From 6ab0098cedd35bc3edee69da8d57e14d98355104 Mon Sep 17 00:00:00 2001
From: Christian Brabandt <cb@256bit.org>
Date: Tue, 27 Jun 2017 13:52:48 +0200
Subject: [PATCH] Ale: Cache Warning and Errors

should provide some better performance
---
 autoload/airline/extensions/ale.vim | 41 ++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 12 deletions(-)

diff --git a/autoload/airline/extensions/ale.vim b/autoload/airline/extensions/ale.vim
index 062ef1d..a18d164 100644
--- a/autoload/airline/extensions/ale.vim
+++ b/autoload/airline/extensions/ale.vim
@@ -4,29 +4,46 @@
 let s:error_symbol = get(g:, 'airline#extensions#ale#error_symbol', 'E:')
 let s:warning_symbol = get(g:, 'airline#extensions#ale#warning_symbol', 'W:')
 
+function! s:airline_ale_count(cnt, symbol)
+  return a:cnt ? a:symbol. a:cnt : ''
+endfunction
+
 function! airline#extensions#ale#get(type)
   if !exists(':ALELint')
     return ''
   endif
 
-  let l:is_err = a:type ==# 'error'
-  let l:counts = ale#statusline#Count(bufnr(''))
-  let l:symbol = l:is_err ? s:error_symbol : s:warning_symbol
+  let is_err = a:type ==# 'error'
+  let symbol = is_err ? s:error_symbol : s:warning_symbol
 
-  if type(l:counts) == type({}) && has_key(l:counts, 'error')
+  if !exists('b:airline_extensions_ale_dict')
+    let b:airline_extensions_ale_dict = {}
+    let b:airline_extensions_ale_dict.error  = 0
+    let b:airline_extensions_ale_dict.warning = 0
+    let b:airline_extensions_ale_dict.change = 0
+  endif
+
+  if b:airline_extensions_ale_dict.change == b:changedtick
+    return s:airline_ale_count(b:airline_extensions_ale_dict[a:type], symbol)
+  endif
+
+  let is_err = a:type ==# 'error'
+  let counts = ale#statusline#Count(bufnr(''))
+  let symbol = is_err ? s:error_symbol : s:warning_symbol
+
+  if type(counts) == type({}) && has_key(counts, 'error')
     " Use the current Dictionary format.
-    let l:errors = l:counts.error + l:counts.style_error
-    let l:num = l:is_err ? l:errors : l:counts.total - l:errors
+    let errors = counts.error + counts.style_error
+    let num = is_err ? errors : counts.total - errors
   else
     " Use the old List format.
-    let l:num = l:is_err ? l:counts[0] : l:counts[1]
+    let num = is_err ? counts[0] : counts[1]
   endif
 
-  if l:num == 0
-    return ''
-  else
-    return l:symbol . l:num
-  endif
+  let b:airline_extensions_ale_dict[a:type] = num
+  let b:airline_extensions_ale_dict['change'] = b:changedtick
+
+  return s:airline_ale_count(num, symbol)
 endfunction
 
 function! airline#extensions#ale#get_warning()