From 4a769dbf5f683924a8ee3915701d7b96a4086007 Mon Sep 17 00:00:00 2001
From: John Firebaugh <john.firebaugh@gmail.com>
Date: Fri, 24 Jan 2014 17:17:41 -0800
Subject: [PATCH] Optimize Post#{next,previous}

Use object equality for comparisons rather than Comparable#==,
which in turn uses Post#<=>, which is slow.

This yielded a 3x performance improvement for `jekyll build`
on a large site (1m6.467s -> 0m19.532s).
---
 lib/jekyll/post.rb | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/lib/jekyll/post.rb b/lib/jekyll/post.rb
index 49214615..edc5caae 100644
--- a/lib/jekyll/post.rb
+++ b/lib/jekyll/post.rb
@@ -271,8 +271,7 @@ module Jekyll
     end
 
     def next
-      pos = self.site.posts.index(self)
-
+      pos = self.site.posts.index {|post| post.equal?(self) }
       if pos && pos < self.site.posts.length-1
         self.site.posts[pos+1]
       else
@@ -281,7 +280,7 @@ module Jekyll
     end
 
     def previous
-      pos = self.site.posts.index(self)
+      pos = self.site.posts.index {|post| post.equal?(self) }
       if pos && pos > 0
         self.site.posts[pos-1]
       else