regproc.c

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/*-------------------------------------------------------------------------
 *
 * regproc.c
 *    Functions for the built-in types regproc, regclass, regtype, etc.
 *
 * These types are all binary-compatible with type Oid, and rely on Oid
 * for comparison and so forth.  Their only interesting behavior is in
 * special I/O conversion routines.
 *
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/adt/regproc.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>

#include "access/genam.h"
#include "access/heapam.h"
#include "access/htup_details.h"
#include "catalog/indexing.h"
#include "catalog/namespace.h"
#include "catalog/pg_class.h"
#include "catalog/pg_operator.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_ts_config.h"
#include "catalog/pg_ts_dict.h"
#include "catalog/pg_type.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "parser/parse_type.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"
#include "utils/tqual.h"

static char *format_operator_internal(Oid operator_oid, bool force_qualify);
static char *format_procedure_internal(Oid procedure_oid, bool force_qualify);
static void parseNameAndArgTypes(const char *string, bool allowNone,
                     List **names, int *nargs, Oid *argtypes);


/*****************************************************************************
 *   USER I/O ROUTINES                                                       *
 *****************************************************************************/

/*
 * regprocin        - converts "proname" to proc OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_proc entry.
 */
Datum
regprocin(PG_FUNCTION_ARGS)
{
    char       *pro_name_or_oid = PG_GETARG_CSTRING(0);
    RegProcedure result = InvalidOid;
    List       *names;
    FuncCandidateList clist;

    /* '-' ? */
    if (strcmp(pro_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (pro_name_or_oid[0] >= '0' &&
        pro_name_or_oid[0] <= '9' &&
        strspn(pro_name_or_oid, "0123456789") == strlen(pro_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(pro_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /* Else it's a name, possibly schema-qualified */

    /*
     * In bootstrap mode we assume the given name is not schema-qualified, and
     * just search pg_proc for a unique match.  This is needed for
     * initializing other system catalogs (pg_namespace may not exist yet, and
     * certainly there are no schemas other than pg_catalog).
     */
    if (IsBootstrapProcessingMode())
    {
        int         matches = 0;
        Relation    hdesc;
        ScanKeyData skey[1];
        SysScanDesc sysscan;
        HeapTuple   tuple;

        ScanKeyInit(&skey[0],
                    Anum_pg_proc_proname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(pro_name_or_oid));

        hdesc = heap_open(ProcedureRelationId, AccessShareLock);
        sysscan = systable_beginscan(hdesc, ProcedureNameArgsNspIndexId, true,
                                     SnapshotNow, 1, skey);

        while (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
        {
            result = (RegProcedure) HeapTupleGetOid(tuple);
            if (++matches > 1)
                break;
        }

        systable_endscan(sysscan);
        heap_close(hdesc, AccessShareLock);

        if (matches == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_FUNCTION),
                 errmsg("function \"%s\" does not exist", pro_name_or_oid)));

        else if (matches > 1)
            ereport(ERROR,
                    (errcode(ERRCODE_AMBIGUOUS_FUNCTION),
                     errmsg("more than one function named \"%s\"",
                            pro_name_or_oid)));

        PG_RETURN_OID(result);
    }

    /*
     * Normal case: parse the name into components and see if it matches any
     * pg_proc entries in the current search path.
     */
    names = stringToQualifiedNameList(pro_name_or_oid);
    clist = FuncnameGetCandidates(names, -1, NIL, false, false);

    if (clist == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_FUNCTION),
                 errmsg("function \"%s\" does not exist", pro_name_or_oid)));
    else if (clist->next != NULL)
        ereport(ERROR,
                (errcode(ERRCODE_AMBIGUOUS_FUNCTION),
                 errmsg("more than one function named \"%s\"",
                        pro_name_or_oid)));

    result = clist->oid;

    PG_RETURN_OID(result);
}

/*
 * regprocout       - converts proc OID to "pro_name"
 */
Datum
regprocout(PG_FUNCTION_ARGS)
{
    RegProcedure proid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   proctup;

    if (proid == InvalidOid)
    {
        result = pstrdup("-");
        PG_RETURN_CSTRING(result);
    }

    proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(proid));

    if (HeapTupleIsValid(proctup))
    {
        Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(proctup);
        char       *proname = NameStr(procform->proname);

        /*
         * In bootstrap mode, skip the fancy namespace stuff and just return
         * the proc name.  (This path is only needed for debugging output
         * anyway.)
         */
        if (IsBootstrapProcessingMode())
            result = pstrdup(proname);
        else
        {
            char       *nspname;
            FuncCandidateList clist;

            /*
             * Would this proc be found (uniquely!) by regprocin? If not,
             * qualify it.
             */
            clist = FuncnameGetCandidates(list_make1(makeString(proname)),
                                          -1, NIL, false, false);
            if (clist != NULL && clist->next == NULL &&
                clist->oid == proid)
                nspname = NULL;
            else
                nspname = get_namespace_name(procform->pronamespace);

            result = quote_qualified_identifier(nspname, proname);
        }

        ReleaseSysCache(proctup);
    }
    else
    {
        /* If OID doesn't match any pg_proc entry, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", proid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regprocrecv         - converts external binary format to regproc
 */
Datum
regprocrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regprocsend         - converts regproc to binary format
 */
Datum
regprocsend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regprocedurein       - converts "proname(args)" to proc OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_proc entry.
 */
Datum
regprocedurein(PG_FUNCTION_ARGS)
{
    char       *pro_name_or_oid = PG_GETARG_CSTRING(0);
    RegProcedure result = InvalidOid;
    List       *names;
    int         nargs;
    Oid         argtypes[FUNC_MAX_ARGS];
    FuncCandidateList clist;

    /* '-' ? */
    if (strcmp(pro_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (pro_name_or_oid[0] >= '0' &&
        pro_name_or_oid[0] <= '9' &&
        strspn(pro_name_or_oid, "0123456789") == strlen(pro_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(pro_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /*
     * Else it's a name and arguments.  Parse the name and arguments, look up
     * potential matches in the current namespace search list, and scan to see
     * which one exactly matches the given argument types.  (There will not be
     * more than one match.)
     *
     * XXX at present, this code will not work in bootstrap mode, hence this
     * datatype cannot be used for any system column that needs to receive
     * data during bootstrap.
     */
    parseNameAndArgTypes(pro_name_or_oid, false, &names, &nargs, argtypes);

    clist = FuncnameGetCandidates(names, nargs, NIL, false, false);

    for (; clist; clist = clist->next)
    {
        if (memcmp(clist->args, argtypes, nargs * sizeof(Oid)) == 0)
            break;
    }

    if (clist == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_FUNCTION),
                 errmsg("function \"%s\" does not exist", pro_name_or_oid)));

    result = clist->oid;

    PG_RETURN_OID(result);
}

/*
 * format_procedure     - converts proc OID to "pro_name(args)"
 *
 * This exports the useful functionality of regprocedureout for use
 * in other backend modules.  The result is a palloc'd string.
 */
char *
format_procedure(Oid procedure_oid)
{
    return format_procedure_internal(procedure_oid, false);
}

char *
format_procedure_qualified(Oid procedure_oid)
{
    return format_procedure_internal(procedure_oid, true);
}

/*
 * Routine to produce regprocedure names; see format_procedure above.
 *
 * force_qualify says whether to schema-qualify; if true, the name is always
 * qualified regardless of search_path visibility.  Otherwise the name is only
 * qualified if the function is not in path.
 */
static char *
format_procedure_internal(Oid procedure_oid, bool force_qualify)
{
    char       *result;
    HeapTuple   proctup;

    proctup = SearchSysCache1(PROCOID, ObjectIdGetDatum(procedure_oid));

    if (HeapTupleIsValid(proctup))
    {
        Form_pg_proc procform = (Form_pg_proc) GETSTRUCT(proctup);
        char       *proname = NameStr(procform->proname);
        int         nargs = procform->pronargs;
        int         i;
        char       *nspname;
        StringInfoData buf;

        /* XXX no support here for bootstrap mode */

        initStringInfo(&buf);

        /*
         * Would this proc be found (given the right args) by regprocedurein?
         * If not, or if caller requests it, we need to qualify it.
         */
        if (!force_qualify && FunctionIsVisible(procedure_oid))
            nspname = NULL;
        else
            nspname = get_namespace_name(procform->pronamespace);

        appendStringInfo(&buf, "%s(",
                         quote_qualified_identifier(nspname, proname));
        for (i = 0; i < nargs; i++)
        {
            Oid         thisargtype = procform->proargtypes.values[i];

            if (i > 0)
                appendStringInfoChar(&buf, ',');
            appendStringInfoString(&buf,
                                   force_qualify ?
                                   format_type_be_qualified(thisargtype) :
                                   format_type_be(thisargtype));
        }
        appendStringInfoChar(&buf, ')');

        result = buf.data;

        ReleaseSysCache(proctup);
    }
    else
    {
        /* If OID doesn't match any pg_proc entry, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", procedure_oid);
    }

    return result;
}

/*
 * regprocedureout      - converts proc OID to "pro_name(args)"
 */
Datum
regprocedureout(PG_FUNCTION_ARGS)
{
    RegProcedure proid = PG_GETARG_OID(0);
    char       *result;

    if (proid == InvalidOid)
        result = pstrdup("-");
    else
        result = format_procedure(proid);

    PG_RETURN_CSTRING(result);
}

/*
 *      regprocedurerecv            - converts external binary format to regprocedure
 */
Datum
regprocedurerecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regproceduresend            - converts regprocedure to binary format
 */
Datum
regproceduresend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regoperin        - converts "oprname" to operator OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '0' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_operator entry.
 */
Datum
regoperin(PG_FUNCTION_ARGS)
{
    char       *opr_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result = InvalidOid;
    List       *names;
    FuncCandidateList clist;

    /* '0' ? */
    if (strcmp(opr_name_or_oid, "0") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (opr_name_or_oid[0] >= '0' &&
        opr_name_or_oid[0] <= '9' &&
        strspn(opr_name_or_oid, "0123456789") == strlen(opr_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(opr_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /* Else it's a name, possibly schema-qualified */

    /*
     * In bootstrap mode we assume the given name is not schema-qualified, and
     * just search pg_operator for a unique match.  This is needed for
     * initializing other system catalogs (pg_namespace may not exist yet, and
     * certainly there are no schemas other than pg_catalog).
     */
    if (IsBootstrapProcessingMode())
    {
        int         matches = 0;
        Relation    hdesc;
        ScanKeyData skey[1];
        SysScanDesc sysscan;
        HeapTuple   tuple;

        ScanKeyInit(&skey[0],
                    Anum_pg_operator_oprname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(opr_name_or_oid));

        hdesc = heap_open(OperatorRelationId, AccessShareLock);
        sysscan = systable_beginscan(hdesc, OperatorNameNspIndexId, true,
                                     SnapshotNow, 1, skey);

        while (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
        {
            result = HeapTupleGetOid(tuple);
            if (++matches > 1)
                break;
        }

        systable_endscan(sysscan);
        heap_close(hdesc, AccessShareLock);

        if (matches == 0)
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_FUNCTION),
                     errmsg("operator does not exist: %s", opr_name_or_oid)));
        else if (matches > 1)
            ereport(ERROR,
                    (errcode(ERRCODE_AMBIGUOUS_FUNCTION),
                     errmsg("more than one operator named %s",
                            opr_name_or_oid)));

        PG_RETURN_OID(result);
    }

    /*
     * Normal case: parse the name into components and see if it matches any
     * pg_operator entries in the current search path.
     */
    names = stringToQualifiedNameList(opr_name_or_oid);
    clist = OpernameGetCandidates(names, '\0');

    if (clist == NULL)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_FUNCTION),
                 errmsg("operator does not exist: %s", opr_name_or_oid)));
    else if (clist->next != NULL)
        ereport(ERROR,
                (errcode(ERRCODE_AMBIGUOUS_FUNCTION),
                 errmsg("more than one operator named %s",
                        opr_name_or_oid)));

    result = clist->oid;

    PG_RETURN_OID(result);
}

/*
 * regoperout       - converts operator OID to "opr_name"
 */
Datum
regoperout(PG_FUNCTION_ARGS)
{
    Oid         oprid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   opertup;

    if (oprid == InvalidOid)
    {
        result = pstrdup("0");
        PG_RETURN_CSTRING(result);
    }

    opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(oprid));

    if (HeapTupleIsValid(opertup))
    {
        Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
        char       *oprname = NameStr(operform->oprname);

        /*
         * In bootstrap mode, skip the fancy namespace stuff and just return
         * the oper name.  (This path is only needed for debugging output
         * anyway.)
         */
        if (IsBootstrapProcessingMode())
            result = pstrdup(oprname);
        else
        {
            FuncCandidateList clist;

            /*
             * Would this oper be found (uniquely!) by regoperin? If not,
             * qualify it.
             */
            clist = OpernameGetCandidates(list_make1(makeString(oprname)),
                                          '\0');
            if (clist != NULL && clist->next == NULL &&
                clist->oid == oprid)
                result = pstrdup(oprname);
            else
            {
                const char *nspname;

                nspname = get_namespace_name(operform->oprnamespace);
                nspname = quote_identifier(nspname);
                result = (char *) palloc(strlen(nspname) + strlen(oprname) + 2);
                sprintf(result, "%s.%s", nspname, oprname);
            }
        }

        ReleaseSysCache(opertup);
    }
    else
    {
        /*
         * If OID doesn't match any pg_operator entry, return it numerically
         */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", oprid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regoperrecv         - converts external binary format to regoper
 */
Datum
regoperrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regopersend         - converts regoper to binary format
 */
Datum
regopersend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regoperatorin        - converts "oprname(args)" to operator OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '0' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_operator entry.
 */
Datum
regoperatorin(PG_FUNCTION_ARGS)
{
    char       *opr_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result;
    List       *names;
    int         nargs;
    Oid         argtypes[FUNC_MAX_ARGS];

    /* '0' ? */
    if (strcmp(opr_name_or_oid, "0") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (opr_name_or_oid[0] >= '0' &&
        opr_name_or_oid[0] <= '9' &&
        strspn(opr_name_or_oid, "0123456789") == strlen(opr_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(opr_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /*
     * Else it's a name and arguments.  Parse the name and arguments, look up
     * potential matches in the current namespace search list, and scan to see
     * which one exactly matches the given argument types.  (There will not be
     * more than one match.)
     *
     * XXX at present, this code will not work in bootstrap mode, hence this
     * datatype cannot be used for any system column that needs to receive
     * data during bootstrap.
     */
    parseNameAndArgTypes(opr_name_or_oid, true, &names, &nargs, argtypes);
    if (nargs == 1)
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_PARAMETER),
                 errmsg("missing argument"),
                 errhint("Use NONE to denote the missing argument of a unary operator.")));
    if (nargs != 2)
        ereport(ERROR,
                (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
                 errmsg("too many arguments"),
                 errhint("Provide two argument types for operator.")));

    result = OpernameGetOprid(names, argtypes[0], argtypes[1]);

    if (!OidIsValid(result))
        ereport(ERROR,
                (errcode(ERRCODE_UNDEFINED_FUNCTION),
                 errmsg("operator does not exist: %s", opr_name_or_oid)));

    PG_RETURN_OID(result);
}

/*
 * format_operator      - converts operator OID to "opr_name(args)"
 *
 * This exports the useful functionality of regoperatorout for use
 * in other backend modules.  The result is a palloc'd string.
 */
static char *
format_operator_internal(Oid operator_oid, bool force_qualify)
{
    char       *result;
    HeapTuple   opertup;

    opertup = SearchSysCache1(OPEROID, ObjectIdGetDatum(operator_oid));

    if (HeapTupleIsValid(opertup))
    {
        Form_pg_operator operform = (Form_pg_operator) GETSTRUCT(opertup);
        char       *oprname = NameStr(operform->oprname);
        char       *nspname;
        StringInfoData buf;

        /* XXX no support here for bootstrap mode */

        initStringInfo(&buf);

        /*
         * Would this oper be found (given the right args) by regoperatorin?
         * If not, or if caller explicitely requests it, we need to qualify it.
         */
        if (force_qualify || !OperatorIsVisible(operator_oid))
        {
            nspname = get_namespace_name(operform->oprnamespace);
            appendStringInfo(&buf, "%s.",
                             quote_identifier(nspname));
        }

        appendStringInfo(&buf, "%s(", oprname);

        if (operform->oprleft)
            appendStringInfo(&buf, "%s,",
                             force_qualify ?
                             format_type_be_qualified(operform->oprleft) :
                             format_type_be(operform->oprleft));
        else
            appendStringInfo(&buf, "NONE,");

        if (operform->oprright)
            appendStringInfo(&buf, "%s)",
                             force_qualify ?
                             format_type_be_qualified(operform->oprright) :
                             format_type_be(operform->oprright));
        else
            appendStringInfo(&buf, "NONE)");

        result = buf.data;

        ReleaseSysCache(opertup);
    }
    else
    {
        /*
         * If OID doesn't match any pg_operator entry, return it numerically
         */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", operator_oid);
    }

    return result;
}

char *
format_operator(Oid operator_oid)
{
    return format_operator_internal(operator_oid, false);
}

char *
format_operator_qualified(Oid operator_oid)
{
    return format_operator_internal(operator_oid, true);
}

/*
 * regoperatorout       - converts operator OID to "opr_name(args)"
 */
Datum
regoperatorout(PG_FUNCTION_ARGS)
{
    Oid         oprid = PG_GETARG_OID(0);
    char       *result;

    if (oprid == InvalidOid)
        result = pstrdup("0");
    else
        result = format_operator(oprid);

    PG_RETURN_CSTRING(result);
}

/*
 *      regoperatorrecv         - converts external binary format to regoperator
 */
Datum
regoperatorrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regoperatorsend         - converts regoperator to binary format
 */
Datum
regoperatorsend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regclassin       - converts "classname" to class OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_class entry.
 */
Datum
regclassin(PG_FUNCTION_ARGS)
{
    char       *class_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result = InvalidOid;
    List       *names;

    /* '-' ? */
    if (strcmp(class_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (class_name_or_oid[0] >= '0' &&
        class_name_or_oid[0] <= '9' &&
        strspn(class_name_or_oid, "0123456789") == strlen(class_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                        CStringGetDatum(class_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /* Else it's a name, possibly schema-qualified */

    /*
     * In bootstrap mode we assume the given name is not schema-qualified, and
     * just search pg_class for a match.  This is needed for initializing
     * other system catalogs (pg_namespace may not exist yet, and certainly
     * there are no schemas other than pg_catalog).
     */
    if (IsBootstrapProcessingMode())
    {
        Relation    hdesc;
        ScanKeyData skey[1];
        SysScanDesc sysscan;
        HeapTuple   tuple;

        ScanKeyInit(&skey[0],
                    Anum_pg_class_relname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(class_name_or_oid));

        hdesc = heap_open(RelationRelationId, AccessShareLock);
        sysscan = systable_beginscan(hdesc, ClassNameNspIndexId, true,
                                     SnapshotNow, 1, skey);

        if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
            result = HeapTupleGetOid(tuple);
        else
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_TABLE),
               errmsg("relation \"%s\" does not exist", class_name_or_oid)));

        /* We assume there can be only one match */

        systable_endscan(sysscan);
        heap_close(hdesc, AccessShareLock);

        PG_RETURN_OID(result);
    }

    /*
     * Normal case: parse the name into components and see if it matches any
     * pg_class entries in the current search path.
     */
    names = stringToQualifiedNameList(class_name_or_oid);

    /* We might not even have permissions on this relation; don't lock it. */
    result = RangeVarGetRelid(makeRangeVarFromNameList(names), NoLock, false);

    PG_RETURN_OID(result);
}

/*
 * regclassout      - converts class OID to "class_name"
 */
Datum
regclassout(PG_FUNCTION_ARGS)
{
    Oid         classid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   classtup;

    if (classid == InvalidOid)
    {
        result = pstrdup("-");
        PG_RETURN_CSTRING(result);
    }

    classtup = SearchSysCache1(RELOID, ObjectIdGetDatum(classid));

    if (HeapTupleIsValid(classtup))
    {
        Form_pg_class classform = (Form_pg_class) GETSTRUCT(classtup);
        char       *classname = NameStr(classform->relname);

        /*
         * In bootstrap mode, skip the fancy namespace stuff and just return
         * the class name.  (This path is only needed for debugging output
         * anyway.)
         */
        if (IsBootstrapProcessingMode())
            result = pstrdup(classname);
        else
        {
            char       *nspname;

            /*
             * Would this class be found by regclassin? If not, qualify it.
             */
            if (RelationIsVisible(classid))
                nspname = NULL;
            else
                nspname = get_namespace_name(classform->relnamespace);

            result = quote_qualified_identifier(nspname, classname);
        }

        ReleaseSysCache(classtup);
    }
    else
    {
        /* If OID doesn't match any pg_class entry, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", classid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regclassrecv            - converts external binary format to regclass
 */
Datum
regclassrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regclasssend            - converts regclass to binary format
 */
Datum
regclasssend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regtypein        - converts "typename" to type OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_type entry.
 *
 * In bootstrap mode the name must just equal some existing name in pg_type.
 * In normal mode the type name can be specified using the full type syntax
 * recognized by the parser; for example, DOUBLE PRECISION and INTEGER[] will
 * work and be translated to the correct type names.  (We ignore any typmod
 * info generated by the parser, however.)
 */
Datum
regtypein(PG_FUNCTION_ARGS)
{
    char       *typ_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result = InvalidOid;
    int32       typmod;

    /* '-' ? */
    if (strcmp(typ_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (typ_name_or_oid[0] >= '0' &&
        typ_name_or_oid[0] <= '9' &&
        strspn(typ_name_or_oid, "0123456789") == strlen(typ_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(typ_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /* Else it's a type name, possibly schema-qualified or decorated */

    /*
     * In bootstrap mode we assume the given name is not schema-qualified, and
     * just search pg_type for a match.  This is needed for initializing other
     * system catalogs (pg_namespace may not exist yet, and certainly there
     * are no schemas other than pg_catalog).
     */
    if (IsBootstrapProcessingMode())
    {
        Relation    hdesc;
        ScanKeyData skey[1];
        SysScanDesc sysscan;
        HeapTuple   tuple;

        ScanKeyInit(&skey[0],
                    Anum_pg_type_typname,
                    BTEqualStrategyNumber, F_NAMEEQ,
                    CStringGetDatum(typ_name_or_oid));

        hdesc = heap_open(TypeRelationId, AccessShareLock);
        sysscan = systable_beginscan(hdesc, TypeNameNspIndexId, true,
                                     SnapshotNow, 1, skey);

        if (HeapTupleIsValid(tuple = systable_getnext(sysscan)))
            result = HeapTupleGetOid(tuple);
        else
            ereport(ERROR,
                    (errcode(ERRCODE_UNDEFINED_OBJECT),
                     errmsg("type \"%s\" does not exist", typ_name_or_oid)));

        /* We assume there can be only one match */

        systable_endscan(sysscan);
        heap_close(hdesc, AccessShareLock);

        PG_RETURN_OID(result);
    }

    /*
     * Normal case: invoke the full parser to deal with special cases such as
     * array syntax.
     */
    parseTypeString(typ_name_or_oid, &result, &typmod);

    PG_RETURN_OID(result);
}

/*
 * regtypeout       - converts type OID to "typ_name"
 */
Datum
regtypeout(PG_FUNCTION_ARGS)
{
    Oid         typid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   typetup;

    if (typid == InvalidOid)
    {
        result = pstrdup("-");
        PG_RETURN_CSTRING(result);
    }

    typetup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));

    if (HeapTupleIsValid(typetup))
    {
        Form_pg_type typeform = (Form_pg_type) GETSTRUCT(typetup);

        /*
         * In bootstrap mode, skip the fancy namespace stuff and just return
         * the type name.  (This path is only needed for debugging output
         * anyway.)
         */
        if (IsBootstrapProcessingMode())
        {
            char       *typname = NameStr(typeform->typname);

            result = pstrdup(typname);
        }
        else
            result = format_type_be(typid);

        ReleaseSysCache(typetup);
    }
    else
    {
        /* If OID doesn't match any pg_type entry, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", typid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regtyperecv         - converts external binary format to regtype
 */
Datum
regtyperecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regtypesend         - converts regtype to binary format
 */
Datum
regtypesend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regconfigin      - converts "tsconfigname" to tsconfig OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_ts_config entry.
 *
 * This function is not needed in bootstrap mode, so we don't worry about
 * making it work then.
 */
Datum
regconfigin(PG_FUNCTION_ARGS)
{
    char       *cfg_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result;
    List       *names;

    /* '-' ? */
    if (strcmp(cfg_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (cfg_name_or_oid[0] >= '0' &&
        cfg_name_or_oid[0] <= '9' &&
        strspn(cfg_name_or_oid, "0123456789") == strlen(cfg_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                          CStringGetDatum(cfg_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /*
     * Normal case: parse the name into components and see if it matches any
     * pg_ts_config entries in the current search path.
     */
    names = stringToQualifiedNameList(cfg_name_or_oid);

    result = get_ts_config_oid(names, false);

    PG_RETURN_OID(result);
}

/*
 * regconfigout     - converts tsconfig OID to "tsconfigname"
 */
Datum
regconfigout(PG_FUNCTION_ARGS)
{
    Oid         cfgid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   cfgtup;

    if (cfgid == InvalidOid)
    {
        result = pstrdup("-");
        PG_RETURN_CSTRING(result);
    }

    cfgtup = SearchSysCache1(TSCONFIGOID, ObjectIdGetDatum(cfgid));

    if (HeapTupleIsValid(cfgtup))
    {
        Form_pg_ts_config cfgform = (Form_pg_ts_config) GETSTRUCT(cfgtup);
        char       *cfgname = NameStr(cfgform->cfgname);
        char       *nspname;

        /*
         * Would this config be found by regconfigin? If not, qualify it.
         */
        if (TSConfigIsVisible(cfgid))
            nspname = NULL;
        else
            nspname = get_namespace_name(cfgform->cfgnamespace);

        result = quote_qualified_identifier(nspname, cfgname);

        ReleaseSysCache(cfgtup);
    }
    else
    {
        /* If OID doesn't match any pg_ts_config row, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", cfgid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regconfigrecv           - converts external binary format to regconfig
 */
Datum
regconfigrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regconfigsend           - converts regconfig to binary format
 */
Datum
regconfigsend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * regdictionaryin      - converts "tsdictionaryname" to tsdictionary OID
 *
 * We also accept a numeric OID, for symmetry with the output routine.
 *
 * '-' signifies unknown (OID 0).  In all other cases, the input must
 * match an existing pg_ts_dict entry.
 *
 * This function is not needed in bootstrap mode, so we don't worry about
 * making it work then.
 */
Datum
regdictionaryin(PG_FUNCTION_ARGS)
{
    char       *dict_name_or_oid = PG_GETARG_CSTRING(0);
    Oid         result;
    List       *names;

    /* '-' ? */
    if (strcmp(dict_name_or_oid, "-") == 0)
        PG_RETURN_OID(InvalidOid);

    /* Numeric OID? */
    if (dict_name_or_oid[0] >= '0' &&
        dict_name_or_oid[0] <= '9' &&
        strspn(dict_name_or_oid, "0123456789") == strlen(dict_name_or_oid))
    {
        result = DatumGetObjectId(DirectFunctionCall1(oidin,
                                         CStringGetDatum(dict_name_or_oid)));
        PG_RETURN_OID(result);
    }

    /*
     * Normal case: parse the name into components and see if it matches any
     * pg_ts_dict entries in the current search path.
     */
    names = stringToQualifiedNameList(dict_name_or_oid);

    result = get_ts_dict_oid(names, false);

    PG_RETURN_OID(result);
}

/*
 * regdictionaryout     - converts tsdictionary OID to "tsdictionaryname"
 */
Datum
regdictionaryout(PG_FUNCTION_ARGS)
{
    Oid         dictid = PG_GETARG_OID(0);
    char       *result;
    HeapTuple   dicttup;

    if (dictid == InvalidOid)
    {
        result = pstrdup("-");
        PG_RETURN_CSTRING(result);
    }

    dicttup = SearchSysCache1(TSDICTOID, ObjectIdGetDatum(dictid));

    if (HeapTupleIsValid(dicttup))
    {
        Form_pg_ts_dict dictform = (Form_pg_ts_dict) GETSTRUCT(dicttup);
        char       *dictname = NameStr(dictform->dictname);
        char       *nspname;

        /*
         * Would this dictionary be found by regdictionaryin? If not, qualify
         * it.
         */
        if (TSDictionaryIsVisible(dictid))
            nspname = NULL;
        else
            nspname = get_namespace_name(dictform->dictnamespace);

        result = quote_qualified_identifier(nspname, dictname);

        ReleaseSysCache(dicttup);
    }
    else
    {
        /* If OID doesn't match any pg_ts_dict row, return it numerically */
        result = (char *) palloc(NAMEDATALEN);
        snprintf(result, NAMEDATALEN, "%u", dictid);
    }

    PG_RETURN_CSTRING(result);
}

/*
 *      regdictionaryrecv   - converts external binary format to regdictionary
 */
Datum
regdictionaryrecv(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidrecv, so share code */
    return oidrecv(fcinfo);
}

/*
 *      regdictionarysend   - converts regdictionary to binary format
 */
Datum
regdictionarysend(PG_FUNCTION_ARGS)
{
    /* Exactly the same as oidsend, so share code */
    return oidsend(fcinfo);
}


/*
 * text_regclass: convert text to regclass
 *
 * This could be replaced by CoerceViaIO, except that we need to treat
 * text-to-regclass as an implicit cast to support legacy forms of nextval()
 * and related functions.
 */
Datum
text_regclass(PG_FUNCTION_ARGS)
{
    text       *relname = PG_GETARG_TEXT_P(0);
    Oid         result;
    RangeVar   *rv;

    rv = makeRangeVarFromNameList(textToQualifiedNameList(relname));

    /* We might not even have permissions on this relation; don't lock it. */
    result = RangeVarGetRelid(rv, NoLock, false);

    PG_RETURN_OID(result);
}


/*
 * Given a C string, parse it into a qualified-name list.
 */
List *
stringToQualifiedNameList(const char *string)
{
    char       *rawname;
    List       *result = NIL;
    List       *namelist;
    ListCell   *l;

    /* We need a modifiable copy of the input string. */
    rawname = pstrdup(string);

    if (!SplitIdentifierString(rawname, '.', &namelist))
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_NAME),
                 errmsg("invalid name syntax")));

    if (namelist == NIL)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_NAME),
                 errmsg("invalid name syntax")));

    foreach(l, namelist)
    {
        char       *curname = (char *) lfirst(l);

        result = lappend(result, makeString(pstrdup(curname)));
    }

    pfree(rawname);
    list_free(namelist);

    return result;
}

/*****************************************************************************
 *   SUPPORT ROUTINES                                                        *
 *****************************************************************************/

/*
 * Given a C string, parse it into a qualified function or operator name
 * followed by a parenthesized list of type names.  Reduce the
 * type names to an array of OIDs (returned into *nargs and *argtypes;
 * the argtypes array should be of size FUNC_MAX_ARGS).  The function or
 * operator name is returned to *names as a List of Strings.
 *
 * If allowNone is TRUE, accept "NONE" and return it as InvalidOid (this is
 * for unary operators).
 */
static void
parseNameAndArgTypes(const char *string, bool allowNone, List **names,
                     int *nargs, Oid *argtypes)
{
    char       *rawname;
    char       *ptr;
    char       *ptr2;
    char       *typename;
    bool        in_quote;
    bool        had_comma;
    int         paren_count;
    Oid         typeid;
    int32       typmod;

    /* We need a modifiable copy of the input string. */
    rawname = pstrdup(string);

    /* Scan to find the expected left paren; mustn't be quoted */
    in_quote = false;
    for (ptr = rawname; *ptr; ptr++)
    {
        if (*ptr == '"')
            in_quote = !in_quote;
        else if (*ptr == '(' && !in_quote)
            break;
    }
    if (*ptr == '\0')
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                 errmsg("expected a left parenthesis")));

    /* Separate the name and parse it into a list */
    *ptr++ = '\0';
    *names = stringToQualifiedNameList(rawname);

    /* Check for the trailing right parenthesis and remove it */
    ptr2 = ptr + strlen(ptr);
    while (--ptr2 > ptr)
    {
        if (!isspace((unsigned char) *ptr2))
            break;
    }
    if (*ptr2 != ')')
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                 errmsg("expected a right parenthesis")));

    *ptr2 = '\0';

    /* Separate the remaining string into comma-separated type names */
    *nargs = 0;
    had_comma = false;

    for (;;)
    {
        /* allow leading whitespace */
        while (isspace((unsigned char) *ptr))
            ptr++;
        if (*ptr == '\0')
        {
            /* End of string.  Okay unless we had a comma before. */
            if (had_comma)
                ereport(ERROR,
                        (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                         errmsg("expected a type name")));
            break;
        }
        typename = ptr;
        /* Find end of type name --- end of string or comma */
        /* ... but not a quoted or parenthesized comma */
        in_quote = false;
        paren_count = 0;
        for (; *ptr; ptr++)
        {
            if (*ptr == '"')
                in_quote = !in_quote;
            else if (*ptr == ',' && !in_quote && paren_count == 0)
                break;
            else if (!in_quote)
            {
                switch (*ptr)
                {
                    case '(':
                    case '[':
                        paren_count++;
                        break;
                    case ')':
                    case ']':
                        paren_count--;
                        break;
                }
            }
        }
        if (in_quote || paren_count != 0)
            ereport(ERROR,
                    (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
                     errmsg("improper type name")));

        ptr2 = ptr;
        if (*ptr == ',')
        {
            had_comma = true;
            *ptr++ = '\0';
        }
        else
        {
            had_comma = false;
            Assert(*ptr == '\0');
        }
        /* Lop off trailing whitespace */
        while (--ptr2 >= typename)
        {
            if (!isspace((unsigned char) *ptr2))
                break;
            *ptr2 = '\0';
        }

        if (allowNone && pg_strcasecmp(typename, "none") == 0)
        {
            /* Special case for NONE */
            typeid = InvalidOid;
            typmod = -1;
        }
        else
        {
            /* Use full parser to resolve the type name */
            parseTypeString(typename, &typeid, &typmod);
        }
        if (*nargs >= FUNC_MAX_ARGS)
            ereport(ERROR,
                    (errcode(ERRCODE_TOO_MANY_ARGUMENTS),
                     errmsg("too many arguments")));

        argtypes[*nargs] = typeid;
        (*nargs)++;
    }

    pfree(rawname);
}