
};
exports.DebuggerTransport = DebuggerTransport;
/**
* 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 other LocalDebuggerTransport
* 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: function (packet) {
this.emit("send", packet);
let serial = this._serial.count++;
if (flags.wantLogging) {
// Check 'from' first, as 'echo' packets have both.
if (packet.from) {
dumpn("Packet " + serial + " sent from " + uneval(packet.from));
} else if (packet.to) {
dumpn("Packet " + serial + " sent to " + uneval(packet.to));
}
}
this._deepFreeze(packet);
let other = this.other;
if (other) {
DevToolsUtils.executeSoon(DevToolsUtils.makeInfallible(() => {
// Avoid the cost of JSON.stringify() when logging is disabled.
if (flags.wantLogging) {
dumpn("Received packet " + serial + ": " + JSON.stringify(packet, null, 2));
}
if (other.hooks) {
other.emit("packet", packet);
other.hooks.onPacket(packet);
}
}, "LocalDebuggerTransport instance's this.other.hooks.onPacket"));
}
},
/**
* 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: function ({actor, type, length}) {
this.emit("startbulksend", {actor, type, length});
let serial = this._serial.count++;
dumpn("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);
DevToolsUtils.executeSoon(DevToolsUtils.makeInfallible(() => {
dumpn("Received bulk packet " + serial);
if (!this.other.hooks) {
return;
}
// Receiver
let deferred = defer();
let packet = {
actor: actor,
type: type,
length: 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);
}, "LocalDebuggerTransport instance's this.other.hooks.onBulkPacket"));
// Sender
let sendDeferred = defer();
// The remote transport is not capable of resolving immediately here, so we
// shouldn't be able to either.
DevToolsUtils.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: function () {
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: function () {},
/**
* Helper function that makes an object fully immutable.
*/
_deepFreeze: function (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]);
}
}
}
};
exports.LocalDebuggerTransport = LocalDebuggerTransport;
/**
* A transport for the debugging protocol that uses nsIMessageManagers to
* exchange packets with servers running in child processes.
*
* In the parent process, |mm| 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.
*
* |prefix| is a string included in the message names, to distinguish
* multiple servers running in the same child process.
*
* This transport exchanges messages named 'debug:<prefix>:packet', where
* <prefix> is |prefix|, 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: function () {
this._addListener();
},
close: function () {
this._removeListener();
this.emit("close");
this.hooks.onClosed();
},
receiveMessage: function ({data}) {
this.emit("packet", data);
this.hooks.onPacket(data);
},
send: function (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: function () {
throw new Error("Can't send bulk data to child processes.");
},
swapBrowser(mm) {
this._removeListener();
this._mm = mm;
this._addListener();
},
};
exports.ChildDebuggerTransport = ChildDebuggerTransport;
// 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: function () {
this._dbg.addListener(this);
},
close: function () {
this._dbg.removeListener(this);
if (this.hooks) {
this.hooks.onClosed();
}
},
send: function (packet) {
this._dbg.postMessage(JSON.stringify({
type: "message",
id: this._id,
message: packet
}));
},
startBulkSend: function () {
throw new Error("Can't send bulk data from worker threads!");
},
_onMessage: function (message) {
let packet = JSON.parse(message);
if (packet.type !== "message" || packet.id !== this._id) {
return;
}
if (this.hooks) {
this.hooks.onPacket(packet.message);
}
}
};
exports.WorkerDebuggerTransport = WorkerDebuggerTransport;
}).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: function () {
this._scope.addEventListener("message", this._onMessage);
},
close: function () {
this._scope.removeEventListener("message", this._onMessage);
if (this.hooks) {
this.hooks.onClosed();
}
},
send: function (packet) {
this._scope.postMessage(JSON.stringify({
type: "message",
id: this._id,
message: packet
}));
},
startBulkSend: function () {
throw new Error("Can't send bulk data from worker threads!");
},
_onMessage: function (event) {
let packet = JSON.parse(event.data);
if (packet.type !== "message" || packet.id !== this._id) {
return;
}
if (this.hooks) {
this.hooks.onPacket(packet.message);
}
}
};
exports.WorkerDebuggerTransport = WorkerDebuggerTransport;
}).call(this);
}
});