Source code
Revision control
Copy as Markdown
Other Tools
/* 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";
loader.lazyRequireGetter(
this,
"MainThreadWorkerDebuggerTransport",
true
);
/**
* Start a DevTools server in a worker and add it as a child server for a given active connection.
*
* @params {DevToolsConnection} connection
* @params {WorkerDebugger} dbg: The WorkerDebugger we want to create a target actor for.
* @params {String} forwardingPrefix: The prefix that will be used to forward messages
* to the DevToolsServer on the worker thread.
* @params {Object} options: An option object that will be passed with the "connect" packet.
* @params {Object} options.sessionData: The sessionData object that will be passed to the
* worker target actor.
*/
function connectToWorker(connection, dbg, forwardingPrefix, options) {
return new Promise((resolve, reject) => {
if (!DevToolsUtils.isWorkerDebuggerAlive(dbg)) {
reject("closed");
return;
}
// Step 1: Ensure the worker debugger is initialized.
if (!dbg.isInitialized) {
// Create a listener for rpc requests from the worker debugger. Only do
// this once, when the worker debugger is first initialized, rather than
// for each connection.
const listener = {
onClose: () => {
dbg.removeListener(listener);
},
onMessage: message => {
message = JSON.parse(message);
if (message.type !== "rpc") {
if (message.type == "session-data-processed") {
// The thread actor has finished processing session data, including breakpoints.
// Allow content to begin executing in the worker and possibly hit early breakpoints.
dbg.setDebuggerReady(true);
}
return;
}
Promise.resolve()
.then(() => {
const method = {
fetch: DevToolsUtils.fetch,
}[message.method];
if (!method) {
throw Error("Unknown method: " + message.method);
}
return method.apply(undefined, message.params);
})
.then(
value => {
dbg.postMessage(
JSON.stringify({
type: "rpc",
result: value,
error: null,
id: message.id,
})
);
},
reason => {
dbg.postMessage(
JSON.stringify({
type: "rpc",
result: null,
error: reason,
id: message.id,
})
);
}
);
},
};
dbg.addListener(listener);
}
if (!DevToolsUtils.isWorkerDebuggerAlive(dbg)) {
reject("closed");
return;
}
// WorkerDebugger.url isn't always an absolute URL.
// Use the related document URL in order to make it absolute.
const absoluteURL = dbg.window?.location?.href
? new URL(dbg.url, dbg.window.location.href).href
: dbg.url;
// Step 2: Send a connect request to the worker debugger.
dbg.postMessage(
JSON.stringify({
type: "connect",
forwardingPrefix,
options,
workerDebuggerData: {
id: dbg.id,
type: dbg.type,
url: absoluteURL,
// We don't have access to Services.prefs in Worker thread, so pass its value
// from here.
workerConsoleApiMessagesDispatchedToMainThread:
Services.prefs.getBoolPref(
"dom.worker.console.dispatch_events_to_main_thread"
),
},
})
);
// Steps 3-5 are performed on the worker thread (see worker.js).
// Step 6: Wait for a connection response from the worker debugger.
const listener = {
onClose: () => {
dbg.removeListener(listener);
reject("closed");
},
onMessage: message => {
message = JSON.parse(message);
if (
message.type !== "connected" ||
message.forwardingPrefix !== forwardingPrefix
) {
return;
}
// The initial connection message has been received, don't
// need to listen any longer
dbg.removeListener(listener);
// Step 7: Create a transport for the connection to the worker.
const transport = new MainThreadWorkerDebuggerTransport(
dbg,
forwardingPrefix
);
transport.ready();
transport.hooks = {
onTransportClosed: () => {
if (DevToolsUtils.isWorkerDebuggerAlive(dbg)) {
// If the worker happens to be shutting down while we are trying
// to close the connection, there is a small interval during
// which no more runnables can be dispatched to the worker, but
// the worker debugger has not yet been closed. In that case,
// the call to postMessage below will fail. The onTransportClosed hook on
// DebuggerTransport is not supposed to throw exceptions, so we
// need to make sure to catch these early.
try {
dbg.postMessage(
JSON.stringify({
type: "disconnect",
forwardingPrefix,
})
);
} catch (e) {
// We can safely ignore these exceptions. The only time the
// call to postMessage can fail is if the worker is either
// shutting down, or has finished shutting down. In both
// cases, there is nothing to clean up, so we don't care
// whether this message arrives or not.
}
}
connection.cancelForwarding(forwardingPrefix);
},
onPacket: packet => {
// Ensure that any packets received from the server on the worker
// thread are forwarded to the client on the main thread, as if
// they had been sent by the server on the main thread.
connection.send(packet);
},
};
// Ensure that any packets received from the client on the main thread
// to actors on the worker thread are forwarded to the server on the
// worker thread.
connection.setForwarding(forwardingPrefix, transport);
resolve({
workerTargetForm: message.workerTargetForm,
transport,
});
},
};
dbg.addListener(listener);
});
}
exports.connectToWorker = connectToWorker;