android/prebuilt.go - SHIFTPHONES/android_build_soong - Gitiles

 // 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 android

 import (
 	"fmt"
 	"reflect"
 	"strings"

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

 // This file implements common functionality for handling modules that may exist as prebuilts,
 // source, or both.

 func RegisterPrebuiltMutators(ctx RegistrationContext) {
 	ctx.PreArchMutators(RegisterPrebuiltsPreArchMutators)
 	ctx.PostDepsMutators(RegisterPrebuiltsPostDepsMutators)
 }

 // Marks a dependency tag as possibly preventing a reference to a source from being
 // replaced with the prebuilt.
 type ReplaceSourceWithPrebuilt interface {
 	blueprint.DependencyTag

 	// Return true if the dependency defined by this tag should be replaced with the
 	// prebuilt.
 	ReplaceSourceWithPrebuilt() bool
 }

 type prebuiltDependencyTag struct {
 	blueprint.BaseDependencyTag
 }

 var PrebuiltDepTag prebuiltDependencyTag

 // Mark this tag so dependencies that use it are excluded from visibility enforcement.
 func (t prebuiltDependencyTag) ExcludeFromVisibilityEnforcement() {}

 // Mark this tag so dependencies that use it are excluded from APEX contents.
 func (t prebuiltDependencyTag) ExcludeFromApexContents() {}

 var _ ExcludeFromVisibilityEnforcementTag = PrebuiltDepTag
 var _ ExcludeFromApexContentsTag = PrebuiltDepTag

 // UserSuppliedPrebuiltProperties contains the prebuilt properties that can be specified in an
 // Android.bp file.
 type UserSuppliedPrebuiltProperties struct {
 	// When prefer is set to true the prebuilt will be used instead of any source module with
 	// a matching name.
 	Prefer *bool `android:"arch_variant"`

 	// When specified this names a Soong config variable that controls the prefer property.
 	//
 	// If the value of the named Soong config variable is true then prefer is set to false and vice
 	// versa. If the Soong config variable is not set then it defaults to false, so prefer defaults
 	// to true.
 	//
 	// If specified then the prefer property is ignored in favor of the value of the Soong config
 	// variable.
 	Use_source_config_var *ConfigVarProperties
 }

 // CopyUserSuppliedPropertiesFromPrebuilt copies the user supplied prebuilt properties from the
 // prebuilt properties.
 func (u *UserSuppliedPrebuiltProperties) CopyUserSuppliedPropertiesFromPrebuilt(p *Prebuilt) {
 	*u = p.properties.UserSuppliedPrebuiltProperties
 }

 type PrebuiltProperties struct {
 	UserSuppliedPrebuiltProperties

 	SourceExists bool `blueprint:"mutated"`
 	UsePrebuilt  bool `blueprint:"mutated"`

 	// Set if the module has been renamed to remove the "prebuilt_" prefix.
 	PrebuiltRenamedToSource bool `blueprint:"mutated"`
 }

 // Properties that can be used to select a Soong config variable.
 type ConfigVarProperties struct {
 	// Allow instances of this struct to be used as a property value in a BpPropertySet.
 	BpPrintableBase

 	// The name of the configuration namespace.
 	//
 	// As passed to add_soong_config_namespace in Make.
 	Config_namespace *string

 	// The name of the configuration variable.
 	//
 	// As passed to add_soong_config_var_value in Make.
 	Var_name *string
 }

 type Prebuilt struct {
 	properties PrebuiltProperties

 	// nil if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
 	srcsSupplier PrebuiltSrcsSupplier

 	// "-" if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
 	srcsPropertyName string
 }

 // RemoveOptionalPrebuiltPrefix returns the result of removing the "prebuilt_" prefix from the
 // supplied name if it has one, or returns the name unmodified if it does not.
 func RemoveOptionalPrebuiltPrefix(name string) string {
 	return strings.TrimPrefix(name, "prebuilt_")
 }

 func (p *Prebuilt) Name(name string) string {
 	return PrebuiltNameFromSource(name)
 }

 // PrebuiltNameFromSource returns the result of prepending the "prebuilt_" prefix to the supplied
 // name.
 func PrebuiltNameFromSource(name string) string {
 	return "prebuilt_" + name
 }

 func (p *Prebuilt) ForcePrefer() {
 	p.properties.Prefer = proptools.BoolPtr(true)
 }

 func (p *Prebuilt) Prefer() bool {
 	return proptools.Bool(p.properties.Prefer)
 }

 // SingleSourcePathFromSupplier invokes the supplied supplier for the current module in the
 // supplied context to retrieve a list of file paths, ensures that the returned list of file paths
 // contains a single value and then assumes that is a module relative file path and converts it to
 // a Path accordingly.
 //
 // Any issues, such as nil supplier or not exactly one file path will be reported as errors on the
 // supplied context and this will return nil.
 func SingleSourcePathFromSupplier(ctx ModuleContext, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) Path {
 	if srcsSupplier != nil {
 		srcs := srcsSupplier(ctx, ctx.Module())

 		if len(srcs) == 0 {
 			ctx.PropertyErrorf(srcsPropertyName, "missing prebuilt source file")
 			return nil
 		}

 		if len(srcs) > 1 {
 			ctx.PropertyErrorf(srcsPropertyName, "multiple prebuilt source files")
 			return nil
 		}

 		// Return the singleton source after expanding any filegroup in the
 		// sources.
 		src := srcs[0]
 		return PathForModuleSrc(ctx, src)
 	} else {
 		ctx.ModuleErrorf("prebuilt source was not set")
 		return nil
 	}
 }

 // The below source-related functions and the srcs, src fields are based on an assumption that
 // prebuilt modules have a static source property at the moment. Currently there is only one
 // exception, android_app_import, which chooses a source file depending on the product's DPI
 // preference configs. We'll want to add native support for dynamic source cases if we end up having
 // more modules like this.
 func (p *Prebuilt) SingleSourcePath(ctx ModuleContext) Path {
 	return SingleSourcePathFromSupplier(ctx, p.srcsSupplier, p.srcsPropertyName)
 }

 func (p *Prebuilt) UsePrebuilt() bool {
 	return p.properties.UsePrebuilt
 }

 // Called to provide the srcs value for the prebuilt module.
 //
 // This can be called with a context for any module not just the prebuilt one itself. It can also be
 // called concurrently.
 //
 // Return the src value or nil if it is not available.
 type PrebuiltSrcsSupplier func(ctx BaseModuleContext, prebuilt Module) []string

 func initPrebuiltModuleCommon(module PrebuiltInterface) *Prebuilt {
 	p := module.Prebuilt()
 	module.AddProperties(&p.properties)
 	return p
 }

 // Initialize the module as a prebuilt module that has no dedicated property that lists its
 // sources. SingleSourcePathFromSupplier should not be called for this module.
 //
 // This is the case e.g. for header modules, which provides the headers in source form
 // regardless whether they are prebuilt or not.
 func InitPrebuiltModuleWithoutSrcs(module PrebuiltInterface) {
 	p := initPrebuiltModuleCommon(module)
 	p.srcsPropertyName = "-"
 }

 // Initialize the module as a prebuilt module that uses the provided supplier to access the
 // prebuilt sources of the module.
 //
 // The supplier will be called multiple times and must return the same values each time it
 // is called. If it returns an empty array (or nil) then the prebuilt module will not be used
 // as a replacement for a source module with the same name even if prefer = true.
 //
 // If the Prebuilt.SingleSourcePath() is called on the module then this must return an array
 // containing exactly one source file.
 //
 // The provided property name is used to provide helpful error messages in the event that
 // a problem arises, e.g. calling SingleSourcePath() when more than one source is provided.
 func InitPrebuiltModuleWithSrcSupplier(module PrebuiltInterface, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) {
 	if srcsSupplier == nil {
 		panic(fmt.Errorf("srcsSupplier must not be nil"))
 	}
 	if srcsPropertyName == "" {
 		panic(fmt.Errorf("srcsPropertyName must not be empty"))
 	}

 	p := initPrebuiltModuleCommon(module)
 	p.srcsSupplier = srcsSupplier
 	p.srcsPropertyName = srcsPropertyName
 }

 func InitPrebuiltModule(module PrebuiltInterface, srcs *[]string) {
 	if srcs == nil {
 		panic(fmt.Errorf("srcs must not be nil"))
 	}

 	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
 		return *srcs
 	}

 	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, "srcs")
 }

 func InitSingleSourcePrebuiltModule(module PrebuiltInterface, srcProps interface{}, srcField string) {
 	srcPropsValue := reflect.ValueOf(srcProps).Elem()
 	srcStructField, _ := srcPropsValue.Type().FieldByName(srcField)
 	if !srcPropsValue.IsValid() || srcStructField.Name == "" {
 		panic(fmt.Errorf("invalid single source prebuilt %+v", module))
 	}

 	if srcPropsValue.Kind() != reflect.Struct && srcPropsValue.Kind() != reflect.Interface {
 		panic(fmt.Errorf("invalid single source prebuilt %+v", srcProps))
 	}

 	srcFieldIndex := srcStructField.Index
 	srcPropertyName := proptools.PropertyNameForField(srcField)

 	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
 		if !module.Enabled() {
 			return nil
 		}
 		value := srcPropsValue.FieldByIndex(srcFieldIndex)
 		if value.Kind() == reflect.Ptr {
 			value = value.Elem()
 		}
 		if value.Kind() != reflect.String {
 			panic(fmt.Errorf("prebuilt src field %q in %T in module %s should be a string or a pointer to one but was %v", srcField, srcProps, module, value))
 		}
 		src := value.String()
 		if src == "" {
 			return nil
 		}
 		return []string{src}
 	}

 	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, srcPropertyName)
 }

 type PrebuiltInterface interface {
 	Module
 	Prebuilt() *Prebuilt
 }

 // IsModulePreferred returns true if the given module is preferred.
 //
 // A source module is preferred if there is no corresponding prebuilt module or the prebuilt module
 // does not have "prefer: true".
 //
 // A prebuilt module is preferred if there is no corresponding source module or the prebuilt module
 // has "prefer: true".
 func IsModulePreferred(module Module) bool {
 	if module.IsReplacedByPrebuilt() {
 		// A source module that has been replaced by a prebuilt counterpart.
 		return false
 	}
 	if p := GetEmbeddedPrebuilt(module); p != nil {
 		return p.UsePrebuilt()
 	}
 	return true
 }

 // IsModulePrebuilt returns true if the module implements PrebuiltInterface and
 // has been initialized as a prebuilt and so returns a non-nil value from the
 // PrebuiltInterface.Prebuilt() method.
 func IsModulePrebuilt(module Module) bool {
 	return GetEmbeddedPrebuilt(module) != nil
 }

 // GetEmbeddedPrebuilt returns a pointer to the embedded Prebuilt structure or
 // nil if the module does not implement PrebuiltInterface or has not been
 // initialized as a prebuilt module.
 func GetEmbeddedPrebuilt(module Module) *Prebuilt {
 	if p, ok := module.(PrebuiltInterface); ok {
 		return p.Prebuilt()
 	}

 	return nil
 }

 // PrebuiltGetPreferred returns the module that is preferred for the given
 // module. That is either the module itself or the prebuilt counterpart that has
 // taken its place. The given module must be a direct dependency of the current
 // context module, and it must be the source module if both source and prebuilt
 // exist.
 //
 // This function is for use on dependencies after PrebuiltPostDepsMutator has
 // run - any dependency that is registered before that will already reference
 // the right module. This function is only safe to call after all mutators that
 // may call CreateVariations, e.g. in GenerateAndroidBuildActions.
 func PrebuiltGetPreferred(ctx BaseModuleContext, module Module) Module {
 	if !module.IsReplacedByPrebuilt() {
 		return module
 	}
 	if IsModulePrebuilt(module) {
 		// If we're given a prebuilt then assume there's no source module around.
 		return module
 	}

 	sourceModDepFound := false
 	var prebuiltMod Module

 	ctx.WalkDeps(func(child, parent Module) bool {
 		if prebuiltMod != nil {
 			return false
 		}
 		if parent == ctx.Module() {
 			// First level: Only recurse if the module is found as a direct dependency.
 			sourceModDepFound = child == module
 			return sourceModDepFound
 		}
 		// Second level: Follow PrebuiltDepTag to the prebuilt.
 		if t := ctx.OtherModuleDependencyTag(child); t == PrebuiltDepTag {
 			prebuiltMod = child
 		}
 		return false
 	})

 	if prebuiltMod == nil {
 		if !sourceModDepFound {
 			panic(fmt.Errorf("Failed to find source module as a direct dependency: %s", module))
 		} else {
 			panic(fmt.Errorf("Failed to find prebuilt for source module: %s", module))
 		}
 	}
 	return prebuiltMod
 }

 func RegisterPrebuiltsPreArchMutators(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("prebuilt_rename", PrebuiltRenameMutator).Parallel()
 }

 func RegisterPrebuiltsPostDepsMutators(ctx RegisterMutatorsContext) {
 	ctx.BottomUp("prebuilt_source", PrebuiltSourceDepsMutator).Parallel()
 	ctx.TopDown("prebuilt_select", PrebuiltSelectModuleMutator).Parallel()
 	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).Parallel()
 }

 // PrebuiltRenameMutator ensures that there always is a module with an
 // undecorated name.
 func PrebuiltRenameMutator(ctx BottomUpMutatorContext) {
 	m := ctx.Module()
 	if p := GetEmbeddedPrebuilt(m); p != nil {
 		name := m.base().BaseModuleName()
 		if !ctx.OtherModuleExists(name) {
 			ctx.Rename(name)
 			p.properties.PrebuiltRenamedToSource = true
 		}
 	}
 }

 // PrebuiltSourceDepsMutator adds dependencies to the prebuilt module from the
 // corresponding source module, if one exists for the same variant.
 func PrebuiltSourceDepsMutator(ctx BottomUpMutatorContext) {
 	m := ctx.Module()
 	// If this module is a prebuilt, is enabled and has not been renamed to source then add a
 	// dependency onto the source if it is present.
 	if p := GetEmbeddedPrebuilt(m); p != nil && m.Enabled() && !p.properties.PrebuiltRenamedToSource {
 		name := m.base().BaseModuleName()
 		if ctx.OtherModuleReverseDependencyVariantExists(name) {
 			ctx.AddReverseDependency(ctx.Module(), PrebuiltDepTag, name)
 			p.properties.SourceExists = true
 		}
 	}
 }

 // PrebuiltSelectModuleMutator marks prebuilts that are used, either overriding source modules or
 // because the source module doesn't exist.  It also disables installing overridden source modules.
 func PrebuiltSelectModuleMutator(ctx TopDownMutatorContext) {
 	m := ctx.Module()
 	if p := GetEmbeddedPrebuilt(m); p != nil {
 		if p.srcsSupplier == nil && p.srcsPropertyName == "" {
 			panic(fmt.Errorf("prebuilt module did not have InitPrebuiltModule called on it"))
 		}
 		if !p.properties.SourceExists {
 			p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil, m)
 		}
 	} else if s, ok := ctx.Module().(Module); ok {
 		ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(prebuiltModule Module) {
 			p := GetEmbeddedPrebuilt(prebuiltModule)
 			if p.usePrebuilt(ctx, s, prebuiltModule) {
 				p.properties.UsePrebuilt = true
 				s.ReplacedByPrebuilt()
 			}
 		})
 	}
 }

 // PrebuiltPostDepsMutator replaces dependencies on the source module with dependencies on the
 // prebuilt when both modules exist and the prebuilt should be used.  When the prebuilt should not
 // be used, disable installing it.
 func PrebuiltPostDepsMutator(ctx BottomUpMutatorContext) {
 	m := ctx.Module()
 	if p := GetEmbeddedPrebuilt(m); p != nil {
 		name := m.base().BaseModuleName()
 		if p.properties.UsePrebuilt {
 			if p.properties.SourceExists {
 				ctx.ReplaceDependenciesIf(name, func(from blueprint.Module, tag blueprint.DependencyTag, to blueprint.Module) bool {
 					if t, ok := tag.(ReplaceSourceWithPrebuilt); ok {
 						return t.ReplaceSourceWithPrebuilt()
 					}

 					return true
 				})
 			}
 		} else {
 			m.HideFromMake()
 		}
 	}
 }

 // usePrebuilt returns true if a prebuilt should be used instead of the source module.  The prebuilt
 // will be used if it is marked "prefer" or if the source module is disabled.
 func (p *Prebuilt) usePrebuilt(ctx TopDownMutatorContext, source Module, prebuilt Module) bool {
 	if p.srcsSupplier != nil && len(p.srcsSupplier(ctx, prebuilt)) == 0 {
 		return false
 	}

 	// Skip prebuilt modules under unexported namespaces so that we won't
 	// end up shadowing non-prebuilt module when prebuilt module under same
 	// name happens to have a `Prefer` property set to true.
 	if ctx.Config().KatiEnabled() && !prebuilt.ExportedToMake() {
 		return false
 	}

 	// If source is not available or is disabled then always use the prebuilt.
 	if source == nil || !source.Enabled() {
 		return true
 	}

 	// If the use_source_config_var property is set then it overrides the prefer property setting.
 	if configVar := p.properties.Use_source_config_var; configVar != nil {
 		return !ctx.Config().VendorConfig(proptools.String(configVar.Config_namespace)).Bool(proptools.String(configVar.Var_name))
 	}

 	// TODO: use p.Properties.Name and ctx.ModuleDir to override preference
 	return Bool(p.properties.Prefer)
 }

 func (p *Prebuilt) SourceExists() bool {
 	return p.properties.SourceExists
 }
	// 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 android

	import (
	"fmt"
	"reflect"
	"strings"

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

	// This file implements common functionality for handling modules that may exist as prebuilts,
	// source, or both.

	func RegisterPrebuiltMutators(ctx RegistrationContext) {
	ctx.PreArchMutators(RegisterPrebuiltsPreArchMutators)
	ctx.PostDepsMutators(RegisterPrebuiltsPostDepsMutators)
	}

	// Marks a dependency tag as possibly preventing a reference to a source from being
	// replaced with the prebuilt.
	type ReplaceSourceWithPrebuilt interface {
	blueprint.DependencyTag

	// Return true if the dependency defined by this tag should be replaced with the
	// prebuilt.
	ReplaceSourceWithPrebuilt() bool
	}

	type prebuiltDependencyTag struct {
	blueprint.BaseDependencyTag
	}

	var PrebuiltDepTag prebuiltDependencyTag

	// Mark this tag so dependencies that use it are excluded from visibility enforcement.
	func (t prebuiltDependencyTag) ExcludeFromVisibilityEnforcement() {}

	// Mark this tag so dependencies that use it are excluded from APEX contents.
	func (t prebuiltDependencyTag) ExcludeFromApexContents() {}

	var _ ExcludeFromVisibilityEnforcementTag = PrebuiltDepTag
	var _ ExcludeFromApexContentsTag = PrebuiltDepTag

	// UserSuppliedPrebuiltProperties contains the prebuilt properties that can be specified in an
	// Android.bp file.
	type UserSuppliedPrebuiltProperties struct {
	// When prefer is set to true the prebuilt will be used instead of any source module with
	// a matching name.
	Prefer *bool `android:"arch_variant"`

	// When specified this names a Soong config variable that controls the prefer property.
	//
	// If the value of the named Soong config variable is true then prefer is set to false and vice
	// versa. If the Soong config variable is not set then it defaults to false, so prefer defaults
	// to true.
	//
	// If specified then the prefer property is ignored in favor of the value of the Soong config
	// variable.
	Use_source_config_var *ConfigVarProperties
	}

	// CopyUserSuppliedPropertiesFromPrebuilt copies the user supplied prebuilt properties from the
	// prebuilt properties.
	func (u UserSuppliedPrebuiltProperties) CopyUserSuppliedPropertiesFromPrebuilt(p Prebuilt) {
	*u = p.properties.UserSuppliedPrebuiltProperties
	}

	type PrebuiltProperties struct {
	UserSuppliedPrebuiltProperties

	SourceExists bool `blueprint:"mutated"`
	UsePrebuilt bool `blueprint:"mutated"`

	// Set if the module has been renamed to remove the "prebuilt_" prefix.
	PrebuiltRenamedToSource bool `blueprint:"mutated"`
	}

	// Properties that can be used to select a Soong config variable.
	type ConfigVarProperties struct {
	// Allow instances of this struct to be used as a property value in a BpPropertySet.
	BpPrintableBase

	// The name of the configuration namespace.
	//
	// As passed to add_soong_config_namespace in Make.
	Config_namespace *string

	// The name of the configuration variable.
	//
	// As passed to add_soong_config_var_value in Make.
	Var_name *string
	}

	type Prebuilt struct {
	properties PrebuiltProperties

	// nil if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
	srcsSupplier PrebuiltSrcsSupplier

	// "-" if the prebuilt has no srcs property at all. See InitPrebuiltModuleWithoutSrcs.
	srcsPropertyName string
	}

	// RemoveOptionalPrebuiltPrefix returns the result of removing the "prebuilt_" prefix from the
	// supplied name if it has one, or returns the name unmodified if it does not.
	func RemoveOptionalPrebuiltPrefix(name string) string {
	return strings.TrimPrefix(name, "prebuilt_")
	}

	func (p *Prebuilt) Name(name string) string {
	return PrebuiltNameFromSource(name)
	}

	// PrebuiltNameFromSource returns the result of prepending the "prebuilt_" prefix to the supplied
	// name.
	func PrebuiltNameFromSource(name string) string {
	return "prebuilt_" + name
	}

	func (p *Prebuilt) ForcePrefer() {
	p.properties.Prefer = proptools.BoolPtr(true)
	}

	func (p *Prebuilt) Prefer() bool {
	return proptools.Bool(p.properties.Prefer)
	}

	// SingleSourcePathFromSupplier invokes the supplied supplier for the current module in the
	// supplied context to retrieve a list of file paths, ensures that the returned list of file paths
	// contains a single value and then assumes that is a module relative file path and converts it to
	// a Path accordingly.
	//
	// Any issues, such as nil supplier or not exactly one file path will be reported as errors on the
	// supplied context and this will return nil.
	func SingleSourcePathFromSupplier(ctx ModuleContext, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) Path {
	if srcsSupplier != nil {
	srcs := srcsSupplier(ctx, ctx.Module())

	if len(srcs) == 0 {
	ctx.PropertyErrorf(srcsPropertyName, "missing prebuilt source file")
	return nil
	}

	if len(srcs) > 1 {
	ctx.PropertyErrorf(srcsPropertyName, "multiple prebuilt source files")
	return nil
	}

	// Return the singleton source after expanding any filegroup in the
	// sources.
	src := srcs[0]
	return PathForModuleSrc(ctx, src)
	} else {
	ctx.ModuleErrorf("prebuilt source was not set")
	return nil
	}
	}

	// The below source-related functions and the srcs, src fields are based on an assumption that
	// prebuilt modules have a static source property at the moment. Currently there is only one
	// exception, android_app_import, which chooses a source file depending on the product's DPI
	// preference configs. We'll want to add native support for dynamic source cases if we end up having
	// more modules like this.
	func (p *Prebuilt) SingleSourcePath(ctx ModuleContext) Path {
	return SingleSourcePathFromSupplier(ctx, p.srcsSupplier, p.srcsPropertyName)
	}

	func (p *Prebuilt) UsePrebuilt() bool {
	return p.properties.UsePrebuilt
	}

	// Called to provide the srcs value for the prebuilt module.
	//
	// This can be called with a context for any module not just the prebuilt one itself. It can also be
	// called concurrently.
	//
	// Return the src value or nil if it is not available.
	type PrebuiltSrcsSupplier func(ctx BaseModuleContext, prebuilt Module) []string

	func initPrebuiltModuleCommon(module PrebuiltInterface) *Prebuilt {
	p := module.Prebuilt()
	module.AddProperties(&p.properties)
	return p
	}

	// Initialize the module as a prebuilt module that has no dedicated property that lists its
	// sources. SingleSourcePathFromSupplier should not be called for this module.
	//
	// This is the case e.g. for header modules, which provides the headers in source form
	// regardless whether they are prebuilt or not.
	func InitPrebuiltModuleWithoutSrcs(module PrebuiltInterface) {
	p := initPrebuiltModuleCommon(module)
	p.srcsPropertyName = "-"
	}

	// Initialize the module as a prebuilt module that uses the provided supplier to access the
	// prebuilt sources of the module.
	//
	// The supplier will be called multiple times and must return the same values each time it
	// is called. If it returns an empty array (or nil) then the prebuilt module will not be used
	// as a replacement for a source module with the same name even if prefer = true.
	//
	// If the Prebuilt.SingleSourcePath() is called on the module then this must return an array
	// containing exactly one source file.
	//
	// The provided property name is used to provide helpful error messages in the event that
	// a problem arises, e.g. calling SingleSourcePath() when more than one source is provided.
	func InitPrebuiltModuleWithSrcSupplier(module PrebuiltInterface, srcsSupplier PrebuiltSrcsSupplier, srcsPropertyName string) {
	if srcsSupplier == nil {
	panic(fmt.Errorf("srcsSupplier must not be nil"))
	}
	if srcsPropertyName == "" {
	panic(fmt.Errorf("srcsPropertyName must not be empty"))
	}

	p := initPrebuiltModuleCommon(module)
	p.srcsSupplier = srcsSupplier
	p.srcsPropertyName = srcsPropertyName
	}

	func InitPrebuiltModule(module PrebuiltInterface, srcs *[]string) {
	if srcs == nil {
	panic(fmt.Errorf("srcs must not be nil"))
	}

	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
	return *srcs
	}

	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, "srcs")
	}

	func InitSingleSourcePrebuiltModule(module PrebuiltInterface, srcProps interface{}, srcField string) {
	srcPropsValue := reflect.ValueOf(srcProps).Elem()
	srcStructField, _ := srcPropsValue.Type().FieldByName(srcField)
	if !srcPropsValue.IsValid() \|\| srcStructField.Name == "" {
	panic(fmt.Errorf("invalid single source prebuilt %+v", module))
	}

	if srcPropsValue.Kind() != reflect.Struct && srcPropsValue.Kind() != reflect.Interface {
	panic(fmt.Errorf("invalid single source prebuilt %+v", srcProps))
	}

	srcFieldIndex := srcStructField.Index
	srcPropertyName := proptools.PropertyNameForField(srcField)

	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
	if !module.Enabled() {
	return nil
	}
	value := srcPropsValue.FieldByIndex(srcFieldIndex)
	if value.Kind() == reflect.Ptr {
	value = value.Elem()
	}
	if value.Kind() != reflect.String {
	panic(fmt.Errorf("prebuilt src field %q in %T in module %s should be a string or a pointer to one but was %v", srcField, srcProps, module, value))
	}
	src := value.String()
	if src == "" {
	return nil
	}
	return []string{src}
	}

	InitPrebuiltModuleWithSrcSupplier(module, srcsSupplier, srcPropertyName)
	}

	type PrebuiltInterface interface {
	Module
	Prebuilt() *Prebuilt
	}

	// IsModulePreferred returns true if the given module is preferred.
	//
	// A source module is preferred if there is no corresponding prebuilt module or the prebuilt module
	// does not have "prefer: true".
	//
	// A prebuilt module is preferred if there is no corresponding source module or the prebuilt module
	// has "prefer: true".
	func IsModulePreferred(module Module) bool {
	if module.IsReplacedByPrebuilt() {
	// A source module that has been replaced by a prebuilt counterpart.
	return false
	}
	if p := GetEmbeddedPrebuilt(module); p != nil {
	return p.UsePrebuilt()
	}
	return true
	}

	// IsModulePrebuilt returns true if the module implements PrebuiltInterface and
	// has been initialized as a prebuilt and so returns a non-nil value from the
	// PrebuiltInterface.Prebuilt() method.
	func IsModulePrebuilt(module Module) bool {
	return GetEmbeddedPrebuilt(module) != nil
	}

	// GetEmbeddedPrebuilt returns a pointer to the embedded Prebuilt structure or
	// nil if the module does not implement PrebuiltInterface or has not been
	// initialized as a prebuilt module.
	func GetEmbeddedPrebuilt(module Module) *Prebuilt {
	if p, ok := module.(PrebuiltInterface); ok {
	return p.Prebuilt()
	}

	return nil
	}

	// PrebuiltGetPreferred returns the module that is preferred for the given
	// module. That is either the module itself or the prebuilt counterpart that has
	// taken its place. The given module must be a direct dependency of the current
	// context module, and it must be the source module if both source and prebuilt
	// exist.
	//
	// This function is for use on dependencies after PrebuiltPostDepsMutator has
	// run - any dependency that is registered before that will already reference
	// the right module. This function is only safe to call after all mutators that
	// may call CreateVariations, e.g. in GenerateAndroidBuildActions.
	func PrebuiltGetPreferred(ctx BaseModuleContext, module Module) Module {
	if !module.IsReplacedByPrebuilt() {
	return module
	}
	if IsModulePrebuilt(module) {
	// If we're given a prebuilt then assume there's no source module around.
	return module
	}

	sourceModDepFound := false
	var prebuiltMod Module

	ctx.WalkDeps(func(child, parent Module) bool {
	if prebuiltMod != nil {
	return false
	}
	if parent == ctx.Module() {
	// First level: Only recurse if the module is found as a direct dependency.
	sourceModDepFound = child == module
	return sourceModDepFound
	}
	// Second level: Follow PrebuiltDepTag to the prebuilt.
	if t := ctx.OtherModuleDependencyTag(child); t == PrebuiltDepTag {
	prebuiltMod = child
	}
	return false
	})

	if prebuiltMod == nil {
	if !sourceModDepFound {
	panic(fmt.Errorf("Failed to find source module as a direct dependency: %s", module))
	} else {
	panic(fmt.Errorf("Failed to find prebuilt for source module: %s", module))
	}
	}
	return prebuiltMod
	}

	func RegisterPrebuiltsPreArchMutators(ctx RegisterMutatorsContext) {
	ctx.BottomUp("prebuilt_rename", PrebuiltRenameMutator).Parallel()
	}

	func RegisterPrebuiltsPostDepsMutators(ctx RegisterMutatorsContext) {
	ctx.BottomUp("prebuilt_source", PrebuiltSourceDepsMutator).Parallel()
	ctx.TopDown("prebuilt_select", PrebuiltSelectModuleMutator).Parallel()
	ctx.BottomUp("prebuilt_postdeps", PrebuiltPostDepsMutator).Parallel()
	}

	// PrebuiltRenameMutator ensures that there always is a module with an
	// undecorated name.
	func PrebuiltRenameMutator(ctx BottomUpMutatorContext) {
	m := ctx.Module()
	if p := GetEmbeddedPrebuilt(m); p != nil {
	name := m.base().BaseModuleName()
	if !ctx.OtherModuleExists(name) {
	ctx.Rename(name)
	p.properties.PrebuiltRenamedToSource = true
	}
	}
	}

	// PrebuiltSourceDepsMutator adds dependencies to the prebuilt module from the
	// corresponding source module, if one exists for the same variant.
	func PrebuiltSourceDepsMutator(ctx BottomUpMutatorContext) {
	m := ctx.Module()
	// If this module is a prebuilt, is enabled and has not been renamed to source then add a
	// dependency onto the source if it is present.
	if p := GetEmbeddedPrebuilt(m); p != nil && m.Enabled() && !p.properties.PrebuiltRenamedToSource {
	name := m.base().BaseModuleName()
	if ctx.OtherModuleReverseDependencyVariantExists(name) {
	ctx.AddReverseDependency(ctx.Module(), PrebuiltDepTag, name)
	p.properties.SourceExists = true
	}
	}
	}

	// PrebuiltSelectModuleMutator marks prebuilts that are used, either overriding source modules or
	// because the source module doesn't exist. It also disables installing overridden source modules.
	func PrebuiltSelectModuleMutator(ctx TopDownMutatorContext) {
	m := ctx.Module()
	if p := GetEmbeddedPrebuilt(m); p != nil {
	if p.srcsSupplier == nil && p.srcsPropertyName == "" {
	panic(fmt.Errorf("prebuilt module did not have InitPrebuiltModule called on it"))
	}
	if !p.properties.SourceExists {
	p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil, m)
	}
	} else if s, ok := ctx.Module().(Module); ok {
	ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(prebuiltModule Module) {
	p := GetEmbeddedPrebuilt(prebuiltModule)
	if p.usePrebuilt(ctx, s, prebuiltModule) {
	p.properties.UsePrebuilt = true
	s.ReplacedByPrebuilt()
	}
	})
	}
	}

	// PrebuiltPostDepsMutator replaces dependencies on the source module with dependencies on the
	// prebuilt when both modules exist and the prebuilt should be used. When the prebuilt should not
	// be used, disable installing it.
	func PrebuiltPostDepsMutator(ctx BottomUpMutatorContext) {
	m := ctx.Module()
	if p := GetEmbeddedPrebuilt(m); p != nil {
	name := m.base().BaseModuleName()
	if p.properties.UsePrebuilt {
	if p.properties.SourceExists {
	ctx.ReplaceDependenciesIf(name, func(from blueprint.Module, tag blueprint.DependencyTag, to blueprint.Module) bool {
	if t, ok := tag.(ReplaceSourceWithPrebuilt); ok {
	return t.ReplaceSourceWithPrebuilt()
	}

	return true
	})
	}
	} else {
	m.HideFromMake()
	}
	}
	}

	// usePrebuilt returns true if a prebuilt should be used instead of the source module. The prebuilt
	// will be used if it is marked "prefer" or if the source module is disabled.
	func (p *Prebuilt) usePrebuilt(ctx TopDownMutatorContext, source Module, prebuilt Module) bool {
	if p.srcsSupplier != nil && len(p.srcsSupplier(ctx, prebuilt)) == 0 {
	return false
	}

	// Skip prebuilt modules under unexported namespaces so that we won't
	// end up shadowing non-prebuilt module when prebuilt module under same
	// name happens to have a `Prefer` property set to true.
	if ctx.Config().KatiEnabled() && !prebuilt.ExportedToMake() {
	return false
	}

	// If source is not available or is disabled then always use the prebuilt.
	if source == nil \|\| !source.Enabled() {
	return true
	}

	// If the use_source_config_var property is set then it overrides the prefer property setting.
	if configVar := p.properties.Use_source_config_var; configVar != nil {
	return !ctx.Config().VendorConfig(proptools.String(configVar.Config_namespace)).Bool(proptools.String(configVar.Var_name))
	}

	// TODO: use p.Properties.Name and ctx.ModuleDir to override preference
	return Bool(p.properties.Prefer)
	}

	func (p *Prebuilt) SourceExists() bool {
	return p.properties.SourceExists
	}