Improve handling of peers entering and leaving conferences

[zugz]

(based on #1266)

• delete existing peers with same real_pk on adding a peer
• send freeze packet on quit

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This change is 

[hugbubby]

Make sure you run astyle so Travis doesn't freak out.

[hugbubby]

You also need to fix the codefactor issues. 3 of them are about there being redundant or unnecessary newlines, one is because a method in this patch is more "complex" than codefactor likes (has too many arguments, return paths, etc.)

[codecov]

Codecov Report

Merging #1267 into master will increase coverage by <.1%.
The diff coverage is 96.5%.

@@           Coverage Diff            @@
##           master   #1267     +/-   ##
========================================
+ Coverage      83%     83%   +<.1%     
========================================
  Files          82      82             
  Lines       14928   14957     +29     
========================================
+ Hits        12392   12418     +26     
- Misses       2536    2539      +3

Impacted Files	Coverage Δ
toxcore/group.c	78.7% <96.5%> (+0.3%)	⬆️
toxcore/LAN_discovery.c	84.9% <0%> (-1%)	⬇️
toxcore/onion_client.c	95.3% <0%> (-0.7%)	⬇️
toxcore/friend_connection.c	94.6% <0%> (-0.3%)	⬇️
toxav/toxav.c	67.6% <0%> (ø)	⬆️
toxcore/DHT.c	77.8% <0%> (ø)	⬆️
toxav/msi.c	65.6% <0%> (+1.1%)	⬆️

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[anthonybilinski]

From my own use, I used to reproduce a corruption of the tox savefile frequently when running off tip. Since I switched to this PR branch, I haven't seen it once.

To recover from the corrupt save file, downgrading toxcore to before persistent conferences were introduced, loading then saving, then upgrading to this PR should fix it. Upgrading to this PR directly from a corrupt save file on tip will just fail to load completely.

[sudden6]

Reviewed 7 of 8 files at r1, 1 of 1 files at r2.
Reviewable status: 0 of 1 approvals obtained (waiting on @zugz)

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toxcore/group.c, line 472 at r1 (raw file):

}

static bool delete_frozen(Group_c *g, uint32_t frozen_index)

add nullptr check or comment that g must not be nullptr

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toxcore/group.c, line 1713 at r1 (raw file):

 * return -1 on failure
 */
static int group_leave(const Group_Chats *g_c, uint32_t groupnumber, bool permanent)

why change the return type? IIRC we're trying to use bool for success/failure return codes

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toxcore/group.c, line 1678 at r2 (raw file):

 * return -1 on failure
 */
static int group_freeze_peer_send(const Group_Chats *g_c, uint32_t groupnumber, uint16_t peer_num)

use bool for success/error return types?

[robinlinden]

Reviewable status: 0 of 1 approvals obtained (waiting on @sudden6 and @zugz)

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toxcore/group.c, line 472 at r1 (raw file):

Previously, sudden6 wrote…

add nullptr check or comment that g must not be nullptr

That's fine for functions in the public API, but I think that's unnecessary for things that are only used internally in Toxcore.

[sudden6]

Reviewed 1 of 1 files at r3.
Reviewable status: 0 of 1 approvals obtained

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toxcore/group.c, line 472 at r1 (raw file):

Previously, robinlinden (Robin Lindén) wrote…

That's fine for functions in the public API, but I think that's unnecessary for things that are only used internally in Toxcore.

ok, ignoring this then.

[anthonybilinski]

#1285 may be related to this change.