Prevent ASM ClassWriter from swallowing important exceptions

Mumfrey
1 parent 7a0a5ccd
Showing 1 changed file with 49 additions and 1 deletions
src/main/java/com/mumfrey/liteloader/transformers/IsolatedClassWriter.java
@@ -19,9 +19,57 @@ public class IsolatedClassWriter extends ClassWriter
     {
         super(flags);
     }
-
+    
     public IsolatedClassWriter(ClassReader classReader, int flags)
     {
         super(classReader, flags);
     }
+    
+    /**
+     * Returns the common super type of the two given types. The default
+     * implementation of this method <i>loads</i> the two given classes and uses
+     * the java.lang.Class methods to find the common super class. It can be
+     * overridden to compute this common super type in other ways, in particular
+     * without actually loading any class, or to take into account the class
+     * that is currently being generated by this ClassWriter, which can of
+     * course not be loaded since it is under construction.
+     * 
+     * @param type1 the internal name of a class.
+     * @param type2 the internal name of another class.
+     * @return the internal name of the common super class of the two given
+     *         classes.
+     */
+    @Override
+    protected String getCommonSuperClass(final String type1, final String type2)
+    {
+        Class<?> c, d;
+        ClassLoader classLoader = getClass().getClassLoader();
+        try
+        {
+            c = Class.forName(type1.replace('/', '.'), false, classLoader);
+            d = Class.forName(type2.replace('/', '.'), false, classLoader);
+        }
+        catch (Exception e)
+        {
+            throw new RuntimeException(e.toString(), e);
+        }
+        
+        if (c.isAssignableFrom(d))
+        {
+            return type1;
+        }
+        if (d.isAssignableFrom(c))
+        {
+            return type2;
+        }
+        if (c.isInterface() || d.isInterface())
+        {
+            return "java/lang/Object";
+        }
+        do
+        {
+            c = c.getSuperclass();
+        } while (!c.isAssignableFrom(d));
+        return c.getName().replace('.', '/');
+    }
 }