Restored line accidentally removed in r70520

[mediawiki.git] / includes / Block.php

<?php
/**
 * @file
 * Blocks and bans object
 */

/**
 * The block class
 * All the functions in this class assume the object is either explicitly
 * loaded or filled. It is not load-on-demand. There are no accessors.
 *
 * Globals used: $wgAutoblockExpiry, $wgAntiLockFlags
 *
 * @todo This could be used everywhere, but it isn't.
 */
class Block {
        /* public*/ var $mAddress, $mUser, $mBy, $mReason, $mTimestamp, $mAuto, $mId, $mExpiry,
                                $mRangeStart, $mRangeEnd, $mAnonOnly, $mEnableAutoblock, $mHideName,
                                $mBlockEmail, $mByName, $mAngryAutoblock, $mAllowUsertalk;
        /* private */ var $mNetworkBits, $mIntegerAddr, $mForUpdate, $mFromMaster;

        const EB_KEEP_EXPIRED = 1;
        const EB_FOR_UPDATE = 2;
        const EB_RANGE_ONLY = 4;

        function __construct( $address = '', $user = 0, $by = 0, $reason = '',
                $timestamp = '' , $auto = 0, $expiry = '', $anonOnly = 0, $createAccount = 0, $enableAutoblock = 0,
                $hideName = 0, $blockEmail = 0, $allowUsertalk = 0, $byName = false )
        {
                $this->mId = 0;
                # Expand valid IPv6 addresses
                $address = IP::sanitizeIP( $address );
                $this->mAddress = $address;
                $this->mUser = $user;
                $this->mBy = $by;
                $this->mReason = $reason;
                $this->mTimestamp = wfTimestamp( TS_MW, $timestamp );
                $this->mAuto = $auto;
                $this->mAnonOnly = $anonOnly;
                $this->mCreateAccount = $createAccount;
                $this->mExpiry = self::decodeExpiry( $expiry );
                $this->mEnableAutoblock = $enableAutoblock;
                $this->mHideName = $hideName;
                $this->mBlockEmail = $blockEmail;
                $this->mAllowUsertalk = $allowUsertalk;
                $this->mForUpdate = false;
                $this->mFromMaster = false;
                $this->mByName = $byName;
                $this->mAngryAutoblock = false;
                $this->initialiseRange();
        }

        /**
         * Load a block from the database, using either the IP address or
         * user ID. Tries the user ID first, and if that doesn't work, tries
         * the address.
         *
         * @param $address String: IP address of user/anon
         * @param $user Integer: user id of user
         * @param $killExpired Boolean: delete expired blocks on load
         * @return Block Object
         */
        public static function newFromDB( $address, $user = 0, $killExpired = true ) {
                $block = new Block;
                $block->load( $address, $user, $killExpired );

                if ( $block->isValid() ) {
                        return $block;
                } else {
                        return null;
                }
        }

        /**
         * Load a blocked user from their block id.
         *
         * @param $id Integer: Block id to search for
         * @return Block object
         */
        public static function newFromID( $id ) {
                $dbr = wfGetDB( DB_SLAVE );
                $res = $dbr->resultObject( $dbr->select( 'ipblocks', '*',
                        array( 'ipb_id' => $id ), __METHOD__ ) );
                $block = new Block;

                if ( $block->loadFromResult( $res ) ) {
                        return $block;
                } else {
                        return null;
                }
        }

        /**
         * Check if two blocks are effectively equal
         *
         * @return Boolean
         */
        public function equals( Block $block ) {
                return (
                        $this->mAddress == $block->mAddress
                        && $this->mUser == $block->mUser
                        && $this->mAuto == $block->mAuto
                        && $this->mAnonOnly == $block->mAnonOnly
                        && $this->mCreateAccount == $block->mCreateAccount
                        && $this->mExpiry == $block->mExpiry
                        && $this->mEnableAutoblock == $block->mEnableAutoblock
                        && $this->mHideName == $block->mHideName
                        && $this->mBlockEmail == $block->mBlockEmail
                        && $this->mAllowUsertalk == $block->mAllowUsertalk
                        && $this->mReason == $block->mReason
                );
        }

        /**
         * Clear all member variables in the current object. Does not clear
         * the block from the DB.
         */
        public function clear() {
                $this->mAddress = $this->mReason = $this->mTimestamp = '';
                $this->mId = $this->mAnonOnly = $this->mCreateAccount =
                        $this->mEnableAutoblock = $this->mAuto = $this->mUser =
                        $this->mBy = $this->mHideName = $this->mBlockEmail = $this->mAllowUsertalk = 0;
                $this->mByName = false;
        }

        /**
         * Get the DB object and set the reference parameter to the select options.
         * The options array will contain FOR UPDATE if appropriate.
         *
         * @param $options Array
         * @return Database
         */
        protected function &getDBOptions( &$options ) {
                global $wgAntiLockFlags;

                if ( $this->mForUpdate || $this->mFromMaster ) {
                        $db = wfGetDB( DB_MASTER );
                        if ( !$this->mForUpdate || ( $wgAntiLockFlags & ALF_NO_BLOCK_LOCK ) ) {
                                $options = array();
                        } else {
                                $options = array( 'FOR UPDATE' );
                        }
                } else {
                        $db = wfGetDB( DB_SLAVE );
                        $options = array();
                }

                return $db;
        }

        /**
         * Get a block from the DB, with either the given address or the given username
         *
         * @param $address string The IP address of the user, or blank to skip IP blocks
         * @param $user int The user ID, or zero for anonymous users
         * @param $killExpired bool Whether to delete expired rows while loading
         * @return Boolean: the user is blocked from editing
         *
         */
        public function load( $address = '', $user = 0, $killExpired = true ) {
                wfDebug( "Block::load: '$address', '$user', $killExpired\n" );

                $options = array();
                $db = $this->getDBOptions( $options );

                if ( 0 == $user && $address === '' ) {
                        # Invalid user specification, not blocked
                        $this->clear();

                        return false;
                }

                # Try user block
                if ( $user ) {
                        $res = $db->resultObject( $db->select( 'ipblocks', '*', array( 'ipb_user' => $user ),
                                __METHOD__, $options ) );

                        if ( $this->loadFromResult( $res, $killExpired ) ) {
                                return true;
                        }
                }

                # Try IP block
                # TODO: improve performance by merging this query with the autoblock one
                # Slightly tricky while handling killExpired as well
                if ( $address !== '' ) {
                        $conds = array( 'ipb_address' => $address, 'ipb_auto' => 0 );
                        $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );

                        if ( $this->loadFromResult( $res, $killExpired ) ) {
                                if ( $user && $this->mAnonOnly ) {
                                        # Block is marked anon-only
                                        # Whitelist this IP address against autoblocks and range blocks
                                        # (but not account creation blocks -- bug 13611)
                                        if ( !$this->mCreateAccount ) {
                                                $this->clear();
                                        }

                                        return false;
                                } else {
                                        return true;
                                }
                        }
                }

                # Try range block
                if ( $this->loadRange( $address, $killExpired, $user ) ) {
                        if ( $user && $this->mAnonOnly ) {
                                # Respect account creation blocks on logged-in users -- bug 13611
                                if ( !$this->mCreateAccount ) {
                                        $this->clear();
                                }

                                return false;
                        } else {
                                return true;
                        }
                }

                # Try autoblock
                if ( $address ) {
                        $conds = array( 'ipb_address' => $address, 'ipb_auto' => 1 );

                        if ( $user ) {
                                $conds['ipb_anon_only'] = 0;
                        }

                        $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );

                        if ( $this->loadFromResult( $res, $killExpired ) ) {
                                return true;
                        }
                }

                # Give up
                $this->clear();
                return false;
        }

        /**
         * Fill in member variables from a result wrapper
         *
         * @param $res ResultWrapper: row from the ipblocks table
         * @param $killExpired Boolean: whether to delete expired rows while loading
         * @return Boolean
         */
        protected function loadFromResult( ResultWrapper $res, $killExpired = true ) {
                $ret = false;

                if ( 0 != $res->numRows() ) {
                        # Get first block
                        $row = $res->fetchObject();
                        $this->initFromRow( $row );

                        if ( $killExpired ) {
                                # If requested, delete expired rows
                                do {
                                        $killed = $this->deleteIfExpired();
                                        if ( $killed ) {
                                                $row = $res->fetchObject();
                                                if ( $row ) {
                                                        $this->initFromRow( $row );
                                                }
                                        }
                                } while ( $killed && $row );

                                # If there were any left after the killing finished, return true
                                if ( $row ) {
                                        $ret = true;
                                }
                        } else {
                                $ret = true;
                        }
                }
                $res->free();

                return $ret;
        }

        /**
         * Search the database for any range blocks matching the given address, and
         * load the row if one is found.
         *
         * @param $address String: IP address range
         * @param $killExpired Boolean: whether to delete expired rows while loading
         * @param $user Integer: if not 0, then sets ipb_anon_only
         * @return Boolean
         */
        public function loadRange( $address, $killExpired = true, $user = 0 ) {
                $iaddr = IP::toHex( $address );

                if ( $iaddr === false ) {
                        # Invalid address
                        return false;
                }

                # Only scan ranges which start in this /16, this improves search speed
                # Blocks should not cross a /16 boundary.
                $range = substr( $iaddr, 0, 4 );

                $options = array();
                $db = $this->getDBOptions( $options );
                $conds = array(
                        'ipb_range_start' . $db->buildLike( $range, $db->anyString() ),
                        "ipb_range_start <= '$iaddr'",
                        "ipb_range_end >= '$iaddr'"
                );

                if ( $user ) {
                        $conds['ipb_anon_only'] = 0;
                }

                $res = $db->resultObject( $db->select( 'ipblocks', '*', $conds, __METHOD__, $options ) );
                $success = $this->loadFromResult( $res, $killExpired );

                return $success;
        }

        /**
         * Given a database row from the ipblocks table, initialize
         * member variables
         *
         * @param $row ResultWrapper: a row from the ipblocks table
         */
        public function initFromRow( $row ) {
                $this->mAddress = $row->ipb_address;
                $this->mReason = $row->ipb_reason;
                $this->mTimestamp = wfTimestamp( TS_MW, $row->ipb_timestamp );
                $this->mUser = $row->ipb_user;
                $this->mBy = $row->ipb_by;
                $this->mAuto = $row->ipb_auto;
                $this->mAnonOnly = $row->ipb_anon_only;
                $this->mCreateAccount = $row->ipb_create_account;
                $this->mEnableAutoblock = $row->ipb_enable_autoblock;
                $this->mBlockEmail = $row->ipb_block_email;
                $this->mAllowUsertalk = $row->ipb_allow_usertalk;
                $this->mHideName = $row->ipb_deleted;
                $this->mId = $row->ipb_id;
                $this->mExpiry = self::decodeExpiry( $row->ipb_expiry );

                if ( isset( $row->user_name ) ) {
                        $this->mByName = $row->user_name;
                } else {
                        $this->mByName = $row->ipb_by_text;
                }

                $this->mRangeStart = $row->ipb_range_start;
                $this->mRangeEnd = $row->ipb_range_end;
        }

        /**
         * Once $mAddress has been set, get the range they came from.
         * Wrapper for IP::parseRange
         */
        protected function initialiseRange() {
                $this->mRangeStart = '';
                $this->mRangeEnd = '';

                if ( $this->mUser == 0 ) {
                        list( $this->mRangeStart, $this->mRangeEnd ) = IP::parseRange( $this->mAddress );
                }
        }

        /**
         * Delete the row from the IP blocks table.
         *
         * @return Boolean
         */
        public function delete() {
                if ( wfReadOnly() ) {
                        return false;
                }

                if ( !$this->mId ) {
                        throw new MWException( "Block::delete() now requires that the mId member be filled\n" );
                }

                $dbw = wfGetDB( DB_MASTER );
                $dbw->delete( 'ipblocks', array( 'ipb_id' => $this->mId ), __METHOD__ );

                return $dbw->affectedRows() > 0;
        }

        /**
         * Insert a block into the block table. Will fail if there is a conflicting
         * block (same name and options) already in the database.
         *
         * @return Boolean: whether or not the insertion was successful.
         */
        public function insert( $dbw = null ) {
                wfDebug( "Block::insert; timestamp {$this->mTimestamp}\n" );

                if ( $dbw === null )
                        $dbw = wfGetDB( DB_MASTER );

                $this->validateBlockParams();
                $this->initialiseRange();

                # Don't collide with expired blocks
                Block::purgeExpired();

                $ipb_id = $dbw->nextSequenceValue( 'ipblocks_ipb_id_seq' );
                $dbw->insert(
                        'ipblocks',
                        array(
                                'ipb_id' => $ipb_id,
                                'ipb_address' => $this->mAddress,
                                'ipb_user' => $this->mUser,
                                'ipb_by' => $this->mBy,
                                'ipb_by_text' => $this->mByName,
                                'ipb_reason' => $this->mReason,
                                'ipb_timestamp' => $dbw->timestamp( $this->mTimestamp ),
                                'ipb_auto' => $this->mAuto,
                                'ipb_anon_only' => $this->mAnonOnly,
                                'ipb_create_account' => $this->mCreateAccount,
                                'ipb_enable_autoblock' => $this->mEnableAutoblock,
                                'ipb_expiry' => self::encodeExpiry( $this->mExpiry, $dbw ),
                                'ipb_range_start' => $this->mRangeStart,
                                'ipb_range_end' => $this->mRangeEnd,
                                'ipb_deleted'   => intval( $this->mHideName ), // typecast required for SQLite
                                'ipb_block_email' => $this->mBlockEmail,
                                'ipb_allow_usertalk' => $this->mAllowUsertalk
                        ),
                        'Block::insert',
                        array( 'IGNORE' )
                );
                $affected = $dbw->affectedRows();

                if ( $affected )
                        $this->doRetroactiveAutoblock();

                return (bool)$affected;
        }

        /**
         * Update a block in the DB with new parameters.
         * The ID field needs to be loaded first.
         */
        public function update() {
                wfDebug( "Block::update; timestamp {$this->mTimestamp}\n" );
                $dbw = wfGetDB( DB_MASTER );

                $this->validateBlockParams();

                $dbw->update(
                        'ipblocks',
                        array(
                                'ipb_user' => $this->mUser,
                                'ipb_by' => $this->mBy,
                                'ipb_by_text' => $this->mByName,
                                'ipb_reason' => $this->mReason,
                                'ipb_timestamp' => $dbw->timestamp( $this->mTimestamp ),
                                'ipb_auto' => $this->mAuto,
                                'ipb_anon_only' => $this->mAnonOnly,
                                'ipb_create_account' => $this->mCreateAccount,
                                'ipb_enable_autoblock' => $this->mEnableAutoblock,
                                'ipb_expiry' => self::encodeExpiry( $this->mExpiry, $dbw ),
                                'ipb_range_start' => $this->mRangeStart,
                                'ipb_range_end' => $this->mRangeEnd,
                                'ipb_deleted'   => $this->mHideName,
                                'ipb_block_email' => $this->mBlockEmail,
                                'ipb_allow_usertalk' => $this->mAllowUsertalk
                        ),
                        array( 'ipb_id' => $this->mId ),
                        'Block::update'
                );

                return $dbw->affectedRows();
        }

        /**
         * Make sure all the proper members are set to sane values
         * before adding/updating a block
         */
        protected function validateBlockParams() {
                # Unset ipb_anon_only for user blocks, makes no sense
                if ( $this->mUser ) {
                        $this->mAnonOnly = 0;
                }

                # Unset ipb_enable_autoblock for IP blocks, makes no sense
                if ( !$this->mUser ) {
                        $this->mEnableAutoblock = 0;
                }

                # bug 18860: non-anon-only IP blocks should be allowed to block email
                if ( !$this->mUser && $this->mAnonOnly ) {
                        $this->mBlockEmail = 0;
                }

                if ( !$this->mByName ) {
                        if ( $this->mBy ) {
                                $this->mByName = User::whoIs( $this->mBy );
                        } else {
                                global $wgUser;
                                $this->mByName = $wgUser->getName();
                        }
                }
        }

        /**
         * Retroactively autoblocks the last IP used by the user (if it is a user)
         * blocked by this Block.
         *
         * @return Boolean: whether or not a retroactive autoblock was made.
         */
        public function doRetroactiveAutoblock() {
                $dbr = wfGetDB( DB_SLAVE );
                # If autoblock is enabled, autoblock the LAST IP used
                # - stolen shamelessly from CheckUser_body.php

                if ( $this->mEnableAutoblock && $this->mUser ) {
                        wfDebug( "Doing retroactive autoblocks for " . $this->mAddress . "\n" );

                        $options = array( 'ORDER BY' => 'rc_timestamp DESC' );
                        $conds = array( 'rc_user_text' => $this->mAddress );

                        if ( $this->mAngryAutoblock ) {
                                // Block any IP used in the last 7 days. Up to five IPs.
                                $conds[] = 'rc_timestamp < ' . $dbr->addQuotes( $dbr->timestamp( time() - ( 7 * 86400 ) ) );
                                $options['LIMIT'] = 5;
                        } else {
                                // Just the last IP used.
                                $options['LIMIT'] = 1;
                        }

                        $res = $dbr->select( 'recentchanges', array( 'rc_ip' ), $conds,
                                __METHOD__ ,  $options );

                        if ( !$dbr->numRows( $res ) ) {
                                # No results, don't autoblock anything
                                wfDebug( "No IP found to retroactively autoblock\n" );
                        } else {
                                while ( $row = $dbr->fetchObject( $res ) ) {
                                        if ( $row->rc_ip ) {
                                                $this->doAutoblock( $row->rc_ip );
                                        }
                                }
                        }
                }
        }

        /**
         * Checks whether a given IP is on the autoblock whitelist.
         *
         * @param $ip String: The IP to check
         * @return Boolean
         */
        public static function isWhitelistedFromAutoblocks( $ip ) {
                global $wgMemc;

                // Try to get the autoblock_whitelist from the cache, as it's faster
                // than getting the msg raw and explode()'ing it.
                $key = wfMemcKey( 'ipb', 'autoblock', 'whitelist' );
                $lines = $wgMemc->get( $key );
                if ( !$lines ) {
                        $lines = explode( "\n", wfMsgForContentNoTrans( 'autoblock_whitelist' ) );
                        $wgMemc->set( $key, $lines, 3600 * 24 );
                }

                wfDebug( "Checking the autoblock whitelist..\n" );

                foreach ( $lines as $line ) {
                        # List items only
                        if ( substr( $line, 0, 1 ) !== '*' ) {
                                continue;
                        }

                        $wlEntry = substr( $line, 1 );
                        $wlEntry = trim( $wlEntry );

                        wfDebug( "Checking $ip against $wlEntry..." );

                        # Is the IP in this range?
                        if ( IP::isInRange( $ip, $wlEntry ) ) {
                                wfDebug( " IP $ip matches $wlEntry, not autoblocking\n" );
                                return true;
                        } else {
                                wfDebug( " No match\n" );
                        }
                }

                return false;
        }

        /**
         * Autoblocks the given IP, referring to this Block.
         *
         * @param $autoblockIP String: the IP to autoblock.
         * @param $justInserted Boolean: the main block was just inserted
         * @return Boolean: whether or not an autoblock was inserted.
         */
        public function doAutoblock( $autoblockIP, $justInserted = false ) {
                # If autoblocks are disabled, go away.
                if ( !$this->mEnableAutoblock ) {
                        return;
                }

                # Check for presence on the autoblock whitelist
                if ( Block::isWhitelistedFromAutoblocks( $autoblockIP ) ) {
                        return;
                }

                # # Allow hooks to cancel the autoblock.
                if ( !wfRunHooks( 'AbortAutoblock', array( $autoblockIP, &$this ) ) ) {
                        wfDebug( "Autoblock aborted by hook.\n" );
                        return false;
                }

                # It's okay to autoblock. Go ahead and create/insert the block.

                $ipblock = Block::newFromDB( $autoblockIP );
                if ( $ipblock ) {
                        # If the user is already blocked. Then check if the autoblock would
                        # exceed the user block. If it would exceed, then do nothing, else
                        # prolong block time
                        if ( $this->mExpiry &&
                                ( $this->mExpiry < Block::getAutoblockExpiry( $ipblock->mTimestamp ) )
                        ) {
                                return;
                        }

                        # Just update the timestamp
                        if ( !$justInserted ) {
                                $ipblock->updateTimestamp();
                        }

                        return;
                } else {
                        $ipblock = new Block;
                }

                # Make a new block object with the desired properties
                wfDebug( "Autoblocking {$this->mAddress}@" . $autoblockIP . "\n" );
                $ipblock->mAddress = $autoblockIP;
                $ipblock->mUser = 0;
                $ipblock->mBy = $this->mBy;
                $ipblock->mByName = $this->mByName;
                $ipblock->mReason = wfMsgForContent( 'autoblocker', $this->mAddress, $this->mReason );
                $ipblock->mTimestamp = wfTimestampNow();
                $ipblock->mAuto = 1;
                $ipblock->mCreateAccount = $this->mCreateAccount;
                # Continue suppressing the name if needed
                $ipblock->mHideName = $this->mHideName;
                $ipblock->mAllowUsertalk = $this->mAllowUsertalk;

                # If the user is already blocked with an expiry date, we don't
                # want to pile on top of that!
                if ( $this->mExpiry ) {
                        $ipblock->mExpiry = min( $this->mExpiry, Block::getAutoblockExpiry( $this->mTimestamp ) );
                } else {
                        $ipblock->mExpiry = Block::getAutoblockExpiry( $this->mTimestamp );
                }

                # Insert it
                return $ipblock->insert();
        }

        /**
         * Check if a block has expired. Delete it if it is.
         * @return Boolean
         */
        public function deleteIfExpired() {
                wfProfileIn( __METHOD__ );

                if ( $this->isExpired() ) {
                        wfDebug( "Block::deleteIfExpired() -- deleting\n" );
                        $this->delete();
                        $retVal = true;
                } else {
                        wfDebug( "Block::deleteIfExpired() -- not expired\n" );
                        $retVal = false;
                }

                wfProfileOut( __METHOD__ );
                return $retVal;
        }

        /**
         * Has the block expired?
         * @return Boolean
         */
        public function isExpired() {
                wfDebug( "Block::isExpired() checking current " . wfTimestampNow() . " vs $this->mExpiry\n" );

                if ( !$this->mExpiry ) {
                        return false;
                } else {
                        return wfTimestampNow() > $this->mExpiry;
                }
        }

        /**
         * Is the block address valid (i.e. not a null string?)
         * @return Boolean
         */
        public function isValid() {
                return $this->mAddress != '';
        }

        /**
         * Update the timestamp on autoblocks.
         */
        public function updateTimestamp() {
                if ( $this->mAuto ) {
                        $this->mTimestamp = wfTimestamp();
                        $this->mExpiry = Block::getAutoblockExpiry( $this->mTimestamp );

                        $dbw = wfGetDB( DB_MASTER );
                        $dbw->update( 'ipblocks',
                                array( /* SET */
                                        'ipb_timestamp' => $dbw->timestamp( $this->mTimestamp ),
                                        'ipb_expiry' => $dbw->timestamp( $this->mExpiry ),
                                ), array( /* WHERE */
                                        'ipb_address' => $this->mAddress
                                ), 'Block::updateTimestamp'
                        );
                }
        }

        /**
         * Get the user id of the blocking sysop
         *
         * @return Integer
         */
        public function getBy() {
                return $this->mBy;
        }

        /**
         * Get the username of the blocking sysop
         *
         * @return String
         */
        public function getByName() {
                return $this->mByName;
        }

        /**
         * Get/set the SELECT ... FOR UPDATE flag
         */
        public function forUpdate( $x = null ) {
                return wfSetVar( $this->mForUpdate, $x );
        }

        /**
         * Get/set a flag determining whether the master is used for reads
         */
        public function fromMaster( $x = null ) {
                return wfSetVar( $this->mFromMaster, $x );
        }

        /**
         * Get the block name, but with autoblocked IPs hidden as per standard privacy policy
         * @return String
         */
        public function getRedactedName() {
                if ( $this->mAuto ) {
                        return '#' . $this->mId;
                } else {
                        return $this->mAddress;
                }
        }

        /**
         * Encode expiry for DB
         *
         * @param $expiry String: timestamp for expiry, or
         * @param $db Database object
         * @return String
         */
        public static function encodeExpiry( $expiry, $db ) {
                if ( $expiry == '' || $expiry == Block::infinity() ) {
                        return Block::infinity();
                } else {
                        return $db->timestamp( $expiry );
                }
        }

        /**
         * Decode expiry which has come from the DB
         *
         * @param $expiry String: Database expiry format
         * @param $timestampType Requested timestamp format
         * @return String
         */
        public static function decodeExpiry( $expiry, $timestampType = TS_MW ) {
                if ( $expiry == '' || $expiry == Block::infinity() ) {
                        return Block::infinity();
                } else {
                        return wfTimestamp( $timestampType, $expiry );
                }
        }

        /**
         * Get a timestamp of the expiry for autoblocks
         *
         * @return String
         */
        public static function getAutoblockExpiry( $timestamp ) {
                global $wgAutoblockExpiry;

                return wfTimestamp( TS_MW, wfTimestamp( TS_UNIX, $timestamp ) + $wgAutoblockExpiry );
        }

        /**
         * Gets rid of uneeded numbers in quad-dotted/octet IP strings
         * For example, 127.111.113.151/24 -> 127.111.113.0/24
         * @param $range String: IP address to normalize
         * @return string
         */
        public static function normaliseRange( $range ) {
                $parts = explode( '/', $range );
                if ( count( $parts ) == 2 ) {
                        // IPv6
                        if ( IP::isIPv6( $range ) && $parts[1] >= 64 && $parts[1] <= 128 ) {
                                $bits = $parts[1];
                                $ipint = IP::toUnsigned6( $parts[0] );
                                # Native 32 bit functions WON'T work here!!!
                                # Convert to a padded binary number
                                $network = wfBaseConvert( $ipint, 10, 2, 128 );
                                # Truncate the last (128-$bits) bits and replace them with zeros
                                $network = str_pad( substr( $network, 0, $bits ), 128, 0, STR_PAD_RIGHT );
                                # Convert back to an integer
                                $network = wfBaseConvert( $network, 2, 10 );
                                # Reform octet address
                                $newip = IP::toOctet( $network );
                                $range = "$newip/{$parts[1]}";
                        } // IPv4
                        elseif ( IP::isIPv4( $range ) && $parts[1] >= 16 && $parts[1] <= 32 ) {
                                $shift = 32 - $parts[1];
                                $ipint = IP::toUnsigned( $parts[0] );
                                $ipint = $ipint >> $shift << $shift;
                                $newip = long2ip( $ipint );
                                $range = "$newip/{$parts[1]}";
                        }
                }

                return $range;
        }

        /**
         * Purge expired blocks from the ipblocks table
         */
        public static function purgeExpired() {
                $dbw = wfGetDB( DB_MASTER );
                $dbw->delete( 'ipblocks', array( 'ipb_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ), __METHOD__ );
        }

        /**
         * Get a value to insert into expiry field of the database when infinite expiry
         * is desired. In principle this could be DBMS-dependant, but currently all
         * supported DBMS's support the string "infinity", so we just use that.
         *
         * @return String
         */
        public static function infinity() {
                # This is a special keyword for timestamps in PostgreSQL, and
                # works with CHAR(14) as well because "i" sorts after all numbers.
                return 'infinity';
        }

        /**
         * Convert a DB-encoded expiry into a real string that humans can read.
         *
         * @param $encoded_expiry String: Database encoded expiry time
         * @return Html-escaped String
         */
        public static function formatExpiry( $encoded_expiry ) {
                static $msg = null;

                if ( is_null( $msg ) ) {
                        $msg = array();
                        $keys = array( 'infiniteblock', 'expiringblock' );

                        foreach ( $keys as $key ) {
                                $msg[$key] = wfMsgHtml( $key );
                        }
                }

                $expiry = Block::decodeExpiry( $encoded_expiry );
                if ( $expiry == 'infinity' ) {
                        $expirystr = $msg['infiniteblock'];
                } else {
                        global $wgLang;
                        $expiredatestr = htmlspecialchars( $wgLang->date( $expiry, true ) );
                        $expiretimestr = htmlspecialchars( $wgLang->time( $expiry, true ) );
                        $expirystr = wfMsgReplaceArgs( $msg['expiringblock'], array( $expiredatestr, $expiretimestr ) );
                }

                return $expirystr;
        }

        /**
         * Convert a typed-in expiry time into something we can put into the database.
         * @param $expiry_input String: whatever was typed into the form
         * @return String: more database friendly
         */
        public static function parseExpiryInput( $expiry_input ) {
                if ( $expiry_input == 'infinite' || $expiry_input == 'indefinite' ) {
                        $expiry = 'infinity';
                } else {
                        $expiry = strtotime( $expiry_input );

                        if ( $expiry < 0 || $expiry === false ) {
                                return false;
                        }
                }

                return $expiry;
        }
}