blob: 23d841a187a66daeac769f959c077a1bfb75997d [file] [log] [blame]
"""This file implements an experimental, do-not-use-kind of rust_proto_library.
Disclaimer: This project is experimental, under heavy development, and should not
be used yet."""
load("@rules_rust//rust:defs.bzl", "rust_common")
load("//bazel/common:proto_common.bzl", "proto_common")
load("//bazel/common:proto_info.bzl", "ProtoInfo")
load(
"//rust:aspects.bzl",
"RustProtoInfo",
"label_to_crate_name",
"proto_rust_toolchain_label",
"rust_cc_proto_library_aspect",
"rust_upb_proto_library_aspect",
)
visibility([
"//experimental/...",
"//src/google/protobuf/...",
"//rust/...",
])
def rust_proto_library(name, deps, **args):
"""Declares all the boilerplate needed to use Rust protobufs conveniently.
Hopefully no user will ever need to read this code.
Args:
name: name of the Rust protobuf target.
deps: proto_library target for which to generate Rust gencode.
**args: other args passed to the rust_<kernel>_proto_library targets.
"""
if not name.endswith("_rust_proto"):
fail(
"{}: Name rust_proto_library target should end with `_rust_proto`, but was '{}'"
.format(name),
)
name = name.removesuffix("_rust_proto")
alias_args = {}
if "visibility" in args:
alias_args["visibility"] = args.pop("visibility")
native.alias(
name = name + "_rust_proto",
actual = select({
"//rust:use_upb_kernel": name + "_upb_rust_proto",
"//conditions:default": name + "_cpp_rust_proto",
}),
**alias_args
)
rust_upb_proto_library(
name = name + "_upb_rust_proto",
deps = deps,
visibility = ["//visibility:private"],
**args
)
rust_cc_proto_library(
name = name + "_cpp_rust_proto",
deps = deps,
visibility = ["//visibility:private"],
**args
)
def _user_visible_label(ctx):
label = str(ctx.label)
label = label.removesuffix("_cpp_rust_proto")
label = label.removesuffix("_upb_rust_proto")
return label + "_rust_proto"
def _rust_proto_library_impl(ctx):
if not ctx.label.name.endswith("_rust_proto"):
fail(
"{}: Name of rust_proto_library target should end with `_rust_proto`."
.format(_user_visible_label(ctx)),
)
deps = ctx.attr.deps
if not deps:
fail(
"{}: Exactly 1 dependency in `deps` attribute expected, none were provided."
.format(_user_visible_label(ctx)),
)
if len(deps) > 1:
fail(
"{}: Exactly 1 dependency in `deps` attribute expected, too many were provided."
.format(_user_visible_label(ctx)),
)
dep = deps[0]
rust_proto_info = dep[RustProtoInfo]
dep_variant_info = rust_proto_info.dep_variant_info
crate_info = dep_variant_info.crate_info
# Change the crate name from the hame of the proto_library to the name of the rust_proto_library.
#
# When the aspect visits proto_libraries, it doesn't know and cannot deduce the name of the
# rust_proto_library (although the name of rust_proto_libraries is consistently ending with
# _rust_proto, we can't rely on all proto_libraires to have a name consistently ending with
# _proto), therefore we have to modify it after the fact here.
#
# Since Starlark providers are frozen once they leave the _impl function that defines them,
# we have to create a shallow copy.
toolchain = ctx.toolchains["@rules_rust//rust:toolchain_type"]
fields = {field: getattr(crate_info, field) for field in dir(crate_info)}
pkg, name = _user_visible_label(ctx).rsplit(":")
label = struct(**{"name": name, "pkg": pkg})
fields["name"] = label_to_crate_name(ctx, label, toolchain)
crate_info_with_rust_proto_name = rust_common.crate_info(**fields)
return [
crate_info_with_rust_proto_name,
dep_variant_info.dep_info,
dep_variant_info.cc_info,
DefaultInfo(files = dep_variant_info.crate_info.srcs),
]
def _make_rust_proto_library(is_upb):
return rule(
implementation = _rust_proto_library_impl,
attrs = {
"deps": attr.label_list(
mandatory = True,
providers = [ProtoInfo],
aspects = [rust_upb_proto_library_aspect if is_upb else rust_cc_proto_library_aspect],
),
"_proto_lang_toolchain": attr.label(
default = Label(proto_rust_toolchain_label(is_upb)),
),
},
toolchains = [
"@rules_rust//rust:toolchain_type",
],
)
rust_upb_proto_library = _make_rust_proto_library(is_upb = True)
rust_cc_proto_library = _make_rust_proto_library(is_upb = False)