From 6143626427670b167b54501ead1a4ee50a3dcdc2 Mon Sep 17 00:00:00 2001
From: Norman Maurer <nmaurer@redhat.com>
Date: Fri, 12 Oct 2012 07:45:00 +0200
Subject: [PATCH] Cleanup of sctp code based on comments in #633

---
 .../sctp/SctpMessageToMessageEncoder.java     | 36 --------
 .../aio/MethodHandleAioChannelFinder.java     | 84 +++++++++++++++++++
 2 files changed, 84 insertions(+), 36 deletions(-)
 delete mode 100644 codec/src/main/java/io/netty/handler/codec/sctp/SctpMessageToMessageEncoder.java
 create mode 100644 transport/src/main/java/io/netty/channel/socket/aio/MethodHandleAioChannelFinder.java

diff --git a/codec/src/main/java/io/netty/handler/codec/sctp/SctpMessageToMessageEncoder.java b/codec/src/main/java/io/netty/handler/codec/sctp/SctpMessageToMessageEncoder.java
deleted file mode 100644
index fe94baa6fc..0000000000
--- a/codec/src/main/java/io/netty/handler/codec/sctp/SctpMessageToMessageEncoder.java
+++ /dev/null
@@ -1,36 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-
-package io.netty.handler.codec.sctp;
-
-import io.netty.buffer.ByteBuf;
-import io.netty.channel.ChannelHandlerContext;
-import io.netty.channel.socket.SctpMessage;
-import io.netty.handler.codec.MessageToMessageEncoder;
-
-public abstract class SctpMessageToMessageEncoder<I> extends MessageToMessageEncoder<I, SctpMessage> {
-
-    /**
-     * Returns {@code true} if and only if the specified message can be encoded by this encoder.
-     *
-     * @param msg the message
-     */
-    public boolean isEncodable(Object msg) throws Exception {
-        return true;
-    }
-
-    public abstract SctpMessage encode(ChannelHandlerContext ctx, I msg) throws Exception;
-}
diff --git a/transport/src/main/java/io/netty/channel/socket/aio/MethodHandleAioChannelFinder.java b/transport/src/main/java/io/netty/channel/socket/aio/MethodHandleAioChannelFinder.java
new file mode 100644
index 0000000000..b4d8b593be
--- /dev/null
+++ b/transport/src/main/java/io/netty/channel/socket/aio/MethodHandleAioChannelFinder.java
@@ -0,0 +1,84 @@
+/*
+ * Copyright 2012 The Netty Project
+ *
+ * The Netty Project licenses this file to you under the Apache License,
+ * version 2.0 (the "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at:
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+package io.netty.channel.socket.aio;
+
+import java.lang.invoke.MethodHandle;
+import java.lang.invoke.MethodHandles;
+import java.lang.reflect.Field;
+import java.util.HashMap;
+import java.util.Map;
+
+public class MethodHandleAioChannelFinder implements AioChannelFinder {
+    private static volatile Map<Class<?>, MethodHandle> handleCache = new HashMap<Class<?>, MethodHandle>();
+
+    @Override
+    public AbstractAioChannel findChannel(Runnable command) throws Exception {
+        MethodHandle handle;
+        for (;;) {
+            handle = findHandle(command);
+            if (handle == null) {
+                return null;
+            }
+            Object next;
+            try {
+                next = handle.invokeExact();
+            } catch (Throwable e) {
+                e.printStackTrace();
+                throw new Exception("Unable to invoke handle " + handle, e);
+            }
+            if (next instanceof AbstractAioChannel) {
+                return (AbstractAioChannel) next;
+            }
+            command = (Runnable) next;
+        }
+    }
+
+    private static MethodHandle findHandle(Object command) throws Exception {
+        Map<Class<?>, MethodHandle> handleCache = MethodHandleAioChannelFinder.handleCache;
+        Class<?> commandType = command.getClass();
+        MethodHandle res = handleCache.get(commandType);
+        if (res != null) {
+            return res;
+        }
+
+        for (Field f: commandType.getDeclaredFields()) {
+            if (f.getType() == Runnable.class) {
+                return put(handleCache, commandType, f);
+            }
+
+            // Check against the actual class as this is what will be used by the jdk
+            // if you use a final variable and pass it to a Runnable
+            if (f.getType().isAssignableFrom(AbstractAioChannel.class)
+                    || f.getType() == Object.class) {
+                f.setAccessible(true);
+                Object candidate = f.get(command);
+                if (candidate instanceof AbstractAioChannel) {
+                    return put(handleCache, commandType, f);
+                }
+            }
+        }
+        return null;
+    }
+
+    private static MethodHandle put(Map<Class<?>, MethodHandle> oldCache, Class<?> key, Field value) throws Exception {
+        MethodHandle handle = MethodHandles.lookup().findGetter(key, value.getName(), value.getType());
+        Map<Class<?>, MethodHandle> newCache = new HashMap<Class<?>, MethodHandle>(oldCache.size());
+        newCache.putAll(oldCache);
+        newCache.put(key, handle);
+        handleCache = newCache;
+        return handle;
+    }
+}