Wes xx mediapipe integration

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

@@ -0,0 +1,102 @@
+// Copyright (c) 2021 homuler
+//
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+using System;
+using System.Runtime.InteropServices;
+
+namespace Mediapipe
+{
+  public abstract class MpResourceHandle : DisposableObject, IMpResourceHandle
+  {
+    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) { }
+
+    protected MpResourceHandle(IntPtr ptr, bool isOwner = true) : base(isOwner)
+    {
+      this.ptr = ptr;
+    }
+
+    #region IMpResourceHandle
+    public IntPtr mpPtr
+    {
+      get
+      {
+        ThrowIfDisposed();
+        return ptr;
+      }
+    }
+
+    public void ReleaseMpResource()
+    {
+      if (OwnsResource())
+      {
+        DeleteMpPtr();
+      }
+      ReleaseMpPtr();
+      TransferOwnership();
+    }
+
+    public bool OwnsResource()
+    {
+      return isOwner && IsResourcePresent();
+    }
+    #endregion
+
+    protected override void DisposeUnmanaged()
+    {
+      if (OwnsResource())
+      {
+        DeleteMpPtr();
+      }
+      ReleaseMpPtr();
+      base.DisposeUnmanaged();
+    }
+
+    /// <summary>
+    ///   Forgets the pointer address.
+    ///   After calling this method, <see ref="OwnsResource" /> will return false.
+    /// </summary>
+    protected void ReleaseMpPtr()
+    {
+      ptr = IntPtr.Zero;
+    }
+
+    /// <summary>
+    ///   Release the memory (call `delete` or `delete[]`) whether or not it owns it.
+    /// </summary>
+    /// <remarks>In most cases, this method should not be called directly</remarks>
+    protected abstract void DeleteMpPtr();
+
+    protected delegate MpReturnCode StringOutFunc(IntPtr ptr, out IntPtr strPtr);
+    protected string MarshalStringFromNative(StringOutFunc f)
+    {
+      f(mpPtr, out var strPtr).Assert();
+      GC.KeepAlive(this);
+
+      var str = Marshal.PtrToStringAnsi(strPtr);
+      UnsafeNativeMethods.delete_array__PKc(strPtr);
+
+      return str;
+    }
+
+    protected bool IsResourcePresent()
+    {
+      return ptr != IntPtr.Zero;
+    }
+  }
+}