This matches an API already present in proto2
(const DescriptorPool* FileDescriptor::pool()).
However there is a slightly subtle implication here.
In proto2, the relationship between Descriptor and
MessageFactory is 1:many. You can create as many
DynamicMessageFactory instances as you want, and
each one will have its own independent DynamicMessage
prototype and computed layout for the same underlying
Descriptor. In practice the layouts will all be the same,
but one thing that could be distinct is that each can
have its own extension pool, which is a DescriptorPool
that will be searched for extensions when parsing.
In contrast, upb does not have a separate "message
factory" abstraction. That means that each upb_msgdef
has a single distinct layout, in other words a 1:1
correspondence between descriptor and layout. This means
that there is no way to create multiple message types
for the same descriptor that have distinct extension
pools. If you want a different set of extensions, you
must create a separate upb_symtab with a distinct set
of descriptors.
This change further entrenches that upb_filedef:upb_symtab
is a 1:1 relationship. A single upb_filedef cannot be a
member of multiple symbol tables. In practice this was
already true (there is no way to add a single filedef to
multiple symbol tables) but this change codifies this
1:1 relationship.
* Added -Wextra and -Wshorten-64-to-32 and fixed resulting errors.
* Disable -Wshorten-32-to-64 since Kokoro is missing Clang.
* Fixed -Wextra warnings for gcc.
* Reordered UPB_UNUSED() to come after declarations.
* Added another -pedantic fix and log CC version.
* Fix compile error and conditionally run use_bazel.sh.
* Moved set -e after use_bazel.sh.
* Fixed typo in conditional.
* WIP.
* WIP.
* Tests are passing.
* Recover some perf: LIKELY doesn't propagate through functions. :(
* Added some more benchmarks.
* Simplify & optimize upb_arena_realloc().
* Only add owned blocks to the freelist.
* More optimization/simplification.
* Re-fixed the bug.
* Revert unintentional changes to parser.rl.
* Revert Lua changes for now.
* Revert the arena fuse changes for now.
* Added last_size to the arena representation.
* Re-applied Lua changes.
* Implemented upb_arena_fuse().
* Fix the compile by re-ordering statements.
* Improve comments.
* [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.
* Removed reflection and other extraneous things from the core library.
* Added missing files and ran buildifier.
* New CMakeLists.txt.
* Made table its own cc_library() for internal usage.
- Foo_parsenew() -> Foo_parse().
- parse function takes plain (const char*, size_t) instead of
upb_strview. The latter is mainly useful for strings inside
message objects.
upb_msg was trying to be general enough that it could either live in
an arena or be allocated with malloc()/free(). This was too much
complexity for too little benefit. We should commit to just saying
that upb_msg is arena-only.
I also ripped out the code to glue upb_msg to the existing
handlers-based encoder/decoder. upb_msg has its own, small, simple
encoder/decoder. I'm trying to whittle down upb_msg to a small
and simple core.
I updated the Lua extension for these changes. Lua needs some more
work to properly create arenas per message. For now I just created
a single global arena.
Esun Kim
Joshua Haberman
Bo Yang