"""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.""" # buildifier: disable=bzl-visibility load("@rules_rust//rust/private:providers.bzl", "CrateInfo", "DepInfo", "DepVariantInfo") # buildifier: disable=bzl-visibility load("@rules_rust//rust/private:rustc.bzl", "rustc_compile_action") load("@rules_rust//rust:defs.bzl", "rust_common") load("//third_party/upb/bazel:upb_proto_library.bzl", "UpbWrappedCcInfo", "upb_proto_library_aspect") proto_common = proto_common_do_not_use RustProtoInfo = provider( doc = "Rust protobuf provider info", fields = { "dep_variant_info": "DepVariantInfo for the compiled Rust gencode (also covers its " + "transitive dependencies)", }, ) def _generate_rust_gencode( ctx, proto_info, proto_lang_toolchain): """Generates Rust gencode This function uses proto_common APIs and a ProtoLangToolchain to register an action that invokes protoc with the right flags. Args: ctx (RuleContext): current rule context proto_info (ProtoInfo): ProtoInfo of the proto_library target for which we are generating gencode proto_lang_toolchain (ProtoLangToolchainInfo): proto lang toolchain for Rust Returns: rs_outputs ([File]): generated Rust source files """ actions = ctx.actions rs_outputs = proto_common.declare_generated_files( actions = actions, proto_info = proto_info, extension = ".pb.rs", ) proto_common.compile( actions = ctx.actions, proto_info = proto_info, generated_files = rs_outputs, proto_lang_toolchain_info = proto_lang_toolchain, plugin_output = ctx.bin_dir.path, ) return rs_outputs def _get_crate_info(providers): for provider in providers: if hasattr(provider, "name"): return provider fail("Couldn't find a CrateInfo in the list of providers") def _get_dep_info(providers): for provider in providers: if hasattr(provider, "direct_crates"): return provider fail("Couldn't find a DepInfo in the list of providers") def _get_cc_info(providers): for provider in providers: if hasattr(provider, "linking_context"): return provider fail("Couldn't find a CcInfo in the list of providers") def _compile_rust(ctx, attr, src, extra_srcs, deps): """Compiles a Rust source file. Eventually this function could be upstreamed into rules_rust and be made present in rust_common. Args: ctx (RuleContext): The rule context. attr (Attrs): The current rule's attributes (`ctx.attr` for rules, `ctx.rule.attr` for aspects) src (File): The crate root source file to be compiled. extra_srcs ([File]): Additional source files to include in the crate. deps (List[DepVariantInfo]): A list of dependencies needed. Returns: A DepVariantInfo provider. """ toolchain = ctx.toolchains["@rules_rust//rust:toolchain"] output_hash = repr(hash(src.path)) # TODO(b/270124215): Use the import! macro once available crate_name = ctx.label.name.replace("-", "_") lib_name = "{prefix}{name}-{lib_hash}{extension}".format( prefix = "lib", name = crate_name, lib_hash = output_hash, extension = ".rlib", ) rmeta_name = "{prefix}{name}-{lib_hash}{extension}".format( prefix = "lib", name = crate_name, lib_hash = output_hash, extension = ".rmeta", ) lib = ctx.actions.declare_file(lib_name) rmeta = ctx.actions.declare_file(rmeta_name) providers = rustc_compile_action( ctx = ctx, attr = attr, toolchain = toolchain, crate_info = rust_common.create_crate_info( name = crate_name, type = "rlib", root = src, srcs = depset([src] + extra_srcs), deps = depset(deps), proc_macro_deps = depset([]), aliases = {}, output = lib, metadata = rmeta, edition = "2021", is_test = False, rustc_env = {}, compile_data = depset([]), compile_data_targets = depset([]), owner = ctx.label, ), output_hash = output_hash, ) return DepVariantInfo( crate_info = _get_crate_info(providers), dep_info = _get_dep_info(providers), cc_info = _get_cc_info(providers), build_info = None, ) def _is_cc_proto_library(rule): """Detects if the current rule is a cc_proto_library.""" return rule.kind == "cc_proto_library" def _rust_upb_proto_aspect_impl(target, ctx): """Implements the Rust protobuf aspect logic for UPB kernel.""" return _rust_proto_aspect_common(target, ctx, is_upb = True) def _rust_cc_proto_aspect_impl(target, ctx): """Implements the Rust protobuf aspect logic for C++ kernel.""" return _rust_proto_aspect_common(target, ctx, is_upb = False) def _rust_proto_aspect_common(target, ctx, is_upb): if RustProtoInfo in target: return [] if _is_cc_proto_library(ctx.rule): # This is cc_proto_library, but we need the RustProtoInfo provider of the proto_library that # this aspect provides. Luckily this aspect has already been attached on the proto_library # so we can just read the provider. return [ctx.rule.attr.deps[0][RustProtoInfo]] proto_lang_toolchain = ctx.attr._proto_lang_toolchain[proto_common.ProtoLangToolchainInfo] gencode = _generate_rust_gencode(ctx, target[ProtoInfo], proto_lang_toolchain) runtime = proto_lang_toolchain.runtime dep_variant_info_for_runtime = DepVariantInfo( crate_info = runtime[CrateInfo] if CrateInfo in runtime else None, dep_info = runtime[DepInfo] if DepInfo in runtime else None, cc_info = runtime[CcInfo] if CcInfo in runtime else None, build_info = None, ) dep_variant_info_for_native_gencode = DepVariantInfo( cc_info = target[UpbWrappedCcInfo].cc_info_with_thunks if is_upb else target[CcInfo], ) proto_dep = getattr(ctx.rule.attr, "deps", []) dep_variant_info = _compile_rust( ctx = ctx, attr = ctx.rule.attr, src = gencode[0], extra_srcs = gencode[1:], deps = [dep_variant_info_for_runtime, dep_variant_info_for_native_gencode] + ( [proto_dep[0][RustProtoInfo].dep_variant_info] if proto_dep else [] ), ) return [RustProtoInfo(dep_variant_info = dep_variant_info)] def _make_proto_library_aspect(is_upb): return aspect( implementation = (_rust_upb_proto_aspect_impl if is_upb else _rust_cc_proto_aspect_impl), attr_aspects = ["deps"], # Since we can reference upb_proto_library_aspect by name, we can just ask Bazel to attach # it here. requires = ([upb_proto_library_aspect] if is_upb else []), required_aspect_providers = ([] if is_upb else [CcInfo]), attrs = { "_cc_toolchain": attr.label( doc = ( "In order to use find_cc_toolchain, your rule has to depend " + "on C++ toolchain. See `@rules_cc//cc:find_cc_toolchain.bzl` " + "docs for details." ), default = Label("@bazel_tools//tools/cpp:current_cc_toolchain"), ), "_collect_cc_coverage": attr.label( default = Label("@rules_rust//util:collect_coverage"), executable = True, cfg = "exec", ), "_error_format": attr.label( default = Label("@rules_rust//:error_format"), ), "_extra_exec_rustc_flag": attr.label( default = Label("@rules_rust//:extra_exec_rustc_flag"), ), "_extra_exec_rustc_flags": attr.label( default = Label("@rules_rust//:extra_exec_rustc_flags"), ), "_extra_rustc_flag": attr.label( default = Label("@rules_rust//:extra_rustc_flag"), ), "_extra_rustc_flags": attr.label( default = Label("@rules_rust//:extra_rustc_flags"), ), "_process_wrapper": attr.label( doc = "A process wrapper for running rustc on all platforms.", default = Label("@rules_rust//util/process_wrapper"), executable = True, allow_single_file = True, cfg = "exec", ), "_proto_lang_toolchain": attr.label( default = Label("//rust:proto_lang_toolchain"), ), }, fragments = ["cpp"], host_fragments = ["cpp"], toolchains = [ str(Label("@rules_rust//rust:toolchain")), "@bazel_tools//tools/cpp:toolchain_type", ], incompatible_use_toolchain_transition = True, ) rust_upb_proto_library_aspect = _make_proto_library_aspect(is_upb = True) rust_cc_proto_library_aspect = _make_proto_library_aspect(is_upb = False)