Proposal: TFCL [Tox Friend Capabilities Level]

[iphydf]

Based on #777.

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TFCL [Tox Friend Capabilities Level]

add a number (a bit like Android API Level) to know what capabilites a node (Friend) has.
so clients can react accordingly. (using a newer API, and so on ...)

getting the capabilites_level for a friend

keep old API function:
TOX_CONNECTION tox_friend_get_connection_status(const Tox *tox, uint32_t friend_number, TOX_ERR_FRIEND_QUERY *error);

and add a new one:
TOX_CONNECTION tox_friend_get_connection_status_v2(const Tox *tox, uint32_t friend_number, uint32_t *capabilites_level, TOX_ERR_FRIEND_QUERY *error);

keep old API function:
void tox_callback_friend_connection_status(Tox *tox, tox_friend_connection_status_cb *callback);

and add a new one:
void tox_callback_friend_connection_status_v2(Tox *tox, tox_friend_connection_status_cb_v2 *callback);

keep old API function:
typedef void tox_friend_connection_status_cb(Tox *tox, uint32_t friend_number, TOX_CONNECTION connection_status, void *user_data);

and add a new one:
typedef void tox_friend_connection_status_cb_v2(Tox *tox, uint32_t friend_number, uint32_t capabilites_level, TOX_CONNECTION connection_status, void *user_data);

getting the capabilites_level of own node

at runtime

add new API function:
uint32_t tox_self_get_capabilites_level();

at compile time

in toxcore/tox.h

#define TOX_CAPABILITY_LEVEL 3

description of capabilites_level value

capabilites_level	added capabilities
0	Tox Base capabilites as of c-toxcore v0.1.11
1	added Video Fix
2	added MessageV2 capability
3	added persistent Conferences
...	...
...	...

[hugbubby]

Opinion: Capabilities levels should not reference specific, added capabilities, they should reference version numbers or releases that themselves come along with the implication of those things. Toxcore should hold a list of capabilities associated with different clients, forks, and releases - and it should send unique version IDs, not attempt to pack in every feature into a 64 bit integer.

I think that mightve been what you were going for with this but anyways.

[iphydf]

We'll have capabilities, but not like in this proposal.