ilearngraphrelation.php

См. документацию.

<?php

interface ILearnGraphRelation
{
    public static function Link ($parentNodeId, $childNodeId, $arProperties);

    public static function Unlink ($parentNodeId, $childNodeId);

    public static function SetProperty ($parentNodeId, $childNodeId, $propertyName, $value);

    public static function GetProperty ($parentNodeId, $childNodeId, $propertyName);

    public static function ListImmediateNeighbours ($nodeId);

    public static function ListImmediateParents ($nodeId);

    public static function ListImmediateChilds ($nodeId);
}

final class CLearnGraphRelation implements ILearnGraphRelation
{
    // For bitmask:
    const NBRS_IMDT_PARENTS = 0x1;     // immediate parent neighbours
    const NBRS_IMDT_CHILDS  = 0x2;      // immediate child neighbours
 
    private static $arNodesCache = array();
    private static $nodesCached = 0;
 
 
    public static function ListImmediateParents ($nodeId)
    {
        return (self::_ListImmediateNeighbours ($nodeId, self::NBRS_IMDT_PARENTS));
    }
 
    public static function ListImmediateChilds ($nodeId)
    {
        return (self::_ListImmediateNeighbours ($nodeId, self::NBRS_IMDT_CHILDS));
    }
 
    public static function ListImmediateNeighbours ($nodeId)
    {
        return (self::_ListImmediateNeighbours ($nodeId, self::NBRS_IMDT_PARENTS | self::NBRS_IMDT_CHILDS));
    }
 
    protected static function _ListImmediateNeighbours ($nodeId, $bitmaskSearchMode)
    {
        global $DB;
 
        $arWhere = array();
 
        // List parents?
        if ($bitmaskSearchMode & self::NBRS_IMDT_PARENTS)
            $arWhere[] = "TARGET_NODE='" . (int) ($nodeId + 0) . "'";
 
        // List childs?
        if ($bitmaskSearchMode & self::NBRS_IMDT_CHILDS)
            $arWhere[] = "SOURCE_NODE='" . (int) ($nodeId + 0) . "'";
 
        // Prepare string for query
        $sqlWhere = implode (' OR ', $arWhere);
 
        if ($sqlWhere == '')
        {
            throw new LearnException ('EA_PARAMS: nothing to search (check search mode bitmask);',
                LearnException::EXC_ERR_GR_GET_NEIGHBOURS | LearnException::EXC_ERR_ALL_LOGIC);
        }
 
        if ( ! array_key_exists($sqlWhere, self::$arNodesCache) )
        {
            // Get graph edge
            $rc = $DB->Query (
                "SELECT SOURCE_NODE, TARGET_NODE, SORT
                FROM b_learn_lesson_edges
                WHERE " . $sqlWhere,
                $ignore_errors = true);
 
            if ($rc === false)
                throw new LearnException ('EA_SQLERROR', LearnException::EXC_ERR_GR_GET_NEIGHBOURS);
 
            $result = array();
 
            // Postprocessing of result
            while ($arData = $rc->Fetch())
            {
                $result[] = array (
                    'SOURCE_NODE'   => $arData['SOURCE_NODE'],
                    'TARGET_NODE'   => $arData['TARGET_NODE'],
                    'PARENT_LESSON' => $arData['SOURCE_NODE'],
                    'CHILD_LESSON'  => $arData['TARGET_NODE'],
                    'SORT'          => (int) $arData['SORT']
                );
            }
 
            // limit static cache size to 1024 nodes
            if (self::$nodesCached < 1024)
            {
                ++self::$nodesCached;
                self::$arNodesCache[$sqlWhere] = $result;
            }
        }
        else
            $result = self::$arNodesCache[$sqlWhere];
 
 
        return ($result);
    }
 
    public static function Link ($parentNodeId, $childNodeId, $arProperties)
    {
        global $DB;
 
        // reset static cache
        self::$arNodesCache = array();
        self::$nodesCached = 0;
 
        $args_check = is_array($arProperties)  // must be an array
            && (count($arProperties) === 1)
            && ($parentNodeId > 0)
            && ($childNodeId > 0);
 
        // Only SORT allowed
        $args_check = $args_check && isset ($arProperties['SORT']);
 
        // check SORT admitted range: number
        if (isset($arProperties['SORT']))
            $args_check = $args_check && is_numeric ($arProperties['SORT']) && is_int ($arProperties['SORT'] + 0);
        else
            $args_check = false;
 
        if ( ! $args_check )
        {
            throw new LearnException (
                'EA_PARAMS: ' . $parentNodeId . ' / ' . $childNodeId . ' / ' . var_export($arProperties, true), 
                LearnException::EXC_ERR_GR_LINK);
        }
 
        // normalize & sanitize
        {
            $sort = (int) ($arProperties['SORT'] + 0);
 
            $parentNodeId += 0;
            $childNodeId  += 0;
        }
 
        // Create graph edge
        $rc = $DB->Query (
            "INSERT INTO b_learn_lesson_edges (SOURCE_NODE, TARGET_NODE, SORT)
            VALUES ('" . $parentNodeId . "', '" . $childNodeId . "', '" . $sort . "')",
            $ignore_errors = true);
 
        if ($rc === false)
            throw new LearnException ('EA_SQLERROR', LearnException::EXC_ERR_GR_LINK);
    }
 
    public static function Unlink ($parentNodeId, $childNodeId)
    {
        global $DB;
 
        // reset static cache
        self::$arNodesCache = array();
        self::$nodesCached = 0;
 
        $args_check = ($parentNodeId > 0) && ($childNodeId > 0);
 
        if ( ! $args_check )
            throw new LearnException ('EA_PARAMS', LearnException::EXC_ERR_GR_UNLINK);
 
        $parentNodeId += 0;
        $childNodeId  += 0;
 
        // Remove graph edge
        $rc = $DB->Query (
            "DELETE FROM b_learn_lesson_edges
            WHERE SOURCE_NODE = '" . $parentNodeId . "'
                AND TARGET_NODE = '" . $childNodeId . "'",
            $ignore_errors = true);
 
        if ($rc === false)
            throw new LearnException ('EA_SQLERROR', LearnException::EXC_ERR_GR_UNLINK);
 
        if ($rc->AffectedRowsCount() == 0)
            throw new LearnException ('EA_NOT_EXISTS', LearnException::EXC_ERR_GR_UNLINK);
    }
 
    public static function SetProperty ($parentNodeId, $childNodeId, $propertyName, $value)
    {
        global $DB;
 
        // reset static cache
        self::$arNodesCache = array();
        self::$nodesCached = 0;
 
        $args_check = ($parentNodeId > 0) && ($childNodeId > 0)
            && ( in_array ($propertyName, array('SORT'), true) );
 
        if ($propertyName === 'SORT')
        {
            // check SORT admitted range: number
            $args_check = $args_check && is_numeric ($value) && is_int ($value + 0);
        }
 
        if ( ! $args_check )
            throw new LearnException ('EA_PARAMS', LearnException::EXC_ERR_GR_SET_PROPERTY);
 
        $parentNodeId += 0;
        $childNodeId  += 0;
 
        switch ($propertyName)
        {
            case 'SORT':
                $value = (int) ($value + 0);
 
                $arFields = array ('SORT' => "'" . $value . "'");
            break;
 
            default:
                throw new LearnException ('EA_PARAMS: unknown property name: '
                    . $propertyName, LearnException::EXC_ERR_GR_SET_PROPERTY);
            break;
        }
 
        // Update graph edge
        $rc = $DB->Update ('b_learn_lesson_edges', $arFields,
            "WHERE SOURCE_NODE='" . $parentNodeId . "'
                AND TARGET_NODE='" . $childNodeId . "'", __LINE__, false,
                false); // we must halt on errors due to bug in CDatabase::Update();

        if ($rc === false)
            throw new LearnException ('EA_SQLERROR', LearnException::EXC_ERR_GR_SET_PROPERTY);
 
        /*
        This is not correctly, because there is can be update to value, which already set in db. And not affected rows will be.
        Consistent check of existence of relation needs transaction with one more sql-prerequest,
        so don't check it because of perfomance penalties and DB::transactions problems. :(
                if ($rc->AffectedRowsCount() == 0)
                    throw new LearnException ('EA_NOT_EXISTS', LearnException::EXC_ERR_GR_SET_PROPERTY);
        */
    }
 
    public static function GetProperty ($parentNodeId, $childNodeId, $propertyName)
    {
        global $DB;
 
        $args_check = ($parentNodeId > 0) && ($childNodeId > 0)
            && ( in_array ($propertyName, array('SORT'), true) );
 
        if ( ! $args_check )
            throw new LearnException ('EA_PARAMS', LearnException::EXC_ERR_GR_GET_PROPERTY);
 
        $parentNodeId += 0;
        $childNodeId  += 0;
 
        // Prepare DB field name
        switch ($propertyName)
        {
            case 'SORT':
                $field = 'SORT';
            break;
 
            default:
                throw new LearnException ('EA_PARAMS: unknown property name: '
                    . $propertyName, LearnException::EXC_ERR_GR_GET_PROPERTY);
            break;
        }
 
        // Get graph edge
        $rc = $DB->Query (
            "SELECT " . $field . "
            FROM b_learn_lesson_edges
            WHERE SOURCE_NODE='" . $parentNodeId . "'
                AND TARGET_NODE='" . $childNodeId . "'",
            $ignore_errors = true);
 
        if ($rc === false)
            throw new LearnException ('EA_SQLERROR', LearnException::EXC_ERR_GR_GET_PROPERTY);
 
        if ( ! (($arData = $rc->Fetch()) && isset($arData[$field])) )
            throw new LearnException ('EA_NOT_EXISTS', LearnException::EXC_ERR_GR_GET_PROPERTY);
 
        // Postprocessing of result
        switch ($propertyName)
        {
            case 'SORT':
                $rc = (int) $arData[$field];
            break;
 
            default:
                throw new LearnException ('EA_PARAMS: unknown property name: '
                    . $propertyName, LearnException::EXC_ERR_GR_GET_PROPERTY);
            break;
        }
 
        return ($rc);
    }
}