/*--------------------------------------------------------------------------
 * gin.h
 *	  header file for postgres inverted index access method implementation.
 *
 *	Copyright (c) 2006-2009, PostgreSQL Global Development Group
 *
 *	$PostgreSQL: pgsql/src/include/access/gin.h,v 1.34.2.3 2010/08/01 19:16:55 tgl Exp $
 *--------------------------------------------------------------------------
 */
#ifndef GIN_H
#define GIN_H

#include "access/genam.h"
#include "access/itup.h"
#include "access/xlog.h"
#include "fmgr.h"


/*
 * amproc indexes for inverted indexes.
 */
#define GIN_COMPARE_PROC			   1
#define GIN_EXTRACTVALUE_PROC		   2
#define GIN_EXTRACTQUERY_PROC		   3
#define GIN_CONSISTENT_PROC			   4
#define GIN_COMPARE_PARTIAL_PROC	   5
#define GINNProcs					   5

/*
 * Max depth allowed in search tree during bulk inserts.  This is to keep from
 * degenerating to O(N^2) behavior when the tree is unbalanced due to sorted
 * or nearly-sorted input.  (Perhaps it would be better to use a balanced-tree
 * algorithm, but in common cases that would only add useless overhead.)
 */
#define GIN_MAX_TREE_DEPTH 100

/*
 * Page opaque data in a inverted index page.
 *
 * Note: GIN does not include a page ID word as do the other index types.
 * This is OK because the opaque data is only 8 bytes and so can be reliably
 * distinguished by size.  Revisit this if the size ever increases.
 */
typedef struct GinPageOpaqueData
{
	BlockNumber rightlink;		/* next page if any */
	OffsetNumber maxoff;		/* number entries on GIN_DATA page; number of
								 * heap ItemPointer on GIN_DATA|GIN_LEAF page
								 * and number of records on GIN_DATA &
								 * ~GIN_LEAF page. On GIN_LIST page, number of
								 * heap tuples. */
	uint16		flags;			/* see bit definitions below */
} GinPageOpaqueData;

typedef GinPageOpaqueData *GinPageOpaque;

#define GIN_DATA		  (1 << 0)
#define GIN_LEAF		  (1 << 1)
#define GIN_DELETED		  (1 << 2)
#define GIN_META		  (1 << 3)
#define GIN_LIST		  (1 << 4)
#define GIN_LIST_FULLROW  (1 << 5)		/* makes sense only on GIN_LIST page */

/* Page numbers of fixed-location pages */
#define GIN_METAPAGE_BLKNO	(0)
#define GIN_ROOT_BLKNO		(1)

typedef struct GinMetaPageData
{
	/*
	 * Pointers to head and tail of pending list, which consists of GIN_LIST
	 * pages.  These store fast-inserted entries that haven't yet been moved
	 * into the regular GIN structure.
	 */
	BlockNumber head;
	BlockNumber tail;

	/*
	 * Free space in bytes in the pending list's tail page.
	 */
	uint32		tailFreeSize;

	/*
	 * We store both number of pages and number of heap tuples that are in the
	 * pending list.
	 */
	BlockNumber nPendingPages;
	int64		nPendingHeapTuples;
} GinMetaPageData;

#define GinPageGetMeta(p) \
	((GinMetaPageData *) PageGetContents(p))

/*
 * Works on page
 */
#define GinPageGetOpaque(page) ( (GinPageOpaque) PageGetSpecialPointer(page) )

#define GinPageIsLeaf(page)    ( GinPageGetOpaque(page)->flags & GIN_LEAF )
#define GinPageSetLeaf(page)   ( GinPageGetOpaque(page)->flags |= GIN_LEAF )
#define GinPageSetNonLeaf(page)    ( GinPageGetOpaque(page)->flags &= ~GIN_LEAF )
#define GinPageIsData(page)    ( GinPageGetOpaque(page)->flags & GIN_DATA )
#define GinPageSetData(page)   ( GinPageGetOpaque(page)->flags |= GIN_DATA )
#define GinPageHasFullRow(page)    ( GinPageGetOpaque(page)->flags & GIN_LIST_FULLROW )
#define GinPageSetFullRow(page)   ( GinPageGetOpaque(page)->flags |= GIN_LIST_FULLROW )

#define GinPageIsDeleted(page) ( GinPageGetOpaque(page)->flags & GIN_DELETED)
#define GinPageSetDeleted(page)    ( GinPageGetOpaque(page)->flags |= GIN_DELETED)
#define GinPageSetNonDeleted(page) ( GinPageGetOpaque(page)->flags &= ~GIN_DELETED)

#define GinPageRightMost(page) ( GinPageGetOpaque(page)->rightlink == InvalidBlockNumber)

/*
 * We use our own ItemPointerGet(BlockNumber|GetOffsetNumber)
 * to avoid Asserts, since sometimes the ip_posid isn't "valid"
 */
#define GinItemPointerGetBlockNumber(pointer) \
	BlockIdGetBlockNumber(&(pointer)->ip_blkid)

#define GinItemPointerGetOffsetNumber(pointer) \
	((pointer)->ip_posid)

/*
 * Special-case item pointer values needed by the GIN search logic.
 *	MIN: sorts less than any valid item pointer
 *	MAX: sorts greater than any valid item pointer
 *	LOSSY PAGE: indicates a whole heap page, sorts after normal item
 *				pointers for that page
 * Note that these are all distinguishable from an "invalid" item pointer
 * (which is InvalidBlockNumber/0) as well as from all normal item
 * pointers (which have item numbers in the range 1..MaxHeapTuplesPerPage).
 */
#define ItemPointerSetMin(p)  \
	ItemPointerSet((p), (BlockNumber)0, (OffsetNumber)0)
#define ItemPointerIsMin(p)  \
	(GinItemPointerGetOffsetNumber(p) == (OffsetNumber)0 && \
	 GinItemPointerGetBlockNumber(p) == (BlockNumber)0)
#define ItemPointerSetMax(p)  \
	ItemPointerSet((p), InvalidBlockNumber, (OffsetNumber)0xffff)
#define ItemPointerIsMax(p)  \
	(GinItemPointerGetOffsetNumber(p) == (OffsetNumber)0xffff && \
	 GinItemPointerGetBlockNumber(p) == InvalidBlockNumber)
#define ItemPointerSetLossyPage(p, b)  \
	ItemPointerSet((p), (b), (OffsetNumber)0xffff)
#define ItemPointerIsLossyPage(p)  \
	(GinItemPointerGetOffsetNumber(p) == (OffsetNumber)0xffff && \
	 GinItemPointerGetBlockNumber(p) != InvalidBlockNumber)

typedef struct
{
	BlockIdData child_blkno;	/* use it instead of BlockNumber to save space
								 * on page */
	ItemPointerData key;
} PostingItem;

#define PostingItemGetBlockNumber(pointer) \
	BlockIdGetBlockNumber(&(pointer)->child_blkno)

#define PostingItemSetBlockNumber(pointer, blockNumber) \
	BlockIdSet(&((pointer)->child_blkno), (blockNumber))

/*
 * Support work on IndexTuple on leaf pages
 */
#define GinGetNPosting(itup)	GinItemPointerGetOffsetNumber(&(itup)->t_tid)
#define GinSetNPosting(itup,n)	ItemPointerSetOffsetNumber(&(itup)->t_tid,(n))
#define GIN_TREE_POSTING		((OffsetNumber)0xffff)
#define GinIsPostingTree(itup)	( GinGetNPosting(itup)==GIN_TREE_POSTING )
#define GinSetPostingTree(itup, blkno)	( GinSetNPosting((itup),GIN_TREE_POSTING ), ItemPointerSetBlockNumber(&(itup)->t_tid, blkno) )
#define GinGetPostingTree(itup) GinItemPointerGetBlockNumber(&(itup)->t_tid)

#define GinGetOrigSizePosting(itup) GinItemPointerGetBlockNumber(&(itup)->t_tid)
#define GinSetOrigSizePosting(itup,n)	ItemPointerSetBlockNumber(&(itup)->t_tid,(n))
#define GinGetPosting(itup)			( (ItemPointer)(( ((char*)(itup)) + SHORTALIGN(GinGetOrigSizePosting(itup)) )) )

#define GinMaxItemSize \
	MAXALIGN_DOWN(((BLCKSZ - SizeOfPageHeaderData - \
		MAXALIGN(sizeof(GinPageOpaqueData))) / 3 - sizeof(ItemIdData)))


/*
 * Data (posting tree) pages
 */
#define GinDataPageGetRightBound(page)	((ItemPointer) PageGetContents(page))
#define GinDataPageGetData(page)	\
	(PageGetContents(page) + MAXALIGN(sizeof(ItemPointerData)))
#define GinSizeOfItem(page) \
	(GinPageIsLeaf(page) ? sizeof(ItemPointerData) : sizeof(PostingItem))
#define GinDataPageGetItem(page,i)	\
	(GinDataPageGetData(page) + ((i)-1) * GinSizeOfItem(page))

#define GinDataPageGetFreeSpace(page)	\
	(BLCKSZ - MAXALIGN(SizeOfPageHeaderData) \
	 - MAXALIGN(sizeof(ItemPointerData)) \
	 - GinPageGetOpaque(page)->maxoff * GinSizeOfItem(page) \
	 - MAXALIGN(sizeof(GinPageOpaqueData)))

/*
 * List pages
 */
#define GinListPageSize  \
	( BLCKSZ - SizeOfPageHeaderData - MAXALIGN(sizeof(GinPageOpaqueData)) )

/*
 * Storage type for GIN's reloptions
 */
typedef struct GinOptions
{
	int32		vl_len_;		/* varlena header (do not touch directly!) */
	bool		useFastUpdate;	/* use fast updates? */
} GinOptions;

#define GIN_DEFAULT_USE_FASTUPDATE	true
#define GinGetUseFastUpdate(relation) \
	((relation)->rd_options ? \
	 ((GinOptions *) (relation)->rd_options)->useFastUpdate : GIN_DEFAULT_USE_FASTUPDATE)


#define GIN_UNLOCK	BUFFER_LOCK_UNLOCK
#define GIN_SHARE	BUFFER_LOCK_SHARE
#define GIN_EXCLUSIVE  BUFFER_LOCK_EXCLUSIVE

typedef struct GinState
{
	FmgrInfo	compareFn[INDEX_MAX_KEYS];
	FmgrInfo	extractValueFn[INDEX_MAX_KEYS];
	FmgrInfo	extractQueryFn[INDEX_MAX_KEYS];
	FmgrInfo	consistentFn[INDEX_MAX_KEYS];
	FmgrInfo	comparePartialFn[INDEX_MAX_KEYS];		/* optional method */

	bool		canPartialMatch[INDEX_MAX_KEYS];		/* can opclass perform
														 * partial match (prefix
														 * search)? */

	TupleDesc	tupdesc[INDEX_MAX_KEYS];
	TupleDesc	origTupdesc;
	bool		oneCol;
} GinState;

/* XLog stuff */

#define XLOG_GIN_CREATE_INDEX  0x00

#define XLOG_GIN_CREATE_PTREE  0x10

typedef struct ginxlogCreatePostingTree
{
	RelFileNode node;
	BlockNumber blkno;
	uint32		nitem;
	/* follows list of heap's ItemPointer */
} ginxlogCreatePostingTree;

#define XLOG_GIN_INSERT  0x20

typedef struct ginxlogInsert
{
	RelFileNode node;
	BlockNumber blkno;
	BlockNumber updateBlkno;
	OffsetNumber offset;
	bool		isDelete;
	bool		isData;
	bool		isLeaf;
	OffsetNumber nitem;

	/*
	 * follows: tuples or ItemPointerData or PostingItem or list of
	 * ItemPointerData
	 */
} ginxlogInsert;

#define XLOG_GIN_SPLIT	0x30

typedef struct ginxlogSplit
{
	RelFileNode node;
	BlockNumber lblkno;
	BlockNumber rootBlkno;
	BlockNumber rblkno;
	BlockNumber rrlink;
	OffsetNumber separator;
	OffsetNumber nitem;

	bool		isData;
	bool		isLeaf;
	bool		isRootSplit;

	BlockNumber leftChildBlkno;
	BlockNumber updateBlkno;

	ItemPointerData rightbound; /* used only in posting tree */
	/* follows: list of tuple or ItemPointerData or PostingItem */
} ginxlogSplit;

#define XLOG_GIN_VACUUM_PAGE	0x40

typedef struct ginxlogVacuumPage
{
	RelFileNode node;
	BlockNumber blkno;
	OffsetNumber nitem;
	/* follows content of page */
} ginxlogVacuumPage;

#define XLOG_GIN_DELETE_PAGE	0x50

typedef struct ginxlogDeletePage
{
	RelFileNode node;
	BlockNumber blkno;
	BlockNumber parentBlkno;
	OffsetNumber parentOffset;
	BlockNumber leftBlkno;
	BlockNumber rightLink;
} ginxlogDeletePage;

#define XLOG_GIN_UPDATE_META_PAGE 0x60

typedef struct ginxlogUpdateMeta
{
	RelFileNode node;
	GinMetaPageData metadata;
	BlockNumber prevTail;
	BlockNumber newRightlink;
	int32		ntuples;		/* if ntuples > 0 then metadata.tail was
								 * updated with that many tuples; else new sub
								 * list was inserted */
	/* array of inserted tuples follows */
} ginxlogUpdateMeta;

#define XLOG_GIN_INSERT_LISTPAGE  0x70

typedef struct ginxlogInsertListPage
{
	RelFileNode node;
	BlockNumber blkno;
	BlockNumber rightlink;
	int32		ntuples;
	/* array of inserted tuples follows */
} ginxlogInsertListPage;

#define XLOG_GIN_DELETE_LISTPAGE  0x80

#define GIN_NDELETE_AT_ONCE 16
typedef struct ginxlogDeleteListPages
{
	RelFileNode node;
	GinMetaPageData metadata;
	int32		ndeleted;
	BlockNumber toDelete[GIN_NDELETE_AT_ONCE];
} ginxlogDeleteListPages;


/* ginutil.c */
extern Datum ginoptions(PG_FUNCTION_ARGS);
extern void initGinState(GinState *state, Relation index);
extern Buffer GinNewBuffer(Relation index);
extern void GinInitBuffer(Buffer b, uint32 f);
extern void GinInitPage(Page page, uint32 f, Size pageSize);
extern void GinInitMetabuffer(Buffer b);
extern int	compareEntries(GinState *ginstate, OffsetNumber attnum, Datum a, Datum b);
extern int compareAttEntries(GinState *ginstate, OffsetNumber attnum_a, Datum a,
				  OffsetNumber attnum_b, Datum b);
extern Datum *extractEntriesS(GinState *ginstate, OffsetNumber attnum, Datum value,
				int32 *nentries, bool *needUnique);
extern Datum *extractEntriesSU(GinState *ginstate, OffsetNumber attnum, Datum value, int32 *nentries);

extern Datum gin_index_getattr(GinState *ginstate, IndexTuple tuple);
extern OffsetNumber gintuple_get_attrnum(GinState *ginstate, IndexTuple tuple);

/* gininsert.c */
extern Datum ginbuild(PG_FUNCTION_ARGS);
extern Datum gininsert(PG_FUNCTION_ARGS);
extern void ginEntryInsert(Relation index, GinState *ginstate,
			   OffsetNumber attnum, Datum value,
			   ItemPointerData *items, uint32 nitem,
			   bool isBuild);

/* ginxlog.c */
extern void gin_redo(XLogRecPtr lsn, XLogRecord *record);
extern void gin_desc(StringInfo buf, uint8 xl_info, char *rec);
extern void gin_xlog_startup(void);
extern void gin_xlog_cleanup(void);
extern bool gin_safe_restartpoint(void);

/* ginbtree.c */

typedef struct GinBtreeStack
{
	BlockNumber blkno;
	Buffer		buffer;
	OffsetNumber off;
	/* predictNumber contains prediction number of pages on current level */
	uint32		predictNumber;
	struct GinBtreeStack *parent;
} GinBtreeStack;

typedef struct GinBtreeData *GinBtree;

typedef struct GinBtreeData
{
	/* search methods */
	BlockNumber (*findChildPage) (GinBtree, GinBtreeStack *);
	bool		(*isMoveRight) (GinBtree, Page);
	bool		(*findItem) (GinBtree, GinBtreeStack *);

	/* insert methods */
	OffsetNumber (*findChildPtr) (GinBtree, Page, BlockNumber, OffsetNumber);
	BlockNumber (*getLeftMostPage) (GinBtree, Page);
	bool		(*isEnoughSpace) (GinBtree, Buffer, OffsetNumber);
	void		(*placeToPage) (GinBtree, Buffer, OffsetNumber, XLogRecData **);
	Page		(*splitPage) (GinBtree, Buffer, Buffer, OffsetNumber, XLogRecData **);
	void		(*fillRoot) (GinBtree, Buffer, Buffer, Buffer);

	bool		searchMode;

	Relation	index;
	GinState   *ginstate;
	bool		fullScan;
	bool		isBuild;

	BlockNumber rightblkno;

	/* Entry options */
	OffsetNumber entryAttnum;
	Datum		entryValue;
	IndexTuple	entry;
	bool		isDelete;

	/* Data (posting tree) option */
	ItemPointerData *items;
	uint32		nitem;
	uint32		curitem;

	PostingItem pitem;
} GinBtreeData;

extern GinBtreeStack *ginPrepareFindLeafPage(GinBtree btree, BlockNumber blkno);
extern GinBtreeStack *ginFindLeafPage(GinBtree btree, GinBtreeStack *stack);
extern Buffer ginStepRight(Buffer buffer, Relation index, int lockmode);
extern void freeGinBtreeStack(GinBtreeStack *stack);
extern void ginInsertValue(GinBtree btree, GinBtreeStack *stack);
extern void findParents(GinBtree btree, GinBtreeStack *stack, BlockNumber rootBlkno);

/* ginentrypage.c */
extern IndexTuple GinFormTuple(Relation index, GinState *ginstate,
			 OffsetNumber attnum, Datum key,
			 ItemPointerData *ipd, uint32 nipd, bool errorTooBig);
extern void GinShortenTuple(IndexTuple itup, uint32 nipd);
extern void prepareEntryScan(GinBtree btree, Relation index, OffsetNumber attnum,
				 Datum value, GinState *ginstate);
extern void entryFillRoot(GinBtree btree, Buffer root, Buffer lbuf, Buffer rbuf);
extern IndexTuple ginPageGetLinkItup(Buffer buf);

/* gindatapage.c */
extern int	compareItemPointers(ItemPointer a, ItemPointer b);
extern uint32 MergeItemPointers(ItemPointerData *dst,
				  ItemPointerData *a, uint32 na,
				  ItemPointerData *b, uint32 nb);

extern void GinDataPageAddItem(Page page, void *data, OffsetNumber offset);
extern void PageDeletePostingItem(Page page, OffsetNumber offset);

typedef struct
{
	GinBtreeData btree;
	GinBtreeStack *stack;
} GinPostingTreeScan;

extern GinPostingTreeScan *prepareScanPostingTree(Relation index,
					   BlockNumber rootBlkno, bool searchMode);
extern void insertItemPointer(GinPostingTreeScan *gdi,
				  ItemPointerData *items, uint32 nitem);
extern Buffer scanBeginPostingTree(GinPostingTreeScan *gdi);
extern void dataFillRoot(GinBtree btree, Buffer root, Buffer lbuf, Buffer rbuf);
extern void prepareDataScan(GinBtree btree, Relation index);

/* ginscan.c */

typedef struct GinScanEntryData *GinScanEntry;

typedef struct GinScanEntryData
{
	/* link to the equals entry in current scan key */
	GinScanEntry master;

	/*
	 * link to values reported to consistentFn, points to
	 * GinScanKey->entryRes[i]
	 */
	bool	   *pval;

	/* entry, got from extractQueryFn */
	Datum		entry;
	OffsetNumber attnum;
	Pointer		extra_data;

	/* Current page in posting tree */
	Buffer		buffer;

	/* current ItemPointer to heap */
	ItemPointerData curItem;

	/* partial match support */
	bool		isPartialMatch;
	TIDBitmap  *partialMatch;
	TBMIterator *partialMatchIterator;
	TBMIterateResult *partialMatchResult;
	StrategyNumber strategy;

	/* used for Posting list and one page in Posting tree */
	ItemPointerData *list;
	uint32		nlist;
	OffsetNumber offset;

	bool		isFinished;
	bool		reduceResult;
	uint32		predictNumberResult;
} GinScanEntryData;

typedef struct GinScanKeyData
{
	/* Number of entries in query (got by extractQueryFn) */
	uint32		nentries;

	/* array of ItemPointer result, reported to consistentFn */
	bool	   *entryRes;

	/* array of scans per entry */
	GinScanEntry scanEntry;
	Pointer    *extra_data;

	/* for calling consistentFn(GinScanKey->entryRes, strategy, query) */
	StrategyNumber strategy;
	Datum		query;
	OffsetNumber attnum;

	ItemPointerData curItem;
	bool		recheckCurItem;

	bool		firstCall;
	bool		isFinished;
} GinScanKeyData;

typedef GinScanKeyData *GinScanKey;

typedef struct GinScanOpaqueData
{
	MemoryContext tempCtx;
	GinState	ginstate;

	GinScanKey	keys;
	uint32		nkeys;
	bool		isVoidRes;		/* true if ginstate.extractQueryFn guarantees
								 * that nothing will be found */
} GinScanOpaqueData;

typedef GinScanOpaqueData *GinScanOpaque;

extern Datum ginbeginscan(PG_FUNCTION_ARGS);
extern Datum ginendscan(PG_FUNCTION_ARGS);
extern Datum ginrescan(PG_FUNCTION_ARGS);
extern Datum ginmarkpos(PG_FUNCTION_ARGS);
extern Datum ginrestrpos(PG_FUNCTION_ARGS);
extern void newScanKey(IndexScanDesc scan);

/* ginget.c */
extern PGDLLIMPORT int GinFuzzySearchLimit;

extern Datum gingetbitmap(PG_FUNCTION_ARGS);

/* ginvacuum.c */
extern Datum ginbulkdelete(PG_FUNCTION_ARGS);
extern Datum ginvacuumcleanup(PG_FUNCTION_ARGS);

/* ginarrayproc.c */
extern Datum ginarrayextract(PG_FUNCTION_ARGS);
extern Datum ginqueryarrayextract(PG_FUNCTION_ARGS);
extern Datum ginarrayconsistent(PG_FUNCTION_ARGS);

/* ginbulk.c */
typedef struct EntryAccumulator
{
	OffsetNumber attnum;
	Datum		value;
	uint32		length;
	uint32		number;
	ItemPointerData *list;
	bool		shouldSort;
	struct EntryAccumulator *left;
	struct EntryAccumulator *right;
} EntryAccumulator;

typedef struct
{
	GinState   *ginstate;
	EntryAccumulator *entries;
	uint32		maxdepth;
	EntryAccumulator **stack;
	uint32		stackpos;
	long		allocatedMemory;

	uint32		length;
	EntryAccumulator *entryallocator;
} BuildAccumulator;

extern void ginInitBA(BuildAccumulator *accum);
extern void ginInsertRecordBA(BuildAccumulator *accum,
				  ItemPointer heapptr,
				  OffsetNumber attnum, Datum *entries, int32 nentry);
extern ItemPointerData *ginGetEntry(BuildAccumulator *accum, OffsetNumber *attnum, Datum *entry, uint32 *n);

/* ginfast.c */

typedef struct GinTupleCollector
{
	IndexTuple *tuples;
	uint32		ntuples;
	uint32		lentuples;
	uint32		sumsize;
} GinTupleCollector;

extern void ginHeapTupleFastInsert(Relation index, GinState *ginstate,
					   GinTupleCollector *collector);
extern uint32 ginHeapTupleFastCollect(Relation index, GinState *ginstate,
						GinTupleCollector *collector,
						OffsetNumber attnum, Datum value, ItemPointer item);
extern void ginInsertCleanup(Relation index, GinState *ginstate,
				 bool vac_delay, IndexBulkDeleteResult *stats);

#endif   /* GIN_H */
