Fix delegation of methods within inner static classes

Currently, delegation of inner static classes methods is broken since
the rewritten method tries to pass an instance to the outer class. This
updates the method generation to only pass the reference if the inner
class is not static.

Change-Id: I8493929cafdbd80968989b422af0f956fa65681a

2 files changed, 27 insertions, 5 deletions

diff --git a/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateClassAdapter.java b/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateClassAdapter.java
index ae4a57d..7ef7566 100644
--- a/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateClassAdapter.java
+++ b/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateClassAdapter.java
@@ -17,6 +17,7 @@
 package com.android.tools.layoutlib.create;
 
 import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.FieldVisitor;
 import org.objectweb.asm.MethodVisitor;
 import org.objectweb.asm.Opcodes;
 
@@ -40,6 +41,7 @@ public class DelegateClassAdapter extends ClassVisitor {
     private final String mClassName;
     private final Set<String> mDelegateMethods;
     private final Log mLog;
+    private boolean mIsStaticInnerClass;
 
     /**
      * Creates a new {@link DelegateClassAdapter} that can transform some methods
@@ -62,16 +64,30 @@ public class DelegateClassAdapter extends ClassVisitor {
         mLog = log;
         mClassName = className;
         mDelegateMethods = delegateMethods;
+        // If this is an inner class, by default, we assume it's static. If it's not we will detect
+        // by looking at the fields (see visitField)
+        mIsStaticInnerClass = className.contains("$");
     }
 
     //----------------------------------
     // Methods from the ClassAdapter
 
     @Override
+    public FieldVisitor visitField(int access, String name, String desc, String signature,
+            Object value) {
+        if (mIsStaticInnerClass && "this$0".equals(name)) {
+            // Having a "this$0" field, proves that this class is not a static inner class.
+            mIsStaticInnerClass = false;
+        }
+
+        return super.visitField(access, name, desc, signature, value);
+    }
+
+    @Override
     public MethodVisitor visitMethod(int access, String name, String desc,
             String signature, String[] exceptions) {
 
-        boolean isStatic = (access & Opcodes.ACC_STATIC) != 0;
+        boolean isStaticMethod = (access & Opcodes.ACC_STATIC) != 0;
         boolean isNative = (access & Opcodes.ACC_NATIVE) != 0;
 
         boolean useDelegate = (isNative && mDelegateMethods.contains(ALL_NATIVES)) ||
@@ -96,7 +112,8 @@ public class DelegateClassAdapter extends ClassVisitor {
             MethodVisitor mwDelegate = super.visitMethod(access, name, desc, signature, exceptions);
 
             DelegateMethodAdapter a = new DelegateMethodAdapter(
-                    mLog, null, mwDelegate, mClassName, name, desc, isStatic);
+                    mLog, null, mwDelegate, mClassName, name, desc, isStaticMethod,
+                    mIsStaticInnerClass);
 
             // A native has no code to visit, so we need to generate it directly.
             a.generateDelegateCode();
@@ -120,6 +137,7 @@ public class DelegateClassAdapter extends ClassVisitor {
                                                      desc, signature, exceptions);
 
         return new DelegateMethodAdapter(
-                mLog, mwOriginal, mwDelegate, mClassName, name, desc, isStatic);
+                mLog, mwOriginal, mwDelegate, mClassName, name, desc, isStaticMethod,
+                mIsStaticInnerClass);
     }
 }
diff --git a/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateMethodAdapter.java b/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateMethodAdapter.java
index 12690db..cca9e57 100644
--- a/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateMethodAdapter.java
+++ b/tools/layoutlib/create/src/com/android/tools/layoutlib/create/DelegateMethodAdapter.java
@@ -85,6 +85,8 @@ class DelegateMethodAdapter extends MethodVisitor {
     private String mDesc;
     /** True if the original method is static. */
     private final boolean mIsStatic;
+    /** True if the method is contained in a static inner class */
+    private final boolean mIsStaticInnerClass;
     /** The internal class name (e.g. <code>com/android/SomeClass$InnerClass</code>.) */
     private final String mClassName;
     /** The method name. */
@@ -120,7 +122,8 @@ class DelegateMethodAdapter extends MethodVisitor {
             String className,
             String methodName,
             String desc,
-            boolean isStatic) {
+            boolean isStatic,
+            boolean isStaticClass) {
         super(Opcodes.ASM4);
         mLog = log;
         mOrgWriter = mvOriginal;
@@ -129,6 +132,7 @@ class DelegateMethodAdapter extends MethodVisitor {
         mMethodName = methodName;
         mDesc = desc;
         mIsStatic = isStatic;
+        mIsStaticInnerClass = isStaticClass;
     }
 
     /**
@@ -206,7 +210,7 @@ class DelegateMethodAdapter extends MethodVisitor {
         // by the 'this' of any outer class, if any.
         if (!mIsStatic) {
 
-            if (outerType != null) {
+            if (outerType != null && !mIsStaticInnerClass) {
                 // The first-level inner class has a package-protected member called 'this$0'
                 // that points to the outer class.