Enable renaming with flags (#652)

* Enable renaming with flags

The SFTP protocol allows to rename files by specifying
extra flags:

- OVERWRITE
- ATOMIC
- NATIVE

The flags are exposed through a new RenameFlags enum and
can be passed as parameters to the rename() method in
SFTPClient/SFTPEngine.

Relates to #563

* Update RenameFlags.java

* Update RenameFlags.java

* Align license header with all other files

* Make RenameFlags parameter in line with OpenMode(s)

Co-authored-by: Jeroen van Erp <jeroen@hierynomus.com>

src/main/java/net/schmizz/sshj/sftp/RenameFlags.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright (C)2009 - SSHJ Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package net.schmizz.sshj.sftp;
+
+public enum RenameFlags {
+    OVERWRITE(1),
+    ATOMIC(2),
+    NATIVE(4);
+
+    private final long flag;
+
+    RenameFlags(long flag) {
+        this.flag = flag;
+    }
+
+    public long longValue() {
+        return flag;
+    }
+}

src/main/java/net/schmizz/sshj/sftp/SFTPClient.java

@@ -115,9 +115,13 @@ public class SFTPClient
         }
     }
 
-    public void rename(String oldpath, String newpath)
+    public void rename(String oldpath, String newpath) throws IOException {
+        rename(oldpath, newpath, EnumSet.noneOf(RenameFlags.class));
+    }
+
+    public void rename(String oldpath, String newpath, Set<RenameFlags> renameFlags)
             throws IOException {
-        engine.rename(oldpath, newpath);
+        engine.rename(oldpath, newpath, renameFlags);
     }
 
     public void rm(String filename)

src/main/java/net/schmizz/sshj/sftp/SFTPEngine.java

@@ -230,12 +230,18 @@ public class SFTPEngine
         return stat(PacketType.LSTAT, path);
     }
 
-    public void rename(String oldPath, String newPath)
+    public void rename(String oldPath, String newPath, Set<RenameFlags> flags)
             throws IOException {
         if (operativeVersion < 1)
             throw new SFTPException("RENAME is not supported in SFTPv" + operativeVersion);
+
+        long renameFlagMask = 0L;
+        for (RenameFlags flag : flags) {
+            renameFlagMask = renameFlagMask | flag.longValue();
+        }
+
         doRequest(
-                newRequest(PacketType.RENAME).putString(oldPath, sub.getRemoteCharset()).putString(newPath, sub.getRemoteCharset())
+                newRequest(PacketType.RENAME).putString(oldPath, sub.getRemoteCharset()).putString(newPath, sub.getRemoteCharset()).putUInt32(renameFlagMask)
         ).ensureStatusPacketIsOK();
     }
 

src/main/java/net/schmizz/sshj/sftp/StatefulSFTPClient.java

@@ -117,9 +117,9 @@ public class StatefulSFTPClient
     }
 
     @Override
-    public void rename(String oldpath, String newpath)
+    public void rename(String oldpath, String newpath, Set<RenameFlags> renameFlags)
             throws IOException {
-        super.rename(cwdify(oldpath), cwdify(newpath));
+        super.rename(cwdify(oldpath), cwdify(newpath), renameFlags);
     }
 
     @Override