This CL implements Maps for scalar types for the C++ runtime. It's orthogonal to cl/580453646. This CL is constrained by having to force template instantiation of proto2::Map<K, V>. Put differently, a Rust protobuf::Map<K, V> implementation needs to call 'extern "C"' functions with both key and value type in the function name (e.g. __pb_rust_Map_i32_f64_get()). We use macros to generate a Map implementation for every (K,V)-pair. An alternative would have been to use vtables.
Luckily a key in a protobuf map can only be integer types, bool and string. So the number of key types is bounded by the specification, while the number of value types is not i.e. any protobuf message can be a value in a map. Given these constraints we introduce one 'MapKeyOps' trait per key type e.g. MapKeyBOOLOps or MapKeyI32Ops. These traits need to be implemented for every value type e.g. 'impl MapKeyBOOLOps for i32' will implement 'Map::<bool, i32>'. In particular the MapKeyOps traits can also be implemented for generated messages without violating the orphan rule.
This CL also contains significant changes to the UPB runtime so that both upb.rs and cpp.rs export a similar interface to simplify the implementation in map.rs and the generated code.
This CL does not yet implement the Proxied trait.
PiperOrigin-RevId: 582951914
This change moves almost everything in the `upb/` directory up one level, so
that for example `upb/upb/generated_code_support.h` becomes just
`upb/generated_code_support.h`. The only exceptions I made to this were that I
left `upb/cmake` and `upb/BUILD` where they are, mostly because that avoids
conflict with other files and the current locations seem reasonable for now.
The `python/` directory is a little bit of a challenge because we had to merge
the existing directory there with `upb/python/`. I made `upb/python/BUILD` into
the BUILD file for the merged directory, and it effectively loads the contents
of the other BUILD file via `python/build_targets.bzl`, but I plan to clean
this up soon.
PiperOrigin-RevId: 568651768
This adds `#![deny(unsafe_op_in_unsafe_fn)]` which removes the
implicit `unsafe` block that `unsafe fn` does.
It also adds many more `SAFETY` docs, corrects some incomplete
ones, and catches a null pointer returned by `upb_Arena_New`.
PiperOrigin-RevId: 549067106
In this CL I'd like to call existing C++ Protobuf API from the V0 Rust API. Since parts of the C++ API are defined inline and using (obviously) C++ name mangling, we need to create a "thunks.cc" file that:
1) Generates code for C++ API function we use from Rust
2) Exposes these functions without any name mangling (meaning using `extern "C"`)
In this CL we add Bazel logic to generate "thunks" file, compile it, and propagate its object to linking. We also add logic to protoc to generate this "thunks" file.
The protoc logic is rather rudimentary still. I hope to focus on protoc code quality in my followup work on V0 Rust API using C++ kernel.
PiperOrigin-RevId: 523479839