fe-exec.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

		else
			newTuples = (PGresAttValue **)
				realloc(res->tuples, newSize * sizeof(PGresAttValue *));
		if (!newTuples)
			return FALSE;		/* malloc or realloc failed */
		res->tupArrSize = newSize;
		res->tuples = newTuples;
	}
	res->tuples[res->ntups] = tup;
	res->ntups++;
	return TRUE;
}

/*
 * pqSaveMessageField - save one field of an error or notice message
 */
void
pqSaveMessageField(PGresult *res, char code, const char *value)
{
	PGMessageField *pfield;

	pfield = (PGMessageField *)
		pqResultAlloc(res,
					  sizeof(PGMessageField) + strlen(value),
					  TRUE);
	if (!pfield)
		return;					/* out of memory? */
	pfield->code = code;
	strcpy(pfield->contents, value);
	pfield->next = res->errFields;
	res->errFields = pfield;
}

/*
 * pqSaveParameterStatus - remember parameter status sent by backend
 */
void
pqSaveParameterStatus(PGconn *conn, const char *name, const char *value)
{
	pgParameterStatus *pstatus;
	pgParameterStatus *prev;

	if (conn->Pfdebug)
		fprintf(conn->Pfdebug, "pqSaveParameterStatus: '%s' = '%s'\n",
				name, value);

	/*
	 * Forget any old information about the parameter
	 */
	for (pstatus = conn->pstatus, prev = NULL;
		 pstatus != NULL;
		 prev = pstatus, pstatus = pstatus->next)
	{
		if (strcmp(pstatus->name, name) == 0)
		{
			if (prev)
				prev->next = pstatus->next;
			else
				conn->pstatus = pstatus->next;
			free(pstatus);		/* frees name and value strings too */
			break;
		}
	}

	/*
	 * Store new info as a single malloc block
	 */
	pstatus = (pgParameterStatus *) malloc(sizeof(pgParameterStatus) +
										   strlen(name) +strlen(value) + 2);
	if (pstatus)
	{
		char	   *ptr;

		ptr = ((char *) pstatus) + sizeof(pgParameterStatus);
		pstatus->name = ptr;
		strcpy(ptr, name);
		ptr += strlen(name) + 1;
		pstatus->value = ptr;
		strcpy(ptr, value);
		pstatus->next = conn->pstatus;
		conn->pstatus = pstatus;
	}

	/*
	 * Special hacks: remember client_encoding and standard_conforming_strings,
	 * and convert server version to a numeric form.  We keep the first two of
	 * these in static variables as well, so that PQescapeString and
	 * PQescapeBytea can behave somewhat sanely (at least in single-
	 * connection-using programs).
	 */
	if (strcmp(name, "client_encoding") == 0)
	{
		conn->client_encoding = pg_char_to_encoding(value);
		static_client_encoding = conn->client_encoding;
	}
	else if (strcmp(name, "standard_conforming_strings") == 0)
	{
		conn->std_strings = (strcmp(value, "on") == 0);
		static_std_strings = conn->std_strings;
	}
	else if (strcmp(name, "server_version") == 0)
	{
		int			cnt;
		int			vmaj,
					vmin,
					vrev;

		cnt = sscanf(value, "%d.%d.%d", &vmaj, &vmin, &vrev);

		if (cnt < 2)
			conn->sversion = 0; /* unknown */
		else
		{
			if (cnt == 2)
				vrev = 0;
			conn->sversion = (100 * vmaj + vmin) * 100 + vrev;
		}
	}
}


/*
 * PQsendQuery
 *	 Submit a query, but don't wait for it to finish
 *
 * Returns: 1 if successfully submitted
 *			0 if error (conn->errorMessage is set)
 */
int
PQsendQuery(PGconn *conn, const char *query)
{
	if (!PQsendQueryStart(conn))
		return 0;

	if (!query)
	{
		printfPQExpBuffer(&conn->errorMessage,
						libpq_gettext("command string is a null pointer\n"));
		return 0;
	}

	/* construct the outgoing Query message */
	if (pqPutMsgStart('Q', false, conn) < 0 ||
		pqPuts(query, conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
	{
		pqHandleSendFailure(conn);
		return 0;
	}

	/* remember we are using simple query protocol */
	conn->queryclass = PGQUERY_SIMPLE;

	/*
	 * Give the data a push.  In nonblock mode, don't complain if we're unable
	 * to send it all; PQgetResult() will do any additional flushing needed.
	 */
	if (pqFlush(conn) < 0)
	{
		pqHandleSendFailure(conn);
		return 0;
	}

	/* OK, it's launched! */
	conn->asyncStatus = PGASYNC_BUSY;
	return 1;
}

/*
 * PQsendQueryParams
 *		Like PQsendQuery, but use protocol 3.0 so we can pass parameters
 */
int
PQsendQueryParams(PGconn *conn,
				  const char *command,
				  int nParams,
				  const Oid *paramTypes,
				  const char *const * paramValues,
				  const int *paramLengths,
				  const int *paramFormats,
				  int resultFormat)
{
	if (!PQsendQueryStart(conn))
		return 0;

	if (!command)
	{
		printfPQExpBuffer(&conn->errorMessage,
						libpq_gettext("command string is a null pointer\n"));
		return 0;
	}

	return PQsendQueryGuts(conn,
						   command,
						   "",	/* use unnamed statement */
						   nParams,
						   paramTypes,
						   paramValues,
						   paramLengths,
						   paramFormats,
						   resultFormat);
}

/*
 * PQsendPrepare
 *	 Submit a Parse message, but don't wait for it to finish
 *
 * Returns: 1 if successfully submitted
 *			0 if error (conn->errorMessage is set)
 */
int
PQsendPrepare(PGconn *conn,
			  const char *stmtName, const char *query,
			  int nParams, const Oid *paramTypes)
{
	if (!PQsendQueryStart(conn))
		return 0;

	if (!stmtName)
	{
		printfPQExpBuffer(&conn->errorMessage,
						libpq_gettext("statement name is a null pointer\n"));
		return 0;
	}

	if (!query)
	{
		printfPQExpBuffer(&conn->errorMessage,
						libpq_gettext("command string is a null pointer\n"));
		return 0;
	}

	/* This isn't gonna work on a 2.0 server */
	if (PG_PROTOCOL_MAJOR(conn->pversion) < 3)
	{
		printfPQExpBuffer(&conn->errorMessage,
		 libpq_gettext("function requires at least protocol version 3.0\n"));
		return 0;
	}

	/* construct the Parse message */
	if (pqPutMsgStart('P', false, conn) < 0 ||
		pqPuts(stmtName, conn) < 0 ||
		pqPuts(query, conn) < 0)
		goto sendFailed;

	if (nParams > 0 && paramTypes)
	{
		int			i;

		if (pqPutInt(nParams, 2, conn) < 0)
			goto sendFailed;
		for (i = 0; i < nParams; i++)
		{
			if (pqPutInt(paramTypes[i], 4, conn) < 0)
				goto sendFailed;
		}
	}
	else
	{
		if (pqPutInt(0, 2, conn) < 0)
			goto sendFailed;
	}
	if (pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* construct the Sync message */
	if (pqPutMsgStart('S', false, conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* remember we are doing just a Parse */
	conn->queryclass = PGQUERY_PREPARE;

	/*
	 * Give the data a push.  In nonblock mode, don't complain if we're unable
	 * to send it all; PQgetResult() will do any additional flushing needed.
	 */
	if (pqFlush(conn) < 0)
		goto sendFailed;

	/* OK, it's launched! */
	conn->asyncStatus = PGASYNC_BUSY;
	return 1;

sendFailed:
	pqHandleSendFailure(conn);
	return 0;
}

/*
 * PQsendQueryPrepared
 *		Like PQsendQuery, but execute a previously prepared statement,
 *		using protocol 3.0 so we can pass parameters
 */
int
PQsendQueryPrepared(PGconn *conn,
					const char *stmtName,
					int nParams,
					const char *const * paramValues,
					const int *paramLengths,
					const int *paramFormats,
					int resultFormat)
{
	if (!PQsendQueryStart(conn))
		return 0;

	if (!stmtName)
	{
		printfPQExpBuffer(&conn->errorMessage,
						libpq_gettext("statement name is a null pointer\n"));
		return 0;
	}

	return PQsendQueryGuts(conn,
						   NULL,	/* no command to parse */
						   stmtName,
						   nParams,
						   NULL,	/* no param types */
						   paramValues,
						   paramLengths,
						   paramFormats,
						   resultFormat);
}

/*
 * Common startup code for PQsendQuery and sibling routines
 */
static bool
PQsendQueryStart(PGconn *conn)
{
	if (!conn)
		return false;

	/* clear the error string */
	resetPQExpBuffer(&conn->errorMessage);

	/* Don't try to send if we know there's no live connection. */
	if (conn->status != CONNECTION_OK)
	{
		printfPQExpBuffer(&conn->errorMessage,
						  libpq_gettext("no connection to the server\n"));
		return false;
	}
	/* Can't send while already busy, either. */
	if (conn->asyncStatus != PGASYNC_IDLE)
	{
		printfPQExpBuffer(&conn->errorMessage,
				  libpq_gettext("another command is already in progress\n"));
		return false;
	}

	/* initialize async result-accumulation state */
	conn->result = NULL;
	conn->curTuple = NULL;

	/* ready to send command message */
	return true;
}

/*
 * PQsendQueryGuts
 *		Common code for protocol-3.0 query sending
 *		PQsendQueryStart should be done already
 *
 * command may be NULL to indicate we use an already-prepared statement
 */
static int
PQsendQueryGuts(PGconn *conn,
				const char *command,
				const char *stmtName,
				int nParams,
				const Oid *paramTypes,
				const char *const * paramValues,
				const int *paramLengths,
				const int *paramFormats,
				int resultFormat)
{
	int			i;

	/* This isn't gonna work on a 2.0 server */
	if (PG_PROTOCOL_MAJOR(conn->pversion) < 3)
	{
		printfPQExpBuffer(&conn->errorMessage,
		 libpq_gettext("function requires at least protocol version 3.0\n"));
		return 0;
	}

	/*
	 * We will send Parse (if needed), Bind, Describe Portal, Execute, Sync,
	 * using specified statement name and the unnamed portal.
	 */

	if (command)
	{
		/* construct the Parse message */
		if (pqPutMsgStart('P', false, conn) < 0 ||
			pqPuts(stmtName, conn) < 0 ||
			pqPuts(command, conn) < 0)
			goto sendFailed;
		if (nParams > 0 && paramTypes)
		{
			if (pqPutInt(nParams, 2, conn) < 0)
				goto sendFailed;
			for (i = 0; i < nParams; i++)
			{
				if (pqPutInt(paramTypes[i], 4, conn) < 0)
					goto sendFailed;
			}
		}
		else
		{
			if (pqPutInt(0, 2, conn) < 0)
				goto sendFailed;
		}
		if (pqPutMsgEnd(conn) < 0)
			goto sendFailed;
	}

	/* construct the Bind message */
	if (pqPutMsgStart('B', false, conn) < 0 ||
		pqPuts("", conn) < 0 ||
		pqPuts(stmtName, conn) < 0)
		goto sendFailed;
	if (nParams > 0 && paramFormats)
	{
		if (pqPutInt(nParams, 2, conn) < 0)
			goto sendFailed;
		for (i = 0; i < nParams; i++)
		{
			if (pqPutInt(paramFormats[i], 2, conn) < 0)
				goto sendFailed;
		}
	}
	else
	{
		if (pqPutInt(0, 2, conn) < 0)
			goto sendFailed;
	}
	if (pqPutInt(nParams, 2, conn) < 0)
		goto sendFailed;
	for (i = 0; i < nParams; i++)
	{
		if (paramValues && paramValues[i])
		{
			int			nbytes;

			if (paramFormats && paramFormats[i] != 0)
			{
				/* binary parameter */
				if (paramLengths)
					nbytes = paramLengths[i];
				else
				{
					printfPQExpBuffer(&conn->errorMessage,
									  libpq_gettext("length must be given for binary parameter\n"));
					goto sendFailed;
				}
			}
			else
			{
				/* text parameter, do not use paramLengths */
				nbytes = strlen(paramValues[i]);
			}
			if (pqPutInt(nbytes, 4, conn) < 0 ||
				pqPutnchar(paramValues[i], nbytes, conn) < 0)
				goto sendFailed;
		}
		else
		{
			/* take the param as NULL */
			if (pqPutInt(-1, 4, conn) < 0)
				goto sendFailed;
		}
	}
	if (pqPutInt(1, 2, conn) < 0 ||
		pqPutInt(resultFormat, 2, conn))
		goto sendFailed;
	if (pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* construct the Describe Portal message */
	if (pqPutMsgStart('D', false, conn) < 0 ||
		pqPutc('P', conn) < 0 ||
		pqPuts("", conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* construct the Execute message */
	if (pqPutMsgStart('E', false, conn) < 0 ||
		pqPuts("", conn) < 0 ||
		pqPutInt(0, 4, conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* construct the Sync message */
	if (pqPutMsgStart('S', false, conn) < 0 ||
		pqPutMsgEnd(conn) < 0)
		goto sendFailed;

	/* remember we are using extended query protocol */
	conn->queryclass = PGQUERY_EXTENDED;

	/*
	 * Give the data a push.  In nonblock mode, don't complain if we're unable
	 * to send it all; PQgetResult() will do any additional flushing needed.
	 */
	if (pqFlush(conn) < 0)
		goto sendFailed;

	/* OK, it's launched! */
	conn->asyncStatus = PGASYNC_BUSY;
	return 1;

sendFailed:
	pqHandleSendFailure(conn);
	return 0;
}

/*
 * pqHandleSendFailure: try to clean up after failure to send command.
 *
 * Primarily, what we want to accomplish here is to process an async
 * NOTICE message that the backend might have sent just before it died.
 *
 * NOTE: this routine should only be called in PGASYNC_IDLE state.
 */
void
pqHandleSendFailure(PGconn *conn)
{
	/*
	 * Accept any available input data, ignoring errors.  Note that if
	 * pqReadData decides the backend has closed the channel, it will close
	 * our side of the socket --- that's just what we want here.