[tor-bugs] #12202 [Tor]: Refactor: Improve interface of `entry_is_live`

[Tor Bug Tracker & Wiki]

#12202: Refactor: Improve interface of `entry_is_live`
-------------------------+---------------------
 Reporter:  asn          |          Owner:
     Type:  enhancement  |         Status:  new
 Priority:  minor        |      Milestone:
Component:  Tor          |        Version:
 Keywords:  tor-guard    |  Actual Points:
Parent ID:               |         Points:
-------------------------+---------------------
 `entry_is_live()` checks whether a given entry guard can be used. It
 accepts as arguments a couple of flags that we might want the entry guard
 to have.

 Its signature is:
 {{{
 static INLINE const node_t *
 entry_is_live(const entry_guard_t *e, int need_uptime, int need_capacity,
               int assume_reachable, int need_descriptor, const char **msg)
 }}}

 Which results in calls like this:
 {{{
       if (entry_is_live(entry, 0, 1, 0, !for_directory, &msg))
 }}}
 {{{
      if (entry_is_live(e, 0, 1, 0, 0, &msg))
 }}}
 {{{
       const node_t *r = entry_is_live(entry, 0, 1, 0, 0, &live_msg);
 }}}

 It would probably be better if we turn those boolean flags into a
 bitstring (maybe similar to `router_crn_flags_t`), so that the calls are
 more readable.

 This is just code refactoring and should result in no behavior changes.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/12202>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online