Process info standard input encoding (#25990)

* Add StandardInputEncoding to ProcessStartInfo

* Add test coverage for ProcessStartInfo.StandardInputEncoding

* Add unix support for ProcessStartInfo.StandardInputEncoding

* Clean up StandardInputEncoding implementation

* Incorporate feedback from #25990 for ProcessStartInfo.StandardInputEncoding feature.

* ProcessStartInfo.StandardInputEncoding: skip two unsupported tests on UAP

Author: madelson

src/System.Diagnostics.Process/ref/System.Diagnostics.Process.cs

@@ -170,6 +170,7 @@ public ProcessStartInfo(string fileName, string arguments) { }
         public bool RedirectStandardInput { get { throw null; } set { } }
         public bool RedirectStandardOutput { get { throw null; } set { } }
         public System.Text.Encoding StandardErrorEncoding { get { throw null; } set { } }
+        public System.Text.Encoding StandardInputEncoding { get { throw null; } set { } }
         public System.Text.Encoding StandardOutputEncoding { get { throw null; } set { } }
         public string UserName { get { throw null; } set { } }
         public bool UseShellExecute { get { throw null; } set { } }

src/System.Diagnostics.Process/src/Resources/Strings.resx

@@ -309,4 +309,7 @@
   <data name="GetProcessInfoNotSupported" xml:space="preserve">
     <value>Retrieving information about local processes is not supported on this platform.</value>
   </data>
+  <data name="StandardInputEncodingNotAllowed" xml:space="preserve">
+    <value>StandardInputEncoding is only supported when standard input is redirected.</value>
+  </data>
 </root>

src/System.Diagnostics.Process/src/System/Diagnostics/Process.Unix.cs

@@ -317,7 +317,7 @@ private bool StartCore(ProcessStartInfo startInfo)
             {
                 Debug.Assert(stdinFd >= 0);
                 _standardInput = new StreamWriter(OpenStream(stdinFd, FileAccess.Write),
-                    s_utf8NoBom, StreamBufferSize) { AutoFlush = true };
+                    startInfo.StandardInputEncoding ?? s_utf8NoBom, StreamBufferSize) { AutoFlush = true };
             }
             if (startInfo.RedirectStandardOutput)
             {

src/System.Diagnostics.Process/src/System/Diagnostics/Process.Win32.cs

@@ -34,6 +34,9 @@ private unsafe bool StartWithShellExecuteEx(ProcessStartInfo startInfo)
             if (startInfo.RedirectStandardInput || startInfo.RedirectStandardOutput || startInfo.RedirectStandardError)
                 throw new InvalidOperationException(SR.CantRedirectStreams);
 
+            if (startInfo.StandardInputEncoding != null)
+                throw new InvalidOperationException(SR.StandardInputEncodingNotAllowed);
+
             if (startInfo.StandardErrorEncoding != null)
                 throw new InvalidOperationException(SR.StandardErrorEncodingNotAllowed);
 

src/System.Diagnostics.Process/src/System/Diagnostics/Process.Windows.cs

@@ -633,7 +633,7 @@ private bool StartWithCreateProcess(ProcessStartInfo startInfo)
 
             if (startInfo.RedirectStandardInput)
             {
-                Encoding enc = GetEncoding((int)Interop.Kernel32.GetConsoleCP());
+                Encoding enc = startInfo.StandardInputEncoding ?? GetEncoding((int)Interop.Kernel32.GetConsoleCP());
                 _standardInput = new StreamWriter(new FileStream(standardInputWritePipeHandle, FileAccess.Write, 4096, false), enc, 4096);
                 _standardInput.AutoFlush = true;
             }

src/System.Diagnostics.Process/src/System/Diagnostics/Process.cs

@@ -1156,6 +1156,10 @@ public bool Start()
             {
                 throw new InvalidOperationException(SR.FileNameMissing);
             }
+            if (startInfo.StandardInputEncoding != null && !startInfo.RedirectStandardInput)
+            {
+                throw new InvalidOperationException(SR.StandardInputEncodingNotAllowed);
+            }
             if (startInfo.StandardOutputEncoding != null && !startInfo.RedirectStandardOutput)
             {
                 throw new InvalidOperationException(SR.StandardOutputEncodingNotAllowed);

src/System.Diagnostics.Process/src/System/Diagnostics/ProcessStartInfo.cs

@@ -95,8 +95,10 @@ public IDictionary<string, string> Environment
         public bool RedirectStandardOutput { get; set; }
         public bool RedirectStandardError { get; set; }
 
-        public Encoding StandardErrorEncoding { get; set; }
+        public Encoding StandardInputEncoding { get; set; }
 
+        public Encoding StandardErrorEncoding { get; set; }
+        
         public Encoding StandardOutputEncoding { get; set; }
 
         /// <devdoc>

src/System.Diagnostics.Process/tests/Configurations.props

@@ -6,6 +6,8 @@
       netstandard-Unix;
       uap-Windows_NT;
       uapaot-Windows_NT;
+      netcoreapp-Windows_NT;
+      netcoreapp-Unix;
     </BuildConfigurations>
   </PropertyGroup>
 </Project>

src/System.Diagnostics.Process/tests/ProcessStreamReadTests.cs

@@ -10,7 +10,7 @@
 
 namespace System.Diagnostics.Tests
 {
-    public class ProcessStreamReadTests : ProcessTestBase
+    public partial class ProcessStreamReadTests : ProcessTestBase
     {
         [Fact]
         public void TestSyncErrorStream()

src/System.Diagnostics.Process/tests/ProcessStreamReadTests.netcoreapp.cs

@@ -0,0 +1,61 @@
+// 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 System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace System.Diagnostics.Tests
+{
+    public partial class ProcessStreamReadTests : ProcessTestBase
+    {
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "RemotelyInvokable.ReadLineWithCustomEncodingWriteLineWithUtf8 is not supported on uap")]
+        public void TestCustomStandardInputEncoding()
+        {
+            var process = CreateProcessPortable(RemotelyInvokable.ReadLineWithCustomEncodingWriteLineWithUtf8, Encoding.UTF32.WebName);
+            process.StartInfo.RedirectStandardInput = true;
+            process.StartInfo.StandardInputEncoding = Encoding.UTF32;
+            process.StartInfo.RedirectStandardOutput = true;
+            process.StartInfo.StandardOutputEncoding = Encoding.UTF8;
+            process.Start();
+
+            const string TestLine = "\U0001f627\U0001f62e\U0001f62f";
+            process.StandardInput.WriteLine(TestLine);
+            process.StandardInput.Close();
+
+            var output = process.StandardOutput.ReadLine();
+            Assert.Equal(TestLine, output);
+
+            Assert.True(process.WaitForExit(WaitInMS));
+            Assert.Equal(RemotelyInvokable.SuccessExitCode, process.ExitCode);
+        }
+
+        [Fact]
+        [SkipOnTargetFramework(TargetFrameworkMonikers.Uap, "RemotelyInvokable.ReadLineWithCustomEncodingWriteLineWithUtf8 is not supported on uap")]
+        public void TestMismatchedStandardInputEncoding()
+        {
+            var process = CreateProcessPortable(RemotelyInvokable.ReadLineWithCustomEncodingWriteLineWithUtf8, Encoding.UTF32.WebName);
+            process.StartInfo.RedirectStandardInput = true;
+            // incorrect: the process will be writing in UTF-32
+            process.StartInfo.StandardInputEncoding = Encoding.ASCII;
+            process.StartInfo.RedirectStandardOutput = true;
+            process.StartInfo.StandardOutputEncoding = Encoding.UTF8;
+            process.Start();
+
+            const string TestLine = "\U0001f627\U0001f62e\U0001f62f";
+            process.StandardInput.WriteLine(TestLine);
+            process.StandardInput.Close();
+
+            var output = process.StandardOutput.ReadLine();
+            Assert.NotEqual(TestLine, output);
+
+            Assert.True(process.WaitForExit(WaitInMS));
+            Assert.Equal(RemotelyInvokable.SuccessExitCode, process.ExitCode);
+        }
+    }
+}