From 21b128a89c66b73cb59cbc487b5395821a392be1 Mon Sep 17 00:00:00 2001
From: Fabien Potencier <fabien.potencier@gmail.com>
Date: Sat, 22 Aug 2015 14:42:57 +0200
Subject: [PATCH] optimized the filesystem loader

* added a cache for templates that do not exist
* sped up Filesystem::exists() by avoiding the creation of exceptions

same as d2b97b49f240efb453e75558f00e17ccb1d915c5 that was reverted because of a BC break
and same as what is in 2.0 (but in a BC way).
---
 lib/Twig/Loader/Filesystem.php | 34 +++++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/lib/Twig/Loader/Filesystem.php b/lib/Twig/Loader/Filesystem.php
index 818a461c58..a68876cee3 100644
--- a/lib/Twig/Loader/Filesystem.php
+++ b/lib/Twig/Loader/Filesystem.php
@@ -21,6 +21,7 @@ class Twig_Loader_Filesystem implements Twig_LoaderInterface, Twig_ExistsLoaderI
 
     protected $paths = array();
     protected $cache = array();
+    protected $errorCache = array();
 
     /**
      * Constructor.
@@ -87,7 +88,7 @@ public function setPaths($paths, $namespace = self::MAIN_NAMESPACE)
     public function addPath($path, $namespace = self::MAIN_NAMESPACE)
     {
         // invalidate the cache
-        $this->cache = array();
+        $this->cache = $this->errorCache = array();
 
         if (!is_dir($path)) {
             throw new Twig_Error_Loader(sprintf('The "%s" directory does not exist.', $path));
@@ -107,7 +108,7 @@ public function addPath($path, $namespace = self::MAIN_NAMESPACE)
     public function prependPath($path, $namespace = self::MAIN_NAMESPACE)
     {
         // invalidate the cache
-        $this->cache = array();
+        $this->cache = $this->errorCache = array();
 
         if (!is_dir($path)) {
             throw new Twig_Error_Loader(sprintf('The "%s" directory does not exist.', $path));
@@ -150,9 +151,7 @@ public function exists($name)
         }
 
         try {
-            $this->findTemplate($name);
-
-            return true;
+            return false !== $this->findTemplate($name, false);
         } catch (Twig_Error_Loader $exception) {
             return false;
         }
@@ -168,18 +167,33 @@ public function isFresh($name, $time)
 
     protected function findTemplate($name)
     {
+        $throw = func_num_args() > 1 ? func_get_arg(1) : true;
         $name = $this->normalizeName($name);
 
         if (isset($this->cache[$name])) {
             return $this->cache[$name];
         }
 
+        if (isset($this->errorCache[$name])) {
+            if (!$throw) {
+                return false;
+            }
+
+            throw new Twig_Error_Loader($this->errorCache[$name]);
+        }
+
         $this->validateName($name);
 
         list($namespace, $shortname) = $this->parseName($name);
 
         if (!isset($this->paths[$namespace])) {
-            throw new Twig_Error_Loader(sprintf('There are no registered paths for namespace "%s".', $namespace));
+            $this->errorCache[$name] = sprintf('There are no registered paths for namespace "%s".', $namespace);
+
+            if (!$throw) {
+                return false;
+            }
+
+            throw new Twig_Error_Loader($this->errorCache[$name]);
         }
 
         foreach ($this->paths[$namespace] as $path) {
@@ -192,7 +206,13 @@ protected function findTemplate($name)
             }
         }
 
-        throw new Twig_Error_Loader(sprintf('Unable to find template "%s" (looked into: %s).', $name, implode(', ', $this->paths[$namespace])));
+        $this->errorCache[$name] = sprintf('Unable to find template "%s" (looked into: %s).', $name, implode(', ', $this->paths[$namespace]));
+
+        if (!$throw) {
+            return false;
+        }
+
+        throw new Twig_Error_Loader($this->errorCache[$name]);
     }
 
     protected function parseName($name, $default = self::MAIN_NAMESPACE)