🐛 Fix crash on dispose while running 'RunAsync'

Packages/com.github.asus4.tflite.common/Runtime/BaseVisionTask.cs

@@ -24,6 +24,8 @@ public abstract class BaseVisionTask : IDisposable
  protected int channels;
  protected TextureToNativeTensor textureToTensor;
 
+ private readonly SemaphoreSlim semaphore = new SemaphoreSlim(1, 1);
+ private bool isDisposed = false;
 
  public AspectMode AspectMode { get; set; } = AspectMode.None;
 
@@ -57,8 +59,20 @@ public virtual void Load(byte[] model, InterpreterOptions options)
 
  public virtual void Dispose()
  {
- interpreter?.Dispose();
- textureToTensor?.Dispose();
+ semaphore.Wait();
+ try
+ {
+ if (!isDisposed)
+ {
+ interpreter?.Dispose();
+ textureToTensor?.Dispose();
+ isDisposed = true;
+ }
+ }
+ finally
+ {
+ semaphore.Release();
+ }
  }
 
  /// <summary>
@@ -67,6 +81,11 @@ public virtual void Dispose()
  /// <param name="texture">A texture for model input</param>
  public virtual void Run(Texture texture)
  {
+ if (isDisposed)
+ {
+ throw new ObjectDisposedException(nameof(BaseVisionTask));
+ }
+
  // Pre process
  preprocessPerfMarker.Begin();
  PreProcess(texture);
@@ -100,24 +119,37 @@ protected virtual void PreProcess(Texture texture)
  protected abstract void PostProcess();
 
  // Only available when UniTask is installed
-#if TFLITE_UNITASK_ENABLED
+#if TFLITE_UNITASK_ENABLED || true
  public virtual async UniTask RunAsync(Texture texture, CancellationToken cancellationToken)
  {
- // Pre process
- preprocessPerfMarker.Begin();
- await PreProcessAsync(texture, cancellationToken);
- preprocessPerfMarker.End();
-
- // Run inference in BG thread
- await UniTask.SwitchToThreadPool();
- runPerfMarker.Begin();
- interpreter.Invoke();
- runPerfMarker.End();
+ if (isDisposed)
+ {
+ throw new ObjectDisposedException(nameof(BaseVisionTask));
+ }
 
- // Post process
- postprocessPerfMarker.Begin();
- await PostProcessAsync(cancellationToken);
- postprocessPerfMarker.End();
+ await semaphore.WaitAsync(cancellationToken);
+ try
+ {
+ // Pre process
+ preprocessPerfMarker.Begin();
+ await PreProcessAsync(texture, cancellationToken);
+ preprocessPerfMarker.End();
+
+ // Run inference in BG thread
+ await UniTask.SwitchToThreadPool();
+ runPerfMarker.Begin();
+ interpreter.Invoke();
+ runPerfMarker.End();
+
+ // Post process
+ postprocessPerfMarker.Begin();
+ await PostProcessAsync(cancellationToken);
+ postprocessPerfMarker.End();
+ }
+ finally
+ {
+ semaphore.Release();
+ }
 
  // Back to main thread
  await UniTask.SwitchToMainThread();