relationships.php

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<?php
function row_to_elggrelationship($row) {
    if ($row instanceof stdClass) {
        return new ElggRelationship($row);
    }

    return false;
}

function get_relationship($id) {
    $row = _elgg_get_relationship_row($id);
    if (!$row) {
        return false;
    }

    return new ElggRelationship($row);
}

function _elgg_get_relationship_row($id) {
    global $CONFIG;

    $id = (int)$id;

    return get_data_row("SELECT * FROM {$CONFIG->dbprefix}entity_relationships WHERE id = $id");
}

function delete_relationship($id) {
    global $CONFIG;

    $id = (int)$id;

    $relationship = get_relationship($id);

    if (elgg_trigger_event('delete', 'relationship', $relationship)) {
        return delete_data("DELETE FROM {$CONFIG->dbprefix}entity_relationships WHERE id = $id");
    }

    return false;
}

function add_entity_relationship($guid_one, $relationship, $guid_two) {
    global $CONFIG;

    if (strlen($relationship) > ElggRelationship::RELATIONSHIP_LIMIT) {
        $msg = "relationship name cannot be longer than " . ElggRelationship::RELATIONSHIP_LIMIT;
        throw InvalidArgumentException($msg);
    }

    $guid_one = (int)$guid_one;
    $relationship = sanitise_string($relationship);
    $guid_two = (int)$guid_two;
    $time = time();

    // Check for duplicates
    if (check_entity_relationship($guid_one, $relationship, $guid_two)) {
        return false;
    }

    $id = insert_data("INSERT INTO {$CONFIG->dbprefix}entity_relationships
        (guid_one, relationship, guid_two, time_created)
        VALUES ($guid_one, '$relationship', $guid_two, $time)");

    if ($id !== false) {
        $obj = get_relationship($id);

        // this event has been deprecated in 1.9. Use 'create', 'relationship'
        $result_old = elgg_trigger_event('create', $relationship, $obj);

        $result = elgg_trigger_event('create', 'relationship', $obj);
        if ($result && $result_old) {
            return true;
        } else {
            delete_relationship($result);
        }
    }

    return false;
}

function check_entity_relationship($guid_one, $relationship, $guid_two) {
    global $CONFIG;

    $guid_one = (int)$guid_one;
    $relationship = sanitise_string($relationship);
    $guid_two = (int)$guid_two;

    $query = "SELECT * FROM {$CONFIG->dbprefix}entity_relationships
        WHERE guid_one=$guid_one
            AND relationship='$relationship'
            AND guid_two=$guid_two limit 1";

    $row = row_to_elggrelationship(get_data_row($query));
    if ($row) {
        return $row;
    }

    return false;
}

function remove_entity_relationship($guid_one, $relationship, $guid_two) {
    global $CONFIG;

    $guid_one = (int)$guid_one;
    $relationship = sanitise_string($relationship);
    $guid_two = (int)$guid_two;

    $obj = check_entity_relationship($guid_one, $relationship, $guid_two);
    if ($obj == false) {
        return false;
    }

    // this event has been deprecated in 1.9. Use 'delete', 'relationship'
    $result_old = elgg_trigger_event('delete', $relationship, $obj);

    $result = elgg_trigger_event('delete', 'relationship', $obj);
    if ($result && $result_old) {
        $query = "DELETE FROM {$CONFIG->dbprefix}entity_relationships
            WHERE guid_one = $guid_one
            AND relationship = '$relationship'
            AND guid_two = $guid_two";

        return (bool)delete_data($query);
    } else {
        return false;
    }
}

function remove_entity_relationships($guid, $relationship = "", $inverse_relationship = false, $type = '') {
    global $CONFIG;

    $guid = (int) $guid;

    if (!empty($relationship)) {
        $relationship = sanitize_string($relationship);
        $where = "AND er.relationship = '$relationship'";
    } else {
        $where = "";
    }

    if (!empty($type)) {
        $type = sanitize_string($type);
        if (!$inverse_relationship) {
            $join = "JOIN {$CONFIG->dbprefix}entities e ON e.guid = er.guid_two";
        } else {
            $join = "JOIN {$CONFIG->dbprefix}entities e ON e.guid = er.guid_one";
            $where .= " AND ";
        }
        $where .= " AND e.type = '$type'";
    } else {
        $join = "";
    }

    $guid_col = $inverse_relationship ? "guid_two" : "guid_one";

    delete_data("
        DELETE er FROM {$CONFIG->dbprefix}entity_relationships AS er
        $join
        WHERE $guid_col = $guid
        $where
    ");

    return true;
}

function get_entity_relationships($guid, $inverse_relationship = false) {
    global $CONFIG;

    $guid = (int)$guid;

    $where = ($inverse_relationship ? "guid_two='$guid'" : "guid_one='$guid'");

    $query = "SELECT * from {$CONFIG->dbprefix}entity_relationships where {$where}";

    return get_data($query, "row_to_elggrelationship");
}

function elgg_get_entities_from_relationship($options) {
    $defaults = array(
        'relationship' => null,
        'relationship_guid' => null,
        'inverse_relationship' => false,
        'relationship_join_on' => 'guid',
    );

    $options = array_merge($defaults, $options);

    $join_column = "e.{$options['relationship_join_on']}";
    $clauses = elgg_get_entity_relationship_where_sql($join_column, $options['relationship'],
        $options['relationship_guid'], $options['inverse_relationship']);

    if ($clauses) {
        // merge wheres to pass to get_entities()
        if (isset($options['wheres']) && !is_array($options['wheres'])) {
            $options['wheres'] = array($options['wheres']);
        } elseif (!isset($options['wheres'])) {
            $options['wheres'] = array();
        }

        $options['wheres'] = array_merge($options['wheres'], $clauses['wheres']);

        // merge joins to pass to get_entities()
        if (isset($options['joins']) && !is_array($options['joins'])) {
            $options['joins'] = array($options['joins']);
        } elseif (!isset($options['joins'])) {
            $options['joins'] = array();
        }

        $options['joins'] = array_merge($options['joins'], $clauses['joins']);

        if (isset($options['selects']) && !is_array($options['selects'])) {
            $options['selects'] = array($options['selects']);
        } elseif (!isset($options['selects'])) {
            $options['selects'] = array();
        }

        $select = array('r.id');

        $options['selects'] = array_merge($options['selects'], $select);

        if (!isset($options['group_by'])) {
            $options['group_by'] = $clauses['group_by'];
        }
    }

    return elgg_get_entities_from_metadata($options);
}

function elgg_get_entity_relationship_where_sql($column, $relationship = null,
$relationship_guid = null, $inverse_relationship = false) {

    if ($relationship == null && $relationship_guid == null) {
        return '';
    }

    global $CONFIG;

    $wheres = array();
    $joins = array();
    $group_by = '';

    if ($inverse_relationship) {
        $joins[] = "JOIN {$CONFIG->dbprefix}entity_relationships r on r.guid_one = $column";
    } else {
        $joins[] = "JOIN {$CONFIG->dbprefix}entity_relationships r on r.guid_two = $column";
    }

    if ($relationship) {
        $wheres[] = "r.relationship = '" . sanitise_string($relationship) . "'";
    }

    if ($relationship_guid) {
        if ($inverse_relationship) {
            $wheres[] = "r.guid_two = '$relationship_guid'";
        } else {
            $wheres[] = "r.guid_one = '$relationship_guid'";
        }
    } else {
        // See #5775. Queries that do not include a relationship_guid must be grouped by entity table alias,
        // otherwise the result set is not unique
        $group_by = $column;
    }

    if ($where_str = implode(' AND ', $wheres)) {

        return array('wheres' => array("($where_str)"), 'joins' => $joins, 'group_by' => $group_by);
    }

    return '';
}

function elgg_list_entities_from_relationship(array $options = array()) {
    return elgg_list_entities($options, 'elgg_get_entities_from_relationship');
}

function elgg_get_entities_from_relationship_count(array $options = array()) {
    $options['selects'][] = "COUNT(e.guid) as total";
    $options['group_by'] = 'r.guid_two';
    $options['order_by'] = 'total desc';
    return elgg_get_entities_from_relationship($options);
}

function elgg_list_entities_from_relationship_count($options) {
    return elgg_list_entities($options, 'elgg_get_entities_from_relationship_count');
}