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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
const core = globalThis.Deno.core;
const ops = core.ops;
const primordials = globalThis.__bootstrap.primordials;
const {
SafeSet,
SafeSetIterator,
SetPrototypeAdd,
SetPrototypeDelete,
TypeError,
} = primordials;
function bindSignal(signo) {
return ops.op_signal_bind(signo);
}
function pollSignal(rid) {
const promise = core.opAsync("op_signal_poll", rid);
core.unrefOpPromise(promise);
return promise;
}
function unbindSignal(rid) {
ops.op_signal_unbind(rid);
}
// Stores signal listeners and resource data. This has type of
// `Record<string, { rid: number | undefined, listeners: Set<() => void> }`
const signalData = {};
/** Gets the signal handlers and resource data of the given signal */
function getSignalData(signo) {
return signalData[signo] ??
(signalData[signo] = { rid: undefined, listeners: new SafeSet() });
}
function checkSignalListenerType(listener) {
if (typeof listener !== "function") {
throw new TypeError(
`Signal listener must be a function. "${typeof listener}" is given.`,
);
}
}
function addSignalListener(signo, listener) {
checkSignalListenerType(listener);
const sigData = getSignalData(signo);
SetPrototypeAdd(sigData.listeners, listener);
if (!sigData.rid) {
// If signal resource doesn't exist, create it.
// The program starts listening to the signal
sigData.rid = bindSignal(signo);
loop(sigData);
}
}
function removeSignalListener(signo, listener) {
checkSignalListenerType(listener);
const sigData = getSignalData(signo);
SetPrototypeDelete(sigData.listeners, listener);
if (sigData.listeners.size === 0 && sigData.rid) {
unbindSignal(sigData.rid);
sigData.rid = undefined;
}
}
async function loop(sigData) {
while (sigData.rid) {
if (await pollSignal(sigData.rid)) {
return;
}
for (const listener of new SafeSetIterator(sigData.listeners)) {
listener();
}
}
}
export { addSignalListener, removeSignalListener };
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