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Commit 807df5e7 authored by Jared Duke's avatar Jared Duke
Browse files

Support system feature lookups in host tooling 

Introduce a host utility that does the following:
  * Scrapes public Metalava API files for PackageManager.FEATURE_ defs
  * Generates a simple utility class that maps from feature var values
    to their respective feature names, e.g.,
      * "android.software.print" -> "FEATURE_PRINTING"

This lookup will enable host parsing of <feature /> and
<unavailable-feature /> permission defs and integration in existing
system feature codegen, *without* needing a strict dependency on the
framework. This breaks any cyclic deps, allowing us to scrape product
permission .xml files and feed that back into build-time system feature
codegen for the framework.

Note: This change only adds the host utility, it doesn't make changes
to existing codegen. A follow-up change will do so, behind a build flag.

Bug: 203143243
Test: atest systemfeatures-gen-tests
Flag: EXEMPT simple tool addition
Change-Id: I210674c85efb068ac0e2d1898df590aab330db2b
parent e835c3b4

core/api/Android.bp

+2 −0
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ package { 
    default_visibility: [

        "//frameworks/base",

        "//frameworks/base/api",

        "//frameworks/base/tools/systemfeatures",

    ],

    // See: http://go/android-license-faq

    // A large-scale-change added 'default_applicable_licenses' to import
@@ -63,6 +64,7 @@ filegroup { 
    visibility: [

        "//frameworks/base",

        "//frameworks/base/api",

        "//frameworks/base/tools/systemfeatures",

        "//cts/tests/signature/api",

    ],

}

tools/systemfeatures/Android.bp

+51 −3
Original line number Diff line number Diff line
@@ -8,12 +8,13 @@ package { 
    default_team: "trendy_team_system_performance",

}



// Code generation for compile-time system feature queries in the framework.

java_library_host {

    name: "systemfeatures-gen-lib",

    srcs: [

        "src/**/*.java",

        "src/**/*.kt",

        ":framework-metalava-annotations",

        ":systemfeatures-lookup-srcs",

        "src/com/android/systemfeatures/SystemFeaturesGenerator.kt",

    ],

    static_libs: [

        "guava",
@@ -27,10 +28,56 @@ java_binary_host { 
    static_libs: ["systemfeatures-gen-lib"],

}



// Code generation for system feature name lookups in host tools that cannot

// depend on the framework.

java_library_host {

    name: "systemfeatures-lookup-gen-lib",

    srcs: ["src/com/android/systemfeatures/SystemFeaturesLookupGenerator.kt"],

    static_libs: [

        "javapoet",

        "metalava-signature-reader",

    ],

    visibility: ["//visibility:private"],

}



java_binary_host {

    name: "systemfeatures-lookup-gen-tool",

    main_class: "com.android.systemfeatures.SystemFeaturesLookupGenerator",

    static_libs: ["systemfeatures-lookup-gen-lib"],

    visibility: ["//visibility:private"],

}



genrule {

    name: "systemfeatures-lookup-srcs",

    cmd: "$(location systemfeatures-lookup-gen-tool) $(in) > $(out)",

    out: ["SystemFeaturesLookup.java"],

    srcs: [

        ":non-updatable-current.txt",

        ":non-updatable-module-lib-current.txt",

        ":non-updatable-system-current.txt",

        ":non-updatable-test-current.txt",

    ],

    tools: ["systemfeatures-lookup-gen-tool"],

    visibility: ["//visibility:private"],

}



// Code generation for runtime system feature metadata queries in the framework.

java_library_host {

    name: "systemfeatures-metadata-lib",

    srcs: [

        ":framework-metalava-annotations",

        "src/com/android/systemfeatures/SystemFeaturesMetadataProcessor.kt",

    ],

    static_libs: [

        "guava",

        "javapoet",

    ],

}



java_plugin {

    name: "systemfeatures-metadata-processor",

    processor_class: "com.android.systemfeatures.SystemFeaturesMetadataProcessor",

    static_libs: ["systemfeatures-gen-lib"],

    static_libs: ["systemfeatures-metadata-lib"],

}



genrule {
@@ -66,6 +113,7 @@ java_test_host { 
        "objenesis",

        "mockito",

        "systemfeatures-gen-lib",

        "systemfeatures-lookup-gen-lib",

        "truth",

    ],

    plugins: ["systemfeatures-metadata-processor"],

tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesGenerator.kt

+6 −5
Original line number Diff line number Diff line
@@ -213,11 +213,12 @@ object SystemFeaturesGenerator { 


    private fun parseFeatureName(name: String): String =

        when {

            name.startsWith("android") ->

                throw IllegalArgumentException(

                    "Invalid feature name input: \"android\"-namespaced features must be " +

                    "provided as PackageManager.FEATURE_* suffixes, not raw feature strings."

            name.startsWith("android") -> {

                SystemFeaturesLookup.getDeclaredFeatureVarNameFromValue(name)

                    ?: throw IllegalArgumentException(

                        "Unrecognized Android system feature name: $name"

                    )

            }

            name.startsWith("FEATURE_") -> name

            else -> "FEATURE_$name"

        }

tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesLookupGenerator.kt

0 → 100644
+116 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2025 The Android Open Source Project

 *

 * 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 com.android.systemfeatures



import com.android.tools.metalava.model.text.ApiFile

import com.squareup.javapoet.ClassName

import com.squareup.javapoet.JavaFile

import com.squareup.javapoet.MethodSpec

import com.squareup.javapoet.TypeSpec

import java.io.File

import javax.lang.model.element.Modifier



/*

 * Simple Java code generator that takes as input a list of Metalava API files and generates an

 * accessory class that maps from PackageManager system feature variable values to their

 * declared PackageManager variable names. This is needed for host tooling that cannot depend

 * directly on the base framework lib/srcs.

 *

 * <pre>

 * package com.android.systemfeatures;

 * public final class SystemFeaturesLookup {

 *     // Gets the declared system feature var name from its string value.

 *     // Example: "android.software.print" -> "FEATURE_PRINTING"

 *     public static String getDeclaredFeatureVarNameFromValue(String featureVarValue);

 * }

 * </pre>

 */

object SystemFeaturesLookupGenerator {



    /** Main entrypoint for system feature constant lookup codegen. */

    @JvmStatic

    fun main(args: Array<String>) {

        generate(args.asIterable(), System.out)

    }



    /**

     * Simple API entrypoint for system feature lookup codegen.

     *

     * Given a list of Metalava API files, pipes a generated SystemFeaturesLookup class into output.

     */

    @JvmStatic

    fun generate(apiFilePaths: Iterable<String>, output: Appendable) {

        val featuresMap = parse(apiFilePaths)



        val stringClassName = ClassName.get(String::class.java)



        val featureLookupMethod =

            MethodSpec.methodBuilder("getDeclaredFeatureVarNameFromValue")

                .addModifiers(Modifier.PUBLIC, Modifier.STATIC)

                .addAnnotation(ClassName.get("android.annotation", "Nullable"))

                .addJavadoc("Gets the declared system feature var name from its string value.")

                .addJavadoc("\n\nExample: \"android.software.print\" -> \"FEATURE_PRINTING\"")

                .addJavadoc("\n\n@hide")

                .returns(stringClassName)

                .addParameter(stringClassName, "featureVarValue")

                .beginControlFlow("switch (featureVarValue)")

                .apply {

                    featuresMap.forEach { (key, value) ->

                        addStatement("case \$S: return \$S", key, value)

                    }

                }

                .addStatement("default: return null")

                .endControlFlow()

                .build()



        val outputClassName = ClassName.get("com.android.systemfeatures", "SystemFeaturesLookup")

        val systemFeaturesApiLookupClass =

            TypeSpec.classBuilder(outputClassName)

                .addModifiers(Modifier.PUBLIC, Modifier.FINAL)

                .addMethod(featureLookupMethod)

                .addJavadoc("@hide")

                .build()



        JavaFile.builder(outputClassName.packageName(), systemFeaturesApiLookupClass)

            .indent("    ")

            .skipJavaLangImports(true)

            .addFileComment("This file is auto-generated. DO NOT MODIFY.\n")

            .build()

            .writeTo(output)

    }



    /**

     * Given a list of Metalava API files, extracts a mapping from all @SdkConstantType.FEATURE

     * PackageManager values to their declared variable names, e.g.,

     * - "android.hardware.type.automotive" -> "FEATURE_AUTOMOTIVE"

     * - "android.software.print" -> "FEATURE_PRINTING"

     */

    @JvmStatic

    fun parse(apiFilePaths: Iterable<String>): Map<String, String> {

        return ApiFile.parseApi(apiFilePaths.map(::File))

            .findClass("android.content.pm.PackageManager")

            ?.fields()

            ?.filter { field ->

                field.type().isString() &&

                    field.modifiers.isStatic() &&

                    field.modifiers.isFinal() &&

                    field.name().startsWith("FEATURE_") &&

                    field.legacyInitialValue() != null

            }

            ?.associateBy({ it.legacyInitialValue()!!.toString() }, { it.name() }) ?: emptyMap()

    }

}

tools/systemfeatures/tests/src/SystemFeaturesGeneratorApiTest.java

+10 −0
Original line number Diff line number Diff line
@@ -78,4 +78,14 @@ public class SystemFeaturesGeneratorApiTest { 
        SystemFeaturesGenerator.generate(args, mOut);

        verify(mOut, never()).append(any());

    }



    @Test

    public void testValidFeatureNameFromAndroidNamespace() throws IOException {

        final String[] args = new String[] {

            "com.foo.Features",

            "--feature=android.hardware.touchscreen:0",

        };

        SystemFeaturesGenerator.generate(args, mOut);

        verify(mOut, atLeastOnce()).append(any());

    }

}