"""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("@upb//bazel:upb_proto_library.bzl", "UpbWrappedCcInfo", "upb_proto_library_aspect")
load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
proto_common = proto_common_do_not_use
visibility(["//rust/..."])
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,
is_upb):
"""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
is_upb (Bool): True when generating gencode for UPB, False otherwise.
Returns:
rs_outputs (([File], [File]): tuple(generated Rust files, generated C++ thunks).
"""
actions = ctx.actions
rs_outputs = proto_common.declare_generated_files(
actions = actions,
proto_info = proto_info,
extension = ".{}.pb.rs".format("u" if is_upb else "c"),
)
if is_upb:
cc_outputs = []
else:
cc_outputs = proto_common.declare_generated_files(
actions = actions,
proto_info = proto_info,
extension = ".pb.thunks.cc",
)
proto_common.compile(
actions = ctx.actions,
proto_info = proto_info,
generated_files = rs_outputs + cc_outputs,
proto_lang_toolchain_info = proto_lang_toolchain,
plugin_output = ctx.bin_dir.path,
)
return (rs_outputs, cc_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_cc(
ctx,
attr,
cc_toolchain,
feature_configuration,
src,
cc_infos):
"""Compiles a C++ source file.
Args:
ctx: The rule context.
attr: The current rule's attributes.
cc_toolchain: A cc_toolchain.
feature_configuration: A feature configuration.
src: The source file to be compiled.
cc_infos: List[CcInfo]: A list of CcInfo dependencies.
Returns:
A CcInfo provider.
"""
cc_info = cc_common.merge_cc_infos(direct_cc_infos = cc_infos)
(compilation_context, compilation_outputs) = cc_common.compile(
name = src.basename,
actions = ctx.actions,
feature_configuration = feature_configuration,
cc_toolchain = cc_toolchain,
srcs = [src],
grep_includes = ctx.file._grep_includes,
user_compile_flags = attr.copts if hasattr(attr, "copts") else [],
compilation_contexts = [cc_info.compilation_context],
)
(linking_context, _) = cc_common.create_linking_context_from_compilation_outputs(
name = src.basename,
actions = ctx.actions,
feature_configuration = feature_configuration,
cc_toolchain = cc_toolchain,
compilation_outputs = compilation_outputs,
linking_contexts = [cc_info.linking_context],
)
return CcInfo(
compilation_context = compilation_context,
linking_context = linking_context,
)
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]
cc_toolchain = find_cpp_toolchain(ctx)
feature_configuration = cc_common.configure_features(
ctx = ctx,
cc_toolchain = cc_toolchain,
requested_features = ctx.features,
unsupported_features = ctx.disabled_features,
)
(gencode, thunks) = _generate_rust_gencode(
ctx,
target[ProtoInfo],
proto_lang_toolchain,
is_upb,
)
if is_upb:
thunks_cc_info = target[UpbWrappedCcInfo].cc_info_with_thunks
else:
thunks_cc_info = cc_common.merge_cc_infos(cc_infos = [_compile_cc(
feature_configuration = feature_configuration,
src = thunk,
ctx = ctx,
attr = attr,
cc_toolchain = cc_toolchain,
cc_infos = [target[CcInfo], ctx.attr._cpp_thunks_deps[CcInfo]],
) for thunk in thunks])
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 = thunks_cc_info)
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",
),
"_cpp_thunks_deps": attr.label(
default = Label("//rust/cpp_kernel:cpp_api"),
),
"_grep_includes": attr.label(
allow_single_file = True,
default = Label("@bazel_tools//tools/cpp:grep-includes"),
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_rust_upb_toolchain" if is_upb else "//rust:proto_rust_cpp_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)