forked from mirrors/gecko-dev
f74b84ea35
Asynchronously opening a connection through the Sqlite module may intersect a shutdown phase so that the request for the connection happens when the phase is still open, but the callback is invoked after the phase has been closed. In this case adding a shutdown blocker to close the connection will fail and async shutdown is likely to crash after waiting for the Sqlite module. In these edge cases it's safer to just close the connection and reject to the consumer. Differential Revision: https://phabricator.services.mozilla.com/D164597
1131 lines
36 KiB
JavaScript
1131 lines
36 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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/**
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* Managing safe shutdown of asynchronous services.
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*
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* Firefox shutdown is composed of phases that take place
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* sequentially. Typically, each shutdown phase removes some
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* capabilities from the application. For instance, at the end of
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* phase profileBeforeChange, no service is permitted to write to the
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* profile directory (with the exception of Telemetry). Consequently,
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* if any service has requested I/O to the profile directory before or
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* during phase profileBeforeChange, the system must be informed that
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* these requests need to be completed before the end of phase
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* profileBeforeChange. Failing to inform the system of this
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* requirement can (and has been known to) cause data loss.
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*
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* Example: At some point during shutdown, the Add-On Manager needs to
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* ensure that all add-ons have safely written their data to disk,
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* before writing its own data. Since the data is saved to the
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* profile, this must be completed during phase profileBeforeChange.
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*
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* AsyncShutdown.profileBeforeChange.addBlocker(
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* "Add-on manager: shutting down",
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* function condition() {
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* // Do things.
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* // Perform I/O that must take place during phase profile-before-change
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* return promise;
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* }
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* });
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*
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* In this example, function |condition| will be called at some point
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* during phase profileBeforeChange and phase profileBeforeChange
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* itself is guaranteed to not terminate until |promise| is either
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* resolved or rejected.
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*/
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import { XPCOMUtils } from "resource://gre/modules/XPCOMUtils.sys.mjs";
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const lazy = {};
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ChromeUtils.defineESModuleGetters(lazy, {
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PromiseUtils: "resource://gre/modules/PromiseUtils.sys.mjs",
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});
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XPCOMUtils.defineLazyServiceGetter(
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lazy,
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"gDebug",
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"@mozilla.org/xpcom/debug;1",
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"nsIDebug2"
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);
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// `true` if this is a content process, `false` otherwise.
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// It would be nicer to go through `Services.appinfo`, but some tests need to be
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// able to replace that field with a custom implementation before it is first
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// called.
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const isContent =
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// eslint-disable-next-line mozilla/use-services
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Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime).processType ==
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Ci.nsIXULRuntime.PROCESS_TYPE_CONTENT;
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// Display timeout warnings after 10 seconds
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const DELAY_WARNING_MS = 10 * 1000;
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// Crash the process if shutdown is really too long
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// (allowing for sleep).
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const PREF_DELAY_CRASH_MS = "toolkit.asyncshutdown.crash_timeout";
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var DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS, 60 * 1000); // One minute
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Services.prefs.addObserver(PREF_DELAY_CRASH_MS, function() {
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DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS);
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});
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/**
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* Any addBlocker calls that failed. We add this into barrier wait
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* crash annotations to help with debugging. When we fail to add
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* shutdown blockers that can break shutdown. We track these globally
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* rather than per barrier because one failure mode is when the
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* barrier has already finished by the time addBlocker is invoked -
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* but the failure to add the blocker may result in later barriers
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* waiting indefinitely, so the debug information is still useful
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* for those later barriers. See bug 1801674 for more context.
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*/
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let gBrokenAddBlockers = [];
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/**
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* A set of Promise that supports waiting.
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*
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* Promise items may be added or removed during the wait. The wait will
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* resolve once all Promise items have been resolved or removed.
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*/
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function PromiseSet() {
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/**
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* key: the Promise passed pass the client of the `PromiseSet`.
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* value: an indirection on top of `key`, as an object with
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* the following fields:
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* - indirection: a Promise resolved if `key` is resolved or
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* if `resolve` is called
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* - resolve: a function used to resolve the indirection.
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*/
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this._indirections = new Map();
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// Once all the tracked promises have been resolved we are done. Once Wait()
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// resolves, it should not be possible anymore to add further promises.
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// This covers for a possibly rare case, where something may try to add a
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// blocker after wait() is done, that would never be awaited for.
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this._done = false;
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}
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PromiseSet.prototype = {
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/**
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* Wait until all Promise have been resolved or removed.
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*
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* Note that calling `wait()` causes Promise to be removed from the
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* Set once they are resolved.
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* @param {function} onDoneCb invoked synchronously once all the entries
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* have been handled and no new entries will be accepted.
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* @return {Promise} Resolved once all Promise have been resolved or removed,
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* or rejected after at least one Promise has rejected.
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*/
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wait(onDoneCb) {
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// Pick an arbitrary element in the map, if any exists.
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let entry = this._indirections.entries().next();
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if (entry.done) {
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// No indirections left, we are done.
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this._done = true;
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onDoneCb();
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return Promise.resolve();
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}
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let [, indirection] = entry.value;
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let promise = indirection.promise;
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promise = promise.then(() =>
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// At this stage, the entry has been cleaned up.
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this.wait(onDoneCb)
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);
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return promise;
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},
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/**
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* Add a new Promise to the set.
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*
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* Calls to wait (including ongoing calls) will only return once
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* `key` has either resolved or been removed.
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*/
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add(key) {
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if (this._done) {
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throw new Error("Wait is complete, cannot add further promises.");
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}
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this._ensurePromise(key);
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let indirection = lazy.PromiseUtils.defer();
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key
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.then(
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x => {
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// Clean up immediately.
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// This needs to be done before the call to `resolve`, otherwise
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// `wait()` may loop forever.
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this._indirections.delete(key);
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indirection.resolve(x);
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},
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err => {
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this._indirections.delete(key);
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indirection.reject(err);
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}
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)
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.finally(() => {
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this._indirections.delete(key);
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// Normally the promise is resolved or rejected, but if its global
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// goes away, only finally may be invoked. In all the other cases this
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// is a no-op since the promise has been fulfilled already.
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indirection.reject(
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new Error("Promise not fulfilled, did it lost its global?")
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);
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});
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this._indirections.set(key, indirection);
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},
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/**
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* Remove a Promise from the set.
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*
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* Calls to wait (including ongoing calls) will ignore this promise,
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* unless it is added again.
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*/
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delete(key) {
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this._ensurePromise(key);
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let value = this._indirections.get(key);
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if (!value) {
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return false;
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}
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this._indirections.delete(key);
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value.resolve();
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return true;
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},
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_ensurePromise(key) {
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if (!key || typeof key != "object") {
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throw new Error("Expected an object");
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}
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if (!("then" in key) || typeof key.then != "function") {
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throw new Error("Expected a Promise");
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}
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},
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};
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/**
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* Display a warning.
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*
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* As this code is generally used during shutdown, there are chances
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* that the UX will not be available to display warnings on the
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* console. We therefore use dump() rather than Cu.reportError().
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*/
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function log(msg, prefix = "", error = null) {
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try {
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dump(prefix + msg + "\n");
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if (error) {
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dump(prefix + error + "\n");
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if (typeof error == "object" && "stack" in error) {
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dump(prefix + error.stack + "\n");
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}
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}
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} catch (ex) {
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dump("INTERNAL ERROR in AsyncShutdown: cannot log message.\n");
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}
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}
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const PREF_DEBUG_LOG = "toolkit.asyncshutdown.log";
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var DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG, false);
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Services.prefs.addObserver(PREF_DEBUG_LOG, function() {
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DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG);
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});
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function debug(msg, error = null) {
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if (DEBUG_LOG) {
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log(msg, "DEBUG: ", error);
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}
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}
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function warn(msg, error = null) {
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log(msg, "WARNING: ", error);
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}
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function fatalerr(msg, error = null) {
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log(msg, "FATAL ERROR: ", error);
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}
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// Utility function designed to get the current state of execution
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// of a blocker.
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// We are a little paranoid here to ensure that in case of evaluation
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// error we do not block the AsyncShutdown.
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function safeGetState(fetchState) {
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if (!fetchState) {
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return "(none)";
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}
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let data, string;
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try {
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// Evaluate fetchState(), normalize the result into something that we can
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// safely stringify or upload.
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let state = fetchState();
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if (!state) {
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return "(none)";
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}
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string = JSON.stringify(state);
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data = JSON.parse(string);
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// Simplify the rest of the code by ensuring that we can simply
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// concatenate the result to a message.
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if (data && typeof data == "object") {
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data.toString = function() {
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return string;
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};
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}
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return data;
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} catch (ex) {
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// Make sure that this causes test failures
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Promise.reject(ex);
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if (string) {
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return string;
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}
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try {
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return "Error getting state: " + ex + " at " + ex.stack;
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} catch (ex2) {
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return "Error getting state but could not display error";
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}
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}
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}
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/**
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* Countdown for a given duration, skipping beats if the computer is too busy,
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* sleeping or otherwise unavailable.
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*
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* @param {number} delay An approximate delay to wait in milliseconds (rounded
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* up to the closest second).
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*
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* @return Deferred
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*/
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function looseTimer(delay) {
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let DELAY_BEAT = 1000;
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let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
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let beats = Math.ceil(delay / DELAY_BEAT);
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let deferred = lazy.PromiseUtils.defer();
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timer.initWithCallback(
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function() {
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if (beats <= 0) {
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deferred.resolve();
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}
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--beats;
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},
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DELAY_BEAT,
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Ci.nsITimer.TYPE_REPEATING_PRECISE_CAN_SKIP
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);
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// Ensure that the timer is both canceled once we are done with it
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// and not garbage-collected until then.
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deferred.promise.then(
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() => timer.cancel(),
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() => timer.cancel()
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);
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return deferred;
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}
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/**
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* Given an nsIStackFrame object, find the caller filename, line number,
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* and stack if necessary, and return them as an object.
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*
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* @param {nsIStackFrame} topFrame Top frame of the call stack.
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* @param {string} filename Pre-supplied filename or null if unknown.
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* @param {number} lineNumber Pre-supplied line number or null if unknown.
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* @param {string} stack Pre-supplied stack or null if unknown.
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*
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* @return object
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*/
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function getOrigin(topFrame, filename = null, lineNumber = null, stack = null) {
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try {
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// Determine the filename and line number of the caller.
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let frame = topFrame;
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for (; frame && frame.filename == topFrame.filename; frame = frame.caller) {
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// Climb up the stack
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}
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if (filename == null) {
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filename = frame ? frame.filename : "?";
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}
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if (lineNumber == null) {
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lineNumber = frame ? frame.lineNumber : 0;
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}
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if (stack == null) {
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// Now build the rest of the stack as a string, using Task.jsm's rewriting
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// to ensure that we do not lose information at each call to `Task.spawn`.
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stack = [];
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while (frame != null) {
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stack.push(frame.filename + ":" + frame.name + ":" + frame.lineNumber);
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frame = frame.caller;
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}
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}
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return {
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filename,
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lineNumber,
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stack,
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};
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} catch (ex) {
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return {
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filename: "<internal error: could not get origin>",
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lineNumber: -1,
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stack: "<internal error: could not get origin>",
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};
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}
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}
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/**
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* {string} topic -> phase
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*/
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var gPhases = new Map();
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export var AsyncShutdown = {
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/**
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* Access function getPhase. For testing purposes only.
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*/
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get _getPhase() {
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let accepted = Services.prefs.getBoolPref(
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"toolkit.asyncshutdown.testing",
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false
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);
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if (accepted) {
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return getPhase;
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}
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return undefined;
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},
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/**
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* This constant is used as the amount of milliseconds to allow shutdown to be
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* blocked until we crash the process forcibly and is read from the
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* 'toolkit.asyncshutdown.crash_timeout' pref.
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*/
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get DELAY_CRASH_MS() {
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return DELAY_CRASH_MS;
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},
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};
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/**
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* Register a new phase.
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*
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* @param {string} topic The notification topic for this Phase.
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* @see {https://developer.mozilla.org/en-US/docs/Observer_Notifications}
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*/
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function getPhase(topic) {
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let phase = gPhases.get(topic);
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if (phase) {
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return phase;
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}
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let spinner = new Spinner(topic);
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phase = Object.freeze({
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/**
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* Register a blocker for the completion of a phase.
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*
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* @param {string} name The human-readable name of the blocker. Used
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* for debugging/error reporting. Please make sure that the name
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* respects the following model: "Some Service: some action in progress" -
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* for instance "OS.File: flushing all pending I/O";
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* @param {function|promise|*} condition A condition blocking the
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* completion of the phase. Generally, this is a function
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* returning a promise. This function is evaluated during the
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* phase and the phase is guaranteed to not terminate until the
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* resulting promise is either resolved or rejected. If
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* |condition| is not a function but another value |v|, it behaves
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* as if it were a function returning |v|.
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* @param {object*} details Optionally, an object with details
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* that may be useful for error reporting, as a subset of of the following
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* fields:
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* - fetchState (strongly recommended) A function returning
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* information about the current state of the blocker as an
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* object. Used for providing more details when logging errors or
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* crashing.
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* - stack. A string containing stack information. This module can
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* generally infer stack information if it is not provided.
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* - lineNumber A number containing the line number for the caller.
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* This module can generally infer this information if it is not
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* provided.
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* - filename A string containing the filename for the caller. This
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* module can generally infer the information if it is not provided.
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*
|
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* Examples:
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* AsyncShutdown.profileBeforeChange.addBlocker("Module: just a promise",
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* promise); // profileBeforeChange will not complete until
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* // promise is resolved or rejected
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*
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* AsyncShutdown.profileBeforeChange.addBlocker("Module: a callback",
|
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* function callback() {
|
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* // ...
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* // Execute this code during profileBeforeChange
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* return promise;
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* // profileBeforeChange will not complete until promise
|
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* // is resolved or rejected
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* });
|
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*
|
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* AsyncShutdown.profileBeforeChange.addBlocker("Module: trivial callback",
|
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* function callback() {
|
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* // ...
|
|
* // Execute this code during profileBeforeChange
|
|
* // No specific guarantee about completion of profileBeforeChange
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* });
|
|
*/
|
|
addBlocker(name, condition, details = null) {
|
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spinner.addBlocker(name, condition, details);
|
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},
|
|
/**
|
|
* Remove the blocker for a condition.
|
|
*
|
|
* If several blockers have been registered for the same
|
|
* condition, remove all these blockers. If no blocker has been
|
|
* registered for this condition, this is a noop.
|
|
*
|
|
* @return {boolean} true if a blocker has been removed, false
|
|
* otherwise. Note that a result of false may mean either that
|
|
* the blocker has never been installed or that the phase has
|
|
* completed and the blocker has already been resolved.
|
|
*/
|
|
removeBlocker(condition) {
|
|
return spinner.removeBlocker(condition);
|
|
},
|
|
|
|
get name() {
|
|
return spinner.name;
|
|
},
|
|
|
|
get isClosed() {
|
|
return spinner.isClosed;
|
|
},
|
|
|
|
/**
|
|
* Trigger the phase without having to broadcast a
|
|
* notification. For testing purposes only.
|
|
*/
|
|
get _trigger() {
|
|
let accepted = Services.prefs.getBoolPref(
|
|
"toolkit.asyncshutdown.testing",
|
|
false
|
|
);
|
|
if (accepted) {
|
|
return () => spinner.observe();
|
|
}
|
|
return undefined;
|
|
},
|
|
});
|
|
gPhases.set(topic, phase);
|
|
return phase;
|
|
}
|
|
|
|
/**
|
|
* Utility class used to spin the event loop until all blockers for a
|
|
* Phase are satisfied.
|
|
*
|
|
* @param {string} topic The xpcom notification for that phase.
|
|
*/
|
|
function Spinner(topic) {
|
|
this._barrier = new Barrier(topic);
|
|
this._topic = topic;
|
|
Services.obs.addObserver(this, topic);
|
|
}
|
|
|
|
Spinner.prototype = {
|
|
/**
|
|
* Register a new condition for this phase.
|
|
*
|
|
* See the documentation of `addBlocker` in property `client`
|
|
* of instances of `Barrier`.
|
|
*/
|
|
addBlocker(name, condition, details) {
|
|
this._barrier.client.addBlocker(name, condition, details);
|
|
},
|
|
/**
|
|
* Remove the blocker for a condition.
|
|
*
|
|
* See the documentation of `removeBlocker` in rpoperty `client`
|
|
* of instances of `Barrier`
|
|
*
|
|
* @return {boolean} true if a blocker has been removed, false
|
|
* otherwise. Note that a result of false may mean either that
|
|
* the blocker has never been installed or that the phase has
|
|
* completed and the blocker has already been resolved.
|
|
*/
|
|
removeBlocker(condition) {
|
|
return this._barrier.client.removeBlocker(condition);
|
|
},
|
|
|
|
get name() {
|
|
return this._barrier.client.name;
|
|
},
|
|
|
|
get isClosed() {
|
|
return this._barrier.client.isClosed;
|
|
},
|
|
|
|
// nsIObserver.observe
|
|
observe() {
|
|
let topic = this._topic;
|
|
debug(`Starting phase ${topic}`);
|
|
Services.obs.removeObserver(this, topic);
|
|
|
|
let satisfied = false; // |true| once we have satisfied all conditions
|
|
let promise;
|
|
try {
|
|
promise = this._barrier
|
|
.wait({
|
|
warnAfterMS: DELAY_WARNING_MS,
|
|
crashAfterMS: DELAY_CRASH_MS,
|
|
})
|
|
.catch
|
|
// Additional precaution to be entirely sure that we cannot reject.
|
|
();
|
|
} catch (ex) {
|
|
debug("Error waiting for notification");
|
|
throw ex;
|
|
}
|
|
|
|
// Now, spin the event loop
|
|
debug("Spinning the event loop");
|
|
promise.then(() => (satisfied = true)); // This promise cannot reject
|
|
let thread = Services.tm.mainThread;
|
|
while (!satisfied) {
|
|
try {
|
|
thread.processNextEvent(true);
|
|
} catch (ex) {
|
|
// An uncaught error should not stop us, but it should still
|
|
// be reported and cause tests to fail.
|
|
Promise.reject(ex);
|
|
}
|
|
}
|
|
debug(`Finished phase ${topic}`);
|
|
},
|
|
};
|
|
|
|
/**
|
|
* A mechanism used to register blockers that prevent some action from
|
|
* happening.
|
|
*
|
|
* An instance of |Barrier| provides a capability |client| that
|
|
* clients can use to register blockers. The barrier is resolved once
|
|
* all registered blockers have been resolved. The owner of the
|
|
* |Barrier| may wait for the resolution of the barrier and obtain
|
|
* information on which blockers have not been resolved yet.
|
|
*
|
|
* @param {string} name The name of the blocker. Used mainly for error-
|
|
* reporting.
|
|
*/
|
|
function Barrier(name) {
|
|
if (!name) {
|
|
throw new TypeError("Instances of Barrier need a (non-empty) name");
|
|
}
|
|
|
|
/**
|
|
* The set of all Promise for which we need to wait before the barrier
|
|
* is lifted. Note that this set may be changed while we are waiting.
|
|
*
|
|
* Set to `null` once the wait is complete.
|
|
*/
|
|
this._waitForMe = new PromiseSet();
|
|
|
|
/**
|
|
* A map from conditions, as passed by users during the call to `addBlocker`,
|
|
* to `promise`, as present in `this._waitForMe`.
|
|
*
|
|
* Used to let users perform cleanup through `removeBlocker`.
|
|
* Set to `null` once the wait is complete.
|
|
*
|
|
* Key: condition (any, as passed by user)
|
|
* Value: promise used as a key in `this._waitForMe`. Note that there is
|
|
* no guarantee that the key is still present in `this._waitForMe`.
|
|
*/
|
|
this._conditionToPromise = new Map();
|
|
|
|
/**
|
|
* A map from Promise, as present in `this._waitForMe` or
|
|
* `this._conditionToPromise`, to information on blockers.
|
|
*
|
|
* Key: Promise (as present in this._waitForMe or this._conditionToPromise).
|
|
* Value: {
|
|
* trigger: function,
|
|
* promise,
|
|
* name,
|
|
* fetchState: function,
|
|
* stack,
|
|
* filename,
|
|
* lineNumber
|
|
* };
|
|
*/
|
|
this._promiseToBlocker = new Map();
|
|
|
|
/**
|
|
* The name of the barrier.
|
|
*/
|
|
if (typeof name != "string") {
|
|
throw new TypeError("The name of the barrier must be a string");
|
|
}
|
|
this._name = name;
|
|
|
|
/**
|
|
* A cache for the promise returned by wait().
|
|
*/
|
|
this._promise = null;
|
|
|
|
/**
|
|
* `true` once we have started waiting.
|
|
*/
|
|
this._isStarted = false;
|
|
|
|
/**
|
|
* `true` once we're done and won't accept any new blockers.
|
|
*/
|
|
this._isClosed = false;
|
|
|
|
/**
|
|
* The capability of adding blockers. This object may safely be returned
|
|
* or passed to clients.
|
|
*/
|
|
this.client = {
|
|
/**
|
|
* The name of the barrier owning this client.
|
|
*/
|
|
get name() {
|
|
return name;
|
|
},
|
|
|
|
/**
|
|
* Register a blocker for the completion of this barrier.
|
|
*
|
|
* @param {string} name The human-readable name of the blocker. Used
|
|
* for debugging/error reporting. Please make sure that the name
|
|
* respects the following model: "Some Service: some action in progress" -
|
|
* for instance "OS.File: flushing all pending I/O";
|
|
* @param {function|promise|*} condition A condition blocking the
|
|
* completion of the phase. Generally, this is a function
|
|
* returning a promise. This function is evaluated during the
|
|
* phase and the phase is guaranteed to not terminate until the
|
|
* resulting promise is either resolved or rejected. If
|
|
* |condition| is not a function but another value |v|, it behaves
|
|
* as if it were a function returning |v|.
|
|
* @param {object*} details Optionally, an object with details
|
|
* that may be useful for error reporting, as a subset of of the following
|
|
* fields:
|
|
* - fetchState (strongly recommended) A function returning
|
|
* information about the current state of the blocker as an
|
|
* object. Used for providing more details when logging errors or
|
|
* crashing.
|
|
* - stack. A string containing stack information. This module can
|
|
* generally infer stack information if it is not provided.
|
|
* - lineNumber A number containing the line number for the caller.
|
|
* This module can generally infer this information if it is not
|
|
* provided.
|
|
* - filename A string containing the filename for the caller. This
|
|
* module can generally infer the information if it is not provided.
|
|
*/
|
|
addBlocker: (name, condition, details) => {
|
|
if (typeof name != "string") {
|
|
gBrokenAddBlockers.push("No-name blocker");
|
|
throw new TypeError("Expected a human-readable name as first argument");
|
|
}
|
|
if (details && typeof details == "function") {
|
|
details = {
|
|
fetchState: details,
|
|
};
|
|
} else if (!details) {
|
|
details = {};
|
|
}
|
|
if (typeof details != "object") {
|
|
gBrokenAddBlockers.push(`${name} - invalid details`);
|
|
throw new TypeError(
|
|
"Expected an object as third argument to `addBlocker`, got " + details
|
|
);
|
|
}
|
|
if (!this._waitForMe) {
|
|
gBrokenAddBlockers.push(`${name} - ${this._name} finished`);
|
|
throw new Error(
|
|
`Phase "${this._name}" is finished, it is too late to register completion condition "${name}"`
|
|
);
|
|
}
|
|
debug(`Adding blocker ${name} for phase ${this._name}`);
|
|
|
|
try {
|
|
this.client._internalAddBlocker(name, condition, details);
|
|
} catch (ex) {
|
|
gBrokenAddBlockers.push(`${name} - ${ex.message}`);
|
|
throw ex;
|
|
}
|
|
},
|
|
|
|
_internalAddBlocker: (
|
|
name,
|
|
condition,
|
|
{ fetchState = null, filename = null, lineNumber = null, stack = null }
|
|
) => {
|
|
if (fetchState != null && typeof fetchState != "function") {
|
|
throw new TypeError("Expected a function for option `fetchState`");
|
|
}
|
|
|
|
// Split the condition between a trigger function and a promise.
|
|
|
|
// The function to call to notify the blocker that we have started waiting.
|
|
// This function returns a promise resolved/rejected once the
|
|
// condition is complete, and never throws.
|
|
let trigger;
|
|
|
|
// A promise resolved once the condition is complete.
|
|
let promise;
|
|
if (typeof condition == "function") {
|
|
promise = new Promise((resolve, reject) => {
|
|
trigger = () => {
|
|
try {
|
|
resolve(condition());
|
|
} catch (ex) {
|
|
reject(ex);
|
|
}
|
|
};
|
|
});
|
|
} else {
|
|
// If `condition` is not a function, `trigger` is not particularly
|
|
// interesting, and `condition` needs to be normalized to a promise.
|
|
trigger = () => {};
|
|
promise = Promise.resolve(condition);
|
|
}
|
|
|
|
// Make sure that `promise` never rejects.
|
|
promise = promise
|
|
.catch(error => {
|
|
let msg = `A blocker encountered an error while we were waiting.
|
|
Blocker: ${name}
|
|
Phase: ${this._name}
|
|
State: ${safeGetState(fetchState)}`;
|
|
warn(msg, error);
|
|
|
|
// The error should remain uncaught, to ensure that it
|
|
// still causes tests to fail.
|
|
Promise.reject(error);
|
|
})
|
|
.catch
|
|
// Added as a last line of defense, in case `warn`, `this._name` or
|
|
// `safeGetState` somehow throws an error.
|
|
();
|
|
|
|
let topFrame = null;
|
|
if (filename == null || lineNumber == null || stack == null) {
|
|
topFrame = Components.stack;
|
|
}
|
|
|
|
let blocker = {
|
|
trigger,
|
|
promise,
|
|
name,
|
|
fetchState,
|
|
getOrigin: () => getOrigin(topFrame, filename, lineNumber, stack),
|
|
};
|
|
|
|
this._waitForMe.add(promise);
|
|
this._promiseToBlocker.set(promise, blocker);
|
|
this._conditionToPromise.set(condition, promise);
|
|
|
|
// As conditions may hold lots of memory, we attempt to cleanup
|
|
// as soon as we are done (which might be in the next tick, if
|
|
// we have been passed a resolved promise).
|
|
promise = promise.then(() => {
|
|
debug(`Completed blocker ${name} for phase ${this._name}`);
|
|
this._removeBlocker(condition);
|
|
});
|
|
|
|
if (this._isStarted) {
|
|
// The wait has already started. The blocker should be
|
|
// notified asap. We do it out of band as clients probably
|
|
// expect `addBlocker` to return immediately.
|
|
Promise.resolve().then(trigger);
|
|
}
|
|
},
|
|
|
|
/**
|
|
* Remove the blocker for a condition.
|
|
*
|
|
* If several blockers have been registered for the same
|
|
* condition, remove all these blockers. If no blocker has been
|
|
* registered for this condition, this is a noop.
|
|
*
|
|
* @return {boolean} true if at least one blocker has been
|
|
* removed, false otherwise.
|
|
*/
|
|
removeBlocker: condition => {
|
|
return this._removeBlocker(condition);
|
|
},
|
|
};
|
|
|
|
/**
|
|
* Whether this client still accepts new blockers.
|
|
*/
|
|
Object.defineProperty(this.client, "isClosed", {
|
|
get: () => {
|
|
return this._isClosed;
|
|
},
|
|
});
|
|
}
|
|
Barrier.prototype = Object.freeze({
|
|
/**
|
|
* The current state of the barrier, as a JSON-serializable object
|
|
* designed for error-reporting.
|
|
*/
|
|
get state() {
|
|
if (!this._isStarted) {
|
|
return "Not started";
|
|
}
|
|
if (!this._waitForMe) {
|
|
return "Complete";
|
|
}
|
|
let frozen = [];
|
|
for (let blocker of this._promiseToBlocker.values()) {
|
|
let { name, fetchState } = blocker;
|
|
let { stack, filename, lineNumber } = blocker.getOrigin();
|
|
frozen.push({
|
|
name,
|
|
state: safeGetState(fetchState),
|
|
filename,
|
|
lineNumber,
|
|
stack,
|
|
});
|
|
}
|
|
return frozen;
|
|
},
|
|
|
|
/**
|
|
* Wait until all currently registered blockers are complete.
|
|
*
|
|
* Once this method has been called, any attempt to register a new blocker
|
|
* for this barrier will cause an error.
|
|
*
|
|
* Successive calls to this method always return the same value.
|
|
*
|
|
* @param {object=} options Optionally, an object that may contain
|
|
* the following fields:
|
|
* {number} warnAfterMS If provided and > 0, print a warning if the barrier
|
|
* has not been resolved after the given number of milliseconds.
|
|
* {number} crashAfterMS If provided and > 0, crash the process if the barrier
|
|
* has not been resolved after the give number of milliseconds (rounded up
|
|
* to the next second). To avoid crashing simply because the computer is busy
|
|
* or going to sleep, we actually wait for ceil(crashAfterMS/1000) successive
|
|
* periods of at least one second. Upon crashing, if a crash reporter is present,
|
|
* prepare a crash report with the state of this barrier.
|
|
*
|
|
*
|
|
* @return {Promise} A promise satisfied once all blockers are complete.
|
|
*/
|
|
wait(options = {}) {
|
|
// This method only implements caching on top of _wait()
|
|
if (this._promise) {
|
|
return this._promise;
|
|
}
|
|
return (this._promise = this._wait(options));
|
|
},
|
|
_wait(options) {
|
|
// Sanity checks
|
|
if (this._isStarted) {
|
|
throw new TypeError("Internal error: already started " + this._name);
|
|
}
|
|
if (
|
|
!this._waitForMe ||
|
|
!this._conditionToPromise ||
|
|
!this._promiseToBlocker
|
|
) {
|
|
throw new TypeError("Internal error: already finished " + this._name);
|
|
}
|
|
|
|
let topic = this._name;
|
|
|
|
// Notify blockers
|
|
for (let blocker of this._promiseToBlocker.values()) {
|
|
blocker.trigger(); // We have guarantees that this method will never throw
|
|
}
|
|
|
|
this._isStarted = true;
|
|
|
|
// Now, wait
|
|
let promise = this._waitForMe.wait(() => {
|
|
this._isClosed = true;
|
|
});
|
|
|
|
promise = promise.catch(function onError(error) {
|
|
// I don't think that this can happen.
|
|
// However, let's be overcautious with async/shutdown error reporting.
|
|
let msg =
|
|
"An uncaught error appeared while completing the phase." +
|
|
" Phase: " +
|
|
topic;
|
|
warn(msg, error);
|
|
});
|
|
|
|
promise = promise.then(() => {
|
|
// Cleanup memory
|
|
this._waitForMe = null;
|
|
this._promiseToBlocker = null;
|
|
this._conditionToPromise = null;
|
|
});
|
|
|
|
// Now handle warnings and crashes
|
|
let warnAfterMS = DELAY_WARNING_MS;
|
|
if (options && "warnAfterMS" in options) {
|
|
if (
|
|
typeof options.warnAfterMS == "number" ||
|
|
options.warnAfterMS == null
|
|
) {
|
|
// Change the delay or deactivate warnAfterMS
|
|
warnAfterMS = options.warnAfterMS;
|
|
} else {
|
|
throw new TypeError("Wrong option value for warnAfterMS");
|
|
}
|
|
}
|
|
|
|
if (warnAfterMS && warnAfterMS > 0) {
|
|
// If the promise takes too long to be resolved/rejected,
|
|
// we need to notify the user.
|
|
let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
|
|
timer.initWithCallback(
|
|
() => {
|
|
let msg =
|
|
"At least one completion condition is taking too long to complete." +
|
|
" Conditions: " +
|
|
JSON.stringify(this.state) +
|
|
" Barrier: " +
|
|
topic;
|
|
warn(msg);
|
|
},
|
|
warnAfterMS,
|
|
Ci.nsITimer.TYPE_ONE_SHOT
|
|
);
|
|
|
|
promise = promise.then(function onSuccess() {
|
|
timer.cancel();
|
|
// As a side-effect, this prevents |timer| from
|
|
// being garbage-collected too early.
|
|
});
|
|
}
|
|
|
|
let crashAfterMS = DELAY_CRASH_MS;
|
|
if (options && "crashAfterMS" in options) {
|
|
if (
|
|
typeof options.crashAfterMS == "number" ||
|
|
options.crashAfterMS == null
|
|
) {
|
|
// Change the delay or deactivate crashAfterMS
|
|
crashAfterMS = options.crashAfterMS;
|
|
} else {
|
|
throw new TypeError("Wrong option value for crashAfterMS");
|
|
}
|
|
}
|
|
|
|
if (crashAfterMS > 0) {
|
|
let timeToCrash = null;
|
|
|
|
// If after |crashAfterMS| milliseconds (adjusted to take into
|
|
// account sleep and otherwise busy computer) we have not finished
|
|
// this shutdown phase, we assume that the shutdown is somehow
|
|
// frozen, presumably deadlocked. At this stage, the only thing we
|
|
// can do to avoid leaving the user's computer in an unstable (and
|
|
// battery-sucking) situation is report the issue and crash.
|
|
timeToCrash = looseTimer(crashAfterMS);
|
|
timeToCrash.promise.then(
|
|
() => {
|
|
// Report the problem as best as we can, then crash.
|
|
let state = this.state;
|
|
|
|
// If you change the following message, please make sure
|
|
// that any information on the topic and state appears
|
|
// within the first 200 characters of the message. This
|
|
// helps automatically sort oranges.
|
|
let msg =
|
|
"AsyncShutdown timeout in " +
|
|
topic +
|
|
" Conditions: " +
|
|
JSON.stringify(state) +
|
|
" At least one completion condition failed to complete" +
|
|
" within a reasonable amount of time. Causing a crash to" +
|
|
" ensure that we do not leave the user with an unresponsive" +
|
|
" process draining resources.";
|
|
fatalerr(msg);
|
|
if (gBrokenAddBlockers.length) {
|
|
fatalerr(
|
|
"Broken addBlocker calls: " + JSON.stringify(gBrokenAddBlockers)
|
|
);
|
|
}
|
|
if (Services.appinfo.crashReporterEnabled) {
|
|
Services.appinfo.annotateCrashReport(
|
|
"AsyncShutdownTimeout",
|
|
JSON.stringify(this._gatherCrashReportTimeoutData(topic, state))
|
|
);
|
|
} else {
|
|
warn("No crash reporter available");
|
|
}
|
|
|
|
// To help sorting out bugs, we want to make sure that the
|
|
// call to nsIDebug2.abort points to a guilty client, rather
|
|
// than to AsyncShutdown itself. We pick a client that is
|
|
// still blocking and use its filename/lineNumber,
|
|
// which have been determined during the call to `addBlocker`.
|
|
let filename = "?";
|
|
let lineNumber = -1;
|
|
for (let blocker of this._promiseToBlocker.values()) {
|
|
({ filename, lineNumber } = blocker.getOrigin());
|
|
break;
|
|
}
|
|
lazy.gDebug.abort(filename, lineNumber);
|
|
},
|
|
function onSatisfied() {
|
|
// The promise has been rejected, which means that we have satisfied
|
|
// all completion conditions.
|
|
}
|
|
);
|
|
|
|
promise = promise.then(
|
|
function() {
|
|
timeToCrash.reject();
|
|
} /* No error is possible here*/
|
|
);
|
|
}
|
|
|
|
return promise;
|
|
},
|
|
|
|
_gatherCrashReportTimeoutData(phase, conditions) {
|
|
let data = { phase, conditions };
|
|
if (gBrokenAddBlockers.length) {
|
|
data.brokenAddBlockers = gBrokenAddBlockers;
|
|
}
|
|
return data;
|
|
},
|
|
|
|
_removeBlocker(condition) {
|
|
if (
|
|
!this._waitForMe ||
|
|
!this._promiseToBlocker ||
|
|
!this._conditionToPromise
|
|
) {
|
|
// We have already cleaned up everything.
|
|
return false;
|
|
}
|
|
|
|
let promise = this._conditionToPromise.get(condition);
|
|
if (!promise) {
|
|
// The blocker has already been removed
|
|
return false;
|
|
}
|
|
this._conditionToPromise.delete(condition);
|
|
this._promiseToBlocker.delete(promise);
|
|
return this._waitForMe.delete(promise);
|
|
},
|
|
});
|
|
|
|
// List of well-known phases
|
|
// Ideally, phases should be registered from the component that decides
|
|
// when they start/stop. For compatibility with existing startup/shutdown
|
|
// mechanisms, we register a few phases here.
|
|
|
|
// Parent process
|
|
if (!isContent) {
|
|
AsyncShutdown.profileChangeTeardown = getPhase("profile-change-teardown");
|
|
AsyncShutdown.profileBeforeChange = getPhase("profile-before-change");
|
|
AsyncShutdown.sendTelemetry = getPhase("profile-before-change-telemetry");
|
|
}
|
|
|
|
// Notifications that fire in the parent and content process, but should
|
|
// only have phases in the parent process.
|
|
if (!isContent) {
|
|
AsyncShutdown.quitApplicationGranted = getPhase("quit-application-granted");
|
|
}
|
|
|
|
// Don't add a barrier for content-child-shutdown because this
|
|
// makes it easier to cause shutdown hangs.
|
|
|
|
// All processes
|
|
AsyncShutdown.webWorkersShutdown = getPhase("web-workers-shutdown");
|
|
AsyncShutdown.xpcomWillShutdown = getPhase("xpcom-will-shutdown");
|
|
|
|
AsyncShutdown.Barrier = Barrier;
|
|
|
|
Object.freeze(AsyncShutdown);
|