From 56eaf3733fecbf01553e7e978054370071402551 Mon Sep 17 00:00:00 2001
From: Bailey Ling <bling@live.ca>
Date: Wed, 4 Sep 2013 19:53:04 +0000
Subject: [PATCH] add support to show tabline based on minimum buffer count
 (#220).

---
 autoload/airline/extensions/tabline.vim | 58 +++++++++++++++++++------
 doc/airline.txt                         |  3 ++
 2 files changed, 48 insertions(+), 13 deletions(-)

diff --git a/autoload/airline/extensions/tabline.vim b/autoload/airline/extensions/tabline.vim
index 12188cd2..53d9a737 100644
--- a/autoload/airline/extensions/tabline.vim
+++ b/autoload/airline/extensions/tabline.vim
@@ -16,13 +16,22 @@ let s:builder_context = {
       \ 'right_alt_sep' : get(g:, 'airline#extensions#tabline#right_alt_sep', g:airline_right_alt_sep),
       \ }
 
+let s:buf_min_count = get(g:, 'airline#extensions#tabline#buffer_min_count', 0)
+let s:buf_len = 0
+
 function! airline#extensions#tabline#init(ext)
   if has('gui_running')
     set guioptions-=e
   endif
-  set showtabline=2
+
   set tabline=%!airline#extensions#tabline#get()
 
+  if s:buf_min_count <= 0
+    set showtabline=2
+  else
+    autocmd CursorMoved * call <sid>cursormove()
+  endif
+
   call a:ext.add_theme_func('airline#extensions#tabline#load_theme')
 endfunction
 
@@ -40,6 +49,19 @@ function! airline#extensions#tabline#load_theme(palette)
   call airline#highlighter#exec('airline_tabmod', l:tabmod)
 endfunction
 
+function! s:cursormove()
+  let c = len(s:get_buffer_list())
+  if c > s:buf_min_count
+    if &showtabline != 2
+      set showtabline=2
+    endif
+  else
+    if &showtabline != 0
+      set showtabline=0
+    endif
+  endif
+endfunction
+
 function! airline#extensions#tabline#get()
   if tabpagenr('$') == 1
     return s:get_buffers()
@@ -75,8 +97,8 @@ function! airline#extensions#tabline#get_buffer_name(nr)
   return _
 endfunction
 
-function! s:get_buffers()
-  let b = airline#builder#new(s:builder_context)
+function! s:get_buffer_list()
+  let buffers = []
   let cur = bufnr('%')
   for nr in range(1, bufnr('$'))
     if buflisted(nr) && bufexists(nr)
@@ -85,18 +107,28 @@ function! s:get_buffers()
           continue
         endif
       endfor
-      if cur == nr
-        if g:airline_detect_modified && getbufvar(nr, '&modified')
-          let group = 'airline_tabmod'
-        else
-          let group = 'airline_tabsel'
-        endif
-      else
-        let group = 'airline_tab'
-      endif
-      call b.add_section(group, '%( %{airline#extensions#tabline#get_buffer_name('.nr.')} %)')
+      call add(buffers, nr)
     endif
   endfor
+  return buffers
+endfunction
+
+function! s:get_buffers()
+  let b = airline#builder#new(s:builder_context)
+  let cur = bufnr('%')
+  for nr in s:get_buffer_list()
+    if cur == nr
+      if g:airline_detect_modified && getbufvar(nr, '&modified')
+        let group = 'airline_tabmod'
+      else
+        let group = 'airline_tabsel'
+      endif
+    else
+      let group = 'airline_tab'
+    endif
+    call b.add_section(group, '%( %{airline#extensions#tabline#get_buffer_name('.nr.')} %)')
+  endfor
+
   call b.add_section('airline_tabfill', '')
   call b.split()
   call b.add_section('airline_tabtype', ' buffers ')
diff --git a/doc/airline.txt b/doc/airline.txt
index abe8ce0e..db39877e 100644
--- a/doc/airline.txt
+++ b/doc/airline.txt
@@ -312,6 +312,9 @@ virtualenv <https://github.com/jmcantrell/vim-virtualenv>
 * configure how buffer numbers should be formatted with |printf|. >
   let g:airline#extensions#tabline#buffer_nr_format = '%s: '
 <
+* configure the minimum number of buffers needed to show the tabline. >
+  let g:airline#extensions#tabline#buffer_min_count = 0
+<
 * configure separators for the tabline only. >
   let g:airline#extensions#tabline#left_sep = ''
   let g:airline#extensions#tabline#left_alt_sep = ''