From d4d78e4ae7d25e5813949cedf44b6792f613fa27 Mon Sep 17 00:00:00 2001
From: Jake Spurlock <whyisjake@git.wordpress.org>
Date: Tue, 9 Jun 2020 19:45:27 +0000
Subject: [PATCH] Cache API: Introduce `wp_cache_get_multi()`.

Many caching backend have support for multiple gets in a single request. This brings that support to core, with a compatability fallback that will loop over requests if needed.

Fixes: #20875.
Props: nacin, tollmanz, wonderboymusic, ryan, jeremyfelt, spacedmonkey, boonebgorges, dd32, rmccue, ocean90, jipmoors, johnjamesjacoby, tillkruess, donmhico, davidbaumwald, SergeyBiryukov, whyisjake.



git-svn-id: https://develop.svn.wordpress.org/trunk@47938 602fd350-edb4-49c9-b593-d223f7449a82
---
 src/wp-includes/cache.php                 | 18 ++++++++++++++++++
 src/wp-includes/class-wp-object-cache.php | 21 +++++++++++++++++++++
 src/wp-includes/load.php                  |  2 ++
 tests/phpunit/tests/cache.php             | 19 +++++++++++++++++++
 tests/phpunit/tests/pluggable.php         |  5 +++++
 5 files changed, 65 insertions(+)

diff --git a/src/wp-includes/cache.php b/src/wp-includes/cache.php
index 9957235873..23c5883ec0 100644
--- a/src/wp-includes/cache.php
+++ b/src/wp-includes/cache.php
@@ -126,6 +126,24 @@ function wp_cache_get( $key, $group = '', $force = false, &$found = null ) {
 	return $wp_object_cache->get( $key, $group, $force, $found );
 }
 
+/**
+ * Gets multiple values from cache in one call.
+ *
+ * @since 5.5.0
+ * @see WP_Object_Cache::get_multiple()
+ *
+ * @param array       $keys   Array of keys to get from group.
+ * @param string      $group  Optional. Where the cache contents are grouped. Default empty.
+ * @param bool        $force  Optional. Whether to force an update of the local cache from the persistent
+ *                            cache. Default false.
+ * @return array|bool Array of values.
+ */
+function wp_cache_get_multiple( $keys, $group = '', $force = false ) {
+	global $wp_object_cache;
+
+	return $wp_object_cache->get_multiple( $keys, $group, $force );
+}
+
 /**
  * Increment numeric cache item's value
  *
diff --git a/src/wp-includes/class-wp-object-cache.php b/src/wp-includes/class-wp-object-cache.php
index 428e453631..7a64cc4784 100644
--- a/src/wp-includes/class-wp-object-cache.php
+++ b/src/wp-includes/class-wp-object-cache.php
@@ -302,6 +302,27 @@ class WP_Object_Cache {
 		return false;
 	}
 
+	/**
+	 * Retrieves multiple values from the cache.
+	 *
+	 * @since  5.5.0
+	 *
+	 * @param array $keys        Array of keys to fetch.
+	 * @param bool  $force       Optional. Unused. Whether to force a refetch rather than relying on the local
+	 *                           cache. Default false.
+	 *
+	 * @return array Array of values organized into groups.
+	 */
+	public function get_multiple( $keys, $group = 'default', $force = false ) {
+		$values = array();
+
+		foreach ( $keys as $key ) {
+			$values[ $key ] = $this->get( $key, $group, $force );
+		}
+
+		return $values;
+	}
+
 	/**
 	 * Increments numeric cache item's value.
 	 *
diff --git a/src/wp-includes/load.php b/src/wp-includes/load.php
index 2ce982af2c..9023932e94 100644
--- a/src/wp-includes/load.php
+++ b/src/wp-includes/load.php
@@ -628,6 +628,8 @@ function wp_start_object_cache() {
 		require_once ABSPATH . WPINC . '/cache.php';
 	}
 
+	require_once( ABSPATH . WPINC . '/cache-compat.php' );
+
 	/*
 	 * If cache supports reset, reset instead of init if already
 	 * initialized. Reset signals to the cache that global IDs
diff --git a/tests/phpunit/tests/cache.php b/tests/phpunit/tests/cache.php
index a9534f875c..652df1c856 100644
--- a/tests/phpunit/tests/cache.php
+++ b/tests/phpunit/tests/cache.php
@@ -315,4 +315,23 @@ class Tests_Cache extends WP_UnitTestCase {
 		// Make sure $fake_key is not stored.
 		$this->assertFalse( wp_cache_get( $fake_key ) );
 	}
+
+	/**
+	 * @ticket 20875
+	 */
+	public function test_get_multiple() {
+		wp_cache_set( 'foo1', 'bar', 'group1' );
+		wp_cache_set( 'foo2', 'bar', 'group1' );
+		wp_cache_set( 'foo1', 'bar', 'group2' );
+
+		$found = wp_cache_get_multiple( array( 'foo1', 'foo2', 'foo3', ), 'group1' );
+
+		$expected = array(
+			'foo1' => 'bar',
+			'foo2' => 'bar',
+			'foo3' => false,
+		);
+
+		$this->assertSame( $expected, $found );
+	}
 }
diff --git a/tests/phpunit/tests/pluggable.php b/tests/phpunit/tests/pluggable.php
index 73ca7de806..879f31151d 100644
--- a/tests/phpunit/tests/pluggable.php
+++ b/tests/phpunit/tests/pluggable.php
@@ -290,6 +290,11 @@ class Tests_Pluggable extends WP_UnitTestCase {
 						'force' => false,
 						'found' => null,
 					),
+					'wp_cache_get_multiple'              => array(
+						'keys',
+						'group' => '',
+						'force' => false,
+					),
 					'wp_cache_incr'                      => array(
 						'key',
 						'offset' => 1,