From bb374f3817239e986edb663b522aa202f92280ba Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Wed, 17 Feb 2021 12:10:35 +0100
Subject: [lspc] imprve mapping between languages and language servers

Previously we managed running language servers by language but this
is not practical since one language server can serve multiple languages.
Clangd for example can deal with cpp and c code which frequently are
used together in the same code base.
Therefore we now manage running language servers by name and map
syntax to language server names and to LSP languageIds as well.
---
 init.lua | 42 +++++++++++++++++++++++++++++++++---------
 1 file changed, 33 insertions(+), 9 deletions(-)

(limited to 'init.lua')

diff --git a/init.lua b/init.lua
index d916075..cd35072 100644
--- a/init.lua
+++ b/init.lua
@@ -58,6 +58,7 @@ end
 
 -- state of our language server client
 lspc = {
+  -- mapping language server names to their state tables
   running = {},
   name = 'vis-lspc',
   version = '0.1.0',
@@ -77,12 +78,29 @@ if os.execute('type fzf >/dev/null 2>/dev/null') then
   lspc.menu_cmd = 'fzf'
 end
 
+-- mapping function between vis lexer names and LSP languageIds
+local function syntax_to_languageId(syntax)
+  if syntax == 'ansi_c' then
+    return 'c'
+  end
+  return syntax
+end
+
 -- clangd language server configuration
 local clangd = {name = 'clangd', cmd = 'clangd'}
 
 -- map of known language servers per syntax
 lspc.ls_map = {cpp = clangd, ansi_c = clangd}
 
+-- return the name of the language server for this syntax
+local function get_ls_name_for_syntax(syntax)
+  local ls_def = lspc.ls_map[syntax]
+  if not ls_def then
+    return nil, 'No language server available for ' .. syntax
+  end
+  return ls_def.name
+end
+
 -- Document position code
 -- https://microsoft.github.io/language-server-protocol/specifications/specification-current/#textDocumentPositionParams
 
@@ -409,9 +427,9 @@ local function ls_handle_method_response(ls, method_response)
     ls.fd:close()
 
     -- remove the ls from lspc.running
-    for syntax, rls in pairs(lspc.running) do
+    for ls_name, rls in pairs(lspc.running) do
       if ls == rls then
-        lspc.running[syntax] = nil
+        lspc.running[ls_name] = nil
         break
       end
     end
@@ -489,6 +507,12 @@ end
 
 -- check if a language server is running and initialized
 local function lspc_get_usable_ls(syntax)
+  local ls_name, err = get_ls_name_for_syntax(syntax)
+  if err then
+    return nil, err
+  end
+
+  local ls = lspc.running[ls_name]
   if not ls then
     return nil, 'Error: No language server running for ' .. syntax
   end
@@ -521,7 +545,7 @@ local function lspc_open(ls, win, file)
   local params = {
     textDocument = {
       uri = 'file://' .. file.path,
-      languageId = win.syntax,
+      languageId = syntax_to_languageId(win.syntax),
       version = 0,
       text = file:content(0, file.size),
     },
@@ -560,15 +584,15 @@ local function ls_shutdown_server(ls)
 end
 
 local function ls_start_server(syntax)
-  if lspc.running[syntax] then
-    return nil, 'Error: Already a language server running for ' .. syntax
-  end
-
   local ls_conf = lspc.ls_map[syntax]
   if not ls_conf then
     return nil, 'Error: No language server available for ' .. syntax
   end
 
+  if lspc.running[ls_conf.name] then
+    return nil, 'Error: Already a language server running for ' .. syntax
+  end
+
   local ls = {
     name = ls_conf.name,
     initialized = false,
@@ -580,7 +604,7 @@ local function ls_start_server(syntax)
 
   ls.fd = vis:communicate(ls_conf.name, ls_conf.cmd)
 
-  lspc.running[syntax] = ls
+  lspc.running[ls_conf.name] = ls
 
   -- register the response handler
   vis.events.subscribe(vis.events.PROCESS_RESPONSE, function(name, msg, event)
@@ -595,7 +619,7 @@ local function ls_start_server(syntax)
         vis:info('language server received signal: ' .. msg)
       end
 
-      lspc.running[syntax] = nil
+      lspc.running[ls.name] = nil
       return
     end
 
-- 
cgit v1.2.3