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Mypal/toolkit/components/asyncshutdown/AsyncShutdown.jsm

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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/. */
/**
* Managing safe shutdown of asynchronous services.
*
* Firefox shutdown is composed of phases that take place
* sequentially. Typically, each shutdown phase removes some
* capabilities from the application. For instance, at the end of
* phase profileBeforeChange, no service is permitted to write to the
* profile directory (with the exception of Telemetry). Consequently,
* if any service has requested I/O to the profile directory before or
* during phase profileBeforeChange, the system must be informed that
* these requests need to be completed before the end of phase
* profileBeforeChange. Failing to inform the system of this
* requirement can (and has been known to) cause data loss.
*
* Example: At some point during shutdown, the Add-On Manager needs to
* ensure that all add-ons have safely written their data to disk,
* before writing its own data. Since the data is saved to the
* profile, this must be completed during phase profileBeforeChange.
*
* AsyncShutdown.profileBeforeChange.addBlocker(
* "Add-on manager: shutting down",
* function condition() {
* // Do things.
* // Perform I/O that must take place during phase profile-before-change
* return promise;
* }
* });
*
* In this example, function |condition| will be called at some point
* during phase profileBeforeChange and phase profileBeforeChange
* itself is guaranteed to not terminate until |promise| is either
* resolved or rejected.
*/
"use strict";
const Cu = Components.utils;
const Cc = Components.classes;
const Ci = Components.interfaces;
Cu.import("resource://gre/modules/XPCOMUtils.jsm", this);
Cu.import("resource://gre/modules/Services.jsm", this);
XPCOMUtils.defineLazyModuleGetter(this, "Promise",
"resource://gre/modules/Promise.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "PromiseUtils",
"resource://gre/modules/PromiseUtils.jsm");
XPCOMUtils.defineLazyModuleGetter(this, "Task",
"resource://gre/modules/Task.jsm");
XPCOMUtils.defineLazyServiceGetter(this, "gDebug",
"@mozilla.org/xpcom/debug;1", "nsIDebug2");
Object.defineProperty(this, "gCrashReporter", {
get: function() {
delete this.gCrashReporter;
try {
let reporter = Cc["@mozilla.org/xre/app-info;1"].
getService(Ci.nsICrashReporter);
return this.gCrashReporter = reporter;
} catch (ex) {
return this.gCrashReporter = null;
}
},
configurable: true
});
// `true` if this is a content process, `false` otherwise.
// It would be nicer to go through `Services.appInfo`, but some tests need to be
// able to replace that field with a custom implementation before it is first
// called.
const isContent = Cc["@mozilla.org/xre/app-info;1"].getService(Ci.nsIXULRuntime).processType == Ci.nsIXULRuntime.PROCESS_TYPE_CONTENT;
// Display timeout warnings after 10 seconds
const DELAY_WARNING_MS = 10 * 1000;
// Crash the process if shutdown is really too long
// (allowing for sleep).
const PREF_DELAY_CRASH_MS = "toolkit.asyncshutdown.crash_timeout";
var DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS,
60 * 1000); // One minute
Services.prefs.addObserver(PREF_DELAY_CRASH_MS, function() {
DELAY_CRASH_MS = Services.prefs.getIntPref(PREF_DELAY_CRASH_MS);
}, false);
/**
* A set of Promise that supports waiting.
*
* Promise items may be added or removed during the wait. The wait will
* resolve once all Promise items have been resolved or removed.
*/
function PromiseSet() {
/**
* key: the Promise passed pass the client of the `PromiseSet`.
* value: an indirection on top of `key`, as an object with
* the following fields:
* - indirection: a Promise resolved if `key` is resolved or
* if `resolve` is called
* - resolve: a function used to resolve the indirection.
*/
this._indirections = new Map();
}
PromiseSet.prototype = {
/**
* Wait until all Promise have been resolved or removed.
*
* Note that calling `wait()` causes Promise to be removed from the
* Set once they are resolved.
*
* @return {Promise} Resolved once all Promise have been resolved or removed,
* or rejected after at least one Promise has rejected.
*/
wait: function() {
// Pick an arbitrary element in the map, if any exists.
let entry = this._indirections.entries().next();
if (entry.done) {
// No indirections left, we are done.
return Promise.resolve();
}
let [, indirection] = entry.value;
let promise = indirection.promise;
promise = promise.then(() =>
// At this stage, the entry has been cleaned up.
this.wait()
);
return promise;
},
/**
* Add a new Promise to the set.
*
* Calls to wait (including ongoing calls) will only return once
* `key` has either resolved or been removed.
*/
add: function(key) {
this._ensurePromise(key);
let indirection = PromiseUtils.defer();
key.then(
x => {
// Clean up immediately.
// This needs to be done before the call to `resolve`, otherwise
// `wait()` may loop forever.
this._indirections.delete(key);
indirection.resolve(x);
},
err => {
this._indirections.delete(key);
indirection.reject(err);
});
this._indirections.set(key, indirection);
},
/**
* Remove a Promise from the set.
*
* Calls to wait (including ongoing calls) will ignore this promise,
* unless it is added again.
*/
delete: function(key) {
this._ensurePromise(key);
let value = this._indirections.get(key);
if (!value) {
return false;
}
this._indirections.delete(key);
value.resolve();
return true;
},
_ensurePromise: function(key) {
if (!key || typeof key != "object") {
throw new Error("Expected an object");
}
if ((!("then" in key)) || typeof key.then != "function") {
throw new Error("Expected a Promise");
}
},
};
/**
* Display a warning.
*
* As this code is generally used during shutdown, there are chances
* that the UX will not be available to display warnings on the
* console. We therefore use dump() rather than Cu.reportError().
*/
function log(msg, prefix = "", error = null) {
try {
dump(prefix + msg + "\n");
if (error) {
dump(prefix + error + "\n");
if (typeof error == "object" && "stack" in error) {
dump(prefix + error.stack + "\n");
}
}
} catch (ex) {
dump("INTERNAL ERROR in AsyncShutdown: cannot log message.\n");
}
}
const PREF_DEBUG_LOG = "toolkit.asyncshutdown.log";
var DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG, false);
Services.prefs.addObserver(PREF_DEBUG_LOG, function() {
DEBUG_LOG = Services.prefs.getBoolPref(PREF_DEBUG_LOG);
}, false);
function debug(msg, error=null) {
if (DEBUG_LOG) {
log(msg, "DEBUG: ", error);
}
}
function warn(msg, error = null) {
log(msg, "WARNING: ", error);
}
function fatalerr(msg, error = null) {
log(msg, "FATAL ERROR: ", error);
}
// Utility function designed to get the current state of execution
// of a blocker.
// We are a little paranoid here to ensure that in case of evaluation
// error we do not block the AsyncShutdown.
function safeGetState(fetchState) {
if (!fetchState) {
return "(none)";
}
let data, string;
try {
// Evaluate fetchState(), normalize the result into something that we can
// safely stringify or upload.
let state = fetchState();
if (!state) {
return "(none)";
}
string = JSON.stringify(state);
data = JSON.parse(string);
// Simplify the rest of the code by ensuring that we can simply
// concatenate the result to a message.
if (data && typeof data == "object") {
data.toString = function() {
return string;
};
}
return data;
} catch (ex) {
// Make sure that this causes test failures
Promise.reject(ex);
if (string) {
return string;
}
try {
return "Error getting state: " + ex + " at " + ex.stack;
} catch (ex2) {
return "Error getting state but could not display error";
}
}
}
/**
* Countdown for a given duration, skipping beats if the computer is too busy,
* sleeping or otherwise unavailable.
*
* @param {number} delay An approximate delay to wait in milliseconds (rounded
* up to the closest second).
*
* @return Deferred
*/
function looseTimer(delay) {
let DELAY_BEAT = 1000;
let timer = Cc["@mozilla.org/timer;1"].createInstance(Ci.nsITimer);
let beats = Math.ceil(delay / DELAY_BEAT);
let deferred = Promise.defer();
timer.initWithCallback(function() {
if (beats <= 0) {
deferred.resolve();
}
--beats;
}, DELAY_BEAT, Ci.nsITimer.TYPE_REPEATING_PRECISE_CAN_SKIP);
// Ensure that the timer is both canceled once we are done with it
// and not garbage-collected until then.
deferred.promise.then(() => timer.cancel(), () => timer.cancel());
return deferred;
}
/**
* Given an nsIStackFrame object, find the caller filename, line number,
* and stack if necessary, and return them as an object.
*
* @param {nsIStackFrame} topFrame Top frame of the call stack.
* @param {string} filename Pre-supplied filename or null if unknown.
* @param {number} lineNumber Pre-supplied line number or null if unknown.
* @param {string} stack Pre-supplied stack or null if unknown.
*
* @return object
*/
function getOrigin(topFrame, filename = null, lineNumber = null, stack = null) {
try {
// Determine the filename and line number of the caller.
let frame = topFrame;
for (; frame && frame.filename == topFrame.filename; frame = frame.caller) {
// Climb up the stack
}
if (filename == null) {
filename = frame ? frame.filename : "?";
}
if (lineNumber == null) {
lineNumber = frame ? frame.lineNumber : 0;
}
if (stack == null) {
// Now build the rest of the stack as a string, using Task.jsm's rewriting
// to ensure that we do not lose information at each call to `Task.spawn`.
let frames = [];
while (frame != null) {
frames.push(frame.filename + ":" + frame.name + ":" + frame.lineNumber);
frame = frame.caller;
}
stack = Task.Debugging.generateReadableStack(frames.join("\n")).split("\n");
}
return {
filename: filename,
lineNumber: lineNumber,
stack: stack,
};
} catch (ex) {
return {
filename: "<internal error: could not get origin>",
lineNumber: -1,
stack: "<internal error: could not get origin>",
}
}
}
this.EXPORTED_SYMBOLS = ["AsyncShutdown"];
/**
* {string} topic -> phase
*/
var gPhases = new Map();
this.AsyncShutdown = {
/**
* Access function getPhase. For testing purposes only.
*/
get _getPhase() {
let accepted = Services.prefs.getBoolPref("toolkit.asyncshutdown.testing", false);
if (accepted) {
return getPhase;
}
return undefined;
}
};
/**
* Register a new phase.
*
* @param {string} topic The notification topic for this Phase.
* @see {https://developer.mozilla.org/en-US/docs/Observer_Notifications}
*/
function getPhase(topic) {
let phase = gPhases.get(topic);
if (phase) {
return phase;
}
let spinner = new Spinner(topic);
phase = Object.freeze({
/**
* Register a blocker for the completion of a phase.
*
* @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.
*
* Examples:
* AsyncShutdown.profileBeforeChange.addBlocker("Module: just a promise",
* promise); // profileBeforeChange will not complete until
* // promise is resolved or rejected
*
* AsyncShutdown.profileBeforeChange.addBlocker("Module: a callback",
* function callback() {
* // ...
* // Execute this code during profileBeforeChange
* return promise;
* // profileBeforeChange will not complete until promise
* // is resolved or rejected
* });
*
* AsyncShutdown.profileBeforeChange.addBlocker("Module: trivial callback",
* function callback() {
* // ...
* // Execute this code during profileBeforeChange
* // No specific guarantee about completion of profileBeforeChange
* });
*/
addBlocker: function(name, condition, details = null) {
spinner.addBlocker(name, condition, details);
},
/**
* 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: function(condition) {
return spinner.removeBlocker(condition);
},
get name() {
return spinner.name;
},
/**
* 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, false);
}
Spinner.prototype = {
/**
* Register a new condition for this phase.
*
* See the documentation of `addBlocker` in property `client`
* of instances of `Barrier`.
*/
addBlocker: function(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: function(condition) {
return this._barrier.client.removeBlocker(condition);
},
get name() {
return this._barrier.client.name;
},
// nsIObserver.observe
observe: function() {
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;
/**
* 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") {
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") {
throw new TypeError("Expected an object as third argument to `addBlocker`, got " + details);
}
if (!this._waitForMe) {
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 }`);
// Normalize the details
let fetchState = details.fetchState || null;
if (fetchState != null && typeof fetchState != "function") {
throw new TypeError("Expected a function for option `fetchState`");
}
let filename = details.filename || null;
let lineNumber = details.lineNumber || null;
let stack = details.stack || null;
// 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.then(null, 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: trigger,
promise: promise,
name: name,
fetchState: 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);
}
};
}
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: name,
state: safeGetState(fetchState),
filename: filename,
lineNumber: lineNumber,
stack: 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: function(options = {}) {
// This method only implements caching on top of _wait()
if (this._promise) {
return this._promise;
}
return this._promise = this._wait(options);
},
_wait: function(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();
promise = promise.then(null, 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(
function onTimeout() {
// 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 (gCrashReporter && gCrashReporter.enabled) {
let data = {
phase: topic,
conditions: state
};
gCrashReporter.annotateCrashReport("AsyncShutdownTimeout",
JSON.stringify(data));
} 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;
}
gDebug.abort(filename, lineNumber);
}.bind(this),
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;
},
_removeBlocker: function(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) {
this.AsyncShutdown.profileChangeTeardown = getPhase("profile-change-teardown");
this.AsyncShutdown.profileBeforeChange = getPhase("profile-before-change");
this.AsyncShutdown.placesClosingInternalConnection = getPhase("places-will-close-connection");
this.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) {
this.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
this.AsyncShutdown.webWorkersShutdown = getPhase("web-workers-shutdown");
this.AsyncShutdown.xpcomWillShutdown = getPhase("xpcom-will-shutdown");
this.AsyncShutdown.Barrier = Barrier;
Object.freeze(this.AsyncShutdown);
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