Add container property to aconfig_declarations.

Bug: 311155208
Test: Unit test
Change-Id: I7b187138856d0144203961e82b6dad5e2f8eed9d
diff --git a/aconfig/codegen/rust_aconfig_library.go b/aconfig/codegen/rust_aconfig_library.go
new file mode 100644
index 0000000..3525de1
--- /dev/null
+++ b/aconfig/codegen/rust_aconfig_library.go
@@ -0,0 +1,97 @@
+package codegen
+
+import (
+	"fmt"
+
+	"android/soong/aconfig"
+	"android/soong/android"
+	"android/soong/rust"
+
+	"github.com/google/blueprint"
+	"github.com/google/blueprint/proptools"
+)
+
+type rustDeclarationsTagType struct {
+	blueprint.BaseDependencyTag
+}
+
+var rustDeclarationsTag = rustDeclarationsTagType{}
+
+type RustAconfigLibraryProperties struct {
+	// name of the aconfig_declarations module to generate a library for
+	Aconfig_declarations string
+
+	// default mode is "production", the other accepted modes are:
+	// "test": to generate test mode version of the library
+	// "exported": to generate exported mode version of the library
+	// an error will be thrown if the mode is not supported
+	Mode *string
+}
+
+type aconfigDecorator struct {
+	*rust.BaseSourceProvider
+
+	Properties RustAconfigLibraryProperties
+}
+
+func NewRustAconfigLibrary(hod android.HostOrDeviceSupported) (*rust.Module, *aconfigDecorator) {
+	aconfig := &aconfigDecorator{
+		BaseSourceProvider: rust.NewSourceProvider(),
+		Properties:         RustAconfigLibraryProperties{},
+	}
+
+	module := rust.NewSourceProviderModule(android.HostAndDeviceSupported, aconfig, false, false)
+	return module, aconfig
+}
+
+// rust_aconfig_library generates aconfig rust code from the provided aconfig declaration. This module type will
+// create library variants that can be used as a crate dependency by adding it to the rlibs, dylibs, and rustlibs
+// properties of other modules.
+func RustAconfigLibraryFactory() android.Module {
+	module, _ := NewRustAconfigLibrary(android.HostAndDeviceSupported)
+	return module.Init()
+}
+
+func (a *aconfigDecorator) SourceProviderProps() []interface{} {
+	return append(a.BaseSourceProvider.SourceProviderProps(), &a.Properties)
+}
+
+func (a *aconfigDecorator) GenerateSource(ctx rust.ModuleContext, deps rust.PathDeps) android.Path {
+	generatedDir := android.PathForModuleGen(ctx)
+	generatedSource := android.PathForModuleGen(ctx, "src", "lib.rs")
+
+	declarationsModules := ctx.GetDirectDepsWithTag(rustDeclarationsTag)
+
+	if len(declarationsModules) != 1 {
+		panic(fmt.Errorf("Exactly one aconfig_declarations property required"))
+	}
+	declarations := ctx.OtherModuleProvider(declarationsModules[0], aconfig.DeclarationsProviderKey).(aconfig.DeclarationsProviderData)
+
+	mode := proptools.StringDefault(a.Properties.Mode, "production")
+	if !isModeSupported(mode) {
+		ctx.PropertyErrorf("mode", "%q is not a supported mode", mode)
+	}
+
+	ctx.Build(pctx, android.BuildParams{
+		Rule:  rustRule,
+		Input: declarations.IntermediatePath,
+		Outputs: []android.WritablePath{
+			generatedSource,
+		},
+		Description: "rust_aconfig_library",
+		Args: map[string]string{
+			"gendir": generatedDir.String(),
+			"mode":   mode,
+		},
+	})
+	a.BaseSourceProvider.OutputFiles = android.Paths{generatedSource}
+	return generatedSource
+}
+
+func (a *aconfigDecorator) SourceProviderDeps(ctx rust.DepsContext, deps rust.Deps) rust.Deps {
+	deps = a.BaseSourceProvider.SourceProviderDeps(ctx, deps)
+	deps.Rustlibs = append(deps.Rustlibs, "libflags_rust")
+	deps.Rustlibs = append(deps.Rustlibs, "liblazy_static")
+	ctx.AddDependency(ctx.Module(), rustDeclarationsTag, a.Properties.Aconfig_declarations)
+	return deps
+}