Imported Upstream version 6.4.0.137

Former-commit-id: 943baa9f16a098c33e129777827f3a9d20da00d6

mcs/class/System.Private.CoreLib/System.Threading/WaitHandle.cs

@@ -0,0 +1,43 @@
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+namespace System.Threading
+{
+	partial class WaitHandle
+	{
+		[MethodImplAttribute(MethodImplOptions.InternalCall)]
+		unsafe static extern int Wait_internal(IntPtr* handles, int numHandles, bool waitAll, int ms);
+
+		static int WaitOneCore (IntPtr waitHandle, int millisecondsTimeout)
+		{
+			unsafe {
+				return Wait_internal (&waitHandle, 1, false, millisecondsTimeout);
+			}
+		}
+
+		[MethodImpl (MethodImplOptions.InternalCall)]
+		static extern int SignalAndWait_Internal (IntPtr waitHandleToSignal, IntPtr waitHandleToWaitOn, int millisecondsTimeout);
+
+		const int ERROR_TOO_MANY_POSTS = 0x12A;
+		const int ERROR_NOT_OWNED_BY_CALLER = 0x12B;
+
+		static int SignalAndWaitCore (IntPtr waitHandleToSignal, IntPtr waitHandleToWaitOn, int millisecondsTimeout)
+		{
+			int ret = SignalAndWait_Internal (waitHandleToSignal, waitHandleToWaitOn, millisecondsTimeout);
+			if (ret == ERROR_TOO_MANY_POSTS)
+				throw new InvalidOperationException (SR.Threading_WaitHandleTooManyPosts);
+			if (ret == ERROR_NOT_OWNED_BY_CALLER)
+				throw new ApplicationException("Attempt to release mutex not owned by caller");
+			return ret;
+		}
+
+		internal static int WaitMultipleIgnoringSyncContext (Span<IntPtr> waitHandles, bool waitAll, int millisecondsTimeout)
+		{
+			unsafe {
+				fixed (IntPtr* handles = &MemoryMarshal.GetReference (waitHandles)) {
+					return Wait_internal (handles, waitHandles.Length, waitAll, millisecondsTimeout);
+				}
+			}
+		}
+	}
+}