rules/native_binary.bzl

# Copyright 2019 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
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# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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"""native_binary() and native_test() rule implementations.

These rules let you wrap a pre-built binary or script in a conventional binary
and test rule respectively. They fulfill the same goal as sh_binary and sh_test
do, but they run the wrapped binary directly, instead of through Bash, so they
don't depend on Bash and work with --shell_exectuable="".
"""

load("//rules/private:copy_file_private.bzl", "copy_bash", "copy_cmd")

def _impl_rule(ctx, is_windows):
    out = ctx.actions.declare_file(ctx.attr.out)
    if is_windows:
        copy_cmd(ctx, ctx.file.src, out)
    else:
        copy_bash(ctx, ctx.file.src, out)
    runfiles = ctx.runfiles(files = ctx.files.data)

    # Bazel 4.x LTS does not support `merge_all`.
    # TODO: remove `merge` branch once we drop support for Bazel 4.x.
    if hasattr(runfiles, "merge_all"):
        runfiles = runfiles.merge_all([
            d[DefaultInfo].default_runfiles
            for d in ctx.attr.data + [ctx.attr.src]
        ])
    else:
        for d in ctx.attr.data:
            runfiles = runfiles.merge(d[DefaultInfo].default_runfiles)
        runfiles = runfiles.merge(ctx.attr.src[DefaultInfo].default_runfiles)

    return DefaultInfo(
        executable = out,
        files = depset([out]),
        runfiles = runfiles,
    )

def _impl(ctx):
    return _impl_rule(ctx, ctx.attr.is_windows)

_ATTRS = {
    "src": attr.label(
        executable = True,
        allow_single_file = True,
        mandatory = True,
        cfg = "host",
    ),
    "data": attr.label_list(allow_files = True),
    # "out" is attr.string instead of attr.output, so that it is select()'able.
    "out": attr.string(mandatory = True),
    "is_windows": attr.bool(mandatory = True),
}

_native_binary = rule(
    implementation = _impl,
    attrs = _ATTRS,
    executable = True,
)

_native_test = rule(
    implementation = _impl,
    attrs = _ATTRS,
    test = True,
)

def native_binary(name, src, out, data = None, **kwargs):
    """Wraps a pre-built binary or script with a binary rule.

    You can "bazel run" this rule like any other binary rule, and use it as a tool in genrule.tools for example. You can also augment the binary with runfiles.

    Args:
      name: The name of the rule.
      src: label; path of the pre-built executable
      out: output; an output name for the copy of the binary. (Bazel requires that this rule make a copy of 'src'.)
      data: list of labels; data dependencies
      **kwargs: The <a href="https://docs.bazel.build/versions/main/be/common-definitions.html#common-attributes-binaries">common attributes for binaries</a>.
    """
    _native_binary(
        name = name,
        src = src,
        out = out,
        data = data,
        is_windows = select({
            "@bazel_tools//src/conditions:host_windows": True,
            "//conditions:default": False,
        }),
        **kwargs
    )

def native_test(name, src, out, data = None, **kwargs):
    """Wraps a pre-built binary or script with a test rule.

    You can "bazel test" this rule like any other test rule. You can also augment the binary with
    runfiles.

    Args:
      name: The name of the test rule.
      src: label; path of the pre-built executable
      out: output; an output name for the copy of the binary. (Bazel requires that this rule make a copy of 'src'.)
      data: list of labels; data dependencies
      **kwargs: The <a href="https://docs.bazel.build/versions/main/be/common-definitions.html#common-attributes-tests">common attributes for tests</a>.
    """
    _native_test(
        name = name,
        src = src,
        out = out,
        data = data,
        is_windows = select({
            "@bazel_tools//src/conditions:host_windows": True,
            "//conditions:default": False,
        }),
        **kwargs
    )