refactor: marshal delegate directly

Assets/MediaPipe/SDK/Scripts/External/Protobuf.cs

@@ -8,7 +8,7 @@
 namespace Mediapipe {
   class Protobuf {
     static Protobuf() {
-      UnsafeNativeMethods.google_protobuf__SetLogHandler__PF(Marshal.GetFunctionPointerForDelegate(protobufLogHandler)).Assert();
+      UnsafeNativeMethods.google_protobuf__SetLogHandler__PF(protobufLogHandler).Assert();
     }
 
     /// <exception cref="MediaPipeException">Thrown when an error occured in unmanaged code</exception>
@@ -47,8 +47,7 @@ public static List<T> DeserializeProtoVector<T>(IntPtr ptr, pb::MessageParser<T>
       return protos;
     }
 
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-    private delegate void ProtobufLogHandler(int level, string filename, int line, string message);
+    public delegate void ProtobufLogHandler(int level, string filename, int line, string message);
     private static readonly ProtobufLogHandler protobufLogHandler = LogProtobufMessage;
 
     private static void LogProtobufMessage(int level, string filename, int line, string message) {

Assets/MediaPipe/SDK/Scripts/Framework/Formats/ImageFrame.cs

@@ -9,11 +9,9 @@ public class ImageFrame : MpResourceHandle {
     public static readonly uint kDefaultAlignmentBoundary = 16;
     public static readonly uint kGlDefaultAlignmentBoundary = 4;
 
+    public delegate void Deleter(IntPtr ptr);
     private GCHandle deleterHandle;
 
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-    private delegate void Deleter(IntPtr ptr);
-
     public ImageFrame() : base() {
       UnsafeNativeMethods.mp_ImageFrame__(out var ptr).Assert();
       this.ptr = ptr;
@@ -36,7 +34,7 @@ public ImageFrame(ImageFormat.Format format, int width, int height, int widthSte
         UnsafeNativeMethods.mp_ImageFrame__ui_i_i_i_Pui8_PF(
           format, width, height, widthStep,
           (IntPtr)NativeArrayUnsafeUtility.GetUnsafeReadOnlyPtr(pixelData),
-          Marshal.GetFunctionPointerForDelegate(deleter),
+          deleter,
           out var ptr
         ).Assert();
         this.ptr = ptr;

Assets/MediaPipe/SDK/Scripts/Gpu/GlCalculatorHelper.cs

@@ -4,8 +4,7 @@
 namespace Mediapipe {
 
   public class GlCalculatorHelper : MpResourceHandle {
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-    private delegate IntPtr MpGlStatusFunction();
+    public delegate IntPtr NativeGlStatusFunction();
     public delegate Status GlStatusFunction();
 
     public GlCalculatorHelper() : base() {
@@ -25,19 +24,24 @@ public void InitializeForTest(GpuResources gpuResources) {
     }
 
     public Status RunInGlContext(GlStatusFunction glStatusFunc) {
-      MpGlStatusFunction mpGlStatusFunc = () => {
+      Status status = null;
+
+      NativeGlStatusFunction nativeGlStatusFunc = () => {
         try {
-          return glStatusFunc().mpPtr;
+          status = glStatusFunc();
         } catch (Exception e) {
-          return Status.FailedPrecondition(e.ToString()).mpPtr;
+          status = Status.FailedPrecondition(e.ToString());
         }
+        return status.mpPtr;
       };
-      GCHandle mpGlStatusFuncHandle = GCHandle.Alloc(mpGlStatusFunc);
-      UnsafeNativeMethods.mp_GlCalculatorHelper__RunInGlContext__PF(
-          mpPtr, Marshal.GetFunctionPointerForDelegate(mpGlStatusFunc), out var statusPtr).Assert();
-      mpGlStatusFuncHandle.Free();
 
+      GCHandle nativeGlStatusFuncHandle = GCHandle.Alloc(nativeGlStatusFunc, GCHandleType.Pinned);
+      UnsafeNativeMethods.mp_GlCalculatorHelper__RunInGlContext__PF(mpPtr, nativeGlStatusFunc, out var statusPtr).Assert();
       GC.KeepAlive(this);
+      nativeGlStatusFuncHandle.Free();
+
+      if (status != null) { status.Dispose(); }
+
       return new Status(statusPtr);
     }
 

Assets/MediaPipe/SDK/Scripts/Gpu/GlTextureBuffer.cs

@@ -5,7 +5,6 @@ namespace Mediapipe {
   public class GlTextureBuffer : MpResourceHandle {
     private SharedPtrHandle sharedPtrHandle;
 
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
     public delegate void DeletionCallback(IntPtr glSyncToken);
     private GCHandle deletionCallbackHandle;
 
@@ -20,7 +19,7 @@ public GlTextureBuffer(UInt32 target, UInt32 name, int width, int height,
       deletionCallbackHandle = GCHandle.Alloc(callback, GCHandleType.Pinned);
       var sharedContextPtr = glContext == null ? IntPtr.Zero : glContext.sharedPtr;
       UnsafeNativeMethods.mp_SharedGlTextureBuffer__ui_ui_i_i_ui_PF_PSgc(
-          target, name, width, height, format, Marshal.GetFunctionPointerForDelegate(callback), sharedContextPtr, out var ptr).Assert();
+          target, name, width, height, format, callback, sharedContextPtr, out var ptr).Assert();
 
       this.ptr = ptr;
     }

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/External/Glog_Unsafe.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Runtime.InteropServices;
 
 namespace Mediapipe {

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/External/Protobuf_Unsafe.cs

@@ -4,7 +4,8 @@
 namespace Mediapipe {
   internal static partial class UnsafeNativeMethods {
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
-    public static extern MpReturnCode google_protobuf__SetLogHandler__PF([MarshalAs(UnmanagedType.FunctionPtr)]IntPtr logHandler);
+    public static extern MpReturnCode google_protobuf__SetLogHandler__PF(
+        [MarshalAs(UnmanagedType.FunctionPtr)]Protobuf.ProtobufLogHandler logHandler);
 
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern void mp_api_SerializedProto__delete(IntPtr serializedProto);

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/Framework/Format/ImageFrame_Unsafe.cs

@@ -13,7 +13,7 @@ public static extern MpReturnCode mp_ImageFrame__ui_i_i_ui(
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern MpReturnCode mp_ImageFrame__ui_i_i_i_Pui8_PF(
         ImageFormat.Format format, int width, int height, int widthStep, IntPtr pixelData,
-        [MarshalAs(UnmanagedType.FunctionPtr)]IntPtr deleter, out IntPtr imageFrame);
+        [MarshalAs(UnmanagedType.FunctionPtr)]ImageFrame.Deleter deleter, out IntPtr imageFrame);
 
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern void mp_ImageFrame__delete(IntPtr imageFrame);

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/Gpu/GlCalculatorHelper_Unsafe.cs

@@ -14,7 +14,7 @@ internal static partial class UnsafeNativeMethods {
 
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern MpReturnCode mp_GlCalculatorHelper__RunInGlContext__PF(
-        IntPtr glCalculatorHelper, [MarshalAs(UnmanagedType.FunctionPtr)]IntPtr glFunc, out IntPtr status);
+        IntPtr glCalculatorHelper, [MarshalAs(UnmanagedType.FunctionPtr)]GlCalculatorHelper.NativeGlStatusFunction glFunc, out IntPtr status);
 
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern MpReturnCode mp_GlCalculatorHelper__CreateSourceTexture__Rif(

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/Gpu/GlTextureBuffer_Unsafe.cs

@@ -12,6 +12,7 @@ internal static partial class UnsafeNativeMethods {
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern MpReturnCode mp_SharedGlTextureBuffer__ui_ui_i_i_ui_PF_PSgc(
         UInt32 target, UInt32 name, int width, int height, GpuBufferFormat format,
-        [MarshalAs(UnmanagedType.FunctionPtr)]IntPtr deletionCallback, IntPtr producerContext, out IntPtr sharedGlTextureBuffer);
+        [MarshalAs(UnmanagedType.FunctionPtr)]GlTextureBuffer.DeletionCallback deletionCallback,
+        IntPtr producerContext, out IntPtr sharedGlTextureBuffer);
   }
 }

Assets/MediaPipe/SDK/Scripts/PInvoke/NativeMethods/Util/ResourceManager_Safe.cs

@@ -1,11 +1,10 @@
-using System;
-using System.Diagnostics.Contracts;
 using System.Runtime.InteropServices;
 
 namespace Mediapipe {
   internal static partial class SafeNativeMethods {
     [DllImport (MediaPipeLibrary, ExactSpelling = true)]
     public static extern void mp_api__PrepareResourceManager(
-        [MarshalAs(UnmanagedType.FunctionPtr)]IntPtr resolver,[MarshalAs(UnmanagedType.FunctionPtr)]IntPtr handler);
+        [MarshalAs(UnmanagedType.FunctionPtr)]ResourceManager.CacheFilePathResolver resolver,
+        [MarshalAs(UnmanagedType.FunctionPtr)]ResourceManager.ReadFileHandler handler);
   }
 }

Assets/MediaPipe/SDK/Scripts/Util/ResourceManager.cs

@@ -1,29 +1,18 @@
 using System;
-using System.Runtime.InteropServices;
 
 namespace Mediapipe {
   public abstract class ResourceManager {
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-    private delegate string CacheFilePathResolver(string path);
-    private readonly CacheFilePathResolver cacheFilePathResolver;
+    public delegate string CacheFilePathResolver(string path);
+    public readonly CacheFilePathResolver cacheFilePathResolver;
 
-    [UnmanagedFunctionPointer(CallingConvention.StdCall)]
-    private delegate bool ReadFileHandler(string path, IntPtr dst);
-    private readonly ReadFileHandler readFileHandler;
+    public delegate bool ReadFileHandler(string path, IntPtr dst);
+    public readonly ReadFileHandler readFileHandler;
 
     protected ResourceManager() {
       cacheFilePathResolver = CacheFileFromAsset;
       readFileHandler = ReadFile;
     }
 
-    public IntPtr GetCacheFilePathResolverPtr() {
-      return Marshal.GetFunctionPointerForDelegate(cacheFilePathResolver);
-    }
-
-    public IntPtr GetReadFileHandlerPtr() {
-      return Marshal.GetFunctionPointerForDelegate(readFileHandler);
-    }
-
     protected abstract string CacheFileFromAsset(string assetPath);
 
     protected abstract bool ReadFile(string path, IntPtr dst);

Assets/MediaPipe/SDK/Scripts/Util/ResourceUtil.cs

@@ -1,9 +1,7 @@
-using System;
-
 namespace Mediapipe {
   public class ResourceUtil {
     public static void InitializeResourceManager(ResourceManager resourceManager) {
-      SafeNativeMethods.mp_api__PrepareResourceManager(resourceManager.GetCacheFilePathResolverPtr(), resourceManager.GetReadFileHandlerPtr());
+      SafeNativeMethods.mp_api__PrepareResourceManager(resourceManager.cacheFilePathResolver, resourceManager.readFileHandler);
     }
   }
 }