Using `.ok()` is more concise when loosing error context in favour of a
simple `None` value.
Automatic replacement SSR pattern in rust-analyzer:
{let $a = $b;match $c {Ok($d) => Some($e), Err(_) => None }} ==>> {$b.ok()}
Note that rust-analyzer does not support:
- duplicate labels (ie. $c should be equal to $a, and $e equal to $d);
- statement lists yet, hence both sides are wrapped in braces.
But it performs the desired operation well enough here.
SDPMessage, FlowCombiner and ParseContext have specific functions
available to perform copying, freeing and (un)ref'ing. Calling them
directly on versions where they are supported prevents us from going
through GType machinery and locks that end up the same functions in the
end.
For SDPMessageRef, StructureRef and CapsFeatureRef this involves the
conversion from and to a glib::Value. Specifically this means that e.g.
a StructureRef can be retrieved from a glib::Value via borrowing, i.e.
without creating a copy of the structure first.
For all mini objects only retrieval from a glib::Value is implemented as
the other direction would allow to get multiple immutable references
from a mutable reference without borrowing, which is not allowed and
would make it possible to observe a mini object changing while having an
immutable reference to it.
It's forbidden to provide an index higher than the number of elements in
the array, and will cause crashes or other undesired outcomes.
Also the insert() API should take an Option<u32> instead of an i32 that
might also be -1 for appending. It's awful API otherwise.
