Add a way for extensions to retrieve the name of the final AutoValue_…

…Foo class.

RELNOTES=Add a way for extensions to retrieve the name of the final AutoValue_Foo class.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=273511598

value/src/main/java/com/google/auto/value/extension/AutoValueExtension.java

@@ -94,6 +94,20 @@ public interface Context {
      */
     TypeElement autoValueClass();
 
+    /**
+     * The fully-qualified name of the last class in the {@code AutoValue} hierarchy. For an
+     * {@code @AutoValue} class {@code foo.bar.Baz}, this will be {@code foo.bar.AutoValue_Baz}.
+     * The class may be generated by an extension, which will be the current extension if the
+     * {@code isFinal} parameter to {@link AutoValueExtension#generateClass} is true and the
+     * returned string is not {@code null}.
+     *
+     * <p>For compatibility reasons, this method has a default implementation that throws an
+     * exception. The AutoValue processor supplies an implementation that behaves as documented.
+     */
+    default String finalAutoValueClassName() {
+      throw new UnsupportedOperationException();
+    }
+
     /**
      * Returns the ordered collection of properties to be generated by AutoValue. Each key is a
      * property name, and the corresponding value is the getter method for that property. For

value/src/main/java/com/google/auto/value/processor/AutoValueProcessor.java

@@ -151,7 +151,7 @@ private static ImmutableSet<String> optionsFor(
     throw new AssertionError(incrementalType);
   }
 
-  private static String generatedSubclassName(TypeElement type, int depth) {
+  static String generatedSubclassName(TypeElement type, int depth) {
     return generatedClassName(type, Strings.repeat("$", depth) + "AutoValue_");
   }
 

value/src/main/java/com/google/auto/value/processor/ExtensionContext.java

@@ -31,20 +31,20 @@
 class ExtensionContext implements AutoValueExtension.Context {
 
   private final ProcessingEnvironment processingEnvironment;
-  private final TypeElement typeElement;
+  private final TypeElement autoValueClass;
   private final ImmutableMap<String, ExecutableElement> properties;
   private final ImmutableMap<String, TypeMirror> propertyTypes;
   private final ImmutableSet<ExecutableElement> abstractMethods;
   private Optional<BuilderContext> builderContext = Optional.empty();
 
   ExtensionContext(
       ProcessingEnvironment processingEnvironment,
-      TypeElement typeElement,
+      TypeElement autoValueClass,
       ImmutableMap<String, ExecutableElement> properties,
       ImmutableMap<ExecutableElement, TypeMirror> propertyMethodsAndTypes,
       ImmutableSet<ExecutableElement> abstractMethods) {
     this.processingEnvironment = processingEnvironment;
-    this.typeElement = typeElement;
+    this.autoValueClass = autoValueClass;
     this.properties = properties;
     this.propertyTypes =
         ImmutableMap.copyOf(Maps.transformValues(properties, propertyMethodsAndTypes::get));
@@ -62,12 +62,17 @@ public ProcessingEnvironment processingEnvironment() {
 
   @Override
   public String packageName() {
-    return TypeSimplifier.packageNameOf(typeElement);
+    return TypeSimplifier.packageNameOf(autoValueClass);
   }
 
   @Override
   public TypeElement autoValueClass() {
-    return typeElement;
+    return autoValueClass;
+  }
+
+  @Override
+  public String finalAutoValueClassName() {
+    return AutoValueProcessor.generatedSubclassName(autoValueClass, 0);
   }
 
   @Override

value/src/test/java/com/google/auto/value/processor/ExtensionTest.java

@@ -925,6 +925,31 @@ public void propertyTypes() {
         .compilesWithoutError();
   }
 
+  @Test
+  public void finalAutoValueClassName() {
+    JavaFileObject autoValueClass = JavaFileObjects.forSourceLines(
+        "foo.bar.Baz",
+        "package foo.bar;",
+        "",
+        "import com.google.auto.value.AutoValue;",
+        "",
+        "@AutoValue",
+        "abstract class Baz {",
+        "}");
+    ContextChecker checker =
+        context -> {
+          assertThat(context.finalAutoValueClassName()).isEqualTo("foo.bar.AutoValue_Baz");
+        };
+    ContextCheckingExtension extension = new ContextCheckingExtension(checker);
+    assertThat(autoValueClass)
+        .processedWith(new AutoValueProcessor(ImmutableList.of(extension, new FinalExtension())))
+        .compilesWithoutError()
+        .and()
+        .generatesFileNamed(StandardLocation.SOURCE_OUTPUT, "foo.bar", "AutoValue_Baz.java");
+    // ContextCheckingExtension doesn't generate any code, so that name must be the class generated
+    // by FinalExtension.
+  }
+
   @Test
   public void builderContext() {
     JavaFileObject parent = JavaFileObjects.forSourceLines(