common.c

PostgreSQL7.4.6 for Linux

		}
		PQclear(res);
	}

	res = PQexec(pset.db, query);

	if (!AcceptResult(res) && res)
	{
		PQclear(res);
		res = NULL;
	}

	return res;
}



/*
 * PrintNotifications: check for asynchronous notifications, and print them out
 */
static void
PrintNotifications(void)
{
	PGnotify   *notify;

	while ((notify = PQnotifies(pset.db)))
	{
		fprintf(pset.queryFout, gettext("Asynchronous notification \"%s\" received from server process with PID %d.\n"),
				notify->relname, notify->be_pid);
		fflush(pset.queryFout);
		PQfreemem(notify);
	}
}


/*
 * PrintQueryTuples: assuming query result is OK, print its tuples
 *
 * Returns true if successful, false otherwise.
 */
static bool
PrintQueryTuples(const PGresult *results)
{
	/* write output to \g argument, if any */
	if (pset.gfname)
	{
		FILE	   *queryFout_copy = pset.queryFout;
		bool		queryFoutPipe_copy = pset.queryFoutPipe;

		pset.queryFout = stdout;	/* so it doesn't get closed */

		/* open file/pipe */
		if (!setQFout(pset.gfname))
		{
			pset.queryFout = queryFout_copy;
			pset.queryFoutPipe = queryFoutPipe_copy;
			return false;
		}

		printQuery(results, &pset.popt, pset.queryFout);

		/* close file/pipe, restore old setting */
		setQFout(NULL);

		pset.queryFout = queryFout_copy;
		pset.queryFoutPipe = queryFoutPipe_copy;

		free(pset.gfname);
		pset.gfname = NULL;
	}
	else
		printQuery(results, &pset.popt, pset.queryFout);

	return true;
}


/*
 * ProcessCopyResult: if command was a COPY FROM STDIN/TO STDOUT, handle it
 *
 * Note: Utility function for use by SendQuery() only.
 *
 * Returns true if the query executed successfully, false otherwise.
 */
static bool
ProcessCopyResult(PGresult *results)
{
	bool		success = false;

	if (!results)
		return false;

	switch (PQresultStatus(results))
	{
		case PGRES_TUPLES_OK:
		case PGRES_COMMAND_OK:
		case PGRES_EMPTY_QUERY:
			/* nothing to do here */
			success = true;
			break;

		case PGRES_COPY_OUT:
			success = handleCopyOut(pset.db, pset.queryFout);
			break;

		case PGRES_COPY_IN:
			if (pset.cur_cmd_interactive && !QUIET())
				puts(gettext("Enter data to be copied followed by a newline.\n"
							 "End with a backslash and a period on a line by itself."));

			success = handleCopyIn(pset.db, pset.cur_cmd_source,
			  pset.cur_cmd_interactive ? get_prompt(PROMPT_COPY) : NULL);
			break;

		default:
			break;
	}

	/* may need this to recover from conn loss during COPY */
	if (!CheckConnection())
		return false;

	return success;
}


/*
 * PrintQueryResults: print out query results as required
 *
 * Note: Utility function for use by SendQuery() only.
 *
 * Returns true if the query executed successfully, false otherwise.
 */
static bool
PrintQueryResults(PGresult *results)
{
	bool		success = false;

	if (!results)
		return false;

	switch (PQresultStatus(results))
	{
		case PGRES_TUPLES_OK:
			success = PrintQueryTuples(results);
			break;

		case PGRES_COMMAND_OK:
			{
				char		buf[10];

				success = true;
				sprintf(buf, "%u", (unsigned int) PQoidValue(results));
				if (!QUIET())
				{
					if (pset.popt.topt.format == PRINT_HTML)
					{
						fputs("<p>", pset.queryFout);
						html_escaped_print(PQcmdStatus(results),
										   pset.queryFout);
						fputs("</p>\n", pset.queryFout);
					}
					else
						fprintf(pset.queryFout, "%s\n", PQcmdStatus(results));
				}
				SetVariable(pset.vars, "LASTOID", buf);
				break;
			}

		case PGRES_EMPTY_QUERY:
			success = true;
			break;

		case PGRES_COPY_OUT:
		case PGRES_COPY_IN:
			/* nothing to do here */
			success = true;
			break;

		default:
			break;
	}

	fflush(pset.queryFout);

	return success;
}


/*
 * SendQuery: send the query string to the backend
 * (and print out results)
 *
 * Note: This is the "front door" way to send a query. That is, use it to
 * send queries actually entered by the user. These queries will be subject to
 * single step mode.
 * To send "back door" queries (generated by slash commands, etc.) in a
 * controlled way, use PSQLexec().
 *
 * Returns true if the query executed successfully, false otherwise.
 */
bool
SendQuery(const char *query)
{
	PGresult   *results;
	TimevalStruct before,
				after;
	bool		OK;

	if (!pset.db)
	{
		psql_error("You are currently not connected to a database.\n");
		return false;
	}

	if (GetVariableBool(pset.vars, "SINGLESTEP"))
	{
		char		buf[3];

		printf(gettext("***(Single step mode: verify command)*******************************************\n"
					   "%s\n"
					   "***(press return to proceed or enter x and return to cancel)********************\n"),
			   query);
		fflush(stdout);
		if (fgets(buf, sizeof(buf), stdin) != NULL)
			if (buf[0] == 'x')
				return false;
	}
	else if (VariableEquals(pset.vars, "ECHO", "queries"))
	{
		puts(query);
		fflush(stdout);
	}

	SetCancelConn();

	if (PQtransactionStatus(pset.db) == PQTRANS_IDLE &&
		!GetVariableBool(pset.vars, "AUTOCOMMIT") &&
		!is_transact_command(query))
	{
		results = PQexec(pset.db, "BEGIN");
		if (PQresultStatus(results) != PGRES_COMMAND_OK)
		{
			psql_error("%s", PQerrorMessage(pset.db));
			PQclear(results);
			ResetCancelConn();
			return false;
		}
		PQclear(results);
	}

	if (pset.timing)
		GETTIMEOFDAY(&before);

	results = PQexec(pset.db, query);

	/* these operations are included in the timing result: */
	OK = (AcceptResult(results) && ProcessCopyResult(results));

	if (pset.timing)
		GETTIMEOFDAY(&after);

	/* but printing results isn't: */
	if (OK)
		OK = PrintQueryResults(results);

	PQclear(results);

	/* Possible microtiming output */
	if (OK && pset.timing)
		printf(gettext("Time: %.3f ms\n"), DIFF_MSEC(&after, &before));

	/* check for events that may occur during query execution */

	if (pset.encoding != PQclientEncoding(pset.db) &&
		PQclientEncoding(pset.db) >= 0)
	{
		/* track effects of SET CLIENT_ENCODING */
		pset.encoding = PQclientEncoding(pset.db);
		pset.popt.topt.encoding = pset.encoding;
		SetVariable(pset.vars, "ENCODING",
					pg_encoding_to_char(pset.encoding));
	}

	PrintNotifications();

	return OK;
}

/*
 * check whether a query string begins with BEGIN/COMMIT/ROLLBACK/START XACT
 */
static bool
is_transact_command(const char *query)
{
	int			wordlen;

	/*
	 * First we must advance over any whitespace and comments.
	 */
	while (*query)
	{
		if (isspace((unsigned char) *query))
			query++;
		else if (query[0] == '-' && query[1] == '-')
		{
			query += 2;
			while (*query && *query != '\n')
				query++;
		}
		else if (query[0] == '/' && query[1] == '*')
		{
			query += 2;
			while (*query)
			{
				if (query[0] == '*' && query[1] == '/')
				{
					query += 2;
					break;
				}
				else
					query++;
			}
		}
		else
			break;				/* found first token */
	}

	/*
	 * Check word length ("beginx" is not "begin").
	 */
	wordlen = 0;
	while (isalpha((unsigned char) query[wordlen]))
		wordlen++;

	if (wordlen == 5 && strncasecmp(query, "begin", 5) == 0)
		return true;
	if (wordlen == 6 && strncasecmp(query, "commit", 6) == 0)
		return true;
	if (wordlen == 8 && strncasecmp(query, "rollback", 8) == 0)
		return true;
	if (wordlen == 5 && strncasecmp(query, "abort", 5) == 0)
		return true;
	if (wordlen == 3 && strncasecmp(query, "end", 3) == 0)
		return true;
	if (wordlen == 5 && strncasecmp(query, "start", 5) == 0)
		return true;

	return false;
}


char
parse_char(char **buf)
{
	long		l;

	l = strtol(*buf, buf, 0);
	--*buf;
	return (char) l;
}


/*
 * Test if the current user is a database superuser.
 *
 * Note: this will correctly detect superuserness only with a protocol-3.0
 * or newer backend; otherwise it will always say "false".
 */
bool
is_superuser(void)
{
	const char *val;

	if (!pset.db)
		return false;

	val = PQparameterStatus(pset.db, "is_superuser");

	if (val && strcmp(val, "on") == 0)
		return true;

	return false;
}


/*
 * Return the session user of the current connection.
 *
 * Note: this will correctly detect the session user only with a
 * protocol-3.0 or newer backend; otherwise it will return the
 * connection user.
 */
const char *
session_username(void)
{
	const char *val;

	if (!pset.db)
		return NULL;

	val = PQparameterStatus(pset.db, "session_authorization");
	if (val)
		return val;
	else
		return PQuser(pset.db);
}