src/object-db.cpp

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/**
 * Copyright (c) 2013-2017, Regents of the University of California.
 *
 * This file is part of ChronoShare, a decentralized file sharing application over NDN.
 *
 * ChronoShare 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, either
 * version 3 of the License, or (at your option) any later version.
 *
 * ChronoShare 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 copies of the GNU General Public License along with
 * ChronoShare, e.g., in COPYING.md file.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ChronoShare authors and contributors.
 */

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

_LOG_INIT(Object.Db);

using namespace std;
using namespace Ndnx;
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\
CREATE INDEX device ON File(device_name);                               \n\
";

ObjectDb::ObjectDb(const fs::path& folder, const std::string& hash)
  : m_lastUsed(time(NULL))
{
  fs::path actualFolder = folder / "objects" / hash.substr(0, 2);
  fs::create_directories(actualFolder);

  _LOG_DEBUG("Open " << (actualFolder / hash.substr(2, hash.size() - 2)));

  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) {
    // _LOG_TRACE ("Init \"error\": " << errmsg);
    sqlite3_free(errmsg);
  }

  // _LOG_DEBUG ("open db");

  willStartSave();
}

bool
ObjectDb::DoesExist(const boost::filesystem::path& folder, const Ccnx::Name& deviceName,
                    const std::string& hash)
{
  fs::path actualFolder = folder / "objects" / hash.substr(0, 2);
  bool retval = false;

  sqlite3* db;
  int res = sqlite3_open((actualFolder / hash.substr(2, hash.size() - 2)).c_str(), &db);
  if (res == SQLITE_OK) {
    sqlite3_stmt* stmt;
    sqlite3_prepare_v2(db,
                       "SELECT count(*), count(nullif(content_object,0)) FROM File WHERE device_name=?",
                       -1, &stmt, 0);

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

    int res = sqlite3_step(stmt);
    if (res == SQLITE_ROW) {
      int countAll = sqlite3_column_int(stmt, 0);
      int countNonNull = sqlite3_column_int(stmt, 1);

      _LOG_TRACE("Total segments: " << countAll << ", non-empty segments: " << countNonNull);

      if (countAll > 0 && countAll == countNonNull) {
        retval = true;
      }
    }

    sqlite3_finalize(stmt);
  }

  sqlite3_close(db);
  return retval;
}


ObjectDb::~ObjectDb()
{
  didStopSave();

  // _LOG_DEBUG ("close db");
  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);

  //_LOG_DEBUG ("Saving content object for [" << deviceName << ", seqno: " << segment << ", size: " << data.size () << "]");

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

  sqlite3_step(stmt);
  //_LOG_DEBUG ("After saving object: " << sqlite3_errmsg (m_db));
  sqlite3_finalize(stmt);

  // update last used time
  m_lastUsed = time(NULL);
}

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);

  // update last used time
  m_lastUsed = time(NULL);

  return ret;
}

time_t
ObjectDb::secondsSinceLastUse()
{
  return (time(NULL) - m_lastUsed);
}

// sqlite3_int64
// ObjectDb::getNumberOfSegments (const Ndnx::Name &deviceName)
// {
//   sqlite3_stmt *stmt;
//   sqlite3_prepare_v2 (m_db, "SELECT count(*) FROM File WHERE device_name=?", -1, &stmt, 0);

//   bool retval = false;
//   int res = sqlite3_step (stmt);
//   if (res == SQLITE_ROW)
//     {
//       retval = true;
//     }
//   sqlite3_finalize (stmt);

//   return retval;
// }

void
ObjectDb::willStartSave()
{
  sqlite3_exec(m_db, "BEGIN TRANSACTION;", 0, 0, 0);
  // _LOG_DEBUG ("Open transaction: " << sqlite3_errmsg (m_db));
}

void
ObjectDb::didStopSave()
{
  sqlite3_exec(m_db, "END TRANSACTION;", 0, 0, 0);
  // _LOG_DEBUG ("Close transaction: " << sqlite3_errmsg (m_db));
}