Add android_sdk_repo_host to build platform-tools&build-tools

The Android SDK has been built with Make up until now, monolithically,
then split up into several sdk-repo zip files for different purposes.
The Mac and Windows SDKs really only need to contain the platform-tools
and build-tools pieces, but due to this monolithic sdk zip, we had to
build the whole SDK first.

This adds an `android_sdk_repo_host` module that can build these
platform-tools and build-tools zips.

Bug: 187222815
Change-Id: I55809e1d7447dd65e22461f921b2b8abb6d5f822
diff --git a/android_sdk/sdk_repo_host.go b/android_sdk/sdk_repo_host.go
new file mode 100644
index 0000000..a76da8b
--- /dev/null
+++ b/android_sdk/sdk_repo_host.go
@@ -0,0 +1,295 @@
+// Copyright (C) 2021 The Android Open Source Project
+//
+// 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 android_sdk
+
+import (
+	"fmt"
+	"io"
+	"path/filepath"
+	"strings"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/pathtools"
+	"github.com/google/blueprint/proptools"
+
+	"android/soong/android"
+	"android/soong/cc/config"
+)
+
+var pctx = android.NewPackageContext("android/soong/android_sdk")
+
+func init() {
+	registerBuildComponents(android.InitRegistrationContext)
+}
+
+func registerBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("android_sdk_repo_host", SdkRepoHostFactory)
+}
+
+type sdkRepoHost struct {
+	android.ModuleBase
+	android.PackagingBase
+
+	properties sdkRepoHostProperties
+
+	outputBaseName string
+	outputFile     android.OptionalPath
+}
+
+type remapProperties struct {
+	From string
+	To   string
+}
+
+type sdkRepoHostProperties struct {
+	// The top level directory to use for the SDK repo.
+	Base_dir *string
+
+	// List of src:dst mappings to rename files from `deps`.
+	Deps_remap []remapProperties `android:"arch_variant"`
+
+	// List of zip files to merge into the SDK repo.
+	Merge_zips []string `android:"arch_variant,path"`
+
+	// List of sources to include into the SDK repo. These are usually raw files, filegroups,
+	// or genrules, as most built modules should be referenced via `deps`.
+	Srcs []string `android:"arch_variant,path"`
+
+	// List of files to strip. This should be a list of files, not modules. This happens after
+	// `deps_remap` and `merge_zips` are applied, but before the `base_dir` is added.
+	Strip_files []string `android:"arch_variant"`
+}
+
+// android_sdk_repo_host defines an Android SDK repo containing host tools.
+//
+// This implementation is trying to be a faithful reproduction of how these sdk-repos were produced
+// in the Make system, which may explain some of the oddities (like `strip_files` not being
+// automatic)
+func SdkRepoHostFactory() android.Module {
+	return newSdkRepoHostModule()
+}
+
+func newSdkRepoHostModule() *sdkRepoHost {
+	s := &sdkRepoHost{}
+	s.AddProperties(&s.properties)
+	android.InitPackageModule(s)
+	android.InitAndroidMultiTargetsArchModule(s, android.HostSupported, android.MultilibCommon)
+	return s
+}
+
+type dependencyTag struct {
+	blueprint.BaseDependencyTag
+	android.PackagingItemAlwaysDepTag
+}
+
+// TODO(b/201696252): Evaluate whether licenses should be propagated through this dependency.
+func (d dependencyTag) PropagateLicenses() bool {
+	return false
+}
+
+var depTag = dependencyTag{}
+
+func (s *sdkRepoHost) DepsMutator(ctx android.BottomUpMutatorContext) {
+	s.AddDeps(ctx, depTag)
+}
+
+func (s *sdkRepoHost) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	dir := android.PathForModuleOut(ctx, "zip")
+	builder := android.NewRuleBuilder(pctx, ctx).
+		Sbox(dir, android.PathForModuleOut(ctx, "out.sbox.textproto")).
+		SandboxInputs()
+
+	// Get files from modules listed in `deps`
+	packageSpecs := s.GatherPackagingSpecs(ctx)
+
+	// Handle `deps_remap` renames
+	err := remapPackageSpecs(packageSpecs, s.properties.Deps_remap)
+	if err != nil {
+		ctx.PropertyErrorf("deps_remap", "%s", err.Error())
+	}
+
+	s.CopySpecsToDir(ctx, builder, packageSpecs, dir)
+
+	// Collect licenses to write into NOTICE.txt
+	noticeMap := map[string]android.Paths{}
+	for path, pkgSpec := range packageSpecs {
+		licenseFiles := pkgSpec.EffectiveLicenseFiles()
+		if len(licenseFiles) > 0 {
+			noticeMap[path] = pkgSpec.EffectiveLicenseFiles()
+		}
+	}
+	notices := android.BuildNotices(ctx, noticeMap)
+	builder.Command().Text("cp").
+		Input(notices.TxtOutput.Path()).
+		Text(filepath.Join(dir.String(), "NOTICE.txt"))
+
+	// Handle `merge_zips` by extracting their contents into our tmpdir
+	for _, zip := range android.PathsForModuleSrc(ctx, s.properties.Merge_zips) {
+		builder.Command().
+			Text("unzip").
+			Flag("-DD").
+			Flag("-q").
+			FlagWithArg("-d ", dir.String()).
+			Input(zip)
+	}
+
+	// Copy files from `srcs` into our tmpdir
+	for _, src := range android.PathsForModuleSrc(ctx, s.properties.Srcs) {
+		builder.Command().
+			Text("cp").Input(src).Flag(dir.Join(ctx, src.Rel()).String())
+	}
+
+	// Handle `strip_files` by calling the necessary strip commands
+	//
+	// Note: this stripping logic was copied over from the old Make implementation
+	// It's not using the same flags as the regular stripping support, nor does it
+	// support the array of per-module stripping options. It would be nice if we
+	// pulled the stripped versions from the CC modules, but that doesn't exist
+	// for host tools today. (And not all the things we strip are CC modules today)
+	if ctx.Darwin() {
+		macStrip := config.MacStripPath(ctx)
+		for _, strip := range s.properties.Strip_files {
+			builder.Command().
+				Text(macStrip).Flag("-x").
+				Flag(dir.Join(ctx, strip).String())
+		}
+	} else {
+		llvmStrip := config.ClangPath(ctx, "bin/llvm-strip")
+		llvmLib := config.ClangPath(ctx, "lib64/libc++.so.1")
+		for _, strip := range s.properties.Strip_files {
+			cmd := builder.Command().Tool(llvmStrip).ImplicitTool(llvmLib)
+			if !ctx.Windows() {
+				cmd.Flag("-x")
+			}
+			cmd.Flag(dir.Join(ctx, strip).String())
+		}
+	}
+
+	// Fix up the line endings of all text files. This also removes executable permissions.
+	builder.Command().
+		Text("find").
+		Flag(dir.String()).
+		Flag("-name '*.aidl' -o -name '*.css' -o -name '*.html' -o -name '*.java'").
+		Flag("-o -name '*.js' -o -name '*.prop' -o -name '*.template'").
+		Flag("-o -name '*.txt' -o -name '*.windows' -o -name '*.xml' -print0").
+		// Using -n 500 for xargs to limit the max number of arguments per call to line_endings
+		// to 500. This avoids line_endings failing with "arguments too long".
+		Text("| xargs -0 -n 500 ").
+		BuiltTool("line_endings").
+		Flag("unix")
+
+	// Exclude some file types (roughly matching sdk.exclude.atree)
+	builder.Command().
+		Text("find").
+		Flag(dir.String()).
+		Flag("'('").
+		Flag("-name '.*' -o -name '*~' -o -name 'Makefile' -o -name 'Android.mk' -o").
+		Flag("-name '.*.swp' -o -name '.DS_Store' -o -name '*.pyc' -o -name 'OWNERS' -o").
+		Flag("-name 'MODULE_LICENSE_*' -o -name '*.ezt' -o -name 'Android.bp'").
+		Flag("')' -print0").
+		Text("| xargs -0 -r rm -rf")
+	builder.Command().
+		Text("find").
+		Flag(dir.String()).
+		Flag("-name '_*' ! -name '__*' -print0").
+		Text("| xargs -0 -r rm -rf")
+
+	if ctx.Windows() {
+		// Fix EOL chars to make window users happy
+		builder.Command().
+			Text("find").
+			Flag(dir.String()).
+			Flag("-maxdepth 2 -name '*.bat' -type f -print0").
+			Text("| xargs -0 -r unix2dos")
+	}
+
+	// Zip up our temporary directory as the sdk-repo
+	outputZipFile := dir.Join(ctx, "output.zip")
+	builder.Command().
+		BuiltTool("soong_zip").
+		FlagWithOutput("-o ", outputZipFile).
+		FlagWithArg("-P ", proptools.StringDefault(s.properties.Base_dir, ".")).
+		FlagWithArg("-C ", dir.String()).
+		FlagWithArg("-D ", dir.String())
+	builder.Command().Text("rm").Flag("-rf").Text(dir.String())
+
+	builder.Build("build_sdk_repo", "Creating sdk-repo-"+s.BaseModuleName())
+
+	osName := ctx.Os().String()
+	if osName == "linux_glibc" {
+		osName = "linux"
+	}
+	name := fmt.Sprintf("sdk-repo-%s-%s", osName, s.BaseModuleName())
+
+	s.outputBaseName = name
+	s.outputFile = android.OptionalPathForPath(outputZipFile)
+	ctx.InstallFile(android.PathForModuleInstall(ctx, "sdk-repo"), name+".zip", outputZipFile)
+}
+
+func (s *sdkRepoHost) AndroidMk() android.AndroidMkData {
+	return android.AndroidMkData{
+		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
+			// TODO: per-OS PHONY
+			fmt.Fprintln(w, ".PHONY:", name, "sdk_repo", "sdk-repo-"+name)
+			fmt.Fprintln(w, "sdk_repo", "sdk-repo-"+name+":", strings.Join(s.FilesToInstall().Strings(), " "))
+
+			fmt.Fprintf(w, "$(call dist-for-goals,sdk_repo sdk-repo-%s,%s:new_%s-$(FILE_NAME_TAG).zip)\n\n", s.BaseModuleName(), s.outputFile.String(), s.outputBaseName)
+		},
+	}
+}
+
+func remapPackageSpecs(specs map[string]android.PackagingSpec, remaps []remapProperties) error {
+	for _, remap := range remaps {
+		for path, spec := range specs {
+			if match, err := pathtools.Match(remap.From, path); err != nil {
+				return fmt.Errorf("Error parsing %q: %v", remap.From, err)
+			} else if match {
+				newPath := remap.To
+				if pathtools.IsGlob(remap.From) {
+					rel, err := filepath.Rel(constantPartOfPattern(remap.From), path)
+					if err != nil {
+						return fmt.Errorf("Error handling %q", path)
+					}
+					newPath = filepath.Join(remap.To, rel)
+				}
+				delete(specs, path)
+				spec.SetRelPathInPackage(newPath)
+				specs[newPath] = spec
+			}
+		}
+	}
+	return nil
+}
+
+func constantPartOfPattern(pattern string) string {
+	ret := ""
+	for pattern != "" {
+		var first string
+		first, pattern = splitFirst(pattern)
+		if pathtools.IsGlob(first) {
+			return ret
+		}
+		ret = filepath.Join(ret, first)
+	}
+	return ret
+}
+
+func splitFirst(path string) (string, string) {
+	i := strings.IndexRune(path, filepath.Separator)
+	if i < 0 {
+		return path, ""
+	}
+	return path[:i], path[i+1:]
+}