Add SystemFeaturesMetadata.maybeGetSdkFeatureIndex
Add a simple index lookup method for feature names. This returns:
* [0, SDK_FEATURE_INDEX) for PackageManager-defined system features
* -1 otherwise
This will be used in a follow-up to efficiently compute a dense array
of cached system feature versions that can be used for fast lookup in
client processes.
Bug: 375000483
Test: atest SystemFeaturesMetadataProcessorTest
Flag: EXEMPT currently unused
Change-Id: I145c08f7eb58b832534f62950357a18f7b4e3651
diff --git a/tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesMetadataProcessor.kt b/tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesMetadataProcessor.kt
index 100d869..4a6d4b1 100644
--- a/tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesMetadataProcessor.kt
+++ b/tools/systemfeatures/src/com/android/systemfeatures/SystemFeaturesMetadataProcessor.kt
@@ -17,8 +17,10 @@
package com.android.systemfeatures
import android.annotation.SdkConstant
+import com.squareup.javapoet.ClassName
import com.squareup.javapoet.FieldSpec
import com.squareup.javapoet.JavaFile
+import com.squareup.javapoet.MethodSpec
import com.squareup.javapoet.TypeSpec
import java.io.IOException
import javax.annotation.processing.AbstractProcessor
@@ -27,6 +29,7 @@
import javax.lang.model.SourceVersion
import javax.lang.model.element.Modifier
import javax.lang.model.element.TypeElement
+import javax.lang.model.element.VariableElement
import javax.tools.Diagnostic
/*
@@ -35,7 +38,16 @@
* <p>The output is a single class file, `com.android.internal.pm.SystemFeaturesMetadata`, with
* properties computed from feature constant definitions in the PackageManager class. This
* class is only produced if the processed environment includes PackageManager; all other
- * invocations are ignored.
+ * invocations are ignored. The generated API is as follows:
+ *
+ * <pre>
+ * package android.content.pm;
+ * public final class SystemFeaturesMetadata {
+ * public static final int SDK_FEATURE_COUNT;
+ * // @return [0, SDK_FEATURE_COUNT) if an SDK-defined system feature, -1 otherwise.
+ * public static int maybeGetSdkFeatureIndex(String featureName);
+ * }
+ * </pre>
*/
class SystemFeaturesMetadataProcessor : AbstractProcessor() {
@@ -56,19 +68,31 @@
return false
}
- // We're only interested in feature constants defined in PackageManager.
- var featureCount = 0
- roundEnv.getElementsAnnotatedWith(SdkConstant::class.java).forEach {
- if (
- it.enclosingElement == packageManagerType &&
- it.getAnnotation(SdkConstant::class.java).value ==
- SdkConstant.SdkConstantType.FEATURE
- ) {
- featureCount++
- }
- }
+ // Collect all FEATURE-annotated fields from PackageManager, and
+ // 1) Use the field values to de-duplicate, as there can be multiple FEATURE_* fields that
+ // map to the same feature string name value.
+ // 2) Ensure they're sorted to ensure consistency and determinism between builds.
+ val featureVarNames =
+ roundEnv
+ .getElementsAnnotatedWith(SdkConstant::class.java)
+ .asSequence()
+ .filter {
+ it.enclosingElement == packageManagerType &&
+ it.getAnnotation(SdkConstant::class.java).value ==
+ SdkConstant.SdkConstantType.FEATURE
+ }
+ .mapNotNull { element ->
+ (element as? VariableElement)?.let { varElement ->
+ varElement.getConstantValue()?.toString() to
+ varElement.simpleName.toString()
+ }
+ }
+ .toMap()
+ .values
+ .sorted()
+ .toList()
- if (featureCount == 0) {
+ if (featureVarNames.isEmpty()) {
// This is fine, and happens for any environment that doesn't include PackageManager.
return false
}
@@ -77,16 +101,8 @@
TypeSpec.classBuilder("SystemFeaturesMetadata")
.addModifiers(Modifier.PUBLIC, Modifier.FINAL)
.addJavadoc("@hide")
- .addField(
- FieldSpec.builder(Int::class.java, "SDK_FEATURE_COUNT")
- .addModifiers(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)
- .addJavadoc(
- "The number of `@SdkConstant` features defined in PackageManager."
- )
- .addJavadoc("@hide")
- .initializer("\$L", featureCount)
- .build()
- )
+ .addField(buildFeatureCount(featureVarNames))
+ .addMethod(buildFeatureIndexLookup(featureVarNames))
.build()
try {
@@ -104,7 +120,41 @@
return true
}
+ private fun buildFeatureCount(featureVarNames: Collection<String>): FieldSpec {
+ return FieldSpec.builder(Int::class.java, "SDK_FEATURE_COUNT")
+ .addModifiers(Modifier.PUBLIC, Modifier.STATIC, Modifier.FINAL)
+ .addJavadoc(
+ "# of {@link android.annotation.SdkConstant}` features defined in PackageManager."
+ )
+ .addJavadoc("\n\n@hide")
+ .initializer("\$L", featureVarNames.size)
+ .build()
+ }
+
+ private fun buildFeatureIndexLookup(featureVarNames: Collection<String>): MethodSpec {
+ val methodBuilder =
+ MethodSpec.methodBuilder("maybeGetSdkFeatureIndex")
+ .addModifiers(Modifier.PUBLIC, Modifier.STATIC)
+ .addJavadoc("@return an index in [0, SDK_FEATURE_COUNT) for features defined ")
+ .addJavadoc("in PackageManager, else -1.")
+ .addJavadoc("\n\n@hide")
+ .returns(Int::class.java)
+ .addParameter(String::class.java, "featureName")
+ methodBuilder.beginControlFlow("switch (featureName)")
+ featureVarNames.forEachIndexed { index, featureVarName ->
+ methodBuilder
+ .addCode("case \$T.\$N: ", PACKAGEMANAGER_CLASS, featureVarName)
+ .addStatement("return \$L", index)
+ }
+ methodBuilder
+ .addCode("default: ")
+ .addStatement("return -1")
+ .endControlFlow()
+ return methodBuilder.build()
+ }
+
companion object {
private val SDK_CONSTANT_ANNOTATION_NAME = SdkConstant::class.qualifiedName
+ private val PACKAGEMANAGER_CLASS = ClassName.get("android.content.pm", "PackageManager")
}
}
diff --git a/tools/systemfeatures/tests/src/SystemFeaturesMetadataProcessorTest.java b/tools/systemfeatures/tests/src/SystemFeaturesMetadataProcessorTest.java
index 4ffb5b9..74ce6da 100644
--- a/tools/systemfeatures/tests/src/SystemFeaturesMetadataProcessorTest.java
+++ b/tools/systemfeatures/tests/src/SystemFeaturesMetadataProcessorTest.java
@@ -16,10 +16,16 @@
package com.android.systemfeatures;
+import static com.android.internal.pm.SystemFeaturesMetadata.maybeGetSdkFeatureIndex;
+
import static com.google.common.truth.Truth.assertThat;
+import android.content.pm.PackageManager;
+
import com.android.internal.pm.SystemFeaturesMetadata;
+import com.google.common.collect.Range;
+
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.JUnit4;
@@ -33,4 +39,17 @@
// It defines 5 annotated features, and any/all other constants should be ignored.
assertThat(SystemFeaturesMetadata.SDK_FEATURE_COUNT).isEqualTo(5);
}
+
+ @Test
+ public void testSdkFeatureIndex() {
+ // Only SDK-defined features return valid indices.
+ final Range validIndexRange = Range.closedOpen(0, SystemFeaturesMetadata.SDK_FEATURE_COUNT);
+ assertThat(maybeGetSdkFeatureIndex(PackageManager.FEATURE_PC)).isIn(validIndexRange);
+ assertThat(maybeGetSdkFeatureIndex(PackageManager.FEATURE_VULKAN)).isIn(validIndexRange);
+ assertThat(maybeGetSdkFeatureIndex(PackageManager.FEATURE_NOT_ANNOTATED)).isEqualTo(-1);
+ assertThat(maybeGetSdkFeatureIndex(PackageManager.NOT_FEATURE)).isEqualTo(-1);
+ assertThat(maybeGetSdkFeatureIndex("foo")).isEqualTo(-1);
+ assertThat(maybeGetSdkFeatureIndex("0")).isEqualTo(-1);
+ assertThat(maybeGetSdkFeatureIndex("")).isEqualTo(-1);
+ }
}