Prefer native lsp api when in vim. (#1362)

* add g:lsp_experimental_native_lsp flag to enable native vim lsp client

* send request and correctly call on_notification

* add support for native client in lsp#client#send_notification

* Add native lsp client support for lsp#client#send_response

* add native notification support

* add support for native stop job

* handle error response for document_formatting.vim and code_action.vim

* add missing return for code action

* fix indent

* undo code action error

* check for a:response to be of type dict as stderr will send string

* use out_cb and err_cb instead of channel callback

* bump has_native_client version check to 8.2.4780 which fixes LSP parsing messages when partial data is received

* rename g:lsp_experimental_native_lsp to g:lsp_use_native_client

* fix s:native_err_cb

* pass env

* disable lsp_use_native_client

* add lsp#utils#has_native_lsp_client()

* clean up log

* handle requests from server

* fix lint issues

* update docs

autoload/lsp.vim

@@ -449,7 +449,7 @@ function! s:ensure_start(buf, server_name, cb) abort
     let l:server_info = l:server['server_info']
     if l:server['lsp_id'] > 0
         let l:msg = s:new_rpc_success('server already started', { 'server_name': a:server_name })
-        call lsp#log(l:msg)
+        call lsp#log_verbose(l:msg)
         call a:cb(l:msg)
         return
     endif
@@ -647,7 +647,7 @@ function! s:ensure_init(buf, server_name, cb) abort
 
     if has_key(l:server, 'init_result')
         let l:msg = s:new_rpc_success('lsp server already initialized', { 'server_name': a:server_name, 'init_result': l:server['init_result'] })
-        call lsp#log(l:msg)
+        call lsp#log_verbose(l:msg)
         call a:cb(l:msg)
         return
     endif
@@ -721,7 +721,7 @@ function! s:ensure_conf(buf, server_name, cb) abort
             \ })
     endif
     let l:msg = s:new_rpc_success('configuration sent', { 'server_name': a:server_name })
-    call lsp#log(l:msg)
+    call lsp#log_verbose(l:msg)
     call a:cb(l:msg)
 endfunction
 
@@ -768,7 +768,7 @@ function! s:ensure_changed(buf, server_name, cb) abort
 
     if l:buffer_info['changed_tick'] == l:changed_tick
         let l:msg = s:new_rpc_success('not dirty', { 'server_name': a:server_name, 'path': l:path })
-        call lsp#log(l:msg)
+        call lsp#log_verbose(l:msg)
         call a:cb(l:msg)
         return
     endif
@@ -805,7 +805,7 @@ function! s:ensure_open(buf, server_name, cb) abort
 
     if has_key(l:buffers, l:path)
         let l:msg = s:new_rpc_success('already opened', { 'server_name': a:server_name, 'path': l:path })
-        call lsp#log(l:msg)
+        call lsp#log_verbose(l:msg)
         call a:cb(l:msg)
         return
     endif

autoload/lsp/client.vim

@@ -3,6 +3,9 @@ set cpoptions&vim
 
 let s:clients = {} " { client_id: ctx }
 
+" Vars used by native lsp
+let s:jobidseq = 0
+
 function! s:create_context(client_id, opts) abort
     if a:client_id <= 0
         return {}
@@ -212,9 +215,7 @@ let s:send_type_notification = 2
 let s:send_type_response = 3
 function! s:lsp_send(id, opts, type) abort " opts = { id?, method?, result?, params?, on_notification }
     let l:ctx = get(s:clients, a:id, {})
-    if empty(l:ctx)
-        return -1
-    endif
+    if empty(l:ctx) | return -1 | endif
 
     let l:request = { 'jsonrpc': '2.0' }
 
@@ -281,26 +282,156 @@ function! s:is_server_instantiated_notification(notification) abort
     return !has_key(a:notification, 'request')
 endfunction
 
+function! s:native_out_cb(cbctx, channel, response) abort
+    if !has_key(a:cbctx, 'ctx') | return | endif
+    let l:ctx = a:cbctx['ctx']
+    if has_key(a:response, 'method') && has_key(a:response, 'id')
+        " it is a request from a server
+        let l:request = a:response
+        if has_key(l:ctx['opts'], 'on_request')
+            call l:ctx['opts']['on_request'](l:ctx['id'], l:request)
+        endif
+    elseif !has_key(a:response, 'id') && has_key(l:ctx['opts'], 'on_notification')
+        " it is a notification
+        let l:on_notification_data = { 'response': a:response }
+        try
+            call l:ctx['opts']['on_notification'](l:ctx['id'], l:on_notification_data, 'on_notification')
+        catch
+            call lsp#log('s:native_notification_callback on_notification() error', v:exception, v:throwpoint)
+        endtry
+    endif
+endfunction
+
+function! s:native_err_cb(cbctx, channel, response) abort
+    if !has_key(a:cbctx, 'ctx') | return | endif
+    let l:ctx = a:cbctx['ctx']
+    if has_key(l:ctx['opts'], 'on_stderr')
+        try
+            call l:ctx['opts']['on_stderr'](l:ctx['id'], a:response, 'stderr')
+        catch
+            call lsp#log('s:on_stderr exception', v:exception, v:throwpoint)
+            echom v:exception
+        endtry
+    endif
+endfunction
+
 " public apis {{{
 
 function! lsp#client#start(opts) abort
+    if g:lsp_use_native_client && lsp#utils#has_native_lsp_client()
+        if has_key(a:opts, 'cmd')
+            let l:cbctx = {}
+            let l:jobopt = { 'in_mode': 'lsp', 'out_mode': 'lsp', 'noblock': 1,
+                \ 'out_cb': function('s:native_out_cb', [l:cbctx]),
+                \ 'err_cb': function('s:native_err_cb', [l:cbctx]),
+                \ }
+            if has_key(a:opts, 'cwd') | let l:jobopt['cwd'] = a:opts['cwd'] | endif
+            if has_key(a:opts, 'env') | let l:jobopt['env'] = a:opts['env'] | endif
+            let s:jobidseq += 1
+            let l:jobid = s:jobidseq " jobid == clientid
+            call lsp#log_verbose('using native lsp client')
+            let l:job = job_start(a:opts['cmd'], l:jobopt)
+            if job_status(l:job) !=? 'run' | return -1 | endif
+            let l:ctx = s:create_context(l:jobid, a:opts)
+            let l:ctx['id'] = l:jobid
+            let l:ctx['job'] = l:job
+            let l:ctx['channel'] = job_getchannel(l:job)
+            let l:cbctx['ctx'] = l:ctx
+            return l:jobid
+        elseif has_key(a:opts, 'tcp')
+            " add support for tcp
+            call lsp#log('tcp not supported when using native lsp client')
+            return -1
+        endif
+    endif
     return s:lsp_start(a:opts)
 endfunction
 
 function! lsp#client#stop(client_id) abort
+    if g:lsp_use_native_client && lsp#utils#has_native_lsp_client()
+       let l:ctx = get(s:clients, a:client_id, {})
+       if empty(l:ctx) | return | endif
+       call job_stop(l:ctx['job'])
+    else
         return s:lsp_stop(a:client_id)
+    endif
 endfunction
 
 function! lsp#client#send_request(client_id, opts) abort
+    if g:lsp_use_native_client && lsp#utils#has_native_lsp_client()
+        let l:ctx = get(s:clients, a:client_id, {})
+        if empty(l:ctx) | return -1 | endif
+        let l:request = {}
+        " id shouldn't be passed to request as vim will overwrite it. refer to :h language-server-protocol
+        if has_key(a:opts, 'method') | let l:request['method'] = a:opts['method'] | endif
+        if has_key(a:opts, 'params') | let l:request['params'] = a:opts['params'] | endif
+
+        call ch_sendexpr(l:ctx['channel'], l:request, { 'callback': function('s:on_response_native', [l:ctx, l:request]) })
+        let l:ctx['requests'][l:request['id']] = l:request
+        if has_key(a:opts, 'on_notification')
+            let l:ctx['on_notifications'][l:request['id']] = a:opts['on_notification']
+        endif
+        let l:ctx['request_sequence'] = l:request['id']
+        return l:request['id']
+    else
         return s:lsp_send(a:client_id, a:opts, s:send_type_request)
+    endif
+endfunction
+
+function! s:on_response_native(ctx, request, channel, response) abort
+    " request -> response
+    let l:on_notification_data = { 'response': a:response, 'request': a:request }
+    if has_key(a:ctx['opts'], 'on_notification')
+        " call client's on_notification first
+        try
+            call a:ctx['opts']['on_notification'](a:ctx['id'], l:on_notification_data, 'on_notification')
+        catch
+            call lsp#log('s:on_response_native client option on_notification() error', v:exception, v:throwpoint)
+        endtry
+    endif
+    if has_key(a:ctx['on_notifications'], a:request['id'])
+        " call lsp#client#send({ 'on_notification' }) second
+        try
+            call a:ctx['on_notifications'][a:request['id']](a:ctx['id'], l:on_notification_data, 'on_notification')
+        catch
+            call lsp#log('s:on_response_native client request on_notification() error', v:exception, v:throwpoint, a:request, a:response)
+        endtry
+        unlet a:ctx['on_notifications'][a:response['id']]
+        if has_key(a:ctx['requests'], a:response['id'])
+            unlet a:ctx['requests'][a:response['id']]
+        else
+            call lsp#log('cannot find the request corresponding to response: ', a:response)
+        endif
+    endif
 endfunction
 
 function! lsp#client#send_notification(client_id, opts) abort
+    if g:lsp_use_native_client && lsp#utils#has_native_lsp_client()
+        let l:ctx = get(s:clients, a:client_id, {})
+        if empty(l:ctx) | return -1 | endif
+        let l:request = {}
+        if has_key(a:opts, 'method') | let l:request['method'] = a:opts['method'] | endif
+        if has_key(a:opts, 'params') | let l:request['params'] = a:opts['params'] | endif
+        call ch_sendexpr(l:ctx['channel'], l:request)
+        return 0
+    else
         return s:lsp_send(a:client_id, a:opts, s:send_type_notification)
+    endif
 endfunction
 
 function! lsp#client#send_response(client_id, opts) abort
+    if g:lsp_use_native_client && lsp#utils#has_native_lsp_client()
+        let l:ctx = get(s:clients, a:client_id, {})
+        if empty(l:ctx) | return -1 | endif
+        let l:request = {}
+        if has_key(a:opts, 'id') | let l:request['id'] = a:opts['id'] | endif
+        if has_key(a:opts, 'result') | let l:request['result'] = a:opts['result'] | endif
+        if has_key(a:opts, 'error') | let l:request['error'] = a:opts['error'] | endif
+        call ch_sendexpr(l:ctx['channel'], l:request)
+        return 0
+    else
         return s:lsp_send(a:client_id, a:opts, s:send_type_response)
+    endif
 endfunction
 
 function! lsp#client#get_last_request_id(client_id) abort

autoload/lsp/utils.vim

@@ -3,6 +3,11 @@ function! lsp#utils#has_lua() abort
     return s:has_lua
 endfunction
 
+let s:has_native_lsp_client = !has('nvim') && has('patch-8.2.4780')
+function! lsp#utils#has_native_lsp_client() abort
+    return s:has_native_lsp_client
+endfunction
+
 let s:has_virtual_text = exists('*nvim_buf_set_virtual_text') && exists('*nvim_create_namespace')
 function! lsp#utils#_has_nvim_virtual_text() abort
     return s:has_virtual_text

doc/vim-lsp.txt

@@ -14,6 +14,7 @@ CONTENTS                                                  *vim-lsp-contents*
       Health Check                          |vim-lsp-healthcheck|
     Options                               |vim-lsp-options|
       g:lsp_auto_enable                     |g:lsp_auto_enable|
+      g:lsp_use_native_client               |g:lsp_use_native_client|
       g:lsp_preview_keep_focus              |g:lsp_preview_keep_focus|
       g:lsp_preview_float                   |g:lsp_preview_float|
       g:lsp_preview_autoclose               |g:lsp_preview_autoclose|
@@ -207,6 +208,9 @@ http://downloads.sourceforge.net/luabinaries/lua-5.3.2_Win32_dllw4_lib.zip
 64bit:
 http://downloads.sourceforge.net/luabinaries/lua-5.3.2_Win64_dllw4_lib.zip
 
+If you are using vim set `let g:lsp_use_native_client = 1` and make sure you
+are running vim 8.2.4780+.
+
 Set |g:lsp_semantic_enabled| to 0.
 
 Set |g:lsp_format_sync_timeout| to a reasonable value such as `1000`.
@@ -297,6 +301,18 @@ g:lsp_auto_enable                                       *g:lsp_auto_enable*
 	let g:lsp_auto_enable = 1
 	let g:lsp_auto_enable = 0
 
+g:lsp_use_native_client                             *g:lsp_use_native_client*
+    Type: |Number|
+    Default: `0`
+
+    Enable native lsp client support for vim 8.2.4780+. No impact for neovim.
+    TCP language servers are not supported and should be set to 0 if one is
+    used.
+
+    Example: >
+	let g:lsp_use_native_client = 1
+	let g:lsp_use_native_client = 0
+
 g:lsp_preview_keep_focus                         *g:lsp_preview_keep_focus*
     Type: |Number|
     Default: `1`

plugin/lsp.vim

@@ -4,6 +4,7 @@ endif
 let g:lsp_loaded = 1
 
 let g:lsp_use_lua = get(g:, 'lsp_use_lua', has('nvim-0.4.0') || (has('lua') && has('patch-8.2.0775')))
+let g:lsp_use_native_client = get(g:, 'lsp_use_native_client', 0)
 let g:lsp_auto_enable = get(g:, 'lsp_auto_enable', 1)
 let g:lsp_async_completion = get(g:, 'lsp_async_completion', 0)
 let g:lsp_log_file = get(g:, 'lsp_log_file', '')