Giovanni Campagna authored Apr 19, 2013 and Philip Chimento committed Aug 01, 2020

The marshalling metadata, as stored in the typelib, is not a format
friendly to gjs, and requires to have multiple switches and a complex
logic in the hot path of function calls.
Instead, extend the current caching mechanism to allow arbitrary
data to be attached to arguments, and to have it deal with JS arguments,
rather than a mixture of C and GI arguments.

(Philip Chimento: rebased and fixed coding style and bugs.)