Use `utils::linearizing_input_stream` for the deserizalization of the
collection. Allows for avoiding the linearization of the entire cell
value, instead only linearizing individual values as they are
deserialized from the buffer.
We could use iterators over cells instead of a vector of cells
in collection_mutation(_view)_description. Then some use cases could
provide iterators that construct the cells "on the fly".
The purpose of collection_type_impl::to_value was to serialize a
collection for sending over CQL. The corresponding function in origin
is called serializeForNativeProtocol, but the name is a bit lengthy,
so I settled for serialize_for_cql.
The method now became a free-standing function, using the visit
function to perform a dispatch on the collection type instead
of a virtual call. This also makes it easier to generalize it to UDTs
in future commits.
Remove the old serialize_for_native_protocol with a FIXME: implement
inside. It was already implemented (to_value), just called differently.
remove dead methods: enforce_limit and serialized_values. The
corresponding methods in C* are auxiliary methods used inside
serializeForNativeProtocol. In our case, the entire algorithm
is wholly written in serialize_for_cql.
`collection_type_impl::serialize_mutation_form`
became `collection_mutation(_view)_description::serialize`.
Previously callers had to cast their data_type down to collection_type
to use serialize_mutation_form. Now it's done inside `serialize`.
In the future `serialize` will be generalized to handle UDTs.
`collection_type_impl::deserialize_mutation_form`
became a free standing function `deserialize_collection_mutation`
with similiar benefits. Actually, noone needs to call this function
manually because of the next paragraph.
A common pattern consisting of linearizing data inside a `collection_mutation_view`
followed by calling `deserialize_mutation_form` has been abstracted out
as a `with_deserialized` method inside collection_mutation_view.
serialize_mutation_form_only_live was removed,
because it hadn't been used anywhere.
collection_type_impl::mutation became collection_mutation_description.
collection_type_impl::mutation_view became collection_mutation_view_description.
These classes now reside inside collection_mutation.hh.
Additional documentation has been written for these classes.
Related function implementations were moved to collection_mutation.cc.
This makes it easier to generalize these classes to non-frozen UDTs in future commits.
The new names (together with documentation) better describe their purpose.
The classes 'collection_mutation' and 'collection_mutation_view'
were moved to a separate header, collection_mutation.hh.
Implementations of functions that operate on these classes,
including some methods of collection_type_impl, were moved
to a separate compilation unit, collection_mutation.cc.
This makes it easier to modify these structures in future commits
in order to generalize them for non-frozen User Defined Types.
Some additional documentation has been written for collection_mutation.
