feat: adds a partial setup to build rust_icu_sys with bazel

This is an experimental change, hopefully will include other crates too.

MODULE.bazel

@@ -21,7 +21,6 @@ go_deps.from_file(go_mod = "//:go.mod")
 use_repo(go_deps)
 
 bazel_dep(name = "rules_foreign_cc", version = "0.10.1")
-
 bazel_dep(name = "toolchains_llvm", version = "1.0.0")
 
 # Configure and register the toolchain.
@@ -31,7 +30,6 @@ llvm.toolchain(
     # work with just any version of LLVM.
     llvm_version = "15.0.6",
 )
-
 use_repo(llvm, "llvm_toolchain")
 
 register_toolchains("@llvm_toolchain//:all")

WORKSPACE

@@ -1,59 +1,132 @@
 load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "rules_rust",
+    sha256 = "36ab8f9facae745c9c9c1b33d225623d976e78f2cc3f729b7973d8c20934ab95",
+    urls = ["https://github.com/bazelbuild/rules_rust/releases/download/0.31.0/rules_rust-v0.31.0.tar.gz"],
+)
+
+load("@rules_rust//rust:repositories.bzl", "rules_rust_dependencies", "rust_register_toolchains")
+
+rules_rust_dependencies()
+
+rust_register_toolchains(
+    edition = "2021",
+    versions = ["1.79.0"],
+)
+
+######################################################################
+
+# Use to generate rust-project.json.
+# Use bazel run @rules_rust//tools/rust_analyzer:gen_rust_project
+
+load(
+    "@rules_rust//tools/rust_analyzer:deps.bzl",
+    "rust_analyzer_dependencies",
+)
+
+rust_analyzer_dependencies()
+
+######################################################################
+
+# This is how to generate new lock files.  At the project outset, you must
+#   (1) create the empty files `//third_party/cargo:Cargo.lock`, and
+#       `//third_party/cargo:Cargo.Bazel.lock`.
+#   (2) Run `env CARGO_BAZEL_REPI=true bazel build //...` to initialize the
+#   lockfiles.
+load("@rules_rust//crate_universe:defs.bzl", "crate", "crates_repository", "render_config")
+
+crates_repository(
+    name = "crate_index",
+    cargo_lockfile = "//:Cargo.lock",
+    lockfile = "//:Cargo.Bazel.lock",
+    packages = {
+        # Add any other crates you need here.
+        "bumpalo": crate.spec(
+            version = "3.6.1",
+        ),
+        "libc": crate.spec(
+            version = "0.2.34",
+        ),
+        "paste": crate.spec(
+            version = "1.0",
+        ),
+        "anyhow": crate.spec(
+            version = "1.0.72",
+        ),
+        "bindgen": crate.spec(
+            version = "0.59.2",
+        ),
+        "lazy_static": crate.spec(
+            version = "1.4.0",
+        ),
+    },
+    render_config = render_config(
+        default_package_name = "",
+    ),
+)
+
+load("@crate_index//:defs.bzl", "crate_repositories")
+
+crate_repositories()
+
+######################################################################
 
 http_archive(
     name = "icu_74",
-    strip_prefix = "icu-release-74-2",
-    integrity = "sha256-J7hlCpTfb5Rcs7aGvjvjIMKjLt8+zimBZyv5i7O6qeE=",
     build_file = "//third_party/icu_74:icu.BUILD.bazel",
-    urls = [
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-74-2.tar.gz",
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-74-2.zip",
+    integrity = "sha256-J7hlCpTfb5Rcs7aGvjvjIMKjLt8+zimBZyv5i7O6qeE=",
+    patch_args = [
+        "-p1",
+        # Without this flag, the bazel build files just get emptied, but not
+        # removed. This is not enough.
+        "--remove-empty-files",
     ],
     patches = [
         # ICU has a nascent bazel build, which messes up our build based on
         # the configure_make rule from rules_foreign_cc. So we remove them.
         "//third_party/icu_74:0001-fix-removes-BUILD-files.patch",
     ],
-    patch_args = [
-        "-p1",
-        # Without this flag, the bazel build files just get emptied, but not
-        # removed. This is not enough.
-        "--remove-empty-files",
-    ]
+    strip_prefix = "icu-release-74-2",
+    urls = [
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-74-2.tar.gz",
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-74-2.zip",
+    ],
 )
 
 http_archive(
     name = "icu_73",
-    strip_prefix = "icu-release-73-1",
-    integrity = "sha256-57a1QMiB6D0kC0oSty+8l+9frTDY0A8u9nS6GOO/NkA=",
     build_file = "//third_party/icu_73:icu.BUILD.bazel",
-    urls = [
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-73-1.tar.gz",
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-73-1.zip",
+    integrity = "sha256-57a1QMiB6D0kC0oSty+8l+9frTDY0A8u9nS6GOO/NkA=",
+    patch_args = [
+        "-p1",
+        "--remove-empty-files",
     ],
     patches = [
         "//third_party/icu_73:0001-fix-removes-BUILD-files.patch",
     ],
-    patch_args = [
-        "-p1",
-        "--remove-empty-files",
-    ]
+    strip_prefix = "icu-release-73-1",
+    urls = [
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-73-1.tar.gz",
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-73-1.zip",
+    ],
 )
 
 http_archive(
     name = "icu_72",
-    strip_prefix = "icu-release-72-1",
-    integrity = "sha256-Q8utYo2Y83o/lfbDRXn5FE70veYCSPpgBKTwBtdIfmk=",
     build_file = "//third_party/icu_72:icu.BUILD.bazel",
-    urls = [
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-72-1.tar.gz",
-        "https://github.com/unicode-org/icu/archive/refs/tags/release-72-1.zip",
+    integrity = "sha256-Q8utYo2Y83o/lfbDRXn5FE70veYCSPpgBKTwBtdIfmk=",
+    patch_args = [
+        "-p1",
+        "--remove-empty-files",
     ],
     patches = [
         "//third_party/icu_72:0001-fix-removes-BUILD-files.patch",
     ],
-    patch_args = [
-        "-p1",
-        "--remove-empty-files",
-    ]
+    strip_prefix = "icu-release-72-1",
+    urls = [
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-72-1.tar.gz",
+        "https://github.com/unicode-org/icu/archive/refs/tags/release-72-1.zip",
+    ],
 )

rust_icu_sys/BUILD.bazel

@@ -0,0 +1,59 @@
+load("@crate_index//:defs.bzl", "aliases", "all_crate_deps")
+load("@rules_rust//rust:defs.bzl", "rust_library")
+load("@rules_rust//cargo:defs.bzl", "cargo_build_script")
+
+package(default_visibility = ["//visibility:public"])
+
+rust_library(
+    name = "rust_icu_sys",
+    srcs = [
+        "src/lib.rs",
+        "tests/hygiene.rs",
+        ":macros_rs",
+    ],
+    crate_name = "rust_icu_sys",
+    edition = "2021",
+    proc_macro_deps = [
+        "@crate_index//:paste",
+    ],
+    deps = [
+        "@crate_index//:libc",
+        ":build_script",
+        "@icu_74//:icu",
+    ],
+)
+
+cargo_build_script(
+    name = "build_script",
+    srcs = [ "build.rs" ],
+    crate_features = [
+        "use-bindgen", "bindgen", "renaming", "icu-config", "static",
+    ],
+    deps = [
+        "@crate_index//:anyhow",
+        "@crate_index//:bindgen",
+        "@crate_index//:lazy_static",
+    ],
+)
+
+filegroup(
+    name = "g1",
+    output_group = "streams",
+    srcs = [ ":build_script" ],
+)
+
+filegroup(
+    name = "g2",
+    output_group = "out_dir",
+    srcs = [ ":build_script" ],
+)
+
+genrule(
+    name = "macros_rs",
+    srcs = [
+        ":g2",
+    ],
+    cmd = "cp $</macros.rs $@",
+    outs = [ "macros.rs", ],
+
+)