src/main/starlark/builtins_bzl/common/proto/proto_lang_toolchain.bzl - bazel - Git at Google

 # Copyright 2021 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
 #
 # Unless required by applicable law or agreed to in writing, software
 # distributed under the License is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.

 """A Starlark implementation of the proto_lang_toolchain rule."""

 load(":common/proto/proto_common.bzl", "ProtoLangToolchainInfo", "toolchains", proto_common = "proto_common_do_not_use")
 load(":common/proto/proto_info.bzl", "ProtoInfo")
 load(":common/proto/proto_semantics.bzl", "semantics")

 PackageSpecificationInfo = _builtins.toplevel.PackageSpecificationInfo

 def _rule_impl(ctx):
     provided_proto_sources = depset(transitive = [bp[ProtoInfo]._transitive_proto_sources for bp in ctx.attr.blacklisted_protos]).to_list()

     flag = ctx.attr.command_line
     if flag.find("$(PLUGIN_OUT)") > -1:
         fail("in attribute 'command_line': Placeholder '$(PLUGIN_OUT)' is not supported.")
     flag = flag.replace("$(OUT)", "%s")

     plugin = None
     if ctx.attr.plugin != None:
         plugin = ctx.attr.plugin[DefaultInfo].files_to_run

     if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION:
         proto_compiler = ctx.toolchains[semantics.PROTO_TOOLCHAIN].proto.proto_compiler
         protoc_opts = ctx.toolchains[semantics.PROTO_TOOLCHAIN].proto.protoc_opts
     else:
         proto_compiler = ctx.attr._proto_compiler.files_to_run
         protoc_opts = ctx.fragments.proto.experimental_protoc_opts

     if ctx.attr.protoc_minimal_do_not_use:
         proto_compiler = ctx.attr.protoc_minimal_do_not_use.files_to_run

     proto_lang_toolchain_info = ProtoLangToolchainInfo(
         out_replacement_format_flag = flag,
         output_files = ctx.attr.output_files,
         plugin_format_flag = ctx.attr.plugin_format_flag,
         plugin = plugin,
         runtime = ctx.attr.runtime,
         provided_proto_sources = provided_proto_sources,
         proto_compiler = proto_compiler,
         protoc_opts = protoc_opts,
         progress_message = ctx.attr.progress_message,
         mnemonic = ctx.attr.mnemonic,
         allowlist_different_package = ctx.attr.allowlist_different_package,
         toolchain_type = ctx.attr.toolchain_type.label if ctx.attr.toolchain_type else None,
     )
     return [
         DefaultInfo(files = depset(), runfiles = ctx.runfiles()),
         _builtins.toplevel.platform_common.ToolchainInfo(proto = proto_lang_toolchain_info),
         # TODO(b/300592942): remove when --incompatible_enable_proto_toolchains is flipped and removed
         proto_lang_toolchain_info,
     ]

 proto_lang_toolchain = rule(
     _rule_impl,
     doc = """
 <p>If using Bazel, please load the rule from <a href="https://github.com/bazelbuild/rules_proto">
 https://github.com/bazelbuild/rules_proto</a>.

 <p>Specifies how a LANG_proto_library rule (e.g., <code>java_proto_library</code>) should invoke the
 proto-compiler.
 Some LANG_proto_library rules allow specifying which toolchain to use using command-line flags;
 consult their documentation.

 <p>Normally you should not write those kind of rules unless you want to
 tune your Java compiler.

 <p>There's no compiler. The proto-compiler is taken from the proto_library rule we attach to. It is
 passed as a command-line flag to Blaze.
 Several features require a proto-compiler to be invoked on the proto_library rule itself.
 It's beneficial to enforce the compiler that LANG_proto_library uses is the same as the one
 <code>proto_library</code> does.

 <h4>Examples</h4>

 <p>A simple example would be:
 <pre><code class="lang-starlark">
 proto_lang_toolchain(
     name = "javalite_toolchain",
     command_line = "--javalite_out=shared,immutable:$(OUT)",
     plugin = ":javalite_plugin",
     runtime = ":protobuf_lite",
 )
 </code></pre>
     """,
     attrs = {
         "progress_message": attr.string(default = "Generating proto_library %{label}", doc = """
 This value will be set as the progress message on protoc action."""),
         "mnemonic": attr.string(default = "GenProto", doc = """
 This value will be set as the mnemonic on protoc action."""),
         "command_line": attr.string(mandatory = True, doc = """
 This value will be passed to proto-compiler to generate the code. Only include the parts
 specific to this code-generator/plugin (e.g., do not include -I parameters)
 <ul>
   <li><code>$(OUT)</code> is LANG_proto_library-specific. The rules are expected to define
       how they interpret this variable. For Java, for example, $(OUT) will be replaced with
       the src-jar filename to create.</li>
 </ul>"""),
         "output_files": attr.string(values = ["single", "multiple", "legacy"], default = "legacy", doc = """
 Controls how <code>$(OUT)</code> in <code>command_line</code> is formatted, either by
 a path to a single file or output directory in case of multiple files.
 Possible values are: "single", "multiple"."""),
         "plugin_format_flag": attr.string(doc = """
 If provided, this value will be passed to proto-compiler to use the plugin.
 The value must contain a single %s which is replaced with plugin executable.
 <code>--plugin=protoc-gen-PLUGIN=&lt;executable&gt;.</code>"""),
         "plugin": attr.label(
             executable = True,
             cfg = "exec",
             doc = """
 If provided, will be made available to the action that calls the proto-compiler, and will be
 passed to the proto-compiler:
 <code>--plugin=protoc-gen-PLUGIN=&lt;executable&gt;.</code>""",
         ),
         "runtime": attr.label(doc = """
 A language-specific library that the generated code is compiled against.
 The exact behavior is LANG_proto_library-specific.
 Java, for example, should compile against the runtime."""),
         "blacklisted_protos": attr.label_list(
             providers = [ProtoInfo],
             doc = """
 No code will be generated for files in the <code>srcs</code> attribute of
 <code>blacklisted_protos</code>.
 This is used for .proto files that are already linked into proto runtimes, such as
 <code>any.proto</code>.""",
         ),
         # TODO(b/311576642): add doc
         "allowlist_different_package": attr.label(
             default = semantics.allowlist_different_package,
             cfg = "exec",
             providers = [PackageSpecificationInfo],
         ),
         # TODO(b/311576642): add doc
         "toolchain_type": attr.label(),
         # DO NOT USE. For Protobuf incremental changes only: b/305068148.
         "protoc_minimal_do_not_use": attr.label(
             cfg = "exec",
             executable = True,
         ),
     } | ({} if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION else {
         "_proto_compiler": attr.label(
             cfg = "exec",
             executable = True,
             allow_files = True,
             default = configuration_field("proto", "proto_compiler"),
         ),
     }),
     provides = [ProtoLangToolchainInfo],
     fragments = ["proto"],
     toolchains = toolchains.use_toolchain(semantics.PROTO_TOOLCHAIN),  # Used to obtain protoc
 )
	# Copyright 2021 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
	#
	# Unless required by applicable law or agreed to in writing, software
	# distributed under the License is distributed on an "AS IS" BASIS,
	# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	# See the License for the specific language governing permissions and
	# limitations under the License.

	"""A Starlark implementation of the proto_lang_toolchain rule."""

	load(":common/proto/proto_common.bzl", "ProtoLangToolchainInfo", "toolchains", proto_common = "proto_common_do_not_use")
	load(":common/proto/proto_info.bzl", "ProtoInfo")
	load(":common/proto/proto_semantics.bzl", "semantics")

	PackageSpecificationInfo = _builtins.toplevel.PackageSpecificationInfo

	def _rule_impl(ctx):
	provided_proto_sources = depset(transitive = [bp[ProtoInfo]._transitive_proto_sources for bp in ctx.attr.blacklisted_protos]).to_list()

	flag = ctx.attr.command_line
	if flag.find("$(PLUGIN_OUT)") > -1:
	fail("in attribute 'command_line': Placeholder '$(PLUGIN_OUT)' is not supported.")
	flag = flag.replace("$(OUT)", "%s")

	plugin = None
	if ctx.attr.plugin != None:
	plugin = ctx.attr.plugin[DefaultInfo].files_to_run

	if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION:
	proto_compiler = ctx.toolchains[semantics.PROTO_TOOLCHAIN].proto.proto_compiler
	protoc_opts = ctx.toolchains[semantics.PROTO_TOOLCHAIN].proto.protoc_opts
	else:
	proto_compiler = ctx.attr._proto_compiler.files_to_run
	protoc_opts = ctx.fragments.proto.experimental_protoc_opts

	if ctx.attr.protoc_minimal_do_not_use:
	proto_compiler = ctx.attr.protoc_minimal_do_not_use.files_to_run

	proto_lang_toolchain_info = ProtoLangToolchainInfo(
	out_replacement_format_flag = flag,
	output_files = ctx.attr.output_files,
	plugin_format_flag = ctx.attr.plugin_format_flag,
	plugin = plugin,
	runtime = ctx.attr.runtime,
	provided_proto_sources = provided_proto_sources,
	proto_compiler = proto_compiler,
	protoc_opts = protoc_opts,
	progress_message = ctx.attr.progress_message,
	mnemonic = ctx.attr.mnemonic,
	allowlist_different_package = ctx.attr.allowlist_different_package,
	toolchain_type = ctx.attr.toolchain_type.label if ctx.attr.toolchain_type else None,
	)
	return [
	DefaultInfo(files = depset(), runfiles = ctx.runfiles()),
	_builtins.toplevel.platform_common.ToolchainInfo(proto = proto_lang_toolchain_info),
	# TODO(b/300592942): remove when --incompatible_enable_proto_toolchains is flipped and removed
	proto_lang_toolchain_info,
	]

	proto_lang_toolchain = rule(
	_rule_impl,
	doc = """
	<p>If using Bazel, please load the rule from <a href="https://github.com/bazelbuild/rules_proto">
	https://github.com/bazelbuild/rules_proto</a>.

	<p>Specifies how a LANG_proto_library rule (e.g., <code>java_proto_library</code>) should invoke the
	proto-compiler.
	Some LANG_proto_library rules allow specifying which toolchain to use using command-line flags;
	consult their documentation.

	<p>Normally you should not write those kind of rules unless you want to
	tune your Java compiler.

	<p>There's no compiler. The proto-compiler is taken from the proto_library rule we attach to. It is
	passed as a command-line flag to Blaze.
	Several features require a proto-compiler to be invoked on the proto_library rule itself.
	It's beneficial to enforce the compiler that LANG_proto_library uses is the same as the one
	<code>proto_library</code> does.

	<h4>Examples</h4>

	<p>A simple example would be:
	<pre><code class="lang-starlark">
	proto_lang_toolchain(
	name = "javalite_toolchain",
	command_line = "--javalite_out=shared,immutable:$(OUT)",
	plugin = ":javalite_plugin",
	runtime = ":protobuf_lite",
	)
	</code></pre>
	""",
	attrs = {
	"progress_message": attr.string(default = "Generating proto_library %{label}", doc = """
	This value will be set as the progress message on protoc action."""),
	"mnemonic": attr.string(default = "GenProto", doc = """
	This value will be set as the mnemonic on protoc action."""),
	"command_line": attr.string(mandatory = True, doc = """
	This value will be passed to proto-compiler to generate the code. Only include the parts
	specific to this code-generator/plugin (e.g., do not include -I parameters)
	<ul>
	<li><code>$(OUT)</code> is LANG_proto_library-specific. The rules are expected to define
	how they interpret this variable. For Java, for example, $(OUT) will be replaced with
	the src-jar filename to create.</li>
	</ul>"""),
	"output_files": attr.string(values = ["single", "multiple", "legacy"], default = "legacy", doc = """
	Controls how <code>$(OUT)</code> in <code>command_line</code> is formatted, either by
	a path to a single file or output directory in case of multiple files.
	Possible values are: "single", "multiple"."""),
	"plugin_format_flag": attr.string(doc = """
	If provided, this value will be passed to proto-compiler to use the plugin.
	The value must contain a single %s which is replaced with plugin executable.
	<code>--plugin=protoc-gen-PLUGIN=<executable>.</code>"""),
	"plugin": attr.label(
	executable = True,
	cfg = "exec",
	doc = """
	If provided, will be made available to the action that calls the proto-compiler, and will be
	passed to the proto-compiler:
	<code>--plugin=protoc-gen-PLUGIN=<executable>.</code>""",
	),
	"runtime": attr.label(doc = """
	A language-specific library that the generated code is compiled against.
	The exact behavior is LANG_proto_library-specific.
	Java, for example, should compile against the runtime."""),
	"blacklisted_protos": attr.label_list(
	providers = [ProtoInfo],
	doc = """
	No code will be generated for files in the <code>srcs</code> attribute of
	<code>blacklisted_protos</code>.
	This is used for .proto files that are already linked into proto runtimes, such as
	<code>any.proto</code>.""",
	),
	# TODO(b/311576642): add doc
	"allowlist_different_package": attr.label(
	default = semantics.allowlist_different_package,
	cfg = "exec",
	providers = [PackageSpecificationInfo],
	),
	# TODO(b/311576642): add doc
	"toolchain_type": attr.label(),
	# DO NOT USE. For Protobuf incremental changes only: b/305068148.
	"protoc_minimal_do_not_use": attr.label(
	cfg = "exec",
	executable = True,
	),
	} \| ({} if proto_common.INCOMPATIBLE_ENABLE_PROTO_TOOLCHAIN_RESOLUTION else {
	"_proto_compiler": attr.label(
	cfg = "exec",
	executable = True,
	allow_files = True,
	default = configuration_field("proto", "proto_compiler"),
	),
	}),
	provides = [ProtoLangToolchainInfo],
	fragments = ["proto"],
	toolchains = toolchains.use_toolchain(semantics.PROTO_TOOLCHAIN), # Used to obtain protoc
	)