srmclient: fix srmfs 'get permission' command

Motivation:

The srmfs 'get permission' command has several problems:
  1. the output includes eronous space in 'group' output,
  2. it fails to show 'owner' permissions when owner is unknown,
  3. it has potential to throw NullPointerException,
  4. it fails to show the 'other' permissions.

Modification:

Update code to fix these issues.

Result:

More detailed and accurate output that is more robust.

Target: master
Request: 3.0
Requires-notes: no
Requires-srmclient-notes: yes
Requires-book: no
Patch: https://rb.dcache.org/r/9896/
Acked-by: Gerd Behrmann

modules/srm-client/src/main/java/org/dcache/srm/shell/SrmShell.java

@@ -1385,22 +1385,28 @@ private void append(PrintWriter writer, String prefix, TPermissionReturn permiss
             if (status != null && status.getStatusCode() != TStatusCode.SRM_SUCCESS) {
                 writer.append(prefix).println(status.getExplanation());
             } else {
-                String owner = permission.getOwner();
-                if (owner != null) {
-                    append(writer, prefix, "owner", permission.getOwnerPermission(), owner);
+                if (permission.getOwnerPermission() != null) {
+                    append(writer, prefix, "owner", permission.getOwnerPermission(), permission.getOwner());
                 }
-                for (TUserPermission p : permission.getArrayOfUserPermissions().getUserPermissionArray()) {
-                    append(writer, prefix, "user ", p.getMode(), p.getUserID());
+                if (permission.getArrayOfUserPermissions() != null) {
+                    for (TUserPermission p : permission.getArrayOfUserPermissions().getUserPermissionArray()) {
+                        append(writer, prefix, "user", p.getMode(), p.getUserID());
+                    }
+                }
+                if (permission.getArrayOfGroupPermissions() != null) {
+                    for (TGroupPermission p : permission.getArrayOfGroupPermissions().getGroupPermissionArray()) {
+                        append(writer, prefix, "group", p.getMode(), p.getGroupID());
+                    }
                 }
-                for (TUserPermission p : permission.getArrayOfUserPermissions().getUserPermissionArray()) {
-                    append(writer, prefix, "user ", p.getMode(), p.getUserID());
+                if (permission.getOtherPermission() != null) {
+                    append(writer, prefix, "other", permission.getOtherPermission(), "");
                 }
             }
         }
 
-        private void append(PrintWriter writer, String prefix, String type, TPermissionMode mode, String user)
+        private void append(PrintWriter writer, String prefix, String type, TPermissionMode mode, String name)
         {
-            writer.append(prefix).append(permissionsFor(mode)).append(' ').append(type).append(' ').println(user);
+            writer.append(prefix).append(permissionsFor(mode)).append(' ').append(type).append(' ').println(name == null ? "(unknown)" : name);
         }
     }