Add 'TryGetDataUnsafe' overload for 'IMemoryBufferReference' (#1673)

* Add 'IMemoryBufferReference' interop API

* Add unit test

Author: Sergio0694

src/Tests/UnitTest/TestComponentCSharp_Tests.cs

@@ -482,6 +482,26 @@ public void TestTryGetDataUnsafe()
             GC.KeepAlive(buf);
         }
 
+        [Fact]
+        public void TestTryGetDataUnsafe_MemoryBufferReference()
+        {
+            var buffer = new Windows.Foundation.MemoryBuffer(256);
+            var reference = buffer.CreateReference();
+
+            Assert.True(WindowsRuntimeMarshal.TryGetDataUnsafe(reference, out IntPtr dataPtr1, out uint capacity1));
+            Assert.True(dataPtr1 != IntPtr.Zero);
+            Assert.True(capacity1 == 256);
+
+            Assert.True(WindowsRuntimeMarshal.TryGetDataUnsafe(reference, out IntPtr dataPtr2, out uint capacity2));
+            Assert.True(dataPtr2 != IntPtr.Zero);
+            Assert.True(capacity2 == 256);
+
+            Assert.True(dataPtr1 == dataPtr2);
+
+            // Ensure the reference doesn't get collected while we use the data pointer
+            GC.KeepAlive(reference);
+        }
+
         [Fact]
         public void TestBufferTryGetArray()
         {

src/WinRT.Runtime/Interop/IID.g.cs

@@ -290,6 +290,31 @@ public static ref readonly Guid IID_IBufferByteAccess
             }
         }
 
+        /// <summary>The IID for <c>IMemoryBufferByteAccess</c> (5B0D3235-4DBA-4D44-865E-8F1D0E4FD04D).</summary>
+        public static ref readonly Guid IID_IMemoryBufferByteAccess
+        {
+            [MethodImpl(MethodImplOptions.AggressiveInlining)]   
+            get
+            {
+                ReadOnlySpan<byte> data = new byte[]
+                {
+                    0x35, 0x32, 0x0D, 0x5B,
+                    0xBA, 0x4D,
+                    0x44, 0x4D,
+                    0x86,
+                    0x5E,
+                    0x8F,
+                    0x1D,
+                    0x0E,
+                    0x4F,
+                    0xD0,
+                    0x4D
+                };
+
+                return ref Unsafe.As<byte, Guid>(ref MemoryMarshal.GetReference(data));
+            }
+        }
+
         /// <summary>The IID for <c>IContextCallback</c> (000001DA-0000-0000-C000-000000000046).</summary>
         internal static ref readonly Guid IID_IContextCallback
         {
@@ -640,7 +665,7 @@ internal static ref readonly Guid IID_WUX_INotifyCollectionChangedEventArgs
             }
         }
 
-        /// <summary>The IID for <c>WUX_MotifyCollectionChangedEventHandler</c> (8B0909DC-2005-5D93-BF8A-725F017BAA8D).</summary>
+        /// <summary>The IID for <c>MUX_NotifyCollectionChangedEventHandler</c> (8B0909DC-2005-5D93-BF8A-725F017BAA8D).</summary>
         internal static ref readonly Guid IID_MUX_NotifyCollectionChangedEventHandler
         {
             [MethodImpl(MethodImplOptions.AggressiveInlining)]   

src/WinRT.Runtime/Interop/IID.tt

@@ -33,6 +33,7 @@ var entries = new (string Name, string IID, bool IsPublic)[]
     ("IMarshal", "00000003-0000-0000-C000-000000000046", true),
     ("IBuffer", "905A0FE0-BC53-11DF-8C49-001E4FC686DA", true),
     ("IBufferByteAccess", "905A0FEF-BC53-11DF-8C49-001E4FC686DA", true),
+    ("IMemoryBufferByteAccess", "5B0D3235-4DBA-4D44-865E-8F1D0E4FD04D", true),
     ("IContextCallback", "000001DA-0000-0000-C000-000000000046", false),
     ("ICallbackWithNoReentrancyToApplicationSTA", "0A299774-3E4E-FC42-1D9D-72CEE105CA57", false),
     ("IErrorInfo", "1CF2B120-547D-101B-8E65-08002B2BD119", false),

src/cswinrt/strings/additions/Windows.Storage.Streams/WindowsRuntimeMarshal.cs

@@ -27,6 +27,8 @@ static partial class WindowsRuntimeMarshal
         /// </summary>
         /// <param name="buffer">The buffer to get the data pointer for.</param>
         /// <param name="dataPtr">The pointer to the underlying data representation of the buffer.</param>
+        /// <returns>Whether the data was successfully retrieved.</returns>
+        /// <exception cref="Exception">Thrown if invoking <c>IBufferByteAccess::Buffer</c> on the input buffer fails.</exception>
         public static unsafe bool TryGetDataUnsafe(
 #if NET
             [NotNullWhen(true)]
@@ -65,6 +67,51 @@ public static unsafe bool TryGetDataUnsafe(
             return false;
         }
 
+        /// <summary>
+        /// Returns a pointer to the underlying data representation of the <see cref="IMemoryBufferReference"/>.
+        /// Callers are responsible for ensuring that the buffer is kept alive while the pointer is in use.
+        /// </summary>
+        /// <param name="buffer">The buffer to get the data pointer for.</param>
+        /// <param name="dataPtr">The pointer to the underlying data representation of the buffer.</param>
+        /// <param name="capacity">The capacity of the buffer.</param>
+        /// <returns>Whether the data was successfully retrieved.</returns>
+        /// <exception cref="Exception">Thrown if invoking <c>IMemoryBufferByteAccess::Buffer</c> on the input buffer fails.</exception>
+        public static unsafe bool TryGetDataUnsafe(
+#if NET
+            [NotNullWhen(true)]
+#endif
+            IMemoryBufferReference? buffer, out IntPtr dataPtr, out uint capacity)
+        {
+            if (buffer == null)
+            {
+                dataPtr = IntPtr.Zero;
+                capacity = 0;
+                return false;
+            }
+
+            if (ComWrappersSupport.TryUnwrapObject(buffer, out var unwrapped) &&
+                unwrapped.TryAs(global::WinRT.Interop.IID.IID_IMemoryBufferByteAccess, out IntPtr ThisPtr) >= 0)
+            {
+                try
+                {
+                    IntPtr __retval = default;
+                    uint __capacity = 0;
+                    global::WinRT.ExceptionHelpers.ThrowExceptionForHR((*(delegate* unmanaged[Stdcall]<IntPtr, IntPtr*, uint*, int>**)ThisPtr)[3](ThisPtr, &__retval, &__capacity));
+                    dataPtr = __retval;
+                    capacity = __capacity;
+                    return true;
+                }
+                finally
+                {
+                    Marshal.Release(ThisPtr);
+                }
+            }
+
+            dataPtr = IntPtr.Zero;
+            capacity = 0;
+            return false;
+        }
+
         /// <summary>
         /// Tries to get an array segment from the underlying buffer. The return value indicates the success of the operation.
         /// </summary>