From: Aaron Schulz <aschulz@wikimedia.org>
Date: Sat, 3 Oct 2015 19:37:28 +0000 (-0700)
Subject: objectcache: Add BagOStuff::getWithSetCallback() convenience method
X-Git-Tag: 1.31.0-rc.0~9538^2
X-Git-Url: https://git.cyclocoop.org/%27.%24link.%27?a=commitdiff_plain;h=355ba8530ed923d23bba1b97e366dc0f906dd006;p=lhc%2Fweb%2Fwiklou.git

objectcache: Add BagOStuff::getWithSetCallback() convenience method

Change-Id: I9cc162ff1cc48c1c500f2999327bd18ba235bfd0
---

diff --git a/includes/libs/objectcache/BagOStuff.php b/includes/libs/objectcache/BagOStuff.php
index 31bffd4447..647d938919 100644
--- a/includes/libs/objectcache/BagOStuff.php
+++ b/includes/libs/objectcache/BagOStuff.php
@@ -87,6 +87,33 @@ abstract class BagOStuff implements LoggerAwareInterface {
 		$this->debugMode = $bool;
 	}
 
+	/**
+	 * Get an item with the given key, regenerating and setting it if not found
+	 *
+	 * If the callback returns false, then nothing is stored.
+	 *
+	 * @param string $key
+	 * @param int $ttl Time-to-live (seconds)
+	 * @param callable $callback Callback that derives the new value
+	 * @return mixed The cached value if found or the result of $callback otherwise
+	 * @since 1.27
+	 */
+	final public function getWithSetCallback( $key, $ttl, $callback ) {
+		$value = $this->get( $key );
+
+		if ( $value === false ) {
+			if ( !is_callable( $callback ) ) {
+				throw new InvalidArgumentException( "Invalid cache miss callback provided." );
+			}
+			$value = call_user_func( $callback );
+			if ( $value !== false ) {
+				$this->set( $key, $value, $ttl );
+			}
+		}
+
+		return $value;
+	}
+
 	/**
 	 * Get an item with the given key
 	 *
diff --git a/tests/phpunit/includes/objectcache/BagOStuffTest.php b/tests/phpunit/includes/objectcache/BagOStuffTest.php
index dbccd28a20..b9fe4903c4 100644
--- a/tests/phpunit/includes/objectcache/BagOStuffTest.php
+++ b/tests/phpunit/includes/objectcache/BagOStuffTest.php
@@ -120,6 +120,23 @@ class BagOStuffTest extends MediaWikiTestCase {
 		$this->assertEquals( $this->cache->get( $key ), $value );
 	}
 
+	/**
+	 * @covers BagOStuff::getWithSetCallback
+	 */
+	public function testGetWithSetCallback() {
+		$key = wfMemcKey( 'test' );
+		$value = $this->cache->getWithSetCallback(
+			$key,
+			30,
+			function () {
+				return 'hello kitty';
+			}
+		);
+
+		$this->assertEquals( 'hello kitty', $value );
+		$this->assertEquals( $value, $this->cache->get( $key ) );
+	}
+
 	/**
 	 * @covers BagOStuff::incr
 	 */