neovim(lualine): add git_status component

neovim/.config/nvim/after/plugin/lualine.lua

@@ -1,6 +1,34 @@
 local lualine = require("lualine")
 local devicons = require("nvim-web-devicons")
 
+local gstatus = { ahead = 0, behind = 0 }
+local function update_gstatus()
+  local Job = require("plenary.job")
+  Job:new({
+    command = "git",
+    args = { "rev-list", "--left-right", "--count", "HEAD...@{upstream}" },
+    on_exit = function(job, _)
+      local res = job:result()[1]
+      if type(res) ~= "string" then
+        gstatus = { ahead = 0, behind = 0 }
+        return
+      end
+      local ok, ahead, behind = pcall(string.match, res, "(%d+)%s*(%d+)")
+      if not ok then
+        ahead, behind = 0, 0
+      end
+      gstatus = { ahead = ahead, behind = behind }
+    end,
+  }):start()
+end
+
+if _G.Gstatus_timer == nil then
+  _G.Gstatus_timer = vim.loop.new_timer()
+else
+  _G.Gstatus_timer:stop()
+end
+_G.Gstatus_timer:start(0, 2000, vim.schedule_wrap(update_gstatus))
+
 local mode = {
   "mode",
 }
@@ -102,6 +130,12 @@ local tabs = {
   },
 }
 
+local git_status = {
+  function()
+    return "勒" .. gstatus.ahead .. " " .. gstatus.behind .. ""
+  end,
+}
+
 lualine.setup({
   options = {
     component_separators = "",
@@ -125,7 +159,7 @@ lualine.setup({
   sections = {
     lualine_a = { mode },
     lualine_b = { branch },
-    lualine_c = { diagnostics },
+    lualine_c = { diagnostics, git_status },
     lualine_x = { diff, location, tabstop, fileformat },
     lualine_y = { filetype },
     lualine_z = {},