Remove duplicate mutex implementation

Author: simolus3

sqlite3_web/lib/src/client.dart

@@ -8,6 +8,7 @@ import 'package:stream_channel/stream_channel.dart';
 import 'package:web/web.dart'
     hide Response, Request, FileSystem, Notification, Lock;
 
+import 'locks.dart';
 import 'types.dart';
 import 'channel.dart';
 import 'database.dart';
@@ -329,7 +330,7 @@ final class DatabaseClient implements WebSqlite {
   final DatabaseController _localController;
   final Future<JSAny?> Function(JSAny?) _handleCustomRequest;
 
-  final Lock _startWorkersLock = Lock();
+  final Mutex _startWorkers = Mutex();
   bool _startedWorkers = false;
   WorkerConnection? _connectionToDedicated;
   WorkerConnection? _connectionToShared;
@@ -347,7 +348,7 @@ final class DatabaseClient implements WebSqlite {
             });
 
   Future<void> startWorkers() {
-    return _startWorkersLock.synchronized(() async {
+    return _startWorkers.withCriticalSection(() async {
       if (_startedWorkers) {
         return;
       }
@@ -406,7 +407,7 @@ final class DatabaseClient implements WebSqlite {
   }
 
   Future<WorkerConnection> _connectToDedicatedInShared() {
-    return _startWorkersLock.synchronized(() async {
+    return _startWorkers.withCriticalSection(() async {
       if (_connectionToDedicatedInShared case final conn?) {
         return conn;
       }
@@ -421,7 +422,7 @@ final class DatabaseClient implements WebSqlite {
   }
 
   Future<WorkerConnection> _connectToLocal() async {
-    return _startWorkersLock.synchronized(() async {
+    return _startWorkers.withCriticalSection(() async {
       if (_connectionToLocal case final conn?) {
         return conn;
       }

sqlite3_web/lib/src/shared.dart

@@ -64,31 +64,6 @@ Future<void> deleteDatabaseInIndexedDb(String databaseName) async {
   await idb.deleteDatabase(databaseName).complete<JSAny?>();
 }
 
-/// A single asynchronous lock implemented by future-chaining.
-class Lock {
-  Future<void>? _last;
-
-  /// Waits for previous [synchronized]-calls on this [Lock] to complete, and
-  /// then calls [block] before further [synchronized] calls are allowed.
-  Future<T> synchronized<T>(FutureOr<T> Function() block) {
-    final previous = _last;
-    // This completer may not be sync: It must complete just after
-    // callBlockAndComplete completes.
-    final blockCompleted = Completer<void>();
-    _last = blockCompleted.future;
-
-    Future<T> callBlockAndComplete() {
-      return Future.sync(block).whenComplete(blockCompleted.complete);
-    }
-
-    if (previous != null) {
-      return previous.then((_) => callBlockAndComplete());
-    } else {
-      return callBlockAndComplete();
-    }
-  }
-}
-
 /// Collects all drift OPFS databases.
 Future<List<String>> opfsDatabases() async {
   final storage = storageManager;

sqlite3_web/lib/src/worker.dart

@@ -657,7 +657,7 @@ final class WorkerRunner {
   Future<WasmSqlite3>? _sqlite3;
   Uri? _wasmUri;
 
-  final Lock _compatibilityCheckLock = Lock();
+  final Mutex _compatibilityCheck = Mutex();
   CompatibilityResult? _compatibilityResult;
 
   /// For shared workers, a dedicated inner worker allowing tabs to connect to
@@ -696,7 +696,7 @@ final class WorkerRunner {
   }
 
   Future<CompatibilityResult> checkCompatibility(CompatibilityCheck check) {
-    return _compatibilityCheckLock.synchronized(() async {
+    return _compatibilityCheck.withCriticalSection(() async {
       if (_compatibilityResult != null) {
         // todo: We may have to update information about existing databases
         // as they come and go