there was a function to "abbreviate" sizes, but it was somewhat
unclear and incomplete. reuse the sizeof_fmt_* set of functions from
the borg backup project (MIT licensed) to implement a more complete
and flexible display that will scale up to the Yottabyte and
beyond. it also supports non-IEC units (like "kibibyte", AKA 1024
bytes) if you fancy that stuff.
this is a workaround for #91: it allows users to better see the size
of the file that will be transfered.
*some* places are still kept in bytes, most notably when receive fails
to receive all bytes ("got %d bytes, wanted %d") because we may want
more clarity there.
text transfers also use the "bytes" suffix (instead of "B") because it
will commonly not reach beyond the KiB range.
note that the test suite only covers decimal (non-IEC) prefix, but it
is assumed to be sufficient to be considered correct.
This will allow a future peer to figure out what transit modes we can
and cannot do, and thus avoid spinning up expensive modes that we won't
be able to use (e.g. WebRTC).
This enhances the ACK that wormhole-receive returns when it finishes
receiving all the data to be a dictionary. The dict includes the SHA256
hash of everything it received, and the sender checks this for a match
before declaring the transfer to be a success. This guards against data
being shuffled somehow during transit.
The file-send protocol now sends a "hints-v1" key in the "transit"
message, which contains a list of JSON data structures that describe the
connection hints (a mixture of direct, tor, and relay hints, for now).
Previously the direct/tor and relay hints were sent in different keys,
and all were sent as strings like "tcp:hostname:1234" which had to be
parsed by the recipient.
The new structures include a version string, to make it easier to add
new types in the future. Transit logs+ignores hints it cannot
understand.
In the future, both sides should expect to receive "transit" messages at
any time, and they will add to the list of hints that they should try.
For now, each side only sends a single transit message, before they send
the offer (sender) or answer (receiver).
This moves us slowly towards a file-transfer protocol that exchanges
multiple messages, with a single offer (sender->receiver) and
answer (receiver->sender), and one or more connection hint messages (in
either direction) that appear gradually over time as connection
providers come online.
At present the protocol still expects the whole hint list to be present
in the offer/answer message.
One downside is that we keep the wormhole channel allocated longer (we
have to finish the file transfer before we can deallocate it, which
could take a while for large files). Maybe we can fix this in the
future.
Also clean up test_scripts.PregeneratedCode:
* fetch results from both sides at the same time
* only check rc when using a subprocess, since the direct call doesn't
use rc=0 anymore
* no need to cancel the other side's Deferred when one errors
* provide more information if stderr was non-empty
