Minimal license feature.

Keeps license declarations from breaking the build without implementing
the full feature.

Test: m all

Bug: 181768532

Change-Id: Ic78672cd25da13aa9078a48b06446f66780c792d
Merged-in: If3fbc157c6ffed8e3ee4bdd9aa56fabe2c24444b
Merged-in: Ie7e1695ecb8cd943124426a0cad2c0d1db2b46ed
diff --git a/android/Android.bp b/android/Android.bp
index 9712c46..bd72b7b 100644
--- a/android/Android.bp
+++ b/android/Android.bp
@@ -23,6 +23,7 @@
         "filegroup.go",
         "hooks.go",
         "image.go",
+        "license.go",
         "makevars.go",
         "module.go",
         "mutator.go",
@@ -62,6 +63,7 @@
         "csuite_config_test.go",
         "depset_test.go",
         "expand_test.go",
+        "license_test.go",
         "module_test.go",
         "mutator_test.go",
         "namespace_test.go",
diff --git a/android/license.go b/android/license.go
new file mode 100644
index 0000000..00ddacd
--- /dev/null
+++ b/android/license.go
@@ -0,0 +1,70 @@
+// Copyright 2020 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
+
+func init() {
+	RegisterLicenseBuildComponents(InitRegistrationContext)
+}
+
+// Register the license module type.
+func RegisterLicenseBuildComponents(ctx RegistrationContext) {
+	ctx.RegisterModuleType("license", LicenseFactory)
+}
+
+type licenseProperties struct {
+	// Specifies the kinds of license that apply.
+	License_kinds []string
+	// Specifies a short copyright notice to use for the license.
+	Copyright_notice *string
+	// Specifies the path or label for the text of the license.
+	License_text []string `android:"path"`
+	// Specifies the package name to which the license applies.
+	Package_name *string
+	// Specifies where this license can be used
+	Visibility []string
+}
+
+type licenseModule struct {
+	ModuleBase
+	DefaultableModuleBase
+
+	properties licenseProperties
+}
+
+func (m *licenseModule) DepsMutator(ctx BottomUpMutatorContext) {
+	// Do nothing.
+}
+
+func (m *licenseModule) GenerateAndroidBuildActions(ctx ModuleContext) {
+	// Nothing to do.
+}
+
+func LicenseFactory() Module {
+	module := &licenseModule{}
+
+	base := module.base()
+	module.AddProperties(&base.nameProperties, &module.properties)
+
+	base.generalProperties = module.GetProperties()
+	base.customizableProperties = module.GetProperties()
+
+	// The visibility property needs to be checked and parsed by the visibility module.
+	setPrimaryVisibilityProperty(module, "visibility", &module.properties.Visibility)
+
+	initAndroidModuleBase(module)
+	InitDefaultableModule(module)
+
+	return module
+}
diff --git a/android/license_test.go b/android/license_test.go
new file mode 100644
index 0000000..e80ba5e
--- /dev/null
+++ b/android/license_test.go
@@ -0,0 +1,142 @@
+package android
+
+import (
+	"testing"
+)
+
+var licenseTests = []struct {
+	name           string
+	fs             map[string][]byte
+	expectedErrors []string
+}{
+	{
+		name: "license must not accept licenses property",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				license {
+					name: "top_license",
+					visibility: ["//visibility:private"],
+					licenses: ["other_license"],
+
+				}`),
+		},
+		expectedErrors: []string{
+			`top/Blueprints:5:14: unrecognized property "licenses"`,
+		},
+	},
+	{
+		name: "public license",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				license {
+					name: "top_proprietary",
+					license_kinds: ["top_by_exception_only"],
+					visibility: ["//visibility:public"],
+				}`),
+			"other/Blueprints": []byte(`
+				rule {
+					name: "arule",
+					licenses: ["top_proprietary"],
+
+				}`),
+			"yetmore/Blueprints": []byte(`
+				package {
+					default_applicable_licenses: ["top_proprietary"],
+				}`),
+		},
+	},
+	{
+		name: "multiple licenses",
+		fs: map[string][]byte{
+			"top/Blueprints": []byte(`
+				package {
+					default_applicable_licenses: ["top_proprietary"],
+				}
+				license {
+					name: "top_allowed_as_notice",
+					license_kinds: ["top_notice"],
+				}
+				license {
+					name: "top_proprietary",
+					license_kinds: ["top_by_exception_only"],
+					visibility: ["//visibility:public"],
+				}
+				rule {
+					name: "myrule",
+					licenses: ["top_allowed_as_notice", "top_proprietary"]
+				}`),
+			"other/Blueprints": []byte(`
+				rule {
+					name: "arule",
+					licenses: ["top_proprietary"],
+
+				}`),
+			"yetmore/Blueprints": []byte(`
+				package {
+					default_applicable_licenses: ["top_proprietary"],
+				}`),
+		},
+	},
+}
+
+func TestLicense(t *testing.T) {
+	for _, test := range licenseTests {
+		t.Run(test.name, func(t *testing.T) {
+			_, errs := testLicense(test.fs)
+			expectedErrors := test.expectedErrors
+			if expectedErrors == nil {
+				FailIfErrored(t, errs)
+			} else {
+				for _, expectedError := range expectedErrors {
+					FailIfNoMatchingErrors(t, expectedError, errs)
+				}
+				if len(errs) > len(expectedErrors) {
+					t.Errorf("additional errors found, expected %d, found %d", len(expectedErrors), len(errs))
+					for i, expectedError := range expectedErrors {
+						t.Errorf("expectedErrors[%d] = %s", i, expectedError)
+					}
+					for i, err := range errs {
+						t.Errorf("errs[%d] = %s", i, err)
+					}
+				}
+			}
+		})
+	}
+}
+func testLicense(fs map[string][]byte) (*TestContext, []error) {
+	// Create a new config per test as visibility information is stored in the config.
+	env := make(map[string]string)
+	env["ANDROID_REQUIRE_LICENSES"] = "1"
+	config := TestArchConfig(buildDir, env, "", fs)
+	ctx := NewTestArchContext()
+	RegisterPackageBuildComponents(ctx)
+	registerTestPrebuiltBuildComponents(ctx)
+	RegisterLicenseBuildComponents(ctx)
+	ctx.RegisterModuleType("rule", newMockRuleModule)
+	ctx.PreArchMutators(RegisterVisibilityRuleChecker)
+	ctx.PreArchMutators(RegisterDefaultsPreArchMutators)
+	ctx.PreArchMutators(RegisterVisibilityRuleGatherer)
+	ctx.PostDepsMutators(RegisterVisibilityRuleEnforcer)
+	ctx.Register(config)
+	_, errs := ctx.ParseBlueprintsFiles(".")
+	if len(errs) > 0 {
+		return ctx, errs
+	}
+	_, errs = ctx.PrepareBuildActions(config)
+	return ctx, errs
+}
+
+type mockRuleModule struct {
+	ModuleBase
+	DefaultableModuleBase
+}
+
+func newMockRuleModule() Module {
+	m := &mockRuleModule{}
+	InitAndroidModule(m)
+	InitDefaultableModule(m)
+	return m
+}
+
+func (p *mockRuleModule) GenerateAndroidBuildActions(ModuleContext) {
+}
diff --git a/android/module.go b/android/module.go
index cd4baab..a498839 100644
--- a/android/module.go
+++ b/android/module.go
@@ -360,6 +360,9 @@
 	// more details.
 	Visibility []string
 
+	// Names of the licenses that apply to this module.
+	Licenses []string
+
 	// control whether this module compiles for 32-bit, 64-bit, or both.  Possible values
 	// are "32" (compile for 32-bit only), "64" (compile for 64-bit only), "both" (compile for both
 	// architectures), or "first" (compile for 64-bit on a 64-bit platform, and 32-bit on a 32-bit
diff --git a/android/package.go b/android/package.go
index 182b3ed..053fec2 100644
--- a/android/package.go
+++ b/android/package.go
@@ -31,6 +31,8 @@
 type packageProperties struct {
 	// Specifies the default visibility for all modules defined in this package.
 	Default_visibility []string
+	// Specifies the names of the default licenses for all modules defined in this package.
+	Default_applicable_licenses []string
 }
 
 type packageModule struct {
diff --git a/android/package_test.go b/android/package_test.go
index 04dfc08..f25599c 100644
--- a/android/package_test.go
+++ b/android/package_test.go
@@ -44,6 +44,7 @@
 			"top/Blueprints": []byte(`
 				package {
 					default_visibility: ["//visibility:private"],
+					default_applicable_licenses: ["license"],
 				}
 
         package {