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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
"use strict";
/**
* 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) {
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() {
this._addListener();
},
close(options) {
this._removeListener();
if (this.hooks.onTransportClosed) {
this.hooks.onTransportClosed(null, options);
}
},
receiveMessage({ data }) {
this.hooks.onPacket(data);
},
/**
* Helper method to ensure a given `object` can be sent across message manager
* without being serialized to JSON.
*/
_canBeSerialized(object) {
try {
const holder = new StructuredCloneHolder(
"ChildDebuggerTransport._canBeSerialized",
null,
object
);
holder.deserialize(this);
} catch (e) {
return false;
}
return true;
},
pathToUnserializable(object) {
for (const key in object) {
const value = object[key];
if (!this._canBeSerialized(value)) {
if (typeof value == "object") {
return [key].concat(this.pathToUnserializable(value));
}
return [key];
}
}
return [];
},
send(packet) {
if (flags.testing && !this._canBeSerialized(packet)) {
const attributes = this.pathToUnserializable(packet);
let msg =
"Following packet can't be serialized: " + JSON.stringify(packet);
msg += "\nBecause of attributes: " + attributes.join(", ") + "\n";
msg += "Did you pass a function or an XPCOM object in it?";
throw new Error(msg);
}
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() {
throw new Error("Can't send bulk data to child processes.");
},
};
exports.ChildDebuggerTransport = ChildDebuggerTransport;