pack-bitmap.c: hide bitmap internals in `read_u8()`

The `read_u8()` helper function internal to pack-bitmap.c was defined in
b5007211b6 (pack-bitmap: do not use gcc packed attribute, 2014-11-27).

Prior to b5007211b6, callers within pack-bitmap.c would read an
individual unsigned integer by doing something like:

    struct bitmap_disk_entry *e;

    e = (struct bitmap_disk_entry *)(index->map + index->map_pos);
    index->map_pos += sizeof(*e);

...which relied on the fact that the `bitmap_disk_entry` struct was
defined with `__attribute((packed))`, which b5007211b6 sought to get rid
of since the `__attribute__` flag is a noop on some compilers (which
makes the above code rely on the absence of padding to be correct).

So b5007211b6 got rid of the above convention and replaced it by reading
individual fields of that structure with a `read_u8()` helper that reads
from the region of memory pointed to by `->map`, and updates the
`->map_pos` pointer accordingly.

But this forces callers to be intimately aware of `bitmap_git->map` and
`bitmap_git->map_pos`. Instead, teach `read_u8()` to take a `struct
bitmap_index *` directly, and avoid having callers deal with the
internals themselves.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

0 files changed, 0 insertions, 0 deletions