Function PQputCopyData

src/interfaces/libpq/fe-exec.c:2582–2628

* PQputCopyData - send some data to the backend during COPY IN or COPY BOTH * * Returns 1 if successful, 0 if data could not be sent (only possible * in nonblock mode), or -1 if an error occurs. */

 * in nonblock mode), or -1 if an error occurs.
 */
int
PQputCopyData(PGconn *conn, const char *buffer, int nbytes)
{
	if (!conn)
		return -1;
	if (conn->asyncStatus != PGASYNC_COPY_IN &&
		conn->asyncStatus != PGASYNC_COPY_BOTH)
	{
		appendPQExpBufferStr(&conn->errorMessage,
							 libpq_gettext("no COPY in progress\n"));
		return -1;
	}

	/*
	 * Process any NOTICE or NOTIFY messages that might be pending in the
	 * input buffer.  Since the server might generate many notices during the
	 * COPY, we want to clean those out reasonably promptly to prevent
	 * indefinite expansion of the input buffer.  (Note: the actual read of
	 * input data into the input buffer happens down inside pqSendSome, but
	 * it's not authorized to get rid of the data again.)
	 */
	parseInput(conn);

	if (nbytes > 0)
	{
		/*
		 * Try to flush any previously sent data in preference to growing the
		 * output buffer.  If we can't enlarge the buffer enough to hold the
		 * data, return 0 in the nonblock case, else hard error. (For
		 * simplicity, always assume 5 bytes of overhead.)
		 */
		if ((conn->outBufSize - conn->outCount - 5) < nbytes)
		{
			if (pqFlush(conn) < 0)
				return -1;
			if (pqCheckOutBufferSpace(conn->outCount + 5 + (size_t) nbytes,
									  conn))
				return pqIsnonblocking(conn) ? 0 : -1;
		}
		/* Send the data (too simple to delegate to fe-protocol files) */
		if (pqPutMsgStart('d', conn) < 0 ||
			pqPutnchar(buffer, nbytes, conn) < 0 ||
			pqPutMsgEnd(conn) < 0)
			return -1;
	}
	return 1;
}

/*
 * PQputCopyEnd - send EOF indication to the backend during COPY IN