Merge pull request #230 from fnuecke/master

Alternative setter logic for @SidedProxy in Scala classes/mods.

fml/common/cpw/mods/fml/common/ILanguageAdapter.java

@@ -1,11 +1,18 @@
 package cpw.mods.fml.common;
 
 import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.logging.Level;
+
+import cpw.mods.fml.common.Mod.Instance;
+import cpw.mods.fml.relauncher.Side;
 
 public interface ILanguageAdapter {
     public Object getNewInstance(FMLModContainer container, Class<?> objectClass, ClassLoader classLoader) throws Exception;
     public boolean supportsStatics();
     public void setProxy(Field target, Class<?> proxyTarget, Object proxy) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException;
+    public void setInternalProxies(ModContainer mod, Side side, ClassLoader loader);
 
     public static class ScalaAdapter implements ILanguageAdapter {
         @Override
@@ -24,11 +31,136 @@ public interface ILanguageAdapter {
         @Override
         public void setProxy(Field target, Class<?> proxyTarget, Object proxy) throws IllegalArgumentException, IllegalAccessException, NoSuchFieldException, SecurityException
         {
-            Field field = proxyTarget.getField("INSTANCE");
-            Object scalaObject = field.get(null);
-            target.set(scalaObject, proxy);
+            try
+            {
+                // Get the actual singleton class. The two variants are from
+                // whether the @SidedProxy is declared in a the class block
+                // of the object directly, or in the object block, i.e.
+                // whether it's:
+                // class ModName {
+                //   @SidedProxy ...
+                // }
+                // object ModName extends ModName {}
+                // which leads to us getting the outer class, or
+                // object ModName {
+                //   @SidedProxy ...
+                // }
+                // which leads to us getting the inner class.
+                if (!proxyTarget.getName().endsWith("$"))
+                {
+                    // Get internal class generated by Scala.
+                    proxyTarget = Class.forName(proxyTarget.getName() + "$", true, proxyTarget.getClassLoader());
                 }
             }
+            catch (ClassNotFoundException e)
+            {
+                // Not a singleton, look for @Instance field as a fallback.
+                FMLLog.log(Level.SEVERE, e, "An error occured trying to load a proxy into %s.%s. Did you declare your mod as 'class' instead of 'object'?", proxyTarget.getSimpleName(), target.getName());
+                throw new LoaderException(e);
+            }
+
+            // Get the instance via the MODULE$ field which is
+            // automatically generated by the Scala compiler for
+            // singletons.
+            Object targetInstance = proxyTarget.getField("MODULE$").get(null);
+
+            try
+            {
+                // Find setter function. We do it this way because we can't
+                // necessarily use proxyTarget.getMethod(proxy.getClass()), as
+                // it might be a subclass and not the exact parameter type.
+                // All fields are private in Scala, wrapped by a getter and
+                // setter named <fieldname> and <fieldname>_$eq. To those
+                // familiar with scala.reflect.BeanProperty: these will always
+                // be there, set<Fieldname> and get<Fieldname> will always
+                // only be generated *additionally*.
+                final String setterName = target.getName() + "_$eq";
+                for (Method setter : proxyTarget.getMethods())
+                {
+                    Class<?>[] setterParameters = setter.getParameterTypes();
+                    if (setterName.equals(setter.getName()) &&
+                            // Some more validation.
+                            setterParameters.length == 1 &&
+                            setterParameters[0].isAssignableFrom(proxy.getClass()))
+                    {
+                        // Here goes nothing...
+                        setter.invoke(targetInstance, proxy);
+                        return;
+                    }
+                }
+            }
+            catch (InvocationTargetException e)
+            {
+                FMLLog.log(Level.SEVERE, e, "An error occured trying to load a proxy into %s.%s", proxyTarget.getSimpleName(), target.getName());
+                throw new LoaderException(e);
+            }
+
+            // If we come here we could not find a setter for this proxy.
+            FMLLog.severe("Failed loading proxy into %s.%s, could not find setter function. Did you declare the field with 'val' instead of 'var'?", proxyTarget.getSimpleName(), target.getName());
+            throw new LoaderException();
+        }
+
+        @Override
+        public void setInternalProxies(ModContainer mod, Side side, ClassLoader loader)
+        {
+            // For Scala mods, we want to enable authors to write them like so:
+            // object ModName {
+            //   @SidedProxy(...)
+            //   var proxy: ModProxy = null
+            // }
+            // For this to work, we have to search inside the inner class Scala
+            // generates for singletons, which is in called ModName$. These are
+            // not automatically handled, because the mod discovery code ignores
+            // internal classes.
+            // Note that it is alternatively possible to write this like so:
+            // class ModName {
+            //   @SidedProxy(...)
+            //   var proxy: ModProxy = null
+            // }
+            // object ModName extends ModName { ... }
+            // which will fall back to the normal injection code which calls
+            // setProxy in turn.
+
+            // Get the actual mod implementation, which will be the inner class
+            // if we have a singleton.
+            Class<?> proxyTarget = mod.getMod().getClass();
+            if (proxyTarget.getName().endsWith("$"))
+            {
+                // So we have a singleton class, check if there are targets.
+                for (Field target : proxyTarget.getDeclaredFields())
+                {
+                    // This will not turn up anything if the alternative
+                    // approach was taken (manually declaring the class).
+                    // So we don't initialize the field twice.
+                    if (target.getAnnotation(SidedProxy.class) != null)
+                    {
+                        String targetType = side.isClient() ? target.getAnnotation(SidedProxy.class).clientSide() : target.getAnnotation(SidedProxy.class).serverSide();
+                        try
+                        {
+                            Object proxy = Class.forName(targetType, true, loader).newInstance();
+
+                            if (!target.getType().isAssignableFrom(proxy.getClass()))
+                            {
+                                FMLLog.severe("Attempted to load a proxy type %s into %s.%s, but the types don't match", targetType, proxyTarget.getSimpleName(), target.getName());
+                                throw new LoaderException();
+                            }
+
+                            setProxy(target, proxyTarget, proxy);
+                        }
+                        catch (Exception e) {
+                            FMLLog.log(Level.SEVERE, e, "An error occured trying to load a proxy into %s.%s", proxyTarget.getSimpleName(), target.getName());
+                            throw new LoaderException(e);
+                        }
+                    }
+                }
+            }
+            else
+            {
+                FMLLog.finer("Mod does not appear to be a singleton.");
+            }
+        }
+    }
+
     public static class JavaAdapter implements ILanguageAdapter {
         @Override
         public Object getNewInstance(FMLModContainer container, Class<?> objectClass, ClassLoader classLoader) throws Exception
@@ -48,5 +180,11 @@ public interface ILanguageAdapter {
         {
             target.set(null, proxy);
         }
+
+        @Override
+        public void setInternalProxies(ModContainer mod, Side side, ClassLoader loader)
+        {
+            // Nothing to do here.
+        }
     }
 }

fml/common/cpw/mods/fml/common/ProxyInjector.java

@@ -67,5 +67,8 @@ public class ProxyInjector
                 throw new LoaderException(e);
             }
         }
+
+        // Allow language specific proxy injection.
+        languageAdapter.setInternalProxies(mod, side, mcl);
     }
 }