* [textformat]: added missing newline when a message opens.
* Added tostring() support to Lua that prints to text format.
Also fixed a gnarly bug that this exposed.
Map parsing/serializing relies on map entries always
having a predictable order. The code that generates
layout was not respecting this in the case of string
keys and primitive values.
This involves:
- remove upb_msglayout -> upb_msgfactory dependency.
- remove upb_msglayout -> upb_msgdef dependency (in progress).
- make upb_msglayout use a representation that can be
statically initialized by generated code.
The goal here is that upb_msglayout becomes a kind of "descriptor
lite": it contains enough data to parser and serialize protobufs
and manipulate a upb_msg in memory, while being far smaller and
simpler than a full descriptor. It also does not include field
names, which can be a benefit for applications that do not want
to leak field names.
Generated code can then create a upb_msglayout, and do most things
without ever needing to construct full descriptors/defs if they
don't want to.
* Put oneofs in the same table as fields.
Oneofs and fields are not allowed to have names that conflict,
so we might as well put them all in the same table. This also
allows an efficient operation that looks for both fields and
oneofs in a single lookup.
Added support for OneofDef to Lua to allow testing of this.
* Addressed PR comments.
Joshua Haberman