Issue #6556 Ensure context classloader set when operating on memcache.

Signed-off-by: Jan Bartel <janb@webtide.com>

jetty-memcached/jetty-memcached-sessions/src/main/java/org/eclipse/jetty/memcached/session/MemcachedSessionDataMap.java

@@ -21,6 +21,7 @@
 import net.rubyeye.xmemcached.MemcachedClient;
 import net.rubyeye.xmemcached.XMemcachedClientBuilder;
 import net.rubyeye.xmemcached.transcoders.SerializingTranscoder;
+import org.eclipse.jetty.server.session.RunnableResult;
 import org.eclipse.jetty.server.session.SessionContext;
 import org.eclipse.jetty.server.session.SessionData;
 import org.eclipse.jetty.server.session.SessionDataMap;
@@ -43,6 +44,7 @@ public class MemcachedSessionDataMap extends AbstractLifeCycle implements Sessio
     protected int _expirySec = 0;
     protected boolean _heartbeats = true;
     protected XMemcachedClientBuilder _builder;
+    protected SessionContext _context;
 
     /**
      * SessionDataTranscoder
@@ -140,9 +142,13 @@ public void setHeartbeats(boolean heartbeats)
     @Override
     public void initialize(SessionContext context)
     {
+        if (isStarted())
+            throw new IllegalStateException("Context set after MemcachedSessionDataMap started");
+
         try
         {
-            _builder.setTranscoder(new SessionDataTranscoder());
+            _context = context;
+            _builder.setTranscoder(new SessionDataTranscoder(_context.getContext().getClassLoader()));
             _client = _builder.build();
             _client.setEnableHeartBeat(isHeartbeats());
         }
@@ -155,14 +161,47 @@ public void initialize(SessionContext context)
     @Override
     public SessionData load(String id) throws Exception
     {
-        SessionData data = _client.get(id);
-        return data;
+        if (!isStarted())
+            throw new IllegalStateException("Not started");
+
+        final RunnableResult<SessionData> result = new RunnableResult<>();
+
+        Runnable r = () ->
+        {
+            try
+            {
+                result.setResult(_client.get(id));
+            }
+            catch (Exception e)
+            {
+                result.setException(e);
+            }
+        };
+
+        _context.run(r);
+        return result.getOrThrow();
     }
 
     @Override
     public void store(String id, SessionData data) throws Exception
     {
-        _client.set(id, _expirySec, data);
+        if (!isStarted())
+            throw new IllegalStateException("Not started");
+
+        final RunnableResult<Object> result = new RunnableResult<>();
+        Runnable r = () ->
+        {
+            try
+            {
+                _client.set(id, _expirySec, data);
+            }
+            catch (Exception e)
+            {
+                result.setException(e);
+            }
+        };
+        _context.run(r);
+        result.throwIfException();
     }
 
     @Override

jetty-server/src/main/java/org/eclipse/jetty/server/session/AbstractSessionDataStore.java

@@ -40,41 +40,6 @@ public abstract class AbstractSessionDataStore extends ContainerLifeCycle implem
     protected long _lastOrphanSweepTime = 0; //last time in ms that we deleted orphaned sessions
     protected int _savePeriodSec = DEFAULT_SAVE_PERIOD_SEC; //time in sec between saves
 
-    /**
-     * Small utility class to allow us to
-     * return a result and an Exception
-     * from invocation of Runnables.
-     *
-     * @param <V> the type of the result.
-     */
-    private class Result<V>
-    {
-        private V _result;
-        private Exception _exception;
-
-        public void setResult(V result)
-        {
-            _result = result;
-        }
-
-        public void setException(Exception exception)
-        {
-            _exception = exception;
-        }
-
-        private void throwIfException() throws Exception
-        {
-            if (_exception != null)
-                throw _exception;
-        }
-
-        public V getOrThrow() throws Exception
-        {
-            throwIfException();
-            return _result;
-        }
-    }
-
     /**
      * Check if a session for the given id exists.
      * 
@@ -171,7 +136,7 @@ public SessionData load(String id) throws Exception
         if (!isStarted())
             throw new IllegalStateException("Not started");
 
-        final Result<SessionData> result = new Result<>();
+        final RunnableResult<SessionData> result = new RunnableResult<>();
 
         Runnable r = () ->
         {
@@ -214,7 +179,7 @@ public void store(String id, SessionData data) throws Exception
             //set the last saved time to now
             data.setLastSaved(System.currentTimeMillis());
 
-            final Result<Object> result = new Result<>();
+            final RunnableResult<Object> result = new RunnableResult<>();
             Runnable r = () ->
             {
                 try
@@ -238,7 +203,7 @@ public void store(String id, SessionData data) throws Exception
     @Override
     public boolean exists(String id) throws Exception
     {
-        Result<Boolean> result = new Result<>();
+        RunnableResult<Boolean> result = new RunnableResult<>();
         Runnable r = () ->
         {
             try

jetty-server/src/main/java/org/eclipse/jetty/server/session/RunnableResult.java

@@ -0,0 +1,49 @@
+//
+// ========================================================================
+// Copyright (c) 1995-2021 Mort Bay Consulting Pty Ltd and others.
+//
+// This program and the accompanying materials are made available under the
+// terms of the Eclipse Public License v. 2.0 which is available at
+// https://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+// which is available at https://www.apache.org/licenses/LICENSE-2.0.
+//
+// SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+// ========================================================================
+//
+
+package org.eclipse.jetty.server.session;
+
+/**
+ * Small utility class to allow us to
+ * return a result and an Exception
+ * from invocation of Runnables.
+ *
+ * @param <V> the type of the result.
+ */
+public class RunnableResult<V>
+{
+    private V _result;
+    private Exception _exception;
+
+    public void setResult(V result)
+    {
+        _result = result;
+    }
+
+    public void setException(Exception exception)
+    {
+        _exception = exception;
+    }
+
+    public void throwIfException() throws Exception
+    {
+        if (_exception != null)
+            throw _exception;
+    }
+
+    public V getOrThrow() throws Exception
+    {
+        throwIfException();
+        return _result;
+    }
+}