Move filetype.vim helper funcs into autoload

May as well, now that we've dropped support for versions of Vim that
don't have it.

1 files changed, 76 insertions, 0 deletions

diff --git a/vim/autoload/filetype.vim b/vim/autoload/filetype.vim
new file mode 100644
index 00000000..d1e4e3d7
--- /dev/null
+++ b/vim/autoload/filetype.vim
@@ -0,0 +1,76 @@
+" Helper function to run the 'filetypedetect' group on a file with its
+" extension stripped off
+function! filetype#StripRepeat() abort
+
+  " Check we have the fnameescape() function
+  if !exists('*fnameescape')
+    return
+  endif
+
+  " Expand the match result
+  let l:fn = expand('<afile>')
+
+  " Strip leading and trailing #hashes#
+  if l:fn =~# '^#\+.*#\+$'
+    let l:fn = substitute(l:fn, '^#\+\(.\+\)#\+$', '\1', '')
+
+  " Strip trailing tilde~
+  elseif l:fn =~# '\~$'
+    let l:fn = substitute(l:fn, '\~$', '', '')
+
+  " Strip generic .extension
+  else
+    let l:fn = expand('<afile>:r')
+  endif
+
+  " Re-run the group if there's anything left
+  if strlen(l:fn)
+    execute 'doautocmd filetypedetect BufRead ' . fnameescape(l:fn)
+  endif
+
+endfunction
+
+" Helper function to run the 'filetypedetect' group on a file in a temporary
+" sudoedit(8) directory, modifying it with an attempt to reverse the temporary
+" filename change
+function! filetype#SudoRepeat() abort
+
+  " Check we have the fnameescape() function
+  if !exists('*fnameescape')
+    return
+  endif
+
+  " Expand the match result
+  let l:fn = expand('<afile>')
+
+  " myfileXXQGS16A.conf: strip eight chars before final period
+  if l:fn =~# '/[^./]\+\w\{8}\.[^./]\+$'
+    let l:fr = expand('<afile>:r')
+    let l:fe = expand('<afile>:e')
+    let l:fn = strpart(l:fr, -8, strlen(l:fr)) . '.' . l:fe
+
+  " myfile.XXQGS16A: strip extension
+  elseif l:fn =~# '/[^./]\+\.\w\{8}$'
+    let l:fn = expand('<afile>:r')
+
+  " Unrecognised pattern; return, don't repeat
+  else
+    return
+  endif
+
+  " Re-run the group if there's anything left
+  if strlen(l:fn)
+    execute 'doautocmd filetypedetect BufRead ' . fnameescape(l:fn)
+  endif
+
+endfunction
+
+" Check whether the first line was changed and looks like a shebang, and if
+" so, re-run filetype detection
+function! filetype#CheckShebang() abort
+  if line('''[') == 1 && getline(1) =~# '^#!'
+    doautocmd filetypedetect BufRead
+  endif
+endfunction
+
+