x/src/command_delegate.h

/*
 * Copyright (c) 2015, 2021, Oracle and/or its affiliates.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License, version 2.0,
 * as published by the Free Software Foundation.
 *
 * This program is also distributed with certain software (including
 * but not limited to OpenSSL) that is licensed under separate terms,
 * as designated in a particular file or component or in included license
 * documentation.  The authors of MySQL hereby grant you an additional
 * permission to link the program and your derivative works with the
 * separately licensed software that they have included with MySQL.
 *
 * 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, version 2.0, 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 St, Fifth Floor, Boston, MA
 * 02110-1301  USA
 */

#ifndef _XPL_COMMAND_DELEGATE_H_
#define _XPL_COMMAND_DELEGATE_H_

#include "ngs/protocol_encoder.h"

#include "m_ctype.h"
#include "decimal.h"
#include "mysql/service_command.h"

namespace xpl
{
  class Command_delegate
  {
  public:
    struct Field_type
    {
      enum_field_types type;
      unsigned int flags;
    };
    typedef std::vector<Field_type> Field_types;

    Command_delegate()
    {
      reset();
    }
    virtual ~Command_delegate() {}

    ngs::Error_code get_error() const
    {
      if (m_sql_errno == 0)
        return ngs::Error_code();
      else
        return ngs::Error_code(m_sql_errno, m_err_msg, m_sqlstate);
    }

    inline uint server_status() const { return m_server_status; }
    inline uint statement_warn_count() const { return m_statement_warn_count; }
    inline ulonglong affected_rows() const { return m_affected_rows; }
    inline ulonglong last_insert_id() const { return m_last_insert_id; }
    inline const std::string &message() const { return m_message; }
    inline const Field_types &get_field_types() const { return m_field_types; }

    bool killed() const { return m_killed; }
    bool got_eof() const { return m_got_eof; }

    virtual void reset()
    {
      m_server_status = 0;
      m_statement_warn_count = 0;
      m_affected_rows = 0;
      m_last_insert_id = 0;
      m_sql_errno = 0;
      m_killed = false;
      m_streaming_metadata = false;
      m_field_types.clear();
      m_got_eof = false;
      m_message = "";
    }

    const st_command_service_cbs *callbacks() const
    {
      static st_command_service_cbs cbs = {
        &Command_delegate::call_start_result_metadata,
        &Command_delegate::call_field_metadata,
        &Command_delegate::call_end_result_metadata,
        &Command_delegate::call_start_row,
        &Command_delegate::call_end_row,
        &Command_delegate::call_abort_row,
        &Command_delegate::call_get_client_capabilities,
        &Command_delegate::call_get_null,
        &Command_delegate::call_get_integer,
        &Command_delegate::call_get_longlong,
        &Command_delegate::call_get_decimal,
        &Command_delegate::call_get_double,
        &Command_delegate::call_get_date,
        &Command_delegate::call_get_time,
        &Command_delegate::call_get_datetime,
        &Command_delegate::call_get_string,
        &Command_delegate::call_handle_ok,
        &Command_delegate::call_handle_error,
        &Command_delegate::call_shutdown
      };
      return &cbs;
    }

    virtual enum cs_text_or_binary representation() const = 0;

  protected:
    uint m_server_status;
    uint m_statement_warn_count;
    ulonglong m_affected_rows;
    ulonglong m_last_insert_id;
    std::string m_message;
    Field_types m_field_types;

    uint m_sql_errno;
    std::string m_err_msg;
    std::string m_sqlstate;

    st_command_service_cbs m_callbacks;

    bool m_killed;
    bool m_streaming_metadata;
    bool m_got_eof;

  public:
    /*** Getting metadata ***/
    /*
      Indicates beginning of metadata for the result set

      @param num_cols Number of fields being sent
      @param flags    Flags to alter the metadata sending
      @param resultcs Charset of the result set

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int start_result_metadata(uint num_cols, uint flags,
                                          const CHARSET_INFO *resultcs)
    {
      m_field_types.clear();
      return false;
    }

    /*
      Field metadata is provided via this callback

      @param field   Field's metadata (see field.h)
      @param charset Field's charset

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int field_metadata(struct st_send_field *field,
                                   const CHARSET_INFO *charset)
    {
      Field_type type = { field->type, field->flags };
      m_field_types.push_back(type);

      return false;
    }

    /*
      Indicates end of metadata for the result set

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int end_result_metadata(uint server_status,
                                        uint warn_count)
    {
      return false;
    }

    /*
      Indicates the beginning of a new row in the result set/metadata

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int start_row()
    {
      return false;
    }

    /*
     Indicates the end of the current row in the result set/metadata

     @returns
     true  an error occured, server will abort the command
     false ok
    */
    virtual int end_row()
    {
      return false;
    }

    /*
      An error occured during execution

      @details This callback indicates that an error occureded during command
      execution and the partial row should be dropped. Server will raise error
      and return.

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual void abort_row()
    {
    }

    /*
      Return client's capabilities (see mysql_com.h, CLIENT_*)

      @return Bitmap of client's capabilities
    */
    virtual ulong get_client_capabilities()
    {
      return 0;
    }

    /****** Getting data ******/
    /*
      Receive NULL value from server

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_null()
    {
      return false;
    }

    /*
      Get TINY/SHORT/LONG value from server

      @param value         Value received

      @note In order to know which type exactly was received, the plugin must
      track the metadata that was sent just prior to the result set.

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_integer(longlong value)
    {
      return false;
    }

    /*
      Get LONGLONG value from server

      @param value         Value received
      @param unsigned_flag TRUE <=> value is unsigned

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_longlong(longlong value, uint unsigned_flag)
    {
      return false;
    }

    /*
      Receive DECIMAL value from server

      @param value Value received

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_decimal(const decimal_t * value)
    {
      return false;
    }

    /*
      Get FLOAT/DOUBLE from server

      @param value    Value received
      @param decimals Number of decimals

      @note In order to know which type exactly was received, the plugin must
      track the metadata that was sent just prior to the result set.

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_double(double value, uint32 decimals)
    {
      return false;
    }

    /*
      Get DATE value from server

      @param value    Value received

      @returns
      true  an error occured during storing, server will abort the command
      false ok
    */
    virtual int get_date(const MYSQL_TIME * value)
    {
      return false;
    }

    /*
      Get TIME value from server

      @param value    Value received
      @param decimals Number of decimals

      @returns
      true  an error occured during storing, server will abort the command
      false ok
    */
    virtual int get_time(const MYSQL_TIME * value, uint decimals)
    {
      return false;
    }

    /*
      Get DATETIME value from server

      @param value    Value received
      @param decimals Number of decimals

      @returns
      true  an error occured during storing, server will abort the command
      false ok
    */
    virtual int get_datetime(const MYSQL_TIME * value, uint decimals)
    {
      return false;
    }

    /*
      Get STRING value from server

      @param value   Value received
      @param length  Value's length
      @param valuecs Value's charset

      @returns
      true  an error occured, server will abort the command
      false ok
    */
    virtual int get_string(const char * const value, size_t length,
                           const CHARSET_INFO * const valuecs)
    {
      return false;
    }

    /****** Getting execution status ******/
    /*
      Command ended with success

      @param server_status        Status of server (see mysql_com.h,
      SERVER_STATUS_*)
      @param statement_warn_count Number of warnings thrown during execution
      @param affected_rows        Number of rows affected by the command
      @param last_insert_id       Last insert id being assigned during execution
      @param message              A message from server
    */
    virtual void handle_ok(uint server_status, uint statement_warn_count,
                           ulonglong affected_rows, ulonglong last_insert_id,
                           const char * const message)
    {
      m_server_status = server_status;
      m_statement_warn_count = statement_warn_count;
      m_affected_rows = affected_rows;
      m_last_insert_id = last_insert_id;
      m_message = message ? message : "";
    }

    /*
     Command ended with ERROR

     @param sql_errno Error code
     @param err_msg   Error message
     @param sqlstate  SQL state correspongin to the error code
    */
    virtual void handle_error(uint sql_errno, const char * const err_msg,
                              const char * const sqlstate)
    {
      m_sql_errno = sql_errno;
      m_err_msg = err_msg ? err_msg : "";
      m_sqlstate = sqlstate ? sqlstate : "";
    }

    /*
     Session was shutdown while command was running

    */
    virtual void shutdown(int flag)
    {
      m_killed = true;
    }

  private:
    Command_delegate(const Command_delegate &);
    Command_delegate &operator=(const Command_delegate &);

    static int call_start_result_metadata(void *ctx, uint num_cols, uint flags,
                                          const CHARSET_INFO *resultcs)
    {
      Command_delegate *self = static_cast<Command_delegate*>(ctx);
      self->m_streaming_metadata = true;
      return self->start_result_metadata(num_cols, flags, resultcs);
    }

    static int call_field_metadata(void *ctx, struct st_send_field *field,
                                  const CHARSET_INFO *charset)
    {
      return static_cast<Command_delegate*>(ctx)->field_metadata(field, charset);
    }

    static int call_end_result_metadata(void *ctx, uint server_status,
                                        uint warn_count)
    {
      Command_delegate *self = static_cast<Command_delegate*>(ctx);
      int tmp = self->end_result_metadata(server_status, warn_count);
      self->m_streaming_metadata = false;
      return tmp;
    }

    static int call_start_row(void *ctx)
    {
      Command_delegate *self = static_cast<Command_delegate*>(ctx);
      if (self->m_streaming_metadata)
        return false;
      return self->start_row();
    }

    static int call_end_row(void *ctx)
    {
      Command_delegate *self = static_cast<Command_delegate*>(ctx);
      if (self->m_streaming_metadata)
        return false;
      return self->end_row();
    }

    static void call_abort_row(void *ctx)
    {
      static_cast<Command_delegate*>(ctx)->abort_row();
    }

    static ulong call_get_client_capabilities(void *ctx)
    {
      return static_cast<Command_delegate*>(ctx)->get_client_capabilities();
    }

    static int call_get_null(void * ctx)
    {
      return static_cast<Command_delegate*>(ctx)->get_null();
    }

    static int call_get_integer(void * ctx, longlong value)
    {
      return static_cast<Command_delegate*>(ctx)->get_integer(value);
    }

    static int call_get_longlong(void * ctx, longlong value, uint unsigned_flag)
    {
      return static_cast<Command_delegate*>(ctx)->get_longlong(value, unsigned_flag);
    }

    static int call_get_decimal(void * ctx, const decimal_t * value)
    {
      return static_cast<Command_delegate*>(ctx)->get_decimal(value);
    }

    static int call_get_double(void * ctx, double value, uint32 decimals)
    {
      return static_cast<Command_delegate*>(ctx)->get_double(value, decimals);
    }

    static int call_get_date(void * ctx, const MYSQL_TIME * value)
    {
      return static_cast<Command_delegate*>(ctx)->get_date(value);
    }

    static int call_get_time(void * ctx, const MYSQL_TIME * value, uint decimals)
    {
      return static_cast<Command_delegate*>(ctx)->get_time(value, decimals);
    }

    static int call_get_datetime(void * ctx, const MYSQL_TIME * value, uint decimals)
    {
      return static_cast<Command_delegate*>(ctx)->get_datetime(value, decimals);
    }

    static int call_get_string(void * ctx,
                               const char * const value, size_t length,
                               const CHARSET_INFO * const valuecs)
    {
      return static_cast<Command_delegate*>(ctx)->get_string(value, length, valuecs);
    }

    static void call_handle_ok(void * ctx,
                               uint server_status, uint statement_warn_count,
                               ulonglong affected_rows, ulonglong last_insert_id,
                               const char * const message)
    {
      static_cast<Command_delegate*>(ctx)->m_got_eof = (message == NULL);

      static_cast<Command_delegate*>(ctx)->handle_ok(server_status, statement_warn_count,
                                                     affected_rows, last_insert_id,
                                                     message);
    }

    static void call_handle_error(void * ctx, uint sql_errno, const char * const err_msg,
                                  const char * const sqlstate)
    {
      static_cast<Command_delegate*>(ctx)->handle_error(sql_errno, err_msg, sqlstate);
    }

    static void call_shutdown(void *ctx, int flag)
    {
      static_cast<Command_delegate*>(ctx)->shutdown(flag);
    }
  };
} // namespace xpl

#endif // _XPL_COMMAND_DELEGATE_H_