src/object-db.cc

/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
/*
 * Copyright (c) 2012 University of California, Los Angeles
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Author: Alexander Afanasyev <alexander.afanasyev@ucla.edu>
 *	   Zhenkai Zhu <zhenkai@cs.ucla.edu>
 */

#include "object-db.h"
#include <iostream>
#include <boost/make_shared.hpp>
#include "db-helper.h"
#include <sys/stat.h>

using namespace std;
using namespace Ccnx;
using namespace boost;
namespace fs = boost::filesystem;

const std::string INIT_DATABASE = "\
CREATE TABLE                                                            \n\
    File(                                                               \n\
        device_name     BLOB NOT NULL,                                  \n\
        segment         INTEGER,                                        \n\
        content_object  BLOB,                                           \n\
                                                                        \
        PRIMARY KEY (device_name, segment)                              \n\
    );                                                                  \n\
";

ObjectDb::ObjectDb (const fs::path &folder, const std::string &hash)
{
  fs::path actualFolder = folder / "objects" / hash.substr (0, 2);
  fs::create_directories (actualFolder);
  
  int res = sqlite3_open((actualFolder / hash.substr (2, hash.size () - 2)).c_str (), &m_db);
  if (res != SQLITE_OK)
    {
      BOOST_THROW_EXCEPTION (Error::Db ()
                             << errmsg_info_str ("Cannot open/create dabatabase: [" +
                                                 (actualFolder / hash.substr (2, hash.size () - 2)).string () + "]"));
    }
  
  // Alex: determine if tables initialized. if not, initialize... not sure what is the best way to go...
  // for now, just attempt to create everything

  char *errmsg = 0;
  res = sqlite3_exec (m_db, INIT_DATABASE.c_str (), NULL, NULL, &errmsg);
  if (res != SQLITE_OK && errmsg != 0)
    {
      std::cerr << "DEBUG: " << errmsg << std::endl;
      sqlite3_free (errmsg);
    }  
}

ObjectDb::~ObjectDb ()
{
  int res = sqlite3_close (m_db);
  if (res != SQLITE_OK)
    {
      // complain
    }
}

void
ObjectDb::saveContentObject (const Ccnx::Name &deviceName, sqlite3_int64 segment, const Ccnx::Bytes &data)
{
  sqlite3_stmt *stmt;
  sqlite3_prepare_v2 (m_db, "INSERT INTO File "
                      "(device_name, segment, content_object) "
                      "VALUES (?, ?, ?)", -1, &stmt, 0);

  CcnxCharbufPtr buf = deviceName.toCcnxCharbuf ();
  sqlite3_bind_blob (stmt, 1, buf->buf (), buf->length (), SQLITE_TRANSIENT);
  sqlite3_bind_int64 (stmt, 2, segment);
  sqlite3_bind_blob (stmt, 3, &data[0], data.size (), SQLITE_TRANSIENT);

  sqlite3_step (stmt);
  sqlite3_finalize (stmt);
}

Ccnx::BytesPtr
ObjectDb::fetchSegment (const Ccnx::Name &deviceName, sqlite3_int64 segment)
{
  sqlite3_stmt *stmt;
  sqlite3_prepare_v2 (m_db, "SELECT content_object FROM File WHERE device_name=? AND segment=?", -1, &stmt, 0);

  CcnxCharbufPtr buf = deviceName.toCcnxCharbuf ();
  sqlite3_bind_blob (stmt, 1, buf->buf (), buf->length (), SQLITE_TRANSIENT);
  sqlite3_bind_int64 (stmt, 2, segment);

  BytesPtr ret;
  
  int res = sqlite3_step (stmt);
  if (res == SQLITE_ROW)
    {
      const unsigned char *buf = reinterpret_cast<const unsigned char*> (sqlite3_column_blob (stmt, 0));
      int bufBytes = sqlite3_column_bytes (stmt, 0);

      ret = make_shared<Bytes> (buf, buf+bufBytes);
    }

  sqlite3_finalize (stmt);

  return ret;
}

// sqlite3_int64
// ObjectDb::getNumberOfSegments (const Ccnx::Name &deviceName)
// {
// }