Add support for new C# language server (lsp-roslyn)

CHANGELOG.org

@@ -1,6 +1,7 @@
 * Changelog
 ** Unreleased 9.0.1
  * Add support for GNAT Project (~gpr-mode~, ~gpr-ts-mode~).
+ * Add support for C# via the [[https://github.com/dotnet/roslyn/tree/main/src/Features/LanguageServer][Roslyn language server]].
 
 ** 9.0.0
  * Add language server config for QML (Qt Modeling Language) using qmlls.

clients/lsp-roslyn-stdpipe.ps1

@@ -0,0 +1,136 @@
+param (
+ [string]$ServerName = ".",
+ [Parameter(Mandatory=$true)][string]$PipeName
+)
+
+# Use named pipe as stdin/out
+
+$Source = @"
+using System;
+using System.Text;
+using System.IO;
+using System.IO.Pipes;
+using System.Threading.Tasks;
+
+public static class StdPipe
+{
+ public static void RouteToPipe(string pipeServer, string pipeName)
+ {
+ var pipeClient = new NamedPipeClientStream(pipeServer, pipeName, PipeDirection.InOut, PipeOptions.Asynchronous);
+ pipeClient.Connect();
+
+ var pipeReader = new BufferedStream(pipeClient);
+ var pipeWriter = new BufferedStream(pipeClient);
+
+ var stdin = new BufferedStream(Console.OpenStandardInput());
+ var stdout = new BufferedStream(Console.OpenStandardOutput());
+
+ var tasks = new Task<byte[]>[2]
+ {
+ ReadHeaderDelimitedAsync(pipeReader),
+ ReadHeaderDelimitedAsync(stdin)
+ };
+
+ while (true)
+ {
+ var doneIdx = Task.WaitAny(tasks);
+
+ var bytesRead = tasks[doneIdx].Result;
+ if (doneIdx == 0)
+ {
+ // pipe in -> stdout
+ if (bytesRead.Length == 0)
+ {
+ // pipe was closed
+ break;
+ }
+
+ stdout.Write(bytesRead, 0, bytesRead.Length);
+ stdout.Flush();
+ tasks[doneIdx] = ReadHeaderDelimitedAsync(pipeReader);
+ }
+ else
+ {
+ // stdin -> pipe out
+ pipeWriter.Write(bytesRead, 0, bytesRead.Length);
+ pipeWriter.Flush();
+ tasks[doneIdx] = ReadHeaderDelimitedAsync(stdin);
+ }
+ }
+ }
+
+ private static async Task<byte[]> ReadHeaderDelimitedAsync(Stream stream)
+ {
+ // Assigning new tasks with this function blocks the thread
+ // unless this is awaited first.
+ await Task.Yield();
+
+ var idx = 0;
+ var header = new byte[64];
+ int b = 0;
+ do
+ {
+ var bytesRead = await stream.ReadAsync(header, idx, 1);
+ if (bytesRead == 0)
+ continue;
+ b = header[idx++];
+ } while (b != '\r');
+
+ var colonPos = Array.IndexOf(header, (byte)':');
+ if (colonPos == -1)
+ {
+ return new byte[0];
+ }
+
+ var headerName = new byte[colonPos];
+ Array.Copy(header, headerName, colonPos);
+ var headerContent = new byte[idx - colonPos - 1];
+ Array.Copy(header, colonPos + 2, headerContent, 0, headerContent.Length - 2);
+
+ if (Encoding.ASCII.GetString(headerName) != "Content-Length")
+ {
+ return new byte[0];
+ }
+ if (headerContent.Length > 20)
+ {
+ return new byte[0];
+ }
+ int contentLength;
+ try
+ {
+ contentLength = int.Parse(Encoding.ASCII.GetString(headerContent));
+ }
+ catch (Exception)
+ {
+ return new byte[0];
+ }
+
+ var buffer = new byte[contentLength + idx + 3];
+ var c = 0;
+ for (var i = 0; i < idx; i++)
+ {
+ buffer[c++] = header[i];
+ }
+
+ // LF, CRLF
+ var bytesToRead = contentLength + 3;
+ while (bytesToRead > 0)
+ {
+ var bytesRead = await stream.ReadAsync(buffer, c, bytesToRead);
+ bytesToRead -= bytesRead;
+ c += bytesRead;
+ }
+
+ return buffer;
+ }
+}
+"@
+
+Add-Type -TypeDefinition $Source -Language CSharp
+
+try {
+ [StdPipe]::RouteToPipe($ServerName, $PipeName)
+} catch [System.AggregateException] {
+ Write-Error $error[0].exception.innerexception
+ throw $error[0].exception.innerexception
+}