Initial commit

node_modules/execa/lib/ipc/graceful.js

@@ -0,0 +1,72 @@
+import {scheduler} from 'node:timers/promises';
+import {sendOneMessage} from './send.js';
+import {getIpcEmitter} from './forward.js';
+import {validateConnection, getAbortDisconnectError, throwOnMissingParent} from './validation.js';
+
+// Send an IPC message so the subprocess performs a graceful termination
+export const sendAbort = (subprocess, message) => {
+	const methodName = 'cancelSignal';
+	validateConnection(methodName, false, subprocess.connected);
+	return sendOneMessage({
+		anyProcess: subprocess,
+		methodName,
+		isSubprocess: false,
+		wrappedMessage: {type: GRACEFUL_CANCEL_TYPE, message},
+		message,
+	});
+};
+
+// When the signal is being used, start listening for incoming messages.
+// Unbuffering messages takes one microtask to complete, so this must be async.
+export const getCancelSignal = async ({anyProcess, channel, isSubprocess, ipc}) => {
+	await startIpc({
+		anyProcess,
+		channel,
+		isSubprocess,
+		ipc,
+	});
+	return cancelController.signal;
+};
+
+const startIpc = async ({anyProcess, channel, isSubprocess, ipc}) => {
+	if (cancelListening) {
+		return;
+	}
+
+	cancelListening = true;
+
+	if (!ipc) {
+		throwOnMissingParent();
+		return;
+	}
+
+	if (channel === null) {
+		abortOnDisconnect();
+		return;
+	}
+
+	getIpcEmitter(anyProcess, channel, isSubprocess);
+	await scheduler.yield();
+};
+
+let cancelListening = false;
+
+// Reception of IPC message to perform a graceful termination
+export const handleAbort = wrappedMessage => {
+	if (wrappedMessage?.type !== GRACEFUL_CANCEL_TYPE) {
+		return false;
+	}
+
+	cancelController.abort(wrappedMessage.message);
+	return true;
+};
+
+const GRACEFUL_CANCEL_TYPE = 'execa:ipc:cancel';
+
+// When the current process disconnects early, the subprocess `cancelSignal` is aborted.
+// Otherwise, the signal would never be able to be aborted later on.
+export const abortOnDisconnect = () => {
+	cancelController.abort(getAbortDisconnectError());
+};
+
+const cancelController = new AbortController();