[Wisp] Keep aligning Socket.isConnected() with the normal OpenJDK returning result

Summary: Socket.connect() in Wisp's implemention, uses nio SocketChannel's logic to prevent blocking when Socket is used. However, OpenJDK's isConnected() returns true after successfully connecting even if the socket gets closed. This will cause break accordance so we shall fix this.

Test Plan: newly-added ServerSocketConnectionTest.java

Reviewed-by: D-D-H

Issue: #437

Author: zhengxiaolinX

jdk/src/share/classes/java/net/Socket.java

@@ -597,6 +597,8 @@ SocketImpl getImpl() throws SocketException {
     public void connect(SocketAddress endpoint) throws IOException {
         if (WispEngine.transparentWispSwitch()) {
             asyncImpl.connect(endpoint);
+            // Getting here normally means we have succeeded in the connection
+            connected = true;
             return;
         }
         connect(endpoint, 0);
@@ -637,6 +639,8 @@ public void connect(SocketAddress endpoint, int timeout) throws IOException {
 
         if (WispEngine.transparentWispSwitch()) {
             asyncImpl.connect(endpoint, timeout);
+            // Getting here normally means we have succeeded in the connection
+            connected = true;
             return;
         }
 
@@ -1773,8 +1777,9 @@ public String toString() {
      * @since 1.4
      */
     public boolean isConnected() {
-        if (WispEngine.transparentWispSwitch())
-            return asyncImpl.isConnected();
+        if (WispEngine.transparentWispSwitch()) {
+            return connected;
+        }
 
         // Before 1.3 Sockets were always connected during creation
         return connected || oldImpl;

jdk/test/com/alibaba/wisp/io/ServerSocketConnectionTest.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright (c) 2022 Alibaba Group Holding Limited. All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation. Alibaba designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/*
+ * @test
+ * @summary Test ServerSocket isConnected() method
+ * @requires os.family == "linux"
+ * @library /lib/testlibrary
+ * @run main/othervm -XX:+UnlockExperimentalVMOptions -XX:+EnableCoroutine -XX:+UseWispMonitor -Dcom.alibaba.wisp.transparentWispSwitch=true ServerSocketConnectionTest
+ */
+
+import java.io.IOException;
+import java.net.*;
+import static jdk.testlibrary.Asserts.assertTrue;
+import static jdk.testlibrary.Asserts.assertFalse;
+
+
+public class ServerSocketConnectionTest {
+
+    private static void testIsConnectedAfterClosing() throws Exception {
+        ServerSocket ss = null;
+        Socket s1 = null;
+        InetAddress ia = InetAddress.getLocalHost();
+        try {
+            ss = new ServerSocket(0);
+            ss.setSoTimeout(1000);
+
+            InetSocketAddress isa = new InetSocketAddress(ia, ss.getLocalPort());
+            s1 = new Socket();
+            s1.connect(isa);
+        } catch (Exception e) {
+            e.printStackTrace();
+            throw new RuntimeException("Test Failed!");
+        } finally {
+            // close this socket
+            if (s1 != null) {
+                s1.close();
+                // We should return true even after the socket is closed, to keep align with OpenJDK.
+                assertTrue(s1.isConnected());
+            }
+
+            if (ss != null)  ss.close();
+        }
+    }
+
+    private static void testIsConnectedAfterConnectionFailure() throws Exception {
+        ServerSocket ss = null;
+        Socket s1 = null;
+        InetAddress ia = InetAddress.getLocalHost();
+        try {
+            ss = new ServerSocket(0);
+            ss.setSoTimeout(1000);
+
+            InetSocketAddress isa = new InetSocketAddress(ia, ss.getLocalPort());
+            s1 = new Socket();
+            s1.connect(isa, -1);  // exception here
+        } catch (IOException e) {
+            e.printStackTrace();
+            throw new RuntimeException("Test Failed!");
+        } catch (IllegalArgumentException e) {
+            // we shall go here.
+            assertFalse(s1.isConnected());
+        } finally {
+            if (ss != null)  ss.close();
+            if (s1 != null)  s1.close();
+        }
+    }
+
+    public static void main(String args[]) throws Exception {
+        testIsConnectedAfterClosing();
+        testIsConnectedAfterConnectionFailure();
+    }
+}