Merge fixes to ?preload= from /branches/conrad/ (cf. bug 5210, r62864, r62035)

[lhc/web/wiklou.git] / includes / HistoryBlob.php

diff --git a/includes/HistoryBlob.php b/includes/HistoryBlob.php
index 7489399..8336059 100644 (file)
--- a/includes/HistoryBlob.php
+++ b/includes/HistoryBlob.php
@@ -11,12 +11,15 @@ interface HistoryBlob
         * Adds an item of text, returns a stub object which points to the item.
         * You must call setLocation() on the stub object before storing it to the
         * database
-        * Returns the key for getItem()
+        *
+        * @return String: the key for getItem()
         */
        public function addItem( $text );
 
        /**
         * Get item by key, or false if the key is not present
+        *
+        * @return String or false
         */
        public function getItem( $key );
 
@@ -32,6 +35,8 @@ interface HistoryBlob
 
        /**
         * Get default text. This is called from Revision::getRevisionText()
+        *
+        * @return String
         */
        function getText();
 }
@@ -149,8 +154,8 @@ class HistoryBlobStub {
        var $mOldId, $mHash, $mRef;
 
        /**
-        * @param string $hash The content hash of the text
-        * @param integer $oldid The old_id for the CGZ object
+        * @param $hash Strng: the content hash of the text
+        * @param $oldid Integer: the old_id for the CGZ object
         */
        function HistoryBlobStub( $hash = '', $oldid = 0 ) {
                $this->mHash = $hash;
@@ -246,7 +251,7 @@ class HistoryBlobCurStub {
        var $mCurId;
 
        /**
-        * @param integer $curid The cur_id pointed to
+        * @param $curid Integer: the cur_id pointed to
         */
        function HistoryBlobCurStub( $curid = 0 ) {
                $this->mCurId = $curid;
@@ -319,11 +324,13 @@ class DiffHistoryBlob implements HistoryBlob {
         * 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;
+       const XDL_BDOP_INSB = 3;
 
        function __construct() {
-               if ( !function_exists( 'xdiff_string_bdiff' ) ){ 
-                       throw new MWException( "Need xdiff 1.5+ support to read or write DiffHistoryBlob\n" );
-               }
                if ( !function_exists( 'gzdeflate' ) ) {
                        throw new MWException( "Need zlib support to read or write DiffHistoryBlob\n" );
                }
@@ -353,6 +360,9 @@ class DiffHistoryBlob implements HistoryBlob {
        }
 
        function compress() {
+               if ( !function_exists( 'xdiff_string_rabdiff' ) ){ 
+                       throw new MWException( "Need xdiff 1.5+ support to write DiffHistoryBlob\n" );
+               }
                if ( isset( $this->mDiffs ) ) {
                        // Already compressed
                        return;
@@ -425,16 +435,66 @@ class DiffHistoryBlob implements HistoryBlob {
                # Need to do a null concatenation with warnings off, due to bugs in the current version of xdiff
                # "String is not zero-terminated"
                wfSuppressWarnings();
-               $diff = xdiff_string_bdiff( $t1, $t2 ) . '';
+               $diff = xdiff_string_rabdiff( $t1, $t2 ) . '';
                wfRestoreWarnings();
                return $diff;
        }
 
        function patch( $base, $diff ) {
-               wfSuppressWarnings();
-               $text = xdiff_string_bpatch( $base, $diff ) . '';
-               wfRestoreWarnings();
-               return $text;
+               if ( function_exists( 'xdiff_string_bpatch' ) ) {
+                       wfSuppressWarnings();
+                       $text = xdiff_string_bpatch( $base, $diff ) . '';
+                       wfRestoreWarnings();
+                       return $text;
+               }
+
+               # 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;
+                       }
+               }
+               if ( $header['csize'] != strlen( $base ) ) {
+                       wfDebug( __METHOD__. ": incorrect base length\n" );
+                       return false;
+               }
+               
+               $p = 8;
+               $out = '';
+               while ( $p < strlen( $diff ) ) {
+                       $x = unpack( 'Cop', substr( $diff, $p, 1 ) );
+                       $op = $x['op'];
+                       ++$p;
+                       switch ( $op ) {
+                       case self::XDL_BDOP_INS:
+                               $x = unpack( 'Csize', substr( $diff, $p, 1 ) );
+                               $p++;
+                               $out .= substr( $diff, $p, $x['size'] );
+                               $p += $x['size'];
+                               break;
+                       case self::XDL_BDOP_INSB:
+                               $x = unpack( 'Vcsize', substr( $diff, $p, 4 ) );
+                               $p += 4;
+                               $out .= substr( $diff, $p, $x['csize'] );
+                               $p += $x['csize'];
+                               break;
+                       case self::XDL_BDOP_CPY:
+                               $x = unpack( 'Voff/Vcsize', substr( $diff, $p, 8 ) );
+                               $p += 8;
+                               $out .= substr( $base, $x['off'], $x['csize'] );
+                               break;
+                       default:
+                               wfDebug( __METHOD__.": invalid op\n" );
+                               return false;
+                       }
+               }
+               return $out;
        }
 
        function uncompress() {
@@ -492,14 +552,23 @@ class DiffHistoryBlob implements HistoryBlob {
                if ( isset( $info['default'] ) ) {
                        $this->mDefaultKey = $info['default'];
                }
-               $map = explode( ',', $info['map'] );
-               $cur = 0;
-               $this->mDiffMap = array();
-               foreach ( $map as $i ) {
-                       $cur += $i;
-                       $this->mDiffMap[] = $cur;
-               }
                $this->mDiffs = $info['diffs'];
+               if ( isset( $info['base'] ) ) {
+                       // Old format
+                       $this->mDiffMap = range( 0, count( $this->mDiffs ) - 1 );
+                       array_unshift( $this->mDiffs, 
+                               pack( 'VVCV', 0, 0, self::XDL_BDOP_INSB, strlen( $info['base'] ) ) .
+                               $info['base'] );
+               } else {
+                       // New format
+                       $map = explode( ',', $info['map'] );
+                       $cur = 0;
+                       $this->mDiffMap = array();
+                       foreach ( $map as $i ) {
+                               $cur += $i;
+                               $this->mDiffMap[] = $cur;
+                       }
+               }
                $this->uncompress();
        }