1/*-------------------------------------------------------------------------
2 *
3 * buffile.h
4 * Management of large buffered temporary files.
5 *
6 * The BufFile routines provide a partial replacement for stdio atop
7 * virtual file descriptors managed by fd.c. Currently they only support
8 * buffered access to a virtual file, without any of stdio's formatting
9 * features. That's enough for immediate needs, but the set of facilities
10 * could be expanded if necessary.
11 *
12 * BufFile also supports working with temporary files that exceed the OS
13 * file size limit and/or the largest offset representable in an int.
14 * It might be better to split that out as a separately accessible module,
15 * but currently we have no need for oversize temp files without buffered
16 * access.
17 *
18 * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
19 * Portions Copyright (c) 1994, Regents of the University of California
20 *
21 * src/include/storage/buffile.h
22 *
23 *-------------------------------------------------------------------------
24 */
25
26#ifndef BUFFILE_H
27#define BUFFILE_H
28
29#include "storage/sharedfileset.h"
30
31/* BufFile is an opaque type whose details are not known outside buffile.c. */
32
33typedef struct BufFile BufFile;
34
35/*
36 * prototypes for functions in buffile.c
37 */
38
39extern BufFile *BufFileCreateTemp(bool interXact);
40extern void BufFileClose(BufFile *file);
41extern size_t BufFileRead(BufFile *file, void *ptr, size_t size);
42extern size_t BufFileWrite(BufFile *file, void *ptr, size_t size);
43extern int BufFileSeek(BufFile *file, int fileno, off_t offset, int whence);
44extern void BufFileTell(BufFile *file, int *fileno, off_t *offset);
45extern int BufFileSeekBlock(BufFile *file, long blknum);
46extern int64 BufFileSize(BufFile *file);
47extern long BufFileAppend(BufFile *target, BufFile *source);
48
49extern BufFile *BufFileCreateShared(SharedFileSet *fileset, const char *name);
50extern void BufFileExportShared(BufFile *file);
51extern BufFile *BufFileOpenShared(SharedFileSet *fileset, const char *name);
52extern void BufFileDeleteShared(SharedFileSet *fileset, const char *name);
53
54#endif /* BUFFILE_H */
55