From 04c393ab073b96dbffbb89625103562aadeea3ec Mon Sep 17 00:00:00 2001
From: Jeroen Visser <jeroenvisser101@gmail.com>
Date: Mon, 21 Mar 2016 14:23:35 +0100
Subject: [PATCH] Use start_with? instead of Regex

Performance is increased by doing this:

  require 'benchmark'
  require 'tempfile'

  n = 50000
  test = File.expand_path(Tempfile.new('foo'))
  Benchmark.bm(20) do |x|
    x.report("Regex:") do
      n.times { test =~ /\A#{test}/ }
    end
    x.report("String#start_with?:") do
      n.times { test =~ test.start_with?(test) }
    end
  end

Benchmark result:
                             user     system      total        real
  Regex:                 0.440000   0.010000   0.450000 (  0.447357)
  String#start_with?:    0.000000   0.000000   0.000000 (  0.006313)
---
 lib/liquid/file_system.rb | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/liquid/file_system.rb b/lib/liquid/file_system.rb
index 8e71f44..bf7ce1a 100644
--- a/lib/liquid/file_system.rb
+++ b/lib/liquid/file_system.rb
@@ -65,7 +65,7 @@ module Liquid
         File.join(root, @pattern % template_path)
       end
 
-      raise FileSystemError, "Illegal template path '#{File.expand_path(full_path)}'" unless File.expand_path(full_path) =~ /\A#{File.expand_path(root)}/
+      raise FileSystemError, "Illegal template path '#{File.expand_path(full_path)}'" unless File.expand_path(full_path).start_with?(File.expand_path(root))
 
       full_path
     end