detect whether quickfix or location list is open.

autoload/airline/extensions/quickfix.vim

@@ -0,0 +1,37 @@
+" MIT License. Copyright (c) 2013 Bailey Ling.
+" vim: et ts=2 sts=2 sw=2
+
+let g:airline#extensions#quickfix#quickfix_text = 'Quickfix'
+let g:airline#extensions#quickfix#location_text = 'Location'
+
+function! airline#extensions#quickfix#apply(...)
+  if &buftype == 'quickfix'
+    let w:airline_section_a = s:get_text()
+    let w:airline_section_b = '%{get(w:, "quickfix_title", "")}'
+    let w:airline_section_c = ''
+    let w:airline_section_x = ''
+  endif
+endfunction
+
+function! airline#extensions#quickfix#init(ext)
+  call a:ext.add_statusline_func('airline#extensions#quickfix#apply')
+endfunction
+
+function! s:get_text()
+  redir => buffers
+  silent ls
+  redir END
+
+  let nr = bufnr('%')
+  for buf in split(buffers, '\n')
+    if match(buf, '\v^\s+'.nr) > -1
+      if match(buf, '\[Quickfix List\]') > -1
+        return g:airline#extensions#quickfix#quickfix_text
+      else
+        return g:airline#extensions#quickfix#location_text
+      endif
+    endif
+  endfor
+  return ''
+endfunction
+