lib/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 /*
  13  * ext2_loff_t is defined here since unix_io.c needs it.
  14  */
  15 #if defined(__GNUC__) || defined(HAS_LONG_LONG)
  16 typedef long long       ext2_loff_t;
  17 #else
  18 typedef long            ext2_loff_t;
  19 #endif
  20
  21 /* llseek.c */
  22 ext2_loff_t ext2fs_llseek (int, ext2_loff_t, int);
  23
  24 typedef struct struct_io_manager *io_manager;
  25 typedef struct struct_io_channel *io_channel;
  26
  27 struct struct_io_channel {
  28         errcode_t       magic;
  29         io_manager      manager;
  30         char            *name;
  31         int             block_size;
  32         errcode_t       (*read_error)(io_channel channel,
  33                                       unsigned long block,
  34                                       int count,
  35                                       void *data,
  36                                       size_t size,
  37                                       int actual_bytes_read,
  38                                       errcode_t error);
  39         errcode_t       (*write_error)(io_channel channel,
  40                                        unsigned long block,
  41                                        int count,
  42                                        const void *data,
  43                                        size_t size,
  44                                        int actual_bytes_written,
  45                                        errcode_t error);
  46         int             refcount;
  47         int             reserved[15];
  48         void            *private_data;
  49         void            *app_data;
  50 };
  51
  52 struct struct_io_manager {
  53         errcode_t magic;
  54         const char *name;
  55         errcode_t (*open)(const char *name, int flags, io_channel *channel);
  56         errcode_t (*close)(io_channel channel);
  57         errcode_t (*set_blksize)(io_channel channel, int blksize);
  58         errcode_t (*read_blk)(io_channel channel, unsigned long block,
  59                               int count, void *data);
  60         errcode_t (*write_blk)(io_channel channel, unsigned long block,
  61                                int count, const void *data);
  62         errcode_t (*flush)(io_channel channel);
  63         int             reserved[16];
  64 };
  65
  66 #define IO_FLAG_RW      1
  67
  68 /*
  69  * Convenience functions....
  70  */
  71 #define io_channel_close(c)             ((c)->manager->close((c)))
  72 #define io_channel_set_blksize(c,s)     ((c)->manager->set_blksize((c),s))
  73 #define io_channel_read_blk(c,b,n,d)    ((c)->manager->read_blk((c),b,n,d))
  74 #define io_channel_write_blk(c,b,n,d)   ((c)->manager->write_blk((c),b,n,d))
  75 #define io_channel_flush(c)             ((c)->manager->flush((c)))
  76 #define io_channel_bumpcount(c)         ((c)->refcount++)
  77
  78 /* unix_io.c */
  79 extern io_manager unix_io_manager;
  80
  81 /* test_io.c */
  82 extern io_manager test_io_manager, test_io_backing_manager;
  83 extern void (*test_io_cb_read_blk)
  84         (unsigned long block, int count, errcode_t err);
  85 extern void (*test_io_cb_write_blk)
  86         (unsigned long block, int count, errcode_t err);
  87 extern void (*test_io_cb_set_blksize)
  88         (int blksize, errcode_t err);