From 1ba93d9b77b06daba56b21ed4af13eff9c2beb8e Mon Sep 17 00:00:00 2001
From: Aaron Schulz <aaron@users.mediawiki.org>
Date: Sun, 2 Oct 2011 19:44:31 +0000
Subject: [PATCH] * Added isCacheWorthy() optimization (checks if the file
 exists, stale or not) * Made isCached() use process cache * Added
 MISS_TTL_SEC constant and tweaked MISS_FACTOR constant

---
 includes/cache/FileCacheBase.php     | 17 +++++++++++++----
 includes/cache/HTMLFileCache.php     |  6 +++---
 includes/cache/ResourceFileCache.php |  7 +++++--
 3 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/includes/cache/FileCacheBase.php b/includes/cache/FileCacheBase.php
index 1ed9546f93..e6be049335 100644
--- a/includes/cache/FileCacheBase.php
+++ b/includes/cache/FileCacheBase.php
@@ -10,9 +10,12 @@ abstract class FileCacheBase {
 	protected $mExt = 'cache';
 	protected $mFilePath;
 	protected $mUseGzip;
+	/* lazy loaded */
+	protected $mCached;
 
 	/* @TODO: configurable? */
-	const MISS_FACTOR = 10; // log 1 every MISS_FACTOR cache misses
+	const MISS_FACTOR = 15; // log 1 every MISS_FACTOR cache misses
+	const MISS_TTL_SEC = 3600; // how many seconds ago is "recent"
 
 	protected function __construct() {
 		global $wgUseGzip;
@@ -70,7 +73,10 @@ abstract class FileCacheBase {
 	 * @return bool
 	 */
 	public function isCached() {
-		return file_exists( $this->cachePath() );
+		if ( $this->mCached === null ) {
+			$this->mCached = file_exists( $this->cachePath() );
+		}
+		return $this->mCached;
 	}
 
 	/**
@@ -142,9 +148,11 @@ abstract class FileCacheBase {
 
 		$this->checkCacheDirs(); // build parent dir
 		if ( !file_put_contents( $this->cachePath(), $text, LOCK_EX ) ) {
+			$this->mCached = null;
 			return false;
 		}
 
+		$this->mCached = true;
 		return $text;
 	}
 
@@ -156,6 +164,7 @@ abstract class FileCacheBase {
 		wfSuppressWarnings();
 		unlink( $this->cachePath() );
 		wfRestoreWarnings();
+		$this->mCached = false;
 	}
 
 	/**
@@ -216,12 +225,12 @@ abstract class FileCacheBase {
 			if ( $wgMemc->get( $key ) ) {
 				return; // possibly the same user
 			}
-			$wgMemc->set( $key, 1, 3600 );
+			$wgMemc->set( $key, 1, self::MISS_TTL_SEC );
 
 			# Increment the number of cache misses...
 			$key = $this->cacheMissKey();
 			if ( $wgMemc->get( $key ) === false ) {
-				$wgMemc->set( $key, 1, 3600 );
+				$wgMemc->set( $key, 1, self::MISS_TTL_SEC );
 			} else {
 				$wgMemc->incr( $key );
 			}
diff --git a/includes/cache/HTMLFileCache.php b/includes/cache/HTMLFileCache.php
index ac63a2a5b3..532850a596 100644
--- a/includes/cache/HTMLFileCache.php
+++ b/includes/cache/HTMLFileCache.php
@@ -75,14 +75,14 @@ class HTMLFileCache extends FileCacheBase {
 		// Get all query values
 		$queryVals = $context->getRequest()->getValues();
 		foreach ( $queryVals as $query => $val ) {
-			if ( $query == 'title' || $query == 'curid' ) {
+			if ( $query === 'title' || $query === 'curid' ) {
 				continue; // note: curid sets title
 			// Normal page view in query form can have action=view.
 			// Raw hits for pages also stored, like .css pages for example.
-			} elseif ( $query == 'action' && in_array( $val, self::cacheablePageActions() ) ) {
+			} elseif ( $query === 'action' && in_array( $val, self::cacheablePageActions() ) ) {
 				continue;
 			// Below are header setting params
-			} elseif ( $query == 'maxage' || $query == 'smaxage' ) {
+			} elseif ( $query === 'maxage' || $query === 'smaxage' ) {
 				continue;
 			}
 			return false;
diff --git a/includes/cache/ResourceFileCache.php b/includes/cache/ResourceFileCache.php
index 3d725e72a7..36098475e0 100644
--- a/includes/cache/ResourceFileCache.php
+++ b/includes/cache/ResourceFileCache.php
@@ -72,12 +72,15 @@ class ResourceFileCache extends FileCacheBase {
 	}
 
 	/**
-	 * Recent cache misses
+	 * Item has many recent cache misses
 	 * @return bool
 	 */
 	public function isCacheWorthy() {
 		if ( $this->mCacheWorthy === null ) {
-			$this->mCacheWorthy = ( $this->getMissesRecent() >= self::MISS_THRESHOLD );
+			$this->mCacheWorthy = (
+				$this->isCached() || // even stale cache indicates it was cache worthy
+				$this->getMissesRecent() >= self::MISS_THRESHOLD // many misses
+			);
 		}
 		return $this->mCacheWorthy;
 	}
-- 
2.20.1