Add support for python_defaults modules

Test: python_test.go
Change-Id: I2077414a5b06da5e660a1b48bfdb2eb926fb702f

Android.bp

@@ -238,6 +238,7 @@ bootstrap_go_package {
         "python/androidmk.go",
         "python/binary.go",
         "python/builder.go",
+        "python/defaults.go",
         "python/installer.go",
         "python/library.go",
         "python/python.go",

python/defaults.go

@@ -0,0 +1,51 @@
+// Copyright 2017 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 python
+
+import (
+	"android/soong/android"
+)
+
+func init() {
+	android.RegisterModuleType("python_defaults", defaultsFactory)
+}
+
+type Defaults struct {
+	android.ModuleBase
+	android.DefaultsModuleBase
+}
+
+func (d *Defaults) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+}
+
+func (d *Defaults) DepsMutator(ctx android.BottomUpMutatorContext) {
+}
+
+func defaultsFactory() android.Module {
+	return DefaultsFactory()
+}
+
+func DefaultsFactory(props ...interface{}) android.Module {
+	module := &Defaults{}
+
+	module.AddProperties(props...)
+	module.AddProperties(
+		&BaseProperties{},
+	)
+
+	android.InitDefaultsModule(module)
+
+	return module
+}

python/python.go

@@ -109,6 +109,7 @@ type pathMapping struct {
 
 type Module struct {
 	android.ModuleBase
+	android.DefaultableModuleBase
 
 	properties BaseProperties
 
@@ -194,6 +195,7 @@ func (p *Module) Init() android.Module {
 	}
 
 	android.InitAndroidArchModule(p, p.hod, p.multilib)
+	android.InitDefaultableModule(p)
 
 	return p
 }

python/python_test.go

@@ -222,7 +222,28 @@ var (
 			mockFiles: map[string][]byte{
 				bpFile: []byte(`subdirs = ["dir"]`),
 				filepath.Join("dir", bpFile): []byte(
-					`python_library_host {
+					`python_defaults {
+						name: "default_lib",
+						srcs: [
+							"default.py",
+						],
+						version: {
+							py2: {
+								enabled: true,
+								srcs: [
+									"default_py2.py",
+								],
+							},
+							py3: {
+								enabled: false,
+								srcs: [
+									"default_py3.py",
+								],
+							},
+						},
+					}
+
+					python_library_host {
 						name: "lib5",
 						pkg_path: "a/b/",
 						srcs: [
@@ -251,6 +272,7 @@ var (
 
 					python_binary_host {
 						name: "bin",
+						defaults: ["default_lib"],
 						pkg_path: "e/",
 						srcs: [
 							"bin.py",
@@ -271,10 +293,13 @@ var (
 						},
 					}`,
 				),
-				filepath.Join("dir", "file1.py"): nil,
+				filepath.Join("dir", "default.py"):     nil,
-				filepath.Join("dir", "file2.py"): nil,
+				filepath.Join("dir", "default_py2.py"): nil,
-				filepath.Join("dir", "bin.py"):   nil,
+				filepath.Join("dir", "default_py3.py"): nil,
-				filepath.Join("dir", "file4.py"): nil,
+				filepath.Join("dir", "file1.py"):       nil,
+				filepath.Join("dir", "file2.py"):       nil,
+				filepath.Join("dir", "bin.py"):         nil,
+				filepath.Join("dir", "file4.py"):       nil,
 				stubTemplateHost: []byte(`PYTHON_BINARY = '%interpreter%'
 				MAIN_FILE = '%main%'`),
 			},
@@ -283,7 +308,9 @@ var (
 					name:          "bin",
 					actualVersion: "PY3",
 					pyRunfiles: []string{
+						"runfiles/e/default.py",
 						"runfiles/e/bin.py",
+						"runfiles/e/default_py3.py",
 						"runfiles/e/file4.py",
 					},
 					depsPyRunfiles: []string{
@@ -314,6 +341,9 @@ func TestPythonModule(t *testing.T) {
 				android.ModuleFactoryAdaptor(PythonLibraryHostFactory))
 			ctx.RegisterModuleType("python_binary_host",
 				android.ModuleFactoryAdaptor(PythonBinaryHostFactory))
+			ctx.RegisterModuleType("python_defaults",
+				android.ModuleFactoryAdaptor(defaultsFactory))
+			ctx.PreArchMutators(android.RegisterDefaultsPreArchMutators)
 			ctx.Register()
 			ctx.MockFileSystem(d.mockFiles)
 			_, testErrs := ctx.ParseBlueprintsFiles(bpFile)