Fix xslt_process() to ensure that it inserts a NULL terminator after the

[PostgreSQL.git] / src / backend / parser / parse_type.c

/*-------------------------------------------------------------------------
 *
 * parse_type.c
 *              handle type operations for parser
 *
 * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *        $PostgreSQL$
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "lib/stringinfo.h"
#include "nodes/makefuncs.h"
#include "parser/parser.h"
#include "parser/parse_type.h"
#include "utils/array.h"
#include "utils/builtins.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"


static int32 typenameTypeMod(ParseState *pstate, const TypeName *typename,
                                Type typ);


/*
 * LookupTypeName
 *              Given a TypeName object, lookup the pg_type syscache entry of the type.
 *              Returns NULL if no such type can be found.      If the type is found,
 *              the typmod value represented in the TypeName struct is computed and
 *              stored into *typmod_p.
 *
 * NB: on success, the caller must ReleaseSysCache the type tuple when done
 * with it.
 *
 * NB: direct callers of this function MUST check typisdefined before assuming
 * that the type is fully valid.  Most code should go through typenameType
 * or typenameTypeId instead.
 *
 * typmod_p can be passed as NULL if the caller does not care to know the
 * typmod value, but the typmod decoration (if any) will be validated anyway,
 * except in the case where the type is not found.      Note that if the type is
 * found but is a shell, and there is typmod decoration, an error will be
 * thrown --- this is intentional.
 *
 * pstate is only used for error location info, and may be NULL.
 */
Type
LookupTypeName(ParseState *pstate, const TypeName *typename,
                           int32 *typmod_p)
{
        Oid                     typoid;
        HeapTuple       tup;
        int32           typmod;

        if (typename->names == NIL)
        {
                /* We have the OID already if it's an internally generated TypeName */
                typoid = typename->typeid;
        }
        else if (typename->pct_type)
        {
                /* Handle %TYPE reference to type of an existing field */
                RangeVar   *rel = makeRangeVar(NULL, NULL, typename->location);
                char       *field = NULL;
                Oid                     relid;
                AttrNumber      attnum;

                /* deconstruct the name list */
                switch (list_length(typename->names))
                {
                        case 1:
                                ereport(ERROR,
                                                (errcode(ERRCODE_SYNTAX_ERROR),
                                errmsg("improper %%TYPE reference (too few dotted names): %s",
                                           NameListToString(typename->names)),
                                                 parser_errposition(pstate, typename->location)));
                                break;
                        case 2:
                                rel->relname = strVal(linitial(typename->names));
                                field = strVal(lsecond(typename->names));
                                break;
                        case 3:
                                rel->schemaname = strVal(linitial(typename->names));
                                rel->relname = strVal(lsecond(typename->names));
                                field = strVal(lthird(typename->names));
                                break;
                        case 4:
                                rel->catalogname = strVal(linitial(typename->names));
                                rel->schemaname = strVal(lsecond(typename->names));
                                rel->relname = strVal(lthird(typename->names));
                                field = strVal(lfourth(typename->names));
                                break;
                        default:
                                ereport(ERROR,
                                                (errcode(ERRCODE_SYNTAX_ERROR),
                                                 errmsg("improper %%TYPE reference (too many dotted names): %s",
                                                                NameListToString(typename->names)),
                                                 parser_errposition(pstate, typename->location)));
                                break;
                }

                /* look up the field */
                relid = RangeVarGetRelid(rel, false);
                attnum = get_attnum(relid, field);
                if (attnum == InvalidAttrNumber)
                        ereport(ERROR,
                                        (errcode(ERRCODE_UNDEFINED_COLUMN),
                                         errmsg("column \"%s\" of relation \"%s\" does not exist",
                                                        field, rel->relname),
                                         parser_errposition(pstate, typename->location)));
                typoid = get_atttype(relid, attnum);

                /* this construct should never have an array indicator */
                Assert(typename->arrayBounds == NIL);

                /* emit nuisance notice (intentionally not errposition'd) */
                ereport(NOTICE,
                                (errmsg("type reference %s converted to %s",
                                                TypeNameToString(typename),
                                                format_type_be(typoid))));
        }
        else
        {
                /* Normal reference to a type name */
                char       *schemaname;
                char       *typname;

                /* deconstruct the name list */
                DeconstructQualifiedName(typename->names, &schemaname, &typname);

                if (schemaname)
                {
                        /* Look in specific schema only */
                        Oid                     namespaceId;

                        namespaceId = LookupExplicitNamespace(schemaname);
                        typoid = GetSysCacheOid(TYPENAMENSP,
                                                                        PointerGetDatum(typname),
                                                                        ObjectIdGetDatum(namespaceId),
                                                                        0, 0);
                }
                else
                {
                        /* Unqualified type name, so search the search path */
                        typoid = TypenameGetTypid(typname);
                }

                /* If an array reference, return the array type instead */
                if (typename->arrayBounds != NIL)
                        typoid = get_array_type(typoid);
        }

        if (!OidIsValid(typoid))
        {
                if (typmod_p)
                        *typmod_p = -1;
                return NULL;
        }

        tup = SearchSysCache(TYPEOID,
                                                 ObjectIdGetDatum(typoid),
                                                 0, 0, 0);
        if (!HeapTupleIsValid(tup)) /* should not happen */
                elog(ERROR, "cache lookup failed for type %u", typoid);

        typmod = typenameTypeMod(pstate, typename, (Type) tup);

        if (typmod_p)
                *typmod_p = typmod;

        return (Type) tup;
}

/*
 * typenameType - given a TypeName, return a Type structure and typmod
 *
 * This is equivalent to LookupTypeName, except that this will report
 * a suitable error message if the type cannot be found or is not defined.
 * Callers of this can therefore assume the result is a fully valid type.
 */
Type
typenameType(ParseState *pstate, const TypeName *typename, int32 *typmod_p)
{
        Type            tup;

        tup = LookupTypeName(pstate, typename, typmod_p);
        if (tup == NULL)
                ereport(ERROR,
                                (errcode(ERRCODE_UNDEFINED_OBJECT),
                                 errmsg("type \"%s\" does not exist",
                                                TypeNameToString(typename)),
                                 parser_errposition(pstate, typename->location)));
        if (!((Form_pg_type) GETSTRUCT(tup))->typisdefined)
                ereport(ERROR,
                                (errcode(ERRCODE_UNDEFINED_OBJECT),
                                 errmsg("type \"%s\" is only a shell",
                                                TypeNameToString(typename)),
                                 parser_errposition(pstate, typename->location)));
        return tup;
}

/*
 * typenameTypeId - given a TypeName, return the type's OID and typmod
 *
 * This is equivalent to typenameType, but we only hand back the type OID
 * not the syscache entry.
 */
Oid
typenameTypeId(ParseState *pstate, const TypeName *typename, int32 *typmod_p)
{
        Oid                     typoid;
        Type            tup;

        tup = typenameType(pstate, typename, typmod_p);
        typoid = HeapTupleGetOid(tup);
        ReleaseSysCache(tup);

        return typoid;
}

/*
 * typenameTypeMod - given a TypeName, return the internal typmod value
 *
 * This will throw an error if the TypeName includes type modifiers that are
 * illegal for the data type.
 *
 * The actual type OID represented by the TypeName must already have been
 * looked up, and is passed as "typ".
 *
 * pstate is only used for error location info, and may be NULL.
 */
static int32
typenameTypeMod(ParseState *pstate, const TypeName *typename, Type typ)
{
        int32           result;
        Oid                     typmodin;
        Datum      *datums;
        int                     n;
        ListCell   *l;
        ArrayType  *arrtypmod;
        ParseCallbackState pcbstate;

        /* Return prespecified typmod if no typmod expressions */
        if (typename->typmods == NIL)
                return typename->typemod;

        /*
         * Else, type had better accept typmods.  We give a special error message
         * for the shell-type case, since a shell couldn't possibly have a
         * typmodin function.
         */
        if (!((Form_pg_type) GETSTRUCT(typ))->typisdefined)
                ereport(ERROR,
                                (errcode(ERRCODE_SYNTAX_ERROR),
                        errmsg("type modifier cannot be specified for shell type \"%s\"",
                                   TypeNameToString(typename)),
                                 parser_errposition(pstate, typename->location)));

        typmodin = ((Form_pg_type) GETSTRUCT(typ))->typmodin;

        if (typmodin == InvalidOid)
                ereport(ERROR,
                                (errcode(ERRCODE_SYNTAX_ERROR),
                                 errmsg("type modifier is not allowed for type \"%s\"",
                                                TypeNameToString(typename)),
                                 parser_errposition(pstate, typename->location)));

        /*
         * Convert the list of raw-grammar-output expressions to a cstring array.
         * Currently, we allow simple numeric constants, string literals, and
         * identifiers; possibly this list could be extended.
         */
        datums = (Datum *) palloc(list_length(typename->typmods) * sizeof(Datum));
        n = 0;
        foreach(l, typename->typmods)
        {
                Node       *tm = (Node *) lfirst(l);
                char       *cstr = NULL;

                if (IsA(tm, A_Const))
                {
                        A_Const    *ac = (A_Const *) tm;

                        if (IsA(&ac->val, Integer))
                        {
                                cstr = (char *) palloc(32);
                                snprintf(cstr, 32, "%ld", (long) ac->val.val.ival);
                        }
                        else if (IsA(&ac->val, Float) ||
                                         IsA(&ac->val, String))
                        {
                                /* we can just use the str field directly. */
                                cstr = ac->val.val.str;
                        }
                }
                else if (IsA(tm, ColumnRef))
                {
                        ColumnRef  *cr = (ColumnRef *) tm;

                        if (list_length(cr->fields) == 1 &&
                                IsA(linitial(cr->fields), String))
                                cstr = strVal(linitial(cr->fields));
                }
                if (!cstr)
                        ereport(ERROR,
                                        (errcode(ERRCODE_SYNTAX_ERROR),
                        errmsg("type modifiers must be simple constants or identifiers"),
                                         parser_errposition(pstate, typename->location)));
                datums[n++] = CStringGetDatum(cstr);
        }

        /* hardwired knowledge about cstring's representation details here */
        arrtypmod = construct_array(datums, n, CSTRINGOID,
                                                                -2, false, 'c');

        /* arrange to report location if type's typmodin function fails */
        setup_parser_errposition_callback(&pcbstate, pstate, typename->location);

        result = DatumGetInt32(OidFunctionCall1(typmodin,
                                                                                        PointerGetDatum(arrtypmod)));

        cancel_parser_errposition_callback(&pcbstate);

        pfree(datums);
        pfree(arrtypmod);

        return result;
}

/*
 * appendTypeNameToBuffer
 *              Append a string representing the name of a TypeName to a StringInfo.
 *              This is the shared guts of TypeNameToString and TypeNameListToString.
 *
 * NB: this must work on TypeNames that do not describe any actual type;
 * it is mostly used for reporting lookup errors.
 */
static void
appendTypeNameToBuffer(const TypeName *typename, StringInfo string)
{
        if (typename->names != NIL)
        {
                /* Emit possibly-qualified name as-is */
                ListCell   *l;

                foreach(l, typename->names)
                {
                        if (l != list_head(typename->names))
                                appendStringInfoChar(string, '.');
                        appendStringInfoString(string, strVal(lfirst(l)));
                }
        }
        else
        {
                /* Look up internally-specified type */
                appendStringInfoString(string, format_type_be(typename->typeid));
        }

        /*
         * Add decoration as needed, but only for fields considered by
         * LookupTypeName
         */
        if (typename->pct_type)
                appendStringInfoString(string, "%TYPE");

        if (typename->arrayBounds != NIL)
                appendStringInfoString(string, "[]");
}

/*
 * TypeNameToString
 *              Produce a string representing the name of a TypeName.
 *
 * NB: this must work on TypeNames that do not describe any actual type;
 * it is mostly used for reporting lookup errors.
 */
char *
TypeNameToString(const TypeName *typename)
{
        StringInfoData string;

        initStringInfo(&string);
        appendTypeNameToBuffer(typename, &string);
        return string.data;
}

/*
 * TypeNameListToString
 *              Produce a string representing the name(s) of a List of TypeNames
 */
char *
TypeNameListToString(List *typenames)
{
        StringInfoData string;
        ListCell   *l;

        initStringInfo(&string);
        foreach(l, typenames)
        {
                TypeName   *typename = (TypeName *) lfirst(l);

                Assert(IsA(typename, TypeName));
                if (l != list_head(typenames))
                        appendStringInfoChar(&string, ',');
                appendTypeNameToBuffer(typename, &string);
        }
        return string.data;
}

/* return a Type structure, given a type id */
/* NB: caller must ReleaseSysCache the type tuple when done with it */
Type
typeidType(Oid id)
{
        HeapTuple       tup;

        tup = SearchSysCache(TYPEOID,
                                                 ObjectIdGetDatum(id),
                                                 0, 0, 0);
        if (!HeapTupleIsValid(tup))
                elog(ERROR, "cache lookup failed for type %u", id);
        return (Type) tup;
}

/* given type (as type struct), return the type OID */
Oid
typeTypeId(Type tp)
{
        if (tp == NULL)                         /* probably useless */
                elog(ERROR, "typeTypeId() called with NULL type struct");
        return HeapTupleGetOid(tp);
}

/* given type (as type struct), return the length of type */
int16
typeLen(Type t)
{
        Form_pg_type typ;

        typ = (Form_pg_type) GETSTRUCT(t);
        return typ->typlen;
}

/* given type (as type struct), return the value of its 'byval' attribute.*/
bool
typeByVal(Type t)
{
        Form_pg_type typ;

        typ = (Form_pg_type) GETSTRUCT(t);
        return typ->typbyval;
}

/* given type (as type struct), return the name of type */
char *
typeTypeName(Type t)
{
        Form_pg_type typ;

        typ = (Form_pg_type) GETSTRUCT(t);
        /* pstrdup here because result may need to outlive the syscache entry */
        return pstrdup(NameStr(typ->typname));
}

Oid
typeTypeRelid(Type typ)
{
        Form_pg_type typtup;

        typtup = (Form_pg_type) GETSTRUCT(typ);

        return typtup->typrelid;
}

/*
 * Given a type structure and a string, returns the internal representation
 * of that string.      The "string" can be NULL to perform conversion of a NULL
 * (which might result in failure, if the input function rejects NULLs).
 */
Datum
stringTypeDatum(Type tp, char *string, int32 atttypmod)
{
        Form_pg_type typform = (Form_pg_type) GETSTRUCT(tp);
        Oid                     typinput = typform->typinput;
        Oid                     typioparam = getTypeIOParam(tp);
        Datum           result;

        result = OidInputFunctionCall(typinput, string,
                                                                  typioparam, atttypmod);

#ifdef RANDOMIZE_ALLOCATED_MEMORY

        /*
         * For pass-by-reference data types, repeat the conversion to see if the
         * input function leaves any uninitialized bytes in the result.  We can
         * only detect that reliably if RANDOMIZE_ALLOCATED_MEMORY is enabled, so
         * we don't bother testing otherwise.  The reason we don't want any
         * instability in the input function is that comparison of Const nodes
         * relies on bytewise comparison of the datums, so if the input function
         * leaves garbage then subexpressions that should be identical may not get
         * recognized as such.  See pgsql-hackers discussion of 2008-04-04.
         */
        if (string && !typform->typbyval)
        {
                Datum           result2;

                result2 = OidInputFunctionCall(typinput, string,
                                                                           typioparam, atttypmod);
                if (!datumIsEqual(result, result2, typform->typbyval, typform->typlen))
                        elog(WARNING, "type %s has unstable input conversion for \"%s\"",
                                 NameStr(typform->typname), string);
        }
#endif

        return result;
}

/* given a typeid, return the type's typrelid (associated relation, if any) */
Oid
typeidTypeRelid(Oid type_id)
{
        HeapTuple       typeTuple;
        Form_pg_type type;
        Oid                     result;

        typeTuple = SearchSysCache(TYPEOID,
                                                           ObjectIdGetDatum(type_id),
                                                           0, 0, 0);
        if (!HeapTupleIsValid(typeTuple))
                elog(ERROR, "cache lookup failed for type %u", type_id);

        type = (Form_pg_type) GETSTRUCT(typeTuple);
        result = type->typrelid;
        ReleaseSysCache(typeTuple);
        return result;
}

/*
 * error context callback for parse failure during parseTypeString()
 */
static void
pts_error_callback(void *arg)
{
        const char *str = (const char *) arg;

        errcontext("invalid type name \"%s\"", str);

        /*
         * Currently we just suppress any syntax error position report, rather
         * than transforming to an "internal query" error.      It's unlikely that a
         * type name is complex enough to need positioning.
         */
        errposition(0);
}

/*
 * Given a string that is supposed to be a SQL-compatible type declaration,
 * such as "int4" or "integer" or "character varying(32)", parse
 * the string and convert it to a type OID and type modifier.
 */
void
parseTypeString(const char *str, Oid *type_id, int32 *typmod_p)
{
        StringInfoData buf;
        List       *raw_parsetree_list;
        SelectStmt *stmt;
        ResTarget  *restarget;
        TypeCast   *typecast;
        TypeName   *typename;
        ErrorContextCallback ptserrcontext;

        /* make sure we give useful error for empty input */
        if (strspn(str, " \t\n\r\f") == strlen(str))
                goto fail;

        initStringInfo(&buf);
        appendStringInfo(&buf, "SELECT NULL::%s", str);

        /*
         * Setup error traceback support in case of ereport() during parse
         */
        ptserrcontext.callback = pts_error_callback;
        ptserrcontext.arg = (void *) str;
        ptserrcontext.previous = error_context_stack;
        error_context_stack = &ptserrcontext;

        raw_parsetree_list = raw_parser(buf.data);

        error_context_stack = ptserrcontext.previous;

        /*
         * Make sure we got back exactly what we expected and no more; paranoia is
         * justified since the string might contain anything.
         */
        if (list_length(raw_parsetree_list) != 1)
                goto fail;
        stmt = (SelectStmt *) linitial(raw_parsetree_list);
        if (stmt == NULL ||
                !IsA(stmt, SelectStmt) ||
                stmt->distinctClause != NIL ||
                stmt->intoClause != NULL ||
                stmt->fromClause != NIL ||
                stmt->whereClause != NULL ||
                stmt->groupClause != NIL ||
                stmt->havingClause != NULL ||
                stmt->windowClause != NIL ||
                stmt->withClause != NULL ||
                stmt->valuesLists != NIL ||
                stmt->sortClause != NIL ||
                stmt->limitOffset != NULL ||
                stmt->limitCount != NULL ||
                stmt->lockingClause != NIL ||
                stmt->op != SETOP_NONE)
                goto fail;
        if (list_length(stmt->targetList) != 1)
                goto fail;
        restarget = (ResTarget *) linitial(stmt->targetList);
        if (restarget == NULL ||
                !IsA(restarget, ResTarget) ||
                restarget->name != NULL ||
                restarget->indirection != NIL)
                goto fail;
        typecast = (TypeCast *) restarget->val;
        if (typecast == NULL ||
                !IsA(typecast, TypeCast) ||
                typecast->arg == NULL ||
                !IsA(typecast->arg, A_Const))
                goto fail;
        typename = typecast->typename;
        if (typename == NULL ||
                !IsA(typename, TypeName))
                goto fail;
        if (typename->setof)
                goto fail;

        *type_id = typenameTypeId(NULL, typename, typmod_p);

        pfree(buf.data);

        return;

fail:
        ereport(ERROR,
                        (errcode(ERRCODE_SYNTAX_ERROR),
                         errmsg("invalid type name \"%s\"", str)));
}