Refactor throttle messaging (#43)

* Refactor code to improve performance

Changed the status line function to just get a buffer variable for the
status line and delegate the update of this variable to the lsp_handlers

* Implemented a timer base update instead of autocmd

Using the libuv loop to schedule a timer base interval to update the
statusline. This will schedule the tasks to redraw the statusline every
100ms and if the statusline is different.

NOTE: There is an issue with the status text not updating that needs to
be fixed

* Fixed timer functionality

Now the timer function work but the last message is still displayed on
the screen.

* Cleanup unused variables

* Fix missing status update

This will redraw one more time after the last LSP update

* Fix return value from global to buffer

Author: joshuachp

doc/lsp-status.txt

@@ -194,7 +194,8 @@ update_current_function()               *lsp-status.update_current_function()*
 Module: lsp-status.clangd                              *lsp-status-api-clangd*
 
 setup()                                 *lsp-status.extensions.clangd.setup()*
-                Return the handler {LSP Method: handler} table for `clangd` 's `fileStatus` extension
+                Return the handler {LSP Method: handler} table for `clangd` 's
+                `fileStatus` extension
 
                 Return: ~
                     Table of extension method handlers, to be added to your
@@ -205,7 +206,8 @@ setup()                                 *lsp-status.extensions.clangd.setup()*
 Module: lsp-status.pyls_ms                            *lsp-status-api-pyls_ms*
 
 setup()                                *lsp-status.extensions.pyls_ms.setup()*
-                Return the handler {LSP Method: handler} table for `MPLS` 's progress and statusbar message extensions
+                Return the handler {LSP Method: handler} table for `MPLS` 's
+                progress and statusbar message extensions
 
                 Return: ~
                     Table of extension method handlers, to be added to your

lua/lsp-status.lua

@@ -1,4 +1,3 @@
-local _config = {}
 local default_config = {
   kind_labels = {},
   current_function = true,
@@ -12,8 +11,8 @@ local default_config = {
   status_symbol = ' 🇻',
   select_symbol = nil
 }
+local _config = vim.deepcopy(default_config)
 
-_config = vim.deepcopy(default_config)
 local messages = {}
 
 -- Diagnostics
@@ -23,6 +22,7 @@ local messages = {}
 local function diagnostics() -- luacheck: no unused
   error() -- Stub for docs
 end
+
 local diagnostics = require('lsp-status/diagnostics')
 
 -- Messaging
@@ -79,14 +79,6 @@ local function on_attach(client)
   -- Register the client for messages
   messaging.register_client(client.id, client.name)
 
-  -- Set up autocommands to refresh the statusline when information changes
-  vim.api.nvim_command('augroup lsp_aucmds')
-  vim.api.nvim_command('au! * <buffer>')
-  vim.api.nvim_command('au User LspDiagnosticsChanged redrawstatus!')
-  vim.api.nvim_command('au User LspMessageUpdate redrawstatus!')
-  vim.api.nvim_command('au User LspStatusUpdate redrawstatus!')
-  vim.api.nvim_command('augroup END')
-
   -- If the client is a documentSymbolProvider, set up an autocommand
   -- to update the containing symbol
   if _config.current_function and client.resolved_capabilities.document_symbol then
@@ -96,6 +88,8 @@ local function on_attach(client)
     )
     vim.api.nvim_command('augroup END')
   end
+
+  require('lsp-status/timer').register_timer()
 end
 
 config(_config)

lua/lsp-status/current_function.lua

@@ -21,7 +21,7 @@ local function current_function_callback(_, _, result, _, _)
     end)
 
   if not function_symbols or #function_symbols == 0 then
-    vim.api.nvim_command('doautocmd <nomodeline> User LspStatusUpdate')
+    vim.b.lsp_status_redraw = true
     return
   end
 
@@ -38,7 +38,7 @@ local function current_function_callback(_, _, result, _, _)
       end
 
       vim.b.lsp_current_function = fn_name
-      vim.api.nvim_command('doautocmd <nomodeline> User LspStatusUpdate')
+      vim.b.lsp_status_redraw = true
       return
     end
   end

lua/lsp-status/extensions/clangd.lua

@@ -16,7 +16,7 @@ local handlers = {
   ['textDocument/clangd.fileStatus'] = function(_, _, statusMessage, client_id)
     ensure_init(client_id)
     messages[client_id].status = { uri = statusMessage.uri, content = statusMessage.state }
-    vim.api.nvim_command('doautocmd <nomodeline> User LspMessageUpdate')
+    vim.b.lsp_status_redraw = true
   end,
 }
 

lua/lsp-status/extensions/pyls_ms.lua

@@ -1,4 +1,5 @@
 local util = require('lsp-status/util')
+local statusline = require('lsp-status/statusline')
 
 local messages = {}
 ---@private
@@ -15,7 +16,7 @@ local handlers =  {
   ['python/setStatusBarMessage'] = function(_, _, message, client_id)
     ensure_init(client_id)
     messages[client_id].static_message = { content = message[1] }
-    vim.api.nvim_command('doautocmd <nomodeline> User LspMessageUpdate')
+    vim.b.lsp_status_redraw = true
   end,
   ['python/beginProgress'] = function(_, _, _, client_id)
     ensure_init(client_id)
@@ -26,11 +27,11 @@ local handlers =  {
   ['python/reportProgress'] = function(_, _, message, client_id)
     messages[client_id].progress[1].spinner = messages[client_id].progress[1].spinner + 1
     messages[client_id].progress[1].title = message[1]
-    vim.api.nvim_command('doautocmd <nomodeline> User LspMessageUpdate')
+    vim.b.lsp_status_redraw = true
   end,
   ['python/endProgress'] = function(_, _, _, client_id)
     messages[client_id].progress[1] = nil
-    vim.api.nvim_command('doautocmd <nomodeline> User LspMessageUpdate')
+    vim.b.lsp_status_redraw = true
   end,
 }
 

lua/lsp-status/messaging.lua

@@ -43,7 +43,7 @@ local function progress_callback(_, _, msg, client_id)
     table.insert(messages[client_id], {content = val, show_once = true, shown = 0})
   end
 
-  vim.api.nvim_command('doautocmd <nomodeline> User LspMessageUpdate')
+  vim.b.lsp_status_redraw = true
 end
 
 -- Process messages
@@ -95,7 +95,9 @@ local function get_messages()
   return new_messages
 end
 
-local function register_progress() vim.lsp.handlers['$/progress'] = progress_callback end
+local function register_progress()
+  vim.lsp.handlers['$/progress'] = progress_callback
+end
 
 -- Client registration for messages
 local function register_client(id, name)

lua/lsp-status/statusline.lua

@@ -36,7 +36,7 @@ local function init(_, _config)
   _info = make_statusline_component('info')
 end
 
-local function statusline_lsp(bufnr)
+local function get_lsp_statusline(bufnr)
   bufnr = bufnr or 0
   if #vim.lsp.buf_get_clients(bufnr) == 0 then
     return ''
@@ -74,7 +74,7 @@ local function statusline_lsp(bufnr)
   for _, msg in ipairs(buf_messages) do
     local name = aliases[msg.name] or msg.name
     local client_name = '[' .. name .. ']'
-    local contents = ''
+    local contents
     if msg.progress then
       contents = msg.title
       if msg.message then
@@ -132,9 +132,15 @@ local function get_component_functions()
   }
 end
 
+-- Status line component for nvim-lsp
+local function lsp_status()
+  return vim.b.lsp_status_statusline or ''
+end
+
 local M = {
   _init = init,
-  status = statusline_lsp,
+  status = lsp_status,
+  get_lsp_statusline = get_lsp_statusline,
   _get_component_functions = get_component_functions
 }
 

lua/lsp-status/timer.lua

@@ -0,0 +1,55 @@
+--- Timer instance
+local timer = nil
+--- This flag is used to redraw one more time after the las LSP update.
+-- NOTE: This is achieved by setting the redraw_flag to true if
+-- vim.b.lsp_status_redraw is true and there has been an update. Next time if
+-- vim.b.lsp_status_redraw is false (no update) it will still redraw the
+-- statusline and this flag will be set to false.
+local redraw_flag = false
+
+--- Timer callback function
+-- NOTE: This function uses get_lsp_statusline so that needs nvim api functions
+-- so it should call in the vim.schedule_wrap()
+local function timer_callback()
+  -- Check if need to redraw
+  local update_flag = vim.b.lsp_status_redraw
+  if update_flag or redraw_flag then
+    vim.b.lsp_status_redraw = false
+    -- Schedule the command when it's safe to call it
+    local new_state = require('lsp-status/statusline').get_lsp_statusline()
+    if new_state ~= vim.b.lsp_status_statusline then
+      vim.b.lsp_status_statusline = new_state
+      vim.api.nvim_command('redrawstatus!')
+      -- If this was an lsp update (update_flag is true) redraw also next time
+      -- by setting redraw_flag
+      redraw_flag = update_flag
+    end
+  end
+end
+
+--- Function to register a timer to update statusline
+-- This function is called on attach of a LSP Server and will pull updates for
+-- status line on a specific every interval of time. It will also schedule the
+-- redraw of the status line on the main loop. This will reduce the lag for
+-- servers that constantly update the messages like `rust-analyzer`. It will
+-- set use the variable timer to schedule the updates.
+-- TODO: This could error if the lsp is disconnected, the timer should be
+-- stopped
+local function register_timer()
+  -- Guard the for an already defined timer
+  if timer ~= nil then
+    return
+  end
+  timer = vim.loop.new_timer()
+  -- Execute the timer every 100 milliseconds
+  -- NOTE: This could be 30 to get a 30 updates per seconds, but set to 100 to
+  -- copy coc.nvim status interval
+  timer:start(0, 100, vim.schedule_wrap(timer_callback))
+end
+
+local M = {
+  timer = timer,
+  register_timer = register_timer,
+}
+
+return M