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/*
* Copyright 2022 Codeblog Corp. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
function onAsyncIterator(emitter, event, options) {
"use strict";
var { AbortSignal, Symbol, Number, Error } = globalThis;
var AbortError = class AbortError extends Error {
constructor(message = "The operation was aborted", options = void 0) {
if (options !== void 0 && typeof options !== "object") {
throw new Error(`Invalid AbortError options:\n\n${JSON.stringify(options, null, 2)}`);
}
super(message, options);
this.code = "ABORT_ERR";
this.name = "AbortError";
}
};
if (@isUndefinedOrNull(emitter)) @throwTypeError("emitter is required");
// TODO: Do a more accurate check
if (!(@isObject(emitter) && @isCallable(emitter.emit) && @isCallable(emitter.on)))
@throwTypeError("emitter must be an EventEmitter");
if (@isUndefinedOrNull(options)) options = {};
// Parameters validation
var signal = options.signal;
if (signal !== undefined && (!@isObject(signal) || !(signal instanceof AbortSignal)))
@throwTypeError("options.signal must be an AbortSignal");
if (signal?.aborted) {
// TODO: Make this a builtin
throw new AbortError(@undefined, { cause: signal?.reason });
}
var highWatermark = options.highWatermark ?? Number.MAX_SAFE_INTEGER;
if (highWatermark < 1)
@throwRangeError("options.highWatermark must be >= 1");
var lowWatermark = options.lowWatermark ?? 1;
if (lowWatermark < 1)
@throwRangeError("options.lowWatermark must be >= 1");
var unconsumedEvents = @createFIFO();
var unconsumedPromises = @createFIFO();
var paused = false;
var error = null;
var finished = false;
var size = 0;
var listeners = [];
function abortListener() {
errorHandler(new AbortError(@undefined, { cause: signal?.reason }));
}
function eventHandler(value) {
if (unconsumedPromises.isEmpty()) {
size++;
if (!paused && size > highWatermark) {
paused = true;
emitter.pause();
}
unconsumedEvents.push(value);
} else unconsumedPromises.shift().@resolve.@call(@undefined, [value]);
}
function closeHandler() {
removeAllListeners();
finished = true;
while (!unconsumedPromises.isEmpty()) {
const promise = unconsumedPromises.shift();
promise.@resolve.@call(@undefined, [@undefined]);
}
return @createFulfilledPromise([@undefined]);
}
function errorHandler(err) {
if (unconsumedPromises.isEmpty()) error = err;
else unconsumedPromises.shift().@reject.@call(@undefined, err);
closeHandler();
}
function addEventListener(emitter, event, handler) {
emitter.on(event, handler);
listeners.push([emitter, event, handler]);
}
function removeAllListeners() {
while (listeners.length > 0) {
var entry = listeners.pop();
var [emitter, event, handler] = entry;
emitter.off(event, handler);
}
}
var createIterator = async function* NodeEventsOnAsyncIterator() {
// First, we consume all unread events
try {
while (true) {
// Go through queued events
while (size) {
const value = unconsumedEvents.shift();
size--;
if (paused && size < lowWatermark) {
emitter.resume();
paused = false;
break;
}
yield @createFulfilledPromise([value]);
}
// Check if error happened before yielding anything
// This happens one time if at all, because after 'error'
// we stop listening
if (error) {
throw error;
}
// If the iterator is finished, break
if (finished) break;
// Wait until an event happens
var nextEventPromiseCapability = @newPromiseCapability(@Promise);
unconsumedPromises.push(nextEventPromiseCapability);
yield nextEventPromiseCapability.@promise;
}
} finally {
closeHandler();
}
};
// Adding event handlers
addEventListener(emitter, event, eventHandler);
if (event !== "error" && typeof emitter.on === "function") {
addEventListener(emitter, "error", errorHandler);
}
var closeEvents = options?.close;
if (closeEvents?.length) {
for (var i = 0; i < closeEvents.length; i++) {
addEventListener(emitter, closeEvents[i], closeHandler);
}
}
if (signal) signal.addEventListener("abort", abortListener, { once: true });
var iterator = createIterator();
@Object.defineProperties(iterator, {
return: {
value: () => closeHandler(),
},
throw: {
value: (err) => {
if (!err || !(err instanceof Error)) {
throw new TypeError("EventEmitter.AsyncIterator must be called with an error");
}
errorHandler(err);
},
},
[Symbol.asyncIterator]: {
value: () => iterator,
},
});
return iterator;
}
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