forked from nodejs/node
/
abort_controller.js
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/
abort_controller.js
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'use strict';
// Modeled very closely on the AbortController implementation
// in https://github.com/mysticatea/abort-controller (MIT license)
const {
ObjectAssign,
ObjectDefineProperties,
ObjectSetPrototypeOf,
ObjectDefineProperty,
SafeFinalizationRegistry,
SafeSet,
Symbol,
SymbolToStringTag,
WeakRef,
} = primordials;
const {
defineEventHandler,
EventTarget,
Event,
kTrustEvent,
kNewListener,
kRemoveListener,
} = require('internal/event_target');
const {
customInspectSymbol,
} = require('internal/util');
const { inspect } = require('internal/util/inspect');
const {
codes: {
ERR_ILLEGAL_CONSTRUCTOR,
ERR_INVALID_THIS,
}
} = require('internal/errors');
const {
validateUint32,
} = require('internal/validators');
const {
DOMException,
} = internalBinding('messaging');
const {
clearTimeout,
setTimeout,
} = require('timers');
const kAborted = Symbol('kAborted');
const kReason = Symbol('kReason');
const kTimeout = Symbol('kTimeout');
const timeOutSignals = new SafeSet();
const clearTimeoutRegistry = new SafeFinalizationRegistry(clearTimeout);
function customInspect(self, obj, depth, options) {
if (depth < 0)
return self;
const opts = ObjectAssign({}, options, {
depth: options.depth === null ? null : options.depth - 1
});
return `${self.constructor.name} ${inspect(obj, opts)}`;
}
function validateAbortSignal(obj) {
if (obj?.[kAborted] === undefined)
throw new ERR_INVALID_THIS('AbortSignal');
}
// Because the AbortSignal timeout cannot be canceled, we don't want the
// presence of the timer alone to keep the AbortSignal from being garbage
// collected if it otherwise no longer accessible. We also don't want the
// timer to keep the Node.js process open on it's own. Therefore, we wrap
// the AbortSignal in a WeakRef and have the setTimeout callback close
// over the WeakRef rather than directly over the AbortSignal, and we unref
// the created timer object. Separately, we add the signal to a
// FinalizerRegistry that will clear the timeout when the signal is gc'd.
function setWeakAbortSignalTimeout(weakRef, delay) {
const timeout = setTimeout(() => {
const signal = weakRef.deref();
if (signal !== undefined) {
timeOutSignals.delete(signal);
abortSignal(
signal,
new DOMException(
'The operation was aborted due to timeout',
'TimeoutError'));
}
}, delay);
timeout.unref();
return timeout;
}
class AbortSignal extends EventTarget {
constructor() {
throw new ERR_ILLEGAL_CONSTRUCTOR();
}
/**
* @type {boolean}
*/
get aborted() {
validateAbortSignal(this);
return !!this[kAborted];
}
/**
* @type {any}
*/
get reason() {
validateAbortSignal(this);
return this[kReason];
}
throwIfAborted() {
if (this.aborted) {
throw this.reason;
}
}
[customInspectSymbol](depth, options) {
return customInspect(this, {
aborted: this.aborted
}, depth, options);
}
/**
* @param {any} reason
* @returns {AbortSignal}
*/
static abort(
reason = new DOMException('This operation was aborted', 'AbortError')) {
return createAbortSignal(true, reason);
}
/**
* @param {number} delay
* @returns {AbortSignal}
*/
static timeout(delay) {
validateUint32(delay, 'delay', true);
const signal = createAbortSignal();
signal[kTimeout] = true;
clearTimeoutRegistry.register(
signal,
setWeakAbortSignalTimeout(new WeakRef(signal), delay));
return signal;
}
[kNewListener](size, type, listener, once, capture, passive, weak) {
super[kNewListener](size, type, listener, once, capture, passive, weak);
if (this[kTimeout] &&
type === 'abort' &&
!this.aborted &&
!weak &&
size === 1) {
// If this is a timeout signal, and we're adding a non-weak abort
// listener, then we don't want it to be gc'd while the listener
// is attached and the timer still hasn't fired. So, we retain a
// strong ref that is held for as long as the listener is registered.
timeOutSignals.add(this);
}
}
[kRemoveListener](size, type, listener, capture) {
super[kRemoveListener](size, type, listener, capture);
if (this[kTimeout] && type === 'abort' && size === 0) {
timeOutSignals.delete(this);
}
}
}
ObjectDefineProperties(AbortSignal.prototype, {
aborted: { enumerable: true }
});
ObjectDefineProperty(AbortSignal.prototype, SymbolToStringTag, {
writable: false,
enumerable: false,
configurable: true,
value: 'AbortSignal',
});
defineEventHandler(AbortSignal.prototype, 'abort');
function createAbortSignal(aborted = false, reason = undefined) {
const signal = new EventTarget();
ObjectSetPrototypeOf(signal, AbortSignal.prototype);
signal[kAborted] = aborted;
signal[kReason] = reason;
return signal;
}
function abortSignal(signal, reason) {
if (signal[kAborted]) return;
signal[kAborted] = true;
signal[kReason] = reason;
const event = new Event('abort', {
[kTrustEvent]: true
});
signal.dispatchEvent(event);
}
// TODO(joyeecheung): V8 snapshot does not support instance member
// initializers for now:
// https://bugs.chromium.org/p/v8/issues/detail?id=10704
const kSignal = Symbol('signal');
function validateAbortController(obj) {
if (obj?.[kSignal] === undefined)
throw new ERR_INVALID_THIS('AbortController');
}
class AbortController {
constructor() {
this[kSignal] = createAbortSignal();
}
/**
* @type {AbortSignal}
*/
get signal() {
validateAbortController(this);
return this[kSignal];
}
/**
* @param {any} reason
*/
abort(reason = new DOMException('This operation was aborted', 'AbortError')) {
validateAbortController(this);
abortSignal(this[kSignal], reason);
}
[customInspectSymbol](depth, options) {
return customInspect(this, {
signal: this.signal
}, depth, options);
}
}
ObjectDefineProperties(AbortController.prototype, {
signal: { enumerable: true },
abort: { enumerable: true }
});
ObjectDefineProperty(AbortController.prototype, SymbolToStringTag, {
writable: false,
enumerable: false,
configurable: true,
value: 'AbortController',
});
module.exports = {
kAborted,
AbortController,
AbortSignal,
};