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1 <?php
2 /**
3  * Blocks and bans object
4  */
5
6 /**
7  * The block class
8  * All the functions in this class assume the object is either explicitly
9  * loaded or filled. It is not load-on-demand. There are no accessors.
10  *
11  * Globals used: $wgAutoblockExpiry, $wgAntiLockFlags
12  *
13  * @todo This could be used everywhere, but it isn't.
14  */
15 class Block
16 {
17         /* public*/ var $mAddress, $mUser, $mBy, $mReason, $mTimestamp, $mAuto, $mId, $mExpiry,
18                                 $mRangeStart, $mRangeEnd, $mAnonOnly, $mEnableAutoblock, $mHideName, 
19                                 $mBlockEmail;
20         /* private */ var $mNetworkBits, $mIntegerAddr, $mForUpdate, $mFromMaster, $mByName;
21         
22         const EB_KEEP_EXPIRED = 1;
23         const EB_FOR_UPDATE = 2;
24         const EB_RANGE_ONLY = 4;
25
26         function __construct( $address = '', $user = 0, $by = 0, $reason = '',
27                 $timestamp = '' , $auto = 0, $expiry = '', $anonOnly = 0, $createAccount = 0, $enableAutoblock = 0, 
28                 $hideName = 0, $blockEmail = 0 )
29         {
30                 $this->mId = 0;
31                 # Expand valid IPv6 addresses
32                 $address = IP::sanitizeIP( $address );
33                 $this->mAddress = $address;
34                 $this->mUser = $user;
35                 $this->mBy = $by;
36                 $this->mReason = $reason;
37                 $this->mTimestamp = wfTimestamp(TS_MW,$timestamp);
38                 $this->mAuto = $auto;
39                 $this->mAnonOnly = $anonOnly;
40                 $this->mCreateAccount = $createAccount;
41                 $this->mExpiry = self::decodeExpiry( $expiry );
42                 $this->mEnableAutoblock = $enableAutoblock;
43                 $this->mHideName = $hideName;
44                 $this->mBlockEmail = $blockEmail;
45                 $this->mForUpdate = false;
46                 $this->mFromMaster = false;
47                 $this->mByName = false;
48                 $this->initialiseRange();
49         }
50
51         static function newFromDB( $address, $user = 0, $killExpired = true )
52         {
53                 $block = new Block();
54                 $block->load( $address, $user, $killExpired );
55                 if ( $block->isValid() ) {
56                         return $block;
57                 } else {
58                         return null;
59                 }
60         }
61
62         static function newFromID( $id ) 
63         {
64                 $dbr = wfGetDB( DB_SLAVE );
65                 $res = $dbr->resultObject( $dbr->select( 'ipblocks', '*', 
66                         array( 'ipb_id' => $id ), __METHOD__ ) );
67                 $block = new Block;
68                 if ( $block->loadFromResult( $res ) ) {
69                         return $block;
70                 } else {
71                         return null;
72                 }
73         }
74
75         function clear()
76         {
77                 $this->mAddress = $this->mReason = $this->mTimestamp = '';
78                 $this->mId = $this->mAnonOnly = $this->mCreateAccount = 
79                         $this->mEnableAutoblock = $this->mAuto = $this->mUser = 
80                         $this->mBy = $this->mHideName = $this->mBlockEmail = 0;
81                 $this->mByName = false;
82         }
83
84         /**
85          * Get the DB object and set the reference parameter to the query options
86          */
87         function &getDBOptions( &$options )
88         {
89                 global $wgAntiLockFlags;
90                 if ( $this->mForUpdate || $this->mFromMaster ) {
91                         $db = wfGetDB( DB_MASTER );
92                         if ( !$this->mForUpdate || ($wgAntiLockFlags & ALF_NO_BLOCK_LOCK) ) {
93                                 $options = array();
94                         } else {
95                                 $options = array( 'FOR UPDATE' );
96                         }
97                 } else {
98                         $db = wfGetDB( DB_SLAVE );
99                         $options = array();
100                 }
101                 return $db;
102         }
103
104         /**
105          * Get a ban from the DB, with either the given address or the given username
106          *
107          * @param string $address The IP address of the user, or blank to skip IP blocks
108          * @param integer $user The user ID, or zero for anonymous users
109          * @param bool $killExpired Whether to delete expired rows while loading
110          *
111          */
112         function load( $address = '', $user = 0, $killExpired = true )
113         {
114                 wfDebug( "Block::load: '$address', '$user', $killExpired\n" );
115
116                 $options = array();
117                 $db =& $this->getDBOptions( $options );
118
119                 if ( 0 == $user && $address == '' ) {
120                         # Invalid user specification, not blocked
121                         $this->clear();
122                         return false;
123                 }
124
125                 # Try user block
126                 if ( $user ) {
127                         $res = $db->resultObject( $db->select( 'ipblocks', '*', array( 'ipb_user' => $user ), 
128                                 __METHOD__, $options ) );
129                         if ( $this->loadFromResult( $res, $killExpired ) ) {
130                                 return true;
131                         }
132                 }
133
134                 # Try IP block
135                 # TODO: improve performance by merging this query with the autoblock one
136                 # Slightly tricky while handling killExpired as well
137                 if ( $address ) {
138                         $conds = array( 'ipb_address' => $address, 'ipb_auto' => 0 );
139                         $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );
140                         if ( $this->loadFromResult( $res, $killExpired ) ) {
141                                 if ( $user && $this->mAnonOnly ) {
142                                         # Block is marked anon-only
143                                         # Whitelist this IP address against autoblocks and range blocks
144                                         $this->clear();
145                                         return false;
146                                 } else {
147                                         return true;
148                                 }
149                         }
150                 }
151
152                 # Try range block
153                 if ( $this->loadRange( $address, $killExpired, $user ) ) {
154                         if ( $user && $this->mAnonOnly ) {
155                                 $this->clear();
156                                 return false;
157                         } else {
158                                 return true;
159                         }
160                 }
161
162                 # Try autoblock
163                 if ( $address ) {
164                         $conds = array( 'ipb_address' => $address, 'ipb_auto' => 1 );
165                         if ( $user ) {
166                                 $conds['ipb_anon_only'] = 0;
167                         }
168                         $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );
169                         if ( $this->loadFromResult( $res, $killExpired ) ) {
170                                 return true;
171                         }
172                 }
173                 
174                 # Give up
175                 $this->clear();
176                 return false;
177         }
178
179         /**
180          * Fill in member variables from a result wrapper
181          */
182         function loadFromResult( ResultWrapper $res, $killExpired = true ) 
183         {
184                 $ret = false;
185                 if ( 0 != $res->numRows() ) {
186                         # Get first block
187                         $row = $res->fetchObject();
188                         $this->initFromRow( $row );
189
190                         if ( $killExpired ) {
191                                 # If requested, delete expired rows
192                                 do {
193                                         $killed = $this->deleteIfExpired();
194                                         if ( $killed ) {
195                                                 $row = $res->fetchObject();
196                                                 if ( $row ) {
197                                                         $this->initFromRow( $row );
198                                                 }
199                                         }
200                                 } while ( $killed && $row );
201
202                                 # If there were any left after the killing finished, return true
203                                 if ( $row ) {
204                                         $ret = true;
205                                 }
206                         } else {
207                                 $ret = true;
208                         }
209                 }
210                 $res->free();
211                 return $ret;
212         }
213
214         /**
215          * Search the database for any range blocks matching the given address, and
216          * load the row if one is found.
217          */
218         function loadRange( $address, $killExpired = true, $user = 0 )
219         {
220                 $iaddr = IP::toHex( $address );
221                 if ( $iaddr === false ) {
222                         # Invalid address
223                         return false;
224                 }
225
226                 # Only scan ranges which start in this /16, this improves search speed
227                 # Blocks should not cross a /16 boundary.
228                 $range = substr( $iaddr, 0, 4 );
229
230                 $options = array();
231                 $db =& $this->getDBOptions( $options );
232                 $conds = array(
233                         "ipb_range_start LIKE '$range%'",
234                         "ipb_range_start <= '$iaddr'",
235                         "ipb_range_end >= '$iaddr'"
236                 );
237                 
238                 if ( $user ) {
239                         $conds['ipb_anon_only'] = 0;
240                 }
241
242                 $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );
243                 $success = $this->loadFromResult( $res, $killExpired );
244                 return $success;
245         }
246
247         /**
248          * Determine if a given integer IPv4 address is in a given CIDR network
249          * @deprecated Use IP::isInRange
250          */
251         function isAddressInRange( $addr, $range ) {
252                 return IP::isInRange( $addr, $range );
253         }
254
255         function initFromRow( $row )
256         {
257                 $this->mAddress = $row->ipb_address;
258                 $this->mReason = $row->ipb_reason;
259                 $this->mTimestamp = wfTimestamp(TS_MW,$row->ipb_timestamp);
260                 $this->mUser = $row->ipb_user;
261                 $this->mBy = $row->ipb_by;
262                 $this->mAuto = $row->ipb_auto;
263                 $this->mAnonOnly = $row->ipb_anon_only;
264                 $this->mCreateAccount = $row->ipb_create_account;
265                 $this->mEnableAutoblock = $row->ipb_enable_autoblock;
266                 $this->mBlockEmail = $row->ipb_block_email;
267                 $this->mHideName = $row->ipb_deleted;
268                 $this->mId = $row->ipb_id;
269                 $this->mExpiry = self::decodeExpiry( $row->ipb_expiry );
270                 if ( isset( $row->user_name ) ) {
271                         $this->mByName = $row->user_name;
272                 } else {
273                         $this->mByName = false;
274                 }
275                 $this->mRangeStart = $row->ipb_range_start;
276                 $this->mRangeEnd = $row->ipb_range_end;
277         }
278
279         function initialiseRange()
280         {
281                 $this->mRangeStart = '';
282                 $this->mRangeEnd = '';
283
284                 if ( $this->mUser == 0 ) {
285                         list( $this->mRangeStart, $this->mRangeEnd ) = IP::parseRange( $this->mAddress );
286                 }
287         }
288
289         /**
290          * Callback with a Block object for every block
291          * @return integer number of blocks;
292          */
293         /*static*/ function enumBlocks( $callback, $tag, $flags = 0 )
294         {
295                 global $wgAntiLockFlags;
296
297                 $block = new Block();
298                 if ( $flags & Block::EB_FOR_UPDATE ) {
299                         $db = wfGetDB( DB_MASTER );
300                         if ( $wgAntiLockFlags & ALF_NO_BLOCK_LOCK ) {
301                                 $options = '';
302                         } else {
303                                 $options = 'FOR UPDATE';
304                         }
305                         $block->forUpdate( true );
306                 } else {
307                         $db = wfGetDB( DB_SLAVE );
308                         $options = '';
309                 }
310                 if ( $flags & Block::EB_RANGE_ONLY ) {
311                         $cond = " AND ipb_range_start <> ''";
312                 } else {
313                         $cond = '';
314                 }
315
316                 $now = wfTimestampNow();
317
318                 list( $ipblocks, $user ) = $db->tableNamesN( 'ipblocks', 'user' );
319
320                 $sql = "SELECT $ipblocks.*,user_name FROM $ipblocks,$user " .
321                         "WHERE user_id=ipb_by $cond ORDER BY ipb_timestamp DESC $options";
322                 $res = $db->query( $sql, 'Block::enumBlocks' );
323                 $num_rows = $db->numRows( $res );
324
325                 while ( $row = $db->fetchObject( $res ) ) {
326                         $block->initFromRow( $row );
327                         if ( ( $flags & Block::EB_RANGE_ONLY ) && $block->mRangeStart == '' ) {
328                                 continue;
329                         }
330
331                         if ( !( $flags & Block::EB_KEEP_EXPIRED ) ) {
332                                 if ( $block->mExpiry && $now > $block->mExpiry ) {
333                                         $block->delete();
334                                 } else {
335                                         call_user_func( $callback, $block, $tag );
336                                 }
337                         } else {
338                                 call_user_func( $callback, $block, $tag );
339                         }
340                 }
341                 $db->freeResult( $res );
342                 return $num_rows;
343         }
344
345         function delete()
346         {
347                 if (wfReadOnly()) {
348                         return false;
349                 }
350                 if ( !$this->mId ) {
351                         throw new MWException( "Block::delete() now requires that the mId member be filled\n" );
352                 }
353
354                 $dbw = wfGetDB( DB_MASTER );
355                 $dbw->delete( 'ipblocks', array( 'ipb_id' => $this->mId ), __METHOD__ );
356                 return $dbw->affectedRows() > 0;
357         }
358
359         /**
360         * Insert a block into the block table.
361         *@return Whether or not the insertion was successful.
362         */
363         function insert()
364         {
365                 wfDebug( "Block::insert; timestamp {$this->mTimestamp}\n" );
366                 $dbw = wfGetDB( DB_MASTER );
367
368                 # Unset ipb_anon_only for user blocks, makes no sense
369                 if ( $this->mUser ) {
370                         $this->mAnonOnly = 0;
371                 }
372
373                 # Unset ipb_enable_autoblock for IP blocks, makes no sense
374                 if ( !$this->mUser ) {
375                         $this->mEnableAutoblock = 0;
376                         $this->mBlockEmail = 0; //Same goes for email...
377                 }
378
379                 # Don't collide with expired blocks
380                 Block::purgeExpired();
381
382                 $ipb_id = $dbw->nextSequenceValue('ipblocks_ipb_id_val');
383                 $dbw->insert( 'ipblocks',
384                         array(
385                                 'ipb_id' => $ipb_id,
386                                 'ipb_address' => $this->mAddress,
387                                 'ipb_user' => $this->mUser,
388                                 'ipb_by' => $this->mBy,
389                                 'ipb_reason' => $this->mReason,
390                                 'ipb_timestamp' => $dbw->timestamp($this->mTimestamp),
391                                 'ipb_auto' => $this->mAuto,
392                                 'ipb_anon_only' => $this->mAnonOnly,
393                                 'ipb_create_account' => $this->mCreateAccount,
394                                 'ipb_enable_autoblock' => $this->mEnableAutoblock,
395                                 'ipb_expiry' => self::encodeExpiry( $this->mExpiry, $dbw ),
396                                 'ipb_range_start' => $this->mRangeStart,
397                                 'ipb_range_end' => $this->mRangeEnd,
398                                 'ipb_deleted'   => $this->mHideName,
399                                 'ipb_block_email' => $this->mBlockEmail
400                         ), 'Block::insert', array( 'IGNORE' )
401                 );
402                 $affected = $dbw->affectedRows();
403                 $dbw->commit();
404
405                 if ($affected)
406                         $this->doRetroactiveAutoblock();
407
408                 return $affected;
409         }
410
411         /**
412         * Retroactively autoblocks the last IP used by the user (if it is a user)
413         * blocked by this Block.
414         *@return Whether or not a retroactive autoblock was made.
415         */
416         function doRetroactiveAutoblock() {
417                 $dbr = wfGetDB( DB_SLAVE );
418                 #If autoblock is enabled, autoblock the LAST IP used
419                 # - stolen shamelessly from CheckUser_body.php
420
421                 if ($this->mEnableAutoblock && $this->mUser) {
422                         wfDebug("Doing retroactive autoblocks for " . $this->mAddress . "\n");
423
424                         $row = $dbr->selectRow( 'recentchanges', array( 'rc_ip' ), array( 'rc_user_text' => $this->mAddress ),
425                                 __METHOD__ , array( 'ORDER BY' => 'rc_timestamp DESC' ) );
426
427                         if ( !$row || !$row->rc_ip ) {
428                                 #No results, don't autoblock anything
429                                 wfDebug("No IP found to retroactively autoblock\n");
430                         } else {
431                                 #Limit is 1, so no loop needed.
432                                 $retroblockip = $row->rc_ip;
433                                 return $this->doAutoblock( $retroblockip, true );
434                         }
435                 }
436         }
437
438         /**
439         * Autoblocks the given IP, referring to this Block.
440         * @param string $autoblockip The IP to autoblock.
441         * @param bool $justInserted The main block was just inserted
442         * @return bool Whether or not an autoblock was inserted.
443         */
444         function doAutoblock( $autoblockip, $justInserted = false ) {
445                 # If autoblocks are disabled, go away.
446                 if ( !$this->mEnableAutoblock ) {
447                         return;
448                 }
449
450                 # Check for presence on the autoblock whitelist
451                 # TODO cache this?
452                 $lines = explode( "\n", wfMsgForContentNoTrans( 'autoblock_whitelist' ) );
453
454                 $ip = $autoblockip;
455
456                 wfDebug("Checking the autoblock whitelist..\n");
457
458                 foreach( $lines as $line ) {
459                         # List items only
460                         if ( substr( $line, 0, 1 ) !== '*' ) {
461                                 continue;
462                         }
463
464                         $wlEntry = substr($line, 1);
465                         $wlEntry = trim($wlEntry);
466
467                         wfDebug("Checking $ip against $wlEntry...");
468
469                         # Is the IP in this range?
470                         if (IP::isInRange( $ip, $wlEntry )) {
471                                 wfDebug(" IP $ip matches $wlEntry, not autoblocking\n");
472                                 #$autoblockip = null; # Don't autoblock a whitelisted IP.
473                                 return; #This /SHOULD/ introduce a dummy block - but
474                                         # I don't know a safe way to do so. -werdna
475                         } else {
476                                 wfDebug( " No match\n" );
477                         }
478                 }
479
480                 # It's okay to autoblock. Go ahead and create/insert the block.
481
482                 $ipblock = Block::newFromDB( $autoblockip );
483                 if ( $ipblock ) {
484                         # If the user is already blocked. Then check if the autoblock would
485                         # exceed the user block. If it would exceed, then do nothing, else
486                         # prolong block time
487                         if ($this->mExpiry &&
488                         ($this->mExpiry < Block::getAutoblockExpiry($ipblock->mTimestamp))) {
489                                 return;
490                         }
491                         # Just update the timestamp
492                         if ( !$justInserted ) {
493                                 $ipblock->updateTimestamp();
494                         }
495                         return;
496                 } else {
497                         $ipblock = new Block;
498                 }
499
500                 # Make a new block object with the desired properties
501                 wfDebug( "Autoblocking {$this->mAddress}@" . $autoblockip . "\n" );
502                 $ipblock->mAddress = $autoblockip;
503                 $ipblock->mUser = 0;
504                 $ipblock->mBy = $this->mBy;
505                 $ipblock->mReason = wfMsgForContent( 'autoblocker', $this->mAddress, $this->mReason );
506                 $ipblock->mTimestamp = wfTimestampNow();
507                 $ipblock->mAuto = 1;
508                 $ipblock->mCreateAccount = $this->mCreateAccount;
509                 # Continue suppressing the name if needed
510                 $ipblock->mHideName = $this->mHideName;
511
512                 # If the user is already blocked with an expiry date, we don't
513                 # want to pile on top of that!
514                 if($this->mExpiry) {
515                         $ipblock->mExpiry = min ( $this->mExpiry, Block::getAutoblockExpiry( $this->mTimestamp ));
516                 } else {
517                         $ipblock->mExpiry = Block::getAutoblockExpiry( $this->mTimestamp );
518                 }
519                 # Insert it
520                 return $ipblock->insert();
521         }
522
523         function deleteIfExpired()
524         {
525                 $fname = 'Block::deleteIfExpired';
526                 wfProfileIn( $fname );
527                 if ( $this->isExpired() ) {
528                         wfDebug( "Block::deleteIfExpired() -- deleting\n" );
529                         $this->delete();
530                         $retVal = true;
531                 } else {
532                         wfDebug( "Block::deleteIfExpired() -- not expired\n" );
533                         $retVal = false;
534                 }
535                 wfProfileOut( $fname );
536                 return $retVal;
537         }
538
539         function isExpired()
540         {
541                 wfDebug( "Block::isExpired() checking current " . wfTimestampNow() . " vs $this->mExpiry\n" );
542                 if ( !$this->mExpiry ) {
543                         return false;
544                 } else {
545                         return wfTimestampNow() > $this->mExpiry;
546                 }
547         }
548
549         function isValid()
550         {
551                 return $this->mAddress != '';
552         }
553
554         function updateTimestamp()
555         {
556                 if ( $this->mAuto ) {
557                         $this->mTimestamp = wfTimestamp();
558                         $this->mExpiry = Block::getAutoblockExpiry( $this->mTimestamp );
559
560                         $dbw = wfGetDB( DB_MASTER );
561                         $dbw->update( 'ipblocks',
562                                 array( /* SET */
563                                         'ipb_timestamp' => $dbw->timestamp($this->mTimestamp),
564                                         'ipb_expiry' => $dbw->timestamp($this->mExpiry),
565                                 ), array( /* WHERE */
566                                         'ipb_address' => $this->mAddress
567                                 ), 'Block::updateTimestamp'
568                         );
569                 }
570         }
571
572         /*
573         function getIntegerAddr()
574         {
575                 return $this->mIntegerAddr;
576         }
577
578         function getNetworkBits()
579         {
580                 return $this->mNetworkBits;
581         }*/
582
583         /**
584          * @return The blocker user ID.
585          */
586         public function getBy() {
587                 return $this->mBy;
588         }
589
590         /**
591          * @return The blocker user name.
592          */
593         function getByName()
594         {
595                 if ( $this->mByName === false ) {
596                         $this->mByName = User::whoIs( $this->mBy );
597                 }
598                 return $this->mByName;
599         }
600
601         function forUpdate( $x = NULL ) {
602                 return wfSetVar( $this->mForUpdate, $x );
603         }
604
605         function fromMaster( $x = NULL ) {
606                 return wfSetVar( $this->mFromMaster, $x );
607         }
608
609         function getRedactedName() {
610                 if ( $this->mAuto ) {
611                         return '#' . $this->mId;
612                 } else {
613                         return $this->mAddress;
614                 }
615         }
616         
617         /**
618          * Encode expiry for DB
619          */
620         static function encodeExpiry( $expiry, $db ) {
621                 if ( $expiry == '' || $expiry == Block::infinity() ) {
622                         return Block::infinity();
623                 } else {
624                         return $db->timestamp( $expiry );
625                 }
626         }
627
628         /** 
629          * Decode expiry which has come from the DB
630          */
631         static function decodeExpiry( $expiry, $timestampType = TS_MW ) {
632                 if ( $expiry == '' || $expiry == Block::infinity() ) {
633                         return Block::infinity();
634                 } else {
635                         return wfTimestamp( $timestampType, $expiry );
636                 }
637         }
638         
639         static function getAutoblockExpiry( $timestamp )
640         {
641                 global $wgAutoblockExpiry;
642                 return wfTimestamp( TS_MW, wfTimestamp( TS_UNIX, $timestamp ) + $wgAutoblockExpiry );
643         }
644         
645         /** 
646          * Gets rid of uneeded numbers in quad-dotted/octet IP strings
647          * For example, 127.111.113.151/24 -> 127.111.113.0/24
648          */
649         static function normaliseRange( $range ) {
650                 $parts = explode( '/', $range );
651                 if ( count( $parts ) == 2 ) {
652                         // IPv6
653                         if ( IP::isIPv6($range) && $parts[1] >= 64 && $parts[1] <= 128 ) {
654                                 $bits = $parts[1];
655                                 $ipint = IP::toUnsigned6( $parts[0] );
656                                 # Native 32 bit functions WONT work here!!!
657                                 # Convert to a padded binary number
658                                 $network = wfBaseConvert( $ipint, 10, 2, 128 );
659                                 # Truncate the last (128-$bits) bits and replace them with zeros
660                                 $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
661                                 # Convert back to an integer
662                                 $network = wfBaseConvert( $network, 2, 10 );
663                                 # Reform octet address
664                                 $newip = IP::toOctet( $network );
665                                 $range = "$newip/{$parts[1]}";
666                         } // IPv4
667                         else if ( IP::isIPv4($range) && $parts[1] >= 16 && $parts[1] <= 32 ) {
668                                 $shift = 32 - $parts[1];
669                                 $ipint = IP::toUnsigned( $parts[0] );
670                                 $ipint = $ipint >> $shift << $shift;
671                                 $newip = long2ip( $ipint );
672                                 $range = "$newip/{$parts[1]}";
673                         }
674                 }
675                 return $range;
676         }
677
678         /** 
679          * Purge expired blocks from the ipblocks table
680          */
681         static function purgeExpired() {
682                 $dbw = wfGetDB( DB_MASTER );
683                 $dbw->delete( 'ipblocks', array( 'ipb_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ), __METHOD__ );
684         }
685
686         static function infinity() {
687                 # This is a special keyword for timestamps in PostgreSQL, and 
688                 # works with CHAR(14) as well because "i" sorts after all numbers.              
689                 return 'infinity';
690
691                 /*
692                 static $infinity;
693                 if ( !isset( $infinity ) ) {
694                         $dbr = wfGetDB( DB_SLAVE );
695                         $infinity = $dbr->bigTimestamp();
696                 }
697                 return $infinity;
698                  */
699         }
700
701 }
702