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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
/* eslint-env mozilla/process-script */
"use strict";
/**
* Main entry point for DevTools in content processes.
*
* This module is loaded early when a content process is started.
* Note that (at least) JS XPCOM registered at app-startup, will be running before.
* It is used by the multiprocess browser toolbox in order to debug privileged resources.
* When debugging a Web page loaded in a Tab, DevToolsFrame JS Window Actor is used instead
* (DevToolsFrameParent.jsm and DevToolsFrameChild.jsm).
*
* This module won't do anything unless DevTools codebase starts adding some data
* in `Services.cpmm.sharedData` object or send a message manager message via `Services.cpmm`.
* Also, this module is only loaded, on-demand from process-helper if devtools are watching for process targets.
*/
const SHARED_DATA_KEY_NAME = "DevTools:watchedPerWatcher";
class ContentProcessStartup {
constructor() {
// The map is indexed by the Watcher Actor ID.
// The values are objects containing the following properties:
// - connection: the DevToolsServerConnection itself
// - actor: the ContentProcessTargetActor instance
this._connections = new Map();
this.observe = this.observe.bind(this);
this.receiveMessage = this.receiveMessage.bind(this);
this.addListeners();
this.maybeCreateExistingTargetActors();
}
observe(subject, topic) {
switch (topic) {
case "xpcom-shutdown": {
this.destroy();
break;
}
}
}
destroy(options) {
this.removeListeners();
for (const [, connectionInfo] of this._connections) {
connectionInfo.connection.close(options);
}
this._connections.clear();
}
addListeners() {
Services.obs.addObserver(this.observe, "xpcom-shutdown");
Services.cpmm.addMessageListener(
"debug:instantiate-already-available",
this.receiveMessage
);
Services.cpmm.addMessageListener(
"debug:destroy-target",
this.receiveMessage
);
Services.cpmm.addMessageListener(
"debug:add-or-set-session-data-entry",
this.receiveMessage
);
Services.cpmm.addMessageListener(
"debug:remove-session-data-entry",
this.receiveMessage
);
Services.cpmm.addMessageListener(
"debug:destroy-process-script",
this.receiveMessage
);
}
removeListeners() {
Services.obs.removeObserver(this.observe, "xpcom-shutdown");
Services.cpmm.removeMessageListener(
"debug:instantiate-already-available",
this.receiveMessage
);
Services.cpmm.removeMessageListener(
"debug:destroy-target",
this.receiveMessage
);
Services.cpmm.removeMessageListener(
"debug:add-or-set-session-data-entry",
this.receiveMessage
);
Services.cpmm.removeMessageListener(
"debug:remove-session-data-entry",
this.receiveMessage
);
Services.cpmm.removeMessageListener(
"debug:destroy-process-script",
this.receiveMessage
);
}
receiveMessage(msg) {
switch (msg.name) {
case "debug:instantiate-already-available":
this.createTargetActor(
msg.data.watcherActorID,
msg.data.connectionPrefix,
msg.data.sessionData,
true
);
break;
case "debug:destroy-target":
this.destroyTarget(msg.data.watcherActorID);
break;
case "debug:add-or-set-session-data-entry":
this.addOrSetSessionDataEntry(
msg.data.watcherActorID,
msg.data.type,
msg.data.entries,
msg.data.updateType
);
break;
case "debug:remove-session-data-entry":
this.removeSessionDataEntry(
msg.data.watcherActorID,
msg.data.type,
msg.data.entries
);
break;
case "debug:destroy-process-script":
this.destroy(msg.data.options);
break;
default:
throw new Error(`Unsupported message name ${msg.name}`);
}
}
/**
* Called when the content process just started.
* This will start creating ContentProcessTarget actors, but only if DevTools code (WatcherActor / ParentProcessWatcherRegistry.sys.mjs)
* put some data in `sharedData` telling us to do so.
*/
maybeCreateExistingTargetActors() {
const { sharedData } = Services.cpmm;
// Accessing `sharedData` right off the app-startup returns null.
// Spinning the event loop with dispatchToMainThread seems enough,
// but it means that we let some more Javascript code run before
// instantiating the target actor.
// So we may miss a few resources and will register the breakpoints late.
if (!sharedData) {
Services.tm.dispatchToMainThread(
this.maybeCreateExistingTargetActors.bind(this)
);
return;
}
const sessionDataByWatcherActor = sharedData.get(SHARED_DATA_KEY_NAME);
if (!sessionDataByWatcherActor) {
return;
}
// Create one Target actor for each prefix/client which listen to process
for (const [watcherActorID, sessionData] of sessionDataByWatcherActor) {
const { connectionPrefix, targets } = sessionData;
// This is where we only do something significant only if DevTools are opened
// and requesting to create target actor for content processes
if (targets?.includes("process")) {
this.createTargetActor(watcherActorID, connectionPrefix, sessionData);
}
}
}
/**
* Instantiate a new ContentProcessTarget for the given connection.
* This is where we start doing some significant computation that only occurs when DevTools are opened.
*
* @param String watcherActorID
* The ID of the WatcherActor who requested to observe and create these target actors.
* @param String parentConnectionPrefix
* The prefix of the DevToolsServerConnection of the Watcher Actor.
* This is used to compute a unique ID for the target actor.
* @param Object sessionData
* All data managed by the Watcher Actor and ParentProcessWatcherRegistry.jsm, containing
* target types, resources types to be listened as well as breakpoints and any
* other data meant to be shared across processes and threads.
* @param Object options Dictionary with optional values:
* @param Boolean options.ignoreAlreadyCreated
* If true, do not throw if the target actor has already been created.
*/
createTargetActor(
watcherActorID,
parentConnectionPrefix,
sessionData,
ignoreAlreadyCreated = false
) {
if (this._connections.get(watcherActorID)) {
if (ignoreAlreadyCreated) {
return;
}
throw new Error(
"ContentProcessStartup createTargetActor was called more than once" +
` for the Watcher Actor (ID: "${watcherActorID}")`
);
}
// Compute a unique prefix, just for this content process,
// which will be used to create a ChildDebuggerTransport pair between content and parent processes.
// This is slightly hacky as we typicaly compute Prefix and Actor ID via `DevToolsServerConnection.allocID()`,
// but here, we can't have access to any DevTools connection as we are really early in the content process startup
const prefix =
parentConnectionPrefix + "contentProcess" + Services.appinfo.processID;
//TODO: probably merge content-process.jsm with this module
const { initContentProcessTarget } = ChromeUtils.importESModule(
"resource://devtools/server/startup/content-process.sys.mjs"
);
const { actor, connection } = initContentProcessTarget({
target: Services.cpmm,
data: {
watcherActorID,
parentConnectionPrefix,
prefix,
sessionContext: sessionData.sessionContext,
},
});
this._connections.set(watcherActorID, {
actor,
connection,
});
// Pass initialization data to the target actor
for (const type in sessionData) {
actor.addOrSetSessionDataEntry(type, sessionData[type], false, "set");
}
}
destroyTarget(watcherActorID) {
const connectionInfo = this._connections.get(watcherActorID);
// This connection has already been cleaned?
if (!connectionInfo) {
throw new Error(
`Trying to destroy a content process target actor that doesn't exists, or has already been destroyed. Watcher Actor ID:${watcherActorID}`
);
}
connectionInfo.connection.close();
this._connections.delete(watcherActorID);
}
async addOrSetSessionDataEntry(watcherActorID, type, entries, updateType) {
const connectionInfo = this._connections.get(watcherActorID);
if (!connectionInfo) {
throw new Error(
`No content process target actor for this Watcher Actor ID:"${watcherActorID}"`
);
}
const { actor } = connectionInfo;
await actor.addOrSetSessionDataEntry(type, entries, false, updateType);
Services.cpmm.sendAsyncMessage("debug:add-or-set-session-data-entry-done", {
watcherActorID,
});
}
removeSessionDataEntry(watcherActorID, type, entries) {
const connectionInfo = this._connections.get(watcherActorID);
if (!connectionInfo) {
return;
}
const { actor } = connectionInfo;
actor.removeSessionDataEntry(type, entries);
}
}
// Only start this component for content processes.
// i.e. explicitely avoid running it for the parent process
if (Services.appinfo.processType == Services.appinfo.PROCESS_TYPE_CONTENT) {
new ContentProcessStartup();
}