In most places where pointer can be an 'error' it cannot be null
pointer. Further, in those cases just calling PTR_ERR() is not enough
to handle the null case. Simplify code by removing this case.
If NULL case needs to be handled, it's better to add separate check
and return fixed error code in that case.
- apk_istream_splice usage is converted to apk_stream_copy which
is the newer variant. With caching enabled by default, this
makes more sense mmapping or using separate buffers.
- apk_istream_tee is reworked to write to apk_ostream, which simplifies
quite a bit of various things
It turns out inflate() can output zero bytes, even if it consumed
data. This had the unfortunate side effect of returning zero bytes
(end-of-file) condition before calling the boundary callbacks. This
fixes the logic to not return zero reads on gzip boundary.
In practice this fixes the seldom seen issues of apk reporting
bad signature (when it was correct).
Timo Teräs