major performance improvement: process entries externally, READ BELOW:

Since LUA is single threaded I reached a limit to performance
optimization, both 'git_icons' and 'file_icons' require string
matching and manipulations which eventually hurt performance
when running on large amount of files.
In order to solve that this commit introduces the option to spawn
commands and process the entries in a separate neovim process which
prints to stdio as if it was a regular shell command. This speeds up
things significantly and also makes the UI super responsive as if fzf
was run in the shell. This required a few lua hacks to be able to load
nvim-web-devicons in a '--headless --clean' instance and sharing the
user configuration through the RPC interface from the running instance.
This is enabled by default for 'files' and 'grep' providers and can also
be enabled for 'git.files' if required, control using the 'multiprocess'
option.

Author: ibhagwan

README.md

@@ -380,6 +380,7 @@ require'fzf-lua'.setup {
   files = {
     -- previewer      = "cat",          -- uncomment to override previewer
     prompt            = 'Files❯ ',
+    multiprocess      = true,           -- run command in a separator process
     git_icons         = true,           -- show git icons?
     file_icons        = true,           -- show file icons?
     color_icons       = true,           -- colorize file|git icons
@@ -410,6 +411,7 @@ require'fzf-lua'.setup {
   git = {
     files = {
       prompt          = 'GitFiles❯ ',
+      multiprocess    = false,          -- run command in a separator process
       cmd             = 'git ls-files --exclude-standard',
       git_icons       = true,           -- show git icons?
       file_icons      = true,           -- show file icons?
@@ -463,6 +465,7 @@ require'fzf-lua'.setup {
   grep = {
     prompt            = 'Rg❯ ',
     input_prompt      = 'Grep For❯ ',
+    multiprocess      = true,           -- run command in a separator process
     git_icons         = true,           -- show git icons?
     file_icons        = true,           -- show file icons?
     color_icons       = true,           -- colorize file|git icons

doc/fzf-lua.txt

@@ -414,6 +414,7 @@ Consult the list below for available settings:
       files = {
         -- previewer      = "cat",          -- uncomment to override previewer
         prompt            = 'Files❯ ',
+        multiprocess      = true,           -- run command in a separator process
         git_icons         = true,           -- show git icons?
         file_icons        = true,           -- show file icons?
         color_icons       = true,           -- colorize file|git icons
@@ -444,6 +445,7 @@ Consult the list below for available settings:
       git = {
         files = {
           prompt          = 'GitFiles❯ ',
+          multiprocess    = false,          -- run command in a separator process
           cmd             = 'git ls-files --exclude-standard',
           git_icons       = true,           -- show git icons?
           file_icons      = true,           -- show file icons?
@@ -497,6 +499,7 @@ Consult the list below for available settings:
       grep = {
         prompt            = 'Rg❯ ',
         input_prompt      = 'Grep For❯ ',
+        multiprocess      = true,           -- run command in a separator process
         git_icons         = true,           -- show git icons?
         file_icons        = true,           -- show file icons?
         color_icons       = true,           -- colorize file|git icons

lua/fzf-lua/config.lua

@@ -12,13 +12,13 @@ local M = {}
 
 M._has_devicons, M._devicons = pcall(require, "nvim-web-devicons")
 
--- if the caller has devicons lazy loaded
--- this will generate an error
---  nvim-web-devicons.lua:972: E5560:
---  nvim_command must not be called in a lua loop callback
-if M._has_devicons and not M._devicons.has_loaded() then
-  M._devicons.setup()
-end
+M._devicons_path = (function()
+  for _, p in ipairs(vim.api.nvim_list_runtime_paths()) do
+    if path.tail(p) == "nvim-web-devicons" then
+      return path.join({p, "lua/nvim-web-devicons.lua"})
+    end
+  end
+end)()
 
 function M._default_previewer_fn()
   return M.globals.default_previewer or M.globals.winopts.preview.default
@@ -162,6 +162,7 @@ M.globals.files = {
     previewer           = M._default_previewer_fn,
     prompt              = '> ',
     cmd                 = nil,  -- default: auto detect find|fd
+    multiprocess        = true,
     file_icons          = true and M._has_devicons,
     color_icons         = true,
     git_icons           = true,
@@ -239,6 +240,7 @@ M.globals.grep = {
     prompt              = 'Rg> ',
     input_prompt        = 'Grep For> ',
     cmd                 = nil,  -- default: auto detect rg|grep
+    multiprocess        = true,
     file_icons          = true and M._has_devicons,
     color_icons         = true,
     git_icons           = true,
@@ -496,20 +498,7 @@ M.globals.nvim = {
 
 M.globals.file_icon_padding = ''
 
-if M._has_devicons then
-  M.globals.file_icon_colors = {}
-
-  local function hex(hex)
-    local r,g,b = hex:match('.(..)(..)(..)')
-    r, g, b = tonumber(r, 16), tonumber(g, 16), tonumber(b, 16)
-    return r, g, b
-  end
-
-  for ext, info in pairs(M._devicons.get_icons()) do
-    local r, g, b = hex(info.color)
-    utils.add_ansi_code('DevIcon' .. info.name, string.format('[38;2;%s;%s;%sm', r, g, b))
-  end
-else
+if not M._has_devicons then
   M.globals.file_icon_colors = {
     ["lua"]       = "blue",
     ["rockspec"]  = "magenta",

lua/fzf-lua/core.lua

@@ -7,6 +7,7 @@ local actions = require "fzf-lua.actions"
 local win = require "fzf-lua.win"
 local libuv = require "fzf-lua.libuv"
 local shell = require "fzf-lua.shell"
+local make_entry = require "fzf-lua.make_entry"
 
 local M = {}
 
@@ -51,30 +52,14 @@ M.fzf = function(opts, contents)
   fzf_win:create()
   local selected, exit_code = fzf.raw_fzf(contents, M.build_fzf_cli(opts),
     { fzf_binary = opts.fzf_bin, fzf_cwd = opts.cwd })
-  utils.process_kill(opts._pid)
+  libuv.process_kill(opts._pid)
   fzf_win:check_exit_status(exit_code)
   if fzf_win:autoclose() == nil or fzf_win:autoclose() then
     fzf_win:close()
   end
   return selected
 end
 
-M.get_devicon = function(file, ext)
-  local icon, hl
-  if config._has_devicons and config._devicons then
-    icon, hl  = config._devicons.get_icon(file, ext:lower(), {default = true})
-  else
-    icon, hl = '', 'dark_grey'
-  end
-
-  -- allow user override of the color
-  local override = config.globals.file_icon_colors[ext]
-  if override then
-      hl = override
-  end
-
-  return icon..config.globals.file_icon_padding:gsub(" ", utils.nbsp), hl
-end
 
 M.preview_window = function(o)
   local preview_args = ("%s:%s:%s:"):format(
@@ -209,24 +194,72 @@ M.build_fzf_cli = function(opts)
   return cli_args .. extra_args
 end
 
-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, err = utils.io_systemlist(path.git_cwd(cmd, opts.cwd))
-    if err == 0 then
-        for i = 1, #status do
-          local icon = status[i]:match("[MUDARC?]+")
-          local file = status[i]:match("[^ ]*$")
-          if icon and file then
-            diff_files[file] = icon
-          end
+M.mt_cmd_wrapper = function(opts)
+  assert(opts and opts.cmd)
+
+  local str_to_str = function(s)
+    return "[[" .. s:gsub('[%]]', function(x) return "\\"..x end) .. "]]"
+  end
+
+  local opts_to_str = function(o)
+    local names = {
+      "debug",
+      "cmd",
+      "cwd",
+      "git_icons",
+      "file_icons",
+      "color_icons",
+      "strip_cwd_prefix",
+    }
+    local str = ""
+    for _, name in ipairs(names) do
+      if o[name] ~= nil then
+        if #str>0 then str = str..',' end
+        local val = o[name]
+        if type(val) == 'string' then
+          val = str_to_str(val)
         end
+        if type(val) == 'table' then
+          val = vim.inspect(val)
+        end
+        str = str .. ("%s=%s"):format(name, val)
+      end
     end
+    return '{'..str..'}'
+  end
 
-    return diff_files
+  if not opts.git_icons and not opts.file_icons then
+    -- command does not require any processing
+    return opts.cmd
+  elseif opts.multiprocess then
+    local fn_preprocess = [[return require("make_entry").preprocess]]
+    local fn_transform = [[return require("make_entry").file]]
+    if not opts.no_remote_config then
+      fn_transform = ([[_G._fzf_lua_server=%s; %s]]):format(
+        vim.fn.shellescape(vim.g.fzf_lua_server),
+        fn_transform)
+    end
+    if config._devicons_path then
+      fn_transform = ([[_G._devicons_path=%s; %s]]) :format(
+          vim.fn.shellescape(config._devicons_path),
+          fn_transform)
+    end
+    local cmd = libuv.wrap_spawn_stdio(opts_to_str(opts),
+      fn_transform, fn_preprocess)
+    if opts.debug then print(cmd) end
+    return cmd
+  else
+    return libuv.spawn_nvim_fzf_cmd(opts,
+      function(x)
+        return make_entry.file(opts, x)
+      end)
+  end
 end
 
+-- shortcuts to make_entry
+M.get_devicon = make_entry.get_devicon
+M.make_entry_file = make_entry.file
+
 M.make_entry_lcol = function(_, entry)
   if not entry then return nil end
   local filename = entry.filename or vim.api.nvim_buf_get_name(entry.bufnr)
@@ -238,58 +271,6 @@ M.make_entry_lcol = function(_, entry)
     entry.text)
 end
 
-M.make_entry_file = function(opts, x)
-  local icon, hl
-  local ret = {}
-  local file = utils.strip_ansi_coloring(string.match(x, '[^:]*'))
-  if opts.cwd_only and path.starts_with_separator(file) then
-    local cwd = opts.cwd or vim.loop.cwd()
-    if not path.is_relative(file, cwd) then
-      return nil
-    end
-  end
-  -- fd v8.3 requires adding '--strip-cwd-prefix' to remove
-  -- the './' prefix, will not work with '--color=always'
-  -- https://github.com/sharkdp/fd/blob/master/CHANGELOG.md
-  if not (opts.strip_cwd_prefix == false) and path.starts_with_cwd(x) then
-     x = x:sub(3)
-  end
-  if opts.cwd and #opts.cwd > 0 then
-    -- TODO: does this work if there are ANSI escape codes in x?
-    x = path.relative(x, opts.cwd)
-  end
-  if opts.file_icons then
-    local filename = path.tail(file)
-    local ext = path.extension(filename)
-    icon, hl = M.get_devicon(filename, ext)
-    if opts.color_icons then
-      -- extra workaround for issue #119 (or similars)
-      -- use default if we can't find the highlight ansi
-      local fn = utils.ansi_codes[hl] or utils.ansi_codes['dark_grey']
-      icon = fn(icon)
-    end
-    ret[#ret+1] = icon
-    ret[#ret+1] = utils.nbsp
-  end
-  if opts.git_icons then
-    local indicators = opts.diff_files and opts.diff_files[file] or utils.nbsp
-    for i=1,#indicators do
-      icon = indicators:sub(i,i)
-      local git_icon = config.globals.git.icons[icon]
-      if git_icon then
-        icon = git_icon.icon
-        if opts.color_icons then
-          icon = utils.ansi_codes[git_icon.color or "dark_grey"](icon)
-        end
-      end
-      ret[#ret+1] = icon
-    end
-    ret[#ret+1] = utils.nbsp
-  end
-  ret[#ret+1] = x
-  return table.concat(ret)
-end
-
 M.set_fzf_line_args = function(opts)
   opts._line_placeholder = 2
   -- delimiters are ':' and <tab>
@@ -336,6 +317,7 @@ M.set_header = function(opts, type)
   return opts
 end
 
+
 M.fzf_files = function(opts, contents)
 
   if not opts then return end
@@ -345,13 +327,8 @@ M.fzf_files = function(opts, contents)
 
   coroutine.wrap(function ()
 
-    if opts.cwd_only and not opts.cwd then
-      opts.cwd = vim.loop.cwd()
-    end
-
-    if opts.git_icons then
-      opts.diff_files = get_diff_files(opts)
-    end
+    -- setup opts.cwd and git diff files
+    make_entry.preprocess(opts)
 
     local selected = M.fzf(opts, contents or opts.fzf_fn)
 
@@ -385,7 +362,7 @@ M.set_fzf_interactive_cmd = function(opts)
   -- fzf already adds single quotes around the placeholder when expanding
   -- for skim we surround it with double quotes or single quote searches fail
   local placeholder = utils._if(opts._is_skim, '"{}"', '{q}')
-  local raw_async_act = libuv.spawn_reload_cmd_action(opts, placeholder)
+  local raw_async_act = shell.reload_action_cmd(opts, placeholder)
   return M.set_fzf_interactive(opts, raw_async_act, placeholder)
 end
 
@@ -460,10 +437,8 @@ M.set_fzf_interactive = function(opts, act_cmd, placeholder)
     -- around the place holder
     opts.fzf_fn = {}
     if opts.exec_empty_query or (query and #query>0) then
-      opts.fzf_fn = libuv.spawn_nvim_fzf_cmd(
-        { cmd = act_cmd:gsub(placeholder,
-          #query>0 and utils.lua_escape(vim.fn.shellescape(query)) or "''"),
-          cwd = opts.cwd, pid_cb = opts._pid_cb })
+      opts.fzf_fn = act_cmd:gsub(placeholder,
+          #query>0 and utils.lua_escape(vim.fn.shellescape(query)) or "''")
     end
     opts.fzf_opts['--phony'] = ''
     opts.fzf_opts['--query'] = vim.fn.shellescape(query)

lua/fzf-lua/init.lua

@@ -20,18 +20,14 @@ do
     end
   end
 
-  -- Since 'nvim_fzf.vim' doesn't get called we
-  -- have to manually set 'g:nvim_fzf_directory'
-  if not vim.g.nvim_fzf_directory then
-    local nvim_fzf_directory = path.join({
-      path.parent(path.parent(path.parent(path.parent(currFile)))),
-      "nvim-fzf"
-    })
-    if vim.loop.fs_stat(nvim_fzf_directory) then
-      vim.g.nvim_fzf_directory = nvim_fzf_directory
-    end
-    -- utils.info(("vim.g.nvim_fzf_directory = '%s'"):format(nvim_fzf_directory))
+  -- Create a new RPC server (tmp socket) to listen to messages (actions/headless)
+  -- this is safer than using $NVIM_LISTEN_ADDRESS. If the user is using a custom
+  -- fixed $NVIM_LISTEN_ADDRESS different neovim instances will use the same path
+  -- as their address and messages won't be recieved on older instances
+  if not vim.g.fzf_lua_server then
+    vim.g.fzf_lua_server = vim.fn.serverstart()
   end
+
 end
 
 local M = {}