Fix a potential fd leak in AbstractDiskHttpData.delete (#10212)

Motivation:

An unexpected IOException may be thrown from `FileChannel.force`. If it happens, the `FileChannel.close` may not be invoked.

Modification:

Place the `FileChannel.close` in a finally block.

Result:

Avoid fd leak.

codec-http/src/main/java/io/netty/handler/codec/http/multipart/AbstractDiskHttpData.java

@@ -250,9 +250,14 @@ public abstract class AbstractDiskHttpData extends AbstractHttpData {
         if (fileChannel != null) {
             try {
                 fileChannel.force(false);
-                fileChannel.close();
             } catch (IOException e) {
-                logger.warn("Failed to close a file.", e);
+                logger.warn("Failed to force.", e);
+            } finally {
+                try {
+                    fileChannel.close();
+                } catch (IOException e) {
+                    logger.warn("Failed to close a file.", e);
+                }
             }
             fileChannel = null;
         }

codec-http/src/test/java/io/netty/handler/codec/http/multipart/DiskFileUploadTest.java

@@ -29,6 +29,9 @@ import java.io.InputStream;
 
 import static org.junit.Assert.assertArrayEquals;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 import static org.junit.Assert.assertTrue;
 
 public class DiskFileUploadTest {
@@ -194,4 +197,22 @@ public class DiskFileUploadTest {
             fis.close();
         }
     }
+
+    @Test
+    public void testDelete() throws Exception {
+        String json = "{\"foo\":\"bar\"}";
+        byte[] bytes = json.getBytes(CharsetUtil.UTF_8);
+        File tmpFile = null;
+        DiskFileUpload f1 = new DiskFileUpload("file4", "file4", "application/json", null, null, 0);
+        try {
+            assertNull(f1.getFile());
+            f1.setContent(Unpooled.wrappedBuffer(bytes));
+            assertNotNull(tmpFile = f1.getFile());
+        } finally {
+            f1.delete();
+            assertNull(f1.getFile());
+            assertNotNull(tmpFile);
+            assertFalse(tmpFile.exists());
+        }
+    }
 }