From b30f495345fa14f9fdea24cd44e374a2144cfa5c Mon Sep 17 00:00:00 2001
From: Daniele Alessandri <suppakilla@gmail.com>
Date: Sat, 20 Aug 2011 18:07:42 +0200
Subject: [PATCH] Change how the hash of a node is retrieved in the
 hashring-based distributor.

Now classes that extend Predis\Distribution\HashRing can override how the hash
of a node is retrieved in order to implement different kind of distribution
strategies while reusing the base algorithm.
---
 lib/Predis/Distribution/HashRing.php       | 6 +++++-
 lib/Predis/Distribution/KetamaPureRing.php | 2 +-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/lib/Predis/Distribution/HashRing.php b/lib/Predis/Distribution/HashRing.php
index ddd11c14..53e0099e 100644
--- a/lib/Predis/Distribution/HashRing.php
+++ b/lib/Predis/Distribution/HashRing.php
@@ -80,7 +80,7 @@ class HashRing implements IDistributionStrategy {
 
     protected function addNodeToRing(&$ring, $node, $totalNodes, $replicas, $weightRatio) {
         $nodeObject = $node['object'];
-        $nodeHash = (string) $nodeObject;
+        $nodeHash = $this->getNodeHash($nodeObject);
         $replicas = (int) round($weightRatio * $totalNodes * $replicas);
         for ($i = 0; $i < $replicas; $i++) {
             $key = crc32("$nodeHash:$i");
@@ -88,6 +88,10 @@ class HashRing implements IDistributionStrategy {
         }
     }
 
+    protected function getNodeHash($nodeObject) {
+        return (string) $nodeObject;
+    }
+
     public function generateKey($value) {
         return crc32($value);
     }
diff --git a/lib/Predis/Distribution/KetamaPureRing.php b/lib/Predis/Distribution/KetamaPureRing.php
index 48b975a1..5439531d 100644
--- a/lib/Predis/Distribution/KetamaPureRing.php
+++ b/lib/Predis/Distribution/KetamaPureRing.php
@@ -11,7 +11,7 @@ class KetamaPureRing extends HashRing {
 
     protected function addNodeToRing(&$ring, $node, $totalNodes, $replicas, $weightRatio) {
         $nodeObject = $node['object'];
-        $nodeHash = (string) $nodeObject;
+        $nodeHash = $this->getNodeHash($nodeObject);
         $replicas = (int) floor($weightRatio * $totalNodes * ($replicas / 4));
         for ($i = 0; $i < $replicas; $i++) {
             $unpackedDigest = unpack('V4', md5("$nodeHash-$i", true));