porting shell from nuget to local

src/Shared/Microsoft.Windows.Shell/Standard/PROPVARIANT.cs

@@ -0,0 +1,94 @@
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Runtime.InteropServices;
+
+namespace Standard
+{
+	[SuppressMessage("Microsoft.Performance", "CA1812:AvoidUninstantiatedInternalClasses")]
+	[StructLayout(LayoutKind.Explicit)]
+	internal class PROPVARIANT : IDisposable
+	{
+		[SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+		public VarEnum VarType
+		{
+			get
+			{
+				return (VarEnum)this.vt;
+			}
+		}
+
+		[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
+		public string GetValue()
+		{
+			if (this.vt == 31)
+			{
+				return Marshal.PtrToStringUni(this.pointerVal);
+			}
+			return null;
+		}
+
+		public void SetValue(bool f)
+		{
+			this.Clear();
+			this.vt = 11;
+			this.boolVal = (short)(f ? -1 : 0);
+		}
+
+		[SuppressMessage("Microsoft.Security", "CA2122:DoNotIndirectlyExposeMethodsWithLinkDemands")]
+		public void SetValue(string val)
+		{
+			this.Clear();
+			this.vt = 31;
+			this.pointerVal = Marshal.StringToCoTaskMemUni(val);
+		}
+
+		public void Clear()
+		{
+			PROPVARIANT.NativeMethods.PropVariantClear(this);
+		}
+
+		public void Dispose()
+		{
+			this.Dispose(true);
+			GC.SuppressFinalize(this);
+		}
+
+		~PROPVARIANT()
+		{
+			this.Dispose(false);
+		}
+
+		[SuppressMessage("Microsoft.Usage", "CA1801:ReviewUnusedParameters", MessageId = "disposing")]
+		private void Dispose(bool disposing)
+		{
+			this.Clear();
+		}
+
+		[SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
+		[FieldOffset(0)]
+		private ushort vt;
+
+		[SuppressMessage("Microsoft.Reliability", "CA2006:UseSafeHandleToEncapsulateNativeResources")]
+		[SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
+		[FieldOffset(8)]
+		private IntPtr pointerVal;
+
+		[SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
+		[FieldOffset(8)]
+		private byte byteVal;
+
+		[SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
+		[FieldOffset(8)]
+		private long longVal;
+
+		[SuppressMessage("Microsoft.Performance", "CA1823:AvoidUnusedPrivateFields")]
+		[FieldOffset(8)]
+		private short boolVal;
+
+		private static class NativeMethods
+		{
+			[DllImport("ole32.dll")]
+			internal static extern HRESULT PropVariantClear(PROPVARIANT pvar);
+		}
+	}
+}