send invocations to emulated interfaces through dispatch helper.

fix logic for implementing emulated interfaces.
RELNOTES: None.

PiperOrigin-RevId: 187520298

1 files changed, 41 insertions, 15 deletions

diff --git a/src/tools/android/java/com/google/devtools/build/android/desugar/EmulatedInterfaceRewriter.java b/src/tools/android/java/com/google/devtools/build/android/desugar/EmulatedInterfaceRewriter.java
index d3e786d3f3..f066f2a74c 100644
--- a/src/tools/android/java/com/google/devtools/build/android/desugar/EmulatedInterfaceRewriter.java
+++ b/src/tools/android/java/com/google/devtools/build/android/desugar/EmulatedInterfaceRewriter.java
@@ -13,18 +13,21 @@
 // limitations under the License.
 package com.google.devtools.build.android.desugar;
 
-import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedHashSet;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.Opcodes;
 
 /**
  * Visitor that renames emulated interfaces and marks classes that extend emulated interfaces to
  * also implement the renamed interfaces.  {@link DefaultMethodClassFixer} makes sure the requisite
- * methods are present.  Doing this helps with dynamic dispatch on emulated interfaces.
+ * methods are present in all classes implementing the renamed interface.  Doing this helps with
+ * dynamic dispatch on emulated interfaces.
  */
 public class EmulatedInterfaceRewriter extends ClassVisitor {
 
+  private static final String[] EMPTY_ARRAY = new String[0];
+
   private final CoreLibrarySupport support;
 
   public EmulatedInterfaceRewriter(ClassVisitor dest, CoreLibrarySupport support) {
@@ -40,24 +43,47 @@ public class EmulatedInterfaceRewriter extends ClassVisitor {
       String signature,
       String superName,
       String[] interfaces) {
-    boolean isEmulated = support.isEmulatedCoreClassOrInterface(name);
-    if (interfaces != null && interfaces.length > 0 && !isEmulated) {
-      // Make classes implementing emulated interfaces also implement the renamed interfaces we
-      // create below.
-      ArrayList<String> newInterfaces = new ArrayList<>(interfaces.length + 2);
-      Collections.addAll(newInterfaces, interfaces);
-      for (String itf : interfaces) {
-        if (support.isEmulatedCoreClassOrInterface(itf)) {
-          newInterfaces.add(support.renameCoreLibrary(itf));
+    boolean emulated = support.isEmulatedCoreClassOrInterface(name);
+    {
+      // 1. see if we should implement any additional interfaces.
+      // Use LinkedHashSet to dedupe but maintain deterministic order
+      LinkedHashSet<String> newInterfaces = new LinkedHashSet<>();
+      if (interfaces != null && interfaces.length > 0) {
+        // Make classes implementing emulated interfaces also implement the renamed interfaces we
+        // create below.  This includes making the renamed interfaces extends each other as needed.
+        Collections.addAll(newInterfaces, interfaces);
+        for (String itf : interfaces) {
+          if (support.isEmulatedCoreClassOrInterface(itf)) {
+            newInterfaces.add(support.renameCoreLibrary(itf));
+          }
+        }
+      }
+      if (!emulated) {
+        // For an immediate subclass of an emulated class, also fill in any interfaces implemented
+        // by superclasses, similar to the additional default method stubbing performed in
+        // DefaultMethodClassFixer in this situation.
+        Class<?> superclass = support.getEmulatedCoreClassOrInterface(superName);
+        while (superclass != null) {
+          for (Class<?> implemented : superclass.getInterfaces()) {
+            String itf = implemented.getName().replace('.', '/');
+            if (support.isEmulatedCoreClassOrInterface(itf)) {
+              newInterfaces.add(support.renameCoreLibrary(itf));
+            }
+          }
+          superclass = superclass.getSuperclass();
         }
       }
-      if (interfaces.length != newInterfaces.size()) {
-        interfaces = newInterfaces.toArray(interfaces);
-        signature = null; // additional interfaces invalidate signature
+      // Update implemented interfaces and signature if we did anything above
+      if (interfaces == null
+          ? !newInterfaces.isEmpty()
+          : interfaces.length != newInterfaces.size()) {
+        interfaces = newInterfaces.toArray(EMPTY_ARRAY);
+        signature = null; // additional interfaces invalidate any signature
       }
     }
 
-    if (BitFlags.isInterface(access) && isEmulated) {
+    // 2. see if we need to rename this interface itself
+    if (BitFlags.isInterface(access) && emulated) {
       name = support.renameCoreLibrary(name);
     }
     super.visit(version, access, name, signature, superName, interfaces);