include/ext2fs/ext2_io.h

   1 /*
   2  * io.h --- the I/O manager abstraction
   3  *
   4  * Copyright (C) 1993, 1994, 1995, 1996 Theodore Ts'o.
   5  *
   6  * %Begin-Header%
   7  * This file may be redistributed under the terms of the GNU Public
   8  * License.
   9  * %End-Header%
  10  */
  11
  12 #ifndef _EXT2FS_EXT2_IO_H
  13 #define _EXT2FS_EXT2_IO_H
  14
  15 /*
  16  * ext2_loff_t is defined here since unix_io.c needs it.
  17  */
  18 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
  19 typedef long long       ext2_loff_t;
  20 #else
  21 typedef long            ext2_loff_t;
  22 #endif
  23
  24 /* llseek.c */
  25 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
  26
  27 typedef struct struct_io_manager *io_manager;
  28 typedef struct struct_io_channel *io_channel;
  29
  30 #define CHANNEL_FLAGS_WRITETHROUGH      0x01
  31
  32 struct struct_io_channel {
  33         errcode_t       magic;
  34         io_manager      manager;
  35         char            *name;
  36         int             block_size;
  37         errcode_t       (*read_error)(io_channel channel,
  38                                       unsigned long block,
  39                                       int count,
  40                                       void *data,
  41                                       size_t size,
  42                                       int actual_bytes_read,
  43                                       errcode_t error);
  44         errcode_t       (*write_error)(io_channel channel,
  45                                        unsigned long block,
  46                                        int count,
  47                                        const void *data,
  48                                        size_t size,
  49                                        int actual_bytes_written,
  50                                        errcode_t error);
  51         int             refcount;
  52         int             flags;
  53         int             reserved[14];
  54         void            *private_data;
  55         void            *app_data;
  56 };
  57
  58 struct struct_io_manager {
  59         errcode_t magic;
  60         const char *name;
  61         errcode_t (*open)(const char *name, int flags, io_channel *channel);
  62         errcode_t (*close)(io_channel channel);
  63         errcode_t (*set_blksize)(io_channel channel, int blksize);
  64         errcode_t (*read_blk)(io_channel channel, unsigned long block,
  65                               int count, void *data);
  66         errcode_t (*write_blk)(io_channel channel, unsigned long block,
  67                                int count, const void *data);
  68         errcode_t (*flush)(io_channel channel);
  69         errcode_t (*write_byte)(io_channel channel, unsigned long offset,
  70                                 int count, const void *data);
  71         int             reserved[15];
  72 };
  73
  74 #define IO_FLAG_RW      1
  75
  76 /*
  77  * Convenience functions....
  78  */
  79 #define io_channel_close(c)             ((c)->manager->close((c)))
  80 #define io_channel_set_blksize(c,s)     ((c)->manager->set_blksize((c),s))
  81 #define io_channel_read_blk(c,b,n,d)    ((c)->manager->read_blk((c),b,n,d))
  82 #define io_channel_write_blk(c,b,n,d)   ((c)->manager->write_blk((c),b,n,d))
  83 #define io_channel_flush(c)             ((c)->manager->flush((c)))
  84 #define io_channel_write_byte(c,b,n,d)  ((c)->manager->write_byte((c),b,n,d))
  85 #define io_channel_bumpcount(c)         ((c)->refcount++)
  86
  87 /* unix_io.c */
  88 extern io_manager unix_io_manager;
  89
  90 /* test_io.c */
  91 extern io_manager test_io_manager, test_io_backing_manager;
  92 extern void (*test_io_cb_read_blk)
  93         (unsigned long block, int count, errcode_t err);
  94 extern void (*test_io_cb_write_blk)
  95         (unsigned long block, int count, errcode_t err);
  96 extern void (*test_io_cb_set_blksize)
  97         (int blksize, errcode_t err);
  98
  99 #endif /* _EXT2FS_EXT2_IO_H */
 100