fix: check Packet types at compile-time more properly (#509)

* fix!(plugin): default constructors of Packet classes cause memory leak

* test Packet#At

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Core/MpResourceHandle.cs

@@ -10,7 +10,19 @@ namespace Mediapipe
 {
   public abstract class MpResourceHandle : DisposableObject, IMpResourceHandle
   {
-    protected IntPtr ptr;
+    private IntPtr _ptr = IntPtr.Zero;
+    protected IntPtr ptr
+    {
+      get => _ptr;
+      set
+      {
+        if (value != IntPtr.Zero && OwnsResource())
+        {
+          throw new InvalidOperationException($"This object owns another resource");
+        }
+        _ptr = value;
+      }
+    }
 
     protected MpResourceHandle(bool isOwner = true) : this(IntPtr.Zero, isOwner) { }
 
@@ -40,7 +52,7 @@ public void ReleaseMpResource()
 
     public bool OwnsResource()
     {
-      return isOwner && ptr != IntPtr.Zero;
+      return isOwner && IsResourcePresent();
     }
     #endregion
 
@@ -80,5 +92,10 @@ protected string MarshalStringFromNative(StringOutFunc f)
 
       return str;
     }
+
+    protected bool IsResourcePresent()
+    {
+      return ptr != IntPtr.Zero;
+    }
   }
 }

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/CalculatorGraph.cs

@@ -79,14 +79,14 @@ public Status ObserveOutputStream(string streamName, NativePacketCallback native
       return new Status(statusPtr);
     }
 
-    public Status ObserveOutputStream<TPacket, TValue>(string streamName, PacketCallback<TPacket, TValue> packetCallback, bool observeTimestampBounds, out GCHandle callbackHandle) where TPacket : Packet<TValue>
+    public Status ObserveOutputStream<TPacket, TValue>(string streamName, PacketCallback<TPacket, TValue> packetCallback, bool observeTimestampBounds, out GCHandle callbackHandle) where TPacket : Packet<TValue>, new()
     {
       NativePacketCallback nativePacketCallback = (IntPtr _, IntPtr packetPtr) =>
       {
         Status status = null;
         try
         {
-          var packet = (TPacket)Activator.CreateInstance(typeof(TPacket), packetPtr, false);
+          var packet = Packet<TValue>.Create<TPacket>(packetPtr, false);
           status = packetCallback(packet);
         }
         catch (Exception e)
@@ -100,7 +100,7 @@ public Status ObserveOutputStream(string streamName, NativePacketCallback native
       return ObserveOutputStream(streamName, nativePacketCallback, observeTimestampBounds);
     }
 
-    public Status ObserveOutputStream<TPacket, TValue>(string streamName, PacketCallback<TPacket, TValue> packetCallback, out GCHandle callbackHandle) where TPacket : Packet<TValue>
+    public Status ObserveOutputStream<TPacket, TValue>(string streamName, PacketCallback<TPacket, TValue> packetCallback, out GCHandle callbackHandle) where TPacket : Packet<TValue>, new()
     {
       return ObserveOutputStream(streamName, packetCallback, false, out callbackHandle);
     }

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/Anchor3dVectorPacket.cs

@@ -11,7 +11,11 @@ namespace Mediapipe
 {
   public class Anchor3dVectorPacket : Packet<List<Anchor3d>>
   {
-    public Anchor3dVectorPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="Anchor3dVectorPacket" /> instance.
+    /// </summary>
+    public Anchor3dVectorPacket() : base(true) { }
+
     public Anchor3dVectorPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
     public Anchor3dVectorPacket(Anchor3d[] value) : base()
@@ -27,6 +31,11 @@ public Anchor3dVectorPacket(Anchor3d[] value, Timestamp timestamp) : base()
       this.ptr = ptr;
     }
 
+    public Anchor3dVectorPacket At(Timestamp timestamp)
+    {
+      return At<Anchor3dVectorPacket>(timestamp);
+    }
+
     public override List<Anchor3d> Get()
     {
       UnsafeNativeMethods.mp_Packet__GetAnchor3dVector(mpPtr, out var anchorVector).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/BoolPacket.cs

@@ -10,7 +10,10 @@ namespace Mediapipe
 {
   public class BoolPacket : Packet<bool>
   {
-    public BoolPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="BoolPacket" /> instance.
+    /// </summary>
+    public BoolPacket() : base(true) { }
 
     public BoolPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
@@ -27,6 +30,11 @@ public BoolPacket(bool value, Timestamp timestamp) : base()
       this.ptr = ptr;
     }
 
+    public BoolPacket At(Timestamp timestamp)
+    {
+      return At<BoolPacket>(timestamp);
+    }
+
     public override bool Get()
     {
       UnsafeNativeMethods.mp_Packet__GetBool(mpPtr, out var value).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/ClassificationListPacket.cs

@@ -10,9 +10,18 @@ namespace Mediapipe
 {
   public class ClassificationListPacket : Packet<ClassificationList>
   {
-    public ClassificationListPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="ClassificationListPacket" /> instance.
+    /// </summary>
+    public ClassificationListPacket() : base(true) { }
+
     public ClassificationListPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public ClassificationListPacket At(Timestamp timestamp)
+    {
+      return At<ClassificationListPacket>(timestamp);
+    }
+
     public override ClassificationList Get()
     {
       UnsafeNativeMethods.mp_Packet__GetClassificationList(mpPtr, out var serializedProto).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/ClassificationListVectorPacket.cs

@@ -11,9 +11,18 @@ namespace Mediapipe
 {
   public class ClassificationListVectorPacket : Packet<List<ClassificationList>>
   {
-    public ClassificationListVectorPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="ClassificationListVectorPacket" /> instance.
+    /// </summary>
+    public ClassificationListVectorPacket() : base(true) { }
+
     public ClassificationListVectorPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public ClassificationListVectorPacket At(Timestamp timestamp)
+    {
+      return At<ClassificationListVectorPacket>(timestamp);
+    }
+
     public override List<ClassificationList> Get()
     {
       UnsafeNativeMethods.mp_Packet__GetClassificationListVector(mpPtr, out var serializedProtoVector).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/DetectionPacket.cs

@@ -10,9 +10,18 @@ namespace Mediapipe
 {
   public class DetectionPacket : Packet<Detection>
   {
-    public DetectionPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="DetectionPacket" /> instance.
+    /// </summary>
+    public DetectionPacket() : base(true) { }
+
     public DetectionPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public DetectionPacket At(Timestamp timestamp)
+    {
+      return At<DetectionPacket>(timestamp);
+    }
+
     public override Detection Get()
     {
       UnsafeNativeMethods.mp_Packet__GetDetection(mpPtr, out var serializedProto).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/DetectionVectorPacket.cs

@@ -11,9 +11,18 @@ namespace Mediapipe
 {
   public class DetectionVectorPacket : Packet<List<Detection>>
   {
-    public DetectionVectorPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="DetectionVectorPacket" /> instance.
+    /// </summary>
+    public DetectionVectorPacket() : base(true) { }
+
     public DetectionVectorPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public DetectionVectorPacket At(Timestamp timestamp)
+    {
+      return At<DetectionVectorPacket>(timestamp);
+    }
+
     public override List<Detection> Get()
     {
       UnsafeNativeMethods.mp_Packet__GetDetectionVector(mpPtr, out var serializedProtoVector).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/FaceGeometryPacket.cs

@@ -10,9 +10,18 @@ namespace Mediapipe
 {
   public class FaceGeometryPacket : Packet<FaceGeometry.FaceGeometry>
   {
-    public FaceGeometryPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="FaceGeometryPacket" /> instance.
+    /// </summary>
+    public FaceGeometryPacket() : base(true) { }
+
     public FaceGeometryPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public FaceGeometryPacket At(Timestamp timestamp)
+    {
+      return At<FaceGeometryPacket>(timestamp);
+    }
+
     public override FaceGeometry.FaceGeometry Get()
     {
       UnsafeNativeMethods.mp_Packet__GetFaceGeometry(mpPtr, out var serializedProto).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/FaceGeometryVectorPacket.cs

@@ -11,9 +11,18 @@ namespace Mediapipe
 {
   public class FaceGeometryVectorPacket : Packet<List<FaceGeometry.FaceGeometry>>
   {
-    public FaceGeometryVectorPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="FaceGeometryVectorPacket" /> instance.
+    /// </summary>
+    public FaceGeometryVectorPacket() : base(true) { }
+
     public FaceGeometryVectorPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public FaceGeometryVectorPacket At(Timestamp timestamp)
+    {
+      return At<FaceGeometryVectorPacket>(timestamp);
+    }
+
     public override List<FaceGeometry.FaceGeometry> Get()
     {
       UnsafeNativeMethods.mp_Packet__GetFaceGeometryVector(mpPtr, out var serializedProtoVector).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/FloatArrayPacket.cs

@@ -26,7 +26,10 @@ public int length
       }
     }
 
-    public FloatArrayPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="FloatArrayPacket" /> instance.
+    /// </summary>
+    public FloatArrayPacket() : base(true) { }
 
     public FloatArrayPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
@@ -45,6 +48,11 @@ public FloatArrayPacket(float[] value, Timestamp timestamp) : base()
       length = value.Length;
     }
 
+    public FloatArrayPacket At(Timestamp timestamp)
+    {
+      return At<FloatArrayPacket>(timestamp);
+    }
+
     public override float[] Get()
     {
       if (length < 0)

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/FloatPacket.cs

@@ -10,7 +10,10 @@ namespace Mediapipe
 {
   public class FloatPacket : Packet<float>
   {
-    public FloatPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="FloatPacket" /> instance.
+    /// </summary>
+    public FloatPacket() : base(true) { }
 
     public FloatPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
@@ -27,6 +30,11 @@ public FloatPacket(float value, Timestamp timestamp) : base()
       this.ptr = ptr;
     }
 
+    public FloatPacket At(Timestamp timestamp)
+    {
+      return At<FloatPacket>(timestamp);
+    }
+
     public override float Get()
     {
       UnsafeNativeMethods.mp_Packet__GetFloat(mpPtr, out var value).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/FrameAnnotationPacket.cs

@@ -10,9 +10,18 @@ namespace Mediapipe
 {
   public class FrameAnnotationPacket : Packet<FrameAnnotation>
   {
-    public FrameAnnotationPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="FrameAnnotationPacket" /> instance.
+    /// </summary>
+    public FrameAnnotationPacket() : base(true) { }
+
     public FrameAnnotationPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public FrameAnnotationPacket At(Timestamp timestamp)
+    {
+      return At<FrameAnnotationPacket>(timestamp);
+    }
+
     public override FrameAnnotation Get()
     {
       UnsafeNativeMethods.mp_Packet__GetFrameAnnotation(mpPtr, out var serializedProto).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/GpuBufferPacket.cs

@@ -10,7 +10,11 @@ namespace Mediapipe
 {
   public class GpuBufferPacket : Packet<GpuBuffer>
   {
-    public GpuBufferPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="GpuBufferPacket" /> instance.
+    /// </summary>
+    public GpuBufferPacket() : base(true) { }
+
     public GpuBufferPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
     public GpuBufferPacket(GpuBuffer gpuBuffer) : base()
@@ -30,6 +34,11 @@ public GpuBufferPacket(GpuBuffer gpuBuffer, Timestamp timestamp)
       this.ptr = ptr;
     }
 
+    public GpuBufferPacket At(Timestamp timestamp)
+    {
+      return At<GpuBufferPacket>(timestamp);
+    }
+
     public override GpuBuffer Get()
     {
       UnsafeNativeMethods.mp_Packet__GetGpuBuffer(mpPtr, out var gpuBufferPtr).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/ImageFramePacket.cs

@@ -10,7 +10,10 @@ namespace Mediapipe
 {
   public class ImageFramePacket : Packet<ImageFrame>
   {
-    public ImageFramePacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="ImageFramePacket" /> instance.
+    /// </summary>
+    public ImageFramePacket() : base(true) { }
 
     public ImageFramePacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
@@ -31,6 +34,11 @@ public ImageFramePacket(ImageFrame imageFrame, Timestamp timestamp) : base()
       this.ptr = ptr;
     }
 
+    public ImageFramePacket At(Timestamp timestamp)
+    {
+      return At<ImageFramePacket>(timestamp);
+    }
+
     public override ImageFrame Get()
     {
       UnsafeNativeMethods.mp_Packet__GetImageFrame(mpPtr, out var imageFramePtr).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/IntPacket.cs

@@ -10,7 +10,10 @@ namespace Mediapipe
 {
   public class IntPacket : Packet<int>
   {
-    public IntPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="IntPacket" /> instance.
+    /// </summary>
+    public IntPacket() : base(true) { }
 
     public IntPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
@@ -27,6 +30,11 @@ public IntPacket(int value, Timestamp timestamp) : base()
       this.ptr = ptr;
     }
 
+    public IntPacket At(Timestamp timestamp)
+    {
+      return At<IntPacket>(timestamp);
+    }
+
     public override int Get()
     {
       UnsafeNativeMethods.mp_Packet__GetInt(mpPtr, out var value).Assert();

Packages/com.github.homuler.mediapipe/Runtime/Scripts/Framework/Packet/LandmarkListPacket.cs

@@ -10,9 +10,18 @@ namespace Mediapipe
 {
   public class LandmarkListPacket : Packet<LandmarkList>
   {
-    public LandmarkListPacket() : base() { }
+    /// <summary>
+    ///   Creates an empty <see cref="LandmarkListPacket" /> instance.
+    /// </summary>
+    public LandmarkListPacket() : base(true) { }
+
     public LandmarkListPacket(IntPtr ptr, bool isOwner = true) : base(ptr, isOwner) { }
 
+    public LandmarkListPacket At(Timestamp timestamp)
+    {
+      return At<LandmarkListPacket>(timestamp);
+    }
+
     public override LandmarkList Get()
     {
       UnsafeNativeMethods.mp_Packet__GetLandmarkList(mpPtr, out var serializedProto).Assert();