private Boolean closed = false; // true when we are closed
/*
* This opens a large object.
*
* <p>If the object does not exist, then an NpgsqlException is thrown.
*
* @param fp FastPath API for the connection to use
* @param oid of the Large Object to open
* @param mode Mode of opening the large object
* (defined in LargeObjectManager)
* @exception NpgsqlException if a database-access error occurs.
* @see org.postgresql.largeobject.LargeObjectManager
*/
public LargeObject(Fastpath fp, Int32 oid, Int32 mode)
{
this.fp = fp;
this.oid = oid;
FastpathArg[] args = new FastpathArg[2];
args[0] = new FastpathArg(oid);
args[1] = new FastpathArg(mode);
this.fd = fp.GetInteger("lo_open", args);
}
/*
* This method closes the object. You must not call methods in this
* object after this is called.
* @exception NpgsqlException if a database-access error occurs.
*/
public void Close()
{
if (!closed)
{
// finally close
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(fd);
fp.FastpathCall("lo_close", false, args); // true here as we dont care!!
closed = true;
}
}
private Object FastpathV3(Int32 fnid, Boolean resulttype, FastpathArg[] args)
{
// give thread safety
lock (stream)
{
// send the function call
{
Int32 l_msgLen = 0;
l_msgLen += 16;
for (Int32 i = 0; i < args.Length; i++)
{
l_msgLen += args[i].SendSize();
}
stream.WriteByte((Byte)'F');
PGUtil.WriteInt32(stream, l_msgLen);
PGUtil.WriteInt32(stream, fnid);
PGUtil.WriteInt16(stream, 1);
PGUtil.WriteInt16(stream, 1);
PGUtil.WriteInt16(stream, (short)args.Length);
for (Int32 i = 0; i < args.Length; i++)
{
args[i].Send(stream);
}
PGUtil.WriteInt16(stream, 1);
// This is needed, otherwise data can be lost
stream.Flush();
}
// Now handle the result
// Now loop, reading the results
Object result = null; // our result
Exception error = null;
Int32 c;
Boolean l_endQuery = false;
while (!l_endQuery)
{
c = (Char)stream.ReadByte();
switch (c)
{
case 'A': // Asynchronous Notify
Int32 msglen = PGUtil.ReadInt32(stream, buffer);
Int32 pid = PGUtil.ReadInt32(stream, buffer);
String msg = PGUtil.ReadString(stream, queue);
PGUtil.ReadString(stream, queue);
String param = PGUtil.ReadString(stream, queue);
break;
//------------------------------
// Error message returned
case 'E':
NpgsqlError e = new NpgsqlError(stream, buffer, queue);
throw new NpgsqlException(e.ToString());
//------------------------------
// Notice from backend
case 'N':
Int32 l_nlen = PGUtil.ReadInt32(stream, buffer);
conn.Connector.FireNotice(new NpgsqlError(stream, buffer, queue));
break;
case 'V':
Int32 l_msgLen = PGUtil.ReadInt32(stream, buffer);
Int32 l_valueLen = PGUtil.ReadInt32(stream, buffer);
if (l_valueLen == -1)
{
//null value
}
else if (l_valueLen == 0)
{
result = new Byte[0];
}
else
{
// Return an Integer if
if (resulttype)
{
result = PGUtil.ReadInt32(stream, buffer);
}
else
{
Byte[] buf = new Byte[l_valueLen];
Int32 bytes_from_stream = 0;
Int32 total_bytes_read = 0;
Int32 size = l_valueLen;
do
{
bytes_from_stream = stream.Read(buf, total_bytes_read, size);
total_bytes_read += bytes_from_stream;
size -= bytes_from_stream;
}
while (size > 0);
result = buf;
}
}
break;
case 'Z':
//TODO: use size better
if (PGUtil.ReadInt32(stream, buffer) != 5)
{
throw new NpgsqlException("Received Z");
}
//TODO: handle transaction status
Char l_tStatus = (Char)stream.ReadByte();
l_endQuery = true;
break;
default:
throw new NpgsqlException(string.Format("postgresql.fp.protocol received {0}", c));
}
}
if (error != null)
{
throw error;
}
return result;
}
}
/*
* This deletes a large object.
*
* @param oid describing object to delete
* @exception NpgsqlException on error
*/
public void Delete(Int32 oid)
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(oid);
fp.FastpathCall("lo_unlink", false, args);
}
/*
* This creates a large object, returning its OID
*
* @param mode a bitmask describing different attributes of the new object
* @return oid of new object
* @exception NpgsqlException on error
*/
public Int32 Create(Int32 mode)
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(mode);
return(fp.GetInteger("lo_creat", args));
}
/*
* This creates a large object, returning its OID.
*
* <p>It defaults to READWRITE for the new object's attributes.
*
* @return oid of new object
* @exception NpgsqlException on error
*/
public Int32 Create()
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(READWRITE);
return(fp.GetInteger("lo_creat", args));
}
/*
* This method closes the object. You must not call methods in this
* object after this is called.
* @exception NpgsqlException if a database-access error occurs.
*/
public void Close()
{
if (!closed)
{
// finally close
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(fd);
fp.FastpathCall("lo_close", false, args); // true here as we dont care!!
closed = true;
}
}
/*
* This creates a large object, returning its OID
*
* @param mode a bitmask describing different attributes of the new object
* @return oid of new object
* @exception NpgsqlException on error
*/
public Int32 Create(Int32 mode)
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(mode);
return fp.GetInteger("lo_creat", args);
}
/*
* This convenience method assumes that the return value is an Integer
* @param name Function name
* @param args Function arguments
* @return byte[] array containing result
* @exception NpgsqlException if a database-access error occurs or no result
*/
public Byte[] GetData(String name, FastpathArg[] args)
{
return (Byte[])FastpathCall(name, false, args);
}
/*
* Sets the current position within the object.
*
* <p>This is similar to the fseek() call in the standard C library. It
* allows you to have random access to the large object.
*
* @param pos position within object
* @param ref Either SEEK_SET, SEEK_CUR or SEEK_END
* @exception NpgsqlException if a database-access error occurs.
*/
public void Seek(Int32 pos, Int32 refi)
{
FastpathArg[] args = new FastpathArg[3];
args[0] = new FastpathArg(fd);
args[1] = new FastpathArg(pos);
args[2] = new FastpathArg(refi);
fp.FastpathCall("lo_lseek", false, args);
}
/*
* Writes an array to the object
*
* @param buf array to write
* @exception NpgsqlException if a database-access error occurs.
*/
public void Write(Byte[] buf)
{
FastpathArg[] args = new FastpathArg[2];
args[0] = new FastpathArg(fd);
args[1] = new FastpathArg(buf);
fp.FastpathCall("lowrite", false, args);
}
/*
* Reads some data from the object, and return as a byte[] array
*
* @param len number of bytes to read
* @return byte[] array containing data read
* @exception NpgsqlException if a database-access error occurs.
*/
public Byte[] Read(Int32 len)
{
// This is the original method, where the entire block (len bytes)
// is retrieved in one go.
FastpathArg[] args = new FastpathArg[2];
args[0] = new FastpathArg(fd);
args[1] = new FastpathArg(len);
return fp.GetData("loread", args);
}
/*
* @return the current position within the object
* @exception NpgsqlException if a database-access error occurs.
*/
public Int32 Tell()
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(fd);
return(fp.GetInteger("lo_tell", args));
}
/*
* This deletes a large object.
*
* @param oid describing object to delete
* @exception NpgsqlException on error
*/
public void Delete(Int32 oid)
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(oid);
fp.FastpathCall("lo_unlink", false, args);
}
/*
* Send a function call to the PostgreSQL backend by name.
*
* Note: the mapping for the procedure name to function id needs to exist,
* usually to an earlier call to addfunction().
*
* This is the prefered method to call, as function id's can/may change
* between versions of the backend.
*
* For an example of how this works, refer to org.postgresql.largeobject.LargeObject
*
* @param name Function name
* @param resulttype True if the result is an integer, false for other
* results
* @param args FastpathArguments to pass to fastpath
* @return null if no data, Integer if an integer result, or byte[] otherwise
* @exception NpgsqlException if name is unknown or if a database-access error
* occurs.
* @see org.postgresql.largeobject.LargeObject
*/
public Object FastpathCall(String name, Boolean resulttype, FastpathArg[] args)
{
return FastpathCall(GetID(name), resulttype, args);
}
/*
* This convenience method assumes that the return value is an Integer
* @param name Function name
* @param args Function arguments
* @return integer result
* @exception NpgsqlException if a database-access error occurs or no result
*/
public Int32 GetInteger(String name, FastpathArg[] args)
{
Int32 i = (Int32)FastpathCall(name, true, args);
return i;
}
/*
* @return the current position within the object
* @exception NpgsqlException if a database-access error occurs.
*/
public Int32 Tell()
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(fd);
return fp.GetInteger("lo_tell", args);
}
/*
* Send a function call to the PostgreSQL backend
*
* @param fnid Function id
* @param resulttype True if the result is an integer, false for other results
* @param args FastpathArguments to pass to fastpath
* @return null if no data, Integer if an integer result, or byte[] otherwise
* @exception NpgsqlException if a database-access error occurs.
*/
public Object FastpathCall(Int32 fnid, Boolean resulttype, FastpathArg[] args)
{
try
{
return FastpathV3(fnid, resulttype, args);
}
catch (IOException)
{
conn.ClearPool();
throw new NpgsqlException("The Connection is broken.");
}
}
/*
* This creates a large object, returning its OID.
*
* <p>It defaults to READWRITE for the new object's attributes.
*
* @return oid of new object
* @exception NpgsqlException on error
*/
public Int32 Create()
{
FastpathArg[] args = new FastpathArg[1];
args[0] = new FastpathArg(READWRITE);
return fp.GetInteger("lo_creat", args);
}
