mysql5/mysql-5.7.27/sql/ndb_binlog_extra_row_info.cc

/*
   Copyright (c) 2011, 2014, Oracle and/or its affiliates. All rights reserved.

   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 St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#include "ndb_binlog_extra_row_info.h"
#include <string.h> // memcpy

Ndb_binlog_extra_row_info::
Ndb_binlog_extra_row_info()
{
  flags = 0;
  transactionId = InvalidTransactionId;
  conflictFlags = UnsetConflictFlags;
  /* Prepare buffer with extra row info buffer bytes */
  buff[ EXTRA_ROW_INFO_LEN_OFFSET ] = 0;
  buff[ EXTRA_ROW_INFO_FORMAT_OFFSET ] = ERIF_NDB;
}

void
Ndb_binlog_extra_row_info::
setFlags(Uint16 _flags)
{
  flags = _flags;
}

void
Ndb_binlog_extra_row_info::
setTransactionId(Uint64 _transactionId)
{
  assert(_transactionId != InvalidTransactionId);
  transactionId = _transactionId;
};

void
Ndb_binlog_extra_row_info::
setConflictFlags(Uint16 _conflictFlags)
{
  conflictFlags = _conflictFlags;
}

int
Ndb_binlog_extra_row_info::
loadFromBuffer(const uchar* extra_row_info)
{
  assert(extra_row_info);

  Uint8 length = extra_row_info[ EXTRA_ROW_INFO_LEN_OFFSET ];
  assert(length >= EXTRA_ROW_INFO_HDR_BYTES);
  Uint8 payload_length = length - EXTRA_ROW_INFO_HDR_BYTES;
  Uint8 format = extra_row_info[ EXTRA_ROW_INFO_FORMAT_OFFSET ];

  if (likely(format == ERIF_NDB))
  {
    if (likely(payload_length >= FLAGS_SIZE))
    {
      const uchar* data = &extra_row_info[ EXTRA_ROW_INFO_HDR_BYTES ];
      Uint8 nextPos = 0;

      /* Have flags at least */
      bool error = false;
      Uint16 netFlags;
      memcpy(&netFlags, &data[ nextPos ], FLAGS_SIZE);
      nextPos += FLAGS_SIZE;
      flags = uint2korr((const char*) &netFlags);

      if (flags & NDB_ERIF_TRANSID)
      {
        if (likely((nextPos + TRANSID_SIZE) <= payload_length))
        {
          /*
            Correct length, retrieve transaction id, converting from
            little endian if necessary.
          */
          Uint64 netTransId;
          memcpy(&netTransId,
                 &data[ nextPos ],
                 TRANSID_SIZE);
          nextPos += TRANSID_SIZE;
          transactionId = uint8korr((const char*) &netTransId);
        }
        else
        {
          flags = 0; /* No more processing */
          error = true;
        }
      }
      
      if (flags & NDB_ERIF_CFT_FLAGS)
      {
        if (likely((nextPos + CFT_FLAGS_SIZE) <= payload_length))
        {
          /**
           * Correct length, retrieve conflict flags, converting if 
           * necessary
           */
          Uint16 netCftFlags;
          memcpy(&netCftFlags,
                 &data[ nextPos ],
                 CFT_FLAGS_SIZE);
          nextPos += CFT_FLAGS_SIZE;
          conflictFlags = uint2korr((const char*) & netCftFlags);
        }
        else
        {
          flags = 0; /* No more processing */
          error = true;
        }
      }

      if (likely(!error))
      {
        return 0;
      }
      else
      {
        /* Error - malformed buffer, dump some debugging info */
        fprintf(stderr, 
                "Ndb_binlog_extra_row_info::loadFromBuffer()"
                "malformed buffer - flags : %x nextPos %u "
                "payload_length %u\n",
                uint2korr((const char*) &netFlags),
                nextPos, 
                payload_length);
        return -1;
      }
    }
  }

  /* We currently ignore other formats of extra binlog info, and
   * different lengths.
   */

  return 0;
}

uchar*
Ndb_binlog_extra_row_info::generateBuffer()
{
  /*
    Here we write out the buffer in network format,
    based on the current member settings.
  */
  Uint8 nextPos = EXTRA_ROW_INFO_HDR_BYTES;

  if (flags)
  {
    /* Write current flags into buff */
    Uint16 netFlags = uint2korr((const char*) &flags);
    memcpy(&buff[ nextPos ], &netFlags, FLAGS_SIZE);
    nextPos += FLAGS_SIZE;

    if (flags & NDB_ERIF_TRANSID)
    {
      Uint64 netTransactionId = uint8korr((const char*) &transactionId);
      memcpy(&buff[ nextPos ], &netTransactionId, TRANSID_SIZE);
      nextPos += TRANSID_SIZE;
    }
    
    if (flags & NDB_ERIF_CFT_FLAGS)
    {
      Uint16 netCftFlags = uint2korr((const char*) &conflictFlags);
      memcpy(&buff[ nextPos ], &netCftFlags, CFT_FLAGS_SIZE);
      nextPos += CFT_FLAGS_SIZE;
    }

    assert( nextPos <= MaxLen );
    /* Set length */
    assert( buff[ EXTRA_ROW_INFO_FORMAT_OFFSET ] == ERIF_NDB );
    buff[ EXTRA_ROW_INFO_LEN_OFFSET ] = nextPos;

    return buff;
  }
  return 0;
}