Split upb_proto_library.bzl into its own .bzl file.

1 files changed, 291 insertions, 0 deletions

diff --git a/upb_proto_library.bzl b/upb_proto_library.bzl
new file mode 100644
index 0000000..962facd
--- /dev/null
+++ b/upb_proto_library.bzl
@@ -0,0 +1,291 @@
+"""Public rules for using upb protos:
+  - upb_proto_library()
+  - upb_proto_reflection_library()
+"""
+
+load("@bazel_skylib//lib:paths.bzl", "paths")
+load("@bazel_tools//tools/cpp:toolchain_utils.bzl", "find_cpp_toolchain")
+
+# copybara:strip_for_google3_begin
+load("@bazel_skylib//lib:versions.bzl", "versions")
+load("@bazel_version//:bazel_version.bzl", "bazel_version")
+# copybara:strip_end
+
+# Generic support code #########################################################
+
+_is_bazel = not hasattr(native, "genmpm")
+
+def _get_real_short_path(file):
+    # For some reason, files from other archives have short paths that look like:
+    #   ../com_google_protobuf/google/protobuf/descriptor.proto
+    short_path = file.short_path
+    if short_path.startswith("../"):
+        second_slash = short_path.index("/", 3)
+        short_path = short_path[second_slash + 1:]
+    return short_path
+
+def _get_real_root(file):
+    real_short_path = _get_real_short_path(file)
+    return file.path[:-len(real_short_path) - 1]
+
+def _get_real_roots(files):
+    roots = {}
+    for file in files:
+        real_root = _get_real_root(file)
+        if real_root:
+            roots[real_root] = True
+    return roots.keys()
+
+def _generate_output_file(ctx, src, extension):
+    if _is_bazel:
+        real_short_path = _get_real_short_path(src)
+    else:
+        real_short_path = paths.relativize(src.short_path, ctx.label.package)
+    output_filename = paths.replace_extension(real_short_path, extension)
+    ret = ctx.new_file(ctx.genfiles_dir, output_filename)
+    return ret
+
+def _filter_none(elems):
+    out = []
+    for elem in elems:
+        if elem:
+            out.append(elem)
+    return out
+
+def _cc_library_func(ctx, name, hdrs, srcs, dep_ccinfos):
+    """Like cc_library(), but callable from rules.
+
+    Args:
+      ctx: Rule context.
+      name: Unique name used to generate output files.
+      hdrs: Public headers that can be #included from other rules.
+      srcs: C/C++ source files.
+      dep_ccinfos: CcInfo providers of dependencies we should build/link against.
+
+    Returns:
+      CcInfo provider for this compilation.
+    """
+
+    compilation_contexts = [info.compilation_context for info in dep_ccinfos]
+    linking_contexts = [info.linking_context for info in dep_ccinfos]
+    toolchain = find_cpp_toolchain(ctx)
+    feature_configuration = cc_common.configure_features(
+        cc_toolchain = toolchain,
+        requested_features = ctx.features,
+        unsupported_features = ctx.disabled_features,
+    )
+
+    # copybara:strip_for_google3_begin
+    if bazel_version == "0.24.1":
+        # Compatibility code until gRPC is on 0.25.2 or later.
+        compilation_info = cc_common.compile(
+            ctx = ctx,
+            feature_configuration = feature_configuration,
+            cc_toolchain = toolchain,
+            srcs = srcs,
+            hdrs = hdrs,
+            compilation_contexts = compilation_contexts,
+        )
+        linking_info = cc_common.link(
+            ctx = ctx,
+            feature_configuration = feature_configuration,
+            cc_toolchain = toolchain,
+            cc_compilation_outputs = compilation_info.cc_compilation_outputs,
+            linking_contexts = linking_contexts,
+        )
+        return CcInfo(
+            compilation_context = compilation_info.compilation_context,
+            linking_context = linking_info.linking_context,
+        )
+
+    if not versions.is_at_least("0.25.2", bazel_version):
+        fail("upb requires Bazel >=0.25.2 or 0.24.1")
+
+    # copybara:strip_end
+
+    blaze_only_args = {}
+
+    if not _is_bazel:
+        blaze_only_args["grep_includes"] = ctx.file._grep_includes
+
+    (compilation_context, compilation_outputs) = cc_common.compile(
+        actions = ctx.actions,
+        feature_configuration = feature_configuration,
+        cc_toolchain = toolchain,
+        name = name,
+        srcs = srcs,
+        public_hdrs = hdrs,
+        compilation_contexts = compilation_contexts,
+        **blaze_only_args
+    )
+    (linking_context, linking_outputs) = cc_common.create_linking_context_from_compilation_outputs(
+        actions = ctx.actions,
+        name = name,
+        feature_configuration = feature_configuration,
+        cc_toolchain = toolchain,
+        compilation_outputs = compilation_outputs,
+        linking_contexts = linking_contexts,
+        **blaze_only_args
+    )
+
+    return CcInfo(
+        compilation_context = compilation_context,
+        linking_context = linking_context,
+    )
+
+# upb_proto_library / upb_proto_reflection_library shared code #################
+
+GeneratedSrcs = provider(
+    fields = {
+        "srcs": "list of srcs",
+        "hdrs": "list of hdrs",
+    },
+)
+
+_WrappedCcInfo = provider(fields = ["cc_info"])
+_WrappedGeneratedSrcs = provider(fields = ["srcs"])
+
+def _compile_upb_protos(ctx, proto_info, proto_sources, ext):
+    srcs = [_generate_output_file(ctx, name, ext + ".c") for name in proto_sources]
+    hdrs = [_generate_output_file(ctx, name, ext + ".h") for name in proto_sources]
+    transitive_sets = list(proto_info.transitive_descriptor_sets)
+    ctx.actions.run(
+        inputs = depset(
+            direct = [ctx.executable._upbc, proto_info.direct_descriptor_set],
+            transitive = [proto_info.transitive_descriptor_sets],
+        ),
+        outputs = srcs + hdrs,
+        executable = ctx.executable._protoc,
+        arguments = [
+                        "--upb_out=" + _get_real_root(srcs[0]),
+                        "--plugin=protoc-gen-upb=" + ctx.executable._upbc.path,
+                        "--descriptor_set_in=" + ":".join([f.path for f in transitive_sets]),
+                    ] +
+                    [_get_real_short_path(file) for file in proto_sources],
+        progress_message = "Generating upb protos for :" + ctx.label.name,
+    )
+    return GeneratedSrcs(srcs = srcs, hdrs = hdrs)
+
+def _upb_proto_rule_impl(ctx):
+    if len(ctx.attr.deps) != 1:
+        fail("only one deps dependency allowed.")
+    dep = ctx.attr.deps[0]
+    if _WrappedCcInfo not in dep or _WrappedGeneratedSrcs not in dep:
+        fail("proto_library rule must generate _WrappedCcInfo and " +
+             "_WrappedGeneratedSrcs (aspect should have handled this).")
+    cc_info = dep[_WrappedCcInfo].cc_info
+    srcs = dep[_WrappedGeneratedSrcs].srcs
+    lib = cc_info.linking_context.libraries_to_link[0]
+    files = _filter_none([
+        lib.static_library,
+        lib.pic_static_library,
+        lib.dynamic_library,
+    ])
+    return [
+        DefaultInfo(files = depset(files + srcs.hdrs + srcs.srcs)),
+        srcs,
+        cc_info,
+    ]
+
+def _upb_proto_aspect_impl(target, ctx):
+    proto_info = target[ProtoInfo]
+    files = _compile_upb_protos(ctx, proto_info, proto_info.direct_sources, ctx.attr._ext)
+    deps = ctx.rule.attr.deps + ctx.attr._upb
+    dep_ccinfos = [dep[CcInfo] for dep in deps if CcInfo in dep]
+    dep_ccinfos += [dep[_WrappedCcInfo].cc_info for dep in deps if _WrappedCcInfo in dep]
+    cc_info = _cc_library_func(
+        ctx = ctx,
+        name = ctx.rule.attr.name + ctx.attr._ext,
+        hdrs = files.hdrs,
+        srcs = files.srcs,
+        dep_ccinfos = dep_ccinfos,
+    )
+    return [_WrappedCcInfo(cc_info = cc_info), _WrappedGeneratedSrcs(srcs = files)]
+
+def _maybe_add(d):
+    if not _is_bazel:
+        d["_grep_includes"] = attr.label(
+            allow_single_file = True,
+            cfg = "host",
+            default = "//tools/cpp:grep-includes",
+        )
+    return d
+
+# upb_proto_library() ##########################################################
+
+_upb_proto_library_aspect = aspect(
+    attrs = _maybe_add({
+        "_upbc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = ":protoc-gen-upb",
+        ),
+        "_protoc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = "@com_google_protobuf//:protoc",
+        ),
+        "_cc_toolchain": attr.label(
+            default = "@bazel_tools//tools/cpp:current_cc_toolchain",
+        ),
+        "_upb": attr.label_list(default = [":upb"]),
+        "_ext": attr.string(default = ".upb"),
+    }),
+    implementation = _upb_proto_aspect_impl,
+    attr_aspects = ["deps"],
+    fragments = ["cpp"],
+)
+
+upb_proto_library = rule(
+    output_to_genfiles = True,
+    implementation = _upb_proto_rule_impl,
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [_upb_proto_library_aspect],
+            allow_rules = ["proto_library"],
+            providers = [ProtoInfo],
+        ),
+    },
+)
+
+# upb_proto_reflection_library() ###############################################
+
+_upb_proto_reflection_library_aspect = aspect(
+    attrs = _maybe_add({
+        "_upbc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = ":protoc-gen-upb",
+        ),
+        "_protoc": attr.label(
+            executable = True,
+            cfg = "host",
+            default = "@com_google_protobuf//:protoc",
+        ),
+        "_cc_toolchain": attr.label(
+            default = "@bazel_tools//tools/cpp:current_cc_toolchain",
+        ),
+        "_upb": attr.label_list(
+            default = [
+                ":upb",
+                ":reflection",
+            ],
+        ),
+        "_ext": attr.string(default = ".upbdefs"),
+    }),
+    implementation = _upb_proto_aspect_impl,
+    attr_aspects = ["deps"],
+    fragments = ["cpp"],
+)
+
+upb_proto_reflection_library = rule(
+    output_to_genfiles = True,
+    implementation = _upb_proto_rule_impl,
+    attrs = {
+        "deps": attr.label_list(
+            aspects = [_upb_proto_reflection_library_aspect],
+            allow_rules = ["proto_library"],
+            providers = [ProtoInfo],
+        ),
+    },
+)