Implement cache feature

autoload/neosnippet/parser.vim

@@ -35,7 +35,17 @@ function! neosnippet#parser#_parse(snippet_file) "{{{
     return {}
   endif
 
-  return s:parse(a:snippet_file)
+  let cache_dir = neosnippet#variables#data_dir()
+  if s:Cache.check_old_cache(cache_dir, a:snippet_file)
+    let snippets = s:parse(a:snippet_file)
+    if len(snippets) > 5
+      call s:Cache.writefile(cache_dir, a:snippet_file, [string(snippets)])
+    endif
+  else
+    sandbox let snippets = eval(s:Cache.readfile(cache_dir, a:snippet_file)[0])
+  endif
+
+  return snippets
 endfunction"}}}
 
 function! s:parse(snippet_file) "{{{

autoload/neosnippet/variables.vim

@@ -73,6 +73,17 @@ function! neosnippet#variables#runtime_dir() "{{{
 
   return s:runtime_dir
 endfunction"}}}
+function! neosnippet#variables#data_dir() "{{{
+  let g:neosnippet#data_directory =
+        \ substitute(fnamemodify(get(
+        \   g:, 'neosnippet#data_directory', '~/.cache/neosnippet'),
+        \  ':p'), '\\', '/', 'g')
+  if !isdirectory(g:neosnippet#data_directory)
+    call mkdir(g:neosnippet#data_directory, 'p')
+  endif
+
+  return g:neosnippet#data_directory
+endfunction"}}}
 
 let &cpo = s:save_cpo
 unlet s:save_cpo