From 0c00bef71e586c6b5c601fc47baf33d10ea4f04c Mon Sep 17 00:00:00 2001
From: Oleg Kalnichevski <olegk@apache.org>
Date: Thu, 6 Oct 2011 13:07:33 +0000
Subject: [PATCH] HTTPCLIENT-1127: fixed dead-lock between
 SingleClientConnManager and AbstractPooledConnAdapter

git-svn-id: https://svn.apache.org/repos/asf/httpcomponents/httpclient/trunk@1179609 13f79535-47bb-0310-9956-ffa450edef68
---
 .../impl/conn/AbstractClientConnAdapter.java  | 45 +++++++++----------
 .../impl/conn/AbstractPooledConnAdapter.java  |  2 +-
 2 files changed, 23 insertions(+), 24 deletions(-)

diff --git a/httpclient/src/main/java/org/apache/http/impl/conn/AbstractClientConnAdapter.java b/httpclient/src/main/java/org/apache/http/impl/conn/AbstractClientConnAdapter.java
index 802af2489..cfb9af216 100644
--- a/httpclient/src/main/java/org/apache/http/impl/conn/AbstractClientConnAdapter.java
+++ b/httpclient/src/main/java/org/apache/http/impl/conn/AbstractClientConnAdapter.java
@@ -78,7 +78,7 @@ public abstract class AbstractClientConnAdapter implements ManagedClientConnecti
      * This attribute MUST NOT be final, so the adapter can be detached
      * from the connection manager without keeping a hard reference there.
      */
-    private volatile ClientConnectionManager connManager;
+    private final ClientConnectionManager connManager;
 
     /** The wrapped connection. */
     private volatile OperatedClientConnection wrappedConnection;
@@ -114,9 +114,8 @@ public abstract class AbstractClientConnAdapter implements ManagedClientConnecti
      * Detaches this adapter from the wrapped connection.
      * This adapter becomes useless.
      */
-    protected synchronized void detach() {
+    protected void detach() {
         wrappedConnection = null;
-        connManager = null; // base class attribute
         duration = Long.MAX_VALUE;
     }
 
@@ -303,32 +302,32 @@ public abstract class AbstractClientConnAdapter implements ManagedClientConnecti
         }
     }
 
-    public synchronized void releaseConnection() {
-        if (released) {
-            return;
-        }
-        released = true;
-        if (connManager != null) {
+    public void releaseConnection() {
+        synchronized (connManager) {
+            if (released) {
+                return;
+            }
+            released = true;
             connManager.releaseConnection(this, duration, TimeUnit.MILLISECONDS);
         }
     }
 
-    public synchronized void abortConnection() {
-        if (released) {
-            return;
-        }
-        released = true;
-        unmarkReusable();
-        try {
-            shutdown();
-        } catch (IOException ignore) {
-        }
-        if (connManager != null) {
+    public void abortConnection() {
+        synchronized (connManager) {
+            if (released) {
+                return;
+            }
+            released = true;
+            unmarkReusable();
+            try {
+                shutdown();
+            } catch (IOException ignore) {
+            }
             connManager.releaseConnection(this, duration, TimeUnit.MILLISECONDS);
         }
     }
 
-    public synchronized Object getAttribute(final String id) {
+    public Object getAttribute(final String id) {
         OperatedClientConnection conn = getWrappedConnection();
         assertValid(conn);
         if (conn instanceof HttpContext) {
@@ -338,7 +337,7 @@ public abstract class AbstractClientConnAdapter implements ManagedClientConnecti
         }
     }
 
-    public synchronized Object removeAttribute(final String id) {
+    public Object removeAttribute(final String id) {
         OperatedClientConnection conn = getWrappedConnection();
         assertValid(conn);
         if (conn instanceof HttpContext) {
@@ -348,7 +347,7 @@ public abstract class AbstractClientConnAdapter implements ManagedClientConnecti
         }
     }
 
-    public synchronized void setAttribute(final String id, final Object obj) {
+    public void setAttribute(final String id, final Object obj) {
         OperatedClientConnection conn = getWrappedConnection();
         assertValid(conn);
         if (conn instanceof HttpContext) {
diff --git a/httpclient/src/main/java/org/apache/http/impl/conn/AbstractPooledConnAdapter.java b/httpclient/src/main/java/org/apache/http/impl/conn/AbstractPooledConnAdapter.java
index 1fa5de72b..4748ee297 100644
--- a/httpclient/src/main/java/org/apache/http/impl/conn/AbstractPooledConnAdapter.java
+++ b/httpclient/src/main/java/org/apache/http/impl/conn/AbstractPooledConnAdapter.java
@@ -105,7 +105,7 @@ public abstract class AbstractPooledConnAdapter extends AbstractClientConnAdapte
      * This adapter becomes useless.
      */
     @Override
-    protected synchronized void detach() {
+    protected void detach() {
         poolEntry = null;
         super.detach();
     }