Add OmniSharp extension to display server status

autoload/airline/extensions.vim

@@ -461,6 +461,11 @@ function! airline#extensions#load()
     call add(s:loaded_ext, 'dirvish')
   endif
 
+  if (get(g:, 'airline#extensions#omnisharp#enabled', 1) && get(g:, 'OmniSharp_loaded', 0))
+    call airline#extensions#omnisharp#init(s:ext)
+    call add(s:loaded_ext, 'omnisharp')
+  endif
+
 endfunction
 
 function! airline#extensions#get_loaded_extensions()

autoload/airline/extensions/omnisharp.vim

@@ -0,0 +1,45 @@
+" MIT License
+" Plugin: https://github.com/OmniSharp/omnisharp-vim
+" vim: et ts=2 sts=2 sw=2
+
+scriptencoding utf-8
+
+if !get(g:, 'OmniSharp_loaded', 0)
+  finish
+endif
+
+function! airline#extensions#omnisharp#server_status(...) abort
+  if !exists(':OmniSharpGotoDefinition') || !get(g:, 'OmniSharp_server_stdio', 0)
+    return ''
+  endif
+
+  let host = OmniSharp#GetHost(bufnr('%'))
+  if type(host.job) != v:t_dict || get(host.job, 'stopped')
+    return ''
+  endif
+
+  let sln = fnamemodify(host.sln_or_dir, ':t')
+
+  if get(host.job, 'loaded', 0)
+    return sln
+  endif
+
+  try
+    let projectsloaded = OmniSharp#project#CountLoaded()
+    let projectstotal = OmniSharp#project#CountTotal()
+  catch
+    " The CountLoaded and CountTotal functions are very new - catch the error
+    " when they don't exist
+    let projectsloaded = 0
+    let projectstotal = 0
+  endtry
+  return printf('%s(%d/%d)', sln, projectsloaded, projectstotal)
+endfunction
+
+function! airline#extensions#omnisharp#init(ext) abort
+  call airline#parts#define_function('omnisharp', 'airline#extensions#omnisharp#server_status')
+  augroup airline_omnisharp
+    autocmd!
+    autocmd User OmniSharpStarted,OmniSharpReady,OmniSharpStopped AirlineRefresh!
+  augroup END
+endfunction

autoload/airline/init.vim

@@ -178,6 +178,7 @@ function! airline#init#bootstrap()
   call airline#parts#define_text('grepper', '')
   call airline#parts#define_text('xkblayout', '')
   call airline#parts#define_text('keymap', '')
+  call airline#parts#define_text('omnisharp', '')
 
   unlet g:airline#init#bootstrapping
 endfunction
@@ -205,7 +206,7 @@ function! airline#init#sections()
     let g:airline_section_gutter = airline#section#create(['%='])
   endif
   if !exists('g:airline_section_x')
-    let g:airline_section_x = airline#section#create_right(['bookmark', 'tagbar', 'vista', 'gutentags', 'grepper', 'filetype'])
+    let g:airline_section_x = airline#section#create_right(['bookmark', 'tagbar', 'vista', 'gutentags', 'omnisharp', 'grepper', 'filetype'])
   endif
   if !exists('g:airline_section_y')
     let g:airline_section_y = airline#section#create_right(['ffenc'])