/*-------------------------------------------------------------------------
 *
 * parse_type.c
 *		handle type operations for parser
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/parser/parse_type.c,v 1.40 2002/04/20 21:56:14 petere Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "catalog/namespace.h"
#include "catalog/pg_type.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/parsenodes.h"
#include "parser/parser.h"
#include "parser/parse_expr.h"
#include "parser/parse_type.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"


/*
 * LookupTypeName
 *		Given a TypeName object, get the OID of the referenced type.
 *		Returns InvalidOid if no such type can be found.
 *
 * NB: even if the returned OID is not InvalidOid, the type might be
 * just a shell.  Caller should check typisdefined before using the type.
 */
Oid
LookupTypeName(const TypeName *typename)
{
	Oid			restype;

	/* Easy if it's an internally generated TypeName */
	if (typename->names == NIL)
		return typename->typeid;

	if (typename->pct_type)
	{
		/* Handle %TYPE reference to type of an existing field */
		RangeVar   *rel = makeRangeVar(NULL, NULL);
		char	   *field = NULL;
		Oid			relid;
		AttrNumber	attnum;

		/* deconstruct the name list */
		switch (length(typename->names))
		{
			case 1:
				elog(ERROR, "Improper %%TYPE reference (too few dotted names)");
				break;
			case 2:
				rel->relname = strVal(lfirst(typename->names));
				field = strVal(lsecond(typename->names));
				break;
			case 3:
				rel->schemaname = strVal(lfirst(typename->names));
				rel->relname = strVal(lsecond(typename->names));
				field = strVal(lfirst(lnext(lnext(typename->names))));
				break;
			case 4:
				rel->catalogname = strVal(lfirst(typename->names));
				rel->schemaname = strVal(lsecond(typename->names));
				rel->relname = strVal(lfirst(lnext(lnext(typename->names))));
				field = strVal(lfirst(lnext(lnext(lnext(typename->names)))));
				break;
			default:
				elog(ERROR, "Improper %%TYPE reference (too many dotted names)");
				break;
		}

		/* look up the field */
		relid = RangeVarGetRelid(rel, false);
		attnum = get_attnum(relid, field);
		if (attnum == InvalidAttrNumber)
			elog(ERROR, "'%s' is not an attribute of class '%s'",
				 field, rel->relname);
		restype = get_atttype(relid, attnum);

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

		/* emit nuisance warning */
		elog(NOTICE, "%s converted to %s",
			 TypeNameToString(typename), typeidTypeName(restype));
	}
	else
	{
		/* Normal reference to a type name */
		char	   *catalogname;
		char	   *schemaname = NULL;
		char	   *typname = NULL;

		/* deconstruct the name list */
		switch (length(typename->names))
		{
			case 1:
				typname = strVal(lfirst(typename->names));
				break;
			case 2:
				schemaname = strVal(lfirst(typename->names));
				typname = strVal(lsecond(typename->names));
				break;
			case 3:
				catalogname = strVal(lfirst(typename->names));
				schemaname = strVal(lsecond(typename->names));
				typname = strVal(lfirst(lnext(lnext(typename->names))));
				/*
				 * We check the catalog name and then ignore it.
				 */
				if (strcmp(catalogname, DatabaseName) != 0)
					elog(ERROR, "Cross-database references are not implemented");
				break;
			default:
				elog(ERROR, "Improper type name (too many dotted names)");
				break;
		}

		/* If an array reference, look up the array type instead */
		if (typename->arrayBounds != NIL)
			typname = makeArrayTypeName(typname);

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

			namespaceId = GetSysCacheOid(NAMESPACENAME,
										 CStringGetDatum(schemaname),
										 0, 0, 0);
			if (!OidIsValid(namespaceId))
				elog(ERROR, "Namespace \"%s\" does not exist",
					 schemaname);
			restype = GetSysCacheOid(TYPENAMENSP,
									 PointerGetDatum(typname),
									 ObjectIdGetDatum(namespaceId),
									 0, 0);
		}
		else
		{
			/* Unqualified type name, so search the search path */
			restype = TypenameGetTypid(typname);
		}
	}

	return restype;
}

/*
 * 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);

	if (typename->names != NIL)
	{
		/* Emit possibly-qualified name as-is */
		List		*l;

		foreach(l, typename->names)
		{
			if (l != typename->names)
				appendStringInfoChar(&string, '.');
			appendStringInfo(&string, "%s", strVal(lfirst(l)));
		}
	}
	else
	{
		/* Look up internally-specified type */
		appendStringInfo(&string, "%s", typeidTypeName(typename->typeid));
	}

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

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

	return string.data;
}

/*
 * typenameTypeId - given a TypeName, return the type's OID
 *
 * This is equivalent to LookupTypeName, except that this will report
 * a suitable error message if the type cannot be found or is not defined.
 */
Oid
typenameTypeId(const TypeName *typename)
{
	Oid			typoid;

	typoid = LookupTypeName(typename);
	if (!OidIsValid(typoid))
		elog(ERROR, "Type \"%s\" does not exist",
			 TypeNameToString(typename));
	if (!get_typisdefined(typoid))
		elog(ERROR, "Type \"%s\" is only a shell",
			 TypeNameToString(typename));
	return typoid;
}

/*
 * typenameType - given a TypeName, return a Type structure
 *
 * This is equivalent to typenameTypeId + syscache fetch of Type tuple.
 * NB: caller must ReleaseSysCache the type tuple when done with it.
 */
Type
typenameType(const TypeName *typename)
{
	Oid			typoid;
	HeapTuple	tup;

	typoid = LookupTypeName(typename);
	if (!OidIsValid(typoid))
		elog(ERROR, "Type \"%s\" does not exist",
			 TypeNameToString(typename));
	tup = SearchSysCache(TYPEOID,
						 ObjectIdGetDatum(typoid),
						 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "Type \"%s\" does not exist",
			 TypeNameToString(typename));
	if (! ((Form_pg_type) GETSTRUCT(tup))->typisdefined)
		elog(ERROR, "Type \"%s\" is only a shell",
			 TypeNameToString(typename));
	return (Type) tup;
}

/* check to see if a type id is valid,
 * returns true if it is. By using this call before calling
 * typeidType or typeidTypeName, more meaningful error messages
 * can be produced because the caller typically has more context of
 *	what's going on                 - jolly
 */
bool
typeidIsValid(Oid id)
{
	return SearchSysCacheExists(TYPEOID,
								ObjectIdGetDatum(id),
								0, 0, 0);
}

/* 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, "Unable to locate type oid %u in catalog", id);
	return (Type) tup;
}

/* given type (as type struct), return the type OID */
Oid
typeTypeId(Type tp)
{
	if (tp == NULL)
		elog(ERROR, "typeTypeId() called with NULL type struct");
	return tp->t_data->t_oid;
}

/* 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));
}

/* given a type, return its typetype ('c' for 'c'atalog types) */
char
typeTypeFlag(Type t)
{
	Form_pg_type typ;

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

Oid
typeTypeRelid(Type typ)
{
	Form_pg_type typtup;

	typtup = (Form_pg_type) GETSTRUCT(typ);

	return typtup->typrelid;
}

#ifdef NOT_USED
Oid
typeTypElem(Type typ)
{
	Form_pg_type typtup;

	typtup = (Form_pg_type) GETSTRUCT(typ);

	return typtup->typelem;
}
#endif

#ifdef NOT_USED
/* Given a type structure, return the in-conversion function of the type */
Oid
typeInfunc(Type typ)
{
	Form_pg_type typtup;

	typtup = (Form_pg_type) GETSTRUCT(typ);

	return typtup->typinput;
}
#endif

#ifdef NOT_USED
/* Given a type structure, return the out-conversion function of the type */
Oid
typeOutfunc(Type typ)
{
	Form_pg_type typtup;

	typtup = (Form_pg_type) GETSTRUCT(typ);

	return typtup->typoutput;
}
#endif

/* Given a type structure and a string, returns the internal form of
   that string */
Datum
stringTypeDatum(Type tp, char *string, int32 atttypmod)
{
	Oid			op;
	Oid			typelem;

	op = ((Form_pg_type) GETSTRUCT(tp))->typinput;
	typelem = ((Form_pg_type) GETSTRUCT(tp))->typelem;	/* XXX - used for
														 * array_in */
	return OidFunctionCall3(op,
							CStringGetDatum(string),
							ObjectIdGetDatum(typelem),
							Int32GetDatum(atttypmod));
}

/* Given a type id, returns the out-conversion function of the type */
#ifdef NOT_USED
Oid
typeidOutfunc(Oid type_id)
{
	HeapTuple	typeTuple;
	Form_pg_type type;
	Oid			outfunc;

	typeTuple = SearchSysCache(TYPEOID,
							   ObjectIdGetDatum(type_id),
							   0, 0, 0);
	if (!HeapTupleIsValid(typeTuple))
		elog(ERROR, "typeidOutfunc: Invalid type - oid = %u", type_id);

	type = (Form_pg_type) GETSTRUCT(typeTuple);
	outfunc = type->typoutput;
	ReleaseSysCache(typeTuple);
	return outfunc;
}
#endif

/* return a type name, given a typeid */
/* nb: type name is NOT unique; use this only for error messages */
char *
typeidTypeName(Oid id)
{
	HeapTuple	tup;
	Form_pg_type typetuple;
	char	   *result;

	tup = SearchSysCache(TYPEOID,
						 ObjectIdGetDatum(id),
						 0, 0, 0);
	if (!HeapTupleIsValid(tup))
		elog(ERROR, "Unable to locate type oid %u in catalog", id);
	typetuple = (Form_pg_type) GETSTRUCT(tup);

	/*
	 * pstrdup here because result may need to outlive the syscache entry
	 * (eg, it might end up as part of a parse tree that will outlive the
	 * current transaction...)
	 */
	result = pstrdup(NameStr(typetuple->typname));
	ReleaseSysCache(tup);
	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, "typeidTypeRelid: Invalid type - oid = %u", type_id);

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

/*
 * 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.
 *
 * This routine is not currently used by the main backend, but it is
 * exported for use by add-on modules such as plpgsql, in hopes of
 * centralizing parsing knowledge about SQL type declarations.
 */
void
parseTypeString(const char *str, Oid *type_id, int32 *typmod)
{
	StringInfoData buf;
	List	   *raw_parsetree_list;
	SelectStmt *stmt;
	ResTarget  *restarget;
	A_Const    *aconst;
	TypeName   *typename;

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

	raw_parsetree_list = parser(&buf, NULL, 0);

	/*
	 * Make sure we got back exactly what we expected and no more;
	 * paranoia is justified since the string might contain anything.
	 */
	if (length(raw_parsetree_list) != 1)
		elog(ERROR, "Invalid type name '%s'", str);
	stmt = (SelectStmt *) lfirst(raw_parsetree_list);
	if (stmt == NULL ||
		!IsA(stmt, SelectStmt) ||
		stmt->distinctClause != NIL ||
		stmt->into != NULL ||
		stmt->fromClause != NIL ||
		stmt->whereClause != NULL ||
		stmt->groupClause != NIL ||
		stmt->havingClause != NULL ||
		stmt->sortClause != NIL ||
		stmt->portalname != NULL ||
		stmt->limitOffset != NULL ||
		stmt->limitCount != NULL ||
		stmt->forUpdate != NIL ||
		stmt->op != SETOP_NONE)
		elog(ERROR, "Invalid type name '%s'", str);
	if (length(stmt->targetList) != 1)
		elog(ERROR, "Invalid type name '%s'", str);
	restarget = (ResTarget *) lfirst(stmt->targetList);
	if (restarget == NULL ||
		!IsA(restarget, ResTarget) ||
		restarget->name != NULL ||
		restarget->indirection != NIL)
		elog(ERROR, "Invalid type name '%s'", str);
	aconst = (A_Const *) restarget->val;
	if (aconst == NULL ||
		!IsA(aconst, A_Const) ||
		aconst->val.type != T_Null)
		elog(ERROR, "Invalid type name '%s'", str);
	typename = aconst->typename;
	if (typename == NULL ||
		!IsA(typename, TypeName))
		elog(ERROR, "Invalid type name '%s'", str);

	*type_id = typenameTypeId(typename);
	*typmod = typename->typmod;

	pfree(buf.data);
}
