public PqsqlLargeObject(PqsqlConnection conn)
{
#if CODECONTRACTS
Contract.Requires <ArgumentNullException>(conn != null);
#else
if (conn == null)
{
throw new ArgumentNullException(nameof(conn));
}
#endif
// All large object manipulation using these functions must take place within an SQL transaction block,
// since large object file descriptors are only valid for the duration of a transaction.
// https://www.postgresql.org/docs/current/static/lo-interfaces.html
PGTransactionStatusType transactionStatus = conn.TransactionStatus;
if (transactionStatus != PGTransactionStatusType.PQTRANS_INTRANS &&
transactionStatus != PGTransactionStatusType.PQTRANS_ACTIVE)
{
throw new PqsqlException("PqsqlLargeObject manipulation must take place within an SQL transaction");
}
mConn = conn;
mPGConn = conn.PGConnection;
if (mPGConn == IntPtr.Zero)
{
throw new ArgumentNullException("PqsqlConnection is closed: " + mConn.GetErrorMessage());
}
mOid = 0;
mFd = -1;
mMode = 0;
mPos = -1;
}
public override void Close()
{
if (mFd < 0)
{
return;
}
if (PqsqlWrapper.lo_close(mPGConn, mFd) == -1)
{
// ignore error
}
mFd = -1;
mMode = 0;
mPos = -1;
}
public int Open(uint oid, LoOpen mode)
{
#if CODECONTRACTS
Contract.Requires <ArgumentException>(oid != 0, "Cannot open large object with InvalidOid (0)");
#else
if (oid == 0)
{
throw new ArgumentException("Cannot open large object with InvalidOid (0)");
}
#endif
mFd = PqsqlWrapper.lo_open(mPGConn, oid, (int)mode);
if (mFd < 0)
{
throw new PqsqlException(string.Format(CultureInfo.InvariantCulture, "Cannot open large object {0}: {1}", oid, mConn.GetErrorMessage()));
}
mOid = oid;
mMode = mode;
mPos = 0;
return(mFd);
}
