Remove deapexer and prebuilt apex select mutators

Originally, when the prebuilt_apex was first created, it selected the
source to use in its DepsMutator. It did that because that was a
convenient place for it to perform that work which had to be:
* After the arch mutator had run so MultiTargets() was available.
* Before the prebuilt_select mutator runs as that relied on the Source
  property to have been set.

Change 064b70c9 then duplicated the call from the DepsMutator of the
deapexer module type that was added as part of the work to make dex
files available for hiddenapi processing.

Change 356f7d45 moved it out of the the DepsMutator methods into its
their own mutators, presumably because it interfered with the
Soong -> Bazel conversion work.

This change improves the existing PrebuiltSrcsSupplier mechanism to
support reporting errors so that the logic for selecting the source can
be done on demand rather than in separate mutators.

The main complication was that PrebuiltSrcsSupplier is called with a
BaseModuleContext for both source and prebuilt modules so it cannot use
any methods on it that are related to the current module. That
necessitated adding MultiTargets() to android.Module.

Bug: 181267622
Test: m droid
Change-Id: I106c78fd21016f051a315b82b470d8f12b1f820b

android/module.go

@@ -443,6 +443,7 @@ type Module interface {
 	Disable()
 	Enabled() bool
 	Target() Target
+	MultiTargets() []Target
 	Owner() string
 	InstallInData() bool
 	InstallInTestcases() bool

android/prebuilt.go

@@ -100,7 +100,7 @@ func (p *Prebuilt) Prefer() bool {
 // more modules like this.
 func (p *Prebuilt) SingleSourcePath(ctx ModuleContext) Path {
 	if p.srcsSupplier != nil {
-		srcs := p.srcsSupplier(ctx)
+		srcs := p.srcsSupplier(ctx, ctx.Module())
 
 		if len(srcs) == 0 {
 			ctx.PropertyErrorf(p.srcsPropertyName, "missing prebuilt source file")
@@ -128,8 +128,11 @@ func (p *Prebuilt) UsePrebuilt() bool {
 
 // 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) []string
+type PrebuiltSrcsSupplier func(ctx BaseModuleContext, prebuilt Module) []string
 
 // Initialize the module as a prebuilt module that uses the provided supplier to access the
 // prebuilt sources of the module.
@@ -163,7 +166,7 @@ func InitPrebuiltModule(module PrebuiltInterface, srcs *[]string) {
 		panic(fmt.Errorf("srcs must not be nil"))
 	}
 
-	srcsSupplier := func(ctx BaseModuleContext) []string {
+	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
 		return *srcs
 	}
 
@@ -184,7 +187,7 @@ func InitSingleSourcePrebuiltModule(module PrebuiltInterface, srcProps interface
 	srcFieldIndex := srcStructField.Index
 	srcPropertyName := proptools.PropertyNameForField(srcField)
 
-	srcsSupplier := func(ctx BaseModuleContext) []string {
+	srcsSupplier := func(ctx BaseModuleContext, _ Module) []string {
 		if !module.Enabled() {
 			return nil
 		}
@@ -256,12 +259,12 @@ func PrebuiltSelectModuleMutator(ctx TopDownMutatorContext) {
 			panic(fmt.Errorf("prebuilt module did not have InitPrebuiltModule called on it"))
 		}
 		if !p.properties.SourceExists {
-			p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil)
+			p.properties.UsePrebuilt = p.usePrebuilt(ctx, nil, m)
 		}
 	} else if s, ok := ctx.Module().(Module); ok {
 		ctx.VisitDirectDepsWithTag(PrebuiltDepTag, func(m Module) {
 			p := m.(PrebuiltInterface).Prebuilt()
-			if p.usePrebuilt(ctx, s) {
+			if p.usePrebuilt(ctx, s, m) {
 				p.properties.UsePrebuilt = true
 				s.ReplacedByPrebuilt()
 			}
@@ -296,8 +299,8 @@ func PrebuiltPostDepsMutator(ctx BottomUpMutatorContext) {
 
 // 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) bool {
-	if p.srcsSupplier != nil && len(p.srcsSupplier(ctx)) == 0 {
+func (p *Prebuilt) usePrebuilt(ctx TopDownMutatorContext, source Module, prebuilt Module) bool {
+	if p.srcsSupplier != nil && len(p.srcsSupplier(ctx, prebuilt)) == 0 {
 		return false
 	}
 

apex/apex.go

@@ -54,8 +54,6 @@ func init() {
 func RegisterPreDepsMutators(ctx android.RegisterMutatorsContext) {
 	ctx.TopDown("apex_vndk", apexVndkMutator).Parallel()
 	ctx.BottomUp("apex_vndk_deps", apexVndkDepsMutator).Parallel()
-	ctx.BottomUp("prebuilt_apex_select_source", prebuiltSelectSourceMutator).Parallel()
-	ctx.BottomUp("deapexer_select_source", deapexerSelectSourceMutator).Parallel()
 }
 
 func RegisterPostDepsMutators(ctx android.RegisterMutatorsContext) {

apex/deapexer.go

@@ -65,7 +65,7 @@ func privateDeapexerFactory() android.Module {
 		&module.properties,
 		&module.apexFileProperties,
 	)
-	android.InitSingleSourcePrebuiltModule(module, &module.apexFileProperties, "Source")
+	android.InitPrebuiltModuleWithSrcSupplier(module, module.apexFileProperties.prebuiltApexSelector, "src")
 	android.InitAndroidMultiTargetsArchModule(module, android.DeviceSupported, android.MultilibCommon)
 	return module
 }
@@ -78,16 +78,6 @@ func (p *Deapexer) Name() string {
 	return p.prebuilt.Name(p.ModuleBase.Name())
 }
 
-func deapexerSelectSourceMutator(ctx android.BottomUpMutatorContext) {
-	p, ok := ctx.Module().(*Deapexer)
-	if !ok {
-		return
-	}
-	if err := p.apexFileProperties.selectSource(ctx); err != nil {
-		ctx.ModuleErrorf("%s", err)
-	}
-}
-
 func (p *Deapexer) DepsMutator(ctx android.BottomUpMutatorContext) {
 	// Add dependencies from the java modules to which this exports files from the `.apex` file onto
 	// this module so that they can access the `DeapexerInfo` object that this provides.

apex/prebuilt.go

@@ -109,8 +109,10 @@ type Prebuilt struct {
 
 type ApexFileProperties struct {
 	// the path to the prebuilt .apex file to import.
-	Source string `blueprint:"mutated"`
-
+	//
+	// This cannot be marked as `android:"arch_variant"` because the `prebuilt_apex` is only mutated
+	// for android_common. That is so that it will have the same arch variant as, and so be compatible
+	// with, the source `apex` module type that it replaces.
 	Src  *string
 	Arch struct {
 		Arm struct {
@@ -128,15 +130,20 @@ type ApexFileProperties struct {
 	}
 }
 
-func (p *ApexFileProperties) selectSource(ctx android.BottomUpMutatorContext) error {
-	// 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 {
-		return fmt.Errorf("compile_multilib shouldn't be \"both\" for prebuilt_apex")
+// prebuiltApexSelector selects the correct prebuilt APEX file for the build target.
+//
+// The ctx parameter can be for any module not just the prebuilt module so care must be taken not
+// to use methods on it that are specific to the current module.
+//
+// See the ApexFileProperties.Src property.
+func (p *ApexFileProperties) prebuiltApexSelector(ctx android.BaseModuleContext, prebuilt android.Module) []string {
+	multiTargets := prebuilt.MultiTargets()
+	if len(multiTargets) != 1 {
+		ctx.OtherModuleErrorf(prebuilt, "compile_multilib shouldn't be \"both\" for prebuilt_apex")
+		return nil
 	}
 	var src string
-	switch ctx.MultiTargets()[0].Arch.ArchType {
+	switch multiTargets[0].Arch.ArchType {
 	case android.Arm:
 		src = String(p.Arch.Arm.Src)
 	case android.Arm64:
@@ -146,14 +153,14 @@ func (p *ApexFileProperties) selectSource(ctx android.BottomUpMutatorContext) er
 	case android.X86_64:
 		src = String(p.Arch.X86_64.Src)
 	default:
-		return fmt.Errorf("prebuilt_apex does not support %q", ctx.MultiTargets()[0].Arch.String())
+		ctx.OtherModuleErrorf(prebuilt, "prebuilt_apex does not support %q", multiTargets[0].Arch.String())
+		return nil
 	}
 	if src == "" {
 		src = String(p.Src)
 	}
-	p.Source = src
 
-	return nil
+	return []string{src}
 }
 
 type PrebuiltProperties struct {
@@ -217,7 +224,7 @@ func (p *Prebuilt) Name() string {
 func PrebuiltFactory() android.Module {
 	module := &Prebuilt{}
 	module.AddProperties(&module.properties)
-	android.InitSingleSourcePrebuiltModule(module, &module.properties, "Source")
+	android.InitPrebuiltModuleWithSrcSupplier(module, module.properties.prebuiltApexSelector, "src")
 	android.InitAndroidMultiTargetsArchModule(module, android.DeviceSupported, android.MultilibCommon)
 
 	android.AddLoadHook(module, func(ctx android.LoadHookContext) {
@@ -250,16 +257,6 @@ func prebuiltApexExportedModuleName(ctx android.BottomUpMutatorContext, name str
 	return name
 }
 
-func prebuiltSelectSourceMutator(ctx android.BottomUpMutatorContext) {
-	p, ok := ctx.Module().(*Prebuilt)
-	if !ok {
-		return
-	}
-	if err := p.properties.selectSource(ctx); err != nil {
-		ctx.ModuleErrorf("%s", err)
-	}
-}
-
 type exportedDependencyTag struct {
 	blueprint.BaseDependencyTag
 	name string
@@ -535,7 +532,7 @@ func apexSetFactory() android.Module {
 	module := &ApexSet{}
 	module.AddProperties(&module.properties)
 
-	srcsSupplier := func(ctx android.BaseModuleContext) []string {
+	srcsSupplier := func(ctx android.BaseModuleContext, _ android.Module) []string {
 		return module.prebuiltSrcs(ctx)
 	}
 

cc/prebuilt.go

@@ -246,7 +246,7 @@ func NewPrebuiltLibrary(hod android.HostOrDeviceSupported) (*Module, *libraryDec
 
 	module.AddProperties(&prebuilt.properties)
 
-	srcsSupplier := func(ctx android.BaseModuleContext) []string {
+	srcsSupplier := func(ctx android.BaseModuleContext, _ android.Module) []string {
 		return prebuilt.prebuiltSrcs(ctx)
 	}