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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,
/**
* An implementation of nsIAsyncShutdown* based on AsyncShutdown.sys.mjs
*/
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
AsyncShutdown: "resource://gre/modules/AsyncShutdown.sys.mjs",
});
/**
* Conversion between nsIPropertyBags and JS values.
* This uses a conservative approach to avoid losing data and doesn't throw.
* Don't use this if you need perfect serialization and deserialization.
*/
class PropertyBagConverter {
/**
* When the js value to convert is a primitive, it is stored in the property
* bag under a key with this name.
*/
get primitiveProperty() {
return "PropertyBagConverter_primitive";
}
/**
* Converts from a PropertyBag to a JS value.
* @param {nsIPropertyBag} bag The PropertyBag to convert.
* @returns {jsval} A JS value.
*/
propertyBagToJsValue(bag) {
if (!(bag instanceof Ci.nsIPropertyBag)) {
return null;
}
let result = {};
for (let { name, value: property } of bag.enumerator) {
let value = this.#toValue(property);
if (name == this.primitiveProperty) {
return value;
}
result[name] = value;
}
return result;
}
#toValue(property) {
if (property instanceof Ci.nsIPropertyBag) {
return this.propertyBagToJsValue(property);
}
if (["number", "boolean"].includes(typeof property)) {
return property;
}
try {
return JSON.parse(property);
} catch (ex) {
// Not JSON.
}
return property;
}
/**
* Converts from a JS value to a PropertyBag.
* @param {jsval} val JS value to convert.
* @returns {nsIPropertyBag} A PropertyBag.
* @note function is converted to "(function)" and undefined to null.
*/
jsValueToPropertyBag(val) {
let bag = Cc["@mozilla.org/hash-property-bag;1"].createInstance(
Ci.nsIWritablePropertyBag
);
if (val && typeof val == "object") {
for (let k of Object.keys(val)) {
bag.setProperty(k, this.#fromValue(val[k]));
}
} else {
bag.setProperty(this.primitiveProperty, this.#fromValue(val));
}
return bag;
}
#fromValue(value) {
if (typeof value == "function") {
return "(function)";
}
if (value === undefined) {
value = null;
}
if (["number", "boolean", "string"].includes(typeof value)) {
return value;
}
return JSON.stringify(value);
}
}
/**
* Construct an instance of nsIAsyncShutdownClient from a
* AsyncShutdown.Barrier client.
*
* @param {object} moduleClient A client, as returned from the `client`
* property of an instance of `AsyncShutdown.Barrier`. This client will
* serve as back-end for methods `addBlocker` and `removeBlocker`.
* @constructor
*/
function nsAsyncShutdownClient(moduleClient) {
if (!moduleClient) {
throw new TypeError("nsAsyncShutdownClient expects one argument");
}
this._moduleClient = moduleClient;
this._byXpcomBlocker = new Map();
}
nsAsyncShutdownClient.prototype = {
get jsclient() {
return this._moduleClient;
},
get name() {
return this._moduleClient.name;
},
get isClosed() {
return this._moduleClient.isClosed;
},
addBlocker(
/* nsIAsyncShutdownBlocker*/ xpcomBlocker,
fileName,
lineNumber,
stack
) {
// We need a Promise-based function with the same behavior as
// `xpcomBlocker`. Furthermore, to support `removeBlocker`, we
// need to ensure that we always get the same Promise-based
// function if we call several `addBlocker`/`removeBlocker` several
// times with the same `xpcomBlocker`.
if (this._byXpcomBlocker.has(xpcomBlocker)) {
throw new Error(
`We have already registered the blocker (${xpcomBlocker.name})`
);
}
// Ideally, this should be done with a WeakMap() with xpcomBlocker
// as a key, but XPCWrappedNative objects cannot serve as WeakMap keys, see
const moduleBlocker = () =>
new Promise(
// This promise is never resolved. By opposition to AsyncShutdown
// blockers, `nsIAsyncShutdownBlocker`s are always lifted by calling
// `removeBlocker`.
() => xpcomBlocker.blockShutdown(this)
);
this._byXpcomBlocker.set(xpcomBlocker, moduleBlocker);
this._moduleClient.addBlocker(xpcomBlocker.name, moduleBlocker, {
fetchState: () =>
new PropertyBagConverter().propertyBagToJsValue(xpcomBlocker.state),
filename: fileName,
lineNumber,
stack,
});
},
removeBlocker(xpcomBlocker) {
let moduleBlocker = this._byXpcomBlocker.get(xpcomBlocker);
if (!moduleBlocker) {
return false;
}
this._byXpcomBlocker.delete(xpcomBlocker);
return this._moduleClient.removeBlocker(moduleBlocker);
},
QueryInterface: ChromeUtils.generateQI(["nsIAsyncShutdownClient"]),
};
/**
* Construct an instance of nsIAsyncShutdownBarrier from an instance
* of AsyncShutdown.Barrier.
*
* @param {object} moduleBarrier an instance if
* `AsyncShutdown.Barrier`. This instance will serve as back-end for
* all methods.
* @constructor
*/
function nsAsyncShutdownBarrier(moduleBarrier) {
this._client = new nsAsyncShutdownClient(moduleBarrier.client);
this._moduleBarrier = moduleBarrier;
}
nsAsyncShutdownBarrier.prototype = {
get state() {
return new PropertyBagConverter().jsValueToPropertyBag(
this._moduleBarrier.state
);
},
get client() {
return this._client;
},
wait(onReady) {
this._moduleBarrier.wait().then(() => {
onReady.done();
});
// By specification, _moduleBarrier.wait() cannot reject.
},
QueryInterface: ChromeUtils.generateQI(["nsIAsyncShutdownBarrier"]),
};
export function nsAsyncShutdownService() {
// Cache for the getters
for (let _k of [
// Parent process
"profileBeforeChange",
"profileChangeTeardown",
"quitApplicationGranted",
"sendTelemetry",
// Child processes
"contentChildShutdown",
// All processes
"webWorkersShutdown",
"xpcomWillShutdown",
]) {
let k = _k;
Object.defineProperty(this, k, {
configurable: true,
get() {
delete this[k];
let wrapped = lazy.AsyncShutdown[k]; // May be undefined, if we're on the wrong process.
let result = wrapped ? new nsAsyncShutdownClient(wrapped) : undefined;
Object.defineProperty(this, k, {
value: result,
});
return result;
},
});
}
// Hooks for testing purpose
this.wrappedJSObject = {
_propertyBagConverter: PropertyBagConverter,
};
}
nsAsyncShutdownService.prototype = {
makeBarrier(name) {
return new nsAsyncShutdownBarrier(new lazy.AsyncShutdown.Barrier(name));
},
QueryInterface: ChromeUtils.generateQI(["nsIAsyncShutdownService"]),
};