Method open

source/core/StarBTreeDatabase.cpp:103–167

}

bool BTreeDatabase::open() {
  WriteLocker writeLocker(m_lock);
  if (m_open)
    return false;

  if (!m_device)
    throw DBException("BlockStorage::open called with no IODevice set");

  if (!m_device->isOpen())
    m_device->open(IOMode::ReadWrite);

  m_open = true;

  if (m_device->size() > 0) {
    DataStreamIODevice ds(m_device);
    ds.seek(0);

    auto magic = ds.readBytes(VersionMagicSize);
    if (magic != ByteArray::fromCString(VersionMagic))
      throw DBException("Device is not a valid BTreeDatabase file");

    m_blockSize = ds.read<uint32_t>();

    auto contentIdentifier = ds.readBytes(ContentIdentifierStringSize);
    contentIdentifier.appendByte('\0');
    m_contentIdentifier = String(contentIdentifier.ptr());
    m_keySize = ds.read<uint32_t>();

    readRoot();

    if (m_device->isWritable())
      m_device->resize(m_deviceSize);

    return false;

  } else {
    m_deviceSize = HeaderSize;
    m_device->resize(m_deviceSize);
    m_headFreeIndexBlock = InvalidBlockIndex;

    DataStreamIODevice ds(m_device);
    ds.seek(0);

    ds.writeData(VersionMagic, VersionMagicSize);
    ds.write<uint32_t>(m_blockSize);

    if (m_contentIdentifier.empty())
      throw DBException("Opening new database and no content identifier set!");

    if (m_contentIdentifier.utf8Size() > ContentIdentifierStringSize)
      throw DBException("contentIdentifier in BTreeDatabase implementation is greater than maximum identifier length");
    if (m_keySize == 0)
      throw DBException("key size is not set opening a new BTreeDatabase");

    ByteArray contentIdentifier = m_contentIdentifier.utf8Bytes();
    contentIdentifier.resize(ContentIdentifierStringSize, 0);
    ds.writeBytes(contentIdentifier);
    ds.write(m_keySize);