C++ resetPQExpBuffer函数代码示例

/*
 * Transfer a user or group name starting at *input into the output buffer,
 * dequoting if needed.  Returns a pointer to just past the input name.
 * The name is taken to end at an unquoted '=' or end of string.
 */
static char *
copyAclUserName(PQExpBuffer output, char *input)
{
	resetPQExpBuffer(output);

	while (*input && *input != '=')
	{
		/*
		 * If user name isn't quoted, then just add it to the output buffer
		 */
		if (*input != '"')
			appendPQExpBufferChar(output, *input++);
		else
		{
			/* Otherwise, it's a quoted username */
			input++;
			/* Loop until we come across an unescaped quote */
			while (!(*input == '"' && *(input + 1) != '"'))
			{
				if (*input == '\0')
					return input;		/* really a syntax error... */

				/*
				 * Quoting convention is to escape " as "".  Keep this code in
				 * sync with putid() in backend's acl.c.
				 */
				if (*input == '"' && *(input + 1) == '"')
					input++;
				appendPQExpBufferChar(output, *input++);
			}
			input++;
		}
	}
	return input;
}

/*
 * pqGets[_append]:
 * get a null-terminated string from the connection,
 * and store it in an expansible PQExpBuffer.
 * If we run out of memory, all of the string is still read,
 * but the excess characters are silently discarded.
 */
static int
pqGets_internal(PQExpBuffer buf, PGconn *conn, bool resetbuffer)
{
	/* Copy conn data to locals for faster search loop */
	char	   *inBuffer = conn->inBuffer;
	int			inCursor = conn->inCursor;
	int			inEnd = conn->inEnd;
	int			slen;

	while (inCursor < inEnd && inBuffer[inCursor])
		inCursor++;

	if (inCursor >= inEnd)
		return EOF;

	slen = inCursor - conn->inCursor;

	if (resetbuffer)
	resetPQExpBuffer(buf);

	appendBinaryPQExpBuffer(buf, inBuffer + conn->inCursor, slen);

	conn->inCursor = ++inCursor;

	if (conn->Pfdebug)
		fprintf(conn->Pfdebug, "From backend> \"%s\"\n",
				buf->data);

	return 0;
}

/*
 *	Attempt to negotiate secure session.
 */
PostgresPollingStatusType
pqsecure_open_client(PGconn *conn)
{
#ifdef USE_SSL
	/* First time through? */
	if (conn->ssl == NULL)
	{
		if (!(conn->ssl = SSL_new(SSL_context)) ||
			!SSL_set_app_data(conn->ssl, conn) ||
			!SSL_set_fd(conn->ssl, conn->sock))
		{
			char	   *err = SSLerrmessage();

			printfPQExpBuffer(&conn->errorMessage,
				   libpq_gettext("could not establish SSL connection: %s\n"),
							  err);
			SSLerrfree(err);
			close_SSL(conn);
			return PGRES_POLLING_FAILED;
		}

		/*
		 * Initialize errorMessage to empty.  This allows open_client_SSL() to
		 * detect whether client_cert_cb() has stored a message.
		 */
		resetPQExpBuffer(&conn->errorMessage);
	}
	/* Begin or continue the actual handshake */
	return open_client_SSL(conn);
#else
	/* shouldn't get here */
	return PGRES_POLLING_FAILED;
#endif
}

/*
 * 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;
}

/*
 * Issue a query on a catalog table, and produce calls to a preassign support
 * function from the result set.
 *
 * The output is a string, containing SQL calls like:
 *
 * SELECT binary_upgrade.preassign_*_oid(<oid>, <other args);
 *
 * 'funcname' is the "preassign_*_oid" function to use.
 * 'sql' is the query to issue. The columns of the result set are passed as
 * arguments to the preassign-support function.
 *
 */
static void
dump_rows(migratorContext *ctx, PQExpBuffer buf, FILE *file, PGconn *conn,
		  const char *sql, const char *funcname)
{
	int			ntups;
	int			ncols;
	int			row;
	int			col;
	PGresult   *res;

	if (file != NULL)
		buf = createPQExpBuffer();

	/*
	 * Add a WHERE or AND clause to filter out built-in objects.
	 *
	 * If the query contains "UNION ALL", then it's the caller's
	 * responsibility to do the filtering. This special case is for the
	 * one more complicated query in get_old_oids() function; all the
	 * other queries are very simple ones.
	 */
	if (strstr(sql, "WHERE ") == NULL)
		res = executeQueryOrDie(ctx, conn, "%s WHERE oid >= %u", sql, FirstNormalObjectId);
	else if (strstr(sql, "UNION ALL") == NULL)
		res = executeQueryOrDie(ctx, conn, "%s AND oid >= %u", sql, FirstNormalObjectId);
	else
		res = executeQueryOrDie(ctx, conn, "%s", sql);

	ntups = PQntuples(res);
	ncols = PQnfields(res);

	for (row = 0; row < ntups; row++)
	{
		appendPQExpBuffer(buf, "SELECT binary_upgrade.%s('%s'",
						  funcname,
						  simple_escape_literal(ctx, conn, PQgetvalue(res, row, 0)));

		for (col = 1; col < ncols; col++)
			appendPQExpBuffer(buf, ", '%s'",
							  simple_escape_literal(ctx, conn, PQgetvalue(res, row, col)));
		appendPQExpBuffer(buf, ");\n");

		if (file)
		{
			fwrite(buf->data, buf->len, 1, file);
			resetPQExpBuffer(buf);
		}
	}
	PQclear(res);

	if (file != NULL)
		destroyPQExpBuffer(buf);
}

/*
 * GSSAPI errors contain two parts; put both into conn->errorMessage.
 */
static void
pg_GSS_error(const char *mprefix, PGconn *conn,
			 OM_uint32 maj_stat, OM_uint32 min_stat)
{
	resetPQExpBuffer(&conn->errorMessage);

	/* Fetch major error codes */
	pg_GSS_error_int(&conn->errorMessage, mprefix, maj_stat, GSS_C_GSS_CODE);

	/* Add the minor codes as well */
	pg_GSS_error_int(&conn->errorMessage, mprefix, min_stat, GSS_C_MECH_CODE);
}

/*
 * Reset a CdbDispatchResult object for possible reuse.
 */
void
cdbdisp_resetResult(CdbDispatchResult *dispatchResult)
{
	PQExpBuffer buf = dispatchResult->resultbuf;
	PGresult **begp = (PGresult **) buf->data;
	PGresult **endp = (PGresult **) (buf->data + buf->len);
	PGresult **p;

	/*
	 * Free the PGresult objects.
	 */
	for (p = begp; p < endp; ++p)
	{
		Assert(*p != NULL);
		PQclear(*p);
	}

	/*
	 * Reset summary indicators.
	 */
	dispatchResult->errcode = 0;
	dispatchResult->errindex = -1;
	dispatchResult->okindex = -1;

	/*
	 * Reset progress indicators.
	 */
	dispatchResult->hasDispatched = false;
	dispatchResult->stillRunning = false;
	dispatchResult->sentSignal = DISPATCH_WAIT_NONE;
	dispatchResult->wasCanceled = false;

	/*
	 * Empty (but don't free) the error message buffer and result buffer.
	 */
	resetPQExpBuffer(dispatchResult->resultbuf);
	resetPQExpBuffer(dispatchResult->error_message);
}

/*
 * gets_fromFile
 *
 * Gets a line of noninteractive input from a file (which could be stdin).
 * The result is a malloc'd string.
 *
 * 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? */
		if (result == NULL)
			break;

		appendPQExpBufferStr(buffer, line);

		/* 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;
}

/*
 * printfPQExpBuffer
 * Format text data under the control of fmt (an sprintf-like format string)
 * and insert it into str.	More space is allocated to str if necessary.
 * This is a convenience routine that does the same thing as
 * resetPQExpBuffer() followed by appendPQExpBuffer().
 */
void
printfPQExpBuffer(PQExpBuffer str, const char *fmt,...)
{
	va_list		args;
	size_t		avail;
	int			nprinted;

	resetPQExpBuffer(str);

	if (PQExpBufferBroken(str))
		return;					/* already failed */

	for (;;)
	{
		/*
		 * Try to format the given string into the available space; but if
		 * there's hardly any space, don't bother trying, just fall through to
		 * enlarge the buffer first.
		 */
		if (str->maxlen > str->len + 16)
		{
			avail = str->maxlen - str->len - 1;
			va_start(args, fmt);
			nprinted = vsnprintf(str->data + str->len, avail,
								 fmt, args);
			va_end(args);

			/*
			 * Note: some versions of vsnprintf return the number of chars
			 * actually stored, but at least one returns -1 on failure. Be
			 * conservative about believing whether the print worked.
			 */
			if (nprinted >= 0 && nprinted < (int) avail - 1)
			{
				/* Success.  Note nprinted does not include trailing null. */
				str->len += nprinted;
				break;
			}
		}
		/* Double the buffer size and try again. */
		if (!enlargePQExpBuffer(str, str->maxlen))
			return;				/* oops, out of memory */
	}
}

/*
 * printfPQExpBuffer
 * Format text data under the control of fmt (an sprintf-like format string)
 * and insert it into str.  More space is allocated to str if necessary.
 * This is a convenience routine that does the same thing as
 * resetPQExpBuffer() followed by appendPQExpBuffer().
 */
void
printfPQExpBuffer(PQExpBuffer str, const char *fmt,...)
{
	va_list		args;
	bool		done;

	resetPQExpBuffer(str);

	if (PQExpBufferBroken(str))
		return;					/* already failed */

	/* Loop in case we have to retry after enlarging the buffer. */
	do
	{
		va_start(args, fmt);
		done = appendPQExpBufferVA(str, fmt, args);
		va_end(args);
	} while (!done);
}

/*
 * cluster_conn_opts()
 *
 * Return standard command-line options for connecting to this cluster when
 * using psql, pg_dump, etc.  Ideally this would match what get_db_conn()
 * sets, but the utilities we need aren't very consistent about the treatment
 * of database name options, so we leave that out.
 *
 * Result is valid until the next call to this function.
 */
char *
cluster_conn_opts(ClusterInfo *cluster)
{
	static PQExpBuffer buf;

	if (buf == NULL)
		buf = createPQExpBuffer();
	else
		resetPQExpBuffer(buf);

	if (cluster->sockdir)
	{
		appendPQExpBufferStr(buf, "--host ");
		appendShellString(buf, cluster->sockdir);
		appendPQExpBufferChar(buf, ' ');
	}
	appendPQExpBuffer(buf, "--port %d --username ", cluster->port);
	appendShellString(buf, os_info.user);

	return buf->data;
}

static void
cluster_all_databases(bool verbose, const char *maintenance_db,
					  const char *host, const char *port,
					  const char *username, enum trivalue prompt_password,
					  const char *progname, bool echo, bool quiet)
{
	PGconn	   *conn;
	PGresult   *result;
	PQExpBufferData connstr;
	int			i;

	conn = connectMaintenanceDatabase(maintenance_db, host, port, username,
									  prompt_password, progname, echo);
	result = executeQuery(conn, "SELECT datname FROM pg_database WHERE datallowconn ORDER BY 1;", progname, echo);
	PQfinish(conn);

	initPQExpBuffer(&connstr);
	for (i = 0; i < PQntuples(result); i++)
	{
		char	   *dbname = PQgetvalue(result, i, 0);

		if (!quiet)
		{
			printf(_("%s: clustering database \"%s\"\n"), progname, dbname);
			fflush(stdout);
		}

		resetPQExpBuffer(&connstr);
		appendPQExpBuffer(&connstr, "dbname=");
		appendConnStrVal(&connstr, dbname);

		cluster_one_database(connstr.data, verbose, NULL,
							 host, port, username, prompt_password,
							 progname, echo);
	}
	termPQExpBuffer(&connstr);

	PQclear(result);
}

/*
 * Emit accumulated history entry to readline's history mechanism,
 * then reset the buffer to empty.
 *
 * Note: we write nothing if history_buf is empty, so extra calls to this
 * function don't hurt.  There must have been at least one line added by
 * pg_append_history before we'll do anything.
 */
void
pg_send_history(PQExpBuffer history_buf)
{
#ifdef USE_READLINE
	static char *prev_hist = NULL;

	char	   *s = history_buf->data;
	int			i;

	/* Trim any trailing \n's (OK to scribble on history_buf) */
	for (i = strlen(s) - 1; i >= 0 && s[i] == '\n'; i--)
		;
	s[i + 1] = '\0';

	if (useHistory && s[0])
	{
		if (((pset.histcontrol & hctl_ignorespace) &&
			 s[0] == ' ') ||
			((pset.histcontrol & hctl_ignoredups) &&
			 prev_hist && strcmp(s, prev_hist) == 0))
		{
			/* Ignore this line as far as history is concerned */
		}
		else
		{
			/* Save each previous line for ignoredups processing */
			if (prev_hist)
				free(prev_hist);
			prev_hist = pg_strdup(s);
			/* And send it to readline */
			add_history(s);
			/* Count lines added to history for use later */
			history_lines_added++;
		}
	}

	resetPQExpBuffer(history_buf);
#endif
}

//.........这里部分代码省略.........
		char		ch = *cp;

		if (ch == '"')
		{
			if (inquotes && cp[1] == '"')
			{
				/* emit one quote, stay in inquotes mode */
				appendPQExpBufferChar(&namebuf, '"');
				cp++;
			}
			else
				inquotes = !inquotes;
			cp++;
		}
		else if (!inquotes && isupper((unsigned char) ch))
		{
			appendPQExpBufferChar(&namebuf,
								  pg_tolower((unsigned char) ch));
			cp++;
		}
		else if (!inquotes && ch == '*')
		{
			appendPQExpBufferStr(&namebuf, ".*");
			cp++;
		}
		else if (!inquotes && ch == '?')
		{
			appendPQExpBufferChar(&namebuf, '.');
			cp++;
		}
		else if (!inquotes && ch == '.')
		{
			/* Found schema/name separator, move current pattern to schema */
			resetPQExpBuffer(&schemabuf);
			appendPQExpBufferStr(&schemabuf, namebuf.data);
			resetPQExpBuffer(&namebuf);
			appendPQExpBufferStr(&namebuf, "^(");
			cp++;
		}
		else if (ch == '$')
		{
			/*
			 * Dollar is always quoted, whether inside quotes or not. The
			 * reason is that it's allowed in SQL identifiers, so there's a
			 * significant use-case for treating it literally, while because
			 * we anchor the pattern automatically there is no use-case for
			 * having it possess its regexp meaning.
			 */
			appendPQExpBufferStr(&namebuf, "\\$");
			cp++;
		}
		else
		{
			/*
			 * Ordinary data character, transfer to pattern
			 *
			 * Inside double quotes, or at all times if force_escape is true,
			 * quote regexp special characters with a backslash to avoid
			 * regexp errors.  Outside quotes, however, let them pass through
			 * as-is; this lets knowledgeable users build regexp expressions
			 * that are more powerful than shell-style patterns.
			 */
			if ((inquotes || force_escape) &&
				strchr("|*+?()[]{}.^$\\", ch))
				appendPQExpBufferChar(&namebuf, '\\');
			i = PQmblen(cp, encoding);

/*
 * This will parse an aclitem string, having the general form
 *		username=privilegecodes/grantor
 * or
 *		group groupname=privilegecodes/grantor
 * (the /grantor part will not be present if pre-7.4 database).
 *
 * The returned grantee string will be the dequoted username or groupname
 * (preceded with "group " in the latter case).  The returned grantor is
 * the dequoted grantor name or empty.	Privilege characters are decoded
 * and split between privileges with grant option (privswgo) and without
 * (privs).
 *
 * Note: for cross-version compatibility, it's important to use ALL when
 * appropriate.
 */
static bool
parseAclItem(const char *item, const char *type,
			 const char *name, const char *subname, int remoteVersion,
			 PQExpBuffer grantee, PQExpBuffer grantor,
			 PQExpBuffer privs, PQExpBuffer privswgo)
{
	char	   *buf;
	bool		all_with_go = true;
	bool		all_without_go = true;
	char	   *eqpos;
	char	   *slpos;
	char	   *pos;

	buf = strdup(item);
	if (!buf)
		return false;

	/* user or group name is string up to = */
	eqpos = copyAclUserName(grantee, buf);
	if (*eqpos != '=')
		return false;

	/* grantor may be listed after / */
	slpos = strchr(eqpos + 1, '/');
	if (slpos)
	{
		*slpos++ = '\0';
		slpos = copyAclUserName(grantor, slpos);
		if (*slpos != '\0')
			return false;
	}
	else
		resetPQExpBuffer(grantor);

	/* privilege codes */
#define CONVERT_PRIV(code, keywd) \
do { \
	if ((pos = strchr(eqpos + 1, code))) \
	{ \
		if (*(pos + 1) == '*') \
		{ \
			AddAcl(privswgo, keywd, subname); \
			all_without_go = false; \
		} \
		else \
		{ \
			AddAcl(privs, keywd, subname); \
			all_with_go = false; \
		} \
	} \
	else \
		all_with_go = all_without_go = false; \
} while (0)

	resetPQExpBuffer(privs);
	resetPQExpBuffer(privswgo);

	if (strcmp(type, "TABLE") == 0 || strcmp(type, "SEQUENCE") == 0 ||
		strcmp(type, "TABLES") == 0 || strcmp(type, "SEQUENCES") == 0)
	{
		CONVERT_PRIV('r', "SELECT");

		if (strcmp(type, "SEQUENCE") == 0 ||
			strcmp(type, "SEQUENCES") == 0)
			/* sequence only */
			CONVERT_PRIV('U', "USAGE");
		else
		{
			/* table only */
			CONVERT_PRIV('a', "INSERT");
			if (remoteVersion >= 70200)
				CONVERT_PRIV('x', "REFERENCES");
			/* rest are not applicable to columns */
			if (subname == NULL)
			{
				if (remoteVersion >= 70200)
				{
					CONVERT_PRIV('d', "DELETE");
					CONVERT_PRIV('t', "TRIGGER");
				}
				if (remoteVersion >= 80400)
					CONVERT_PRIV('D', "TRUNCATE");
			}
		}
//.........这里部分代码省略.........