Remove OSX FileStream Lock/Unlock

src/mscorlib/System.Private.CoreLib.csproj

@@ -858,6 +858,12 @@
     <MscorlibSources Include="$(CoreFxSourcesRoot)\Microsoft\Win32\SafeHandles\SafeFileHandle.Unix.cs" />
     <MscorlibSources Include="$(CoreFxSourcesRoot)\System\IO\FileStream.Unix.cs" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetsUnix)' == 'true' and '$(TargetsOSX)' == 'true'">
+    <MscorlibSources Include="$(CoreFxSourcesRoot)\System\IO\FileStream.OSX.cs" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetsUnix)' == 'true' and '$(TargetsOSX)' != 'true'">
+    <MscorlibSources Include="$(CoreFxSourcesRoot)\System\IO\FileStream.Linux.cs" />
+  </ItemGroup>
   <ItemGroup Condition="'$(TargetsUnix)' != 'true'">
     <MscorlibSources Include="$(CoreFxSourcesRoot)\Microsoft\Win32\SafeHandles\SafeFileHandle.Windows.cs" />
     <MscorlibSources Include="$(CoreFxSourcesRoot)\System\IO\FileStream.Win32.cs" />

src/mscorlib/corefx/System/IO/FileStream.Linux.cs

@@ -0,0 +1,30 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Win32.SafeHandles;
+using System.Diagnostics;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace System.IO
+{
+    public partial class FileStream : Stream
+    {
+        /// <summary>Prevents other processes from reading from or writing to the FileStream.</summary>
+        /// <param name="position">The beginning of the range to lock.</param>
+        /// <param name="length">The range to be locked.</param>
+        private void LockInternal(long position, long length)
+        {
+            CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_WRLCK));
+        }
+
+        /// <summary>Allows access by other processes to all or part of a file that was previously locked.</summary>
+        /// <param name="position">The beginning of the range to unlock.</param>
+        /// <param name="length">The range to be unlocked.</param>
+        private void UnlockInternal(long position, long length)
+        {
+            CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_UNLCK));
+        }
+    }
+}

src/mscorlib/corefx/System/IO/FileStream.OSX.cs

@@ -0,0 +1,19 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace System.IO
+{
+    public partial class FileStream : Stream
+    {
+        private void LockInternal(long position, long length)
+        {
+            throw new PlatformNotSupportedException(Environment.GetResourceString("PlatformNotSupported_OSXFileLocking"));
+        }
+
+        private void UnlockInternal(long position, long length)
+        {
+            throw new PlatformNotSupportedException(Environment.GetResourceString("PlatformNotSupported_OSXFileLocking"));
+        }
+    }
+}

src/mscorlib/corefx/System/IO/FileStream.Unix.cs

@@ -796,22 +796,6 @@ public override void WriteByte(byte value) // avoids an array allocation in the
             }
         }
 
-        /// <summary>Prevents other processes from reading from or writing to the FileStream.</summary>
-        /// <param name="position">The beginning of the range to lock.</param>
-        /// <param name="length">The range to be locked.</param>
-        private void LockInternal(long position, long length)
-        {
-            CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_WRLCK));
-        }
-
-        /// <summary>Allows access by other processes to all or part of a file that was previously locked.</summary>
-        /// <param name="position">The beginning of the range to unlock.</param>
-        /// <param name="length">The range to be unlocked.</param>
-        private void UnlockInternal(long position, long length)
-        {
-            CheckFileCall(Interop.Sys.LockFileRegion(_fileHandle, position, length, Interop.Sys.LockType.F_UNLCK));
-        }
-
         /// <summary>Sets the current position of this stream to the given value.</summary>
         /// <param name="offset">The point relative to origin from which to begin seeking. </param>
         /// <param name="origin">

src/mscorlib/src/System.Private.CoreLib.txt

@@ -1719,6 +1719,8 @@ event_Barrier_PhaseFinished=Barrier finishing phase {1}.
 ; Unix threading
 PlatformNotSupported_NamedSynchronizationPrimitives=The named version of this synchronization primitive is not supported on this platform.
 PlatformNotSupported_NamedSyncObjectWaitAnyWaitAll=Wait operations on multiple wait handles including a named synchronization primitive are not supported on this platform.
+; OSX File locking
+PlatformNotSupported_OSXFileLocking=Locking/unlocking file regions is not supported on this platform. Use FileShare on the entire file instead.
 #endif
 
 ;