<?php
+/**
+ * Efficient concatenated text storage.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
/**
- * Base class for general text storage via the "object" flag in old_flags, or
- * two-part external storage URLs. Used for represent efficient concatenated
+ * Base class for general text storage via the "object" flag in old_flags, or
+ * two-part external storage URLs. Used for represent efficient concatenated
* storage, and migration-related pointer objects.
*/
interface HistoryBlob
* @return bool
*/
public function isHappy() {
- return $this->mSize < $this->mMaxSize
+ return $this->mSize < $this->mMaxSize
&& count( $this->mItems ) < $this->mMaxCount;
}
}
var $mOldId, $mHash, $mRef;
/**
- * @param $hash Strng: the content hash of the text
- * @param $oldid Integer: the old_id for the CGZ object
+ * @param $hash string the content hash of the text
+ * @param $oldid Integer the old_id for the CGZ object
*/
function __construct( $hash = '', $oldid = 0 ) {
$this->mHash = $hash;
$flags = explode( ',', $row->old_flags );
if( in_array( 'external', $flags ) ) {
$url=$row->old_text;
- @list( /* $proto */ ,$path)=explode('://',$url,2);
- if ( $path == "" ) {
+ $parts = explode( '://', $url, 2 );
+ if ( !isset( $parts[1] ) || $parts[1] == '' ) {
wfProfileOut( $fname );
return false;
}
}
/**
- * @return string|false
+ * @return string|bool
*/
function getText() {
$dbr = wfGetDB( DB_SLAVE );
/** Total uncompressed size */
var $mSize = 0;
- /**
- * Array of diffs. If a diff D from A to B is notated D = B - A, and Z is
+ /**
+ * Array of diffs. If a diff D from A to B is notated D = B - A, and Z is
* an empty string:
*
* { item[map[i]] - item[map[i-1]] where i > 0
- * diff[i] = {
+ * diff[i] = {
* { item[map[i]] - Z where i = 0
*/
var $mDiffs;
* The maximum number of text items before the object becomes sad
*/
var $mMaxCount = 100;
-
+
/** Constants from xdiff.h */
const XDL_BDOP_INS = 1;
const XDL_BDOP_CPY = 2;
* @throws MWException
*/
function compress() {
- if ( !function_exists( 'xdiff_string_rabdiff' ) ){
+ if ( !function_exists( 'xdiff_string_rabdiff' ) ){
throw new MWException( "Need xdiff 1.5+ support to write DiffHistoryBlob\n" );
}
if ( isset( $this->mDiffs ) ) {
# Pure PHP implementation
$header = unpack( 'Vofp/Vcsize', substr( $diff, 0, 8 ) );
-
- # Check the checksum if mhash is available
- if ( extension_loaded( 'mhash' ) ) {
- $ofp = mhash( MHASH_ADLER32, $base );
- if ( $ofp !== substr( $diff, 0, 4 ) ) {
- wfDebug( __METHOD__. ": incorrect base checksum\n" );
- return false;
- }
+
+ # Check the checksum if hash/mhash is available
+ $ofp = $this->xdiffAdler32( $base );
+ if ( $ofp !== false && $ofp !== substr( $diff, 0, 4 ) ) {
+ wfDebug( __METHOD__. ": incorrect base checksum\n" );
+ return false;
}
if ( $header['csize'] != strlen( $base ) ) {
wfDebug( __METHOD__. ": incorrect base length\n" );
return false;
}
-
+
$p = 8;
$out = '';
while ( $p < strlen( $diff ) ) {
return $out;
}
+ /**
+ * Compute a binary "Adler-32" checksum as defined by LibXDiff, i.e. with
+ * the bytes backwards and initialised with 0 instead of 1. See bug 34428.
+ *
+ * Returns false if no hashing library is available
+ */
+ function xdiffAdler32( $s ) {
+ static $init;
+ if ( $init === null ) {
+ $init = str_repeat( "\xf0", 205 ) . "\xee" . str_repeat( "\xf0", 67 ) . "\x02";
+ }
+ // The real Adler-32 checksum of $init is zero, so it initialises the
+ // state to zero, as it is at the start of LibXDiff's checksum
+ // algorithm. Appending the subject string then simulates LibXDiff.
+ if ( function_exists( 'hash' ) ) {
+ $hash = hash( 'adler32', $init . $s, true );
+ } elseif ( function_exists( 'mhash' ) ) {
+ $hash = mhash( MHASH_ADLER32, $init . $s );
+ } else {
+ return false;
+ }
+ return strrev( $hash );
+ }
+
function uncompress() {
if ( !$this->mDiffs ) {
return;
if ( isset( $info['base'] ) ) {
// Old format
$this->mDiffMap = range( 0, count( $this->mDiffs ) - 1 );
- array_unshift( $this->mDiffs,
+ array_unshift( $this->mDiffs,
pack( 'VVCV', 0, 0, self::XDL_BDOP_INSB, strlen( $info['base'] ) ) .
$info['base'] );
} else {
* @return bool
*/
function isHappy() {
- return $this->mSize < $this->mMaxSize
+ return $this->mSize < $this->mMaxSize
&& count( $this->mItems ) < $this->mMaxCount;
}