Merge "Add sdk_genrule" into main
diff --git a/android/arch.go b/android/arch.go
index 7436660..c39db02 100644
--- a/android/arch.go
+++ b/android/arch.go
@@ -446,8 +446,10 @@
 		}
 	}
 
+	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 @@
 		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
diff --git a/sdk/Android.bp b/sdk/Android.bp
index f42b478..f436320 100644
--- a/sdk/Android.bp
+++ b/sdk/Android.bp
@@ -18,6 +18,7 @@
         "bp.go",
         "build_release.go",
         "exports.go",
+        "genrule.go",
         "member_trait.go",
         "member_type.go",
         "sdk.go",
@@ -30,6 +31,7 @@
         "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",
diff --git a/sdk/genrule.go b/sdk/genrule.go
new file mode 100644
index 0000000..347ab05
--- /dev/null
+++ b/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
+}
diff --git a/sdk/genrule_test.go b/sdk/genrule_test.go
new file mode 100644
index 0000000..6e52a3d
--- /dev/null
+++ b/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)
+}
diff --git a/sdk/sdk.go b/sdk/sdk.go
index 4d4a2a2..fd16ab6 100644
--- a/sdk/sdk.go
+++ b/sdk/sdk.go
@@ -222,6 +222,18 @@
 	}}
 }
 
+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.