Signals And Terminal

import 'dart:async';
import 'dart:io';
import 'package:async/async.dart';

/// Listens for process termination signals across Windows, macOS, and Linux.
Stream<ProcessSignal> watchTerminationSignals() {
  if (Platform.isWindows) {
    return ProcessSignal.sigint.watch();
  }
  return StreamGroup.merge([
    ProcessSignal.sigint.watch(),
    ProcessSignal.sigterm.watch(),
  ]);
}

import 'dart:io';

void enableInteractiveMode() {
  // Defensive guard: only configure terminal modes if standard input is an interactive TTY.
  if (!stdin.hasTerminal) return;
  stdin.echoMode = false;
  stdin.lineMode = false;

  // Ensure terminal state is synchronously restored on Ctrl+C.
  final sub = ProcessSignal.sigint.watch().listen((_) {
    restoreTerminal();
    // Exiting with 128 + SIGINT (2) = 130 is the standard POSIX protocol
    // for asynchronous signal handlers to communicate signal interruption to the host shell.
    exit(130);
  });

  try {
    // Run interactive loop...
  } finally {
    sub.cancel();
    restoreTerminal();
  }
}

void restoreTerminal() {
  if (stdin.hasTerminal) {
    stdin.lineMode = true;
    stdin.echoMode = true;
  }
}

void showCursor() {
  if (useAnsi) {
    stdout.write('\x1B[?25h');
  }
}

/// Canonical ANSI support check respecting NO_COLOR standards.
bool get useAnsi =>
    stdout.hasTerminal &&
    stdout.supportsAnsiEscapes &&
    !Platform.environment.containsKey('NO_COLOR');

import 'dart:io';

Future<void> safeWriteln(String line) async {
  try {
    stdout.writeln(line);
  } on SocketException catch (e) {
    // EPIPE / Broken pipe: downstream closed standard input.
    if (e.osError?.errorCode == 32 || e.message.contains('Broken pipe')) {
      await stdout.close().catchError((_) {});
      // In a bulk streaming context, calling exit(0) immediately stops the
      // producer loop when downstream has closed its pipe.
      exit(0);
    }
    rethrow;
  }
}