Improve handling of key mapping

autoload/lsc/config.vim

@@ -51,6 +51,8 @@ function! lsc#config#mapKeys() abort
     return
   endif
 
+  let b:lsc_save = {}
+  let b:lsc_maps = []
   for command in [
       \ 'GoToDefinition',
       \ 'GoToDefinitionSplit',
@@ -69,24 +71,50 @@ function! lsc#config#mapKeys() abort
       continue
     endif
     for m in type(lhs) == type([]) ? lhs : [lhs]
+      call add(b:lsc_maps, m)
       execute 'nnoremap <buffer>'.m.' :LSClient'.command.'<CR>'
     endfor
   endfor
   if has_key(l:maps, 'Completion') &&
       \ type(l:maps['Completion']) == type('') &&
       \ len(l:maps['Completion']) > 0
+    let b:lsc_save[l:maps['Completion']] = getbufvar('', l:maps['Completion'])
     execute 'setlocal '.l:maps['Completion'].'=lsc#complete#complete'
   endif
   if has_key(l:maps, 'ShowHover')
     let l:show_hover = l:maps['ShowHover']
     if type(l:show_hover) == type(v:true) || type(l:show_hover) == type(0)
       if l:show_hover
+        let b:lsc_save.keywordprg = &l:keywordprg
         setlocal keywordprg=:LSClientShowHover
       endif
     endif
   endif
 endfunction
 
+function! lsc#config#unmapKeys() abort
+  if exists('b:lsc_save')
+    for opt in keys(b:lsc_save)
+      execute 'setlocal '.opt.'='.b:lsc_save[opt]
+    endfor
+    unlet b:lsc_save
+  endif
+
+  if exists('b:lsc_maps')
+    for m in b:lsc_maps
+      silent! execute 'nunmap <buffer>'.m
+    endfor
+    unlet b:lsc_maps
+  endif
+endfunction
+
+" Unmap buffer-local keys if the associated language server is not running
+function! lsc#config#checkKeys() abort
+  if lsc#server#status(&filetype) !=# 'running'
+    call lsc#config#unmapKeys()
+  endif
+endfunction
+
 " Wraps [Callback] with a function that will first translate a result through a
 " user provided translation.
 function! lsc#config#responseHook(server, method, Callback) abort

autoload/lsc/file.vim

@@ -22,7 +22,6 @@ endfunction
 " Run language servers for this filetype if they aren't already running and
 " flush file changes.
 function! lsc#file#onOpen() abort
-  call lsc#config#mapKeys()
   if &modifiable && expand('%') !~# '\vfugitive:///'
     call lsc#server#start(&filetype)
     call s:FlushChanges(lsc#file#fullPath(), &filetype)

autoload/lsc/server.vim

@@ -87,6 +87,11 @@ function! s:Kill(server, status, OnExit) abort
       call a:server._channel.notify('exit', v:null)
     endif
     if a:OnExit != v:null | call a:OnExit() | endif
+
+    " Unmap keys if the language server is used in the current buffer
+    if index(a:server.filetypes, &filetype) >= 0
+      call lsc#config#unmapKeys()
+    endif
   endfunction
   return a:server.request('shutdown', v:null, funcref('Exit'))
 endfunction
@@ -119,6 +124,7 @@ endfunction
 function! s:Start(server) abort
   if has_key(a:server, '_channel')
     " Server is already running
+    call lsc#config#mapKeys()
     return
   endif
   let l:command = a:server.config.command
@@ -145,6 +151,7 @@ function! s:Start(server) abort
     for filetype in a:server.filetypes
       call lsc#file#trackAll(filetype)
     endfor
+    call lsc#config#mapKeys()
   endfunction
   if exists('g:lsc_trace_level') &&
       \ index(['off', 'messages', 'verbose'], g:lsc_trace_level) >= 0

plugin/lsc.vim

@@ -145,6 +145,7 @@ function! LSCEnsureCurrentWindowState() abort
   call lsc#diagnostics#updateLocationList(lsc#file#fullPath())
   call lsc#highlights#update()
   call lsc#cursor#onWinEnter()
+  call lsc#config#checkKeys()
 endfunction
 
 " Run `function` if LSC is enabled for the current filetype.
@@ -159,7 +160,6 @@ endfunction
 
 function! s:OnOpen() abort
   if !has_key(g:lsc_servers_by_filetype, &filetype) | return | endif
-  call lsc#config#mapKeys()
   if !lsc#server#filetypeActive(&filetype) | return | endif
   call lsc#file#onOpen()
 endfunction