torrent: cancelBlocks on wire 'close'

[astro]

We may need to add even more logic: malicious peers may hold back responses indefinitely. What do you think about request timeouts?

(Albeit not for malicious reasons, I once got no response from certain peers when choosing a wrong request size (> 16 KB)).

[feross]

@astro When a wire emits finish, all pending request callbacks are called with errors. Code here: https://github.com/feross/bittorrent-protocol/blob/c41d091549dc15261f81d3c22d6d59771a6b9cf1/index.js#L620-L621

This will be handled in gotPiece in torrent.js here: https://github.com/feross/webtorrent/blob/25c6a10e3180b4aeea1c36f8d57ad66a0e599b52/lib/torrent.js#L966 where storage.cancelBlock is called.

Unless I'm mistaken, this PR shouldn't be necessary! Do you agree?

[feross]

malicious peers may hold back responses indefinitely. What do you think about request timeouts?

Timeouts are already handled by bittorrent-protocol here: https://github.com/feross/bittorrent-protocol/blob/c41d091549dc15261f81d3c22d6d59771a6b9cf1/index.js#L450 as long as we call wire.setTimeout in torrent.js, which we are.

[feross]

There's even a test verifying that timeouts work as expected here: https://github.com/feross/bittorrent-protocol/blob/master/test/timeout.js

[astro]

you're right.