From 3a70821dab8b4e2d684e34c701ae0184afb14059 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@users.mediawiki.org>
Date: Mon, 14 Sep 2009 21:58:41 +0000
Subject: [PATCH] Clean up a live hack from wmf-deployment r53208: option to
 short-circuit math path and file existence checks. Adds $wgMathCheckFiles
 setting:

/**
 * Normally when generating math images, we double-check that the
 * directories we want to write to exist, and that files that have
 * been generated still exist when we need to bring them up again.
 *
 * This lets us give useful error messages in case of permission
 * problems, and automatically rebuild images that have been lost.
 *
 * On a big site with heavy NFS traffic this can be slow and flaky,
 * so sometimes we want to short-circuit it by setting this to false.
 */
$wgMathCheckFiles = true;
---
 includes/DefaultSettings.php | 13 +++++++++++++
 includes/Math.php            | 22 +++++++++++++++-------
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/includes/DefaultSettings.php b/includes/DefaultSettings.php
index a32795605d..50417ffa45 100644
--- a/includes/DefaultSettings.php
+++ b/includes/DefaultSettings.php
@@ -1864,6 +1864,19 @@ $wgUseTeX = false;
 /** Location of the texvc binary */
 $wgTexvc = './math/texvc';
 
+/**
+ * Normally when generating math images, we double-check that the
+ * directories we want to write to exist, and that files that have
+ * been generated still exist when we need to bring them up again.
+ *
+ * This lets us give useful error messages in case of permission
+ * problems, and automatically rebuild images that have been lost.
+ *
+ * On a big site with heavy NFS traffic this can be slow and flaky,
+ * so sometimes we want to short-circuit it by setting this to false.
+ */
+$wgMathCheckFiles = true;
+
 #
 # Profiling / debugging
 #
diff --git a/includes/Math.php b/includes/Math.php
index 2ed1603376..2e61494486 100644
--- a/includes/Math.php
+++ b/includes/Math.php
@@ -33,7 +33,7 @@ class MathRenderer {
 
 	function render() {
 		global $wgTmpDirectory, $wgInputEncoding;
-		global $wgTexvc;
+		global $wgTexvc, $wgMathCheckFiles;
 		$fname = 'MathRenderer::render';
 
 		if( $this->mode == MW_MATH_SOURCE ) {
@@ -45,13 +45,15 @@ class MathRenderer {
 		}
 
 		if( !$this->_recall() ) {
-			# Ensure that the temp and output directories are available before continuing...
-			if( !file_exists( $wgTmpDirectory ) ) {
-				if( !wfMkdirParents( $wgTmpDirectory ) ) {
+			if( $wgMathCheckFiles ) {
+				# Ensure that the temp and output directories are available before continuing...
+				if( !file_exists( $wgTmpDirectory ) ) {
+					if( !wfMkdirParents( $wgTmpDirectory ) ) {
+						return $this->_error( 'math_bad_tmpdir' );
+					}
+				} elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
 					return $this->_error( 'math_bad_tmpdir' );
 				}
-			} elseif( !is_dir( $wgTmpDirectory ) || !is_writable( $wgTmpDirectory ) ) {
-				return $this->_error( 'math_bad_tmpdir' );
 			}
 
 			if( function_exists( 'is_executable' ) && !is_executable( $wgTexvc ) ) {
@@ -200,7 +202,7 @@ class MathRenderer {
 	}
 
 	function _recall() {
-		global $wgMathDirectory;
+		global $wgMathDirectory, $wgMathCheckFiles;
 		$fname = 'MathRenderer::_recall';
 
 		$this->md5 = md5( $this->tex );
@@ -221,6 +223,12 @@ class MathRenderer {
 			$this->mathml = $rpage->math_mathml;
 
 			$filename = $this->_getHashPath() . "/{$this->hash}.png";
+			
+			if( !$wgMathCheckFiles ) {
+				// Short-circuit the file existence & migration checks
+				return true;
+			}
+			
 			if( file_exists( $filename ) ) {
 				if( filesize( $filename ) == 0 ) {
 					// Some horrible error corrupted stuff :(
-- 
2.20.1