postgresql/src/include/access/reloptions.h

/*-------------------------------------------------------------------------
 *
 * reloptions.h
 *	  Core support for relation options (pg_class.reloptions)
 *
 * Note: the functions dealing with text-array reloptions values declare
 * them as Datum, not ArrayType *, to avoid needing to include array.h
 * into a lot of low-level code.
 *
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * $PostgreSQL: pgsql/src/include/access/reloptions.h,v 1.7 2009/01/05 17:14:28 alvherre Exp $
 *
 *-------------------------------------------------------------------------
 */
#ifndef RELOPTIONS_H
#define RELOPTIONS_H

#include "nodes/pg_list.h"

/* types supported by reloptions */
typedef enum relopt_type
{
	RELOPT_TYPE_BOOL,
	RELOPT_TYPE_INT,
	RELOPT_TYPE_REAL,
	RELOPT_TYPE_STRING
} relopt_type;

/* kinds supported by reloptions */
typedef enum relopt_kind
{
	RELOPT_KIND_HEAP,
	/* XXX do we need a separate kind for TOAST tables? */
	RELOPT_KIND_BTREE,
	RELOPT_KIND_HASH,
	RELOPT_KIND_GIN,
	RELOPT_KIND_GIST,
	/* if you add a new kind, make sure you update "last_default" too */
	RELOPT_KIND_LAST_DEFAULT = RELOPT_KIND_GIST,
	RELOPT_KIND_MAX = 255
} relopt_kind;

/* generic struct to hold shared data */
typedef struct relopt_gen
{
	const char *name;	/* must be first (used as list termination marker) */
	const char *desc;
	relopt_kind	kind;
	int			namelen;
	relopt_type	type;
} relopt_gen;

/* holds a parsed value */
typedef struct relopt_value
{
	relopt_gen *gen;
	bool		isset;
	union
	{
		bool	bool_val;
		int		int_val;
		double	real_val;
		char   *string_val;	/* allocated separately */
	} values;
} relopt_value;

/* reloptions records for specific variable types */
typedef struct relopt_bool
{
	relopt_gen	gen;
	bool		default_val;
} relopt_bool;
	
typedef struct relopt_int
{
	relopt_gen	gen;
	int			default_val;
	int			min;
	int			max;
} relopt_int;

typedef struct relopt_real
{
	relopt_gen	gen;
	double		default_val;
	double		min;
	double		max;
} relopt_real;

typedef struct relopt_string
{
	relopt_gen	gen;
	int			default_len;
	bool		default_isnull;
	char		default_val[1];	/* variable length */
} relopt_string;

/*
 * These macros exist for the convenience of amoptions writers.  See
 * default_reloptions for an example of the intended usage.  Beware of
 * multiple evaluation of arguments!
 *
 * Most of the time there's no need to call HAVE_RELOPTION manually, but it's
 * possible that an amoptions routine needs to walk the array with a different
 * purpose (say, to compute the size of a struct to allocate beforehand.)
 */
#define HAVE_RELOPTION(optname, option) \
	(pg_strncasecmp(option.gen->name, optname, option.gen->namelen) == 0)

#define HANDLE_INT_RELOPTION(optname, var, option) 					\
	do {															\
		if (HAVE_RELOPTION(optname, option))						\
		{															\
			if (option.isset)										\
				var = option.values.int_val; 						\
			else													\
				var = ((relopt_int *) option.gen)->default_val; 	\
			continue;												\
		}															\
	} while (0)

#define HANDLE_BOOL_RELOPTION(optname, var, option) 				\
	do {															\
		if (HAVE_RELOPTION(optname, option))						\
		{															\
			if (option.isset)										\
				var = option.values.bool_val; 						\
			else													\
				var = ((relopt_bool *) option.gen)->default_val;	\
			continue;												\
		}															\
	} while (0)

#define HANDLE_REAL_RELOPTION(optname, var, option) 				\
	do {															\
		if (HAVE_RELOPTION(optname, option))						\
		{															\
			if (option.isset)										\
				var = option.values.real_val; 						\
			else													\
				var = ((relopt_real *) option.gen)->default_val;	\
			continue;												\
		}															\
	} while (0)

/* Note that this assumes that the variable is already allocated! */
#define HANDLE_STRING_RELOPTION(optname, var, option) 				\
	do {															\
		if (HAVE_RELOPTION(optname, option))						\
		{															\
			relopt_string *optstring = (relopt_string *) option.gen;\
			if (optstring->default_isnull)							\
				var[0] = '\0';										\
			else													\
				strcpy(var,											\
					   option.isset ? option.values.string_val : 	\
					   optstring->default_val);						\
			continue;												\
		}															\
	} while (0)

extern int add_reloption_kind(void);
extern void add_bool_reloption(int kind, char *name, char *desc,
				   bool default_val);
extern void add_int_reloption(int kind, char *name, char *desc,
				  int default_val, int min_val, int max_val);
extern void add_real_reloption(int kind, char *name, char *desc,
				   double default_val, double min_val, double max_val);
extern void add_string_reloption(int kind, char *name, char *desc,
					 char *default_val);
			
extern Datum transformRelOptions(Datum oldOptions, List *defList,
					bool ignoreOids, bool isReset);
extern List *untransformRelOptions(Datum options);
extern relopt_value *parseRelOptions(Datum options, bool validate,
				relopt_kind kind, int *numrelopts);

extern bytea *default_reloptions(Datum reloptions, bool validate,
				   relopt_kind kind);
extern bytea *heap_reloptions(char relkind, Datum reloptions, bool validate);
extern bytea *index_reloptions(RegProcedure amoptions, Datum reloptions,
				bool validate);

#endif   /* RELOPTIONS_H */