extract buffer listing to its own file

autoload/airline/extensions/tabline/buflist.vim

@@ -0,0 +1,38 @@
+" MIT License. Copyright (c) 2013-2015 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+let s:excludes = get(g:, 'airline#extensions#tabline#excludes', [])
+
+function! airline#extensions#tabline#buflist#invalidate()
+  unlet! s:current_buffer_list
+endfunction
+
+function! airline#extensions#tabline#buflist#list()
+  if exists('s:current_buffer_list')
+    return s:current_buffer_list
+  endif
+
+  let buffers = []
+  let cur = bufnr('%')
+  for nr in range(1, bufnr('$'))
+    if buflisted(nr) && bufexists(nr)
+      let toadd = 1
+      for ex in s:excludes
+        if match(bufname(nr), ex) >= 0
+          let toadd = 0
+          break
+        endif
+      endfor
+      if getbufvar(nr, 'current_syntax') == 'qf'
+        let toadd = 0
+      endif
+      if toadd
+        call add(buffers, nr)
+      endif
+    endif
+  endfor
+
+  let s:current_buffer_list = buffers
+  return buffers
+endfunction
+