From 98d0a34c88fe9854681e5730219dd1082c98e0c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=B6rg=20Prante?= <joergprante@gmail.com>
Date: Fri, 22 Sep 2023 16:27:40 +0200
Subject: [PATCH] more work on nio event loop

---
 .../org/xbib/event/loop/nio/NioEventLoop.java | 75 +++++++++++--------
 1 file changed, 42 insertions(+), 33 deletions(-)

diff --git a/src/main/java/org/xbib/event/loop/nio/NioEventLoop.java b/src/main/java/org/xbib/event/loop/nio/NioEventLoop.java
index e40792c..f0750ae 100644
--- a/src/main/java/org/xbib/event/loop/nio/NioEventLoop.java
+++ b/src/main/java/org/xbib/event/loop/nio/NioEventLoop.java
@@ -8,6 +8,7 @@ import org.xbib.event.loop.SingleThreadEventLoop;
 import org.xbib.event.util.IntSupplier;
 
 import java.io.IOException;
+import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Field;
 import java.nio.channels.CancelledKeyException;
 import java.nio.channels.SelectableChannel;
@@ -15,14 +16,8 @@ import java.nio.channels.Selector;
 import java.nio.channels.SelectionKey;
 
 import java.nio.channels.spi.SelectorProvider;
-import java.security.AccessController;
-import java.security.PrivilegedAction;
-import java.util.ArrayList;
-import java.util.Collection;
-import java.util.Iterator;
 import java.util.Objects;
 import java.util.Queue;
-import java.util.Set;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.logging.Level;
@@ -155,8 +150,7 @@ public final class NioEventLoop extends SingleThreadEventLoop {
         }
 
         // ensure the current selector implementation is what we can instrument.
-        if (maybeSelectorImplClass == null ||
-            !maybeSelectorImplClass.isAssignableFrom(unwrappedSelector.getClass())) {
+        if (maybeSelectorImplClass == null || !maybeSelectorImplClass.isAssignableFrom(unwrappedSelector.getClass())) {
             return new SelectorTuple(unwrappedSelector);
         }
 
@@ -167,40 +161,19 @@ public final class NioEventLoop extends SingleThreadEventLoop {
         try {
             Field selectedKeysField = selectorImplClass.getDeclaredField("selectedKeys");
             Field publicSelectedKeysField = selectorImplClass.getDeclaredField("publicSelectedKeys");
-
-            if (PlatformDependent.javaVersion() >= 9 && PlatformDependent.hasUnsafe()) {
-                // Let us try to use sun.misc.Unsafe to replace the SelectionKeySet.
-                // This allows us to also do this in Java9+ without any extra flags.
-                long selectedKeysFieldOffset = PlatformDependent.objectFieldOffset(selectedKeysField);
-                long publicSelectedKeysFieldOffset =
-                        PlatformDependent.objectFieldOffset(publicSelectedKeysField);
-
-                if (selectedKeysFieldOffset != -1 && publicSelectedKeysFieldOffset != -1) {
-                    PlatformDependent.putObject(
-                            unwrappedSelector, selectedKeysFieldOffset, selectedKeySet);
-                    PlatformDependent.putObject(
-                            unwrappedSelector, publicSelectedKeysFieldOffset, selectedKeySet);
-                    return null;
-                }
-                // We could not retrieve the offset, lets try reflection as last-resort.
-            }
-
-            Throwable cause = ReflectionUtil.trySetAccessible(selectedKeysField, true);
+            Throwable cause = trySetAccessible(selectedKeysField, true);
             if (cause != null) {
-                return cause;
+                maybeException = cause;
             }
-            cause = ReflectionUtil.trySetAccessible(publicSelectedKeysField, true);
+            cause = trySetAccessible(publicSelectedKeysField, true);
             if (cause != null) {
-                return cause;
+                maybeException = cause;
             }
-
             selectedKeysField.set(unwrappedSelector, selectedKeySet);
             publicSelectedKeysField.set(unwrappedSelector, selectedKeySet);
-            return null;
         } catch (NoSuchFieldException | IllegalAccessException e) {
            maybeException = e;
         }
-
         if (maybeException instanceof Exception) {
             selectedKeys = null;
             Exception e = (Exception) maybeException;
@@ -763,4 +736,40 @@ public final class NioEventLoop extends SingleThreadEventLoop {
             logger.log(Level.WARNING, "Failed to update SelectionKeys.", t);
         }
     }
+
+    private static Throwable trySetAccessible(AccessibleObject object, boolean checkAccessible) {
+        if (checkAccessible && !isExplicitTryReflectionSetAccessible()) {
+            return new UnsupportedOperationException("Reflective setAccessible(true) disabled");
+        }
+        try {
+            object.setAccessible(true);
+            return null;
+        } catch (SecurityException e) {
+            return e;
+        }
+    }
+    private static boolean isExplicitTryReflectionSetAccessible() {
+        // we disable reflective access
+        boolean defaultValue = javaVersion() < 9 || System.getProperties().containsKey("org.graalvm.nativeimage.imagecode");
+        return Boolean.parseBoolean(System.getProperties().getProperty("io.netty.tryReflectionSetAccessible",
+                Boolean.toString(defaultValue)));
+    }
+
+    private static int javaVersion() {
+        return majorVersion(System.getProperties().getProperty("java.specification.version", "1.6"));
+    }
+
+    private static int majorVersion(String javaSpecVersion) {
+        final String[] components = javaSpecVersion.split("\\.");
+        final int[] version = new int[components.length];
+        for (int i = 0; i < components.length; i++) {
+            version[i] = Integer.parseInt(components[i]);
+        }
+        if (version[0] == 1) {
+            assert version[1] >= 6;
+            return version[1];
+        } else {
+            return version[0];
+        }
+    }
 }