[mini.starter]: Optimize section recent files?

[abeldekat]

Contributing guidelines

• I have read CODE_OF_CONDUCT.md

Module(s)

mini.starter

Question

Currently, for each item in v:oldfiles, mini.starter determines if the file exists. However, the number of items actually displayed in the recent files section can be much lower.

Worst case, v:oldfiles can contain 100 items, where mini.starter only displays 5 by default. On each startup, mini.starter would query unnecessarily for 95 items.

The code can be optimized:

MiniStarter.sections.recent_files = function(n, current_dir, show_path)
  n = n or 5
  if current_dir == nil then current_dir = false end

  if show_path == nil then show_path = true end
  if show_path == false then show_path = function() return '' end end
  if show_path == true then
    show_path = function(path) return string.format(' (%s)', vim.fn.fnamemodify(path, ':~:.')) end
  end
  if not vim.is_callable(show_path) then H.error('`show_path` should be boolean or callable.') end

  return function()
    local section = string.format('Recent files%s', current_dir and ' (current directory)' or '')
    local sep = vim.loop.os_uname().sysname == 'Windows_NT' and [[%\]] or '%/'
    local cwd_pattern = '^' .. vim.pesc(vim.fn.getcwd()) .. sep

    local n_added = 0
    local files = vim.tbl_filter(function(f)
      -- Return early if there are enough items in the list
      if n_added == n then return false end

      -- Use only actual readable files
      local result = vim.fn.filereadable(f) == 1
      if current_dir then
        -- Filter files from current directory and its subdirectories
        result = result and f:find(cwd_pattern) ~= nil
      end
      n_added = result and n_added + 1 or n_added
      return result
    end, vim.v.oldfiles or {})

    if #files == 0 then
      local text = current_dir and 'There are no recent files in current directory'
        or 'There are no recent files (`v:oldfiles` is empty)'
      return { { name = text, action = '', section = section } }
    end

    -- Create items
    local items = {}
    for _, f in ipairs(files) do
      local name = vim.fn.fnamemodify(f, ':t') .. show_path(f)
      table.insert(items, { action = function() H.edit(f) end, name = name, section = section })
    end

    return items
  end

Using the code above all tests pass.

Would you allow a PR? If so, I'd also think that one message is sufficient in case the list is empty: There are no recent files

[echasnovski]

Worst case, v:oldfiles can contain 100 items, where mini.starter only displays 5 by default. On each startup, mini.starter would query unnecessarily for 95 items.

I don't think it has huge impact, but can be optimized, yeah.

Would you allow a PR?

Sure. Just not with tbl_filter, but a regular for ... do which uses break if there are n readable files found.

If so, I'd also think that one message is sufficient in case the list is empty: There are no recent files

I think preserving current different messages which show more info is less ambiguous and better here.

[abeldekat]

PR