/* 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: mastersegmenttable.cpp 1904 2013-06-14 18:30:46Z dhall $
 *
 ****************************************************************************/

#include <cstdio>
#include <cstdlib>
#include <stdexcept>
#include <sys/types.h>
#include <cerrno>
using namespace std;

#include <boost/thread.hpp>
#include <boost/interprocess/shared_memory_object.hpp>
#include <boost/interprocess/mapped_region.hpp>
#include <boost/version.hpp>
namespace bi = boost::interprocess;

#include "brmtypes.h"
#include "calpontsystemcatalog.h"
#include "rwlock.h"
using namespace rwlock;
#define MASTERSEGMENTTABLE_DLLEXPORT
#include "mastersegmenttable.h"
#undef MASTERSEGMENTTABLE_DLLEXPORT

#include "installdir.h"

namespace
{
using namespace BRM;

}

namespace BRM
{
/*static*/
boost::mutex MasterSegmentTableImpl::fInstanceMutex;

/*static*/
MasterSegmentTableImpl* MasterSegmentTableImpl::fInstance = 0;

/*static*/
MasterSegmentTableImpl* MasterSegmentTableImpl::makeMasterSegmentTableImpl(int key, int size)
{
  boost::mutex::scoped_lock lk(fInstanceMutex);

  if (fInstance)
    return fInstance;

  fInstance = new MasterSegmentTableImpl(key, size);

  return fInstance;
}

MasterSegmentTableImpl::MasterSegmentTableImpl(int key, int size)
{
  string keyName = ShmKeys::keyToName(key);

  try
  {
    bi::permissions perms;
    perms.set_unrestricted();
    bi::shared_memory_object shm(bi::create_only, keyName.c_str(), bi::read_write, perms);
    shm.truncate(size);
    fShmobj.swap(shm);
  }
  catch (bi::interprocess_exception& biex)
  {
    if (biex.get_error_code() == bi::already_exists_error)
    {
      try
      {
        bi::shared_memory_object shm(bi::open_only, keyName.c_str(), bi::read_write);
        fShmobj.swap(shm);
      }
      catch (exception& e)
      {
        ostringstream o;
        o << "BRM caught an exception attaching to a shared memory segment (" << keyName << "): " << e.what();
        log(o.str());
        throw;
      }
    }
    else
    {
      ostringstream o;
      o << "BRM caught an exception creating a shared memory segment (" << keyName << "): " << biex.what();
      log(o.str());
      throw;
    }
  }
  bi::mapped_region region(fShmobj, bi::read_write);
  fMapreg.swap(region);
}

MSTEntry::MSTEntry() : tableShmkey(-1), allocdSize(0), currentSize(0)
{
}

MasterSegmentTable::MasterSegmentTable()
{

  int i;
  bool initializer = false;

  RWLockKeys[0] = fShmKeys.KEYRANGE_EXTENTMAP_BASE;
  RWLockKeys[1] = fShmKeys.KEYRANGE_EMFREELIST_BASE;
  RWLockKeys[2] = fShmKeys.KEYRANGE_VBBM_BASE;
  RWLockKeys[3] = fShmKeys.KEYRANGE_VSS_BASE;
  RWLockKeys[4] = fShmKeys.KEYRANGE_CL_BASE;
  RWLockKeys[5] = fShmKeys.KEYRANGE_EXTENTMAP_INDEX_BASE;

  try
  {
    // if initializer is returned false, then this is not the first time for this key.
    rwlock[0].reset(new RWLock(RWLockKeys[0], &initializer));
  }
  catch (exception& e)
  {
    cerr << "ControllerSegmentTable: RWLock() threw: " << e.what() << endl;
    throw;
  }

  if (rwlock[0] == NULL)
  {
    cerr << "ControllerSegmentTable(): RWLock() failed..?" << endl;
    throw runtime_error("ControllerSegmentTable(): RWLock() failed..?");
  }

  for (i = 1; i < nTables; i++)
    rwlock[i].reset(new RWLock(RWLockKeys[i]));

  makeMSTSegment();

  if (initializer)
  {
    initMSTData();
    rwlock[0]->write_unlock();
  }
  else
  {
    rwlock[0]->read_lock_priority();  // this is to synch with the initializer
    rwlock[0]->read_unlock();
  }
}

MasterSegmentTable::~MasterSegmentTable()
{
  //	int i;

  //	for (i = 0; i < nTables; i++)
  //		delete rwlock[i];
}

void MasterSegmentTable::makeMSTSegment()
{
  fPImpl = MasterSegmentTableImpl::makeMasterSegmentTableImpl(fShmKeys.MST_SYSVKEY, MSTshmsize);
  fShmDescriptors = static_cast<MSTEntry*>(fPImpl->fMapreg.get_address());
}

void MasterSegmentTable::initMSTData()
{
  void* dp = static_cast<void*>(&fShmDescriptors);
  memset(dp, 0, MSTshmsize);
}

MSTEntry* MasterSegmentTable::getTable_read(int num, bool block) const
{
  if (num < 0 || num > nTables - 1)
    throw std::invalid_argument("ControllerSegmentTable::getTable_read()");

  if (!block)
    try
    {
      rwlock[num]->read_lock(false);
    }
    catch (rwlock::wouldblock& e)
    {
      return NULL;
    }
  else
    rwlock[num]->read_lock();

  return &fShmDescriptors[num];
}

MSTEntry* MasterSegmentTable::getTable_write(int num, bool block) const
{
  if (num < 0 || num > nTables - 1)
    throw std::invalid_argument("ControllerSegmentTable::getTable_write()");

  if (!block)
    try
    {
      rwlock[num]->write_lock(false);
    }
    catch (rwlock::wouldblock& e)
    {
      return NULL;
    }
  else
    rwlock[num]->write_lock();

  return &fShmDescriptors[num];
}

void MasterSegmentTable::getTable_upgrade(int num) const
{
  if (num < 0 || num > nTables - 1)
    throw std::invalid_argument("ControllerSegmentTable::getTable_upgrade()");

  rwlock[num]->upgrade_to_write();
}

void MasterSegmentTable::getTable_downgrade(int num) const
{
  if (num < 0 || num > nTables - 1)
    throw std::invalid_argument("ControllerSegmentTable::getTable_downgrade()");

  rwlock[num]->downgrade_to_read();
}

void MasterSegmentTable::releaseTable_read(int num) const
{
  if (num < 0 || num >= nTables)
    throw std::invalid_argument("ControllerSegmentTable::releaseTable()");

  rwlock[num]->read_unlock();
}

void MasterSegmentTable::releaseTable_write(int num) const
{
  if (num < 0 || num >= nTables)
    throw std::invalid_argument("ControllerSegmentTable::releaseTable()");

  rwlock[num]->write_unlock();
}

}  // namespace BRM