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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
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
const {
TYPES: { NETWORK_EVENT_STACKTRACE },
} = require("resource://devtools/server/actors/resources/index.js");
loader.lazyRequireGetter(
this,
"ChannelEventSinkFactory",
"resource://devtools/server/actors/network-monitor/channel-event-sink.js",
true
);
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
NetworkUtils:
"resource://devtools/shared/network-observer/NetworkUtils.sys.mjs",
});
class NetworkEventStackTracesWatcher {
/**
* Start watching for all network event's stack traces related to a given Target actor.
*
* @param TargetActor targetActor
* The target actor from which we should observe the strack traces
* @param Object options
* Dictionary object with following attributes:
* - onAvailable: mandatory
* This will be called for each resource.
*/
async watch(targetActor, { onAvailable }) {
this.stacktraces = new Map();
this.onStackTraceAvailable = onAvailable;
this.targetActor = targetActor;
Services.obs.addObserver(this, "http-on-opening-request");
Services.obs.addObserver(this, "document-on-opening-request");
Services.obs.addObserver(this, "network-monitor-alternate-stack");
ChannelEventSinkFactory.getService().registerCollector(this);
}
/**
* Allows clearing of network stacktrace resources
*/
clear() {
this.stacktraces.clear();
}
/**
* Stop watching for network event's strack traces related to a given Target Actor.
*
* @param TargetActor targetActor
* The target actor from which we should stop observing the strack traces
*/
destroy(targetActor) {
this.clear();
Services.obs.removeObserver(this, "http-on-opening-request");
Services.obs.removeObserver(this, "document-on-opening-request");
Services.obs.removeObserver(this, "network-monitor-alternate-stack");
ChannelEventSinkFactory.getService().unregisterCollector(this);
}
onChannelRedirect(oldChannel, newChannel, flags) {
// We can be called with any nsIChannel, but are interested only in HTTP channels
try {
oldChannel.QueryInterface(Ci.nsIHttpChannel);
newChannel.QueryInterface(Ci.nsIHttpChannel);
} catch (ex) {
return;
}
const oldId = oldChannel.channelId;
const stacktrace = this.stacktraces.get(oldId);
if (stacktrace) {
this._setStackTrace(newChannel.channelId, stacktrace);
}
}
observe(subject, topic, data) {
let channel, id;
try {
// We need to QI nsIHttpChannel in order to load the interface's
// methods / attributes for later code that could assume we are dealing
// with a nsIHttpChannel.
channel = subject.QueryInterface(Ci.nsIHttpChannel);
id = channel.channelId;
} catch (e1) {
try {
channel = subject.QueryInterface(Ci.nsIIdentChannel);
id = channel.channelId;
} catch (e2) {
// WebSocketChannels do not have IDs, so use the serial. When a WebSocket is
// opened in a content process, a channel is created locally but the HTTP
// channel for the connection lives entirely in the parent process. When
// the server code running in the parent sees that HTTP channel, it will
// look for the creation stack using the websocket's serial.
try {
channel = subject.QueryInterface(Ci.nsIWebSocketChannel);
id = channel.serial;
} catch (e3) {
// Try if the channel is a nsIWorkerChannelInfo which is the substitute
// of the channel in the parent process.
try {
channel = subject.QueryInterface(Ci.nsIWorkerChannelInfo);
id = channel.channelId;
} catch (e4) {
// Channels which don't implement the above interfaces can appear here,
// such as nsIFileChannel. Ignore these channels.
return;
}
}
}
}
if (
!lazy.NetworkUtils.matchRequest(channel, {
targetActor: this.targetActor,
})
) {
return;
}
if (this.stacktraces.has(id)) {
// We can get up to two stack traces for the same channel: one each from
// the two observer topics we are listening to. Use the first stack trace
// which is specified, and ignore any later one.
return;
}
const stacktrace = [];
switch (topic) {
case "http-on-opening-request":
case "document-on-opening-request": {
// The channel is being opened on the main thread, associate the current
// stack with it.
//
// Convert the nsIStackFrame XPCOM objects to a nice JSON that can be
// passed around through message managers etc.
let frame = Components.stack;
if (frame?.caller) {
frame = frame.caller;
while (frame) {
stacktrace.push({
filename: frame.filename,
lineNumber: frame.lineNumber,
columnNumber: frame.columnNumber,
functionName: frame.name,
asyncCause: frame.asyncCause,
});
frame = frame.caller || frame.asyncCaller;
}
}
break;
}
case "network-monitor-alternate-stack": {
// An alternate stack trace is being specified for this channel.
// The topic data is the JSON for the saved frame stack we should use,
// so convert this into the expected format.
//
// This topic is used in the following cases:
//
// - The HTTP channel is opened asynchronously or on a different thread
// from the code which triggered its creation, in which case the stack
// from Components.stack will be empty. The alternate stack will be
// for the point we want to associate with the channel.
//
// - The channel is not a nsIHttpChannel, and we will receive no
// opening request notification for it.
let frame = JSON.parse(data);
while (frame) {
stacktrace.push({
filename: frame.source,
lineNumber: frame.line,
columnNumber: frame.column,
functionName: frame.functionDisplayName,
asyncCause: frame.asyncCause,
});
frame = frame.parent || frame.asyncParent;
}
break;
}
default:
throw new Error("Unexpected observe() topic");
}
this._setStackTrace(id, stacktrace);
}
_setStackTrace(resourceId, stacktrace) {
this.stacktraces.set(resourceId, stacktrace);
this.onStackTraceAvailable([
{
resourceType: NETWORK_EVENT_STACKTRACE,
resourceId,
stacktraceAvailable: stacktrace && !!stacktrace.length,
lastFrame: stacktrace && stacktrace.length ? stacktrace[0] : undefined,
},
]);
}
getStackTrace(id) {
let stacktrace = [];
if (this.stacktraces.has(id)) {
stacktrace = this.stacktraces.get(id);
}
return stacktrace;
}
}
module.exports = NetworkEventStackTracesWatcher;
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