Metal: Buffers Take 2 (#21)

* Basic BufferManager

* Start Scoped Command Buffers

* Fences stuff

* Remember to cleanup sync manager

* Auto, Command Buffer Dependants

* Cleanup

* Cleanup + Fix Texture->Buffer Copies

* Slow buffer upload

* Cleanup + Rework TextureBuffer

* Don’t get unsafe

* Cleanup

* Goddamn it

* Staging Buffer + Interrupt Action + Flush

src/Ryujinx.Graphics.Metal/FenceHolder.cs

@@ -0,0 +1,77 @@
+using SharpMetal.Metal;
+using System;
+using System.Runtime.Versioning;
+using System.Threading;
+
+namespace Ryujinx.Graphics.Metal
+{
+    [SupportedOSPlatform("macos")]
+    public class FenceHolder : IDisposable
+    {
+        private MTLCommandBuffer _fence;
+        private int _referenceCount;
+        private bool _disposed;
+
+        public FenceHolder(MTLCommandBuffer fence)
+        {
+            _fence = fence;
+            _referenceCount = 1;
+        }
+
+        public MTLCommandBuffer GetUnsafe()
+        {
+            return _fence;
+        }
+
+        public bool TryGet(out MTLCommandBuffer fence)
+        {
+            int lastValue;
+            do
+            {
+                lastValue = _referenceCount;
+
+                if (lastValue == 0)
+                {
+                    fence = default;
+                    return false;
+                }
+            } while (Interlocked.CompareExchange(ref _referenceCount, lastValue + 1, lastValue) != lastValue);
+
+            fence = _fence;
+            return true;
+        }
+
+        public MTLCommandBuffer Get()
+        {
+            Interlocked.Increment(ref _referenceCount);
+            return _fence;
+        }
+
+        public void Put()
+        {
+            if (Interlocked.Decrement(ref _referenceCount) == 0)
+            {
+                _fence = default;
+            }
+        }
+
+        public void Wait()
+        {
+            _fence.WaitUntilCompleted();
+        }
+
+        public bool IsSignaled()
+        {
+            return _fence.Status == MTLCommandBufferStatus.Completed;
+        }
+
+        public void Dispose()
+        {
+            if (!_disposed)
+            {
+                Put();
+                _disposed = true;
+            }
+        }
+    }
+}