From ca2eaf13e48276ab2f4ed84fc797e3e4c1b57fcb Mon Sep 17 00:00:00 2001
From: Aaron <aschulz@wikimedia.org>
Date: Thu, 30 Aug 2012 12:47:19 -0700
Subject: [PATCH] [FileBackend] Improved stat caching by reducing cache
 salting.

Change-Id: Ieec6515fcf1c2f147b52eceec1f6c55a681115c5
---
 includes/filebackend/FileBackendStore.php | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/includes/filebackend/FileBackendStore.php b/includes/filebackend/FileBackendStore.php
index 9bec145d29..d53f7b3603 100644
--- a/includes/filebackend/FileBackendStore.php
+++ b/includes/filebackend/FileBackendStore.php
@@ -105,7 +105,9 @@ abstract class FileBackendStore extends FileBackend {
 		} else {
 			$status = $this->doCreateInternal( $params );
 			$this->clearCache( array( $params['dst'] ) );
-			$this->deleteFileCache( $params['dst'] ); // persistent cache
+			if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
+				$this->deleteFileCache( $params['dst'] ); // persistent cache
+			}
 		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
@@ -141,7 +143,9 @@ abstract class FileBackendStore extends FileBackend {
 		} else {
 			$status = $this->doStoreInternal( $params );
 			$this->clearCache( array( $params['dst'] ) );
-			$this->deleteFileCache( $params['dst'] ); // persistent cache
+			if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
+				$this->deleteFileCache( $params['dst'] ); // persistent cache
+			}
 		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
@@ -173,7 +177,9 @@ abstract class FileBackendStore extends FileBackend {
 		wfProfileIn( __METHOD__ . '-' . $this->name );
 		$status = $this->doCopyInternal( $params );
 		$this->clearCache( array( $params['dst'] ) );
-		$this->deleteFileCache( $params['dst'] ); // persistent cache
+		if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
+			$this->deleteFileCache( $params['dst'] ); // persistent cache
+		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
 		return $status;
@@ -235,7 +241,9 @@ abstract class FileBackendStore extends FileBackend {
 		$status = $this->doMoveInternal( $params );
 		$this->clearCache( array( $params['src'], $params['dst'] ) );
 		$this->deleteFileCache( $params['src'] ); // persistent cache
-		$this->deleteFileCache( $params['dst'] ); // persistent cache
+		if ( !empty( $params['overwrite'] ) ) { // file possibly mutated
+			$this->deleteFileCache( $params['dst'] ); // persistent cache
+		}
 		wfProfileOut( __METHOD__ . '-' . $this->name );
 		wfProfileOut( __METHOD__ );
 		return $status;
@@ -1460,7 +1468,9 @@ abstract class FileBackendStore extends FileBackend {
 	}
 
 	/**
-	 * Set the cached stat info for a file path
+	 * Set the cached stat info for a file path.
+	 * Negatives (404s) are not cached. By not caching negatives, we can skip cache
+	 * salting for the case when a file is created at a path were there was none before.
 	 *
 	 * @param $path string Storage path
 	 * @param $val mixed Information to cache
-- 
2.20.1