apex/apex.go

// Copyright (C) 2018 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 apex

import (
	"fmt"
	"io"
	"path/filepath"
	"runtime"
	"sort"
	"strings"

	"android/soong/android"
	"android/soong/cc"
	"android/soong/java"
	"android/soong/python"

	"github.com/google/blueprint"
	"github.com/google/blueprint/bootstrap"
	"github.com/google/blueprint/proptools"
)

var (
	pctx = android.NewPackageContext("android/apex")

	// Create a canned fs config file where all files and directories are
	// by default set to (uid/gid/mode) = (1000/1000/0644)
	// TODO(b/113082813) make this configurable using config.fs syntax
	generateFsConfig = pctx.StaticRule("generateFsConfig", blueprint.RuleParams{
		Command: `echo '/ 1000 1000 0755' > ${out} && ` +
			`echo '/apex_manifest.json 1000 1000 0644' >> ${out} && ` +
			`echo ${ro_paths} | tr ' ' '\n' | awk '{print "/"$$1 " 1000 1000 0644"}' >> ${out} && ` +
			`echo ${exec_paths} | tr ' ' '\n' | awk '{print "/"$$1 " 0 2000 0755"}' >> ${out}`,
		Description: "fs_config ${out}",
	}, "ro_paths", "exec_paths")

	// TODO(b/113233103): make sure that file_contexts is sane, i.e., validate
	// against the binary policy using sefcontext_compiler -p <policy>.

	// TODO(b/114327326): automate the generation of file_contexts
	apexRule = pctx.StaticRule("apexRule", blueprint.RuleParams{
		Command: `rm -rf ${image_dir} && mkdir -p ${image_dir} && ` +
			`(${copy_commands}) && ` +
			`APEXER_TOOL_PATH=${tool_path} ` +
			`${apexer} --force --manifest ${manifest} ` +
			`--file_contexts ${file_contexts} ` +
			`--canned_fs_config ${canned_fs_config} ` +
			`--payload_type image ` +
			`--key ${key} ${opt_flags} ${image_dir} ${out} `,
		CommandDeps: []string{"${apexer}", "${avbtool}", "${e2fsdroid}", "${merge_zips}",
			"${mke2fs}", "${resize2fs}", "${sefcontext_compile}",
			"${soong_zip}", "${zipalign}", "${aapt2}", "prebuilts/sdk/current/public/android.jar"},
		Description: "APEX ${image_dir} => ${out}",
	}, "tool_path", "image_dir", "copy_commands", "manifest", "file_contexts", "canned_fs_config", "key", "opt_flags")

	zipApexRule = pctx.StaticRule("zipApexRule", blueprint.RuleParams{
		Command: `rm -rf ${image_dir} && mkdir -p ${image_dir} && ` +
			`(${copy_commands}) && ` +
			`APEXER_TOOL_PATH=${tool_path} ` +
			`${apexer} --force --manifest ${manifest} ` +
			`--payload_type zip ` +
			`${image_dir} ${out} `,
		CommandDeps: []string{"${apexer}", "${merge_zips}", "${soong_zip}", "${zipalign}", "${aapt2}"},
		Description: "ZipAPEX ${image_dir} => ${out}",
	}, "tool_path", "image_dir", "copy_commands", "manifest")

	apexProtoConvertRule = pctx.AndroidStaticRule("apexProtoConvertRule",
		blueprint.RuleParams{
			Command:     `${aapt2} convert --output-format proto $in -o $out`,
			CommandDeps: []string{"${aapt2}"},
		})

	apexBundleRule = pctx.StaticRule("apexBundleRule", blueprint.RuleParams{
		Command: `${zip2zip} -i $in -o $out ` +
			`apex_payload.img:apex/${abi}.img ` +
			`apex_manifest.json:root/apex_manifest.json ` +
			`AndroidManifest.xml:manifest/AndroidManifest.xml`,
		CommandDeps: []string{"${zip2zip}"},
		Description: "app bundle",
	}, "abi")
)

var imageApexSuffix = ".apex"
var zipApexSuffix = ".zipapex"

var imageApexType = "image"
var zipApexType = "zip"

type dependencyTag struct {
	blueprint.BaseDependencyTag
	name string
}

var (
	sharedLibTag   = dependencyTag{name: "sharedLib"}
	executableTag  = dependencyTag{name: "executable"}
	javaLibTag     = dependencyTag{name: "javaLib"}
	prebuiltTag    = dependencyTag{name: "prebuilt"}
	keyTag         = dependencyTag{name: "key"}
	certificateTag = dependencyTag{name: "certificate"}
)

func init() {
	pctx.Import("android/soong/android")
	pctx.Import("android/soong/java")
	pctx.HostBinToolVariable("apexer", "apexer")
	// ART minimal builds (using the master-art manifest) do not have the "frameworks/base"
	// projects, and hence cannot built 'aapt2'. Use the SDK prebuilt instead.
	hostBinToolVariableWithPrebuilt := func(name, prebuiltDir, tool string) {
		pctx.VariableFunc(name, func(ctx android.PackageVarContext) string {
			if !ctx.Config().FrameworksBaseDirExists(ctx) {
				return filepath.Join(prebuiltDir, runtime.GOOS, "bin", tool)
			} else {
				return pctx.HostBinToolPath(ctx, tool).String()
			}
		})
	}
	hostBinToolVariableWithPrebuilt("aapt2", "prebuilts/sdk/tools", "aapt2")
	pctx.HostBinToolVariable("avbtool", "avbtool")
	pctx.HostBinToolVariable("e2fsdroid", "e2fsdroid")
	pctx.HostBinToolVariable("merge_zips", "merge_zips")
	pctx.HostBinToolVariable("mke2fs", "mke2fs")
	pctx.HostBinToolVariable("resize2fs", "resize2fs")
	pctx.HostBinToolVariable("sefcontext_compile", "sefcontext_compile")
	pctx.HostBinToolVariable("soong_zip", "soong_zip")
	pctx.HostBinToolVariable("zip2zip", "zip2zip")
	pctx.HostBinToolVariable("zipalign", "zipalign")

	android.RegisterModuleType("apex", apexBundleFactory)
	android.RegisterModuleType("apex_test", testApexBundleFactory)
	android.RegisterModuleType("apex_defaults", defaultsFactory)
	android.RegisterModuleType("prebuilt_apex", PrebuiltFactory)

	android.PostDepsMutators(func(ctx android.RegisterMutatorsContext) {
		ctx.TopDown("apex_deps", apexDepsMutator)
		ctx.BottomUp("apex", apexMutator)
	})
}

// Mark the direct and transitive dependencies of apex bundles so that they
// can be built for the apex bundles.
func apexDepsMutator(mctx android.TopDownMutatorContext) {
	if a, ok := mctx.Module().(*apexBundle); ok {
		apexBundleName := mctx.ModuleName()
		mctx.WalkDeps(func(child, parent android.Module) bool {
			depName := mctx.OtherModuleName(child)
			// If the parent is apexBundle, this child is directly depended.
			_, directDep := parent.(*apexBundle)
			if a.installable() && !a.testApex {
				// TODO(b/123892969): Workaround for not having any way to annotate test-apexs
				// non-installable apex's cannot be installed and so should not prevent libraries from being
				// installed to the system.
				android.UpdateApexDependency(apexBundleName, depName, directDep)
			}

			if am, ok := child.(android.ApexModule); ok && am.CanHaveApexVariants() {
				am.BuildForApex(apexBundleName)
				return true
			} else {
				return false
			}
		})
	}
}

// Create apex variations if a module is included in APEX(s).
func apexMutator(mctx android.BottomUpMutatorContext) {
	if am, ok := mctx.Module().(android.ApexModule); ok && am.CanHaveApexVariants() {
		am.CreateApexVariations(mctx)
	} else if _, ok := mctx.Module().(*apexBundle); ok {
		// apex bundle itself is mutated so that it and its modules have same
		// apex variant.
		apexBundleName := mctx.ModuleName()
		mctx.CreateVariations(apexBundleName)
	}
}

type apexNativeDependencies struct {
	// List of native libraries
	Native_shared_libs []string
	// List of native executables
	Binaries []string
}
type apexMultilibProperties struct {
	// Native dependencies whose compile_multilib is "first"
	First apexNativeDependencies

	// Native dependencies whose compile_multilib is "both"
	Both apexNativeDependencies

	// Native dependencies whose compile_multilib is "prefer32"
	Prefer32 apexNativeDependencies

	// Native dependencies whose compile_multilib is "32"
	Lib32 apexNativeDependencies

	// Native dependencies whose compile_multilib is "64"
	Lib64 apexNativeDependencies
}

type apexBundleProperties struct {
	// Json manifest file describing meta info of this APEX bundle. Default:
	// "apex_manifest.json"
	Manifest *string `android:"path"`

	// AndroidManifest.xml file used for the zip container of this APEX bundle.
	// If unspecified, a default one is automatically generated.
	AndroidManifest *string `android:"path"`

	// Canonical name of the APEX bundle in the manifest file.
	// If unspecified, defaults to the value of name
	Apex_name *string

	// Determines the file contexts file for setting security context to each file in this APEX bundle.
	// Specifically, when this is set to <value>, /system/sepolicy/apex/<value>_file_contexts file is
	// used.
	// Default: <name_of_this_module>
	File_contexts *string

	// List of native shared libs that are embedded inside this APEX bundle
	Native_shared_libs []string

	// List of native executables that are embedded inside this APEX bundle
	Binaries []string

	// List of java libraries that are embedded inside this APEX bundle
	Java_libs []string

	// List of prebuilt files that are embedded inside this APEX bundle
	Prebuilts []string

	// Name of the apex_key module that provides the private key to sign APEX
	Key *string

	// The type of APEX to build. Controls what the APEX payload is. Either
	// 'image', 'zip' or 'both'. Default: 'image'.
	Payload_type *string

	// The name of a certificate in the default certificate directory, blank to use the default product certificate,
	// or an android_app_certificate module name in the form ":module".
	Certificate *string

	// Whether this APEX is installable to one of the partitions. Default: true.
	Installable *bool

	// For native libraries and binaries, use the vendor variant instead of the core (platform) variant.
	// Default is false.
	Use_vendor *bool

	// For telling the apex to ignore special handling for system libraries such as bionic. Default is false.
	Ignore_system_library_special_case *bool

	Multilib apexMultilibProperties

	// List of sanitizer names that this APEX is enabled for
	SanitizerNames []string `blueprint:"mutated"`
}

type apexTargetBundleProperties struct {
	Target struct {
		// Multilib properties only for android.
		Android struct {
			Multilib apexMultilibProperties
		}
		// Multilib properties only for host.
		Host struct {
			Multilib apexMultilibProperties
		}
		// Multilib properties only for host linux_bionic.
		Linux_bionic struct {
			Multilib apexMultilibProperties
		}
		// Multilib properties only for host linux_glibc.
		Linux_glibc struct {
			Multilib apexMultilibProperties
		}
	}
}

type apexFileClass int

const (
	etc apexFileClass = iota
	nativeSharedLib
	nativeExecutable
	shBinary
	pyBinary
	goBinary
	javaSharedLib
)

type apexPackaging int

const (
	imageApex apexPackaging = iota
	zipApex
	both
)

func (a apexPackaging) image() bool {
	switch a {
	case imageApex, both:
		return true
	}
	return false
}

func (a apexPackaging) zip() bool {
	switch a {
	case zipApex, both:
		return true
	}
	return false
}

func (a apexPackaging) suffix() string {
	switch a {
	case imageApex:
		return imageApexSuffix
	case zipApex:
		return zipApexSuffix
	case both:
		panic(fmt.Errorf("must be either zip or image"))
	default:
		panic(fmt.Errorf("unkonwn APEX type %d", a))
	}
}

func (a apexPackaging) name() string {
	switch a {
	case imageApex:
		return imageApexType
	case zipApex:
		return zipApexType
	case both:
		panic(fmt.Errorf("must be either zip or image"))
	default:
		panic(fmt.Errorf("unkonwn APEX type %d", a))
	}
}

func (class apexFileClass) NameInMake() string {
	switch class {
	case etc:
		return "ETC"
	case nativeSharedLib:
		return "SHARED_LIBRARIES"
	case nativeExecutable, shBinary, pyBinary, goBinary:
		return "EXECUTABLES"
	case javaSharedLib:
		return "JAVA_LIBRARIES"
	default:
		panic(fmt.Errorf("unkonwn class %d", class))
	}
}

type apexFile struct {
	builtFile  android.Path
	moduleName string
	installDir string
	class      apexFileClass
	module     android.Module
	symlinks   []string
}

type apexBundle struct {
	android.ModuleBase
	android.DefaultableModuleBase

	properties       apexBundleProperties
	targetProperties apexTargetBundleProperties

	apexTypes apexPackaging

	bundleModuleFile android.WritablePath
	outputFiles      map[apexPackaging]android.WritablePath
	installDir       android.OutputPath

	public_key_file  android.Path
	private_key_file android.Path

	container_certificate_file android.Path
	container_private_key_file android.Path

	mergedNoticeFile android.WritablePath

	// list of files to be included in this apex
	filesInfo []apexFile

	// list of module names that this APEX is depending on
	externalDeps []string

	flattened bool

	testApex bool
}

func addDependenciesForNativeModules(ctx android.BottomUpMutatorContext,
	native_shared_libs []string, binaries []string, arch string, imageVariation string) {
	// Use *FarVariation* to be able to depend on modules having
	// conflicting variations with this module. This is required since
	// arch variant of an APEX bundle is 'common' but it is 'arm' or 'arm64'
	// for native shared libs.
	ctx.AddFarVariationDependencies([]blueprint.Variation{
		{Mutator: "arch", Variation: arch},
		{Mutator: "image", Variation: imageVariation},
		{Mutator: "link", Variation: "shared"},
		{Mutator: "version", Variation: ""}, // "" is the non-stub variant
	}, sharedLibTag, native_shared_libs...)

	ctx.AddFarVariationDependencies([]blueprint.Variation{
		{Mutator: "arch", Variation: arch},
		{Mutator: "image", Variation: imageVariation},
	}, executableTag, binaries...)
}

func (a *apexBundle) combineProperties(ctx android.BottomUpMutatorContext) {
	if ctx.Os().Class == android.Device {
		proptools.AppendProperties(&a.properties.Multilib, &a.targetProperties.Target.Android.Multilib, nil)
	} else {
		proptools.AppendProperties(&a.properties.Multilib, &a.targetProperties.Target.Host.Multilib, nil)
		if ctx.Os().Bionic() {
			proptools.AppendProperties(&a.properties.Multilib, &a.targetProperties.Target.Linux_bionic.Multilib, nil)
		} else {
			proptools.AppendProperties(&a.properties.Multilib, &a.targetProperties.Target.Linux_glibc.Multilib, nil)
		}
	}
}

func (a *apexBundle) DepsMutator(ctx android.BottomUpMutatorContext) {

	targets := ctx.MultiTargets()
	config := ctx.DeviceConfig()

	a.combineProperties(ctx)

	has32BitTarget := false
	for _, target := range targets {
		if target.Arch.ArchType.Multilib == "lib32" {
			has32BitTarget = true
		}
	}
	for i, target := range targets {
		// When multilib.* is omitted for native_shared_libs, it implies
		// multilib.both.
		ctx.AddFarVariationDependencies([]blueprint.Variation{
			{Mutator: "arch", Variation: target.String()},
			{Mutator: "image", Variation: a.getImageVariation(config)},
			{Mutator: "link", Variation: "shared"},
		}, sharedLibTag, a.properties.Native_shared_libs...)

		// Add native modules targetting both ABIs
		addDependenciesForNativeModules(ctx,
			a.properties.Multilib.Both.Native_shared_libs,
			a.properties.Multilib.Both.Binaries, target.String(),
			a.getImageVariation(config))

		isPrimaryAbi := i == 0
		if isPrimaryAbi {
			// When multilib.* is omitted for binaries, it implies
			// multilib.first.
			ctx.AddFarVariationDependencies([]blueprint.Variation{
				{Mutator: "arch", Variation: target.String()},
				{Mutator: "image", Variation: a.getImageVariation(config)},
			}, executableTag, a.properties.Binaries...)

			// Add native modules targetting the first ABI
			addDependenciesForNativeModules(ctx,
				a.properties.Multilib.First.Native_shared_libs,
				a.properties.Multilib.First.Binaries, target.String(),
				a.getImageVariation(config))

			// When multilib.* is omitted for prebuilts, it implies multilib.first.
			ctx.AddFarVariationDependencies([]blueprint.Variation{
				{Mutator: "arch", Variation: target.String()},
			}, prebuiltTag, a.properties.Prebuilts...)
		}

		switch target.Arch.ArchType.Multilib {
		case "lib32":
			// Add native modules targetting 32-bit ABI
			addDependenciesForNativeModules(ctx,
				a.properties.Multilib.Lib32.Native_shared_libs,
				a.properties.Multilib.Lib32.Binaries, target.String(),
				a.getImageVariation(config))

			addDependenciesForNativeModules(ctx,
				a.properties.Multilib.Prefer32.Native_shared_libs,
				a.properties.Multilib.Prefer32.Binaries, target.String(),
				a.getImageVariation(config))
		case "lib64":
			// Add native modules targetting 64-bit ABI
			addDependenciesForNativeModules(ctx,
				a.properties.Multilib.Lib64.Native_shared_libs,
				a.properties.Multilib.Lib64.Binaries, target.String(),
				a.getImageVariation(config))

			if !has32BitTarget {
				addDependenciesForNativeModules(ctx,
					a.properties.Multilib.Prefer32.Native_shared_libs,
					a.properties.Multilib.Prefer32.Binaries, target.String(),
					a.getImageVariation(config))
			}

			if strings.HasPrefix(ctx.ModuleName(), "com.android.runtime") && target.Os.Class == android.Device {
				for _, sanitizer := range ctx.Config().SanitizeDevice() {
					if sanitizer == "hwaddress" {
						addDependenciesForNativeModules(ctx,
							[]string{"libclang_rt.hwasan-aarch64-android"},
							nil, target.String(), a.getImageVariation(config))
						break
					}
				}
			}
		}

	}

	ctx.AddFarVariationDependencies([]blueprint.Variation{
		{Mutator: "arch", Variation: "android_common"},
	}, javaLibTag, a.properties.Java_libs...)

	if String(a.properties.Key) == "" {
		ctx.ModuleErrorf("key is missing")
		return
	}
	ctx.AddDependency(ctx.Module(), keyTag, String(a.properties.Key))

	cert := android.SrcIsModule(a.getCertString(ctx))
	if cert != "" {
		ctx.AddDependency(ctx.Module(), certificateTag, cert)
	}
}

func (a *apexBundle) getCertString(ctx android.BaseModuleContext) string {
	certificate, overridden := ctx.DeviceConfig().OverrideCertificateFor(ctx.ModuleName())
	if overridden {
		return ":" + certificate
	}
	return String(a.properties.Certificate)
}

func (a *apexBundle) OutputFiles(tag string) (android.Paths, error) {
	switch tag {
	case "":
		if file, ok := a.outputFiles[imageApex]; ok {
			return android.Paths{file}, nil
		} else {
			return nil, nil
		}
	default:
		return nil, fmt.Errorf("unsupported module reference tag %q", tag)
	}
}

func (a *apexBundle) installable() bool {
	return a.properties.Installable == nil || proptools.Bool(a.properties.Installable)
}

func (a *apexBundle) getImageVariation(config android.DeviceConfig) string {
	if config.VndkVersion() != "" && proptools.Bool(a.properties.Use_vendor) {
		return "vendor"
	} else {
		return "core"
	}
}

func (a *apexBundle) EnableSanitizer(sanitizerName string) {
	if !android.InList(sanitizerName, a.properties.SanitizerNames) {
		a.properties.SanitizerNames = append(a.properties.SanitizerNames, sanitizerName)
	}
}

func (a *apexBundle) IsSanitizerEnabled(ctx android.BaseModuleContext, sanitizerName string) bool {
	if android.InList(sanitizerName, a.properties.SanitizerNames) {
		return true
	}

	// Then follow the global setting
	globalSanitizerNames := []string{}
	if a.Host() {
		globalSanitizerNames = ctx.Config().SanitizeHost()
	} else {
		arches := ctx.Config().SanitizeDeviceArch()
		if len(arches) == 0 || android.InList(a.Arch().ArchType.Name, arches) {
			globalSanitizerNames = ctx.Config().SanitizeDevice()
		}
	}
	return android.InList(sanitizerName, globalSanitizerNames)
}

func getCopyManifestForNativeLibrary(cc *cc.Module, handleSpecialLibs bool) (fileToCopy android.Path, dirInApex string) {
	// Decide the APEX-local directory by the multilib of the library
	// In the future, we may query this to the module.
	switch cc.Arch().ArchType.Multilib {
	case "lib32":
		dirInApex = "lib"
	case "lib64":
		dirInApex = "lib64"
	}
	dirInApex = filepath.Join(dirInApex, cc.RelativeInstallPath())
	if !cc.Arch().Native {
		dirInApex = filepath.Join(dirInApex, cc.Arch().ArchType.String())
	}
	if handleSpecialLibs {
		switch cc.Name() {
		case "libc", "libm", "libdl":
			// Special case for bionic libs. This is to prevent the bionic libs
			// from being included in the search path /apex/com.android.apex/lib.
			// This exclusion is required because bionic libs in the runtime APEX
			// are available via the legacy paths /system/lib/libc.so, etc. By the
			// init process, the bionic libs in the APEX are bind-mounted to the
			// legacy paths and thus will be loaded into the default linker namespace.
			// If the bionic libs are directly in /apex/com.android.apex/lib then
			// the same libs will be again loaded to the runtime linker namespace,
			// which will result double loading of bionic libs that isn't supported.
			dirInApex = filepath.Join(dirInApex, "bionic")
		}
	}

	fileToCopy = cc.OutputFile().Path()
	return
}

func getCopyManifestForExecutable(cc *cc.Module) (fileToCopy android.Path, dirInApex string) {
	dirInApex = filepath.Join("bin", cc.RelativeInstallPath())
	fileToCopy = cc.OutputFile().Path()
	return
}

func getCopyManifestForPyBinary(py *python.Module) (fileToCopy android.Path, dirInApex string) {
	dirInApex = "bin"
	fileToCopy = py.HostToolPath().Path()
	return
}
func getCopyManifestForGoBinary(ctx android.ModuleContext, gb bootstrap.GoBinaryTool) (fileToCopy android.Path, dirInApex string) {
	dirInApex = "bin"
	s, err := filepath.Rel(android.PathForOutput(ctx).String(), gb.InstallPath())
	if err != nil {
		ctx.ModuleErrorf("Unable to use compiled binary at %s", gb.InstallPath())
		return
	}
	fileToCopy = android.PathForOutput(ctx, s)
	return
}

func getCopyManifestForShBinary(sh *android.ShBinary) (fileToCopy android.Path, dirInApex string) {
	dirInApex = filepath.Join("bin", sh.SubDir())
	fileToCopy = sh.OutputFile()
	return
}

func getCopyManifestForJavaLibrary(java *java.Library) (fileToCopy android.Path, dirInApex string) {
	dirInApex = "javalib"
	fileToCopy = java.DexJarFile()
	return
}

func getCopyManifestForPrebuiltEtc(prebuilt *android.PrebuiltEtc) (fileToCopy android.Path, dirInApex string) {
	dirInApex = filepath.Join("etc", prebuilt.SubDir())
	fileToCopy = prebuilt.OutputFile()
	return
}

func (a *apexBundle) GenerateAndroidBuildActions(ctx android.ModuleContext) {
	filesInfo := []apexFile{}

	if a.properties.Payload_type == nil || *a.properties.Payload_type == "image" {
		a.apexTypes = imageApex
	} else if *a.properties.Payload_type == "zip" {
		a.apexTypes = zipApex
	} else if *a.properties.Payload_type == "both" {
		a.apexTypes = both
	} else {
		ctx.PropertyErrorf("type", "%q is not one of \"image\", \"zip\", or \"both\".", *a.properties.Payload_type)
		return
	}

	handleSpecialLibs := !android.Bool(a.properties.Ignore_system_library_special_case)

	ctx.WalkDepsBlueprint(func(child, parent blueprint.Module) bool {
		if _, ok := parent.(*apexBundle); ok {
			// direct dependencies
			depTag := ctx.OtherModuleDependencyTag(child)
			depName := ctx.OtherModuleName(child)
			switch depTag {
			case sharedLibTag:
				if cc, ok := child.(*cc.Module); ok {
					fileToCopy, dirInApex := getCopyManifestForNativeLibrary(cc, handleSpecialLibs)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, nativeSharedLib, cc, nil})
					return true
				} else {
					ctx.PropertyErrorf("native_shared_libs", "%q is not a cc_library or cc_library_shared module", depName)
				}
			case executableTag:
				if cc, ok := child.(*cc.Module); ok {
					if !cc.Arch().Native {
						// There is only one 'bin' directory so we shouldn't bother copying in
						// native-bridge'd binaries and only use main ones.
						return true
					}
					fileToCopy, dirInApex := getCopyManifestForExecutable(cc)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, nativeExecutable, cc, cc.Symlinks()})
					return true
				} else if sh, ok := child.(*android.ShBinary); ok {
					fileToCopy, dirInApex := getCopyManifestForShBinary(sh)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, shBinary, sh, nil})
				} else if py, ok := child.(*python.Module); ok && py.HostToolPath().Valid() {
					fileToCopy, dirInApex := getCopyManifestForPyBinary(py)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, pyBinary, py, nil})
				} else if gb, ok := child.(bootstrap.GoBinaryTool); ok && a.Host() {
					fileToCopy, dirInApex := getCopyManifestForGoBinary(ctx, gb)
					// NB: Since go binaries are static we don't need the module for anything here, which is
					// good since the go tool is a blueprint.Module not an android.Module like we would
					// normally use.
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, goBinary, nil, nil})
				} else {
					ctx.PropertyErrorf("binaries", "%q is neither cc_binary, (embedded) py_binary, (host) blueprint_go_binary, (host) bootstrap_go_binary, nor sh_binary", depName)
				}
			case javaLibTag:
				if java, ok := child.(*java.Library); ok {
					fileToCopy, dirInApex := getCopyManifestForJavaLibrary(java)
					if fileToCopy == nil {
						ctx.PropertyErrorf("java_libs", "%q is not configured to be compiled into dex", depName)
					} else {
						filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, javaSharedLib, java, nil})
					}
					return true
				} else {
					ctx.PropertyErrorf("java_libs", "%q is not a java_library module", depName)
				}
			case prebuiltTag:
				if prebuilt, ok := child.(*android.PrebuiltEtc); ok {
					fileToCopy, dirInApex := getCopyManifestForPrebuiltEtc(prebuilt)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, etc, prebuilt, nil})
					return true
				} else {
					ctx.PropertyErrorf("prebuilts", "%q is not a prebuilt_etc module", depName)
				}
			case keyTag:
				if key, ok := child.(*apexKey); ok {
					a.private_key_file = key.private_key_file
					a.public_key_file = key.public_key_file
					return false
				} else {
					ctx.PropertyErrorf("key", "%q is not an apex_key module", depName)
				}
			case certificateTag:
				if dep, ok := child.(*java.AndroidAppCertificate); ok {
					a.container_certificate_file = dep.Certificate.Pem
					a.container_private_key_file = dep.Certificate.Key
					return false
				} else {
					ctx.ModuleErrorf("certificate dependency %q must be an android_app_certificate module", depName)
				}
			}
		} else {
			// indirect dependencies
			if am, ok := child.(android.ApexModule); ok && am.CanHaveApexVariants() && am.IsInstallableToApex() {
				if cc, ok := child.(*cc.Module); ok {
					if !a.Host() && (cc.IsStubs() || cc.HasStubsVariants()) {
						// If the dependency is a stubs lib, don't include it in this APEX,
						// but make sure that the lib is installed on the device.
						// In case no APEX is having the lib, the lib is installed to the system
						// partition.
						//
						// Always include if we are a host-apex however since those won't have any
						// system libraries.
						if !android.DirectlyInAnyApex(ctx, cc.Name()) && !android.InList(cc.Name(), a.externalDeps) {
							a.externalDeps = append(a.externalDeps, cc.Name())
						}
						// Don't track further
						return false
					}
					depName := ctx.OtherModuleName(child)
					fileToCopy, dirInApex := getCopyManifestForNativeLibrary(cc, handleSpecialLibs)
					filesInfo = append(filesInfo, apexFile{fileToCopy, depName, dirInApex, nativeSharedLib, cc, nil})
					return true
				}
			}
		}
		return false
	})

	a.flattened = ctx.Config().FlattenApex() && !ctx.Config().UnbundledBuild()
	if a.private_key_file == nil {
		ctx.PropertyErrorf("key", "private_key for %q could not be found", String(a.properties.Key))
		return
	}

	// remove duplicates in filesInfo
	removeDup := func(filesInfo []apexFile) []apexFile {
		encountered := make(map[android.Path]bool)
		result := []apexFile{}
		for _, f := range filesInfo {
			if !encountered[f.builtFile] {
				encountered[f.builtFile] = true
				result = append(result, f)
			}
		}
		return result
	}
	filesInfo = removeDup(filesInfo)

	// to have consistent build rules
	sort.Slice(filesInfo, func(i, j int) bool {
		return filesInfo[i].builtFile.String() < filesInfo[j].builtFile.String()
	})

	// prepend the name of this APEX to the module names. These names will be the names of
	// modules that will be defined if the APEX is flattened.
	for i := range filesInfo {
		filesInfo[i].moduleName = ctx.ModuleName() + "." + filesInfo[i].moduleName
	}

	a.installDir = android.PathForModuleInstall(ctx, "apex")
	a.filesInfo = filesInfo

	a.buildNoticeFile(ctx)

	if a.apexTypes.zip() {
		a.buildUnflattenedApex(ctx, zipApex)
	}
	if a.apexTypes.image() {
		// Build rule for unflattened APEX is created even when ctx.Config().FlattenApex()
		// is true. This is to support referencing APEX via ":<module_name" syntax
		// in other modules. It is in AndroidMk where the selection of flattened
		// or unflattened APEX is made.
		a.buildUnflattenedApex(ctx, imageApex)
		a.buildFlattenedApex(ctx)
	}
}

func (a *apexBundle) buildNoticeFile(ctx android.ModuleContext) {
	noticeFiles := []android.Path{}
	for _, f := range a.filesInfo {
		if f.module != nil {
			notice := f.module.NoticeFile()
			if notice.Valid() {
				noticeFiles = append(noticeFiles, notice.Path())
			}
		}
	}
	// append the notice file specified in the apex module itself
	if a.NoticeFile().Valid() {
		noticeFiles = append(noticeFiles, a.NoticeFile().Path())
	}

	if len(noticeFiles) > 0 {
		a.mergedNoticeFile = android.PathForModuleOut(ctx, "NOTICE")
		android.MergeNotices(ctx, a.mergedNoticeFile, noticeFiles)
	}
}

func (a *apexBundle) buildUnflattenedApex(ctx android.ModuleContext, apexType apexPackaging) {
	cert := String(a.properties.Certificate)
	if cert != "" && android.SrcIsModule(cert) == "" {
		defaultDir := ctx.Config().DefaultAppCertificateDir(ctx)
		a.container_certificate_file = defaultDir.Join(ctx, cert+".x509.pem")
		a.container_private_key_file = defaultDir.Join(ctx, cert+".pk8")
	} else if cert == "" {
		pem, key := ctx.Config().DefaultAppCertificate(ctx)
		a.container_certificate_file = pem
		a.container_private_key_file = key
	}

	manifest := android.PathForModuleSrc(ctx, proptools.StringDefault(a.properties.Manifest, "apex_manifest.json"))

	var abis []string
	for _, target := range ctx.MultiTargets() {
		if len(target.Arch.Abi) > 0 {
			abis = append(abis, target.Arch.Abi[0])
		}
	}

	abis = android.FirstUniqueStrings(abis)

	suffix := apexType.suffix()
	unsignedOutputFile := android.PathForModuleOut(ctx, ctx.ModuleName()+suffix+".unsigned")

	filesToCopy := []android.Path{}
	for _, f := range a.filesInfo {
		filesToCopy = append(filesToCopy, f.builtFile)
	}

	copyCommands := []string{}
	for i, src := range filesToCopy {
		dest := filepath.Join(a.filesInfo[i].installDir, src.Base())
		dest_path := filepath.Join(android.PathForModuleOut(ctx, "image"+suffix).String(), dest)
		copyCommands = append(copyCommands, "mkdir -p "+filepath.Dir(dest_path))
		copyCommands = append(copyCommands, "cp "+src.String()+" "+dest_path)
		for _, sym := range a.filesInfo[i].symlinks {
			symlinkDest := filepath.Join(filepath.Dir(dest_path), sym)
			copyCommands = append(copyCommands, "ln -s "+filepath.Base(dest)+" "+symlinkDest)
		}
	}
	implicitInputs := append(android.Paths(nil), filesToCopy...)
	implicitInputs = append(implicitInputs, manifest)

	outHostBinDir := android.PathForOutput(ctx, "host", ctx.Config().PrebuiltOS(), "bin").String()
	prebuiltSdkToolsBinDir := filepath.Join("prebuilts", "sdk", "tools", runtime.GOOS, "bin")

	if apexType.image() {
		// files and dirs that will be created in APEX
		var readOnlyPaths []string
		var executablePaths []string // this also includes dirs
		for _, f := range a.filesInfo {
			pathInApex := filepath.Join(f.installDir, f.builtFile.Base())
			if f.installDir == "bin" {
				executablePaths = append(executablePaths, pathInApex)
				for _, s := range f.symlinks {
					executablePaths = append(executablePaths, filepath.Join("bin", s))
				}
			} else {
				readOnlyPaths = append(readOnlyPaths, pathInApex)
			}
			dir := f.installDir
			for !android.InList(dir, executablePaths) && dir != "" {
				executablePaths = append(executablePaths, dir)
				dir, _ = filepath.Split(dir) // move up to the parent
				if len(dir) > 0 {
					// remove trailing slash
					dir = dir[:len(dir)-1]
				}
			}
		}
		sort.Strings(readOnlyPaths)
		sort.Strings(executablePaths)
		cannedFsConfig := android.PathForModuleOut(ctx, "canned_fs_config")
		ctx.Build(pctx, android.BuildParams{
			Rule:        generateFsConfig,
			Output:      cannedFsConfig,
			Description: "generate fs config",
			Args: map[string]string{
				"ro_paths":   strings.Join(readOnlyPaths, " "),
				"exec_paths": strings.Join(executablePaths, " "),
			},
		})

		fcName := proptools.StringDefault(a.properties.File_contexts, ctx.ModuleName())
		fileContextsPath := "system/sepolicy/apex/" + fcName + "-file_contexts"
		fileContextsOptionalPath := android.ExistentPathForSource(ctx, fileContextsPath)
		if !fileContextsOptionalPath.Valid() {
			ctx.ModuleErrorf("Cannot find file_contexts file: %q", fileContextsPath)
			return
		}
		fileContexts := fileContextsOptionalPath.Path()

		optFlags := []string{}

		// Additional implicit inputs.
		implicitInputs = append(implicitInputs, cannedFsConfig, fileContexts, a.private_key_file, a.public_key_file)
		optFlags = append(optFlags, "--pubkey "+a.public_key_file.String())

		manifestPackageName, overridden := ctx.DeviceConfig().OverrideManifestPackageNameFor(ctx.ModuleName())
		if overridden {
			optFlags = append(optFlags, "--override_apk_package_name "+manifestPackageName)
		}

		if a.properties.AndroidManifest != nil {
			androidManifestFile := android.PathForModuleSrc(ctx, proptools.String(a.properties.AndroidManifest))
			implicitInputs = append(implicitInputs, androidManifestFile)
			optFlags = append(optFlags, "--android_manifest "+androidManifestFile.String())
		}

		targetSdkVersion := ctx.Config().DefaultAppTargetSdk()
		if targetSdkVersion == ctx.Config().PlatformSdkCodename() &&
			ctx.Config().UnbundledBuild() &&
			!ctx.Config().UnbundledBuildUsePrebuiltSdks() &&
			ctx.Config().IsEnvTrue("UNBUNDLED_BUILD_TARGET_SDK_WITH_API_FINGERPRINT") {
			apiFingerprint := java.ApiFingerprintPath(ctx)
			targetSdkVersion += fmt.Sprintf(".$$(cat %s)", apiFingerprint.String())
			implicitInputs = append(implicitInputs, apiFingerprint)
		}
		optFlags = append(optFlags, "--target_sdk_version "+targetSdkVersion)

		ctx.Build(pctx, android.BuildParams{
			Rule:        apexRule,
			Implicits:   implicitInputs,
			Output:      unsignedOutputFile,
			Description: "apex (" + apexType.name() + ")",
			Args: map[string]string{
				"tool_path":        outHostBinDir + ":" + prebuiltSdkToolsBinDir,
				"image_dir":        android.PathForModuleOut(ctx, "image"+suffix).String(),
				"copy_commands":    strings.Join(copyCommands, " && "),
				"manifest":         manifest.String(),
				"file_contexts":    fileContexts.String(),
				"canned_fs_config": cannedFsConfig.String(),
				"key":              a.private_key_file.String(),
				"opt_flags":        strings.Join(optFlags, " "),
			},
		})

		apexProtoFile := android.PathForModuleOut(ctx, ctx.ModuleName()+".pb"+suffix)
		bundleModuleFile := android.PathForModuleOut(ctx, ctx.ModuleName()+suffix+"-base.zip")
		a.bundleModuleFile = bundleModuleFile

		ctx.Build(pctx, android.BuildParams{
			Rule:        apexProtoConvertRule,
			Input:       unsignedOutputFile,
			Output:      apexProtoFile,
			Description: "apex proto convert",
		})

		ctx.Build(pctx, android.BuildParams{
			Rule:        apexBundleRule,
			Input:       apexProtoFile,
			Output:      a.bundleModuleFile,
			Description: "apex bundle module",
			Args: map[string]string{
				"abi": strings.Join(abis, "."),
			},
		})
	} else {
		ctx.Build(pctx, android.BuildParams{
			Rule:        zipApexRule,
			Implicits:   implicitInputs,
			Output:      unsignedOutputFile,
			Description: "apex (" + apexType.name() + ")",
			Args: map[string]string{
				"tool_path":     outHostBinDir + ":" + prebuiltSdkToolsBinDir,
				"image_dir":     android.PathForModuleOut(ctx, "image"+suffix).String(),
				"copy_commands": strings.Join(copyCommands, " && "),
				"manifest":      manifest.String(),
			},
		})
	}

	a.outputFiles[apexType] = android.PathForModuleOut(ctx, ctx.ModuleName()+suffix)
	ctx.Build(pctx, android.BuildParams{
		Rule:        java.Signapk,
		Description: "signapk",
		Output:      a.outputFiles[apexType],
		Input:       unsignedOutputFile,
		Implicits: []android.Path{
			a.container_certificate_file,
			a.container_private_key_file,
		},
		Args: map[string]string{
			"certificates": a.container_certificate_file.String() + " " + a.container_private_key_file.String(),
			"flags":        "-a 4096", //alignment
		},
	})

	// Install to $OUT/soong/{target,host}/.../apex
	if a.installable() && (!ctx.Config().FlattenApex() || apexType.zip()) {
		ctx.InstallFile(a.installDir, ctx.ModuleName()+suffix, a.outputFiles[apexType])
	}
}

func (a *apexBundle) buildFlattenedApex(ctx android.ModuleContext) {
	if a.installable() {
		// For flattened APEX, do nothing but make sure that apex_manifest.json and apex_pubkey are also copied along
		// with other ordinary files.
		manifest := android.PathForModuleSrc(ctx, proptools.StringDefault(a.properties.Manifest, "apex_manifest.json"))

		// rename to apex_manifest.json
		copiedManifest := android.PathForModuleOut(ctx, "apex_manifest.json")
		ctx.Build(pctx, android.BuildParams{
			Rule:   android.Cp,
			Input:  manifest,
			Output: copiedManifest,
		})
		a.filesInfo = append(a.filesInfo, apexFile{copiedManifest, ctx.ModuleName() + ".apex_manifest.json", ".", etc, nil, nil})

		// rename to apex_pubkey
		copiedPubkey := android.PathForModuleOut(ctx, "apex_pubkey")
		ctx.Build(pctx, android.BuildParams{
			Rule:   android.Cp,
			Input:  a.public_key_file,
			Output: copiedPubkey,
		})
		a.filesInfo = append(a.filesInfo, apexFile{copiedPubkey, ctx.ModuleName() + ".apex_pubkey", ".", etc, nil, nil})

		if ctx.Config().FlattenApex() {
			for _, fi := range a.filesInfo {
				dir := filepath.Join("apex", ctx.ModuleName(), fi.installDir)
				target := ctx.InstallFile(android.PathForModuleInstall(ctx, dir), fi.builtFile.Base(), fi.builtFile)
				for _, sym := range fi.symlinks {
					ctx.InstallSymlink(android.PathForModuleInstall(ctx, dir), sym, target)
				}
			}
		}
	}
}

func (a *apexBundle) AndroidMk() android.AndroidMkData {
	writers := []android.AndroidMkData{}
	if a.apexTypes.image() {
		writers = append(writers, a.androidMkForType(imageApex))
	}
	if a.apexTypes.zip() {
		writers = append(writers, a.androidMkForType(zipApex))
	}
	return android.AndroidMkData{
		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
			for _, data := range writers {
				data.Custom(w, name, prefix, moduleDir, data)
			}
		}}
}

func (a *apexBundle) androidMkForFiles(w io.Writer, name, moduleDir string, apexType apexPackaging) []string {
	moduleNames := []string{}

	for _, fi := range a.filesInfo {
		if cc, ok := fi.module.(*cc.Module); ok && cc.Properties.HideFromMake {
			continue
		}
		if !android.InList(fi.moduleName, moduleNames) {
			moduleNames = append(moduleNames, fi.moduleName)
		}
		fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
		fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
		fmt.Fprintln(w, "LOCAL_MODULE :=", fi.moduleName)
		// /apex/<name>/{lib|framework|...}
		pathWhenActivated := filepath.Join("$(PRODUCT_OUT)", "apex",
			proptools.StringDefault(a.properties.Apex_name, name), fi.installDir)
		if a.flattened && apexType.image() {
			// /system/apex/<name>/{lib|framework|...}
			fmt.Fprintln(w, "LOCAL_MODULE_PATH :=", filepath.Join("$(OUT_DIR)",
				a.installDir.RelPathString(), name, fi.installDir))
			fmt.Fprintln(w, "LOCAL_SOONG_SYMBOL_PATH :=", pathWhenActivated)
			if len(fi.symlinks) > 0 {
				fmt.Fprintln(w, "LOCAL_MODULE_SYMLINKS :=", strings.Join(fi.symlinks, " "))
			}

			if fi.module != nil && fi.module.NoticeFile().Valid() {
				fmt.Fprintln(w, "LOCAL_NOTICE_FILE :=", fi.module.NoticeFile().Path().String())
			}
		} else {
			fmt.Fprintln(w, "LOCAL_MODULE_PATH :=", pathWhenActivated)
		}
		fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", fi.builtFile.String())
		fmt.Fprintln(w, "LOCAL_MODULE_CLASS :=", fi.class.NameInMake())
		if fi.module != nil {
			archStr := fi.module.Target().Arch.ArchType.String()
			host := false
			switch fi.module.Target().Os.Class {
			case android.Host:
				if archStr != "common" {
					fmt.Fprintln(w, "LOCAL_MODULE_HOST_ARCH :=", archStr)
				}
				host = true
			case android.HostCross:
				if archStr != "common" {
					fmt.Fprintln(w, "LOCAL_MODULE_HOST_CROSS_ARCH :=", archStr)
				}
				host = true
			case android.Device:
				if archStr != "common" {
					fmt.Fprintln(w, "LOCAL_MODULE_TARGET_ARCH :=", archStr)
				}
			}
			if host {
				makeOs := fi.module.Target().Os.String()
				if fi.module.Target().Os == android.Linux || fi.module.Target().Os == android.LinuxBionic {
					makeOs = "linux"
				}
				fmt.Fprintln(w, "LOCAL_MODULE_HOST_OS :=", makeOs)
				fmt.Fprintln(w, "LOCAL_IS_HOST_MODULE := true")
			}
		}
		if fi.class == javaSharedLib {
			javaModule := fi.module.(*java.Library)
			// soong_java_prebuilt.mk sets LOCAL_MODULE_SUFFIX := .jar  Therefore
			// we need to remove the suffix from LOCAL_MODULE_STEM, otherwise
			// we will have foo.jar.jar
			fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", strings.TrimSuffix(fi.builtFile.Base(), ".jar"))
			fmt.Fprintln(w, "LOCAL_SOONG_CLASSES_JAR :=", javaModule.ImplementationAndResourcesJars()[0].String())
			fmt.Fprintln(w, "LOCAL_SOONG_HEADER_JAR :=", javaModule.HeaderJars()[0].String())
			fmt.Fprintln(w, "LOCAL_SOONG_DEX_JAR :=", fi.builtFile.String())
			fmt.Fprintln(w, "LOCAL_DEX_PREOPT := false")
			fmt.Fprintln(w, "include $(BUILD_SYSTEM)/soong_java_prebuilt.mk")
		} else if fi.class == nativeSharedLib || fi.class == nativeExecutable {
			fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", fi.builtFile.Base())
			if cc, ok := fi.module.(*cc.Module); ok {
				if cc.UnstrippedOutputFile() != nil {
					fmt.Fprintln(w, "LOCAL_SOONG_UNSTRIPPED_BINARY :=", cc.UnstrippedOutputFile().String())
				}
				cc.AndroidMkWriteAdditionalDependenciesForSourceAbiDiff(w)
			}
			fmt.Fprintln(w, "include $(BUILD_SYSTEM)/soong_cc_prebuilt.mk")
		} else {
			fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", fi.builtFile.Base())
			fmt.Fprintln(w, "include $(BUILD_PREBUILT)")
		}
	}
	return moduleNames
}

func (a *apexBundle) androidMkForType(apexType apexPackaging) android.AndroidMkData {
	return android.AndroidMkData{
		Custom: func(w io.Writer, name, prefix, moduleDir string, data android.AndroidMkData) {
			moduleNames := []string{}
			if a.installable() {
				moduleNames = a.androidMkForFiles(w, name, moduleDir, apexType)
			}

			if a.flattened && apexType.image() {
				// Only image APEXes can be flattened.
				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
				fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
				fmt.Fprintln(w, "LOCAL_MODULE :=", name)
				if len(moduleNames) > 0 {
					fmt.Fprintln(w, "LOCAL_REQUIRED_MODULES :=", strings.Join(moduleNames, " "))
				}
				fmt.Fprintln(w, "include $(BUILD_PHONY_PACKAGE)")
			} else {
				// zip-apex is the less common type so have the name refer to the image-apex
				// only and use {name}.zip if you want the zip-apex
				if apexType == zipApex && a.apexTypes == both {
					name = name + ".zip"
				}
				fmt.Fprintln(w, "\ninclude $(CLEAR_VARS)")
				fmt.Fprintln(w, "LOCAL_PATH :=", moduleDir)
				fmt.Fprintln(w, "LOCAL_MODULE :=", name)
				fmt.Fprintln(w, "LOCAL_MODULE_CLASS := ETC") // do we need a new class?
				fmt.Fprintln(w, "LOCAL_PREBUILT_MODULE_FILE :=", a.outputFiles[apexType].String())
				fmt.Fprintln(w, "LOCAL_MODULE_PATH :=", filepath.Join("$(OUT_DIR)", a.installDir.RelPathString()))
				fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", name+apexType.suffix())
				fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE :=", !a.installable())
				if a.installable() && a.mergedNoticeFile != nil {
					fmt.Fprintln(w, "LOCAL_NOTICE_FILE :=", a.mergedNoticeFile.String())
				}
				if len(moduleNames) > 0 {
					fmt.Fprintln(w, "LOCAL_REQUIRED_MODULES +=", strings.Join(moduleNames, " "))
				}
				if len(a.externalDeps) > 0 {
					fmt.Fprintln(w, "LOCAL_REQUIRED_MODULES +=", strings.Join(a.externalDeps, " "))
				}
				fmt.Fprintln(w, "include $(BUILD_PREBUILT)")

				if apexType == imageApex {
					fmt.Fprintln(w, "ALL_MODULES.$(LOCAL_MODULE).BUNDLE :=", a.bundleModuleFile.String())
				}
			}
		}}
}

func testApexBundleFactory() android.Module {
	return ApexBundleFactory( /*testApex*/ true)
}

func apexBundleFactory() android.Module {
	return ApexBundleFactory( /*testApex*/ false)
}

func ApexBundleFactory(testApex bool) android.Module {
	module := &apexBundle{
		outputFiles: map[apexPackaging]android.WritablePath{},
		testApex:    testApex,
	}
	module.AddProperties(&module.properties)
	module.AddProperties(&module.targetProperties)
	module.Prefer32(func(ctx android.BaseModuleContext, base *android.ModuleBase, class android.OsClass) bool {
		return class == android.Device && ctx.Config().DevicePrefer32BitExecutables()
	})
	android.InitAndroidMultiTargetsArchModule(module, android.HostAndDeviceSupported, android.MultilibCommon)
	android.InitDefaultableModule(module)
	return module
}

//
// Defaults
//
type Defaults struct {
	android.ModuleBase
	android.DefaultsModuleBase
}

func defaultsFactory() android.Module {
	return DefaultsFactory()
}

func DefaultsFactory(props ...interface{}) android.Module {
	module := &Defaults{}

	module.AddProperties(props...)
	module.AddProperties(
		&apexBundleProperties{},
		&apexTargetBundleProperties{},
	)

	android.InitDefaultsModule(module)
	return module
}

//
// Prebuilt APEX
//
type Prebuilt struct {
	android.ModuleBase
	prebuilt android.Prebuilt

	properties PrebuiltProperties

	inputApex       android.Path
	installDir      android.OutputPath
	installFilename string
	outputApex      android.WritablePath
}

type PrebuiltProperties struct {
	// the path to the prebuilt .apex file to import.
	Source string `blueprint:"mutated"`

	Src  *string
	Arch struct {
		Arm struct {
			Src *string
		}
		Arm64 struct {
			Src *string
		}
		X86 struct {
			Src *string
		}
		X86_64 struct {
			Src *string
		}
	}

	Installable *bool
	// Optional name for the installed apex. If unspecified, name of the
	// module is used as the file name
	Filename *string
}

func (p *Prebuilt) installable() bool {
	return p.properties.Installable == nil || proptools.Bool(p.properties.Installable)
}

func (p *Prebuilt) DepsMutator(ctx android.BottomUpMutatorContext) {
	// This is called before prebuilt_select and prebuilt_postdeps mutators
	// The mutators requires that src to be set correctly for each arch so that
	// arch variants are disabled when src is not provided for the arch.
	if len(ctx.MultiTargets()) != 1 {
		ctx.ModuleErrorf("compile_multilib shouldn't be \"both\" for prebuilt_apex")
		return
	}
	var src string
	switch ctx.MultiTargets()[0].Arch.ArchType {
	case android.Arm:
		src = String(p.properties.Arch.Arm.Src)
	case android.Arm64:
		src = String(p.properties.Arch.Arm64.Src)
	case android.X86:
		src = String(p.properties.Arch.X86.Src)
	case android.X86_64:
		src = String(p.properties.Arch.X86_64.Src)
	default:
		ctx.ModuleErrorf("prebuilt_apex does not support %q", ctx.MultiTargets()[0].Arch.String())
		return
	}
	if src == "" {
		src = String(p.properties.Src)
	}
	p.properties.Source = src
}

func (p *Prebuilt) OutputFiles(tag string) (android.Paths, error) {
	switch tag {
	case "":
		return android.Paths{p.outputApex}, nil
	default:
		return nil, fmt.Errorf("unsupported module reference tag %q", tag)
	}
}

func (p *Prebuilt) InstallFilename() string {
	return proptools.StringDefault(p.properties.Filename, p.BaseModuleName()+imageApexSuffix)
}

func (p *Prebuilt) GenerateAndroidBuildActions(ctx android.ModuleContext) {
	// TODO(jungjw): Check the key validity.
	p.inputApex = p.Prebuilt().SingleSourcePath(ctx)
	p.installDir = android.PathForModuleInstall(ctx, "apex")
	p.installFilename = p.InstallFilename()
	if !strings.HasSuffix(p.installFilename, imageApexSuffix) {
		ctx.ModuleErrorf("filename should end in %s for prebuilt_apex", imageApexSuffix)
	}
	p.outputApex = android.PathForModuleOut(ctx, p.installFilename)
	ctx.Build(pctx, android.BuildParams{
		Rule:   android.Cp,
		Input:  p.inputApex,
		Output: p.outputApex,
	})
	if p.installable() {
		ctx.InstallFile(p.installDir, p.installFilename, p.inputApex)
	}
}

func (p *Prebuilt) Prebuilt() *android.Prebuilt {
	return &p.prebuilt
}

func (p *Prebuilt) Name() string {
	return p.prebuilt.Name(p.ModuleBase.Name())
}

func (p *Prebuilt) AndroidMk() android.AndroidMkData {
	return android.AndroidMkData{
		Class:      "ETC",
		OutputFile: android.OptionalPathForPath(p.inputApex),
		Include:    "$(BUILD_PREBUILT)",
		Extra: []android.AndroidMkExtraFunc{
			func(w io.Writer, outputFile android.Path) {
				fmt.Fprintln(w, "LOCAL_MODULE_PATH :=", filepath.Join("$(OUT_DIR)", p.installDir.RelPathString()))
				fmt.Fprintln(w, "LOCAL_MODULE_STEM :=", p.installFilename)
				fmt.Fprintln(w, "LOCAL_UNINSTALLABLE_MODULE :=", !p.installable())
			},
		},
	}
}

// prebuilt_apex imports an `.apex` file into the build graph as if it was built with apex.
func PrebuiltFactory() android.Module {
	module := &Prebuilt{}
	module.AddProperties(&module.properties)
	android.InitSingleSourcePrebuiltModule(module, &module.properties.Source)
	android.InitAndroidMultiTargetsArchModule(module, android.DeviceSupported, android.MultilibCommon)
	return module
}