cc/proto.go

// Copyright 2016 Google Inc. 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.

package cc

import (
	"github.com/google/blueprint/pathtools"
	"github.com/google/blueprint/proptools"

	"android/soong/android"
	"android/soong/bazel"
)

const (
	protoTypeDefault = "lite"
)

// genProto creates a rule to convert a .proto file to generated .pb.cc and .pb.h files and returns
// the paths to the generated files.
func genProto(ctx android.ModuleContext, protoFile android.Path, flags builderFlags) (cc, header android.WritablePath) {
	var ccFile, headerFile android.ModuleGenPath

	srcSuffix := ".cc"
	if flags.protoC {
		srcSuffix = ".c"
	}

	if flags.proto.CanonicalPathFromRoot {
		ccFile = android.GenPathWithExt(ctx, "proto", protoFile, "pb"+srcSuffix)
		headerFile = android.GenPathWithExt(ctx, "proto", protoFile, "pb.h")
	} else {
		rel := protoFile.Rel()
		ccFile = android.PathForModuleGen(ctx, "proto", pathtools.ReplaceExtension(rel, "pb"+srcSuffix))
		headerFile = android.PathForModuleGen(ctx, "proto", pathtools.ReplaceExtension(rel, "pb.h"))
	}

	protoDeps := flags.proto.Deps
	if flags.protoOptionsFile {
		optionsFile := pathtools.ReplaceExtension(protoFile.String(), "options")
		optionsPath := android.PathForSource(ctx, optionsFile)
		protoDeps = append(android.Paths{optionsPath}, protoDeps...)
	}

	outDir := flags.proto.Dir
	depFile := ccFile.ReplaceExtension(ctx, "d")
	outputs := android.WritablePaths{ccFile, headerFile}

	rule := android.NewRuleBuilder(pctx, ctx)

	android.ProtoRule(rule, protoFile, flags.proto, protoDeps, outDir, depFile, outputs)

	rule.Build("protoc_"+protoFile.Rel(), "protoc "+protoFile.Rel())

	return ccFile, headerFile
}

func protoDeps(ctx DepsContext, deps Deps, p *android.ProtoProperties, static bool) Deps {
	var lib string

	if String(p.Proto.Plugin) == "" {
		switch proptools.StringDefault(p.Proto.Type, protoTypeDefault) {
		case "full":
			if ctx.useSdk() {
				lib = "libprotobuf-cpp-full-ndk"
				static = true
			} else {
				lib = "libprotobuf-cpp-full"
			}
		case "lite":
			if ctx.useSdk() {
				lib = "libprotobuf-cpp-lite-ndk"
				static = true
			} else {
				lib = "libprotobuf-cpp-lite"
			}
		case "nanopb-c":
			lib = "libprotobuf-c-nano"
			static = true
		case "nanopb-c-enable_malloc":
			lib = "libprotobuf-c-nano-enable_malloc"
			static = true
		case "nanopb-c-16bit":
			lib = "libprotobuf-c-nano-16bit"
			static = true
		case "nanopb-c-enable_malloc-16bit":
			lib = "libprotobuf-c-nano-enable_malloc-16bit"
			static = true
		case "nanopb-c-32bit":
			lib = "libprotobuf-c-nano-32bit"
			static = true
		case "nanopb-c-enable_malloc-32bit":
			lib = "libprotobuf-c-nano-enable_malloc-32bit"
			static = true
		default:
			ctx.PropertyErrorf("proto.type", "unknown proto type %q",
				String(p.Proto.Type))
		}

		if static {
			deps.StaticLibs = append(deps.StaticLibs, lib)
			deps.ReexportStaticLibHeaders = append(deps.ReexportStaticLibHeaders, lib)
		} else {
			deps.SharedLibs = append(deps.SharedLibs, lib)
			deps.ReexportSharedLibHeaders = append(deps.ReexportSharedLibHeaders, lib)
		}
	}

	return deps
}

func protoFlags(ctx ModuleContext, flags Flags, p *android.ProtoProperties) Flags {
	flags.Local.CFlags = append(flags.Local.CFlags, "-DGOOGLE_PROTOBUF_NO_RTTI")

	flags.proto = android.GetProtoFlags(ctx, p)
	if flags.proto.CanonicalPathFromRoot {
		flags.Local.CommonFlags = append(flags.Local.CommonFlags, "-I"+flags.proto.SubDir.String())
	}
	flags.Local.CommonFlags = append(flags.Local.CommonFlags, "-I"+flags.proto.Dir.String())

	if String(p.Proto.Plugin) == "" {
		var plugin string

		switch String(p.Proto.Type) {
		case "nanopb-c", "nanopb-c-enable_malloc", "nanopb-c-16bit", "nanopb-c-enable_malloc-16bit", "nanopb-c-32bit", "nanopb-c-enable_malloc-32bit":
			flags.protoC = true
			flags.protoOptionsFile = true
			flags.proto.OutTypeFlag = "--nanopb_out"
			// Disable nanopb timestamps to support remote caching.
			flags.proto.OutParams = append(flags.proto.OutParams, "-T")
			plugin = "protoc-gen-nanopb"
		case "full":
			flags.proto.OutTypeFlag = "--cpp_out"
		case "lite":
			flags.proto.OutTypeFlag = "--cpp_out"
			flags.proto.OutParams = append(flags.proto.OutParams, "lite")
		case "":
			// TODO(b/119714316): this should be equivalent to "lite" in
			// order to match protoDeps, but some modules are depending on
			// this behavior
			flags.proto.OutTypeFlag = "--cpp_out"
		default:
			ctx.PropertyErrorf("proto.type", "unknown proto type %q",
				String(p.Proto.Type))
		}

		if plugin != "" {
			path := ctx.Config().HostToolPath(ctx, plugin)
			flags.proto.Deps = append(flags.proto.Deps, path)
			flags.proto.Flags = append(flags.proto.Flags, "--plugin="+path.String())
		}
	}

	return flags
}

type protoAttributes struct {
	Deps bazel.LabelListAttribute

	// A list of proto_library targets that that the proto_library in `deps` depends on
	// This list is overestimation.
	// Overestimation is necessary since Soong includes other protos via proto.include_dirs and not
	// a specific .proto file module explicitly.
	Transitive_deps bazel.LabelListAttribute

	// A list of cc_library_* targets that the generated cpp code depends on
	Cc_deps bazel.LabelListAttribute

	Min_sdk_version *string
}

type bp2buildProtoDeps struct {
	wholeStaticLib               *bazel.LabelAttribute
	implementationWholeStaticLib *bazel.LabelAttribute
	protoDep                     *bazel.LabelAttribute
}

func bp2buildProto(ctx android.Bp2buildMutatorContext, m *Module, protoSrcs bazel.LabelListAttribute, la linkerAttributes) bp2buildProtoDeps {
	var ret bp2buildProtoDeps

	protoInfo, ok := android.Bp2buildProtoProperties(ctx, &m.ModuleBase, protoSrcs)
	if !ok || protoInfo.Proto_libs.IsEmpty() {
		return ret
	}

	var depName string
	typ := proptools.StringDefault(protoInfo.Type, protoTypeDefault)
	var rule_class string
	suffix := "_cc_proto"
	switch typ {
	case "lite":
		suffix += "_lite"
		rule_class = "cc_lite_proto_library"
		depName = "libprotobuf-cpp-lite"
	case "full":
		rule_class = "cc_proto_library"
		depName = "libprotobuf-cpp-full"
	default:
		ctx.PropertyErrorf("proto.type", "cannot handle conversion at this time: %q", typ)
	}

	dep := android.BazelLabelForModuleDepSingle(ctx, depName)
	ret.protoDep = &bazel.LabelAttribute{Value: &dep}

	var protoAttrs protoAttributes
	protoAttrs.Deps.SetValue(protoInfo.Proto_libs)
	protoAttrs.Transitive_deps.SetValue(protoInfo.Transitive_proto_libs)

	// Add the implementation deps of the top-level cc_library_static
	// This is necessary to compile the internal root of cc_proto_library.
	// Without this, clang might not be able to find .h files that the generated cpp files depends on
	protoAttrs.Cc_deps = *la.implementationDeps.Clone()
	protoAttrs.Cc_deps.Append(la.implementationDynamicDeps)
	protoAttrs.Cc_deps.Append(la.implementationWholeArchiveDeps)
	protoAttrs.Cc_deps.Append(la.wholeArchiveDeps)
	// Subtract myself to prevent possible circular dep
	protoAttrs.Cc_deps = bazel.SubtractBazelLabelListAttribute(
		protoAttrs.Cc_deps,
		bazel.MakeLabelListAttribute(
			bazel.MakeLabelList([]bazel.Label{
				bazel.Label{Label: ":" + m.Name() + suffix},
			}),
		),
	)
	// Subtract the protobuf libraries since cc_proto_library implicitly adds them
	protoAttrs.Cc_deps = bazel.SubtractBazelLabelListAttribute(
		protoAttrs.Cc_deps,
		bazel.MakeLabelListAttribute(
			bazel.MakeLabelList([]bazel.Label{
				bazel.Label{Label: "//external/protobuf:libprotobuf-cpp-full", OriginalModuleName: "libprotobuf-cpp-full"},
				bazel.Label{Label: "//external/protobuf:libprotobuf-cpp-lite", OriginalModuleName: "libprotobuf-cpp-lite"},
			}),
		),
	)

	protoAttrs.Min_sdk_version = m.Properties.Min_sdk_version

	name := m.Name() + suffix
	tags := android.ApexAvailableTagsWithoutTestApexes(ctx, m)
	ctx.CreateBazelTargetModule(
		bazel.BazelTargetModuleProperties{
			Rule_class:        rule_class,
			Bzl_load_location: "//build/bazel/rules/cc:cc_proto.bzl",
		},
		android.CommonAttributes{Name: name, Tags: tags},
		&protoAttrs)

	var privateHdrs bool
	if lib, ok := m.linker.(*libraryDecorator); ok {
		privateHdrs = !proptools.Bool(lib.Properties.Proto.Export_proto_headers)
	}

	labelAttr := &bazel.LabelAttribute{Value: &bazel.Label{Label: ":" + name}}
	if privateHdrs {
		ret.implementationWholeStaticLib = labelAttr
	} else {
		ret.wholeStaticLib = labelAttr
	}

	return ret
}