" Vim plug-in
" Author: Peter Odding <peter@peterodding.com>
" Last Change: July 9, 2011
" URL: http://peterodding.com/code/vim/easytags/
" Requires: Exuberant Ctags (http://ctags.sf.net)

" Support for automatic update using the GLVS plug-in.
" GetLatestVimScripts: 3114 1 :AutoInstall: easytags.zip

" Don't source the plug-in when it's already been loaded or &compatible is set.
if &cp || exists('g:loaded_easytags')
  finish
endif

let g:easytags_version = '2.4.11'

" Configuration defaults and initialization. {{{1

if !exists('g:easytags_file')
  if xolox#misc#os#is_win()
    let g:easytags_file = '~\_vimtags'
  else
    let g:easytags_file = '~/.vimtags'
  endif
endif

if !exists('g:easytags_by_filetype')
  let g:easytags_by_filetype = ''
endif

if !exists('g:easytags_events')
  let g:easytags_events = []
  if !exists('g:easytags_on_cursorhold') || g:easytags_on_cursorhold
    call extend(g:easytags_events, ['CursorHold', 'CursorHoldI'])
  endif
  if exists('g:easytags_always_enabled') && g:easytags_always_enabled
    call extend(g:easytags_events, ['BufReadPost', 'BufWritePost', 'FocusGained', 'ShellCmdPost', 'ShellFilterPost'])
  endif
endif

if !exists('g:easytags_ignored_filetypes')
  let g:easytags_ignored_filetypes = '^tex$'
endif

if !exists('g:easytags_python_script')
  let g:easytags_python_script = expand('<sfile>:p:h') . '/../misc/easytags/highlight.py'
endif

function! s:InitEasyTags(version)
  " Check that the location of Exuberant Ctags has been configured or that the
  " correct version of the program exists in one of its default locations.
  if exists('g:easytags_cmd') && s:CheckCtags(g:easytags_cmd, a:version)
    return 1
  endif
  " On Ubuntu Linux, Exuberant Ctags is installed as `ctags'. On Debian Linux,
  " Exuberant Ctags is installed as `exuberant-ctags'. On Free-BSD, Exuberant
  " Ctags is installed as `exctags'.
  for name in ['ctags', 'exuberant-ctags', 'exctags']
    if s:CheckCtags(name, a:version)
      let g:easytags_cmd = name
      return 1
    endif
  endfor
endfunction

function! s:CheckCtags(name, version)
  " Not every executable out there named `ctags' is in fact Exuberant Ctags.
  " This function makes sure it is because the easytags plug-in requires the
  " --list-languages option (and more).
  if executable(a:name)
    let command = a:name . ' --version'
    try
      let listing = join(xolox#shell#execute(command, 1), '\n')
    catch /^Vim\%((\a\+)\)\=:E117/
      " Ignore missing shell.vim plug-in.
      let listing = system(command)
    catch
      " xolox#shell#execute() converts shell errors to exceptions and since
      " we're checking whether one of several executables exists we don't want
      " to throw an error when the first one doesn't!
      return
    endtry
    let pattern = 'Exuberant Ctags \zs\(\d\+\(\.\d\+\)*\|Development\)'
    let g:easytags_ctags_version = matchstr(listing, pattern)
    if g:easytags_ctags_version == 'Development'
      return 1
    else
      return s:VersionToNumber(g:easytags_ctags_version) >= a:version
    endif
  endif
endfunction

function! s:VersionToNumber(s)
  let values = split(a:s, '\.')
  if len(values) == 1
    return values[0] * 10
  elseif len(values) >= 2
    return values[0] * 10 + values[1][0]
  endif
endfunction

if !s:InitEasyTags(55)
  if exists('g:easytags_suppress_ctags_warning') && g:easytags_suppress_ctags_warning
    finish
  endif
  if !exists('g:easytags_ctags_version') || empty(g:easytags_ctags_version)
    let s:msg = "easytags.vim %s: Plug-in not loaded because Exuberant Ctags isn't installed!"
    if executable('apt-get')
      let s:msg .= " On Ubuntu & Debian you can install Exuberant Ctags by"
      let s:msg .= " installing the package named `exuberant-ctags':"
      let s:msg .= " sudo apt-get install exuberant-ctags"
    else
      let s:msg .= " Please download & install Exuberant Ctags from http://ctags.sf.net"
    endif
    echomsg printf(s:msg, g:easytags_version)
  else
    let s:msg = "easytags.vim %s: Plug-in not loaded because Exuberant Ctags 5.5"
    let s:msg .= " or newer is required while you have version %s installed!"
    echomsg printf(s:msg, g:easytags_version, g:easytags_ctags_version)
  endif
  unlet s:msg
  finish
endif

" The plug-in initializes the &tags option as soon as possible so that the
" global tags file is available when using "vim -t some_tag". If &tags is
" reset, we'll try again on the "VimEnter" automatic command event (below).
call xolox#easytags#register(1)

" The :UpdateTags and :HighlightTags commands. {{{1

command! -bar -bang -nargs=* -complete=file UpdateTags call xolox#easytags#update(0, <q-bang> == '!', [<f-args>])
command! -bar HighlightTags call xolox#easytags#highlight()
command! -bang TagsByFileType call xolox#easytags#by_filetype(<q-bang> == '!')

" Automatic commands. {{{1

augroup PluginEasyTags
  autocmd!
  " This is the alternative way of registering the global tags file using
  " the automatic command event "VimEnter". Apparently this makes the
  " plug-in behave better when used together with tplugin?
  autocmd VimEnter * call xolox#easytags#register(1)
  " Define the automatic commands to perform updating/highlighting.
  for s:eventname in g:easytags_events
    execute 'autocmd'  s:eventname '* call xolox#easytags#autoload()'
  endfor
  " Define an automatic command to register file type specific tags files?
  if !empty(g:easytags_by_filetype)
    autocmd FileType * call xolox#easytags#register(0)
  endif
  " After reloading a buffer the dynamic syntax highlighting is lost. The
  " following code makes sure the highlighting is refreshed afterwards.
  autocmd BufReadPost * unlet! b:easytags_last_highlighted
augroup END

" }}}1

" Make sure the plug-in is only loaded once.
let g:loaded_easytags = 1

" vim: ts=2 sw=2 et