fix: stop() takes too much time

example/pubspec.lock

@@ -132,7 +132,7 @@ packages:
       path: ".."
       relative: true
     source: path
-    version: "3.3.3"
+    version: "3.3.6"
   flutter_test:
     dependency: "direct dev"
     description: flutter

example/tests/tests.dart

@@ -547,23 +547,33 @@ Future<StringBuffer> testStopFutures() async {
 
   /// Load sample
   final currentSound =
-      await SoLoud.instance.loadAsset('assets/audio/tic-1.wav');
+      await SoLoud.instance.loadAsset('assets/audio/explosion.mp3');
 
-  final random = Random(42);
-  for (var i = 0; i < 50; i++) {
-    final handle = await SoLoud.instance.play(currentSound);
-    output.writeln('$handle started');
-    await Future<void>.delayed(Duration(milliseconds: random.nextInt(5)));
-    unawaited(
-      SoLoud.instance
-          .stop(handle)
-          .then((_) => output.writeln('$handle stopped')),
-    );
-  }
+  /// Fast call to `stop` after `play`
+  var handle = await SoLoud.instance.play(currentSound);
+  output
+    ..writeln('fast play/stop')
+    ..writeln('$handle started');
+  unawaited(
+    SoLoud.instance.stop(handle).then((_) => output.writeln('$handle stopped')),
+  );
 
-  /// Wait a bit so that we can hear a sound to verify it's working as intended.
   await delay(500);
 
+  /// Schedule a stop and call `stop` after the scheduled time
+  handle = await SoLoud.instance.play(currentSound);
+  output
+    ..writeln('\nscheduleStop')
+    ..writeln('$handle started');
+  SoLoud.instance.scheduleStop(handle, const Duration(milliseconds: 500));
+  await delay(1000);
+  unawaited(
+    SoLoud.instance.stop(handle).then((_) => output.writeln('$handle stopped')),
+  );
+
+  /// Wait a bit.
+  await delay(1000);
+
   deinit();
 
   if (severeLogs.isNotEmpty) {

lib/src/soloud.dart

@@ -1329,7 +1329,16 @@ interface class SoLoud {
     final completer = Completer<void>();
     voiceEndedCompleters[handle] = completer;
 
-    _controller.soLoudFFI.stop(handle);
+    // In the case this handle has been ended or stopped by [scheduleStop],
+    // we should check if it is still valid.
+    if (!getIsValidVoiceHandle(handle)) {
+      _log.finest(
+          () => 'The handle $handle has already been removed by another '
+              'event like scheduleStop or ended sound.');
+      completer.complete();
+    } else {
+      _controller.soLoudFFI.stop(handle);
+    }
 
     return completer.future
         .timeout(const Duration(milliseconds: 300))

src/bindings.cpp

@@ -108,8 +108,23 @@ extern "C"
     /// and comes from the audio thread (so on the web, from a different web worker).
     FFI_PLUGIN_EXPORT void voiceEndedCallback(unsigned int *handle)
     {
+        bool isHandleFound;
         if (player != nullptr)
-            player->removeHandle(*handle);
+        {
+            isHandleFound = player->findByHandle(*handle) != nullptr;
+            if (isHandleFound)
+                player->removeHandle(*handle);
+            else
+                // If the handle is not found, for sure it is already
+                // removed by a previous call to `voiceEndedCallback`.
+                // For example triggering a `stop` in a `Future` after the sound is ended or
+                // vice versa.
+                return;
+        }
+
+        // Here the internal flutter_soloud handle, doesn't exist anymore, whether this
+        // callback is called directly from `stop`, or whether it is called from an
+        // event in `Soloud::stopVoice_internal (unsigned int aVoice)`.
 
 #ifdef __EMSCRIPTEN__
         // Calling JavaScript from C/C++
@@ -121,7 +136,12 @@ extern "C"
         // The `dartVoiceEndedCallback` is not set on Web.
         if (dartVoiceEndedCallback == nullptr)
             return;
-        // [n] pointer must be deleted on Dart.
+        // So, if the handle was already found before (henche the handle is not found), the
+        // callback to Dart has been already called. If this is the fist time this handle 
+        // is found, the callback to Dart must be called.
+        if (!isHandleFound)
+            return;
+        // [n] pointer must be deleted in Dart.
         unsigned int *n = (unsigned int *)malloc(sizeof(unsigned int *));
         *n = *handle;
         dartVoiceEndedCallback(n);
@@ -770,10 +790,10 @@ extern "C"
     /// [handle]
     FFI_PLUGIN_EXPORT void stop(unsigned int handle)
     {
-        if (player.get() == nullptr || !player.get()->isInited() ||
-            !player.get()->isValidHandle(handle))
+        if (player.get() == nullptr || !player.get()->isInited())
             return;
         player.get()->stop(handle);
+        voiceEndedCallback(&handle);
     }
 
     /// Stop all handles of the already loaded sound identified by [hash] and dispose it

src/player.cpp

@@ -634,7 +634,6 @@ PlayerErrors Player::play(
 
 void Player::stop(unsigned int handle)
 {
-    removeHandle(handle);
     soloud.stop(handle);
 }