gecko/toolkit/devtools/server/transport.js

354 lines
11 KiB
JavaScript

/* -*- Mode: javascript; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ft=javascript ts=2 et sw=2 tw=80: */
/* 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";
Components.utils.import("resource://gre/modules/NetUtil.jsm");
let wantLogging = Services.prefs.getBoolPref("devtools.debugger.log");
/**
* 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 aInput nsIInputStream
* The input stream.
* @param aOutput 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() to send packets as you please, and handle incoming
* packets passed to hook.onPacket.
* 4) Call dt.close() to close the connection, and disengage from the event
* loop.
*
* A packet handler is an object with two 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.
*
* - onClosed(status) - called when the connection is closed. |Status| is
* an nsresult, of the sort passed to nsIRequestObserver.
*
* 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.
*/
this.DebuggerTransport = function DebuggerTransport(aInput, aOutput)
{
this._input = aInput;
this._output = aOutput;
this._converter = Cc["@mozilla.org/intl/scriptableunicodeconverter"]
.createInstance(Ci.nsIScriptableUnicodeConverter);
this._converter.charset = "UTF-8";
this._outgoing = "";
this._incoming = "";
this.hooks = null;
}
DebuggerTransport.prototype = {
/**
* Transmit a 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 DT_send(aPacket) {
let data = JSON.stringify(aPacket);
data = this._converter.ConvertFromUnicode(data);
data = data.length + ':' + data;
this._outgoing += data;
this._flushOutgoing();
},
/**
* Close the transport.
*/
close: function DT_close() {
this._input.close();
this._output.close();
},
/**
* Flush the outgoing stream.
*/
_flushOutgoing: function DT_flushOutgoing() {
if (this._outgoing.length > 0) {
var threadManager = Cc["@mozilla.org/thread-manager;1"].getService();
this._output.asyncWait(this, 0, 0, threadManager.currentThread);
}
},
onOutputStreamReady:
makeInfallible(function DT_onOutputStreamReady(aStream) {
let written = 0;
try {
written = aStream.write(this._outgoing, this._outgoing.length);
} catch(e if e.result == Components.results.NS_BASE_STREAM_CLOSED) {
dumpn("Connection closed.");
this.close();
return;
}
this._outgoing = this._outgoing.slice(written);
this._flushOutgoing();
}, "DebuggerTransport.prototype.onOutputStreamReady"),
/**
* Initialize the input stream for reading. Once this method has been
* called, we watch for packets on the input stream, and pass them to
* this.hook.onPacket.
*/
ready: function DT_ready() {
let pump = Cc["@mozilla.org/network/input-stream-pump;1"]
.createInstance(Ci.nsIInputStreamPump);
pump.init(this._input, -1, -1, 0, 0, false);
pump.asyncRead(this, null);
},
// nsIStreamListener
onStartRequest:
makeInfallible(function DT_onStartRequest(aRequest, aContext) {},
"DebuggerTransport.prototype.onStartRequest"),
onStopRequest:
makeInfallible(function DT_onStopRequest(aRequest, aContext, aStatus) {
this.close();
if (this.hooks) {
this.hooks.onClosed(aStatus);
this.hooks = null;
}
}, "DebuggerTransport.prototype.onStopRequest"),
onDataAvailable:
makeInfallible(function DT_onDataAvailable(aRequest, aContext,
aStream, aOffset, aCount) {
this._incoming += NetUtil.readInputStreamToString(aStream,
aStream.available());
while (this._processIncoming()) {};
}, "DebuggerTransport.prototype.onDataAvailable"),
/**
* Process incoming packets. Returns true if a packet has been received, either
* if it was properly parsed or not. Returns false if the incoming stream does
* not contain a full packet yet. After a proper packet is parsed, the dispatch
* handler DebuggerTransport.hooks.onPacket is called with the packet as a
* parameter.
*/
_processIncoming: function DT__processIncoming() {
// Well this is ugly.
let sep = this._incoming.indexOf(':');
if (sep < 0) {
// Incoming packet length is too big anyway - drop the connection.
if (this._incoming.length > 20) {
this.close();
}
return false;
}
let count = this._incoming.substring(0, sep);
// Check for a positive number with no garbage afterwards.
if (!/^[0-9]+$/.exec(count)) {
this.close();
return false;
}
count = +count;
if (this._incoming.length - (sep + 1) < count) {
// Don't have a complete request yet.
return false;
}
// We have a complete request, pluck it out of the data and parse it.
this._incoming = this._incoming.substring(sep + 1);
let packet = this._incoming.substring(0, count);
this._incoming = this._incoming.substring(count);
try {
packet = this._converter.ConvertToUnicode(packet);
var parsed = JSON.parse(packet);
} catch(e) {
let msg = "Error parsing incoming packet: " + packet + " (" + e + " - " + e.stack + ")";
if (Cu.reportError) {
Cu.reportError(msg);
}
dump(msg + "\n");
return true;
}
if (wantLogging) {
dumpn("Got: " + JSON.stringify(parsed, null, 2));
}
let self = this;
Services.tm.currentThread.dispatch(makeInfallible(function() {
// Ensure the hooks are still around by the time this runs (they will go
// away when the transport is closed).
if (self.hooks) {
self.hooks.onPacket(parsed);
}
}, "DebuggerTransport instance's this.hooks.onPacket"), 0);
return true;
}
}
/**
* 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 aOther LocalDebuggerTransport
* The other endpoint for this debugger connection.
*
* @see DebuggerTransport
*/
this.LocalDebuggerTransport = function LocalDebuggerTransport(aOther)
{
this.other = aOther;
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 };
}
LocalDebuggerTransport.prototype = {
/**
* Transmit a message by directly calling the onPacket handler of the other
* endpoint.
*/
send: function LDT_send(aPacket) {
let serial = this._serial.count++;
if (wantLogging) {
/* Check 'from' first, as 'echo' packets have both. */
if (aPacket.from) {
dumpn("Packet " + serial + " sent from " + uneval(aPacket.from));
} else if (aPacket.to) {
dumpn("Packet " + serial + " sent to " + uneval(aPacket.to));
}
}
this._deepFreeze(aPacket);
let other = this.other;
if (other) {
Services.tm.currentThread.dispatch(makeInfallible(function() {
// Avoid the cost of JSON.stringify() when logging is disabled.
if (wantLogging) {
dumpn("Received packet " + serial + ": " + JSON.stringify(aPacket, null, 2));
}
if (other.hooks) {
other.hooks.onPacket(aPacket);
}
}, "LocalDebuggerTransport instance's this.other.hooks.onPacket"), 0);
}
},
/**
* Close the transport.
*/
close: function LDT_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) {
Components.utils.reportError(ex);
}
this.hooks = null;
}
},
/**
* An empty method for emulating the DebuggerTransport API.
*/
ready: function LDT_ready() {},
/**
* Helper function that makes an object fully immutable.
*/
_deepFreeze: function LDT_deepFreeze(aObject) {
Object.freeze(aObject);
for (let prop in aObject) {
// 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 (aObject.hasOwnProperty(prop) && typeof aObject === "object" &&
!Object.isFrozen(aObject)) {
this._deepFreeze(o[prop]);
}
}
}
};
/**
* A transport for the debugging protocol that uses nsIMessageSenders to
* exchange packets with servers running in child processes.
*
* In the parent process, |aSender| should be the nsIMessageSender for the
* child process. In a child process, |aSender| should be the child process
* message manager, which sends packets to the parent.
*
* aPrefix 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 |aPrefix|, whose data is the protocol packet.
*/
function ChildDebuggerTransport(aSender, aPrefix) {
this._sender = aSender.QueryInterface(Components.interfaces.nsIMessageSender);
this._messageName = "debug:" + aPrefix + ":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,
ready: function () {
this._sender.addMessageListener(this._messageName, this);
},
close: function () {
this._sender.removeMessageListener(this._messageName, this);
this.hooks.onClosed();
},
receiveMessage: function ({data}) {
this.hooks.onPacket(data);
},
send: function (packet) {
this._sender.sendAsyncMessage(this._messageName, packet);
}
};