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File Content: `large_object.h`

/*-------------------------------------------------------------------------
 *
 * large_object.h
 *	  Declarations for PostgreSQL large objects.  POSTGRES 4.2 supported
 *	  zillions of large objects (internal, external, jaquith, inversion).
 *	  Now we only support inversion.
 *
 * Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * src/include/storage/large_object.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef LARGE_OBJECT_H
#define LARGE_OBJECT_H

#include "utils/snapshot.h"


/*----------
 * Data about a currently-open large object.
 *
 * id is the logical OID of the large object
 * snapshot is the snapshot to use for read/write operations
 * subid is the subtransaction that opened the desc (or currently owns it)
 * offset is the current seek offset within the LO
 * flags contains some flag bits
 *
 * NOTE: before 7.1, we also had to store references to the separate table
 * and index of a specific large object.  Now they all live in pg_largeobject
 * and are accessed via a common relation descriptor.
 *----------
 */
typedef struct LargeObjectDesc
{
	Oid			id;				/* LO's identifier */
	Snapshot	snapshot;		/* snapshot to use */
	SubTransactionId subid;		/* owning subtransaction ID */
	uint32		offset;			/* current seek pointer */
	int			flags;			/* locking info, etc */

/* flag bits: */
#define IFS_RDLOCK		(1 << 0)
#define IFS_WRLOCK		(1 << 1)

} LargeObjectDesc;


/*
 * Each "page" (tuple) of a large object can hold this much data
 *
 * We could set this as high as BLCKSZ less some overhead, but it seems
 * better to make it a smaller value, so that not as much space is used
 * up when a page-tuple is updated.  Note that the value is deliberately
 * chosen large enough to trigger the tuple toaster, so that we will
 * attempt to compress page tuples in-line.  (But they won't be moved off
 * unless the user creates a toast-table for pg_largeobject...)
 *
 * Also, it seems to be a smart move to make the page size be a power of 2,
 * since clients will often be written to send data in power-of-2 blocks.
 * This avoids unnecessary tuple updates caused by partial-page writes.
 */
#define LOBLKSIZE		(BLCKSZ / 4)


/*
 * Function definitions...
 */

/* inversion stuff in inv_api.c */
extern void close_lo_relation(bool isCommit);
extern Oid	inv_create(Oid lobjId);
extern LargeObjectDesc *inv_open(Oid lobjId, int flags, MemoryContext mcxt);
extern void inv_close(LargeObjectDesc *obj_desc);
extern int	inv_drop(Oid lobjId);
extern int	inv_seek(LargeObjectDesc *obj_desc, int offset, int whence);
extern int	inv_tell(LargeObjectDesc *obj_desc);
extern int	inv_read(LargeObjectDesc *obj_desc, char *buf, int nbytes);
extern int	inv_write(LargeObjectDesc *obj_desc, const char *buf, int nbytes);
extern void inv_truncate(LargeObjectDesc *obj_desc, int len);

#endif   /* LARGE_OBJECT_H */

Name	Size	Permission
backendid.h	730 bytes	0644
barrier.h	6755 bytes	0644
block.h	3282 bytes	0644
buf.h	1082 bytes	0644
buf_internals.h	7980 bytes	0644
buffile.h	1714 bytes	0644
bufmgr.h	7377 bytes	0644
bufpage.h	13218 bytes	0644
copydir.h	561 bytes	0644
fd.h	3649 bytes	0644
freespace.h	1264 bytes	0644
fsm_internals.h	2296 bytes	0644
indexfsm.h	795 bytes	0644
ipc.h	2601 bytes	0644
item.h	469 bytes	0644
itemid.h	4342 bytes	0644
itemptr.h	3813 bytes	0644
large_object.h	2964 bytes	0644
latch.h	5403 bytes	0644
lmgr.h	3298 bytes	0644
lock.h	21669 bytes	0644
lwlock.h	3665 bytes	0644
off.h	1618 bytes	0644
pg_sema.h	2470 bytes	0644
pg_shmem.h	2001 bytes	0644
pmsignal.h	2080 bytes	0644
pos.h	1593 bytes	0644
predicate.h	2623 bytes	0644
predicate_internals.h	17386 bytes	0644
proc.h	9805 bytes	0644
procarray.h	3027 bytes	0644
procsignal.h	1798 bytes	0644
reinit.h	588 bytes	0644
relfilenode.h	4417 bytes	0644
s_lock.h	28675 bytes	0644
shmem.h	2694 bytes	0644
sinval.h	5091 bytes	0644
sinvaladt.h	1523 bytes	0644
smgr.h	5805 bytes	0644
spin.h	2775 bytes	0644
standby.h	4067 bytes	0644

File Content: large_object.h

File Content: `large_object.h`