expr.inc.php

PHP 知识管理系统（基于树结构的知识管理系统）, 英文原版的PHP源码。

	        	if ($this->isDBonly() || $this->isTextOnly())
        		{
					$this->clearPoint();
					$point = 'point';
        		}
        	}
        }

        if ($point == 'point')
        {
			if ($this->isDBandText())
			{
				$point = 'merge';
				$left->setPoint('point');
				$right->setPoint('point');
			}
        }
        if (is_null($point) && !DefaultOpCollection::isBoolean($op))
        {
        	$point = 'point';
        }

		$this->setPoint($point);
    }

    private function isDBonly()
    {
    	return $this->getHasDb() && !$this->getHasText();
    }

    private function isTextOnly()
    {
    	return !$this->getHasDb() && $this->getHasText();
    }

    private function isDBandText()
    {
    	return $this->getHasDb() && $this->getHasText();
    }

    public function appliesToContext()
    {
        return $this->left()->appliesToContext() | $this->right()->appliesToContext();
    }

    /**
     * Enter description here...
     *
     * @param OpExpr $expr
     */
    protected  function clearPoint()
    {
    	if (DefaultOpCollection::isBoolean($this))
    	{
			$this->left()->clearPoint();
			$this->right()->clearPoint();
    	}
    	if ($this->isMergePoint())
    	{
    		$this->setPoint(null);
    	}
    }


    protected function isMergePoint()
    {
    	return in_array($this->getPoint(), array('merge','point'));
    }

    /**
     * Returns the operator on the expression
     *
     * @return ExprOp
     */
    public function op()
    {
        return $this->op;
    }

    /**
     * Returns true if the negative of the operator should be used in evaluation
     *
     * @param boolean $not
     * @return boolean
     */
    public function not($not=null)
    {
        if (!is_null($not))
        {
            $this->not = $not;
        }

        return $this->not;
    }

    /**
     * The left side of the  expression
     *
     * @return Expr
     */
    public function &left()
    {
        return $this->left_expr;
    }

    /**
     * The right side of the  expression
     *
     * @return Expr
     */
    public function &right()
    {
        return $this->right_expr;
    }

    /**
     * Converts the expression to a string
     *
     * @return string
     */
    public function __toString()
    {
        // _kt may not translate well here.
        $expr = $this->left_expr . ' ' . _kt($this->op) .' ' .  $this->right_expr;

        if (is_null($this->parent))
        {
        	if ($this->not())
        	{
            	 $expr = _kt('NOT') . $expr;
        	}
            return $expr;
        }

        if ($this->parent->isOpExpr())
        {
            if ($this->parent->op != $this->op && in_array($this->op, DefaultOpCollection::$boolean))
            {
                 $expr = "($expr)";
            }
        }

        if ($this->not())
        {
             $expr = "!($expr)";
        }

        return $expr;
    }

    /**
     * Is the expression valid
     *
     * @return boolean
     */
    public function is_valid()
    {
        $left = $this->left();
        $right = $this->right();
        return $left->is_valid() && $right->is_valid();
    }

    /**
     * Finds the results that are in both record sets.
     *
     * @param array $leftres
     * @param array $rightres
     * @return array
     */
	protected static function _intersect($leftres, $rightres)
    {
    	if (empty($leftres) || empty($rightres))
    	{
    		return array(); // small optimisation
    	}
    	$result = array();
    	foreach($leftres as $item)
    	{
    		$document_id = $item->Id;

    		if (!$item->IsLive)
    		{
    			continue;
    		}

    		if (array_key_exists($document_id, $rightres))
    		{
    			$check = $rightres[$document_id];

    			$result[$document_id] = ($item->Rank < $check->Rank)?$check:$item;
    		}
    	}
    	return $result;
    }

	protected static function intersect($leftres, $rightres)
    {
        return array(
            'docs'=>self::_intersect($leftres['docs'],$rightres['docs']),
            'folders'=>self::_intersect($leftres['folders'],$rightres['folders'])
        );
    }

	protected static function union($leftres, $rightres)
    {
        return array(
            'docs'=>self::_union($leftres['docs'],$rightres['docs']),
            'folders'=>self::_union($leftres['folders'],$rightres['folders'])
        );
    }

    /**
     * The objective of this function is to merge the results so that there is a union of the results,
     * but there should be no duplicates.
     *
     * @param array $leftres
     * @param array $rightres
     * @return array
     */
    protected static function _union($leftres, $rightres)
    {
    	if (empty($leftres))
    	{
    		return $rightres; // small optimisation
    	}
    	if (empty($rightres))
    	{
    		return $leftres; // small optimisation
    	}
    	$result = array();

    	foreach($leftres as $item)
    	{
			if ($item->IsLive)
    		{
    			$result[$item->Id] = $item;
    		}
    	}

    	foreach($rightres as $item)
    	{
    		if (!array_key_exists($item->Id, $result) || $item->Rank > $result[$item->Id]->Rank)
    		{
    			$result[$item->Id] = $item;
    		}
    	}
    	return $result;
    }

    /**
     * Enter description here...
     *
     * @param OpExpr $left
     * @param ExprOp $op
     * @param OpExpr $right
     * @param boolean $not
     */
    public function transform(& $left, & $op, & $right, & $not)
    {

    	if (!$left->isOpExpr() || !$right->isOpExpr() || !DefaultOpCollection::isBoolean($op))
    	{
    		return;
    	}

		if ($left->isTextOnly() && $right->isDBonly())
		{
			// we just swap the items around, to ease other transformations
			$tmp = $left;
			$left = $right;
			$right = $tmp;
			return;
		}

		if ($op != $right->op() || !DefaultOpCollection::isBoolean($right))
		{
			return;
		}

		if ($op == ExprOp::OP_OR && ($not || $right->not()))
		{
			// NOTE: we can't transform. e.g.
			// db or !(db or txt) => db or !db and !txt
			// so nothing to do

			// BUT: db and !(db and txt) => db and !db and !txt
			return;
		}

		$rightLeft = $right->left();
		$rightRight = $right->right();

		if ($left->isDBonly() && $rightLeft->isDBonly())
		{
			$newLeft = new OpExpr( $left, $op, $rightLeft );

			$right = $rightRight;
			$left = $newLeft;
			return;
		}

		if ($left->isTextOnly() && $rightRight->isTextOnly())
		{
			$newRight = new OpExpr($left, $op, $rightRight);
			$left = $rightLeft;
			$right = $newRight;
			return;
		}

    }

    private function findDBNode($start, $op, $what)
    {
    	if ($start->op() != $op)
    	{
    		return null;
    	}
    	switch($what)
    	{
    		case 'db':
    			if ($start->isDBonly())
    			{
    				return $start;
    			}
    			break;
    		case 'txt':
    			if ($start->isTextOnly())
    			{
    				return $start;
    			}
    			break;
    	}
    	$node = $this->findDBNode($start->left(), $op, $what);
    	if (is_null($left))
    	{
    		$node = $this->findDBNode($start->right(), $op, $what);
    	}
    	return $node;

    }

    public function traverse($object, $method, $param)
    {
    	if ($this->isOpExpr())
    	{
	    	$object->$method($param);
    	}
    }

    private function exploreItem($item, & $group, $interest)
    {
    	if (($interest == 'db' && $item->getHasDb()) ||
    		($interest == 'text' && $item->getHasText()))
    	{
			if (in_array($item->op(), array(ExprOp::OP_OR, ExprOp::OP_AND)))
			{
				$this->exploreItem($item->left(),  $group, $interest);
				$this->exploreItem($item->right(),  $group, $interest);
			}
			else
			{
				$group[] = $item;
			}
    	}
    }

    private function explore($left, $right, & $group, $interest)
    {
		$this->exploreItem($left,  $group, $interest);
		$this->exploreItem($right,  $group, $interest);
    }

    private function exec_db_query($op, $group)
    {
    	if (empty($group)) { return array(); }

    	$exprbuilder = new SQLQueryBuilder($this->getContext());

    	if (count($group) == 1)
    	{
    		$sql = $exprbuilder->buildComplexQuery($group[0]);
    	}
    	else
    	{
			$sql = $exprbuilder->buildSimpleQuery($op, $group);
    	}

    	if (empty($sql))
    	{
    	    return array();
    	}

    	$results = array();
    	global $default;
    	$default->log->debug("SEARCH SQL: $sql");
    	$rs = DBUtil::getResultArray($sql);

    	if (PEAR::isError($rs))
    	{
    		throw new Exception($rs->getMessage());
    	}

    	foreach($rs as $item)
    	{
    		$id = $item['id'];
    		$rank = $exprbuilder->getRanking($item);
    		if (!array_key_exists($id, $results) || $rank > $results[$id]->Rank)
    		{
    		    if ($this->context == ExprContext::DOCUMENT)
    		    {
    		        $results[$id] = new DocumentResultItem($id, $rank, $item['title'], $exprbuilder->getResultText($item));
    		    }
    		    else
    		    {
    		        $results[$id] = new FolderResultItem($id, $rank, $item['title'], $exprbuilder->getResultText($item));
    		    }
    		}
    	}

    	return $results;

    }

    private function exec_text_query($op, $group)
    {
        if (($this->getContext() != ExprContext::DOCUMENT) || empty($group))
        {
            return array();
        }

    	$exprbuilder = new TextQueryBuilder();

    	if (count($group) == 1)
    	{
    		$query = $exprbuilder->buildComplexQuery($group[0]);
    	}
    	else
    	{
			$query = $exprbuilder->buildSimpleQuery($op, $group);
    	}

    	if (empty($query))
    	{
    	    return array();
    	}

    	$indexer = Indexer::get();
    	global $default;
    	$default->log->debug("SEARCH LUCENE: $query");

    	$results = $indexer->query($query);
    	foreach($results as $item)
    	{
    		$item->Rank = $exprbuilder->getRanking($item);
    		$exprbuilder->setQuery($query);
    		//$item->Text = $exprbuilder->getResultText($item); ?? wipe - done at indexer level
    	}

    	return $results;
    }

	public function evaluate($context = ExprContext::DOCUMENT_AND_FOLDER)
	{
	    if ($context == ExprContext::DOCUMENT_AND_FOLDER)
	    {
	       $docs = $this->evaluate(ExprContext::DOCUMENT);
 	       $folders = $this->evaluate(ExprContext::FOLDER);

	       return array(
	           'docs' => $docs['docs'],
	           'folders' => $folders['folders']);
	    }
	    $this->setContext($context);

		$left = $this->left();
        $right = $this->right();
        $op = $this->op();
        $point = $this->getPoint();
        $result = array();
        if (empty($point))
        {
        	$point = 'point';
        }
		$resultContext = ($this->getContext() == ExprContext::DOCUMENT)?'docs':'folders';

		if ($point == 'merge')
		{
			$leftres = $left->evaluate($context);
			$rightres = $right->evaluate($context);
			switch ($op)
			{
				case ExprOp::OP_AND:
					if ($this->debug) print "\n\nmerge: intersect\n\n";
					$result = OpExpr::intersect($leftres, $rightres);
					break;
				case ExprOp::OP_OR:
					if ($this->debug) print "\n\nmerge: union\n\n";
					$result = OpExpr::union($leftres, $rightres);
					break;
				default:
					throw new Exception("this condition should not happen");
			}
		}
		elseif ($point == 'point')
		{
			if ($this->isDBonly())
			{
				$result[$resultContext] = $this->exec_db_query($op, array($this));
			}
			elseif ($this->isTextOnly())
			{
				$result[$resultContext] = $this->exec_text_query($op, array($this));
			}
			elseif (in_array($op, array(ExprOp::OP_OR, ExprOp::OP_AND)))
			{
			    // do we get to this???
			    // TODO: remove me please.... the simpleQuery stuff should go???
				$db_group = array();
				$text_group = array();
				$this->explore($left, $right, $db_group, 'db');
				$this->explore($left, $right, $text_group, 'text');

				$db_result[$resultContext] = $this->exec_db_query($op, $db_group);
				$text_result[$resultContext] = $this->exec_text_query($op, $text_group);

				switch ($op)
				{
					case ExprOp::OP_AND:
						if ($this->debug) print "\n\npoint: intersect\n\n";
						$result[$resultContext] = OpExpr::intersect($db_result, $text_result);
						break;
					case ExprOp::OP_OR:
						if ($this->debug) print "\n\nmerge: union\n\n";
						$result[$resultContext] = OpExpr::union($db_result, $text_result);
						break;
					default:
						throw new Exception('how did this happen??');
				}
			}
			else
			{
				throw new Exception('and this?');
			}
		}
		else
		{
			// we don't have to do anything
			//throw new Exception('Is this reached ever?');
		}

		$permResults = array();
		foreach($result[$resultContext] as $idx=>$item)
		{
			$permResults[$resultContext][$idx] = $item;
		}

		return $permResults;
	}

    public function toViz(&$str, $phase)
    {
        $expr_id = $this->getExprId();
        $left = $this->left();
        $right = $this->right();
        $hastext = $this->getHasText()?'TEXT':'';
        $hasdb = $this->getHasDb()?'DB':'';
        switch ($phase)
        {
            case 0:
                $not = $this->not()?'NOT':'';
                $str .= "struct$expr_id [style=box, label=\"$expr_id: $not $this->op $this->point $hastext$hasdb\"]\n";
                break;
            case 1:
                $left_id = $left->getExprId();
                $str .= "struct$expr_id -> struct$left_id\n";
                $right_id = $right->getExprId();
                $str .= "struct$expr_id -> struct$right_id\n";
                break;
        }
        $left->toViz($str, $phase);
        $right->toViz($str, $phase);
    }
}

?>