* refactor: encapsulate request tracking in a class
Introduces a new class to peer-mgr, `ClientRequests`, which tracks what
active requests we've got pending: which blocks, when the requests were
sent, and who they were sent to.
This shouldn't change peer-mgr behavior. Its goal is to carve out some
of peer-mgr's data structures and encapsulte them behind an API that's
simpler to understand.
* refactor: move ActiveRequests to its own file
* perf: avoid duplicate call to tr_cpMissingBlocksInPiece
* refactor: [[maybe_unused]] iff arg _might_ be used
If the arg is never used, comment out its name.
If the arg is _sometimes_ used e.g. with ifdefs, use [[maybe_unused]].
Port libtransmission to C++. This PR doesn't refactor everything to c++.
Its code changes are only what was necessary to compile and link as c++.
See libtransmission/README.md for details on how to submit modernization
patches!
Co-authored-by: Mike Gelfand <mikedld@mikedld.com>