Initial commit

2026-07-14 11:11:36 +08:00
commit 656499cf94
604 changed files with 119518 additions and 0 deletions
@@ -0,0 +1,28 @@
+import 'dart:async';
+
+class CancelledException implements Exception {
+  final String? reason;
+  const CancelledException([this.reason]);
+  @override
+  String toString() =>
+      reason == null ? 'CancelledException' : 'CancelledException: $reason';
+}
+
+class CancellationToken {
+  final Completer<void> _completer = Completer<void>();
+  String? _reason;
+
+  bool get isCancelled => _completer.isCompleted;
+  String? get reason => _reason;
+  Future<void> get whenCancelled => _completer.future;
+
+  void cancel([String? reason]) {
+    if (_completer.isCompleted) return;
+    _reason = reason;
+    _completer.complete();
+  }
+
+  void throwIfCancelled() {
+    if (isCancelled) throw CancelledException(_reason);
+  }
+}