Merge pull request #1998 from shimat/feature/internal-safehandle-null-1938

Internal: remove dead KeepAlive/ElemPtr, add OpenCvSafeHandle.Null for optional args

Author: shimat

src/OpenCvSharp/Fundamentals/OpenCvSafeHandle.cs

@@ -44,4 +44,11 @@ protected OpenCvSafeHandle(IntPtr existingHandle, bool ownsHandle)
 
     /// <inheritdoc />
     public override bool IsInvalid => handle == IntPtr.Zero;
+
+    /// <summary>
+    /// A non-owning handle wrapping a null native pointer. Pass this for an optional
+    /// SafeHandle-typed P/Invoke argument (e.g. a mask) when the caller has none, instead
+    /// of overloading the parameter type with a plain <see cref="IntPtr"/>.
+    /// </summary>
+    public static OpenCvSafeHandle Null { get; } = new OpenCvPtrSafeHandle(IntPtr.Zero, ownsHandle: false, releaseAction: null);
 }

src/OpenCvSharp/Internal/PInvoke/NativeMethods/NativeMethods_line_descriptor.cs

@@ -29,7 +29,7 @@ public static partial ExceptionStatus line_descriptor_LSDDetector_new2(
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus line_descriptor_LSDDetector_detect1(
-        OpenCvSafeHandle obj, IntPtr image, IntPtr keypoints, int scale, int numOctaves, IntPtr mask);
+        OpenCvSafeHandle obj, IntPtr image, IntPtr keypoints, int scale, int numOctaves, OpenCvSafeHandle mask);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus line_descriptor_LSDDetector_detect2(

src/OpenCvSharp/Internal/PInvoke/NativeMethods/NativeMethods_stdvector.cs

@@ -282,8 +282,6 @@ static partial class NativeMethods
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial nuint vector_Mat_getSize(OpenCvSafeHandle vector);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial IntPtr vector_Mat_getPointer(OpenCvSafeHandle vector);
-    [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial void vector_Mat_delete(IntPtr vector);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial void vector_Mat_assignToArray(OpenCvSafeHandle vector, [MarshalAs(UnmanagedType.LPArray)] IntPtr[] arr);

src/OpenCvSharp/Internal/PInvoke/NativeMethods/core/NativeMethods_core_FileNode.cs

@@ -80,9 +80,9 @@ public static partial ExceptionStatus core_FileNode_readRaw(
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus core_FileNode_read_String(OpenCvSafeHandle node, IntPtr value, [MarshalAs(UnmanagedType.LPStr)] string? defaultValue);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial ExceptionStatus core_FileNode_read_Mat(OpenCvSafeHandle node, IntPtr mat, IntPtr defaultMat);
+    public static partial ExceptionStatus core_FileNode_read_Mat(OpenCvSafeHandle node, IntPtr mat, OpenCvSafeHandle defaultMat);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial ExceptionStatus core_FileNode_read_SparseMat(OpenCvSafeHandle node, IntPtr mat, IntPtr defaultMat);
+    public static partial ExceptionStatus core_FileNode_read_SparseMat(OpenCvSafeHandle node, IntPtr mat, OpenCvSafeHandle defaultMat);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus core_FileNode_read_vectorOfKeyPoint(OpenCvSafeHandle node, IntPtr keypoints);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]

src/OpenCvSharp/Internal/PInvoke/NativeMethods/core/NativeMethods_core_Mat.cs

@@ -107,9 +107,9 @@ public static partial ExceptionStatus core_Mat_ones_MatShape(
     public static partial ExceptionStatus core_Mat_assignTo(OpenCvSafeHandle self, IntPtr m, int type);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial ExceptionStatus core_Mat_setTo_Scalar(OpenCvSafeHandle self, Scalar value, IntPtr mask);
+    public static partial ExceptionStatus core_Mat_setTo_Scalar(OpenCvSafeHandle self, Scalar value, OpenCvSafeHandle mask);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    internal static partial ExceptionStatus core_Mat_setTo_InputArray(OpenCvSafeHandle self, in InputArrayProxy value, IntPtr mask);
+    internal static partial ExceptionStatus core_Mat_setTo_InputArray(OpenCvSafeHandle self, in InputArrayProxy value, OpenCvSafeHandle mask);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus core_Mat_reshape1(

src/OpenCvSharp/Internal/PInvoke/NativeMethods/core/NativeMethods_core_UMat.cs

@@ -84,9 +84,9 @@ static partial class NativeMethods
     public static partial ExceptionStatus core_UMat_assignTo(OpenCvSafeHandle self, IntPtr m, int type);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial ExceptionStatus core_UMat_setTo_Scalar(OpenCvSafeHandle self, Scalar value, IntPtr mask);
+    public static partial ExceptionStatus core_UMat_setTo_Scalar(OpenCvSafeHandle self, Scalar value, OpenCvSafeHandle mask);
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    internal static partial ExceptionStatus core_UMat_setTo_InputArray(OpenCvSafeHandle self, in InputArrayProxy value, IntPtr mask);
+    internal static partial ExceptionStatus core_UMat_setTo_InputArray(OpenCvSafeHandle self, in InputArrayProxy value, OpenCvSafeHandle mask);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus core_UMat_reshape1(

src/OpenCvSharp/Internal/PInvoke/NativeMethods/stitching/NativeMethods_stitching_Matchers.cs

@@ -45,7 +45,7 @@ public static partial ExceptionStatus stitching_FeaturesMatcher_apply(
     public static partial ExceptionStatus stitching_FeaturesMatcher_apply2(
         OpenCvSafeHandle obj,
         WImageFeatures[] features, int featuresSize,
-        IntPtr mask,
+        OpenCvSafeHandle mask,
         IntPtr outSrcImgIdx,
         IntPtr outDstImgIdx,
         IntPtr outMatches,

src/OpenCvSharp/Internal/PInvoke/NativeMethods/video/NativeMethods_video_tracking.cs

@@ -79,7 +79,7 @@ public static partial ExceptionStatus video_KalmanFilter_init(OpenCvSafeHandle o
     public static partial ExceptionStatus video_KalmanFilter_delete(IntPtr obj);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
-    public static partial ExceptionStatus video_KalmanFilter_predict(OpenCvSafeHandle obj, IntPtr control, out IntPtr returnValue);
+    public static partial ExceptionStatus video_KalmanFilter_predict(OpenCvSafeHandle obj, OpenCvSafeHandle control, out IntPtr returnValue);
 
     [LibraryImport(DllExtern), UnmanagedCallConv(CallConvs = [typeof(CallConvCdecl)])]
     public static partial ExceptionStatus video_KalmanFilter_correct(OpenCvSafeHandle obj, IntPtr measurement, out IntPtr returnValue);

src/OpenCvSharp/Internal/Vectors/VectorOfMat.cs

@@ -72,20 +72,6 @@ public int Size
         }
     }
 
-    /// <summary>
-    /// &amp;vector[0]
-    /// </summary>
-    public IntPtr ElemPtr
-    {
-        get
-        {
-            var res = NativeMethods.vector_Mat_getPointer(Handle);
-            // Returns an interior pointer into this vector; keep it alive for the caller's dereference.
-            GC.KeepAlive(this);
-            return res;
-        }
-    }
-
     /// <summary>
     /// Converts std::vector to managed array
     /// </summary>

src/OpenCvSharp/Modules/core/FileNode.cs

@@ -512,8 +512,7 @@ public Mat ReadMat(Mat? defaultMat = null)
         try
         {
             NativeMethods.HandleException(
-                NativeMethods.core_FileNode_read_Mat(Handle, value.CvPtr, Cv2.ToPtr(defaultMat)));
-            GC.KeepAlive(defaultMat);
+                NativeMethods.core_FileNode_read_Mat(Handle, value.CvPtr, defaultMat?.Handle ?? OpenCvSafeHandle.Null));
         }
         catch
         {
@@ -534,8 +533,7 @@ public SparseMat ReadSparseMat(SparseMat? defaultMat = null)
         try
         {
             NativeMethods.HandleException(
-                NativeMethods.core_FileNode_read_SparseMat(Handle, value.CvPtr, Cv2.ToPtr(defaultMat)));
-            GC.KeepAlive(defaultMat);
+                NativeMethods.core_FileNode_read_SparseMat(Handle, value.CvPtr, defaultMat?.Handle ?? OpenCvSafeHandle.Null));
         }
         catch
         {