Merge branch 'tcp'

Author: fwcd

EDITORS.md

@@ -42,4 +42,6 @@ Add the following to your coc-settings.json file:
 Note that you may need to substitute `kotlin-language-server` with `kotlin-language-server.bat` on Windows.
 
 ## Other Editors
-Install a [Language Server Protocol client](https://microsoft.github.io/language-server-protocol/implementors/tools/) for your tool. Then invoke the language server executable in a client-specific way. The server uses `stdio` to send and receive `JSON-RPC` messages.
+Install a [Language Server Protocol client](https://microsoft.github.io/language-server-protocol/implementors/tools/) for your tool. Then invoke the language server executable in a client-specific way.
+
+The server uses `stdio` by default to send and receive `JSON-RPC` messages, but can be launched with the argument `--tcpPort=port` for TCP support.

server/build.gradle

@@ -52,6 +52,7 @@ dependencies {
     implementation 'org.jetbrains:fernflower:1.0'
     implementation 'com.pinterest.ktlint:ktlint-core:0.34.2'
     implementation 'com.pinterest.ktlint:ktlint-ruleset-standard:0.34.2'
+    implementation 'com.beust:jcommander:1.78'
 
     // Re-add to depend on Kotlin plugin classes directly. Note that
     // this plugin uses the normal imports (com.intellij.*)

server/src/main/kotlin/org/javacs/kt/Main.kt

@@ -1,19 +1,28 @@
 package org.javacs.kt
 
+import com.beust.jcommander.JCommander
+import com.beust.jcommander.Parameter
 import java.util.concurrent.Executors
 import org.eclipse.lsp4j.launch.LSPLauncher
 import org.eclipse.lsp4j.ConfigurationParams
 import org.eclipse.lsp4j.ConfigurationItem
 import org.javacs.kt.util.ExitingInputStream
 
-fun main(args: Array<String>) {
+class Args {
+    @Parameter(names = ["--tcpPort", "-p"])
+    var tcpPort: Int? = null
+}
+
+fun main(argv: Array<String>) {
     // Redirect java.util.logging calls (e.g. from LSP4J)
     LOG.connectJULFrontend()
 
+    val args = Args().also { JCommander.newBuilder().addObject(it).build().parse(*argv) }
+    val (inStream, outStream) = args.tcpPort?.let { tcpConnectToClient(it) } ?: Pair(System.`in`, System.out)
+
     val server = KotlinLanguageServer()
-    val input = ExitingInputStream(System.`in`)
     val threads = Executors.newSingleThreadExecutor { Thread(it, "client") }
-    val launcher = LSPLauncher.createServerLauncher(server, input, System.out, threads, { it })
+    val launcher = LSPLauncher.createServerLauncher(server, ExitingInputStream(inStream), outStream, threads, { it })
 
     server.connect(launcher.remoteProxy)
     launcher.startListening()

server/src/main/kotlin/org/javacs/kt/TcpStream.kt

@@ -0,0 +1,12 @@
+package org.javacs.kt
+
+import java.io.InputStream
+import java.io.OutputStream
+import java.net.ServerSocket
+
+/**
+ * Starts a TCP server socket. Blocks until the first
+ * client has connected, then returns a pair of IO streams.
+ */
+fun tcpConnectToClient(port: Int): Pair<InputStream, OutputStream> =
+    ServerSocket(port).accept().let { Pair(it.inputStream, it.outputStream) }