/*-------------------------------------------------------------------------
 *
 * indexing.c--
 *    This file contains routines to support indices defined on system
 *    catalogs.
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    $Header: /cvsroot/pgsql/src/backend/catalog/indexing.c,v 1.11 1997/08/31 09:56:18 vadim Exp $
 *
 *-------------------------------------------------------------------------
 */
#include <string.h>

#include <postgres.h>

#include <utils/builtins.h>
#include <utils/oidcompos.h>
#include <access/heapam.h>
#include <access/genam.h>
#include <storage/bufmgr.h>
#include <nodes/execnodes.h>
#include <catalog/catalog.h>
#include <catalog/catname.h>
#include <catalog/pg_index.h>
#include <catalog/pg_proc.h>
#include <utils/syscache.h>
#include <catalog/indexing.h>
#include <catalog/index.h>
#include <miscadmin.h>

/*
 * Names of indices on the following system catalogs:
 *
 *	pg_attribute
 *	pg_proc
 *	pg_type
 *	pg_naming
 *	pg_class
 *	pg_attrdef
 *	pg_relcheck
 *	pg_trigger
 */

char *Name_pg_attr_indices[Num_pg_attr_indices] = {AttributeNameIndex,
						   AttributeNumIndex,
						   AttributeRelidIndex};
char *Name_pg_proc_indices[Num_pg_proc_indices] = { ProcedureNameIndex,
						    ProcedureOidIndex,
						    ProcedureSrcIndex};
char *Name_pg_type_indices[Num_pg_type_indices] = { TypeNameIndex,
						    TypeOidIndex};
char *Name_pg_class_indices[Num_pg_class_indices]= { ClassNameIndex,
						     ClassOidIndex};
char *Name_pg_attrdef_indices[Num_pg_attrdef_indices]= { AttrDefaultIndex };

char *Name_pg_relcheck_indices[Num_pg_relcheck_indices]= { RelCheckIndex };

char *Name_pg_trigger_indices[Num_pg_trigger_indices]= { TriggerRelidIndex };


static HeapTuple CatalogIndexFetchTuple(Relation heapRelation,
					Relation idesc,
					ScanKey skey);


/*
 * Changes (appends) to catalogs can (and does) happen at various places
 * throughout the code.  We need a generic routine that will open all of
 * the indices defined on a given catalog a return the relation descriptors
 * associated with them.
 */
void
CatalogOpenIndices(int nIndices, char *names[], Relation idescs[])
{
    int i;
    
    for (i=0; i<nIndices; i++)
	{
	    idescs[i] = index_openr(names[i]);
	}
}

/*
 * This is the inverse routine to CatalogOpenIndices()
 */
void
CatalogCloseIndices(int nIndices, Relation *idescs)
{
    int i;
    
    for (i=0; i<nIndices; i++)
	index_close(idescs[i]);
}


/*
 * For the same reasons outlined above CatalogOpenIndices() we need a routine
 * that takes a new catalog tuple and inserts an associated index tuple into 
 * each catalog index.
 */
void
CatalogIndexInsert(Relation *idescs,
		   int nIndices,
		   Relation heapRelation,
		   HeapTuple heapTuple)
{
    HeapTuple pgIndexTup;
    TupleDesc heapDescriptor;
    IndexTupleForm pgIndexP;
    Datum datum;
    int natts;
    AttrNumber *attnumP;
    FuncIndexInfo finfo, *finfoP;
    char nulls[INDEX_MAX_KEYS];
    int i;
    
    heapDescriptor =  RelationGetTupleDescriptor(heapRelation);
    
    for (i=0; i<nIndices; i++) 
	{
	    TupleDesc     indexDescriptor;
	    InsertIndexResult indexRes;
	    
	    indexDescriptor = RelationGetTupleDescriptor(idescs[i]);
	    pgIndexTup = SearchSysCacheTuple(INDEXRELID,
					     Int32GetDatum(idescs[i]->rd_id),
					     0,0,0);
	    Assert(pgIndexTup);
	    pgIndexP = (IndexTupleForm)GETSTRUCT(pgIndexTup);
	    
	    /*
	     * Compute the number of attributes we are indexing upon.
	     * very important - can't assume one if this is a functional
	     * index.
	     */
	    for (attnumP=(&pgIndexP->indkey[0]), natts=0;
		 *attnumP != InvalidAttrNumber;
		 attnumP++, natts++)
		;
	    
	    if (pgIndexP->indproc != InvalidOid)
		{
		    FIgetnArgs(&finfo) = natts;
		    natts = 1;
		    FIgetProcOid(&finfo) = pgIndexP->indproc;
		    *(FIgetname(&finfo)) = '\0';
		    finfoP = &finfo;
		}
	    else
		finfoP = (FuncIndexInfo *)NULL;
	    
	    FormIndexDatum(natts,
			   (AttrNumber *)&pgIndexP->indkey[0],
			   heapTuple,
			   heapDescriptor,
			   InvalidBuffer,
			   &datum,
			   nulls,
			   finfoP);
	    
	    indexRes = index_insert(idescs[i], &datum, nulls, 
				    &(heapTuple->t_ctid), heapRelation);
	    if (indexRes) pfree(indexRes);
	}
}

/*
 * This is needed at initialization when reldescs for some of the crucial
 * system catalogs are created and nailed into the cache.
 */
bool
CatalogHasIndex(char *catName, Oid catId)
{
    Relation    pg_class;
    HeapTuple   htup;
    Form_pg_class pgRelP;
    int i;
    
    Assert(IsSystemRelationName(catName));
    
    /*
     * If we're bootstraping we don't have pg_class (or any indices).
     */
    if (IsBootstrapProcessingMode())
	return false;
    
    if (IsInitProcessingMode()) {
	for (i = 0; IndexedCatalogNames[i] != NULL; i++) {
	    if ( strcmp(IndexedCatalogNames[i], catName) == 0)
		return (true);
	}
	return (false);
    }
    
    pg_class = heap_openr(RelationRelationName);
    htup = ClassOidIndexScan(pg_class, catId);
    heap_close(pg_class);
    
    if (! HeapTupleIsValid(htup)) {
	elog(NOTICE, "CatalogHasIndex: no relation with oid %d", catId);
	return false;
    }
    
    pgRelP = (Form_pg_class)GETSTRUCT(htup);
    return (pgRelP->relhasindex);
}

/*
 *  CatalogIndexFetchTuple() -- Get a tuple that satisfies a scan key
 *				from a catalog relation.
 *
 *	Since the index may contain pointers to dead tuples, we need to
 *	iterate until we find a tuple that's valid and satisfies the scan
 *	key.
 */
static HeapTuple
CatalogIndexFetchTuple(Relation heapRelation,
		       Relation idesc,
		       ScanKey skey)
{
    IndexScanDesc sd;
    RetrieveIndexResult indexRes;
    HeapTuple tuple;
    Buffer buffer;
    
    sd = index_beginscan(idesc, false, 1, skey);
    tuple = (HeapTuple)NULL;
    
    do {
	indexRes = index_getnext(sd, ForwardScanDirection);
	if (indexRes) {
	    ItemPointer iptr;
	    
	    iptr = &indexRes->heap_iptr;
	    tuple = heap_fetch(heapRelation, NowTimeQual, iptr, &buffer);
	    pfree(indexRes);
	} else
	    break;
    } while (!HeapTupleIsValid(tuple));
    
    if (HeapTupleIsValid(tuple)) {
	tuple = heap_copytuple(tuple);
	ReleaseBuffer(buffer);
    }
    
    index_endscan(sd);
    pfree(sd);
    return (tuple);
}

/*
 * The remainder of the file is for individual index scan routines.  Each
 * index should be scanned according to how it was defined during bootstrap
 * (that is, functional or normal) and what arguments the cache lookup
 * requires.  Each routine returns the heap tuple that qualifies.
 */
HeapTuple
AttributeNameIndexScan(Relation heapRelation,
		       Oid relid,
		       char *attname)
{
    Relation idesc;
    ScanKeyData skey;
    OidName keyarg;
    HeapTuple tuple;
    
    keyarg = mkoidname(relid, attname);
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)OidNameEqRegProcedure,
			   (Datum)keyarg);
    
    idesc = index_openr(AttributeNameIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    pfree(keyarg);
    
    return tuple;
}

HeapTuple
AttributeNumIndexScan(Relation heapRelation,
		      Oid relid,
		      AttrNumber attnum)
{
    Relation idesc;
    ScanKeyData skey;
    OidInt2 keyarg;
    HeapTuple tuple;
    
    keyarg = mkoidint2(relid, (uint16)attnum);
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)OidInt2EqRegProcedure,
			   (Datum)keyarg);
    
    idesc = index_openr(AttributeNumIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    pfree(keyarg);
    
    return tuple;
}

HeapTuple
ProcedureOidIndexScan(Relation heapRelation, Oid procId)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)ObjectIdEqualRegProcedure,
			   (Datum)procId);
    
    idesc = index_openr(ProcedureOidIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    
    return tuple;
}



HeapTuple
ProcedureNameIndexScan(Relation heapRelation,
                       char *procName,
                       int nargs,
                       Oid *argTypes)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;         /* tuple being tested */
    HeapTuple return_tuple;  /* The tuple pointer we eventually return */
    IndexScanDesc sd;
    RetrieveIndexResult indexRes;
    Buffer buffer;
    Form_pg_proc pgProcP;
    bool ScanComplete;  
      /* The index scan is complete, i.e. we've scanned everything there
         is to scan. 
         */
    bool FoundMatch;
      /* In scanning pg_proc, we have found a row that meets our search 
         criteria.
         */
    
    ScanKeyEntryInitialize(&skey,
                           (bits16)0x0,
                           (AttrNumber)1,
                           (RegProcedure)NameEqualRegProcedure,
                           (Datum)procName);
    
    idesc = index_openr(ProcedureNameIndex);
    
    sd = index_beginscan(idesc, false, 1, &skey);
    
    /*
     * for now, we do the work usually done by CatalogIndexFetchTuple
     * by hand, so that we can check that the other keys match.  when
     * multi-key indices are added, they will be used here.
     */
    tuple = (HeapTuple) NULL;  /* initial value */
    ScanComplete = false;      /* Scan hasn't begun yet */
    FoundMatch = false;        /* No match yet; haven't even looked. */
    while (!FoundMatch && !ScanComplete) {  
        indexRes = index_getnext(sd, ForwardScanDirection);
        if (indexRes) {
            ItemPointer iptr;
        
            iptr = &indexRes->heap_iptr;
            tuple = heap_fetch(heapRelation, NowTimeQual, iptr, &buffer);
            pfree(indexRes);
            if (HeapTupleIsValid(tuple)) {
                /* Here's a row for a procedure that has the sought procedure
                   name.  To be a match, though, we need it to have the
                   right number and type of arguments too, so we check that
                   now.
                   */
                pgProcP = (Form_pg_proc)GETSTRUCT(tuple);
                if (pgProcP->pronargs == nargs &&
                    oid8eq(&(pgProcP->proargtypes[0]), argTypes)) 
                    FoundMatch = true;
                else ReleaseBuffer(buffer);
            }
        } else ScanComplete = true;
    }

    if (FoundMatch) {
        Assert(HeapTupleIsValid(tuple));
        return_tuple = heap_copytuple(tuple);
        ReleaseBuffer(buffer);
    } else return_tuple = (HeapTuple)NULL;
    
    index_endscan(sd);
    index_close(idesc);
    
    return return_tuple;
}



HeapTuple
ProcedureSrcIndexScan(Relation heapRelation, text *procSrc)
{
    Relation idesc;
    IndexScanDesc sd;
    ScanKeyData skey;
    RetrieveIndexResult indexRes;
    HeapTuple tuple;
    Buffer buffer;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)Anum_pg_proc_prosrc,
		           (RegProcedure)TextEqualRegProcedure,
			   (Datum)procSrc);
    
    idesc = index_openr(ProcedureSrcIndex);
    sd = index_beginscan(idesc, false, 1, &skey);
    
    indexRes = index_getnext(sd, ForwardScanDirection);
    if (indexRes) {
	ItemPointer iptr;
	    
	iptr = &indexRes->heap_iptr;
	tuple = heap_fetch(heapRelation, NowTimeQual, iptr, &buffer);
	pfree(indexRes);
    } else
	tuple = (HeapTuple)NULL;
    
    if (HeapTupleIsValid(tuple)) {
	tuple = heap_copytuple(tuple);
	ReleaseBuffer(buffer);
    }
    
    index_endscan(sd);
    
    return tuple;
}

HeapTuple
TypeOidIndexScan(Relation heapRelation, Oid typeId)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)ObjectIdEqualRegProcedure,
			   (Datum)typeId);
    
    idesc = index_openr(TypeOidIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    
    return tuple;
}

HeapTuple
TypeNameIndexScan(Relation heapRelation, char *typeName)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)NameEqualRegProcedure,
			   (Datum)typeName);
    
    idesc = index_openr(TypeNameIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    
    return tuple;
}

HeapTuple
ClassNameIndexScan(Relation heapRelation, char *relName)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)NameEqualRegProcedure,
			   (Datum)relName);
    
    idesc = index_openr(ClassNameIndex);
    
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    return tuple;
}

HeapTuple
ClassOidIndexScan(Relation heapRelation, Oid relId)
{
    Relation idesc;
    ScanKeyData skey;
    HeapTuple tuple;
    
    ScanKeyEntryInitialize(&skey,
			   (bits16)0x0,
			   (AttrNumber)1,
			   (RegProcedure)ObjectIdEqualRegProcedure,
			   (Datum)relId);
    
    idesc = index_openr(ClassOidIndex);
    tuple = CatalogIndexFetchTuple(heapRelation, idesc, &skey);
    
    index_close(idesc);
    
    return tuple;
}