feat(Man): port to Lua (#19912)

Co-authored-by: zeertzjq <zeertzjq@outlook.com>

runtime/lua/man.lua

@@ -1,7 +1,75 @@
 require('vim.compat')
 
+local api, fn = vim.api, vim.fn
+
+local find_arg = '-w'
+local localfile_arg = true -- Always use -l if possible. #6683
 local buf_hls = {}
 
+local M = {}
+
+local function man_error(msg)
+  M.errormsg = 'man.lua: ' .. vim.inspect(msg)
+  error(M.errormsg)
+end
+
+-- Run a system command and timeout after 30 seconds.
+local function man_system(cmd, silent)
+  local stdout_data = {}
+  local stderr_data = {}
+  local stdout = vim.loop.new_pipe(false)
+  local stderr = vim.loop.new_pipe(false)
+
+  local done = false
+  local exit_code
+
+  local handle = vim.loop.spawn(cmd[1], {
+    args = vim.list_slice(cmd, 2),
+    stdio = { nil, stdout, stderr },
+  }, function(code)
+    exit_code = code
+    stdout:close()
+    stderr:close()
+    done = true
+  end)
+
+  if handle then
+    stdout:read_start(function(_, data)
+      stdout_data[#stdout_data + 1] = data
+    end)
+    stderr:read_start(function(_, data)
+      stderr_data[#stderr_data + 1] = data
+    end)
+  else
+    stdout:close()
+    stderr:close()
+    if not silent then
+      man_error(string.format('command error: %s', table.concat(cmd)))
+    end
+  end
+
+  vim.wait(30000, function()
+    return done
+  end)
+
+  if not done then
+    if handle then
+      vim.loop.shutdown(handle)
+      stdout:close()
+      stderr:close()
+    end
+    man_error(string.format('command timed out: %s', table.concat(cmd, ' ')))
+  end
+
+  if exit_code ~= 0 and not silent then
+    man_error(
+      string.format("command error '%s': %s", table.concat(cmd, ' '), table.concat(stderr_data))
+    )
+  end
+
+  return table.concat(stdout_data)
+end
+
 local function highlight_line(line, linenr)
   local chars = {}
   local prev_char = ''
@@ -152,21 +220,540 @@ local function highlight_line(line, linenr)
 end
 
 local function highlight_man_page()
-  local mod = vim.api.nvim_buf_get_option(0, 'modifiable')
-  vim.api.nvim_buf_set_option(0, 'modifiable', true)
+  local mod = vim.bo.modifiable
+  vim.bo.modifiable = true
 
-  local lines = vim.api.nvim_buf_get_lines(0, 0, -1, false)
+  local lines = api.nvim_buf_get_lines(0, 0, -1, false)
   for i, line in ipairs(lines) do
     lines[i] = highlight_line(line, i)
   end
-  vim.api.nvim_buf_set_lines(0, 0, -1, false, lines)
+  api.nvim_buf_set_lines(0, 0, -1, false, lines)
 
   for _, args in ipairs(buf_hls) do
-    vim.api.nvim_buf_add_highlight(unpack(args))
+    api.nvim_buf_add_highlight(unpack(args))
   end
   buf_hls = {}
 
-  vim.api.nvim_buf_set_option(0, 'modifiable', mod)
+  vim.bo.modifiable = mod
 end
 
-return { highlight_man_page = highlight_man_page }
+-- replace spaces in a man page name with underscores
+-- intended for PostgreSQL, which has man pages like 'CREATE_TABLE(7)';
+-- while editing SQL source code, it's nice to visually select 'CREATE TABLE'
+-- and hit 'K', which requires this transformation
+local function spaces_to_underscores(str)
+  local res = str:gsub('%s', '_')
+  return res
+end
+
+local function get_path(sect, name, silent)
+  name = name or ''
+  sect = sect or ''
+  -- Some man implementations (OpenBSD) return all available paths from the
+  -- search command. Previously, this function would simply select the first one.
+  --
+  -- However, some searches will report matches that are incorrect:
+  -- man -w strlen may return string.3 followed by strlen.3, and therefore
+  -- selecting the first would get us the wrong page. Thus, we must find the
+  -- first matching one.
+  --
+  -- There's yet another special case here. Consider the following:
+  -- If you run man -w strlen and string.3 comes up first, this is a problem. We
+  -- should search for a matching named one in the results list.
+  -- However, if you search for man -w clock_gettime, you will *only* get
+  -- clock_getres.2, which is the right page. Searching the resuls for
+  -- clock_gettime will no longer work. In this case, we should just use the
+  -- first one that was found in the correct section.
+  --
+  -- Finally, we can avoid relying on -S or -s here since they are very
+  -- inconsistently supported. Instead, call -w with a section and a name.
+  local cmd
+  if sect == '' then
+    cmd = { 'man', find_arg, name }
+  else
+    cmd = { 'man', find_arg, sect, name }
+  end
+
+  local lines = man_system(cmd, silent)
+  if lines == nil then
+    return nil
+  end
+
+  local results = vim.split(lines, '\n', { trimempty = true })
+
+  if #results == 0 then
+    return
+  end
+
+  -- find any that match the specified name
+  local namematches = vim.tbl_filter(function(v)
+    return fn.fnamemodify(v, ':t'):match(name)
+  end, results) or {}
+  local sectmatches = {}
+
+  if #namematches > 0 and sect ~= '' then
+    sectmatches = vim.tbl_filter(function(v)
+      return fn.fnamemodify(v, ':e') == sect
+    end, namematches)
+  end
+
+  return fn.substitute(sectmatches[1] or namematches[1] or results[1], [[\n\+$]], '', '')
+end
+
+local function matchstr(text, pat_or_re)
+  local re = type(pat_or_re) == 'string' and vim.regex(pat_or_re) or pat_or_re
+
+  local s, e = re:match_str(text)
+
+  if s == nil then
+    return
+  end
+
+  return text:sub(vim.str_utfindex(text, s) + 1, vim.str_utfindex(text, e))
+end
+
+-- attempt to extract the name and sect out of 'name(sect)'
+-- otherwise just return the largest string of valid characters in ref
+local function extract_sect_and_name_ref(ref)
+  ref = ref or ''
+  if ref:sub(1, 1) == '-' then -- try ':Man -pandoc' with this disabled.
+    man_error("manpage name cannot start with '-'")
+  end
+  local ref1 = ref:match('[^()]+%([^()]+%)')
+  if not ref1 then
+    local name = ref:match('[^()]+')
+    if not name then
+      man_error('manpage reference cannot contain only parentheses: ' .. ref)
+    end
+    return '', spaces_to_underscores(name)
+  end
+  local parts = vim.split(ref1, '(', { plain = true })
+  -- see ':Man 3X curses' on why tolower.
+  -- TODO(nhooyr) Not sure if this is portable across OSs
+  -- but I have not seen a single uppercase section.
+  local sect = vim.split(parts[2] or '', ')', { plain = true })[1]:lower()
+  local name = spaces_to_underscores(parts[1])
+  return sect, name
+end
+
+-- verify_exists attempts to find the path to a manpage
+-- based on the passed section and name.
+--
+-- 1. If manpage could not be found with the given sect and name,
+--    then try all the sections in b:man_default_sects.
+-- 2. If it still could not be found, then we try again without a section.
+-- 3. If still not found but $MANSECT is set, then we try again with $MANSECT
+--    unset.
+local function verify_exists(sect, name)
+  if sect and sect ~= '' then
+    local ret = get_path(sect, name, true)
+    if ret then
+      return ret
+    end
+  end
+
+  if vim.b.man_default_sects ~= nil then
+    local sects = vim.split(vim.b.man_default_sects, ',', { plain = true, trimempty = true })
+    for _, sec in ipairs(sects) do
+      local ret = get_path(sec, name, true)
+      if ret then
+        return ret
+      end
+    end
+  end
+
+  -- if none of the above worked, we will try with no section
+  local res_empty_sect = get_path('', name, true)
+  if res_empty_sect then
+    return res_empty_sect
+  end
+
+  -- if that still didn't work, we will check for $MANSECT and try again with it
+  -- unset
+  if vim.env.MANSECT then
+    local mansect = vim.env.MANSECT
+    vim.env.MANSECT = nil
+    local res = get_path('', name, true)
+    vim.env.MANSECT = mansect
+    if res then
+      return res
+    end
+  end
+
+  -- finally, if that didn't work, there is no hope
+  man_error('no manual entry for ' .. name)
+end
+
+local EXT_RE = vim.regex([[\.\%([glx]z\|bz2\|lzma\|Z\)$]])
+
+-- Extracts the name/section from the 'path/name.sect', because sometimes the actual section is
+-- more specific than what we provided to `man` (try `:Man 3 App::CLI`).
+-- Also on linux, name seems to be case-insensitive. So for `:Man PRIntf`, we
+-- still want the name of the buffer to be 'printf'.
+local function extract_sect_and_name_path(path)
+  local tail = fn.fnamemodify(path, ':t')
+  if EXT_RE:match_str(path) then -- valid extensions
+    tail = fn.fnamemodify(tail, ':r')
+  end
+  local name, sect = tail:match('^(.+)%.([^.]+)$')
+  return sect, name
+end
+
+local function find_man()
+  local win = 1
+  while win <= fn.winnr('$') do
+    local buf = fn.winbufnr(win)
+    if vim.bo[buf].filetype == 'man' then
+      vim.cmd(win .. 'wincmd w')
+      return true
+    end
+    win = win + 1
+  end
+  return false
+end
+
+local function set_options(pager)
+  vim.bo.swapfile = false
+  vim.bo.buftype = 'nofile'
+  vim.bo.bufhidden = 'hide'
+  vim.bo.modified = false
+  vim.bo.readonly = true
+  vim.bo.modifiable = false
+  vim.b.pager = pager
+  vim.bo.filetype = 'man'
+end
+
+local function get_page(path, silent)
+  -- Disable hard-wrap by using a big $MANWIDTH (max 1000 on some systems #9065).
+  -- Soft-wrap: ftplugin/man.lua sets wrap/breakindent/….
+  -- Hard-wrap: driven by `man`.
+  local manwidth
+  if (vim.g.man_hardwrap or 1) ~= 1 then
+    manwidth = 999
+  elseif vim.env.MANWIDTH then
+    manwidth = vim.env.MANWIDTH
+  else
+    manwidth = api.nvim_win_get_width(0)
+  end
+  -- Force MANPAGER=cat to ensure Vim is not recursively invoked (by man-db).
+  -- http://comments.gmane.org/gmane.editors.vim.devel/29085
+  -- Set MAN_KEEP_FORMATTING so Debian man doesn't discard backspaces.
+  local cmd = { 'env', 'MANPAGER=cat', 'MANWIDTH=' .. manwidth, 'MAN_KEEP_FORMATTING=1', 'man' }
+  if localfile_arg then
+    cmd[#cmd + 1] = '-l'
+  end
+  cmd[#cmd + 1] = path
+  return man_system(cmd, silent)
+end
+
+local function put_page(page)
+  vim.bo.modified = true
+  vim.bo.readonly = false
+  vim.bo.swapfile = false
+
+  api.nvim_buf_set_lines(0, 0, -1, false, vim.split(page, '\n'))
+
+  while fn.getline(1):match('^%s*$') do
+    api.nvim_buf_set_lines(0, 0, 1, false, {})
+  end
+  -- XXX: nroff justifies text by filling it with whitespace.  That interacts
+  -- badly with our use of $MANWIDTH=999.  Hack around this by using a fixed
+  -- size for those whitespace regions.
+  vim.cmd([[silent! keeppatterns keepjumps %s/\s\{199,}/\=repeat(' ', 10)/g]])
+  vim.cmd('1') -- Move cursor to first line
+  highlight_man_page()
+  set_options(false)
+end
+
+local function format_candidate(path, psect)
+  if matchstr(path, [[\.\%(pdf\|in\)$]]) then -- invalid extensions
+    return ''
+  end
+  local sect, name = extract_sect_and_name_path(path)
+  if sect == psect then
+    return name
+  elseif sect and name and matchstr(sect, psect .. '.\\+$') then -- invalid extensions
+    -- We include the section if the user provided section is a prefix
+    -- of the actual section.
+    return ('%s(%s)'):format(name, sect)
+  end
+  return ''
+end
+
+local function get_paths(sect, name, do_fallback)
+  -- callers must try-catch this, as some `man` implementations don't support `s:find_arg`
+  local ok, ret = pcall(function()
+    local mandirs =
+      table.concat(vim.split(man_system({ 'man', find_arg }), '[:\n]', { trimempty = true }), ',')
+    local paths = fn.globpath(mandirs, 'man?/' .. name .. '*.' .. sect .. '*', false, true)
+    pcall(function()
+      -- Prioritize the result from verify_exists as it obeys b:man_default_sects.
+      local first = verify_exists(sect, name)
+      paths = vim.tbl_filter(function(v)
+        return v ~= first
+      end, paths)
+      paths = { first, unpack(paths) }
+    end)
+    return paths
+  end)
+
+  if not ok then
+    if not do_fallback then
+      error(ret)
+    end
+
+    -- Fallback to a single path, with the page we're trying to find.
+    ok, ret = pcall(verify_exists, sect, name)
+
+    return { ok and ret or nil }
+  end
+  return ret or {}
+end
+
+local function complete(sect, psect, name)
+  local pages = get_paths(sect, name, false)
+  -- We remove duplicates in case the same manpage in different languages was found.
+  return fn.uniq(fn.sort(vim.tbl_map(function(v)
+    return format_candidate(v, psect)
+  end, pages) or {}, 'i'))
+end
+
+-- see extract_sect_and_name_ref on why tolower(sect)
+function M.man_complete(arg_lead, cmd_line, _)
+  local args = vim.split(cmd_line, '%s+', { trimempty = true })
+  local cmd_offset = fn.index(args, 'Man')
+  if cmd_offset > 0 then
+    -- Prune all arguments up to :Man itself. Otherwise modifier commands like
+    -- :tab, :vertical, etc. would lead to a wrong length.
+    args = vim.list_slice(args, cmd_offset + 1)
+  end
+
+  if #args > 3 then
+    return {}
+  end
+
+  if #args == 1 then
+    -- returning full completion is laggy. Require some arg_lead to complete
+    -- return complete('', '', '')
+    return {}
+  end
+
+  if arg_lead:match('^[^()]+%([^()]*$') then
+    -- cursor (|) is at ':Man printf(|' or ':Man 1 printf(|'
+    -- The later is is allowed because of ':Man pri<TAB>'.
+    -- It will offer 'priclass.d(1m)' even though section is specified as 1.
+    local tmp = vim.split(arg_lead, '(', { plain = true })
+    local name = tmp[1]
+    local sect = (tmp[2] or ''):lower()
+    return complete(sect, '', name)
+  end
+
+  if not args[2]:match('^[^()]+$') then
+    -- cursor (|) is at ':Man 3() |' or ':Man (3|' or ':Man 3() pri|'
+    -- or ':Man 3() pri |'
+    return {}
+  end
+
+  if #args == 2 then
+    local name, sect
+    if arg_lead == '' then
+      -- cursor (|) is at ':Man 1 |'
+      name = ''
+      sect = args[1]:lower()
+    else
+      -- cursor (|) is at ':Man pri|'
+      if arg_lead:match('/') then
+        -- if the name is a path, complete files
+        -- TODO(nhooyr) why does this complete the last one automatically
+        return fn.glob(arg_lead .. '*', false, true)
+      end
+      name = arg_lead
+      sect = ''
+    end
+    return complete(sect, sect, name)
+  end
+
+  if not arg_lead:match('[^()]+$') then
+    -- cursor (|) is at ':Man 3 printf |' or ':Man 3 (pr)i|'
+    return {}
+  end
+
+  -- cursor (|) is at ':Man 3 pri|'
+  local name = arg_lead
+  local sect = args[2]:lower()
+  return complete(sect, sect, name)
+end
+
+function M.goto_tag(pattern, _, _)
+  local sect, name = extract_sect_and_name_ref(pattern)
+
+  local paths = get_paths(sect, name, true)
+  local structured = {}
+
+  for _, path in ipairs(paths) do
+    sect, name = extract_sect_and_name_path(path)
+    if sect and name then
+      structured[#structured + 1] = {
+        name = name,
+        title = name .. '(' .. sect .. ')',
+      }
+    end
+  end
+
+  if vim.o.cscopetag then
+    -- return only a single entry so we work well with :cstag (#11675)
+    structured = { structured[1] }
+  end
+
+  return vim.tbl_map(function(entry)
+    return {
+      name = entry.name,
+      filename = 'man://' .. entry.title,
+      cmd = '1',
+    }
+  end, structured)
+end
+
+-- Called when Nvim is invoked as $MANPAGER.
+function M.init_pager()
+  if fn.getline(1):match('^%s*$') then
+    api.nvim_buf_set_lines(0, 0, 1, false, {})
+  else
+    vim.cmd('keepjumps 1')
+  end
+  highlight_man_page()
+  -- Guess the ref from the heading (which is usually uppercase, so we cannot
+  -- know the correct casing, cf. `man glDrawArraysInstanced`).
+  local ref = fn.substitute(matchstr(fn.getline(1), [[^[^)]\+)]]) or '', ' ', '_', 'g')
+  local ok, res = pcall(extract_sect_and_name_ref, ref)
+  vim.b.man_sect = ok and res or ''
+
+  if not fn.bufname('%'):match('man://') then -- Avoid duplicate buffers, E95.
+    vim.cmd.file({ 'man://' .. fn.fnameescape(ref):lower(), mods = { silent = true } })
+  end
+
+  set_options(true)
+end
+
+function M.open_page(count, smods, args)
+  if #args > 2 then
+    man_error('too many arguments')
+  end
+
+  local ref
+  if #args == 0 then
+    ref = vim.bo.filetype == 'man' and fn.expand('<cWORD>') or fn.expand('<cword>')
+    if ref == '' then
+      man_error('no identifier under cursor')
+    end
+  elseif #args == 1 then
+    ref = args[1]
+  else
+    -- Combine the name and sect into a manpage reference so that all
+    -- verification/extraction can be kept in a single function.
+    -- If args[2] is a reference as well, that is fine because it is the only
+    -- reference that will match.
+    ref = ('%s(%s)'):format(args[2], args[1])
+  end
+
+  local sect, name = extract_sect_and_name_ref(ref)
+  if count >= 0 then
+    sect = tostring(count)
+  end
+
+  local path = verify_exists(sect, name)
+  sect, name = extract_sect_and_name_path(path)
+
+  local buf = fn.bufnr()
+  local save_tfu = vim.bo[buf].tagfunc
+  vim.bo[buf].tagfunc = "v:lua.require'man'.goto_tag"
+
+  local target = ('%s(%s)'):format(name, sect)
+
+  local ok, ret = pcall(function()
+    if not smods.tab and find_man() then
+      vim.cmd.tag({ target, mods = { silent = true, keepalt = true } })
+    else
+      smods.silent = true
+      smods.keepalt = true
+      vim.cmd.stag({ target, mods = smods })
+    end
+  end)
+
+  vim.bo[buf].tagfunc = save_tfu
+
+  if not ok then
+    error(ret)
+  else
+    set_options(false)
+  end
+
+  vim.b.man_sect = sect
+end
+
+-- Called when a man:// buffer is opened.
+function M.read_page(ref)
+  local sect, name = extract_sect_and_name_ref(ref)
+  local path = verify_exists(sect, name)
+  sect = extract_sect_and_name_path(path)
+  local page = get_page(path)
+  vim.b.man_sect = sect
+  put_page(page)
+end
+
+function M.show_toc()
+  local bufname = fn.bufname('%')
+  local info = fn.getloclist(0, { winid = 1 })
+  if info ~= '' and vim.w[info.winid].qf_toc == bufname then
+    vim.cmd.lopen()
+    return
+  end
+
+  local toc = {}
+  local lnum = 2
+  local last_line = fn.line('$') - 1
+  local section_title_re = vim.regex([[^\%( \{3\}\)\=\S.*$]])
+  local flag_title_re = vim.regex([[^\s\+\%(+\|-\)\S\+]])
+  while lnum and lnum < last_line do
+    local text = fn.getline(lnum)
+    if section_title_re:match_str(text) then
+      -- if text is a section title
+      toc[#toc + 1] = {
+        bufnr = fn.bufnr('%'),
+        lnum = lnum,
+        text = text,
+      }
+    elseif flag_title_re:match_str(text) then
+      -- if text is a flag title. we strip whitespaces and prepend two
+      -- spaces to have a consistent format in the loclist.
+      toc[#toc + 1] = {
+        bufnr = fn.bufnr('%'),
+        lnum = lnum,
+        text = '  ' .. fn.substitute(text, [[^\s*\(.\{-}\)\s*$]], [[\1]], ''),
+      }
+    end
+    lnum = fn.nextnonblank(lnum + 1)
+  end
+
+  fn.setloclist(0, toc, ' ')
+  fn.setloclist(0, {}, 'a', { title = 'Man TOC' })
+  vim.cmd.lopen()
+  vim.w.qf_toc = bufname
+end
+
+local function init()
+  local path = get_path('', 'man', true)
+  local page
+  if path ~= nil then
+    -- Check for -l support.
+    page = get_page(path, true)
+  end
+
+  if page == '' or page == nil then
+    localfile_arg = false
+  end
+end
+
+init()
+
+return M