Fix the Pipe handling on Windows to be correct

This actually addresses the real issue that was ignored earlier about
pipes on Windows.  The FileHandle cannot provide a non-owning file
descriptor (the returned file descriptor would need to be explicitly
`_close`'d by the receiver).  Foundation now vends a `_handle` accessor
to the OS primitive handle.  Use this to create the dispatch loop for
messaging.  We now create the JSONRPCConnection from handles on Windows
which actually should help enable running some of the tests on Windows
as well.

Author: compnerd

Sources/LSPTestSupport/TestJSONRPCConnection.swift

@@ -29,14 +29,14 @@ public final class TestJSONRPCConnection {
   public init() {
     clientConnection = JSONRPCConnection(
       protocol: testMessageRegistry,
-      inFD: serverToClient.fileHandleForReading.fileDescriptor,
-      outFD: clientToServer.fileHandleForWriting.fileDescriptor
+      inFD: serverToClient.fileHandleForReading,
+      outFD: clientToServer.fileHandleForWriting
     )
 
     serverConnection = JSONRPCConnection(
       protocol: testMessageRegistry,
-      inFD: clientToServer.fileHandleForReading.fileDescriptor,
-      outFD: serverToClient.fileHandleForWriting.fileDescriptor
+      inFD: clientToServer.fileHandleForReading,
+      outFD: serverToClient.fileHandleForWriting
     )
 
     client = TestClient(server: clientConnection)

Sources/LanguageServerProtocolJSONRPC/JSONRPCConnection.swift

@@ -11,15 +11,12 @@
 //===----------------------------------------------------------------------===//
 
 #if canImport(CDispatch)
-import CDispatch
+import struct CDispatch.dispatch_fd_t
 #endif
 import Dispatch
 import Foundation
 import LanguageServerProtocol
 import LSPLogging
-#if os(Windows)
-import ucrt
-#endif
 
 /// A connection between a message handler (e.g. language server) in the same process as the connection object and a remote message handler (e.g. language client) that may run in another process using JSON RPC messages sent over a pair of in/out file descriptors.
 ///
@@ -62,8 +59,8 @@ public final class JSONRPCConnection {
 
   public init(
     protocol messageRegistry: MessageRegistry,
-    inFD: Int32,
-    outFD: Int32,
+    inFD: FileHandle,
+    outFD: FileHandle,
     syncRequests: Bool = false)
   {
     state = .created
@@ -72,26 +69,28 @@ public final class JSONRPCConnection {
 
     let ioGroup = DispatchGroup()
 
-    ioGroup.enter()
 #if os(Windows)
-    let inDesc: dispatch_fd_t = dispatch_fd_t(_get_osfhandle(inFD))
+    let rawInFD = dispatch_fd_t(bitPattern: inFD._handle)
 #else
-    let inDesc: Int32 = Int32(inFD)
+    let rawInFD = inFD.fileDescriptor
 #endif
-    receiveIO = DispatchIO(type: .stream, fileDescriptor: inDesc, queue: queue) { (error: Int32) in
+
+    ioGroup.enter()
+    receiveIO = DispatchIO(type: .stream, fileDescriptor: rawInFD, queue: queue) { (error: Int32) in
       if error != 0 {
         log("IO error \(error)", level: .error)
       }
       ioGroup.leave()
     }
 
-    ioGroup.enter()
 #if os(Windows)
-    let outDesc: dispatch_fd_t = dispatch_fd_t(_get_osfhandle(outFD))
+    let rawOutFD = dispatch_fd_t(bitPattern: outFD._handle)
 #else
-    let outDesc: Int32 = Int32(outFD)
+    let rawOutFD = outFD.fileDescriptor
 #endif
-    sendIO = DispatchIO(type: .stream, fileDescriptor: outDesc, queue: sendQueue) { (error: Int32) in
+
+    ioGroup.enter()
+    sendIO = DispatchIO(type: .stream, fileDescriptor: rawOutFD, queue: sendQueue) { (error: Int32) in
       if error != 0 {
         log("IO error \(error)", level: .error)
       }

Sources/SKCore/BuildServerBuildSystem.swift

@@ -250,8 +250,8 @@ private func makeJSONRPCBuildServer(client: MessageHandler, serverPath: Absolute
 
   let connection = JSONRPCConnection(
     protocol: BuildServerProtocol.bspRegistry,
-    inFD: serverToClient.fileHandleForReading.fileDescriptor,
-    outFD: clientToServer.fileHandleForWriting.fileDescriptor
+    inFD: serverToClient.fileHandleForReading,
+    outFD: clientToServer.fileHandleForWriting
   )
 
   connection.start(receiveHandler: client) {

Sources/SourceKitLSP/Clang/ClangLanguageServer.swift

@@ -293,8 +293,8 @@ func makeJSONRPCClangServer(
 
   let connection = JSONRPCConnection(
     protocol: MessageRegistry.lspProtocol,
-    inFD: clangdToUs.fileHandleForReading.fileDescriptor,
-    outFD: usToClangd.fileHandleForWriting.fileDescriptor
+    inFD: clangdToUs.fileHandleForReading,
+    outFD: usToClangd.fileHandleForWriting
   )
 
   let connectionToClient = LocalConnection()

Sources/sourcekit-lsp/main.swift

@@ -161,8 +161,8 @@ struct Main: ParsableCommand {
 
     let clientConnection = JSONRPCConnection(
       protocol: MessageRegistry.lspProtocol,
-      inFD: fileno(stdin),
-      outFD: realStdout,
+      inFD: FileHandle(fileDescriptor: fileno(stdin), closeOnDealloc: false),
+      outFD: FileHandle.standardInput,
       syncRequests: syncRequests
     )