This avoids blocks corruption in case webseed provides bad data.
As explained by cfpp2p, "The requirements to reproduce are at least one
webseed that sends corrupt block(s), and at least one other peer (webseed
or regular peer) that sends correct data for the same block. Then a peer
with correct block sends the block and transmission accepts and verifies
that block as good. But then the webseed thread comes around and the same
block is downloaded from the webseed that sends a bad block which is then
written even though the piece was previously deemed complete."
1. add the option the code to be used under GPLv2 or GPLv3; previously only GPLv2 was allowed
2. add the "proxy option" as described in GPLv3 so we can add future licenses without having to bulk-edit everything again :)
3. remove the awkward "exception for MIT code in Mac client" clause; it was unnecessary and confusing.
1. move the callback structs' declarations next to the callback functions where they're used.
2. rename the callback structs to clarify their link to the callback functions.
3. constify some of the callback functions' local variables.
4. clarify some of the comments.
This is partially to address #4145 "Downloads stuck at 100%" by refactoring the bitset, bitfield, and tr_completion; however, the ripple effect is larger than usual so things may get worse in the short term before getting better.
livings124: to fix the mac build, remove bitset.[ch] from xcode
This commit, started by a patch from athy, implements a rarest first policy when deciding which pieces to request from peers. It keeps a count of how many peers have each piece, and updates the count when getting bitfields, have, have all, and have none messages, as well as decrementing the counts when peers disconnect.
This running total is generated only for downloading torrents. Seeds don't have this overhead.
This patch adds two new flags to the callback function -- did_connect and did_timeout -- that are calculated inside of web.c using information from libcurl. This allows the announcer to detect timeouts more accurately and also to distinguish between unresponsive peers (which get the preexisting "Tracker did not respond" error message) and unconnectable peers (which get a new error message, "Could not connect to tracker").
This is caused by libtransmission using tr_webseedIsActive() in two ways: (1) webseed.c uses it to know if there are any pending requests, and (2) tr_torrentStat() uses it to set tr_stat.webseedsSendingToUs. Having a queued task isn't enough to be "active" in use (2) -- it needs to know if the webseed is actually sending data. These two uses should be moved into separate functions.
Mike Gelfand