From 9ff0da9317774e6d3c232dbc7bc55793be223da4 Mon Sep 17 00:00:00 2001
From: Martin <mautner@vrvis.at>
Date: Wed, 4 Sep 2024 12:04:15 +0200
Subject: [PATCH] [FSharp] Move pin utilities to modules; add pinArri, temp

---
 .../Utilities/Interop/FSLibExtensions.fs      | 20 +++++++++++++++++
 src/Aardvark.Base.FSharp/Utilities/Native.fs  | 22 ++++++++++---------
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/src/Aardvark.Base.FSharp/Utilities/Interop/FSLibExtensions.fs b/src/Aardvark.Base.FSharp/Utilities/Interop/FSLibExtensions.fs
index cd4fc62c..99391665 100644
--- a/src/Aardvark.Base.FSharp/Utilities/Interop/FSLibExtensions.fs
+++ b/src/Aardvark.Base.FSharp/Utilities/Interop/FSLibExtensions.fs
@@ -266,6 +266,26 @@ module Prelude =
             let l = int64 <| sizeof<'a> * count
             new System.IO.UnmanagedMemoryStream(cast ptr, l,l, FileAccess.ReadWrite) :> _
 
+        /// Pins the given value and invokes the action with the native pointer.
+        /// Note: Use a fixed expression with a byref if writing to the original location is required.
+        let inline pin<'T, 'U when 'T : unmanaged> ([<InlineIfLambda>] action: nativeptr<'T> -> 'U) (value: 'T) =
+            use ptr = fixed &value
+            action ptr
+
+        /// Pins the given array and invokes the action with the native pointer.
+        let inline pinArr<'T, 'U when 'T : unmanaged> ([<InlineIfLambda>] action: nativeptr<'T> -> 'U) (array: 'T[])  =
+            use ptr = fixed array
+            action ptr
+
+        /// Pins the given array at the given index and invokes the action with the native pointer.
+        let inline pinArri<'T, 'U when 'T : unmanaged> ([<InlineIfLambda>] action: nativeptr<'T> -> 'U) (index: int) (array: 'T[])  =
+            use ptr = fixed &array.[index]
+            action ptr
+
+        /// Allocates a temporary native pointer and invokes the action.
+        let inline temp<'T, 'U when 'T : unmanaged> ([<InlineIfLambda>] action: nativeptr<'T> -> 'U) =
+            pin action Unchecked.defaultof<'T>
+
         module Operators =
 
             let ( &+ ) (ptr : nativeptr<'a>) (count : int) =
diff --git a/src/Aardvark.Base.FSharp/Utilities/Native.fs b/src/Aardvark.Base.FSharp/Utilities/Native.fs
index 2e09818b..1655542a 100644
--- a/src/Aardvark.Base.FSharp/Utilities/Native.fs
+++ b/src/Aardvark.Base.FSharp/Utilities/Native.fs
@@ -127,6 +127,12 @@ module NativeUtilities =
         let inline set<'a when 'a : unmanaged> (ptr : nativeint) (index : int) (value : 'a)=
             NativePtr.set (NativePtr.ofNativeInt<'a> ptr) index value
 
+        /// Pins the given object and invokes the action with its address.
+        let inline pin ([<InlineIfLambda>] action: nativeint -> 'T) (value: obj) =
+            let gc = GCHandle.Alloc(value, GCHandleType.Pinned)
+            try action <| gc.AddrOfPinnedObject()
+            finally gc.Free()
+
     type Marshal with
         static member Copy(source : nativeint, destination : nativeint, length : unativeint) =
             match os with
@@ -174,21 +180,17 @@ module NativeUtilities =
         static member inline Compare(source : nativeint, destination : nativeint, length : 'a) =
             Marshal.Compare(source, destination, unativeint length)
 
-
+    [<Obsolete("Use NativeInt.pin instead.")>]
     let pinned (a : obj) f =
-        let gc = GCHandle.Alloc(a, GCHandleType.Pinned)
-        try
-            f ( gc.AddrOfPinnedObject() )
-        finally
-            gc.Free()
+        NativeInt.pin f a
 
+    [<Obsolete("Use NativePtr.pin instead.")>]
     let inline pin ([<InlineIfLambda>] f: nativeptr<'T> -> 'U) (value: 'T) =
-        use ptr = fixed &value
-        f ptr
+        NativePtr.pin f value
 
+    [<Obsolete("Use NativePtr.pinArr instead.")>]
     let inline pinArr ([<InlineIfLambda>] f: nativeptr<'T> -> 'U) (array: 'T[])  =
-        use ptr = fixed array
-        f ptr
+        NativePtr.pinArr f array
 
 [<AutoOpen>]
 module MarshalDelegateExtensions =