Only release FileRegion after transfer was done if its configured to do

so. The default is true in the master branch. See NETTY-440

src/main/java/org/jboss/netty/channel/DefaultFileRegion.java

@@ -14,13 +14,28 @@ public class DefaultFileRegion implements FileRegion {
     private final FileChannel file;
     private final long position;
     private final long count;
+    private boolean releaseAfterTransfer;
 
-    public DefaultFileRegion(FileChannel file, long position, long count) {
+    public DefaultFileRegion(FileChannel file, long position, long count, boolean releaseAfterTransfer) {
         this.file = file;
         this.position = position;
         this.count = count;
+        this.releaseAfterTransfer = releaseAfterTransfer;
     }
 
+    /**
+     * Calls {@link #DefaultFileRegion(FileChannel, long, long, boolean)} with <code>true</code>
+     * as the last argument.
+     * 
+     * @param file
+     * @param position
+     * @param count
+     */
+    public DefaultFileRegion(FileChannel file, long position, long count) {
+        this(file, position, count, true);
+    }
+    
+
     @Override
     public long getPosition() {
         return position;
@@ -54,4 +69,13 @@ public class DefaultFileRegion implements FileRegion {
             logger.warn("Failed to close a file.", e);
         }
     }
+
+    @Override
+    public boolean releaseAfterTransfer() {
+        return releaseAfterTransfer;
+    }
+    
+    public void setReleaseAfterTransfer(boolean releaseAfterTransfer) {
+        this.releaseAfterTransfer = releaseAfterTransfer;
+    }
 }

src/main/java/org/jboss/netty/channel/FileRegion.java

@@ -84,4 +84,12 @@ public interface FileRegion extends ExternalResourceReleasable {
      *                  byte of the region transferred.
      */
     long transferTo(WritableByteChannel target, long position) throws IOException;
+    
+    /**
+     * Returns <code>true</code> if {@link #releaseExternalResources()} should be called after the
+     * transfer of the {@link FileRegion} was complete.
+     * 
+     * @return release
+     */
+    public boolean releaseAfterTransfer();
 }

src/main/java/org/jboss/netty/channel/socket/nio/SocketSendBufferPool.java

@@ -306,8 +306,10 @@ final class SocketSendBufferPool {
 
         @Override
         public void release() {
-            // Make sure the FileRegion resource are released otherwise it may cause a FD leak or something similar
-            file.releaseExternalResources(); 
+            if (file.releaseAfterTransfer()) {
+                // Make sure the FileRegion resource are released otherwise it may cause a FD leak or something similar
+                file.releaseExternalResources(); 
+            }
         }
     }
 

src/main/java/org/jboss/netty/channel/socket/oio/OioWorker.java

@@ -141,7 +141,9 @@ class OioWorker implements Runnable {
                         }
                     }
                 } finally {
-                    fr.releaseExternalResources();
+                    if (fr.releaseAfterTransfer()) {
+                        fr.releaseExternalResources();
+                    }
 
                 }
             } else {