Add filegroup_defaults module

Allows specifying shared filegroup attributes in a central place.

Test: filegroup_test.go
Change-Id: I82feac37ae6998313a0004f8af58f3decf7a514e
(cherry picked from https://android-review.googlesource.com/q/commit:7d6dd8bb3324e81b5c4afc80b062baad2fed1770)
Merged-In: I82feac37ae6998313a0004f8af58f3decf7a514e

android/filegroup.go

@@ -23,13 +23,18 @@ import (
 )
 
 func init() {
-	RegisterModuleType("filegroup", FileGroupFactory)
+	RegisterFilegroupBuildComponents(InitRegistrationContext)
 }
 
 var PrepareForTestWithFilegroup = FixtureRegisterWithContext(func(ctx RegistrationContext) {
-	ctx.RegisterModuleType("filegroup", FileGroupFactory)
+	RegisterFilegroupBuildComponents(ctx)
 })
 
+func RegisterFilegroupBuildComponents(ctx RegistrationContext) {
+	ctx.RegisterModuleType("filegroup", FileGroupFactory)
+	ctx.RegisterModuleType("filegroup_defaults", FileGroupDefaultsFactory)
+}
+
 // IsFilegroup checks that a module is a filegroup type
 func IsFilegroup(ctx bazel.OtherModuleContext, m blueprint.Module) bool {
 	return ctx.OtherModuleType(m) == "filegroup"
@@ -97,6 +102,7 @@ type fileGroupProperties struct {
 type fileGroup struct {
 	ModuleBase
 	BazelModuleBase
+	DefaultableModuleBase
 	properties fileGroupProperties
 	srcs       Paths
 }
@@ -111,6 +117,7 @@ func FileGroupFactory() Module {
 	module.AddProperties(&module.properties)
 	InitAndroidModule(module)
 	InitBazelModule(module)
+	InitDefaultableModule(module)
 	return module
 }
 
@@ -161,3 +168,17 @@ func (fg *fileGroup) MakeVars(ctx MakeVarsModuleContext) {
 		ctx.StrictRaw(makeVar, strings.Join(fg.srcs.Strings(), " "))
 	}
 }
+
+// Defaults
+type FileGroupDefaults struct {
+	ModuleBase
+	DefaultsModuleBase
+}
+
+func FileGroupDefaultsFactory() Module {
+	module := &FileGroupDefaults{}
+	module.AddProperties(&fileGroupProperties{})
+	InitDefaultsModule(module)
+
+	return module
+}

android/filegroup_test.go

@@ -0,0 +1,26 @@
+package android
+
+import (
+	"testing"
+)
+
+func TestFilegroupDefaults(t *testing.T) {
+	bp := FixtureAddTextFile("p/Android.bp", `
+		filegroup_defaults {
+			name: "defaults",
+			visibility: ["//x"],
+		}
+		filegroup {
+			name: "foo",
+			defaults: ["defaults"],
+			visibility: ["//y"],
+		}
+	`)
+	result := GroupFixturePreparers(
+		PrepareForTestWithFilegroup,
+		PrepareForTestWithDefaults,
+		PrepareForTestWithVisibility,
+		bp).RunTest(t)
+	rules := effectiveVisibilityRules(result.Config, qualifiedModuleName{pkg: "p", name: "foo"})
+	AssertDeepEquals(t, "visibility", []string{"//x", "//y"}, rules.Strings())
+}