Add sdk_genrule

Some users want to repackage the results of an sdk module.
Genrules have 3 variants: linux, android, and common_os. The common_os
one produces a snapshot zip file that users want. In order to get
access to it, we need a genrule in the same variant, so create
an sdk_genrule for that.

The sdk_genrule shouldn't have linux/android variants either, because
those other variants would get errors when trying to depend on the
sdk modules because the snapshot zip doesn't exist in those other
variants. The code in arch.go needs to be tweaked to allow a common_os
variant without the other variants.

Bug: 315962165
Test: m dist out/dist/art_release.zip
Change-Id: Idc9b3cae7a525d71aed6bafa0f8724a89f75a94b

android/arch.go

@@ -446,8 +446,10 @@ func osMutator(bpctx blueprint.BottomUpMutatorContext) {
 		}
 	}
 
+	createCommonOSVariant := base.commonProperties.CreateCommonOSVariant
+
 	// If there are no supported OSes then disable the module.
-	if len(moduleOSList) == 0 {
+	if len(moduleOSList) == 0 && !createCommonOSVariant {
 		base.Disable()
 		return
 	}
@@ -458,7 +460,6 @@ func osMutator(bpctx blueprint.BottomUpMutatorContext) {
 		osNames[i] = os.String()
 	}
 
-	createCommonOSVariant := base.commonProperties.CreateCommonOSVariant
 	if createCommonOSVariant {
 		// A CommonOS variant was requested so add it to the list of OS variants to
 		// create. It needs to be added to the end because it needs to depend on the

sdk/Android.bp

@@ -18,6 +18,7 @@ bootstrap_go_package {
         "bp.go",
         "build_release.go",
         "exports.go",
+        "genrule.go",
         "member_trait.go",
         "member_type.go",
         "sdk.go",
@@ -30,6 +31,7 @@ bootstrap_go_package {
         "cc_sdk_test.go",
         "compat_config_sdk_test.go",
         "exports_test.go",
+        "genrule_test.go",
         "java_sdk_test.go",
         "license_sdk_test.go",
         "member_trait_test.go",

sdk/genrule.go

@@ -0,0 +1,44 @@
+// Copyright 2023 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 sdk
+
+import (
+	"android/soong/android"
+	"android/soong/genrule"
+)
+
+func init() {
+	registerGenRuleBuildComponents(android.InitRegistrationContext)
+}
+
+func registerGenRuleBuildComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("sdk_genrule", SdkGenruleFactory)
+}
+
+// sdk_genrule_host is a genrule that can depend on sdk and sdk_snapshot module types
+//
+// What this means is that it's a genrule with only the "common_os" variant.
+// sdk modules have 3 variants: host, android, and common_os. The common_os one depends
+// on the host/device ones and packages their result into a final snapshot zip.
+// Genrules probably want access to this snapshot zip when they depend on an sdk module,
+// which means they want to depend on the common_os variant and not the host/android
+// variants.
+func SdkGenruleFactory() android.Module {
+	module := genrule.NewGenRule()
+
+	android.InitCommonOSAndroidMultiTargetsArchModule(module, android.NeitherHostNorDeviceSupported, android.MultilibCommon)
+	android.InitDefaultableModule(module)
+
+	return module
+}

sdk/genrule_test.go

@@ -0,0 +1,52 @@
+// Copyright 2018 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 sdk
+
+import (
+	"testing"
+
+	"android/soong/android"
+	"android/soong/genrule"
+	"android/soong/java"
+)
+
+func TestSdkGenrule(t *testing.T) {
+	// Test that an sdk_genrule can depend on an sdk, and that a genrule can depend on an sdk_genrule
+	bp := `
+				sdk {
+					name: "my_sdk",
+				}
+				sdk_genrule {
+					name: "my_sdk_genrule",
+					tool_files: ["tool"],
+					cmd: "$(location tool) $(in) $(out)",
+					srcs: [":my_sdk"],
+					out: ["out"],
+				}
+				genrule {
+					name: "my_regular_genrule",
+					srcs: [":my_sdk_genrule"],
+					out: ["out"],
+					cmd: "cp $(in) $(out)",
+				}
+			`
+	android.GroupFixturePreparers(
+		// if java components aren't registered, the sdk module doesn't create a snapshot for some reason.
+		java.PrepareForTestWithJavaBuildComponents,
+		genrule.PrepareForTestWithGenRuleBuildComponents,
+		PrepareForTestWithSdkBuildComponents,
+		android.FixtureRegisterWithContext(registerGenRuleBuildComponents),
+	).RunTestWithBp(t, bp)
+}

sdk/sdk.go

@@ -222,6 +222,18 @@ func (s *sdk) AndroidMkEntries() []android.AndroidMkEntries {
 	}}
 }
 
+func (s *sdk) OutputFiles(tag string) (android.Paths, error) {
+	switch tag {
+	case "":
+		if s.snapshotFile.Valid() {
+			return []android.Path{s.snapshotFile.Path()}, nil
+		}
+		return nil, fmt.Errorf("snapshot file not defined. This is most likely because this isn't the common_os variant of this module")
+	default:
+		return nil, fmt.Errorf("unknown tag %q", tag)
+	}
+}
+
 // gatherTraits gathers the traits from the dynamically generated trait specific properties.
 //
 // Returns a map from member name to the set of required traits.