1 files changed, 91 insertions, 0 deletions
diff --git a/autoload/vimtex/paths.vim b/autoload/vimtex/paths.vim
new file mode 100644
index 00000000..0d308ed8
--- /dev/null
+++ b/autoload/vimtex/paths.vim
@@ -0,0 +1,91 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'latex') == -1
+
+" vimtex - LaTeX plugin for Vim
+"
+" Maintainer: Karl Yngve Lervåg
+" Email:      karl.yngve@gmail.com
+"
+
+function! vimtex#paths#pushd(path) abort " {{{1
+  if empty(a:path) || getcwd() ==# fnamemodify(a:path, ':p')
+    let s:qpath += ['']
+  else
+    let s:qpath += [getcwd()]
+    execute s:cd fnameescape(a:path)
+  endif
+endfunction
+
+" }}}1
+function! vimtex#paths#popd() abort " {{{1
+  let l:path = remove(s:qpath, -1)
+  if !empty(l:path)
+    execute s:cd fnameescape(l:path)
+  endif
+endfunction
+
+" }}}1
+
+function! vimtex#paths#is_abs(path) abort " {{{1
+  return a:path =~# s:re_abs
+endfunction
+
+" }}}1
+
+function! vimtex#paths#shorten_relative(path) abort " {{{1
+  " Input: An absolute path
+  " Output: Relative path with respect to the vimtex root, path relative to
+  "         vimtex root (unless absolute path is shorter)
+
+  let l:relative = vimtex#paths#relative(a:path, b:vimtex.root)
+  return strlen(l:relative) < strlen(a:path)
+        \ ? l:relative : a:path
+endfunction
+
+" }}}1
+function! vimtex#paths#relative(path, current) abort " {{{1
+  " Note: This algorithm is based on the one presented by @Offirmo at SO,
+  "       http://stackoverflow.com/a/12498485/51634
+
+  let l:target = simplify(substitute(a:path, '\\', '/', 'g'))
+  let l:common = simplify(substitute(a:current, '\\', '/', 'g'))
+
+  " This only works on absolute paths
+  if !vimtex#paths#is_abs(l:target)
+    return substitute(a:path, '^\.\/', '', '')
+  endif
+
+  let l:tries = 50
+  let l:result = ''
+  while stridx(l:target, l:common) != 0 && l:tries > 0
+    let l:common = fnamemodify(l:common, ':h')
+    let l:result = empty(l:result) ? '..' : '../' . l:result
+    let l:tries -= 1
+  endwhile
+
+  if l:tries == 0 | return a:path | endif
+
+  if l:common ==# '/'
+    let l:result .= '/'
+  endif
+
+  let l:forward = strpart(l:target, strlen(l:common))
+  if !empty(l:forward)
+    let l:result = empty(l:result)
+          \ ? l:forward[1:]
+          \ : l:result . l:forward
+  endif
+
+  return l:result
+endfunction
+
+" }}}1
+
+
+let s:cd = exists('*haslocaldir') && haslocaldir()
+      \ ? 'lcd'
+      \ : exists(':tcd') && haslocaldir(-1) ? 'tcd' : 'cd'
+let s:qpath = get(s:, 'qpath', [])
+
+let s:re_abs = has('win32') ? '^[A-Z]:[\\/]' : '^/'
+
+endif