mariadb-columnstore-engine/dbcon/execplan/objectreader.h

/* Copyright (C) 2014 InfiniDB, Inc.

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; version 2 of
   the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
   MA 02110-1301, USA. */

/******************************************************************************
 * $Id: objectreader.h 9633 2013-06-19 13:36:01Z rdempsey $
 *
 *****************************************************************************/

/** @file
 * class ObjectReader interface
 */

#ifndef EXECPLAN_OBJECTREADER_H
#define EXECPLAN_OBJECTREADER_H

#include <exception>
#include <string>
#include <stdint.h>

namespace messageqcpp
{
class ByteStream;
}

namespace execplan
{

class TreeNode;
class ParseTree;
class CalpontExecutionPlan;

/** @brief A class for creating execplan classes from ByteStreams.
 *
 * A class currently used for recreating execplan polymorphic classes
 * and dynamic objects from ByteStreams.
 */

class ObjectReader
{

public:

    class UnserializeException : public std::exception
    {
    public:
        UnserializeException(std::string) throw();
        virtual ~UnserializeException() throw();
        virtual const char* what() const throw();
    private:
        std::string fWhat;
    };

    /** @brief Enumerates classes supporting serialization
     *
     * This defines one constant for each class that supports
     * serialization.
     */
    enum CLASSID
    {
        ZERO,      // an appropriate initializer
        NULL_CLASS,		// to denote that some member is NULL

        /**** TreeNodes */
        TREENODE,
        TREENODEIMPL,
        RETURNEDCOLUMN,
        AGGREGATECOLUMN,
        GROUPCONCATCOLUMN,
        ARITHMETICCOLUMN,
        CONSTANTCOLUMN,
        FUNCTIONCOLUMN,
        ROWCOLUMN,
        WINDOWFUNCTIONCOLUMN,
        PSEUDOCOLUMN,

        SIMPLECOLUMN,
        SIMPLECOLUMN_INT1,
        SIMPLECOLUMN_INT2,
        SIMPLECOLUMN_INT4,
        SIMPLECOLUMN_INT8,
        SIMPLECOLUMN_UINT1,
        SIMPLECOLUMN_UINT2,
        SIMPLECOLUMN_UINT4,
        SIMPLECOLUMN_UINT8,
        SIMPLECOLUMN_DECIMAL1,
        SIMPLECOLUMN_DECIMAL2,
        SIMPLECOLUMN_DECIMAL4,
        SIMPLECOLUMN_DECIMAL8,

        FILTER,
        CONDITIONFILTER,
        EXISTSFILTER,
        SELECTFILTER,
        SIMPLEFILTER,
        SIMPLESCALARFILTER,

        OPERATOR,
        ARITHMETICOPERATOR,
        PREDICATEOPERATOR,
        LOGICOPERATOR,

        /**** /TreeNodes */

        PARSETREE,
        CALPONTSELECTEXECUTIONPLAN,
        CONSTANTFILTER,
        OUTERJOINONFILTER,

        /** UDAF SDK */
        MCSV1_CONTEXT,
        UDAFCOLUMN,
    };

    typedef uint8_t id_t;    //expand as necessary

    /** @brief Creates a new TreeNode object from the ByteStream
     *
     * @param b The ByteStream to create it from
     * @return A newly allocated TreeNode
     */
    static TreeNode* createTreeNode(messageqcpp::ByteStream& b);

    /** @brief Creates a new ParseTree from the ByteStream
     *
     * @param b The ByteStream to create it from
     * @return A newly allocated ParseTree
     */
    static ParseTree* createParseTree(messageqcpp::ByteStream& b);

    /** @brief Creates a new CalpontExecutionPlan from the ByteStream
     *
     * @param b The ByteStream to create it from
     * @return A newly allocated CalpontExecutionPlan
     */
    static CalpontExecutionPlan* createExecutionPlan(messageqcpp::ByteStream& b);

    /** @brief Serialize() for ParseTrees
     *
     * This function effectively serializes a ParseTree.
     * @param tree The ParseTree to write out
     * @param b The ByteStream to write tree to
     */
    static void writeParseTree(const ParseTree* tree,
                               messageqcpp::ByteStream& b);

    /** @brief Verify the type of the next object in the ByteStream
     *
     * @param b The ByteStream to read from
     * @param type The type it should be
     * @throw UnserializeException if the type does not match; this is a fatal error.
     */
    static void checkType(messageqcpp::ByteStream& b, const CLASSID type);
};

}
#endif // EXECPLAN_OBJECTREADER_H