Introduce a java_system_features_srcs wrapper for codegen

Use soong to aggregate all system feature-related build flags as input
to the existing system feature codegen tool. Use this instead of the
more clumsy raw genrule variant. This is an effective no-op in terms of
generated code or framework impact, but should improve maintainability.

Test: m --no-skip-soong-tests
Bug: 203143243
Change-Id: I67158dd6f0454556f8d75685cfc86a68b3e47089

4 files changed, 173 insertions, 0 deletions

diff --git a/systemfeatures/Android.bp b/systemfeatures/Android.bp
new file mode 100644
index 000000000..a65a6b644
--- /dev/null
+++ b/systemfeatures/Android.bp
@@ -0,0 +1,18 @@
+package {
+    default_applicable_licenses: ["Android-Apache-2.0"],
+}
+
+bootstrap_go_package {
+    name: "soong-systemfeatures",
+    pkgPath: "android/soong/systemfeatures",
+    deps: [
+        "blueprint",
+        "blueprint-proptools",
+        "soong",
+        "soong-android",
+        "soong-java",
+    ],
+    srcs: ["system_features.go"],
+    testSrcs: ["system_features_test.go"],
+    pluginFor: ["soong_build"],
+}
diff --git a/systemfeatures/OWNERS b/systemfeatures/OWNERS
new file mode 100644
index 000000000..3e4480647
--- /dev/null
+++ b/systemfeatures/OWNERS
@@ -0,0 +1,2 @@
+jdduke@google.com
+shayba@google.com
diff --git a/systemfeatures/system_features.go b/systemfeatures/system_features.go
new file mode 100644
index 000000000..0c1a56676
--- /dev/null
+++ b/systemfeatures/system_features.go
@@ -0,0 +1,102 @@
+// Copyright 2024 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 systemfeatures
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+
+	"android/soong/android"
+	"android/soong/genrule"
+)
+
+var (
+	pctx = android.NewPackageContext("android/soong/systemfeatures")
+)
+
+func init() {
+	registerSystemFeaturesComponents(android.InitRegistrationContext)
+}
+
+func registerSystemFeaturesComponents(ctx android.RegistrationContext) {
+	ctx.RegisterModuleType("java_system_features_srcs", JavaSystemFeaturesSrcsFactory)
+}
+
+type javaSystemFeaturesSrcs struct {
+	android.ModuleBase
+	properties struct {
+		// The fully qualified class name for the generated code, e.g., com.android.Foo
+		Full_class_name string
+	}
+	outputFiles android.WritablePaths
+}
+
+var _ genrule.SourceFileGenerator = (*javaSystemFeaturesSrcs)(nil)
+var _ android.SourceFileProducer = (*javaSystemFeaturesSrcs)(nil)
+
+func (m *javaSystemFeaturesSrcs) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	// Create a file name appropriate for the given fully qualified (w/ package) class name.
+	classNameParts := strings.Split(m.properties.Full_class_name, ".")
+	outputDir := android.PathForModuleGen(ctx)
+	outputFileName := classNameParts[len(classNameParts)-1] + ".java"
+	outputFile := android.PathForModuleGen(ctx, outputFileName).OutputPath
+
+	// Collect all RELEASE_SYSTEM_FEATURE_$K:$V build flags into a list of "$K:$V" pairs.
+	var features []string
+	for k, v := range ctx.Config().ProductVariables().BuildFlags {
+		if strings.HasPrefix(k, "RELEASE_SYSTEM_FEATURE_") {
+			shortFeatureName := strings.TrimPrefix(k, "RELEASE_SYSTEM_FEATURE_")
+			features = append(features, fmt.Sprintf("%s:%s", shortFeatureName, v))
+		}
+	}
+	// Ensure sorted outputs for consistency of flag ordering in ninja outputs.
+	sort.Strings(features)
+
+	rule := android.NewRuleBuilder(pctx, ctx)
+	rule.Command().Text("rm -rf").Text(outputDir.String())
+	rule.Command().Text("mkdir -p").Text(outputDir.String())
+	rule.Command().
+		BuiltTool("systemfeatures-gen-tool").
+		Flag(m.properties.Full_class_name).
+		FlagForEachArg("--feature=", features).
+		FlagWithArg("--readonly=", fmt.Sprint(ctx.Config().ReleaseUseSystemFeatureBuildFlags())).
+		FlagWithOutput(" > ", outputFile)
+	rule.Build(ctx.ModuleName(), "Generating systemfeatures srcs filegroup")
+
+	m.outputFiles = append(m.outputFiles, outputFile)
+}
+
+func (m *javaSystemFeaturesSrcs) Srcs() android.Paths {
+	return m.outputFiles.Paths()
+}
+
+func (m *javaSystemFeaturesSrcs) GeneratedSourceFiles() android.Paths {
+	return m.outputFiles.Paths()
+}
+
+func (m *javaSystemFeaturesSrcs) GeneratedDeps() android.Paths {
+	return m.outputFiles.Paths()
+}
+
+func (m *javaSystemFeaturesSrcs) GeneratedHeaderDirs() android.Paths {
+	return nil
+}
+
+func JavaSystemFeaturesSrcsFactory() android.Module {
+	module := &javaSystemFeaturesSrcs{}
+	module.AddProperties(&module.properties)
+	android.InitAndroidModule(module)
+	return module
+}
diff --git a/systemfeatures/system_features_test.go b/systemfeatures/system_features_test.go
new file mode 100644
index 000000000..558bb958e
--- /dev/null
+++ b/systemfeatures/system_features_test.go
@@ -0,0 +1,51 @@
+// Copyright 2024 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 systemfeatures
+
+import (
+	"android/soong/android"
+
+	"testing"
+)
+
+func TestJavaSystemFeaturesSrcs(t *testing.T) {
+	bp := `
+java_system_features_srcs {
+    name: "system-features-srcs",
+	full_class_name: "com.android.test.RoSystemFeatures",
+}
+`
+
+	res := android.GroupFixturePreparers(
+		android.FixtureRegisterWithContext(registerSystemFeaturesComponents),
+		android.PrepareForTestWithBuildFlag("RELEASE_USE_SYSTEM_FEATURE_BUILD_FLAGS", "true"),
+		android.PrepareForTestWithBuildFlag("RELEASE_SYSTEM_FEATURE_AUTOMOTIVE", "0"),
+		android.PrepareForTestWithBuildFlag("RELEASE_SYSTEM_FEATURE_TELEVISION", "UNAVAILABLE"),
+		android.PrepareForTestWithBuildFlag("RELEASE_SYSTEM_FEATURE_WATCH", ""),
+		android.PrepareForTestWithBuildFlag("RELEASE_NOT_SYSTEM_FEATURE_FOO", "BAR"),
+	).RunTestWithBp(t, bp)
+
+	module := res.ModuleForTests("system-features-srcs", "")
+	cmd := module.Rule("system-features-srcs").RuleParams.Command
+	android.AssertStringDoesContain(t, "Expected fully class name", cmd, " com.android.test.RoSystemFeatures ")
+	android.AssertStringDoesContain(t, "Expected readonly flag", cmd, "--readonly=true")
+	android.AssertStringDoesContain(t, "Expected AUTOMOTIVE feature flag", cmd, "--feature=AUTOMOTIVE:0 ")
+	android.AssertStringDoesContain(t, "Expected TELEVISION feature flag", cmd, "--feature=TELEVISION:UNAVAILABLE ")
+	android.AssertStringDoesContain(t, "Expected WATCH feature flag", cmd, "--feature=WATCH: ")
+	android.AssertStringDoesNotContain(t, "Unexpected FOO arg from non-system feature flag", cmd, "FOO")
+
+	systemFeaturesModule := module.Module().(*javaSystemFeaturesSrcs)
+	expectedOutputPath := "out/soong/.intermediates/system-features-srcs/gen/RoSystemFeatures.java"
+	android.AssertPathsRelativeToTopEquals(t, "Expected output file", []string{expectedOutputPath}, systemFeaturesModule.Srcs())
+}