JoinGroupBase.php

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<?php
 
namespace Wikimedia\Rdbms;
 
abstract class JoinGroupBase {
    protected $tables = [];
 
    protected $joinConds = [];
 
    protected $lastAlias;
 
    public function table( $table, $alias = null ) {
        if ( $table instanceof JoinGroup ) {
            $alias ??= $table->getAlias();
            $table = $table->getRawTables();
        } elseif ( $table instanceof SelectQueryBuilder ) {
            $alias ??= $this->getAutoAlias();
            $table = new Subquery( $table->getSQL() );
        } elseif ( $table instanceof Subquery ) {
            if ( $alias === null ) {
                throw new \InvalidArgumentException( __METHOD__ .
                    ': Subquery as table must provide an alias.' );
            }
        } elseif ( !is_string( $table ) ) {
            throw new \InvalidArgumentException( __METHOD__ .
                ': $table must be either string, JoinGroup or SelectQueryBuilder' );
        }
        if ( $alias === null ) {
            $this->tables[] = $table;
            $this->lastAlias = $table;
        } else {
            $this->tables[$alias] = $table;
            $this->lastAlias = $alias;
        }
        return $this;
    }
 
    public function leftJoin( $table, $alias = null, $conds = [] ) {
        $this->addJoin( 'LEFT JOIN', $table, $alias, $conds );
        return $this;
    }
 
    public function join( $table, $alias = null, $conds = [] ) {
        $this->addJoin( 'JOIN', $table, $alias, $conds );
        return $this;
    }
 
    public function straightJoin( $table, $alias = null, $conds = [] ) {
        $this->addJoin( 'STRAIGHT_JOIN', $table, $alias, $conds );
        return $this;
    }
 
    private function addJoin( $type, $table, $alias, $joinConds ) {
        if ( !$this->tables ) {
            throw new \LogicException( __METHOD__ .
                ': cannot add a join unless a regular table is added first' );
        }
        if ( $alias === null ) {
            if ( is_string( $table ) ) {
                $alias = $table;
            } else {
                $alias = $this->getAutoAlias();
            }
        }
        if ( isset( $this->joinConds[$alias] ) ) {
            throw new \LogicException( __METHOD__ .
                ": a join with alias \"$alias\" has already been added" );
        }
        if ( $table instanceof JoinGroup ) {
            $conflicts = array_intersect_key( $this->joinConds, $table->getRawJoinConds() );
            if ( $conflicts ) {
                $conflict = reset( $conflicts );
                throw new \LogicException( __METHOD__ .
                    ": a join with alias \"$conflict\" has already been added" );
            }
            $this->tables[$alias] = $table->getRawTables();
            $this->joinConds += $table->getRawJoinConds();
        } elseif ( $table instanceof SelectQueryBuilder ) {
            $this->tables[$alias] = new Subquery( $table->getSQL() );
        } elseif ( is_string( $table ) ) {
            $this->tables[$alias] = $table;
        } else {
            throw new \InvalidArgumentException( __METHOD__ .
                ': $table must be either string, JoinGroup or SelectQueryBuilder' );
        }
        $this->joinConds[$alias] = [ $type, $joinConds ];
        $this->lastAlias = $alias;
    }
 
    abstract protected function getAutoAlias();
}