perf improvement for system commands (issue #126)

lua/fzf-lua/cmd.lua

@@ -68,7 +68,7 @@ end
 local function run_command(args)
   local user_opts = args or {}
   if next(user_opts) == nil and not user_opts.cmd then
-    utils.info("[Fzf-lua] missing command args")
+    utils.info("missing command args")
     return
   end
 

lua/fzf-lua/core.lua

@@ -158,8 +158,8 @@ local get_diff_files = function(opts)
     local diff_files = {}
     local cmd = opts.git_status_cmd or config.globals.files.git_status_cmd
     if not cmd then return {} end
-    local status = vim.fn.systemlist(path.git_cwd(cmd, opts.cwd))
-    if not utils.shell_error() then
+    local status, err = utils.io_systemlist(path.git_cwd(cmd, opts.cwd))
+    if err == 0 then
         for i = 1, #status do
           local icon = status[i]:match("[MUDAR?]+")
           local file = status[i]:match("[^ ]*$")

lua/fzf-lua/init.lua

@@ -32,6 +32,8 @@ function M.setup(opts)
   if bat_theme and #bat_theme > 0 then
     vim.env.BAT_THEME = bat_theme
   end
+  -- set lua_io if caller requested
+  utils.set_lua_io(globals.lua_io)
   -- reset our globals based on user opts
   -- this doesn't happen automatically
   config.globals = globals

lua/fzf-lua/path.lua

@@ -172,8 +172,8 @@ end
 
 function M.git_root(cwd, noerr)
     local cmd = M.git_cwd("git rev-parse --show-toplevel", cwd)
-    local output = vim.fn.systemlist(cmd)
-    if utils.shell_error() then
+    local output, err = utils.io_systemlist(cmd)
+    if err ~= 0 then
         if not noerr then utils.info(unpack(output)) end
         return nil
     end

lua/fzf-lua/utils.lua

@@ -327,4 +327,48 @@ function M.ft_detect(ext)
   return ft
 end
 
+-- speed up exteral commands (issue #126)
+local _use_lua_io = false
+function M.set_lua_io(b)
+  _use_lua_io = b
+  if _use_lua_io then
+    M.warn("using experimental feature 'lua_io'")
+  end
+end
+
+function M.io_systemlist(cmd, use_lua_io)
+  if not use_lua_io then use_lua_io = _use_lua_io end
+  if use_lua_io then
+    local rc = 0
+    local stdout = ''
+    local handle = io.popen(cmd .. " 2>&1; echo $?", "r")
+    if handle then
+      stdout = {}
+      for h in handle:lines() do
+        stdout[#stdout + 1] = h
+      end
+      -- last line contains the exit status
+      rc = tonumber(stdout[#stdout])
+      stdout[#stdout] = nil
+    end
+    handle:close()
+    return stdout, rc
+  else
+    return vim.fn.systemlist(cmd), vim.v.shell_error
+  end
+end
+
+function M.io_system(cmd, use_lua_io)
+  if not use_lua_io then use_lua_io = _use_lua_io end
+  if use_lua_io then
+    local stdout, rc = M.io_systemlist(cmd, true)
+    if type(stdout) == 'table' then
+      stdout = table.concat(stdout, "\n")
+    end
+    return stdout, rc
+  else
+    return vim.fn.system(cmd), vim.v.shell_error
+  end
+end
+
 return M