blob: aff4d2bec184fc98a216dc77d862c61488ba9c3d [file] [log] [blame]
# Protobuf Rust runtime packages.
load("@bazel_skylib//rules:common_settings.bzl", "string_flag")
load("@rules_rust//rust:defs.bzl", "rust_library", "rust_test")
load("//bazel/toolchains:proto_lang_toolchain.bzl", "proto_lang_toolchain")
package(
default_visibility = [
"//src/google/protobuf:__subpackages__",
],
)
licenses(["notice"])
# The current Rust Protobuf runtime for the build. Depending on the value of
# `:rust_proto_library_kernel` build setting it forwards to the cpp or upb kernels. This is the
# target that users are expected to depend on.
#
# Rust gencode (via `rust_upb_proto_library` and `rust_cc_proto_library`) doesn't depend on this
# target, instead, it depends on the kernel-specific libraries directly. The reason is that we need
# to be able to use both kernels in the same build. That allows us to have one TAP config for both
# kernels, and to run tests using a single Blaze invocation.
#
# WARNING: It's critical that users do not end up using Rust Protobufs with multiple kernels in
# their binaries. Currently this is achieved by using bzl visibility on kernel-specific rules.
# TODO: Hide the kernel-specific targets once we can restrict a target visibility to a
# rule.
rust_library(
name = "protobuf",
srcs = ["protobuf.rs"],
rustc_flags = select({
":use_upb_kernel": ["--cfg=upb_kernel"],
"//conditions:default": ["--cfg=cpp_kernel"],
}),
deps = select({
":use_upb_kernel": [":protobuf_upb"],
"//conditions:default": [":protobuf_cpp"],
}),
)
# This list contains kernel-agnostic logic and simple kernel-specific logic controlled by
# `#[cfg(...)]` attributes. That forces us to compile these files twice, once for each kernel. As a
# result these files are included in both `:protobuf_upb` and `:protobuf_cpp`.
# This is in principle identical to how we compile regular Rust source files twice
# (once for production, and once for unit testing).
#
# shared.rs is the root of the crate and has public items re-exported in protobuf.rs for user use.
PROTOBUF_SHARED = [
"enum.rs",
"internal.rs",
"primitive.rs",
"optional.rs",
"proxied.rs",
"repeated.rs",
"shared.rs",
"string.rs",
"map.rs",
"proto_macro.rs",
]
# The Rust Protobuf runtime using the upb kernel.
#
# `rust_upb_proto_library` implicitly depends on this target. This target cannot depend on
# `:rust_proto_library_kernel` build setting; it has to be fully functional under any value of that
# setting.
rust_library(
name = "protobuf_upb",
srcs = PROTOBUF_SHARED + ["upb.rs"],
crate_root = "shared.rs",
proc_macro_deps = [
"@crate_index//:paste",
],
rustc_flags = ["--cfg=upb_kernel"],
visibility = [
"//rust:__subpackages__",
"//src/google/protobuf:__subpackages__",
],
deps = [
":utf8",
"//rust/upb",
],
)
rust_test(
name = "protobuf_upb_test",
crate = ":protobuf_upb",
rustc_flags = [
"--cfg=upb_kernel",
],
deps = [
"@crate_index//:googletest",
],
)
# This provides an identical set of re-exports as `:protobuf` with `:use_upb_kernel` active.
# This is only used for tests shared between runtimes.
rust_library(
name = "protobuf_upb_export",
testonly = True,
srcs = ["protobuf.rs"],
rustc_flags = ["--cfg=upb_kernel"],
visibility = [
"//src/google/protobuf:__subpackages__",
],
deps = [":protobuf_upb"],
)
# The Rust Protobuf runtime using the cpp kernel.
#
# `rust_cpp_proto_library` implicitly depends on this target. This target cannot depend on
# `:rust_proto_library_kernel` build setting; it has to be fully functional under any value of that
# setting.
rust_library(
name = "protobuf_cpp",
srcs = PROTOBUF_SHARED + ["cpp.rs"],
crate_root = "shared.rs",
proc_macro_deps = [
"@crate_index//:paste",
],
rustc_flags = ["--cfg=cpp_kernel"],
deps = [
":utf8",
"//rust/cpp_kernel:cpp_api",
],
)
rust_test(
name = "protobuf_cpp_test",
crate = ":protobuf_cpp",
rustc_flags = [
"--cfg=cpp_kernel",
],
deps = [
"@crate_index//:googletest",
],
)
# This provides an identical set of re-exports as `:protobuf` with `:use_upb_kernel` inactive.
# This is only used for tests shared between runtimes.
rust_library(
name = "protobuf_cpp_export",
testonly = True,
srcs = ["protobuf.rs"],
rustc_flags = ["--cfg=cpp_kernel"],
visibility = [
"//src/google/protobuf:__subpackages__",
],
deps = [":protobuf_cpp"],
)
rust_library(
name = "utf8",
srcs = ["utf8.rs"],
visibility = ["//visibility:private"],
)
proto_lang_toolchain(
name = "proto_rust_upb_toolchain",
command_line = "--rust_out=$(OUT)",
progress_message = "Generating Rust proto_library %{label}",
runtime = ":protobuf_upb",
visibility = ["//visibility:public"],
)
proto_lang_toolchain(
name = "proto_rust_cpp_toolchain",
command_line = "--rust_out=$(OUT)",
progress_message = "Generating Rust proto_library %{label}",
runtime = ":protobuf_cpp",
visibility = ["//visibility:public"],
)
package_group(
name = "rust_proto_library_allowed_in_different_package",
packages = ["//rust/test"], # for unittest proto_libraries
)
# This flag controls what kernel all Rust Protobufs are using in the current build.
string_flag(
name = "rust_proto_library_kernel",
build_setting_default = "cpp",
values = [
"upb",
"cpp",
],
)
config_setting(
name = "use_upb_kernel",
flag_values = {
":rust_proto_library_kernel": "upb",
},
)