From e0d817b7f6a58875782f31bb025a9df5c3ac2a33 Mon Sep 17 00:00:00 2001
From: Timo Tijhof <krinklemail@gmail.com>
Date: Sat, 31 Aug 2019 22:38:42 +0100
Subject: [PATCH] objectcache: Optimise array_map in
 MemcachedBagOStuff::makeKey()

This can get called a lot on an average page load, optimise
a bit by using a referenced foreach iteration instead.

Using a simplified test case, I found this saves about 70% on PHP 7.2.
For 100 iterations, from ~1.5ms to ~0.4 ms.

```lang=php
$args = [ 'FooBar', 'thisthat', 4, 'foo', 12 ];
$left = 100;
foreach ($args as &$arg) {
    $arg = strtr( $arg, ' ', '_' );
    if ( strlen( $arg ) < $left || true ) {
        $arg = '#' . $arg;
    }
    $left--;
}
```

Change-Id: Ie779c4661306a6d3dc08c08671f1a36682ca1afb
---
 .../libs/objectcache/MemcachedBagOStuff.php   | 36 +++++++++----------
 1 file changed, 16 insertions(+), 20 deletions(-)

diff --git a/includes/libs/objectcache/MemcachedBagOStuff.php b/includes/libs/objectcache/MemcachedBagOStuff.php
index dc409315f8..40f283621d 100644
--- a/includes/libs/objectcache/MemcachedBagOStuff.php
+++ b/includes/libs/objectcache/MemcachedBagOStuff.php
@@ -49,29 +49,25 @@ abstract class MemcachedBagOStuff extends MediumSpecificBagOStuff {
 		// custom prefixes used by thing like WANObjectCache, limit to 205.
 		$charsLeft = 205 - strlen( $keyspace ) - count( $args );
 
-		$args = array_map(
-			function ( $arg ) use ( &$charsLeft ) {
-				$arg = strtr( $arg, ' ', '_' );
+		foreach ( $args as &$arg ) {
+			$arg = strtr( $arg, ' ', '_' );
 
-				// Make sure %, #, and non-ASCII chars are escaped
-				$arg = preg_replace_callback(
-					'/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
-					function ( $m ) {
-						return rawurlencode( $m[0] );
-					},
-					$arg
-				);
+			// Make sure %, #, and non-ASCII chars are escaped
+			$arg = preg_replace_callback(
+				'/[^\x21-\x22\x24\x26-\x39\x3b-\x7e]+/',
+				function ( $m ) {
+					return rawurlencode( $m[0] );
+				},
+				$arg
+			);
 
-				// 33 = 32 characters for the MD5 + 1 for the '#' prefix.
-				if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
-					$arg = '#' . md5( $arg );
-				}
+			// 33 = 32 characters for the MD5 + 1 for the '#' prefix.
+			if ( $charsLeft > 33 && strlen( $arg ) > $charsLeft ) {
+				$arg = '#' . md5( $arg );
+			}
 
-				$charsLeft -= strlen( $arg );
-				return $arg;
-			},
-			$args
-		);
+			$charsLeft -= strlen( $arg );
+		}
 
 		if ( $charsLeft < 0 ) {
 			return $keyspace . ':BagOStuff-long-key:##' . md5( implode( ':', $args ) );
-- 
2.20.1