Block.php

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<?php
class Block {
    public $mReason;

    public $mTimestamp;

    public $mAuto;

    public $mExpiry;

    public $mHideName;

    public $mParentBlockId;

    protected $mId;

    protected $mFromMaster;

    protected $mBlockEmail;

    protected $mDisableUsertalk;

    protected $mCreateAccount;

    protected $target;

    protected $forcedTargetID;

    protected $type;

    protected $blocker;

    protected $isHardblock = true;

    protected $isAutoblocking = true;

    # TYPE constants
    const TYPE_USER = 1;
    const TYPE_IP = 2;
    const TYPE_RANGE = 3;
    const TYPE_AUTO = 4;
    const TYPE_ID = 5;

    function __construct( $address = '', $user = 0, $by = 0, $reason = '',
        $timestamp = 0, $auto = 0, $expiry = '', $anonOnly = 0, $createAccount = 0, $enableAutoblock = 0,
        $hideName = 0, $blockEmail = 0, $allowUsertalk = 0, $byText = ''
    ) {
        if ( $timestamp === 0 ) {
            $timestamp = wfTimestampNow();
        }

        if ( count( func_get_args() ) > 0 ) {
            # Soon... :D
            # wfDeprecated( __METHOD__ . " with arguments" );
        }

        $this->setTarget( $address );
        if ( $this->target instanceof User && $user ) {
            $this->forcedTargetID = $user; // needed for foreign users
        }
        if ( $by ) { // local user
            $this->setBlocker( User::newFromID( $by ) );
        } else { // foreign user
            $this->setBlocker( $byText );
        }
        $this->mReason = $reason;
        $this->mTimestamp = wfTimestamp( TS_MW, $timestamp );
        $this->mAuto = $auto;
        $this->isHardblock( !$anonOnly );
        $this->prevents( 'createaccount', $createAccount );
        if ( $expiry == 'infinity' || $expiry == wfGetDB( DB_SLAVE )->getInfinity() ) {
            $this->mExpiry = 'infinity';
        } else {
            $this->mExpiry = wfTimestamp( TS_MW, $expiry );
        }
        $this->isAutoblocking( $enableAutoblock );
        $this->mHideName = $hideName;
        $this->prevents( 'sendemail', $blockEmail );
        $this->prevents( 'editownusertalk', !$allowUsertalk );

        $this->mFromMaster = false;
    }

    public static function newFromID( $id ) {
        $dbr = wfGetDB( DB_SLAVE );
        $res = $dbr->selectRow(
            'ipblocks',
            self::selectFields(),
            array( 'ipb_id' => $id ),
            __METHOD__
        );
        if ( $res ) {
            return self::newFromRow( $res );
        } else {
            return null;
        }
    }

    public static function selectFields() {
        return array(
            'ipb_id',
            'ipb_address',
            'ipb_by',
            'ipb_by_text',
            'ipb_reason',
            'ipb_timestamp',
            'ipb_auto',
            'ipb_anon_only',
            'ipb_create_account',
            'ipb_enable_autoblock',
            'ipb_expiry',
            'ipb_deleted',
            'ipb_block_email',
            'ipb_allow_usertalk',
            'ipb_parent_block_id',
        );
    }

    public function equals( Block $block ) {
        return (
            (string)$this->target == (string)$block->target
            && $this->type == $block->type
            && $this->mAuto == $block->mAuto
            && $this->isHardblock() == $block->isHardblock()
            && $this->prevents( 'createaccount' ) == $block->prevents( 'createaccount' )
            && $this->mExpiry == $block->mExpiry
            && $this->isAutoblocking() == $block->isAutoblocking()
            && $this->mHideName == $block->mHideName
            && $this->prevents( 'sendemail' ) == $block->prevents( 'sendemail' )
            && $this->prevents( 'editownusertalk' ) == $block->prevents( 'editownusertalk' )
            && $this->mReason == $block->mReason
        );
    }

    protected function newLoad( $vagueTarget = null ) {
        $db = wfGetDB( $this->mFromMaster ? DB_MASTER : DB_SLAVE );

        if ( $this->type !== null ) {
            $conds = array(
                'ipb_address' => array( (string)$this->target ),
            );
        } else {
            $conds = array( 'ipb_address' => array() );
        }

        # Be aware that the != '' check is explicit, since empty values will be
        # passed by some callers (bug 29116)
        if ( $vagueTarget != '' ) {
            list( $target, $type ) = self::parseTarget( $vagueTarget );
            switch ( $type ) {
                case self::TYPE_USER:
                    # Slightly weird, but who are we to argue?
                    $conds['ipb_address'][] = (string)$target;
                    break;

                case self::TYPE_IP:
                    $conds['ipb_address'][] = (string)$target;
                    $conds[] = self::getRangeCond( IP::toHex( $target ) );
                    $conds = $db->makeList( $conds, LIST_OR );
                    break;

                case self::TYPE_RANGE:
                    list( $start, $end ) = IP::parseRange( $target );
                    $conds['ipb_address'][] = (string)$target;
                    $conds[] = self::getRangeCond( $start, $end );
                    $conds = $db->makeList( $conds, LIST_OR );
                    break;

                default:
                    throw new MWException( "Tried to load block with invalid type" );
            }
        }

        $res = $db->select( 'ipblocks', self::selectFields(), $conds, __METHOD__ );

        # This result could contain a block on the user, a block on the IP, and a russian-doll
        # set of rangeblocks.  We want to choose the most specific one, so keep a leader board.
        $bestRow = null;

        # Lower will be better
        $bestBlockScore = 100;

        # This is begging for $this = $bestBlock, but that's not allowed in PHP :(
        $bestBlockPreventsEdit = null;

        foreach ( $res as $row ) {
            $block = self::newFromRow( $row );

            # Don't use expired blocks
            if ( $block->deleteIfExpired() ) {
                continue;
            }

            # Don't use anon only blocks on users
            if ( $this->type == self::TYPE_USER && !$block->isHardblock() ) {
                continue;
            }

            if ( $block->getType() == self::TYPE_RANGE ) {
                # This is the number of bits that are allowed to vary in the block, give
                # or take some floating point errors
                $end = wfBaseconvert( $block->getRangeEnd(), 16, 10 );
                $start = wfBaseconvert( $block->getRangeStart(), 16, 10 );
                $size = log( $end - $start + 1, 2 );

                # This has the nice property that a /32 block is ranked equally with a
                # single-IP block, which is exactly what it is...
                $score = self::TYPE_RANGE - 1 + ( $size / 128 );

            } else {
                $score = $block->getType();
            }

            if ( $score < $bestBlockScore ) {
                $bestBlockScore = $score;
                $bestRow = $row;
                $bestBlockPreventsEdit = $block->prevents( 'edit' );
            }
        }

        if ( $bestRow !== null ) {
            $this->initFromRow( $bestRow );
            $this->prevents( 'edit', $bestBlockPreventsEdit );
            return true;
        } else {
            return false;
        }
    }

    public static function getRangeCond( $start, $end = null ) {
        if ( $end === null ) {
            $end = $start;
        }
        # Per bug 14634, we want to include relevant active rangeblocks; for
        # rangeblocks, we want to include larger ranges which enclose the given
        # range. We know that all blocks must be smaller than $wgBlockCIDRLimit,
        # so we can improve performance by filtering on a LIKE clause
        $chunk = self::getIpFragment( $start );
        $dbr = wfGetDB( DB_SLAVE );
        $like = $dbr->buildLike( $chunk, $dbr->anyString() );

        # Fairly hard to make a malicious SQL statement out of hex characters,
        # but stranger things have happened...
        $safeStart = $dbr->addQuotes( $start );
        $safeEnd = $dbr->addQuotes( $end );

        return $dbr->makeList(
            array(
                "ipb_range_start $like",
                "ipb_range_start <= $safeStart",
                "ipb_range_end >= $safeEnd",
            ),
            LIST_AND
        );
    }

    protected static function getIpFragment( $hex ) {
        global $wgBlockCIDRLimit;
        if ( substr( $hex, 0, 3 ) == 'v6-' ) {
            return 'v6-' . substr( substr( $hex, 3 ), 0, floor( $wgBlockCIDRLimit['IPv6'] / 4 ) );
        } else {
            return substr( $hex, 0, floor( $wgBlockCIDRLimit['IPv4'] / 4 ) );
        }
    }

    protected function initFromRow( $row ) {
        $this->setTarget( $row->ipb_address );
        if ( $row->ipb_by ) { // local user
            $this->setBlocker( User::newFromID( $row->ipb_by ) );
        } else { // foreign user
            $this->setBlocker( $row->ipb_by_text );
        }

        $this->mReason = $row->ipb_reason;
        $this->mTimestamp = wfTimestamp( TS_MW, $row->ipb_timestamp );
        $this->mAuto = $row->ipb_auto;
        $this->mHideName = $row->ipb_deleted;
        $this->mId = $row->ipb_id;
        $this->mParentBlockId = $row->ipb_parent_block_id;

        // I wish I didn't have to do this
        $db = wfGetDB( DB_SLAVE );
        if ( $row->ipb_expiry == $db->getInfinity() ) {
            $this->mExpiry = 'infinity';
        } else {
            $this->mExpiry = wfTimestamp( TS_MW, $row->ipb_expiry );
        }

        $this->isHardblock( !$row->ipb_anon_only );
        $this->isAutoblocking( $row->ipb_enable_autoblock );

        $this->prevents( 'createaccount', $row->ipb_create_account );
        $this->prevents( 'sendemail', $row->ipb_block_email );
        $this->prevents( 'editownusertalk', !$row->ipb_allow_usertalk );
    }

    public static function newFromRow( $row ) {
        $block = new Block;
        $block->initFromRow( $row );
        return $block;
    }

    public function delete() {
        if ( wfReadOnly() ) {
            return false;
        }

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

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

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

    public function insert( $dbw = null ) {
        wfDebug( "Block::insert; timestamp {$this->mTimestamp}\n" );

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

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

        $row = $this->getDatabaseArray();
        $row['ipb_id'] = $dbw->nextSequenceValue( "ipblocks_ipb_id_seq" );

        $dbw->insert(
            'ipblocks',
            $row,
            __METHOD__,
            array( 'IGNORE' )
        );
        $affected = $dbw->affectedRows();
        $this->mId = $dbw->insertId();

        if ( $affected ) {
            $auto_ipd_ids = $this->doRetroactiveAutoblock();
            return array( 'id' => $this->mId, 'autoIds' => $auto_ipd_ids );
        }

        return false;
    }

    public function update() {
        wfDebug( "Block::update; timestamp {$this->mTimestamp}\n" );
        $dbw = wfGetDB( DB_MASTER );

        $dbw->startAtomic( __METHOD__ );

        $dbw->update(
            'ipblocks',
            $this->getDatabaseArray( $dbw ),
            array( 'ipb_id' => $this->getId() ),
            __METHOD__
        );

        $affected = $dbw->affectedRows();

        if ( $this->isAutoblocking() ) {
            // update corresponding autoblock(s) (bug 48813)
            $dbw->update(
                'ipblocks',
                $this->getAutoblockUpdateArray(),
                array( 'ipb_parent_block_id' => $this->getId() ),
                __METHOD__
            );
        } else {
            // autoblock no longer required, delete corresponding autoblock(s)
            $dbw->delete(
                'ipblocks',
                array( 'ipb_parent_block_id' => $this->getId() ),
                __METHOD__
            );
        }

        $dbw->endAtomic( __METHOD__ );

        if ( $affected ) {
            $auto_ipd_ids = $this->doRetroactiveAutoblock();
            return array( 'id' => $this->mId, 'autoIds' => $auto_ipd_ids );
        }

        return false;
    }

    protected function getDatabaseArray( $db = null ) {
        if ( !$db ) {
            $db = wfGetDB( DB_SLAVE );
        }
        $expiry = $db->encodeExpiry( $this->mExpiry );

        if ( $this->forcedTargetID ) {
            $uid = $this->forcedTargetID;
        } else {
            $uid = $this->target instanceof User ? $this->target->getID() : 0;
        }

        $a = array(
            'ipb_address'          => (string)$this->target,
            'ipb_user'             => $uid,
            'ipb_by'               => $this->getBy(),
            'ipb_by_text'          => $this->getByName(),
            'ipb_reason'           => $this->mReason,
            'ipb_timestamp'        => $db->timestamp( $this->mTimestamp ),
            'ipb_auto'             => $this->mAuto,
            'ipb_anon_only'        => !$this->isHardblock(),
            'ipb_create_account'   => $this->prevents( 'createaccount' ),
            'ipb_enable_autoblock' => $this->isAutoblocking(),
            'ipb_expiry'           => $expiry,
            'ipb_range_start'      => $this->getRangeStart(),
            'ipb_range_end'        => $this->getRangeEnd(),
            'ipb_deleted'          => intval( $this->mHideName ), // typecast required for SQLite
            'ipb_block_email'      => $this->prevents( 'sendemail' ),
            'ipb_allow_usertalk'   => !$this->prevents( 'editownusertalk' ),
            'ipb_parent_block_id'  => $this->mParentBlockId
        );

        return $a;
    }

    protected function getAutoblockUpdateArray() {
        return array(
            'ipb_by'               => $this->getBy(),
            'ipb_by_text'          => $this->getByName(),
            'ipb_reason'           => $this->mReason,
            'ipb_create_account'   => $this->prevents( 'createaccount' ),
            'ipb_deleted'          => (int)$this->mHideName, // typecast required for SQLite
            'ipb_allow_usertalk'   => !$this->prevents( 'editownusertalk' ),
        );
    }

    protected function doRetroactiveAutoblock() {
        $blockIds = array();
        # If autoblock is enabled, autoblock the LAST IP(s) used
        if ( $this->isAutoblocking() && $this->getType() == self::TYPE_USER ) {
            wfDebug( "Doing retroactive autoblocks for " . $this->getTarget() . "\n" );

            $continue = wfRunHooks(
                'PerformRetroactiveAutoblock', array( $this, &$blockIds ) );

            if ( $continue ) {
                self::defaultRetroactiveAutoblock( $this, $blockIds );
            }
        }
        return $blockIds;
    }

    protected static function defaultRetroactiveAutoblock( Block $block, array &$blockIds ) {
        global $wgPutIPinRC;

        // No IPs are in recentchanges table, so nothing to select
        if ( !$wgPutIPinRC ) {
            return;
        }

        $dbr = wfGetDB( DB_SLAVE );

        $options = array( 'ORDER BY' => 'rc_timestamp DESC' );
        $conds = array( 'rc_user_text' => (string)$block->getTarget() );

        // Just the last IP used.
        $options['LIMIT'] = 1;

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

        if ( !$res->numRows() ) {
            # No results, don't autoblock anything
            wfDebug( "No IP found to retroactively autoblock\n" );
        } else {
            foreach ( $res as $row ) {
                if ( $row->rc_ip ) {
                    $id = $block->doAutoblock( $row->rc_ip );
                    if ( $id ) {
                        $blockIds[] = $id;
                    }
                }
            }
        }
    }

    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", wfMessage( 'autoblock_whitelist' )->inContentLanguage()->plain() );
            $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;
    }

    public function doAutoblock( $autoblockIP ) {
        # If autoblocks are disabled, go away.
        if ( !$this->isAutoblocking() ) {
            return false;
        }

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

        # 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 insert/update the block...

        # Do not add a *new* block if the IP is already blocked.
        $ipblock = Block::newFromTarget( $autoblockIP );
        if ( $ipblock ) {
            # Check if the block is an autoblock and would exceed the user block
            # if renewed. If so, do nothing, otherwise prolong the block time...
            if ( $ipblock->mAuto && // @todo Why not compare $ipblock->mExpiry?
                $this->mExpiry > Block::getAutoblockExpiry( $ipblock->mTimestamp )
            ) {
                # Reset block timestamp to now and its expiry to
                # $wgAutoblockExpiry in the future
                $ipblock->updateTimestamp();
            }
            return false;
        }

        # Make a new block object with the desired properties.
        $autoblock = new Block;
        wfDebug( "Autoblocking {$this->getTarget()}@" . $autoblockIP . "\n" );
        $autoblock->setTarget( $autoblockIP );
        $autoblock->setBlocker( $this->getBlocker() );
        $autoblock->mReason = wfMessage( 'autoblocker', $this->getTarget(), $this->mReason )
            ->inContentLanguage()->plain();
        $timestamp = wfTimestampNow();
        $autoblock->mTimestamp = $timestamp;
        $autoblock->mAuto = 1;
        $autoblock->prevents( 'createaccount', $this->prevents( 'createaccount' ) );
        # Continue suppressing the name if needed
        $autoblock->mHideName = $this->mHideName;
        $autoblock->prevents( 'editownusertalk', $this->prevents( 'editownusertalk' ) );
        $autoblock->mParentBlockId = $this->mId;

        if ( $this->mExpiry == 'infinity' ) {
            # Original block was indefinite, start an autoblock now
            $autoblock->mExpiry = Block::getAutoblockExpiry( $timestamp );
        } else {
            # If the user is already blocked with an expiry date, we don't
            # want to pile on top of that.
            $autoblock->mExpiry = min( $this->mExpiry, Block::getAutoblockExpiry( $timestamp ) );
        }

        # Insert the block...
        $status = $autoblock->insert();
        return $status
            ? $status['id']
            : false;
    }

    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;
    }

    public function isExpired() {
        $timestamp = wfTimestampNow();
        wfDebug( "Block::isExpired() checking current " . $timestamp . " vs $this->mExpiry\n" );

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

    public function isValid() {
        return $this->getTarget() != null;
    }

    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( $this->mExpiry ),
                ),
                array( /* WHERE */
                    'ipb_address' => (string)$this->getTarget()
                ),
                __METHOD__
            );
        }
    }

    public function getRangeStart() {
        switch ( $this->type ) {
            case self::TYPE_USER:
                return '';
            case self::TYPE_IP:
                return IP::toHex( $this->target );
            case self::TYPE_RANGE:
                list( $start, /*...*/ ) = IP::parseRange( $this->target );
                return $start;
            default:
                throw new MWException( "Block with invalid type" );
        }
    }

    public function getRangeEnd() {
        switch ( $this->type ) {
            case self::TYPE_USER:
                return '';
            case self::TYPE_IP:
                return IP::toHex( $this->target );
            case self::TYPE_RANGE:
                list( /*...*/, $end ) = IP::parseRange( $this->target );
                return $end;
            default:
                throw new MWException( "Block with invalid type" );
        }
    }

    public function getBy() {
        $blocker = $this->getBlocker();
        return ( $blocker instanceof User )
            ? $blocker->getId()
            : 0;
    }

    public function getByName() {
        $blocker = $this->getBlocker();
        return ( $blocker instanceof User )
            ? $blocker->getName()
            : (string)$blocker; // username
    }

    public function getId() {
        return $this->mId;
    }

    public function fromMaster( $x = null ) {
        return wfSetVar( $this->mFromMaster, $x );
    }

    public function isHardblock( $x = null ) {
        wfSetVar( $this->isHardblock, $x );

        # You can't *not* hardblock a user
        return $this->getType() == self::TYPE_USER
            ? true
            : $this->isHardblock;
    }

    public function isAutoblocking( $x = null ) {
        wfSetVar( $this->isAutoblocking, $x );

        # You can't put an autoblock on an IP or range as we don't have any history to
        # look over to get more IPs from
        return $this->getType() == self::TYPE_USER
            ? $this->isAutoblocking
            : false;
    }

    public function prevents( $action, $x = null ) {
        switch ( $action ) {
            case 'edit':
                # For now... <evil laugh>
                return true;

            case 'createaccount':
                return wfSetVar( $this->mCreateAccount, $x );

            case 'sendemail':
                return wfSetVar( $this->mBlockEmail, $x );

            case 'editownusertalk':
                return wfSetVar( $this->mDisableUsertalk, $x );

            default:
                return null;
        }
    }

    public function getRedactedName() {
        if ( $this->mAuto ) {
            return Html::rawElement(
                'span',
                array( 'class' => 'mw-autoblockid' ),
                wfMessage( 'autoblockid', $this->mId )
            );
        } else {
            return htmlspecialchars( $this->getTarget() );
        }
    }

    public static function getAutoblockExpiry( $timestamp ) {
        global $wgAutoblockExpiry;

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

    public static function purgeExpired() {
        if ( wfReadOnly() ) {
            return;
        }

        $method = __METHOD__;
        $dbw = wfGetDB( DB_MASTER );
        $dbw->onTransactionIdle( function () use ( $dbw, $method ) {
            $dbw->delete( 'ipblocks',
                array( 'ipb_expiry < ' . $dbw->addQuotes( $dbw->timestamp() ) ), $method );
        } );
    }

    public static function newFromTarget( $specificTarget, $vagueTarget = null, $fromMaster = false ) {

        list( $target, $type ) = self::parseTarget( $specificTarget );
        if ( $type == Block::TYPE_ID || $type == Block::TYPE_AUTO ) {
            return Block::newFromID( $target );

        } elseif ( $target === null && $vagueTarget == '' ) {
            # We're not going to find anything useful here
            # Be aware that the == '' check is explicit, since empty values will be
            # passed by some callers (bug 29116)
            return null;

        } elseif ( in_array(
            $type,
            array( Block::TYPE_USER, Block::TYPE_IP, Block::TYPE_RANGE, null ) )
        ) {
            $block = new Block();
            $block->fromMaster( $fromMaster );

            if ( $type !== null ) {
                $block->setTarget( $target );
            }

            if ( $block->newLoad( $vagueTarget ) ) {
                return $block;
            }
        }
        return null;
    }

    public static function getBlocksForIPList( array $ipChain, $isAnon, $fromMaster = false ) {
        if ( !count( $ipChain ) ) {
            return array();
        }

        wfProfileIn( __METHOD__ );
        $conds = array();
        foreach ( array_unique( $ipChain ) as $ipaddr ) {
            # Discard invalid IP addresses. Since XFF can be spoofed and we do not
            # necessarily trust the header given to us, make sure that we are only
            # checking for blocks on well-formatted IP addresses (IPv4 and IPv6).
            # Do not treat private IP spaces as special as it may be desirable for wikis
            # to block those IP ranges in order to stop misbehaving proxies that spoof XFF.
            if ( !IP::isValid( $ipaddr ) ) {
                continue;
            }
            # Don't check trusted IPs (includes local squids which will be in every request)
            if ( IP::isTrustedProxy( $ipaddr ) ) {
                continue;
            }
            # Check both the original IP (to check against single blocks), as well as build
            # the clause to check for rangeblocks for the given IP.
            $conds['ipb_address'][] = $ipaddr;
            $conds[] = self::getRangeCond( IP::toHex( $ipaddr ) );
        }

        if ( !count( $conds ) ) {
            wfProfileOut( __METHOD__ );
            return array();
        }

        if ( $fromMaster ) {
            $db = wfGetDB( DB_MASTER );
        } else {
            $db = wfGetDB( DB_SLAVE );
        }
        $conds = $db->makeList( $conds, LIST_OR );
        if ( !$isAnon ) {
            $conds = array( $conds, 'ipb_anon_only' => 0 );
        }
        $selectFields = array_merge(
            array( 'ipb_range_start', 'ipb_range_end' ),
            Block::selectFields()
        );
        $rows = $db->select( 'ipblocks',
            $selectFields,
            $conds,
            __METHOD__
        );

        $blocks = array();
        foreach ( $rows as $row ) {
            $block = self::newFromRow( $row );
            if ( !$block->deleteIfExpired()  ) {
                $blocks[] = $block;
            }
        }

        wfProfileOut( __METHOD__ );
        return $blocks;
    }

    public static function chooseBlock( array $blocks, array $ipChain ) {
        if ( !count( $blocks ) ) {
            return null;
        } elseif ( count( $blocks ) == 1 ) {
            return $blocks[0];
        }

        wfProfileIn( __METHOD__ );

        // Sort hard blocks before soft ones and secondarily sort blocks
        // that disable account creation before those that don't.
        usort( $blocks, function ( Block $a, Block $b ) {
            $aWeight = (int)$a->isHardblock() . (int)$a->prevents( 'createaccount' );
            $bWeight = (int)$b->isHardblock() . (int)$b->prevents( 'createaccount' );
            return strcmp( $bWeight, $aWeight ); // highest weight first
        } );

        $blocksListExact = array(
            'hard' => false,
            'disable_create' => false,
            'other' => false,
            'auto' => false
        );
        $blocksListRange = array(
            'hard' => false,
            'disable_create' => false,
            'other' => false,
            'auto' => false
        );
        $ipChain = array_reverse( $ipChain );

        foreach ( $blocks as $block ) {
            // Stop searching if we have already have a "better" block. This
            // is why the order of the blocks matters
            if ( !$block->isHardblock() && $blocksListExact['hard'] ) {
                break;
            } elseif ( !$block->prevents( 'createaccount' ) && $blocksListExact['disable_create'] ) {
                break;
            }

            foreach ( $ipChain as $checkip ) {
                $checkipHex = IP::toHex( $checkip );
                if ( (string)$block->getTarget() === $checkip ) {
                    if ( $block->isHardblock() ) {
                        $blocksListExact['hard'] = $blocksListExact['hard'] ?: $block;
                    } elseif ( $block->prevents( 'createaccount' ) ) {
                        $blocksListExact['disable_create'] = $blocksListExact['disable_create'] ?: $block;
                    } elseif ( $block->mAuto ) {
                        $blocksListExact['auto'] = $blocksListExact['auto'] ?: $block;
                    } else {
                        $blocksListExact['other'] = $blocksListExact['other'] ?: $block;
                    }
                    // We found closest exact match in the ip list, so go to the next Block
                    break;
                } elseif ( array_filter( $blocksListExact ) == array()
                    && $block->getRangeStart() <= $checkipHex
                    && $block->getRangeEnd() >= $checkipHex
                ) {
                    if ( $block->isHardblock() ) {
                        $blocksListRange['hard'] = $blocksListRange['hard'] ?: $block;
                    } elseif ( $block->prevents( 'createaccount' ) ) {
                        $blocksListRange['disable_create'] = $blocksListRange['disable_create'] ?: $block;
                    } elseif ( $block->mAuto ) {
                        $blocksListRange['auto'] = $blocksListRange['auto'] ?: $block;
                    } else {
                        $blocksListRange['other'] = $blocksListRange['other'] ?: $block;
                    }
                    break;
                }
            }
        }

        if ( array_filter( $blocksListExact ) == array() ) {
            $blocksList = &$blocksListRange;
        } else {
            $blocksList = &$blocksListExact;
        }

        $chosenBlock = null;
        if ( $blocksList['hard'] ) {
            $chosenBlock = $blocksList['hard'];
        } elseif ( $blocksList['disable_create'] ) {
            $chosenBlock = $blocksList['disable_create'];
        } elseif ( $blocksList['other'] ) {
            $chosenBlock = $blocksList['other'];
        } elseif ( $blocksList['auto'] ) {
            $chosenBlock = $blocksList['auto'];
        } else {
            wfProfileOut( __METHOD__ );
            throw new MWException( "Proxy block found, but couldn't be classified." );
        }

        wfProfileOut( __METHOD__ );
        return $chosenBlock;
    }

    public static function parseTarget( $target ) {
        # We may have been through this before
        if ( $target instanceof User ) {
            if ( IP::isValid( $target->getName() ) ) {
                return array( $target, self::TYPE_IP );
            } else {
                return array( $target, self::TYPE_USER );
            }
        } elseif ( $target === null ) {
            return array( null, null );
        }

        $target = trim( $target );

        if ( IP::isValid( $target ) ) {
            # We can still create a User if it's an IP address, but we need to turn
            # off validation checking (which would exclude IP addresses)
            return array(
                User::newFromName( IP::sanitizeIP( $target ), false ),
                Block::TYPE_IP
            );

        } elseif ( IP::isValidBlock( $target ) ) {
            # Can't create a User from an IP range
            return array( IP::sanitizeRange( $target ), Block::TYPE_RANGE );
        }

        # Consider the possibility that this is not a username at all
        # but actually an old subpage (bug #29797)
        if ( strpos( $target, '/' ) !== false ) {
            # An old subpage, drill down to the user behind it
            $parts = explode( '/', $target );
            $target = $parts[0];
        }

        $userObj = User::newFromName( $target );
        if ( $userObj instanceof User ) {
            # Note that since numbers are valid usernames, a $target of "12345" will be
            # considered a User.  If you want to pass a block ID, prepend a hash "#12345",
            # since hash characters are not valid in usernames or titles generally.
            return array( $userObj, Block::TYPE_USER );

        } elseif ( preg_match( '/^#\d+$/', $target ) ) {
            # Autoblock reference in the form "#12345"
            return array( substr( $target, 1 ), Block::TYPE_AUTO );

        } else {
            # WTF?
            return array( null, null );
        }
    }

    public function getType() {
        return $this->mAuto
            ? self::TYPE_AUTO
            : $this->type;
    }

    public function getTargetAndType() {
        return array( $this->getTarget(), $this->getType() );
    }

    public function getTarget() {
        return $this->target;
    }

    public function getExpiry() {
        return $this->mExpiry;
    }

    public function setTarget( $target ) {
        list( $this->target, $this->type ) = self::parseTarget( $target );
    }

    public function getBlocker() {
        return $this->blocker;
    }

    public function setBlocker( $user ) {
        $this->blocker = $user;
    }

    public function getPermissionsError( IContextSource $context ) {
        $blocker = $this->getBlocker();
        if ( $blocker instanceof User ) { // local user
            $blockerUserpage = $blocker->getUserPage();
            $link = "[[{$blockerUserpage->getPrefixedText()}|{$blockerUserpage->getText()}]]";
        } else { // foreign user
            $link = $blocker;
        }

        $reason = $this->mReason;
        if ( $reason == '' ) {
            $reason = $context->msg( 'blockednoreason' )->text();
        }

        /* $ip returns who *is* being blocked, $intended contains who was meant to be blocked.
         * This could be a username, an IP range, or a single IP. */
        $intended = $this->getTarget();

        $lang = $context->getLanguage();
        return array(
            $this->mAuto ? 'autoblockedtext' : 'blockedtext',
            $link,
            $reason,
            $context->getRequest()->getIP(),
            $this->getByName(),
            $this->getId(),
            $lang->formatExpiry( $this->mExpiry ),
            (string)$intended,
            $lang->userTimeAndDate( $this->mTimestamp, $context->getUser() ),
        );
    }
}