C++ createPQExpBuffer函数代码示例

/*
 * Run pg_dump on dbname.
 */
static int
runPgDump(const char *dbname)
{
	PQExpBuffer cmd = createPQExpBuffer();
	int			ret;

	appendPQExpBuffer(cmd, SYSTEMQUOTE "\"%s\" %s", pg_dump_bin,
					  pgdumpopts->data);

	/*
	 * If we have a filename, use the undocumented plain-append pg_dump
	 * format.
	 */
	if (filename)
		appendPQExpBuffer(cmd, " -Fa ");
	else
		appendPQExpBuffer(cmd, " -Fp ");

	doShellQuoting(cmd, dbname);

	appendPQExpBuffer(cmd, "%s", SYSTEMQUOTE);

	if (verbose)
		fprintf(stderr, _("%s: running \"%s\"\n"), progname, cmd->data);

	fflush(stdout);
	fflush(stderr);

	ret = system(cmd->data);

	destroyPQExpBuffer(cmd);

	return ret;
}

/*
 * This function takes a function description, e.g. "x" or "x(int)", and
 * issues a query on the given connection to retrieve the function's OID
 * using a cast to regproc or regprocedure (as appropriate). The result,
 * if there is one, is returned at *foid.  Note that we'll fail if the
 * function doesn't exist OR if there are multiple matching candidates
 * OR if there's something syntactically wrong with the function description;
 * unfortunately it can be hard to tell the difference.
 */
static bool
lookup_function_oid(PGconn *conn, const char *desc, Oid *foid)
{
	bool		result = true;
	PQExpBuffer query;
	PGresult   *res;

	query = createPQExpBuffer();
	printfPQExpBuffer(query, "SELECT ");
	appendStringLiteralConn(query, desc, conn);
	appendPQExpBuffer(query, "::pg_catalog.%s::pg_catalog.oid",
					  strchr(desc, '(') ? "regprocedure" : "regproc");

	res = PQexec(conn, query->data);
	if (PQresultStatus(res) == PGRES_TUPLES_OK && PQntuples(res) == 1)
		*foid = atooid(PQgetvalue(res, 0, 0));
	else
	{
		minimal_error_message(res);
		result = false;
	}

	PQclear(res);
	destroyPQExpBuffer(query);

	return result;
}

/*
 * Helper function for dumpXXXConfig().
 */
static void
makeAlterConfigCommand(const char *arrayitem, const char *type, const char *name)
{
	char	   *pos;
	char	   *mine;
	PQExpBuffer buf = createPQExpBuffer();

	mine = strdup(arrayitem);
	pos = strchr(mine, '=');
	if (pos == NULL)
		return;

	*pos = 0;
	appendPQExpBuffer(buf, "ALTER %s %s ", type, fmtId(name));
	appendPQExpBuffer(buf, "SET %s TO ", fmtId(mine));

	/*
	 * Some GUC variable names are 'LIST' type and hence must not be quoted.
	 */
	if (pg_strcasecmp(mine, "DateStyle") == 0
		|| pg_strcasecmp(mine, "search_path") == 0)
		appendPQExpBuffer(buf, "%s", pos + 1);
	else
		appendStringLiteral(buf, pos + 1, false);
	appendPQExpBuffer(buf, ";\n");

	printf("%s", buf->data);
	destroyPQExpBuffer(buf);
	free(mine);
}

/*
 * DoCancelNotifyListen: This function executes a LISTEN or a NOTIFY command, with
 * name in the format N%s_%d_%d, where the %s is replaced by the CDBDumpKey,
 * and the 2 integers are the contentid and dbid.
 */
void
DoCancelNotifyListen(PGconn *pConn,
					 bool bListen,
					 const char *pszCDBDumpKey,
					 int role_id,
					 int db_id,
					 int target_db_id,
					 const char *pszSuffix)
{
	PGresult   *pRes;
	PQExpBuffer q = createPQExpBuffer();
	char	   *pszCmd = bListen ? "LISTEN" : "NOTIFY";

	appendPQExpBuffer(q, "%s N%s_%d_%d",
					  pszCmd, pszCDBDumpKey, role_id, db_id);

	/* this is valid only for restore operations */
	if (target_db_id != -1)
		appendPQExpBuffer(q, "_T%d", target_db_id);

	if (pszSuffix != NULL)
		appendPQExpBuffer(q, "_%s", pszSuffix);

	pRes = PQexec(pConn, q->data);
	if (pRes == NULL || PQresultStatus(pRes) != PGRES_COMMAND_OK)
	{
		mpp_err_msg_cache("%s command failed for for backup key %s, instid %d, segid %d failed : %s",
			   pszCmd, pszCDBDumpKey, role_id, db_id, PQerrorMessage(pConn));
	}

	PQclear(pRes);
	destroyPQExpBuffer(q);
}

/*
 * Dump group memberships from a pre-8.1 server.  It's annoying that we
 * can't share any useful amount of code with the post-8.1 case, but
 * the catalog representations are too different.
 *
 * Note: we expect dumpRoles already created all the roles, but there is
 * no membership yet.
 */
static void
dumpGroups(PGconn *conn)
{
	PQExpBuffer buf = createPQExpBuffer();
	PGresult   *res;
	int			i;

	res = executeQuery(conn,
					   "SELECT groname, grolist FROM pg_group ORDER BY 1");

	if (PQntuples(res) > 0)
		printf("--\n-- Role memberships\n--\n\n");

	for (i = 0; i < PQntuples(res); i++)
	{
		char	   *groname = PQgetvalue(res, i, 0);
		char	   *grolist = PQgetvalue(res, i, 1);
		PGresult   *res2;
		int			j;

		/*
		 * Array representation is {1,2,3} ... convert to (1,2,3)
		 */
		if (strlen(grolist) < 3)
			continue;

		grolist = strdup(grolist);
		grolist[0] = '(';
		grolist[strlen(grolist) - 1] = ')';
		printfPQExpBuffer(buf,
						  "SELECT usename FROM pg_shadow "
						  "WHERE usesysid IN %s ORDER BY 1",
						  grolist);
		free(grolist);

		res2 = executeQuery(conn, buf->data);

		for (j = 0; j < PQntuples(res2); j++)
		{
			char	   *usename = PQgetvalue(res2, j, 0);

			/*
			 * Don't try to grant a role to itself; can happen if old
			 * installation has identically named user and group.
			 */
			if (strcmp(groname, usename) == 0)
				continue;

			printf("GRANT %s", fmtId(groname));
			printf(" TO %s;\n", fmtId(usename));
		}

		PQclear(res2);
	}

	PQclear(res);
	destroyPQExpBuffer(buf);

	printf("\n\n");
}

/*
 * Dump user-and-database-specific configuration
 */
static void
dumpDbRoleConfig(PGconn *conn)
{
	PQExpBuffer buf = createPQExpBuffer();
	PGresult   *res;
	int			i;

	printfPQExpBuffer(buf, "SELECT rolname, datname, unnest(setconfig) "
					  "FROM pg_db_role_setting, pg_authid, pg_database "
		  "WHERE setrole = pg_authid.oid AND setdatabase = pg_database.oid");
	res = executeQuery(conn, buf->data);

	if (PQntuples(res) > 0)
	{
		fprintf(OPF, "--\n-- Per-Database Role Settings \n--\n\n");

		for (i = 0; i < PQntuples(res); i++)
		{
			makeAlterConfigCommand(conn, PQgetvalue(res, i, 2),
								   "ROLE", PQgetvalue(res, i, 0),
								   "DATABASE", PQgetvalue(res, i, 1));
		}

		fprintf(OPF, "\n\n");
	}

	PQclear(res);
	destroyPQExpBuffer(buf);
}

/*
 * Fetches the "CREATE OR REPLACE FUNCTION ..." command that describes the
 * function with the given OID.  If successful, the result is stored in buf.
 */
static bool
get_create_function_cmd(PGconn *conn, Oid oid, PQExpBuffer buf)
{
	bool		result = true;
	PQExpBuffer query;
	PGresult   *res;

	query = createPQExpBuffer();
	printfPQExpBuffer(query, "SELECT pg_catalog.pg_get_functiondef(%u)", oid);

	res = PQexec(conn, query->data);
	if (PQresultStatus(res) == PGRES_TUPLES_OK && PQntuples(res) == 1)
	{
		resetPQExpBuffer(buf);
		appendPQExpBufferStr(buf, PQgetvalue(res, 0, 0));
	}
	else
	{
		minimal_error_message(res);
		result = false;
	}

	PQclear(res);
	destroyPQExpBuffer(query);

	return result;
}

/*
 * Dump database-specific configuration
 */
static void
dumpDatabaseConfig(PGconn *conn, const char *dbname)
{
	PQExpBuffer buf = createPQExpBuffer();
	int			count = 1;

	for (;;)
	{
		PGresult   *res;

		printfPQExpBuffer(buf, "SELECT datconfig[%d] FROM pg_database WHERE datname = ", count);
		appendStringLiteral(buf, dbname, true);
		appendPQExpBuffer(buf, ";");

		res = executeQuery(conn, buf->data);
		if (!PQgetisnull(res, 0, 0))
		{
			makeAlterConfigCommand(PQgetvalue(res, 0, 0), "DATABASE", dbname);
			PQclear(res);
			count++;
		}
		else
		{
			PQclear(res);
			break;
		}
	}

	destroyPQExpBuffer(buf);
}

/*
 * Convert a string value to a dollar quoted literal and append it to
 * the given buffer. If the dqprefix parameter is not NULL then the
 * dollar quote delimiter will begin with that (after the opening $).
 *
 * No escaping is done at all on str, in compliance with the rules
 * for parsing dollar quoted strings.  Also, we need not worry about
 * encoding issues.
 */
void
appendStringLiteralDQ(PQExpBuffer buf, const char *str, const char *dqprefix)
{
	static const char suffixes[] = "_XXXXXXX";
	int			nextchar = 0;
	PQExpBuffer delimBuf = createPQExpBuffer();

	/* start with $ + dqprefix if not NULL */
	appendPQExpBufferChar(delimBuf, '$');
	if (dqprefix)
		appendPQExpBufferStr(delimBuf, dqprefix);

	/*
	 * Make sure we choose a delimiter which (without the trailing $) is not
	 * present in the string being quoted. We don't check with the trailing $
	 * because a string ending in $foo must not be quoted with $foo$.
	 */
	while (strstr(str, delimBuf->data) != NULL)
	{
		appendPQExpBufferChar(delimBuf, suffixes[nextchar++]);
		nextchar %= sizeof(suffixes) - 1;
	}

	/* add trailing $ */
	appendPQExpBufferChar(delimBuf, '$');

	/* quote it and we are all done */
	appendPQExpBufferStr(buf, delimBuf->data);
	appendPQExpBufferStr(buf, str);
	appendPQExpBufferStr(buf, delimBuf->data);

	destroyPQExpBuffer(delimBuf);
}

/*
 * Process non-COPY table data (that is, INSERT commands).
 *
 * The commands have been run together as one long string for compressibility,
 * and we are receiving them in bufferloads with arbitrary boundaries, so we
 * have to locate command boundaries and save partial commands across calls.
 * All state must be kept in AH->sqlparse, not in local variables of this
 * routine.  We assume that AH->sqlparse was filled with zeroes when created.
 *
 * We have to lex the data to the extent of identifying literals and quoted
 * identifiers, so that we can recognize statement-terminating semicolons.
 * We assume that INSERT data will not contain SQL comments, E'' literals,
 * or dollar-quoted strings, so this is much simpler than a full SQL lexer.
 *
 * Note: when restoring from a pre-9.0 dump file, this code is also used to
 * process BLOB COMMENTS data, which has the same problem of containing
 * multiple SQL commands that might be split across bufferloads.  Fortunately,
 * that data won't contain anything complicated to lex either.
 */
static void
ExecuteSimpleCommands(ArchiveHandle *AH, const char *buf, size_t bufLen)
{
	const char *qry = buf;
	const char *eos = buf + bufLen;

	/* initialize command buffer if first time through */
	if (AH->sqlparse.curCmd == NULL)
		AH->sqlparse.curCmd = createPQExpBuffer();

	for (; qry < eos; qry++)
	{
		char		ch = *qry;

		/* For neatness, we skip any newlines between commands */
		if (!(ch == '\n' && AH->sqlparse.curCmd->len == 0))
			appendPQExpBufferChar(AH->sqlparse.curCmd, ch);

		switch (AH->sqlparse.state)
		{
			case SQL_SCAN:		/* Default state == 0, set in _allocAH */
				if (ch == ';')
				{
					/*
					 * We've found the end of a statement. Send it and reset
					 * the buffer.
					 */
					ExecuteSqlCommand(AH, AH->sqlparse.curCmd->data,
									  "could not execute query");
					resetPQExpBuffer(AH->sqlparse.curCmd);
				}
				else if (ch == '\'')
				{
					AH->sqlparse.state = SQL_IN_SINGLE_QUOTE;
					AH->sqlparse.backSlash = false;
				}
				else if (ch == '"')
				{
					AH->sqlparse.state = SQL_IN_DOUBLE_QUOTE;
				}
				break;

			case SQL_IN_SINGLE_QUOTE:
				/* We needn't handle '' specially */
				if (ch == '\'' && !AH->sqlparse.backSlash)
					AH->sqlparse.state = SQL_SCAN;
				else if (ch == '\\' && !AH->public__.std_strings)
					AH->sqlparse.backSlash = !AH->sqlparse.backSlash;
				else
					AH->sqlparse.backSlash = false;
				break;

			case SQL_IN_DOUBLE_QUOTE:
				/* We needn't handle "" specially */
				if (ch == '"')
					AH->sqlparse.state = SQL_SCAN;
				break;
		}
	}
}

/*
 * Build ALTER DEFAULT PRIVILEGES command(s) for single pg_default_acl entry.
 *
 *	type: the object type (TABLES, FUNCTIONS, etc)
 *	nspname: schema name, or NULL for global default privileges
 *	acls: the ACL string fetched from the database
 *	owner: username of privileges owner (will be passed through fmtId)
 *	remoteVersion: version of database
 *
 * Returns TRUE if okay, FALSE if could not parse the acl string.
 * The resulting commands (if any) are appended to the contents of 'sql'.
 */
bool
buildDefaultACLCommands(const char *type, const char *nspname,
						const char *acls, const char *owner,
						int remoteVersion,
						PQExpBuffer sql)
{
	bool		result;
	PQExpBuffer prefix;

	prefix = createPQExpBuffer();

	/*
	 * We incorporate the target role directly into the command, rather than
	 * playing around with SET ROLE or anything like that.	This is so that a
	 * permissions error leads to nothing happening, rather than changing
	 * default privileges for the wrong user.
	 */
	appendPQExpBuffer(prefix, "ALTER DEFAULT PRIVILEGES FOR ROLE %s ",
					  fmtId(owner));
	if (nspname)
		appendPQExpBuffer(prefix, "IN SCHEMA %s ", fmtId(nspname));

	result = buildACLCommands("", NULL,
							  type, acls, owner,
							  prefix->data, remoteVersion,
							  sql);

	destroyPQExpBuffer(prefix);

	return result;
}

int
main(int argc, char** argv)
{
	int	c, i, optindex;

	static struct option long_options[] = {
		{"host", required_argument, NULL, 'h'},
		{"port", required_argument, NULL, 'p'},
		{"username", required_argument, NULL, 'U'},
		{"help", no_argument, NULL, '?'},
		{NULL, 0, NULL, 0}
	};
	
	if (argc == 1 || !strcmp(argv[1], "--help") || !strcmp(argv[1], "-?"))
		help();

	while ((c = getopt_long(argc, argv, "h:p:U:",
							long_options, &optindex)) != -1)
	{
		switch (c)
		{
			case 'h':			/* host for tranlsting oids */
				pghost = optarg;
				break;
			case 'p':			/* port for translating oids */
				pgport = optarg;
				break;
			case 'U':			/* username for translating oids */
				username = optarg;
				break;
			default:
				fprintf(stderr, "Try \"changetrackingdump --help\" for more information.\n");
				exit(1);
		}
	}

	if(pghost)
	{
		conn = DBConnect(pghost, pgport, "template1", username);
	}
	dbQry = createPQExpBuffer();

	for (i = optind; i < argc; i++)
	{
		char *fname = argv[i];
		logFd = open(fname, O_RDONLY | PG_BINARY, 0);

		if (logFd < 0)
		{
			perror(fname);
			continue;
		}
		dumpChangeTracking(fname);
	}

	exit_gracefuly(0);
	
	/* just to avoid a warning */
	return 0;
}

/*
 * Dump user-specific configuration
 */
static void
dumpUserConfig(PGconn *conn, const char *username)
{
	PQExpBuffer buf = createPQExpBuffer();
	int			count = 1;

	for (;;)
	{
		PGresult   *res;

		if (server_version >= 80100)
			printfPQExpBuffer(buf, "SELECT rolconfig[%d] FROM pg_authid WHERE rolname = ", count);
		else
			printfPQExpBuffer(buf, "SELECT useconfig[%d] FROM pg_shadow WHERE usename = ", count);
		appendStringLiteral(buf, username, true);

		res = executeQuery(conn, buf->data);
		if (PQntuples(res) == 1 &&
			!PQgetisnull(res, 0, 0))
		{
			makeAlterConfigCommand(PQgetvalue(res, 0, 0), "ROLE", username);
			PQclear(res);
			count++;
		}
		else
		{
			PQclear(res);
			break;
		}
	}

	destroyPQExpBuffer(buf);
}

/*
 * gets_fromFile
 *
 * Gets a line of noninteractive input from a file (which could be stdin).
 * The result is a malloc'd string, or NULL on EOF or input error.
 *
 * Caller *must* have set up sigint_interrupt_jmp before calling.
 *
 * Note: we re-use a static PQExpBuffer for each call.	This is to avoid
 * leaking memory if interrupted by SIGINT.
 */
char *
gets_fromFile(FILE *source)
{
	static PQExpBuffer buffer = NULL;

	char		line[1024];

	if (buffer == NULL)			/* first time through? */
		buffer = createPQExpBuffer();
	else
		resetPQExpBuffer(buffer);

	for (;;)
	{
		char	   *result;

		/* Enable SIGINT to longjmp to sigint_interrupt_jmp */
		sigint_interrupt_enabled = true;

		/* Get some data */
		result = fgets(line, sizeof(line), source);

		/* Disable SIGINT again */
		sigint_interrupt_enabled = false;

		/* EOF or error? */
		if (result == NULL)
		{
			if (ferror(source))
			{
				psql_error("could not read from input file: %s\n",
						   strerror(errno));
				return NULL;
			}
			break;
		}

		appendPQExpBufferStr(buffer, line);

		if (PQExpBufferBroken(buffer))
		{
			psql_error("out of memory\n");
			return NULL;
		}

		/* EOL? */
		if (buffer->data[buffer->len - 1] == '\n')
		{
			buffer->data[buffer->len - 1] = '\0';
			return pg_strdup(buffer->data);
		}
	}

	if (buffer->len > 0)		/* EOF after reading some bufferload(s) */
		return pg_strdup(buffer->data);

	/* EOF, so return null */
	return NULL;
}

/*
 * ReadBackendBackupFile: This function calls the backend function gp_read_backup_file
 * which reads the contents out of the appropriate file on the database server.
 * If the call succeeds/fails, it returns status code 0/-1, an appropriate error string
 * is inserted into the buffer of pszRtn.
 */
int
ReadBackendBackupFileError(PGconn *pConn, const char *pszBackupDirectory, const char *pszKey,
		BackupFileType fileType, const char *progName, PQExpBuffer pszRtn)
{
	char       *pszFileType;
	PQExpBuffer Qry;
	PGresult   *pRes;
	int status = 0;

	switch (fileType)
	{
		case BFT_BACKUP:
			pszFileType = "0";
			break;
		case BFT_BACKUP_STATUS:
			pszFileType = "1";
			break;
		case BFT_RESTORE_STATUS:
			pszFileType = "2";
			break;
		default:
			appendPQExpBuffer(pszRtn, "Unknown file type passed to ReadBackendBackupFile");
			mpp_err_msg("ERROR", progName, " %s: %d\n", pszRtn->data, fileType);
			return -1;
	}

	Qry = createPQExpBuffer();

	appendPQExpBuffer(Qry, "SELECT * FROM gp_read_backup_file('%s', '%s', %s)",
			StringNotNull(pszBackupDirectory, ""),
			StringNotNull(pszKey, ""),
			pszFileType);

	pRes = PQexec(pConn, Qry->data);
	if (!pRes || PQresultStatus(pRes) != PGRES_TUPLES_OK || PQntuples(pRes) == 0)
	{
		appendPQExpBuffer(pszRtn, "Error executing query %s : %s\n", Qry->data, PQerrorMessage(pConn));
		mpp_err_msg_cache("ERROR", progName, pszRtn->data);
		status = -1;
	}
	else
	{
		char *res = PQgetvalue(pRes, 0, 0);
		appendPQExpBufferStr(pszRtn, res);
		if (strstr(res, "ERROR:") || strstr(res, "[ERROR]"))
		{
			status = -1;
		}
	}

	PQclear(pRes);
	destroyPQExpBuffer(Qry);

	return status;
}