From 670687fae0b9d1d26cf0a0bdb146fb6f08440bfa Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aschulz@wikimedia.org>
Date: Mon, 8 Jul 2019 12:12:16 -0700
Subject: [PATCH] objectcache: add IStoreKeyEncoder interface for key
 generation helper methods

If a key is stored in both BagOStuff and WANObjectCache, it useful to have
one common method for generating the cache and storage keys.

Change-Id: I8b77651746a55e8a98a79db298226e334d15a494
---
 autoload.php                                  |  1 +
 includes/libs/objectcache/BagOStuff.php       |  2 +-
 .../libs/objectcache/IStoreKeyEncoder.php     | 27 +++++++++++++++++++
 includes/libs/objectcache/WANObjectCache.php  |  2 +-
 4 files changed, 30 insertions(+), 2 deletions(-)
 create mode 100644 includes/libs/objectcache/IStoreKeyEncoder.php

diff --git a/autoload.php b/autoload.php
index 5eadf79b80..218c244a53 100644
--- a/autoload.php
+++ b/autoload.php
@@ -659,6 +659,7 @@ $wgAutoloadLocalClasses = [
 	'IP' => __DIR__ . '/includes/libs/IP.php',
 	'IPTC' => __DIR__ . '/includes/media/IPTC.php',
 	'IRCColourfulRCFeedFormatter' => __DIR__ . '/includes/rcfeed/IRCColourfulRCFeedFormatter.php',
+	'IStoreKeyEncoder' => __DIR__ . '/includes/libs/objectcache/IStoreKeyEncoder.php',
 	'IcuCollation' => __DIR__ . '/includes/collation/IcuCollation.php',
 	'IdentityCollation' => __DIR__ . '/includes/collation/IdentityCollation.php',
 	'ImageBuilder' => __DIR__ . '/maintenance/rebuildImages.php',
diff --git a/includes/libs/objectcache/BagOStuff.php b/includes/libs/objectcache/BagOStuff.php
index 7759947ee0..d7137d5679 100644
--- a/includes/libs/objectcache/BagOStuff.php
+++ b/includes/libs/objectcache/BagOStuff.php
@@ -61,7 +61,7 @@ use Wikimedia\WaitConditionLoop;
  *
  * @ingroup Cache
  */
-abstract class BagOStuff implements IExpiringStore, LoggerAwareInterface {
+abstract class BagOStuff implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInterface {
 	/** @var array[] Lock tracking */
 	protected $locks = [];
 	/** @var int ERR_* class constant */
diff --git a/includes/libs/objectcache/IStoreKeyEncoder.php b/includes/libs/objectcache/IStoreKeyEncoder.php
new file mode 100644
index 0000000000..da0686ea0c
--- /dev/null
+++ b/includes/libs/objectcache/IStoreKeyEncoder.php
@@ -0,0 +1,27 @@
+<?php
+
+/**
+ * Generic interface for object stores with key encoding methods.
+ *
+ * @ingroup Cache
+ * @since 1.34
+ */
+interface IStoreKeyEncoder {
+	/**
+	 * Make a global cache key.
+	 *
+	 * @param string $class Key class
+	 * @param string|null $component [optional] Key component (starting with a key collection name)
+	 * @return string Colon-delimited list of $keyspace followed by escaped components of $args
+	 */
+	public function makeGlobalKey( $class, $component = null );
+
+	/**
+	 * Make a cache key, scoped to this instance's keyspace.
+	 *
+	 * @param string $class Key class
+	 * @param string|null $component [optional] Key component (starting with a key collection name)
+	 * @return string Colon-delimited list of $keyspace followed by escaped components of $args
+	 */
+	public function makeKey( $class, $component = null );
+}
diff --git a/includes/libs/objectcache/WANObjectCache.php b/includes/libs/objectcache/WANObjectCache.php
index 1d8662a3c8..2487920ca6 100644
--- a/includes/libs/objectcache/WANObjectCache.php
+++ b/includes/libs/objectcache/WANObjectCache.php
@@ -113,7 +113,7 @@ use Psr\Log\NullLogger;
  * @ingroup Cache
  * @since 1.26
  */
-class WANObjectCache implements IExpiringStore, LoggerAwareInterface {
+class WANObjectCache implements IExpiringStore, IStoreKeyEncoder, LoggerAwareInterface {
 	/** @var BagOStuff The local datacenter cache */
 	protected $cache;
 	/** @var MapCacheLRU[] Map of group PHP instance caches */
-- 
2.20.1