[mina-sshd] 01/02: Use ThreadLocal.remove() instead of ThreadLocal.set(null)

[twolf]

This is an automated email from the ASF dual-hosted git repository.

twolf pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/mina-sshd.git

commit 4037290a0849abc65dececd66ac1a6bdc5ba1cd9
Author: Thomas Wolf <tw...@apache.org>
AuthorDate: Sun Oct 30 00:07:05 2022 +0200

    Use ThreadLocal.remove() instead of ThreadLocal.set(null)
    
    ThreadLocal.set(null) keeps a reference to the ThreadLocal instance in
    the thread, which can lead to (small) memory leaks when threads are
    re-used, for instance via thread pools.
---
 .../sshd/common/util/threads/ThreadUtils.java      | 26 +++++++++++++---------
 .../apache/sshd/sftp/client/fs/SftpFileSystem.java |  2 +-
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git 
a/sshd-common/src/main/java/org/apache/sshd/common/util/threads/ThreadUtils.java
 
b/sshd-common/src/main/java/org/apache/sshd/common/util/threads/ThreadUtils.java
index d06da9f69..b93e81ed5 100644
--- 
a/sshd-common/src/main/java/org/apache/sshd/common/util/threads/ThreadUtils.java
+++ 
b/sshd-common/src/main/java/org/apache/sshd/common/util/threads/ThreadUtils.java
@@ -60,12 +60,15 @@ public final class ThreadUtils {
      * @see              {@link #isInternal()}
      */
     public static <V> V runAsInternal(Callable<V> code) throws Exception {
-        Boolean initial = IS_INTERNAL_THREAD.get();
-        try {
-            IS_INTERNAL_THREAD.set(Boolean.TRUE);
+        if (isInternalThread()) {
             return code.call();
-        } finally {
-            IS_INTERNAL_THREAD.set(initial);
+        } else {
+            try {
+                IS_INTERNAL_THREAD.set(Boolean.TRUE);
+                return code.call();
+            } finally {
+                IS_INTERNAL_THREAD.remove();
+            }
         }
     }
 
@@ -82,12 +85,15 @@ public final class ThreadUtils {
      * @see              {@link #isInternal()}
      */
     public static <T, V> V runAsInternal(T param, IOFunction<? super T, V> 
code) throws IOException {
-        Boolean initial = IS_INTERNAL_THREAD.get();
-        try {
-            IS_INTERNAL_THREAD.set(Boolean.TRUE);
+        if (isInternalThread()) {
             return code.apply(param);
-        } finally {
-            IS_INTERNAL_THREAD.set(initial);
+        } else {
+            try {
+                IS_INTERNAL_THREAD.set(Boolean.TRUE);
+                return code.apply(param);
+            } finally {
+                IS_INTERNAL_THREAD.remove();
+            }
         }
     }
 
diff --git 
a/sshd-sftp/src/main/java/org/apache/sshd/sftp/client/fs/SftpFileSystem.java 
b/sshd-sftp/src/main/java/org/apache/sshd/sftp/client/fs/SftpFileSystem.java
index 47f999758..ae8049285 100644
--- a/sshd-sftp/src/main/java/org/apache/sshd/sftp/client/fs/SftpFileSystem.java
+++ b/sshd-sftp/src/main/java/org/apache/sshd/sftp/client/fs/SftpFileSystem.java
@@ -298,7 +298,7 @@ public class SftpFileSystem
                 if (!pool.offer(delegate)) {
                     delegate.close();
                 }
-                wrappers.set(null);
+                wrappers.remove();
             }
         }