Server shutdown in case the client process has exited unexpectedly. (#64

)

Monitor the client process ID, received in the initialize request and shutdown
the server in case the client process is found to be dead. This fixes the
remaining nimlangserver processes after an IDE crash, or in case of broken IDE
and/or plugin not sending the proper shutdown and exit commands to the server.

nimlangserver.nim

@@ -2,7 +2,8 @@ import macros, strformat, faststreams/async_backend,
   faststreams/asynctools_adapters, faststreams/inputs, faststreams/outputs,
   json_rpc/streamconnection, os, sugar, sequtils, hashes, osproc,
   suggestapi, protocol/enums, protocol/types, with, tables, strutils, sets,
-  ./utils, ./pipes, chronicles, std/re, uri, "$nim/compiler/pathutils"
+  ./utils, ./pipes, chronicles, std/re, uri, "$nim/compiler/pathutils",
+  procmonitor
 
 const
   RESTART_COMMAND = "nimlangserver.restart"
@@ -159,6 +160,10 @@ proc getCharacter(ls: LanguageServer, uri: string, line: int, character: int): i
 proc initialize(ls: LanguageServer, params: InitializeParams):
     Future[InitializeResult] {.async.} =
   debug "Initialize received..."
+  if params.processId.isSome:
+    let pid = params.processId.get
+    if pid.kind == JInt:
+      hookProcMonitor(int(pid.num))
   ls.initializeParams = params
   result = InitializeResult(
     capabilities: ServerCapabilities(

procmonitor.nim

@@ -0,0 +1,34 @@
+# Monitor a client process and shutdown the current process, if the client
+# process is found to be dead
+
+import os
+
+when defined(posix):
+  import posix_utils
+  import posix
+
+when defined(windows):
+  import winlean
+
+when defined(posix):
+  proc monitorClientProcessIdThreadProc(pid: int) {.thread.} =
+    while true:
+      sleep(1000)
+      try:
+        sendSignal(Pid(pid), 0)
+      except:
+        discard kill(Pid(getCurrentProcessId()), cint(SIGTERM))
+
+when defined(windows):
+  proc monitorClientProcessIdThreadProc(pid: int) {.thread.} =
+    var process = openProcess(SYNCHRONIZE, 0, DWORD(pid))
+    if process != 0:
+      discard waitForSingleObject(process, INFINITE)
+      discard closeHandle(process)
+    quit(0)
+
+var tid: Thread[int]
+
+proc hookProcMonitor*(pid: int) =
+  when defined(posix) or defined(windows):
+    createThread(tid, monitorClientProcessIdThreadProc, pid)