pre work for web support: bindings separation, native preparations

ffigen.yaml

@@ -1,10 +1,10 @@
 # Run with `flutter pub run ffigen --config ffigen_linux.yaml`.
-name: StockfishChessEngineBindings
+name: StockfishChessEngineCBindings
 description: |
   Bindings for `src/stockfish.h`.
 
   Regenerate bindings with `dart run ffigen --config ffigen.yaml`.
-output: "lib/stockfish_bindings_generated.dart"
+output: "lib/stockfish_c_bindings_generated.dart"
 headers:
   entry-points:
     - "src/stockfish.h"

lib/stockfish.dart

@@ -1,75 +1,27 @@
-// Using code from https://github.com/ArjanAswal/Stockfish/blob/master/lib/src/stockfish.dart
-
-import 'dart:async';
-import 'dart:ffi';
-import 'dart:io';
-import 'dart:convert';
-import 'dart:isolate';
-import 'dart:developer' as developer;
-
 import 'package:flutter/foundation.dart';
-import 'package:ffi/ffi.dart';
+import 'package:flutter_stockfish_plugin/stockfish_bindings.dart';
+import 'package:flutter_stockfish_plugin/stockfish_native_bindings.dart'
+    if (dart.library.html) 'package:flutter_stockfish_plugin/stockfish_web_bindings.dart';
+import 'package:flutter_stockfish_plugin/stockfish_state.dart';
 
-import 'stockfish_bindings_generated.dart';
-import 'stockfish_state.dart';
+final StockfishChessEngineAbstractBindings _bindings =
+    StockfishChessEngineBindings();
 
-const String _libName = 'flutter_stockfish_plugin';
-//const String _releaseType = kDebugMode ? 'Debug' : 'Release';
-
-/// The dynamic library in which the symbols for [StockfishChessEngineBindings] can be found.
-final DynamicLibrary _dylib = () {
-  if (Platform.isMacOS || Platform.isIOS) {
-    return DynamicLibrary.open('$_libName.framework/$_libName');
-  }
-  if (Platform.isAndroid || Platform.isLinux) {
-    return DynamicLibrary.open('lib$_libName.so');
-  }
-  if (Platform.isWindows) {
-    return DynamicLibrary.open('$_libName.dll');
-  }
-  throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
-}();
-
-/// The bindings to the native functions in [_dylib].
-final StockfishChessEngineBindings _bindings =
-    StockfishChessEngineBindings(_dylib);
-
-/// A wrapper for C++ engine.
 class Stockfish {
-  final Completer<Stockfish>? completer;
+  final _state = StockfishStateClass();
 
-  final _state = _StockfishState();
-  final _stdoutController = StreamController<String>.broadcast();
-  final _mainPort = ReceivePort();
-  final _stdoutPort = ReceivePort();
-
-  late StreamSubscription _mainSubscription;
-  late StreamSubscription _stdoutSubscription;
-
-  Stockfish._({this.completer}) {
-    _mainSubscription =
-        _mainPort.listen((message) => _cleanUp(message is int ? message : 1));
-    _stdoutSubscription = _stdoutPort.listen((message) {
-      if (message is String) {
-        _stdoutController.sink.add(message);
-      } else {
-        developer.log('The stdout isolate sent $message', name: 'Stockfish');
-      }
+  Stockfish._() {
+    _state.setValue(StockfishState.starting);
+    _bindings.stockfishMain(() {
+      _state.setValue(StockfishState.ready);
+    }).then((exitCode) {
+      _state.setValue(
+          exitCode == 0 ? StockfishState.disposed : StockfishState.error);
+      _instance = null;
+    }, onError: (error) {
+      _state.setValue(StockfishState.error);
+      _instance = null;
     });
-    compute(_spawnIsolates, [_mainPort.sendPort, _stdoutPort.sendPort]).then(
-      (success) {
-        final state = success ? StockfishState.ready : StockfishState.error;
-        _state._setValue(state);
-        if (state == StockfishState.ready) {
-          completer?.complete(this);
-        }
-      },
-      onError: (error) {
-        developer.log('The init isolate encountered an error $error',
-            name: 'Stockfish');
-        _cleanUp(1);
-      },
-    );
   }
 
   static Stockfish? _instance;
@@ -82,7 +34,6 @@ class Stockfish {
     if (_instance != null) {
       throw StateError('Multiple instances are not supported, yet.');
     }
-
     _instance = Stockfish._();
     return _instance!;
   }
@@ -91,31 +42,27 @@ class Stockfish {
   ValueListenable<StockfishState> get state => _state;
 
   /// The standard output stream.
-  Stream<String> get stdout => _stdoutController.stream;
+  Stream<String> get stdout => _bindings.read;
 
   /// The standard input sink.
   set stdin(String line) {
-    final stateValue = _state.value;
+    final stateValue = state.value;
     if (stateValue != StockfishState.ready) {
       throw StateError('Stockfish is not ready ($stateValue)');
     }
-
-    final unicodePointer = '$line\n'.toNativeUtf8();
-    final pointer = unicodePointer.cast<Char>();
-    _bindings.stockfish_stdin_write(pointer);
-    calloc.free(unicodePointer);
+    _bindings.write(line);
   }
 
   /// Stops the C++ engine.
   void dispose() {
-    final stateValue = _state.value;
+    final stateValue = state.value;
     if (stateValue == StockfishState.ready) {
       stdin = 'quit';
     }
   }
 
   void _cleanUp(int exitCode) {
-    _stdoutController.close();
+    /*_stdoutController.close();
 
     _mainSubscription.cancel();
     _stdoutSubscription.cancel();
@@ -123,95 +70,6 @@ class Stockfish {
     _state._setValue(
         exitCode == 0 ? StockfishState.disposed : StockfishState.error);
 
-    _instance = null;
+    _instance = null;*/
   }
 }
-
-/// Creates a C++ engine asynchronously.
-///
-/// This method is different from the factory method [Stockfish] that
-/// it will wait for the engine to be ready before returning the instance.
-Future<Stockfish> stockfishAsync() {
-  if (Stockfish._instance != null) {
-    return Future.error(StateError('Only one instance can be used at a time'));
-  }
-
-  final completer = Completer<Stockfish>();
-  Stockfish._instance = Stockfish._(completer: completer);
-  return completer.future;
-}
-
-class _StockfishState extends ChangeNotifier
-    implements ValueListenable<StockfishState> {
-  StockfishState _value = StockfishState.starting;
-
-  @override
-  StockfishState get value => _value;
-
-  _setValue(StockfishState v) {
-    if (v == _value) return;
-    _value = v;
-    notifyListeners();
-  }
-}
-
-void _isolateMain(SendPort mainPort) {
-  final exitCode = _bindings.stockfish_main();
-  mainPort.send(exitCode);
-
-  developer.log('nativeMain returns $exitCode', name: 'Stockfish');
-}
-
-void _isolateStdout(SendPort stdoutPort) {
-  String previous = '';
-
-  while (true) {
-    final pointer = _bindings.stockfish_stdout_read();
-
-    if (pointer.address == 0) {
-      developer.log('nativeStdoutRead returns NULL', name: 'Stockfish');
-      return;
-    }
-
-    Uint8List newContentCharList;
-
-    final newContentLength = pointer.cast<Utf8>().length;
-    newContentCharList = Uint8List.view(
-        pointer.cast<Uint8>().asTypedList(newContentLength).buffer,
-        0,
-        newContentLength);
-
-    final newContent = utf8.decode(newContentCharList);
-
-    final data = previous + newContent;
-    final lines = data.split('\n');
-    previous = lines.removeLast();
-    for (final line in lines) {
-      stdoutPort.send(line);
-    }
-  }
-}
-
-Future<bool> _spawnIsolates(List<SendPort> mainAndStdout) async {
-  final initResult = _bindings.stockfish_init();
-  if (initResult != 0) {
-    developer.log('initResult=$initResult', name: 'Stockfish');
-    return false;
-  }
-
-  try {
-    await Isolate.spawn(_isolateStdout, mainAndStdout[1]);
-  } catch (error) {
-    developer.log('Failed to spawn stdout isolate: $error', name: 'Stockfish');
-    return false;
-  }
-
-  try {
-    await Isolate.spawn(_isolateMain, mainAndStdout[0]);
-  } catch (error) {
-    developer.log('Failed to spawn main isolate: $error', name: 'Stockfish');
-    return false;
-  }
-
-  return true;
-}

lib/stockfish_bindings.dart

@@ -0,0 +1,9 @@
+import 'dart:async';
+
+abstract class StockfishChessEngineAbstractBindings {
+  final stdoutController = StreamController<String>.broadcast();
+  Future<int> stockfishMain(Function active);
+  void cleanUp(int exitCode);
+  void write(String line);
+  Stream<String> get read => stdoutController.stream;
+}

lib/stockfish_c_bindings_generated.dart

@@ -5,23 +5,24 @@
 // AUTO GENERATED FILE, DO NOT EDIT.
 //
 // Generated by `package:ffigen`.
+// ignore_for_file: type=lint
 import 'dart:ffi' as ffi;
 
 /// Bindings for `src/stockfish.h`.
 ///
 /// Regenerate bindings with `dart run ffigen --config ffigen.yaml`.
 ///
-class StockfishChessEngineBindings {
+class StockfishChessEngineCBindings {
   /// Holds the symbol lookup function.
   final ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
       _lookup;
 
   /// The symbols are looked up in [dynamicLibrary].
-  StockfishChessEngineBindings(ffi.DynamicLibrary dynamicLibrary)
+  StockfishChessEngineCBindings(ffi.DynamicLibrary dynamicLibrary)
       : _lookup = dynamicLibrary.lookup;
 
   /// The symbols are looked up with [lookup].
-  StockfishChessEngineBindings.fromLookup(
+  StockfishChessEngineCBindings.fromLookup(
       ffi.Pointer<T> Function<T extends ffi.NativeType>(String symbolName)
           lookup)
       : _lookup = lookup;
@@ -56,15 +57,19 @@ class StockfishChessEngineBindings {
   late final _stockfish_stdin_write = _stockfish_stdin_writePtr
       .asFunction<int Function(ffi.Pointer<ffi.Char>)>();
 
-  ffi.Pointer<ffi.Char> stockfish_stdout_read() {
-    return _stockfish_stdout_read();
+  ffi.Pointer<ffi.Char> stockfish_stdout_read(
+    int trygetline,
+  ) {
+    return _stockfish_stdout_read(
+      trygetline,
+    );
   }
 
   late final _stockfish_stdout_readPtr =
-      _lookup<ffi.NativeFunction<ffi.Pointer<ffi.Char> Function()>>(
+      _lookup<ffi.NativeFunction<ffi.Pointer<ffi.Char> Function(ffi.Int)>>(
           'stockfish_stdout_read');
-  late final _stockfish_stdout_read =
-      _stockfish_stdout_readPtr.asFunction<ffi.Pointer<ffi.Char> Function()>();
+  late final _stockfish_stdout_read = _stockfish_stdout_readPtr
+      .asFunction<ffi.Pointer<ffi.Char> Function(int)>();
 }
 
 typedef ssize_t = __ssize_t;

lib/stockfish_native_bindings.dart

@@ -0,0 +1,148 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:ffi';
+import 'dart:io';
+import 'dart:isolate';
+import 'dart:developer' as developer;
+
+import 'package:ffi/ffi.dart';
+import 'package:flutter/foundation.dart';
+
+import 'package:flutter_stockfish_plugin/stockfish_bindings.dart';
+import 'package:flutter_stockfish_plugin/stockfish_c_bindings_generated.dart';
+
+const String _libName = 'flutter_stockfish_plugin';
+
+/// The dynamic library in which the symbols for [StockfishChessEngineCBindings] can be found.
+final DynamicLibrary _dylib = () {
+  if (Platform.isMacOS || Platform.isIOS) {
+    return DynamicLibrary.open('$_libName.framework/$_libName');
+  }
+  if (Platform.isAndroid || Platform.isLinux) {
+    return DynamicLibrary.open('lib$_libName.so');
+  }
+  if (Platform.isWindows) {
+    return DynamicLibrary.open('$_libName.dll');
+  }
+  throw UnsupportedError('Unknown platform: ${Platform.operatingSystem}');
+}();
+
+/// The bindings to the native functions in [_dylib].
+final StockfishChessEngineCBindings _bindings =
+    StockfishChessEngineCBindings(_dylib);
+
+class StockfishChessEngineBindings
+    extends StockfishChessEngineAbstractBindings {
+  final _mainPort = ReceivePort();
+  final _stdoutPort = ReceivePort();
+  late StreamSubscription _mainSubscription;
+  late StreamSubscription _stdoutSubscription;
+
+  @override
+  Future<int> stockfishMain(Function active) {
+    final completer = Completer<int>();
+    _mainSubscription = _mainPort.listen((message) {
+      cleanUp(message is int ? message : 1);
+      completer.complete(message is int ? message : 1);
+    });
+    _stdoutSubscription = _stdoutPort.listen((message) {
+      if (message is String) {
+        stdoutController.sink.add(message);
+      } else {
+        developer.log('The stdout isolate sent $message', name: 'Stockfish');
+      }
+    });
+    compute(_spawnIsolates, [_mainPort.sendPort, _stdoutPort.sendPort]).then(
+      (success) {
+        if (success) {
+          active();
+        } else {
+          completer.completeError('Unable to create Isolates');
+          cleanUp(1);
+        }
+      },
+      onError: (error) {
+        developer.log('The init isolate encountered an error $error',
+            name: 'Stockfish');
+        cleanUp(1);
+      },
+    );
+    return completer.future;
+  }
+
+  @override
+  void write(String line) {
+    final unicodePointer = '$line\n'.toNativeUtf8();
+    final pointer = unicodePointer.cast<Char>();
+    _bindings.stockfish_stdin_write(pointer);
+    calloc.free(unicodePointer);
+  }
+
+  @override
+  void cleanUp(int exitCode) {
+    stdoutController.close();
+    _mainSubscription.cancel();
+    _stdoutSubscription.cancel();
+  }
+}
+
+void _isolateMain(SendPort mainPort) {
+  final exitCode = _bindings.stockfish_main();
+  mainPort.send(exitCode);
+
+  developer.log('nativeMain returns $exitCode', name: 'Stockfish');
+}
+
+void _isolateStdout(SendPort stdoutPort) {
+  String previous = '';
+
+  while (true) {
+    final pointer = _bindings.stockfish_stdout_read(0);
+
+    if (pointer.address == 0) {
+      developer.log('nativeStdoutRead returns NULL', name: 'Stockfish');
+      return;
+    }
+
+    Uint8List newContentCharList;
+
+    final newContentLength = pointer.cast<Utf8>().length;
+    newContentCharList = Uint8List.view(
+        pointer.cast<Uint8>().asTypedList(newContentLength).buffer,
+        0,
+        newContentLength);
+
+    final newContent = utf8.decode(newContentCharList);
+
+    final data = previous + newContent;
+    final lines = data.split('\n');
+    previous = lines.removeLast();
+    for (final line in lines) {
+      stdoutPort.send(line);
+    }
+  }
+}
+
+Future<bool> _spawnIsolates(List<SendPort> mainAndStdout) async {
+  final initResult = _bindings.stockfish_init();
+  if (initResult != 0) {
+    developer.log('initResult=$initResult', name: 'Stockfish');
+    return false;
+  }
+
+  try {
+    await Isolate.spawn(_isolateStdout, mainAndStdout[1]);
+  } catch (error) {
+    developer.log('Failed to spawn stdout isolate: $error', name: 'Stockfish');
+    return false;
+  }
+
+  try {
+    await Isolate.spawn(_isolateMain, mainAndStdout[0]);
+  } catch (error) {
+    developer.log('Failed to spawn main isolate: $error', name: 'Stockfish');
+    return false;
+  }
+
+  return true;
+}

lib/stockfish_state.dart

@@ -1,4 +1,20 @@
-// Taken from https://github.com/ArjanAswal/Stockfish/blob/master/lib/src/stockfish_state.dart
+import 'package:flutter/foundation.dart';
+
+class StockfishStateClass extends ChangeNotifier
+    implements ValueListenable<StockfishState> {
+  StockfishState _value = StockfishState.starting;
+
+  @override
+  StockfishState get value => _value;
+
+  setValue(StockfishState v) {
+    if (v == _value) return;
+    _value = v;
+    notifyListeners();
+  }
+}
+
+// The following is taken from https://github.com/ArjanAswal/Stockfish/blob/master/lib/src/stockfish_state.dart
 
 /// C++ engine state.
 enum StockfishState {

lib/stockfish_web_bindings.dart

@@ -0,0 +1,25 @@
+import 'dart:async';
+
+import 'package:flutter_stockfish_plugin/stockfish_bindings.dart';
+
+class StockfishChessEngineBindings
+    extends StockfishChessEngineAbstractBindings {
+  @override
+  void cleanUp(int exitCode) {
+    // TODO: implement cleanUp
+  }
+
+  @override
+  Future<int> stockfishMain(Function active) {
+    // TODO: implement stockfishMain
+    final completer = Completer<int>();
+    //completer.complete(0);
+    active();
+    return completer.future;
+  }
+
+  @override
+  void write(String line) {
+    // TODO: implement write
+  }
+}

src/CMakeLists.txt

@@ -10,7 +10,7 @@ set(CMAKE_CXX_STANDARD 17)
 if(MSVC)
   set(COMMON_FLAGS "/std:c++17 /LTCG")
 
-  set(SIMD_FLAGS "/arch:AVX2 /arch:SSE /DUSE_POPCNT /DUSE_SSE41 /DUSE_SSSE3 /DUSE_SSE2")
+  set(SIMD_FLAGS "/arch:AVX2 /DUSE_POPCNT /arch:SSE /DUSE_SSE2 /DUSE_SSSE3 /DUSE_SSE41")
 
   if (CMAKE_SIZEOF_VOID_P EQUAL 8)
     message(STATUS "Adding x86_64 specific flags")
@@ -25,9 +25,9 @@ if(MSVC)
     set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Ox /DNDEBUG")
 
 else()
-  set(COMMON_FLAGS "-Wall -Wcast-qual -fno-exceptions -std=c++17 -pedantic -Wextra -Wshadow -Wmissing-declarations -flto -DUSE_PTHREADS") 
+  set(COMMON_FLAGS "-Wall -Wcast-qual -Wno-main -fno-exceptions -std=c++17 -pedantic -Wextra -Wshadow -Wmissing-declarations -flto -DUSE_PTHREADS") 
 
-  set(SIMD_FLAGS "-msse -msse3 -mpopcnt -DUSE_POPCNT -DUSE_SSE41 -msse4.1 -DUSE_SSSE3 -mssse3 -DUSE_SSE2 -msse2")
+  set(SIMD_FLAGS "-mpopcnt -DUSE_POPCNT -msse -DUSE_SSE2 -msse2 -msse3 -DUSE_SSSE3 -mssse3 -DUSE_SSE41 -msse4.1 -DUSE_SSE42 -msse4.2")
 
   if (CMAKE_SYSTEM_PROCESSOR MATCHES "x86_64")
     message(STATUS "Adding x86_64 specific flags")

src/stockfish.cpp

@@ -15,9 +15,11 @@
 #include "fixes.h"
 #include "stockfish.h"
 
-const char *QUITOK = "quitok\n";
+const char* QUITOK = "quitok\n";
 
-int main(int, char **);
+void runMain() {}
+
+int main(int, char**);
 
 int stockfish_init() {
     fakein.open();
@@ -27,8 +29,11 @@ int stockfish_init() {
 
 int stockfish_main() {
     int argc = 1;
-    char *argv[] = {(char *)""};
+    char* empty = (char*)malloc(0);
+    *empty = 0;
+    char* argv[] = {empty};
     int exitCode = main(argc, argv);
+    free(empty);
 
     fakeout << QUITOK << "\n";
 
@@ -44,7 +49,7 @@ int stockfish_main() {
     return exitCode;
 }
 
-ssize_t stockfish_stdin_write(char *data) {
+ssize_t stockfish_stdin_write(char* data) {
     std::string val(data);
     fakein << val << fakeendl;
     return val.length();
@@ -52,9 +57,15 @@ ssize_t stockfish_stdin_write(char *data) {
 
 std::string data;
 
-const char *stockfish_stdout_read() {
-    if (getline(fakeout, data)) {
-        return data.c_str();
+const char* stockfish_stdout_read(int trygetline) {
+    if (trygetline) {
+        if (fakeout.try_get_line(data)) {
+            return data.c_str();
+        }
+    } else {
+        if (getline(fakeout, data)) {
+            return data.c_str();
+        }
     }
     return nullptr;
 }

src/stockfish.h

@@ -20,29 +20,34 @@
 #ifdef _WIN32
 #define FFI_PLUGIN_EXPORT __declspec(dllexport)
 #else
-#define FFI_PLUGIN_EXPORT __attribute__((visibility("default"))) __attribute__((used))
+#define FFI_PLUGIN_EXPORT \
+    __attribute__((visibility("default"))) __attribute__((used))
 #endif
 
 // Initialisation of Stockfish.
 #ifndef _ffigen
 extern "C"
 #endif
-FFI_PLUGIN_EXPORT int stockfish_init();
+    FFI_PLUGIN_EXPORT int
+    stockfish_init();
 
 // Stockfish main loop.
 #ifndef _ffigen
 extern "C"
 #endif
-FFI_PLUGIN_EXPORT int stockfish_main();
+    FFI_PLUGIN_EXPORT int
+    stockfish_main();
 
 // Writing to Stockfish STDIN.
 #ifndef _ffigen
 extern "C"
 #endif
-FFI_PLUGIN_EXPORT ssize_t stockfish_stdin_write(char *data);
+    FFI_PLUGIN_EXPORT ssize_t
+    stockfish_stdin_write(char* data);
 
 // Reading Stockfish STDOUT
 #ifndef _ffigen
 extern "C"
 #endif
-FFI_PLUGIN_EXPORT const char * stockfish_stdout_read();
+    FFI_PLUGIN_EXPORT const char*
+    stockfish_stdout_read(int trygetline);

src/stream_fix.cpp

@@ -2,7 +2,8 @@
 
 bool FakeStream::try_get_line(std::string& val) {
     std::unique_lock<std::mutex> lock(mutex_guard);
-    if (string_queue.empty() || closed) return false;
+    if (string_queue.empty() || closed)
+        return false;
     val = string_queue.front();
     string_queue.pop();
     return true;
@@ -20,18 +21,27 @@ void FakeStream::close() {
     while (!string_queue.empty()) {
         string_queue.pop();
     }
-    mutex_signal.notify_one();
+    mutex_signal.notify_all();
+}
+bool FakeStream::is_closed() {
+    return closed;
 }
-bool FakeStream::is_closed() { return closed; }
 
-std::streambuf* FakeStream::rdbuf() { return nullptr; }
+std::streambuf* FakeStream::rdbuf() {
+    return nullptr;
+}
 
-std::streambuf* FakeStream::rdbuf(std::streambuf* buf) { return nullptr; }
+std::streambuf* FakeStream::rdbuf(std::streambuf* buf) {
+    (void)buf;
+    return nullptr;
+}
 
 bool std::getline(FakeStream& is, std::string& str) {
-    if (is.is_closed()) return false;
+    if (is.is_closed())
+        return false;
     is >> str;
-    if (is.is_closed()) return false;
+    if (is.is_closed())
+        return false;
     return true;
 }
 

src/stream_fix.h

@@ -6,18 +6,24 @@
 #include <queue>
 #include <sstream>
 
+#ifdef __EMSCRIPTEN__
+#include <emscripten.h>
+#include <emscripten/threading.h>
+#endif
+
 template <typename T>
 inline std::string stringify(const T& input) {
     std::ostringstream output;  // from   www  .ja va  2s  . com
     output << input;
-    return output.str();
+    return std::string(output.str());
 }
 
 class FakeStream {
    public:
     template <typename T>
     FakeStream& operator<<(const T& val) {
-        if (closed) return *this;
+        if (closed)
+            return *this;
         std::lock_guard<std::mutex> lock(mutex_guard);
         string_queue.push(stringify(val));
         mutex_signal.notify_one();
@@ -25,29 +31,46 @@ class FakeStream {
     };
     template <typename T>
     FakeStream& operator>>(T& val) {
-        if (closed) return *this;
+        if (closed)
+            return *this;
         std::unique_lock<std::mutex> lock(mutex_guard);
+#ifdef __EMSCRIPTEN__
+        if (emscripten_is_main_runtime_thread()) {
+            lock.unlock();
+            while (true) {
+                lock = std::unique_lock<std::mutex>(mutex_guard);
+                if (!string_queue.empty() || closed)
+                    break;
+                lock.unlock();
+                emscripten_sleep(10);
+            }
+        } else {
+            mutex_signal.wait(
+                lock, [this] { return !string_queue.empty() || closed; });
+        }
+#else
         mutex_signal.wait(lock,
                           [this] { return !string_queue.empty() || closed; });
-        if (closed) return *this;
+#endif
+        if (closed)
+            return *this;
         val = string_queue.front();
         string_queue.pop();
         return *this;
     };
 
-    bool try_get_line(std::string& val);
+    bool try_get_line(std::string&);
 
     void open();
     void close();
     bool is_closed();
 
     std::streambuf* rdbuf();
-    std::streambuf* rdbuf(std::streambuf* __sb);
+    std::streambuf* rdbuf(std::streambuf*);
 
    private:
     bool closed = false;
     std::queue<std::string> string_queue;
-    //std::string line;
     std::mutex mutex_guard;
     std::condition_variable mutex_signal;
 };
@@ -56,10 +79,6 @@ namespace std {
 bool getline(FakeStream& is, std::string& str);
 }  // namespace std
 
-// #define endl fakeendl
-// #define cout fakeout
-// #define cin fakein
-
 extern FakeStream fakeout;
 extern FakeStream fakein;
 extern std::string fakeendl;