lib/Twig/lib/Twig/Environment.php
public function setCache($cache)
    {
        if (is_string($cache)) {
            $this->originalCache = $cache;
            $this->cache = new Twig_Cache_Filesystem($cache);
        } elseif (false === $cache) {
            $this->originalCache = $cache;
            $this->cache = new Twig_Cache_Null();
        } elseif (null === $cache) {
            @trigger_error('Using "null" as the cache strategy is deprecated since version 1.23 and will be removed in Twig 2.0.', E_USER_DEPRECATED);
            $this->originalCache = false;
            $this->cache = new Twig_Cache_Null();
        } elseif ($cache instanceof Twig_CacheInterface) {
            $this->originalCache = $this->cache = $cache;
        } else {
            throw new LogicException(sprintf('Cache can only be a string, false, or a Twig_CacheInterface implementation.'));
        }
    }
public function setCache($cache)
    {
        if (is_string($cache)) {
            $this->originalCache = $cache;
            $this->cache = new Twig_Cache_Filesystem($cache);
        } elseif (false === $cache) {
            $this->originalCache = $cache;
            $this->cache = new Twig_Cache_Null();
        } elseif (null === $cache) {
            @trigger_error('Using "null" as the cache strategy is deprecated since version 1.23 and will be removed in Twig 2.0.', E_USER_DEPRECATED);
            $this->originalCache = false;
            $this->cache = new Twig_Cache_Null();
        } elseif ($cache instanceof Twig_CacheInterface) {
            $this->originalCache = $this->cache = $cache;
        } else {
            throw new LogicException(sprintf('Cache can only be a string, false, or a Twig_CacheInterface implementation.'));
        }
    }
Sets the current cache implementation.

@param Twig_CacheInterface|string|false $cache A Twig_CacheInterface implementation,
an absolute path to the compiled templates,
or false to disable cache