From 3cf07ff790d752411d96b7ceac6d9c3dbd967a83 Mon Sep 17 00:00:00 2001
From: Jarl Gullberg <jarl.gullberg@gmail.com>
Date: Sun, 9 Jul 2017 23:13:32 +0200
Subject: [PATCH] Broke the autorelease code out into a class and replaced the
 usage.

---
 src/OpenTK/OpenTK.csproj                      |  1 +
 .../Platform/MacOS/Cocoa/NSAutoreleasePool.cs | 34 +++++++++++++++++++
 src/OpenTK/Platform/MacOS/CocoaContext.cs     | 22 +++---------
 3 files changed, 40 insertions(+), 17 deletions(-)
 create mode 100644 src/OpenTK/Platform/MacOS/Cocoa/NSAutoreleasePool.cs

diff --git a/src/OpenTK/OpenTK.csproj b/src/OpenTK/OpenTK.csproj
index 93e68005..bf4af5e4 100644
--- a/src/OpenTK/OpenTK.csproj
+++ b/src/OpenTK/OpenTK.csproj
@@ -137,6 +137,7 @@
     <Compile Include="Platform\Egl\EglUnixContext.cs" />
     <Compile Include="Platform\Egl\EglWinContext.cs" />
     <Compile Include="Platform\Egl\EglAnglePlatformFactory.cs" />
+    <Compile Include="Platform\MacOS\Cocoa\NSAutoreleasePool.cs" />
     <Compile Include="Platform\MappedGamePadDriver.cs" />
     <Compile Include="Platform\Windows\Bindings\HidProtocol.cs" />
     <Compile Include="Platform\Windows\WinInputBase.cs" />
diff --git a/src/OpenTK/Platform/MacOS/Cocoa/NSAutoreleasePool.cs b/src/OpenTK/Platform/MacOS/Cocoa/NSAutoreleasePool.cs
new file mode 100644
index 00000000..5e7e3ee0
--- /dev/null
+++ b/src/OpenTK/Platform/MacOS/Cocoa/NSAutoreleasePool.cs
@@ -0,0 +1,34 @@
+using System;
+
+namespace OpenTK.Platform.MacOS
+{
+    /// <summary>
+    /// The <see cref="NSAutoreleasePool"/> class is a wrapper around the native objective-C NSAutoreleasePool.
+    /// In particular, this construct mimics the usage of an @autorelease block and can be used in much the same way,
+    /// only with a C# using block instead.
+    /// </summary>
+    public sealed class NSAutoreleasePool : IDisposable
+    {
+        private readonly IntPtr _autoreleasePool;
+
+        /// <summary>
+        /// Allocates and initializes a new <see cref="NSAutoreleasePool"/>.
+        /// </summary>
+        public NSAutoreleasePool()
+        {
+            _autoreleasePool = Cocoa.SendIntPtr(Class.NSAutoreleasePool, Selector.Get("alloc"));
+            _autoreleasePool = Cocoa.SendIntPtr(_autoreleasePool, Selector.Get("init"));
+        }
+
+        /// <summary>
+        /// Disposes of the <see cref="NSAutoreleasePool"/> instance, draining it.
+        /// </summary>
+        public void Dispose()
+        {
+            if (_autoreleasePool != IntPtr.Zero)
+            {
+                Cocoa.SendVoid(_autoreleasePool, Selector.Get("drain"));
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/OpenTK/Platform/MacOS/CocoaContext.cs b/src/OpenTK/Platform/MacOS/CocoaContext.cs
index 79958f63..850cd109 100644
--- a/src/OpenTK/Platform/MacOS/CocoaContext.cs
+++ b/src/OpenTK/Platform/MacOS/CocoaContext.cs
@@ -54,8 +54,6 @@ namespace OpenTK
             "/System/Library/Frameworks/OpenGL.framework/OpenGLES",
             AddImageFlags.ReturnOnError);
 
-        private IntPtr autoreleasePool;
-
         static CocoaContext()
         {
             Cocoa.Initialize();
@@ -119,10 +117,6 @@ namespace OpenTK
 
         private void CreateContext(GraphicsMode mode, CocoaWindowInfo cocoaWindow, IntPtr shareContextRef, int majorVersion, int minorVersion, bool fullscreen)
         {
-            // Create a new autorelease pool for allocations in this context (mach ports, etc)
-            autoreleasePool = Cocoa.SendIntPtr(Class.NSAutoreleasePool, Selector.Get("alloc"));
-            autoreleasePool = Cocoa.SendIntPtr(autoreleasePool, Selector.Get("init"));
-
             // Prepare attributes
             IntPtr pixelFormat = SelectPixelFormat(mode, majorVersion, minorVersion);
             if (pixelFormat == IntPtr.Zero)
@@ -346,22 +340,16 @@ namespace OpenTK
 
             Debug.Print("Disposing of Cocoa context.");
 
-            if (!NSApplication.IsUIThread)
-            {
-                return;
-            }
+            using (var pool = new NSAutoreleasePool())
+            {if (!NSApplication.IsUIThread)
+            {    return;}
 
             if (IsCurrent)
-            {
-                Cocoa.SendVoid(NSOpenGLContext, Selector.Get("clearCurrentContext"));
-            }
+            {    Cocoa.SendVoid(NSOpenGLContext, Selector.Get("clearCurrentContext"));}
             Cocoa.SendVoid(Handle.Handle, Selector.Get("clearDrawable"));
             Cocoa.SendVoid(Handle.Handle, Selector.Get("release"));
 
-            // Drain the autorelease pool for the context, closing mach ports (if there is one)
-            if (autoreleasePool != IntPtr.Zero)
-            {
-                Cocoa.SendVoid(autoreleasePool, Selector.Get("drain"));
+
             }
 
             Handle = ContextHandle.Zero;