Hint parsing

server/modules/include/mysqlhint.h

@@ -0,0 +1,110 @@
+#ifndef _MYSQLHINT_H
+#define _MYSQLHINT_H
+/*
+ * This file is distributed as part of the SkySQL Gateway.  It is free
+ * software: you can redistribute it and/or modify it under the terms of the
+ * GNU General Public License as published by the Free Software Foundation,
+ * version 2.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+ * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+ * details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 51
+ * Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Copyright SkySQL Ab 2013
+ */
+
+/*
+ * Revision History
+ *
+ * Date		Who		Description
+ * 17-07-2014	Mark Riddoch	Initial implementation
+ */
+#include <hint.h>
+
+/* Parser tokens for the hint parser */
+typedef enum {
+	TOK_MAXSCALE = 1,
+	TOK_PREPARE,
+	TOK_START,
+	TOK_STOP,
+	TOK_EQUAL,
+	TOK_STRING,
+	TOK_ROUTE,
+	TOK_TO,
+	TOK_MASTER,
+	TOK_SLAVE,
+	TOK_SERVER,
+	TOK_EOL
+} TOKEN_VALUE;
+
+/* The tokenising return type */
+typedef struct {
+	TOKEN_VALUE	token;		// The token itself
+	char		*value;		// The string version of the token
+} HINT_TOKEN;
+
+/**
+ * A named hint set.
+ *
+ * The hint "MaxScale name PREPARE ..." can be used to defined a named set
+ * of hints that can be later applied.
+ */
+typedef struct namedhints {
+	char		*name;	/*< Hintsets name */
+	HINT		*hints;
+	struct namedhints
+			*next;	/*< Next named hint */
+} NAMEDHINTS;
+
+/**
+ * A session meaintains a stack of hints, the hints BEGIN and STOP are used
+ * push hints on and off the stack. The current top of the stack is added to
+ * any statement that does not explicitly define a hint for that signle
+ * statement.
+ */
+typedef struct hintstack {
+	HINT		*hint;
+	struct hintstack
+			*next;
+} HINTSTACK;
+
+/**
+ * The hint instance structure
+ */
+typedef struct {
+	int	sessions;
+} HINT_INSTANCE;
+
+/**
+ * A hint parser session structure
+ */
+typedef struct {
+	DOWNSTREAM	down;
+	GWBUF		*request;
+	int		query_len;
+	HINTSTACK	*stack;
+	NAMEDHINTS	*named_hints;	/* The named hints defined in this session */
+} HINT_SESSION;
+
+/* Some useful macros */
+#define	CURRENT_HINT(session)	((session)->stack ? \
+					(session)->stack->hints : NULL)
+
+/* Hint Parser State Machine */
+#define	HS_INIT		0
+#define	HS_ROUTE	1
+#define	HS_ROUTE1	2
+#define	HS_ROUTE_SERVER	3
+#define	HS_NAME		4
+#define	HS_PVALUE	5
+#define	HS_PREPARE	6
+
+
+extern HINT *hint_parser(HINT_SESSION *session, GWBUF *request);
+
+#endif