/*-------------------------------------------------------------------------
 *
 * spgvalidate.c
 *	  Opclass validator for SP-GiST.
 *
 * Portions Copyright (c) 1996-2016, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *			src/backend/access/spgist/spgvalidate.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "access/amvalidate.h"
#include "access/htup_details.h"
#include "access/spgist_private.h"
#include "catalog/pg_amop.h"
#include "catalog/pg_amproc.h"
#include "catalog/pg_opclass.h"
#include "catalog/pg_opfamily.h"
#include "catalog/pg_type.h"
#include "utils/builtins.h"
#include "utils/syscache.h"


/*
 * Validator for an SP-GiST opclass.
 *
 * Some of the checks done here cover the whole opfamily, and therefore are
 * redundant when checking each opclass in a family.  But they don't run long
 * enough to be much of a problem, so we accept the duplication rather than
 * complicate the amvalidate API.
 */
bool
spgvalidate(Oid opclassoid)
{
	bool		result = true;
	HeapTuple	classtup;
	Form_pg_opclass classform;
	Oid			opfamilyoid;
	Oid			opcintype;
	char	   *opclassname;
	HeapTuple	familytup;
	Form_pg_opfamily familyform;
	char	   *opfamilyname;
	CatCList   *proclist,
			   *oprlist;
	List	   *grouplist;
	OpFamilyOpFuncGroup *opclassgroup;
	int			i;
	ListCell   *lc;

	/* Fetch opclass information */
	classtup = SearchSysCache1(CLAOID, ObjectIdGetDatum(opclassoid));
	if (!HeapTupleIsValid(classtup))
		elog(ERROR, "cache lookup failed for operator class %u", opclassoid);
	classform = (Form_pg_opclass) GETSTRUCT(classtup);

	opfamilyoid = classform->opcfamily;
	opcintype = classform->opcintype;
	opclassname = NameStr(classform->opcname);

	/* Fetch opfamily information */
	familytup = SearchSysCache1(OPFAMILYOID, ObjectIdGetDatum(opfamilyoid));
	if (!HeapTupleIsValid(familytup))
		elog(ERROR, "cache lookup failed for operator family %u", opfamilyoid);
	familyform = (Form_pg_opfamily) GETSTRUCT(familytup);

	opfamilyname = NameStr(familyform->opfname);

	/* Fetch all operators and support functions of the opfamily */
	oprlist = SearchSysCacheList1(AMOPSTRATEGY, ObjectIdGetDatum(opfamilyoid));
	proclist = SearchSysCacheList1(AMPROCNUM, ObjectIdGetDatum(opfamilyoid));

	/* Check individual support functions */
	for (i = 0; i < proclist->n_members; i++)
	{
		HeapTuple	proctup = &proclist->members[i]->tuple;
		Form_pg_amproc procform = (Form_pg_amproc) GETSTRUCT(proctup);
		bool		ok;

		/*
		 * All SP-GiST support functions should be registered with matching
		 * left/right types
		 */
		if (procform->amproclefttype != procform->amprocrighttype)
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" contains support procedure %s with cross-type registration",
							opfamilyname,
							format_procedure(procform->amproc))));
			result = false;
		}

		/* Check procedure numbers and function signatures */
		switch (procform->amprocnum)
		{
			case SPGIST_CONFIG_PROC:
			case SPGIST_CHOOSE_PROC:
			case SPGIST_PICKSPLIT_PROC:
			case SPGIST_INNER_CONSISTENT_PROC:
				ok = check_amproc_signature(procform->amproc, VOIDOID, true,
											2, 2, INTERNALOID, INTERNALOID);
				break;
			case SPGIST_LEAF_CONSISTENT_PROC:
				ok = check_amproc_signature(procform->amproc, BOOLOID, true,
											2, 2, INTERNALOID, INTERNALOID);
				break;
			default:
				ereport(INFO,
						(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
						 errmsg("spgist operator family \"%s\" contains function %s with invalid support number %d",
								opfamilyname,
								format_procedure(procform->amproc),
								procform->amprocnum)));
				result = false;
				continue;		/* don't want additional message */
		}

		if (!ok)
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" contains function %s with wrong signature for support number %d",
							opfamilyname,
							format_procedure(procform->amproc),
							procform->amprocnum)));
			result = false;
		}
	}

	/* Check individual operators */
	for (i = 0; i < oprlist->n_members; i++)
	{
		HeapTuple	oprtup = &oprlist->members[i]->tuple;
		Form_pg_amop oprform = (Form_pg_amop) GETSTRUCT(oprtup);

		/* TODO: Check that only allowed strategy numbers exist */
		if (oprform->amopstrategy < 1 || oprform->amopstrategy > 63)
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" contains operator %s with invalid strategy number %d",
							opfamilyname,
							format_operator(oprform->amopopr),
							oprform->amopstrategy)));
			result = false;
		}

		/* spgist doesn't support ORDER BY operators */
		if (oprform->amoppurpose != AMOP_SEARCH ||
			OidIsValid(oprform->amopsortfamily))
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" contains invalid ORDER BY specification for operator %s",
							opfamilyname,
							format_operator(oprform->amopopr))));
			result = false;
		}

		/* Check operator signature --- same for all spgist strategies */
		if (!check_amop_signature(oprform->amopopr, BOOLOID,
								  oprform->amoplefttype,
								  oprform->amoprighttype))
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" contains operator %s with wrong signature",
							opfamilyname,
							format_operator(oprform->amopopr))));
			result = false;
		}
	}

	/* Now check for inconsistent groups of operators/functions */
	grouplist = identify_opfamily_groups(oprlist, proclist);
	opclassgroup = NULL;
	foreach(lc, grouplist)
	{
		OpFamilyOpFuncGroup *thisgroup = (OpFamilyOpFuncGroup *) lfirst(lc);

		/* Remember the group exactly matching the test opclass */
		if (thisgroup->lefttype == opcintype &&
			thisgroup->righttype == opcintype)
			opclassgroup = thisgroup;

		/*
		 * Complain if there are any datatype pairs with functions but no
		 * operators.  This is about the best we can do for now to detect
		 * missing operators.
		 */
		if (thisgroup->operatorset == 0)
		{
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" is missing operator(s) for types %s and %s",
							opfamilyname,
							format_type_be(thisgroup->lefttype),
							format_type_be(thisgroup->righttype))));
			result = false;
		}

		/*
		 * Complain if we're missing functions for any datatype, remembering
		 * that SP-GiST doesn't use cross-type support functions.
		 */
		if (thisgroup->lefttype != thisgroup->righttype)
			continue;

		for (i = 1; i <= SPGISTNProc; i++)
		{
			if ((thisgroup->functionset & (((uint64) 1) << i)) != 0)
				continue;		/* got it */
			ereport(INFO,
					(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
					 errmsg("spgist operator family \"%s\" is missing support function %d for type %s",
							opfamilyname, i,
							format_type_be(thisgroup->lefttype))));
			result = false;
		}
	}

	/* Check that the originally-named opclass is supported */
	/* (if group is there, we already checked it adequately above) */
	if (!opclassgroup)
	{
		ereport(INFO,
				(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
				 errmsg("spgist operator class \"%s\" is missing operator(s)",
						opclassname)));
		result = false;
	}

	ReleaseCatCacheList(proclist);
	ReleaseCatCacheList(oprlist);
	ReleaseSysCache(familytup);
	ReleaseSysCache(classtup);

	return result;
}
