typcache.h

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/*-------------------------------------------------------------------------
 *
 * typcache.h
 *    Type cache definitions.
 *
 * The type cache exists to speed lookup of certain information about data
 * types that is not directly available from a type's pg_type row.
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/utils/typcache.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef TYPCACHE_H
#define TYPCACHE_H

#include "access/tupdesc.h"
#include "fmgr.h"


/* TypeCacheEnumData is an opaque struct known only within typcache.c */
struct TypeCacheEnumData;

typedef struct TypeCacheEntry
{
    /* typeId is the hash lookup key and MUST BE FIRST */
    Oid         type_id;        /* OID of the data type */

    /* some subsidiary information copied from the pg_type row */
    int16       typlen;
    bool        typbyval;
    char        typalign;
    char        typstorage;
    char        typtype;
    Oid         typrelid;

    /*
     * Information obtained from opfamily entries
     *
     * These will be InvalidOid if no match could be found, or if the
     * information hasn't yet been requested.  Also note that for array and
     * composite types, typcache.c checks that the contained types are
     * comparable or hashable before allowing eq_opr etc to become set.
     */
    Oid         btree_opf;      /* the default btree opclass' family */
    Oid         btree_opintype; /* the default btree opclass' opcintype */
    Oid         hash_opf;       /* the default hash opclass' family */
    Oid         hash_opintype;  /* the default hash opclass' opcintype */
    Oid         eq_opr;         /* the equality operator */
    Oid         lt_opr;         /* the less-than operator */
    Oid         gt_opr;         /* the greater-than operator */
    Oid         cmp_proc;       /* the btree comparison function */
    Oid         hash_proc;      /* the hash calculation function */

    /*
     * Pre-set-up fmgr call info for the equality operator, the btree
     * comparison function, and the hash calculation function.  These are kept
     * in the type cache to avoid problems with memory leaks in repeated calls
     * to functions such as array_eq, array_cmp, hash_array.  There is not
     * currently a need to maintain call info for the lt_opr or gt_opr.
     */
    FmgrInfo    eq_opr_finfo;
    FmgrInfo    cmp_proc_finfo;
    FmgrInfo    hash_proc_finfo;

    /*
     * Tuple descriptor if it's a composite type (row type).  NULL if not
     * composite or information hasn't yet been requested.  (NOTE: this is a
     * reference-counted tupledesc.)
     */
    TupleDesc   tupDesc;

    /*
     * Fields computed when TYPECACHE_RANGE_INFO is requested.  Zeroes if not
     * a range type or information hasn't yet been requested.  Note that
     * rng_cmp_proc_finfo could be different from the element type's default
     * btree comparison function.
     */
    struct TypeCacheEntry *rngelemtype; /* range's element type */
    Oid         rng_collation;  /* collation for comparisons, if any */
    FmgrInfo    rng_cmp_proc_finfo;     /* comparison function */
    FmgrInfo    rng_canonical_finfo;    /* canonicalization function, if any */
    FmgrInfo    rng_subdiff_finfo;      /* difference function, if any */

    /* Private data, for internal use of typcache.c only */
    int         flags;          /* flags about what we've computed */

    /*
     * Private information about an enum type.  NULL if not enum or
     * information hasn't been requested.
     */
    struct TypeCacheEnumData *enumData;
} TypeCacheEntry;

/* Bit flags to indicate which fields a given caller needs to have set */
#define TYPECACHE_EQ_OPR            0x0001
#define TYPECACHE_LT_OPR            0x0002
#define TYPECACHE_GT_OPR            0x0004
#define TYPECACHE_CMP_PROC          0x0008
#define TYPECACHE_HASH_PROC         0x0010
#define TYPECACHE_EQ_OPR_FINFO      0x0020
#define TYPECACHE_CMP_PROC_FINFO    0x0040
#define TYPECACHE_HASH_PROC_FINFO   0x0080
#define TYPECACHE_TUPDESC           0x0100
#define TYPECACHE_BTREE_OPFAMILY    0x0200
#define TYPECACHE_HASH_OPFAMILY     0x0400
#define TYPECACHE_RANGE_INFO        0x0800

extern TypeCacheEntry *lookup_type_cache(Oid type_id, int flags);

extern TupleDesc lookup_rowtype_tupdesc(Oid type_id, int32 typmod);

extern TupleDesc lookup_rowtype_tupdesc_noerror(Oid type_id, int32 typmod,
                               bool noError);

extern TupleDesc lookup_rowtype_tupdesc_copy(Oid type_id, int32 typmod);

extern void assign_record_type_typmod(TupleDesc tupDesc);

extern int  compare_values_of_enum(TypeCacheEntry *tcache, Oid arg1, Oid arg2);

#endif   /* TYPCACHE_H */