sepgsql: update TAP test to use fat comma style

[pgsql.git] / src / backend / utils / adt / misc.c

/*-------------------------------------------------------------------------
 *
 * misc.c
 *
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *        src/backend/utils/adt/misc.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <sys/file.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <math.h>
#include <unistd.h>

#include "access/sysattr.h"
#include "access/table.h"
#include "catalog/pg_tablespace.h"
#include "catalog/pg_type.h"
#include "catalog/system_fk_info.h"
#include "commands/dbcommands.h"
#include "commands/tablespace.h"
#include "common/keywords.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "nodes/miscnodes.h"
#include "parser/parse_type.h"
#include "parser/scansup.h"
#include "pgstat.h"
#include "postmaster/syslogger.h"
#include "rewrite/rewriteHandler.h"
#include "storage/fd.h"
#include "storage/latch.h"
#include "tcop/tcopprot.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/ruleutils.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"


/*
 * structure to cache metadata needed in pg_input_is_valid_common
 */
typedef struct ValidIOData
{
        Oid                     typoid;
        int32           typmod;
        bool            typname_constant;
        Oid                     typiofunc;
        Oid                     typioparam;
        FmgrInfo        inputproc;
} ValidIOData;

static bool pg_input_is_valid_common(FunctionCallInfo fcinfo,
                                                                         text *txt, text *typname,
                                                                         ErrorSaveContext *escontext);


/*
 * Common subroutine for num_nulls() and num_nonnulls().
 * Returns true if successful, false if function should return NULL.
 * If successful, total argument count and number of nulls are
 * returned into *nargs and *nulls.
 */
static bool
count_nulls(FunctionCallInfo fcinfo,
                        int32 *nargs, int32 *nulls)
{
        int32           count = 0;
        int                     i;

        /* Did we get a VARIADIC array argument, or separate arguments? */
        if (get_fn_expr_variadic(fcinfo->flinfo))
        {
                ArrayType  *arr;
                int                     ndims,
                                        nitems,
                                   *dims;
                bits8      *bitmap;

                Assert(PG_NARGS() == 1);

                /*
                 * If we get a null as VARIADIC array argument, we can't say anything
                 * useful about the number of elements, so return NULL.  This behavior
                 * is consistent with other variadic functions - see concat_internal.
                 */
                if (PG_ARGISNULL(0))
                        return false;

                /*
                 * Non-null argument had better be an array.  We assume that any call
                 * context that could let get_fn_expr_variadic return true will have
                 * checked that a VARIADIC-labeled parameter actually is an array.  So
                 * it should be okay to just Assert that it's an array rather than
                 * doing a full-fledged error check.
                 */
                Assert(OidIsValid(get_base_element_type(get_fn_expr_argtype(fcinfo->flinfo, 0))));

                /* OK, safe to fetch the array value */
                arr = PG_GETARG_ARRAYTYPE_P(0);

                /* Count the array elements */
                ndims = ARR_NDIM(arr);
                dims = ARR_DIMS(arr);
                nitems = ArrayGetNItems(ndims, dims);

                /* Count those that are NULL */
                bitmap = ARR_NULLBITMAP(arr);
                if (bitmap)
                {
                        int                     bitmask = 1;

                        for (i = 0; i < nitems; i++)
                        {
                                if ((*bitmap & bitmask) == 0)
                                        count++;

                                bitmask <<= 1;
                                if (bitmask == 0x100)
                                {
                                        bitmap++;
                                        bitmask = 1;
                                }
                        }
                }

                *nargs = nitems;
                *nulls = count;
        }
        else
        {
                /* Separate arguments, so just count 'em */
                for (i = 0; i < PG_NARGS(); i++)
                {
                        if (PG_ARGISNULL(i))
                                count++;
                }

                *nargs = PG_NARGS();
                *nulls = count;
        }

        return true;
}

/*
 * num_nulls()
 *      Count the number of NULL arguments
 */
Datum
pg_num_nulls(PG_FUNCTION_ARGS)
{
        int32           nargs,
                                nulls;

        if (!count_nulls(fcinfo, &nargs, &nulls))
                PG_RETURN_NULL();

        PG_RETURN_INT32(nulls);
}

/*
 * num_nonnulls()
 *      Count the number of non-NULL arguments
 */
Datum
pg_num_nonnulls(PG_FUNCTION_ARGS)
{
        int32           nargs,
                                nulls;

        if (!count_nulls(fcinfo, &nargs, &nulls))
                PG_RETURN_NULL();

        PG_RETURN_INT32(nargs - nulls);
}


/*
 * current_database()
 *      Expose the current database to the user
 */
Datum
current_database(PG_FUNCTION_ARGS)
{
        Name            db;

        db = (Name) palloc(NAMEDATALEN);

        namestrcpy(db, get_database_name(MyDatabaseId));
        PG_RETURN_NAME(db);
}


/*
 * current_query()
 *      Expose the current query to the user (useful in stored procedures)
 *      We might want to use ActivePortal->sourceText someday.
 */
Datum
current_query(PG_FUNCTION_ARGS)
{
        /* there is no easy way to access the more concise 'query_string' */
        if (debug_query_string)
                PG_RETURN_TEXT_P(cstring_to_text(debug_query_string));
        else
                PG_RETURN_NULL();
}

/* Function to find out which databases make use of a tablespace */

Datum
pg_tablespace_databases(PG_FUNCTION_ARGS)
{
        Oid                     tablespaceOid = PG_GETARG_OID(0);
        ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
        char       *location;
        DIR                *dirdesc;
        struct dirent *de;

        InitMaterializedSRF(fcinfo, MAT_SRF_USE_EXPECTED_DESC);

        if (tablespaceOid == GLOBALTABLESPACE_OID)
        {
                ereport(WARNING,
                                (errmsg("global tablespace never has databases")));
                /* return empty tuplestore */
                return (Datum) 0;
        }

        if (tablespaceOid == DEFAULTTABLESPACE_OID)
                location = "base";
        else
                location = psprintf("%s/%u/%s", PG_TBLSPC_DIR, tablespaceOid,
                                                        TABLESPACE_VERSION_DIRECTORY);

        dirdesc = AllocateDir(location);

        if (!dirdesc)
        {
                /* the only expected error is ENOENT */
                if (errno != ENOENT)
                        ereport(ERROR,
                                        (errcode_for_file_access(),
                                         errmsg("could not open directory \"%s\": %m",
                                                        location)));
                ereport(WARNING,
                                (errmsg("%u is not a tablespace OID", tablespaceOid)));
                /* return empty tuplestore */
                return (Datum) 0;
        }

        while ((de = ReadDir(dirdesc, location)) != NULL)
        {
                Oid                     datOid = atooid(de->d_name);
                char       *subdir;
                bool            isempty;
                Datum           values[1];
                bool            nulls[1];

                /* this test skips . and .., but is awfully weak */
                if (!datOid)
                        continue;

                /* if database subdir is empty, don't report tablespace as used */

                subdir = psprintf("%s/%s", location, de->d_name);
                isempty = directory_is_empty(subdir);
                pfree(subdir);

                if (isempty)
                        continue;                       /* indeed, nothing in it */

                values[0] = ObjectIdGetDatum(datOid);
                nulls[0] = false;

                tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc,
                                                         values, nulls);
        }

        FreeDir(dirdesc);
        return (Datum) 0;
}


/*
 * pg_tablespace_location - get location for a tablespace
 */
Datum
pg_tablespace_location(PG_FUNCTION_ARGS)
{
        Oid                     tablespaceOid = PG_GETARG_OID(0);
        char            sourcepath[MAXPGPATH];
        char            targetpath[MAXPGPATH];
        int                     rllen;
        struct stat st;

        /*
         * It's useful to apply this function to pg_class.reltablespace, wherein
         * zero means "the database's default tablespace".  So, rather than
         * throwing an error for zero, we choose to assume that's what is meant.
         */
        if (tablespaceOid == InvalidOid)
                tablespaceOid = MyDatabaseTableSpace;

        /*
         * Return empty string for the cluster's default tablespaces
         */
        if (tablespaceOid == DEFAULTTABLESPACE_OID ||
                tablespaceOid == GLOBALTABLESPACE_OID)
                PG_RETURN_TEXT_P(cstring_to_text(""));

        /*
         * Find the location of the tablespace by reading the symbolic link that
         * is in pg_tblspc/<oid>.
         */
        snprintf(sourcepath, sizeof(sourcepath), "%s/%u", PG_TBLSPC_DIR, tablespaceOid);

        /*
         * Before reading the link, check if the source path is a link or a
         * junction point.  Note that a directory is possible for a tablespace
         * created with allow_in_place_tablespaces enabled.  If a directory is
         * found, a relative path to the data directory is returned.
         */
        if (lstat(sourcepath, &st) < 0)
        {
                ereport(ERROR,
                                (errcode_for_file_access(),
                                 errmsg("could not stat file \"%s\": %m",
                                                sourcepath)));
        }

        if (!S_ISLNK(st.st_mode))
                PG_RETURN_TEXT_P(cstring_to_text(sourcepath));

        /*
         * In presence of a link or a junction point, return the path pointing to.
         */
        rllen = readlink(sourcepath, targetpath, sizeof(targetpath));
        if (rllen < 0)
                ereport(ERROR,
                                (errcode_for_file_access(),
                                 errmsg("could not read symbolic link \"%s\": %m",
                                                sourcepath)));
        if (rllen >= sizeof(targetpath))
                ereport(ERROR,
                                (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
                                 errmsg("symbolic link \"%s\" target is too long",
                                                sourcepath)));
        targetpath[rllen] = '\0';

        PG_RETURN_TEXT_P(cstring_to_text(targetpath));
}

/*
 * pg_sleep - delay for N seconds
 */
Datum
pg_sleep(PG_FUNCTION_ARGS)
{
        float8          secs = PG_GETARG_FLOAT8(0);
        float8          endtime;

        /*
         * We sleep using WaitLatch, to ensure that we'll wake up promptly if an
         * important signal (such as SIGALRM or SIGINT) arrives.  Because
         * WaitLatch's upper limit of delay is INT_MAX milliseconds, and the user
         * might ask for more than that, we sleep for at most 10 minutes and then
         * loop.
         *
         * By computing the intended stop time initially, we avoid accumulation of
         * extra delay across multiple sleeps.  This also ensures we won't delay
         * less than the specified time when WaitLatch is terminated early by a
         * non-query-canceling signal such as SIGHUP.
         */
#define GetNowFloat()   ((float8) GetCurrentTimestamp() / 1000000.0)

        endtime = GetNowFloat() + secs;

        for (;;)
        {
                float8          delay;
                long            delay_ms;

                CHECK_FOR_INTERRUPTS();

                delay = endtime - GetNowFloat();
                if (delay >= 600.0)
                        delay_ms = 600000;
                else if (delay > 0.0)
                        delay_ms = (long) ceil(delay * 1000.0);
                else
                        break;

                (void) WaitLatch(MyLatch,
                                                 WL_LATCH_SET | WL_TIMEOUT | WL_EXIT_ON_PM_DEATH,
                                                 delay_ms,
                                                 WAIT_EVENT_PG_SLEEP);
                ResetLatch(MyLatch);
        }

        PG_RETURN_VOID();
}

/* Function to return the list of grammar keywords */
Datum
pg_get_keywords(PG_FUNCTION_ARGS)
{
        FuncCallContext *funcctx;

        if (SRF_IS_FIRSTCALL())
        {
                MemoryContext oldcontext;
                TupleDesc       tupdesc;

                funcctx = SRF_FIRSTCALL_INIT();
                oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

                if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
                        elog(ERROR, "return type must be a row type");
                funcctx->tuple_desc = tupdesc;
                funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);

                MemoryContextSwitchTo(oldcontext);
        }

        funcctx = SRF_PERCALL_SETUP();

        if (funcctx->call_cntr < ScanKeywords.num_keywords)
        {
                char       *values[5];
                HeapTuple       tuple;

                /* cast-away-const is ugly but alternatives aren't much better */
                values[0] = unconstify(char *,
                                                           GetScanKeyword(funcctx->call_cntr,
                                                                                          &ScanKeywords));

                switch (ScanKeywordCategories[funcctx->call_cntr])
                {
                        case UNRESERVED_KEYWORD:
                                values[1] = "U";
                                values[3] = _("unreserved");
                                break;
                        case COL_NAME_KEYWORD:
                                values[1] = "C";
                                values[3] = _("unreserved (cannot be function or type name)");
                                break;
                        case TYPE_FUNC_NAME_KEYWORD:
                                values[1] = "T";
                                values[3] = _("reserved (can be function or type name)");
                                break;
                        case RESERVED_KEYWORD:
                                values[1] = "R";
                                values[3] = _("reserved");
                                break;
                        default:                        /* shouldn't be possible */
                                values[1] = NULL;
                                values[3] = NULL;
                                break;
                }

                if (ScanKeywordBareLabel[funcctx->call_cntr])
                {
                        values[2] = "true";
                        values[4] = _("can be bare label");
                }
                else
                {
                        values[2] = "false";
                        values[4] = _("requires AS");
                }

                tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);

                SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
        }

        SRF_RETURN_DONE(funcctx);
}


/* Function to return the list of catalog foreign key relationships */
Datum
pg_get_catalog_foreign_keys(PG_FUNCTION_ARGS)
{
        FuncCallContext *funcctx;
        FmgrInfo   *arrayinp;

        if (SRF_IS_FIRSTCALL())
        {
                MemoryContext oldcontext;
                TupleDesc       tupdesc;

                funcctx = SRF_FIRSTCALL_INIT();
                oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);

                if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
                        elog(ERROR, "return type must be a row type");
                funcctx->tuple_desc = BlessTupleDesc(tupdesc);

                /*
                 * We use array_in to convert the C strings in sys_fk_relationships[]
                 * to text arrays.  But we cannot use DirectFunctionCallN to call
                 * array_in, and it wouldn't be very efficient if we could.  Fill an
                 * FmgrInfo to use for the call.
                 */
                arrayinp = (FmgrInfo *) palloc(sizeof(FmgrInfo));
                fmgr_info(F_ARRAY_IN, arrayinp);
                funcctx->user_fctx = arrayinp;

                MemoryContextSwitchTo(oldcontext);
        }

        funcctx = SRF_PERCALL_SETUP();
        arrayinp = (FmgrInfo *) funcctx->user_fctx;

        if (funcctx->call_cntr < lengthof(sys_fk_relationships))
        {
                const SysFKRelationship *fkrel = &sys_fk_relationships[funcctx->call_cntr];
                Datum           values[6];
                bool            nulls[6];
                HeapTuple       tuple;

                memset(nulls, false, sizeof(nulls));

                values[0] = ObjectIdGetDatum(fkrel->fk_table);
                values[1] = FunctionCall3(arrayinp,
                                                                  CStringGetDatum(fkrel->fk_columns),
                                                                  ObjectIdGetDatum(TEXTOID),
                                                                  Int32GetDatum(-1));
                values[2] = ObjectIdGetDatum(fkrel->pk_table);
                values[3] = FunctionCall3(arrayinp,
                                                                  CStringGetDatum(fkrel->pk_columns),
                                                                  ObjectIdGetDatum(TEXTOID),
                                                                  Int32GetDatum(-1));
                values[4] = BoolGetDatum(fkrel->is_array);
                values[5] = BoolGetDatum(fkrel->is_opt);

                tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);

                SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
        }

        SRF_RETURN_DONE(funcctx);
}


/*
 * Return the type of the argument.
 */
Datum
pg_typeof(PG_FUNCTION_ARGS)
{
        PG_RETURN_OID(get_fn_expr_argtype(fcinfo->flinfo, 0));
}


/*
 * Return the base type of the argument.
 *              If the given type is a domain, return its base type;
 *              otherwise return the type's own OID.
 *              Return NULL if the type OID doesn't exist or points to a
 *              non-existent base type.
 *
 * This is a SQL-callable version of getBaseType().  Unlike that function,
 * we don't want to fail for a bogus type OID; this is helpful to keep race
 * conditions from turning into query failures when scanning the catalogs.
 * Hence we need our own implementation.
 */
Datum
pg_basetype(PG_FUNCTION_ARGS)
{
        Oid                     typid = PG_GETARG_OID(0);

        /*
         * We loop to find the bottom base type in a stack of domains.
         */
        for (;;)
        {
                HeapTuple       tup;
                Form_pg_type typTup;

                tup = SearchSysCache1(TYPEOID, ObjectIdGetDatum(typid));
                if (!HeapTupleIsValid(tup))
                        PG_RETURN_NULL();       /* return NULL for bogus OID */
                typTup = (Form_pg_type) GETSTRUCT(tup);
                if (typTup->typtype != TYPTYPE_DOMAIN)
                {
                        /* Not a domain, so done */
                        ReleaseSysCache(tup);
                        break;
                }

                typid = typTup->typbasetype;
                ReleaseSysCache(tup);
        }

        PG_RETURN_OID(typid);
}


/*
 * Implementation of the COLLATE FOR expression; returns the collation
 * of the argument.
 */
Datum
pg_collation_for(PG_FUNCTION_ARGS)
{
        Oid                     typeid;
        Oid                     collid;

        typeid = get_fn_expr_argtype(fcinfo->flinfo, 0);
        if (!typeid)
                PG_RETURN_NULL();
        if (!type_is_collatable(typeid) && typeid != UNKNOWNOID)
                ereport(ERROR,
                                (errcode(ERRCODE_DATATYPE_MISMATCH),
                                 errmsg("collations are not supported by type %s",
                                                format_type_be(typeid))));

        collid = PG_GET_COLLATION();
        if (!collid)
                PG_RETURN_NULL();
        PG_RETURN_TEXT_P(cstring_to_text(generate_collation_name(collid)));
}


/*
 * pg_relation_is_updatable - determine which update events the specified
 * relation supports.
 *
 * This relies on relation_is_updatable() in rewriteHandler.c, which see
 * for additional information.
 */
Datum
pg_relation_is_updatable(PG_FUNCTION_ARGS)
{
        Oid                     reloid = PG_GETARG_OID(0);
        bool            include_triggers = PG_GETARG_BOOL(1);

        PG_RETURN_INT32(relation_is_updatable(reloid, NIL, include_triggers, NULL));
}

/*
 * pg_column_is_updatable - determine whether a column is updatable
 *
 * This function encapsulates the decision about just what
 * information_schema.columns.is_updatable actually means.  It's not clear
 * whether deletability of the column's relation should be required, so
 * we want that decision in C code where we could change it without initdb.
 */
Datum
pg_column_is_updatable(PG_FUNCTION_ARGS)
{
        Oid                     reloid = PG_GETARG_OID(0);
        AttrNumber      attnum = PG_GETARG_INT16(1);
        AttrNumber      col = attnum - FirstLowInvalidHeapAttributeNumber;
        bool            include_triggers = PG_GETARG_BOOL(2);
        int                     events;

        /* System columns are never updatable */
        if (attnum <= 0)
                PG_RETURN_BOOL(false);

        events = relation_is_updatable(reloid, NIL, include_triggers,
                                                                   bms_make_singleton(col));

        /* We require both updatability and deletability of the relation */
#define REQ_EVENTS ((1 << CMD_UPDATE) | (1 << CMD_DELETE))

        PG_RETURN_BOOL((events & REQ_EVENTS) == REQ_EVENTS);
}


/*
 * pg_input_is_valid - test whether string is valid input for datatype.
 *
 * Returns true if OK, false if not.
 *
 * This will only work usefully if the datatype's input function has been
 * updated to return "soft" errors via errsave/ereturn.
 */
Datum
pg_input_is_valid(PG_FUNCTION_ARGS)
{
        text       *txt = PG_GETARG_TEXT_PP(0);
        text       *typname = PG_GETARG_TEXT_PP(1);
        ErrorSaveContext escontext = {T_ErrorSaveContext};

        PG_RETURN_BOOL(pg_input_is_valid_common(fcinfo, txt, typname,
                                                                                        &escontext));
}

/*
 * pg_input_error_info - test whether string is valid input for datatype.
 *
 * Returns NULL if OK, else the primary message, detail message, hint message
 * and sql error code from the error.
 *
 * This will only work usefully if the datatype's input function has been
 * updated to return "soft" errors via errsave/ereturn.
 */
Datum
pg_input_error_info(PG_FUNCTION_ARGS)
{
        text       *txt = PG_GETARG_TEXT_PP(0);
        text       *typname = PG_GETARG_TEXT_PP(1);
        ErrorSaveContext escontext = {T_ErrorSaveContext};
        TupleDesc       tupdesc;
        Datum           values[4];
        bool            isnull[4];

        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
                elog(ERROR, "return type must be a row type");

        /* Enable details_wanted */
        escontext.details_wanted = true;

        if (pg_input_is_valid_common(fcinfo, txt, typname,
                                                                 &escontext))
                memset(isnull, true, sizeof(isnull));
        else
        {
                char       *sqlstate;

                Assert(escontext.error_occurred);
                Assert(escontext.error_data != NULL);
                Assert(escontext.error_data->message != NULL);

                memset(isnull, false, sizeof(isnull));

                values[0] = CStringGetTextDatum(escontext.error_data->message);

                if (escontext.error_data->detail != NULL)
                        values[1] = CStringGetTextDatum(escontext.error_data->detail);
                else
                        isnull[1] = true;

                if (escontext.error_data->hint != NULL)
                        values[2] = CStringGetTextDatum(escontext.error_data->hint);
                else
                        isnull[2] = true;

                sqlstate = unpack_sql_state(escontext.error_data->sqlerrcode);
                values[3] = CStringGetTextDatum(sqlstate);
        }

        return HeapTupleGetDatum(heap_form_tuple(tupdesc, values, isnull));
}

/* Common subroutine for the above */
static bool
pg_input_is_valid_common(FunctionCallInfo fcinfo,
                                                 text *txt, text *typname,
                                                 ErrorSaveContext *escontext)
{
        char       *str = text_to_cstring(txt);
        ValidIOData *my_extra;
        Datum           converted;

        /*
         * We arrange to look up the needed I/O info just once per series of
         * calls, assuming the data type doesn't change underneath us.
         */
        my_extra = (ValidIOData *) fcinfo->flinfo->fn_extra;
        if (my_extra == NULL)
        {
                fcinfo->flinfo->fn_extra =
                        MemoryContextAlloc(fcinfo->flinfo->fn_mcxt,
                                                           sizeof(ValidIOData));
                my_extra = (ValidIOData *) fcinfo->flinfo->fn_extra;
                my_extra->typoid = InvalidOid;
                /* Detect whether typname argument is constant. */
                my_extra->typname_constant = get_fn_expr_arg_stable(fcinfo->flinfo, 1);
        }

        /*
         * If the typname argument is constant, we only need to parse it the first
         * time through.
         */
        if (my_extra->typoid == InvalidOid || !my_extra->typname_constant)
        {
                char       *typnamestr = text_to_cstring(typname);
                Oid                     typoid;

                /* Parse type-name argument to obtain type OID and encoded typmod. */
                (void) parseTypeString(typnamestr, &typoid, &my_extra->typmod, NULL);

                /* Update type-specific info if typoid changed. */
                if (my_extra->typoid != typoid)
                {
                        getTypeInputInfo(typoid,
                                                         &my_extra->typiofunc,
                                                         &my_extra->typioparam);
                        fmgr_info_cxt(my_extra->typiofunc, &my_extra->inputproc,
                                                  fcinfo->flinfo->fn_mcxt);
                        my_extra->typoid = typoid;
                }
        }

        /* Now we can try to perform the conversion. */
        return InputFunctionCallSafe(&my_extra->inputproc,
                                                                 str,
                                                                 my_extra->typioparam,
                                                                 my_extra->typmod,
                                                                 (Node *) escontext,
                                                                 &converted);
}


/*
 * Is character a valid identifier start?
 * Must match scan.l's {ident_start} character class.
 */
static bool
is_ident_start(unsigned char c)
{
        /* Underscores and ASCII letters are OK */
        if (c == '_')
                return true;
        if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
                return true;
        /* Any high-bit-set character is OK (might be part of a multibyte char) */
        if (IS_HIGHBIT_SET(c))
                return true;
        return false;
}

/*
 * Is character a valid identifier continuation?
 * Must match scan.l's {ident_cont} character class.
 */
static bool
is_ident_cont(unsigned char c)
{
        /* Can be digit or dollar sign ... */
        if ((c >= '0' && c <= '9') || c == '$')
                return true;
        /* ... or an identifier start character */
        return is_ident_start(c);
}

/*
 * parse_ident - parse a SQL qualified identifier into separate identifiers.
 * When strict mode is active (second parameter), then any chars after
 * the last identifier are disallowed.
 */
Datum
parse_ident(PG_FUNCTION_ARGS)
{
        text       *qualname = PG_GETARG_TEXT_PP(0);
        bool            strict = PG_GETARG_BOOL(1);
        char       *qualname_str = text_to_cstring(qualname);
        ArrayBuildState *astate = NULL;
        char       *nextp;
        bool            after_dot = false;

        /*
         * The code below scribbles on qualname_str in some cases, so we should
         * reconvert qualname if we need to show the original string in error
         * messages.
         */
        nextp = qualname_str;

        /* skip leading whitespace */
        while (scanner_isspace(*nextp))
                nextp++;

        for (;;)
        {
                char       *curname;
                bool            missing_ident = true;

                if (*nextp == '"')
                {
                        char       *endp;

                        curname = nextp + 1;
                        for (;;)
                        {
                                endp = strchr(nextp + 1, '"');
                                if (endp == NULL)
                                        ereport(ERROR,
                                                        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                         errmsg("string is not a valid identifier: \"%s\"",
                                                                        text_to_cstring(qualname)),
                                                         errdetail("String has unclosed double quotes.")));
                                if (endp[1] != '"')
                                        break;
                                memmove(endp, endp + 1, strlen(endp));
                                nextp = endp;
                        }
                        nextp = endp + 1;
                        *endp = '\0';

                        if (endp - curname == 0)
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("string is not a valid identifier: \"%s\"",
                                                                text_to_cstring(qualname)),
                                                 errdetail("Quoted identifier must not be empty.")));

                        astate = accumArrayResult(astate, CStringGetTextDatum(curname),
                                                                          false, TEXTOID, CurrentMemoryContext);
                        missing_ident = false;
                }
                else if (is_ident_start((unsigned char) *nextp))
                {
                        char       *downname;
                        int                     len;
                        text       *part;

                        curname = nextp++;
                        while (is_ident_cont((unsigned char) *nextp))
                                nextp++;

                        len = nextp - curname;

                        /*
                         * We don't implicitly truncate identifiers. This is useful for
                         * allowing the user to check for specific parts of the identifier
                         * being too long. It's easy enough for the user to get the
                         * truncated names by casting our output to name[].
                         */
                        downname = downcase_identifier(curname, len, false, false);
                        part = cstring_to_text_with_len(downname, len);
                        astate = accumArrayResult(astate, PointerGetDatum(part), false,
                                                                          TEXTOID, CurrentMemoryContext);
                        missing_ident = false;
                }

                if (missing_ident)
                {
                        /* Different error messages based on where we failed. */
                        if (*nextp == '.')
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("string is not a valid identifier: \"%s\"",
                                                                text_to_cstring(qualname)),
                                                 errdetail("No valid identifier before \".\".")));
                        else if (after_dot)
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("string is not a valid identifier: \"%s\"",
                                                                text_to_cstring(qualname)),
                                                 errdetail("No valid identifier after \".\".")));
                        else
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("string is not a valid identifier: \"%s\"",
                                                                text_to_cstring(qualname))));
                }

                while (scanner_isspace(*nextp))
                        nextp++;

                if (*nextp == '.')
                {
                        after_dot = true;
                        nextp++;
                        while (scanner_isspace(*nextp))
                                nextp++;
                }
                else if (*nextp == '\0')
                {
                        break;
                }
                else
                {
                        if (strict)
                                ereport(ERROR,
                                                (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                                 errmsg("string is not a valid identifier: \"%s\"",
                                                                text_to_cstring(qualname))));
                        break;
                }
        }

        PG_RETURN_DATUM(makeArrayResult(astate, CurrentMemoryContext));
}

/*
 * pg_current_logfile
 *
 * Report current log file used by log collector by scanning current_logfiles.
 */
Datum
pg_current_logfile(PG_FUNCTION_ARGS)
{
        FILE       *fd;
        char            lbuffer[MAXPGPATH];
        char       *logfmt;

        /* The log format parameter is optional */
        if (PG_NARGS() == 0 || PG_ARGISNULL(0))
                logfmt = NULL;
        else
        {
                logfmt = text_to_cstring(PG_GETARG_TEXT_PP(0));

                if (strcmp(logfmt, "stderr") != 0 &&
                        strcmp(logfmt, "csvlog") != 0 &&
                        strcmp(logfmt, "jsonlog") != 0)
                        ereport(ERROR,
                                        (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                                         errmsg("log format \"%s\" is not supported", logfmt),
                                         errhint("The supported log formats are \"stderr\", \"csvlog\", and \"jsonlog\".")));
        }

        fd = AllocateFile(LOG_METAINFO_DATAFILE, "r");
        if (fd == NULL)
        {
                if (errno != ENOENT)
                        ereport(ERROR,
                                        (errcode_for_file_access(),
                                         errmsg("could not read file \"%s\": %m",
                                                        LOG_METAINFO_DATAFILE)));
                PG_RETURN_NULL();
        }

#ifdef WIN32
        /* syslogger.c writes CRLF line endings on Windows */
        _setmode(_fileno(fd), _O_TEXT);
#endif

        /*
         * Read the file to gather current log filename(s) registered by the
         * syslogger.
         */
        while (fgets(lbuffer, sizeof(lbuffer), fd) != NULL)
        {
                char       *log_format;
                char       *log_filepath;
                char       *nlpos;

                /* Extract log format and log file path from the line. */
                log_format = lbuffer;
                log_filepath = strchr(lbuffer, ' ');
                if (log_filepath == NULL)
                {
                        /* Uh oh.  No space found, so file content is corrupted. */
                        elog(ERROR,
                                 "missing space character in \"%s\"", LOG_METAINFO_DATAFILE);
                        break;
                }

                *log_filepath = '\0';
                log_filepath++;
                nlpos = strchr(log_filepath, '\n');
                if (nlpos == NULL)
                {
                        /* Uh oh.  No newline found, so file content is corrupted. */
                        elog(ERROR,
                                 "missing newline character in \"%s\"", LOG_METAINFO_DATAFILE);
                        break;
                }
                *nlpos = '\0';

                if (logfmt == NULL || strcmp(logfmt, log_format) == 0)
                {
                        FreeFile(fd);
                        PG_RETURN_TEXT_P(cstring_to_text(log_filepath));
                }
        }

        /* Close the current log filename file. */
        FreeFile(fd);

        PG_RETURN_NULL();
}

/*
 * Report current log file used by log collector (1 argument version)
 *
 * note: this wrapper is necessary to pass the sanity check in opr_sanity,
 * which checks that all built-in functions that share the implementing C
 * function take the same number of arguments
 */
Datum
pg_current_logfile_1arg(PG_FUNCTION_ARGS)
{
        return pg_current_logfile(fcinfo);
}

/*
 * SQL wrapper around RelationGetReplicaIndex().
 */
Datum
pg_get_replica_identity_index(PG_FUNCTION_ARGS)
{
        Oid                     reloid = PG_GETARG_OID(0);
        Oid                     idxoid;
        Relation        rel;

        rel = table_open(reloid, AccessShareLock);
        idxoid = RelationGetReplicaIndex(rel);
        table_close(rel, AccessShareLock);

        if (OidIsValid(idxoid))
                PG_RETURN_OID(idxoid);
        else
                PG_RETURN_NULL();
}

/*
 * Transition function for the ANY_VALUE aggregate
 */
Datum
any_value_transfn(PG_FUNCTION_ARGS)
{
        PG_RETURN_DATUM(PG_GETARG_DATUM(0));
}