Replace rm with faster rsync --delete with empty src dir

ccollect

@@ -160,16 +160,28 @@ delete_from_file()
     file="$1"; shift
     suffix="" # It will be set, if deleting incomplete backups.
     [ $# -eq 1 ] && suffix="$1" && shift
+    # dirs for deletion will be moved to this trash dir inside destination dir
+    # - for fast mv operation
+    trash="$(mktemp -d "trash.XXXXXX")"
     while read to_remove; do
+        mv "${to_remove}" "${trash}" ||
+            _exit_err "Moving ${to_remove} to ${trash} failed."
         set -- "$@" "${to_remove}"
         if [ "${suffix}" ]; then
             to_remove_no_suffix="$(echo ${to_remove} | sed "s/$suffix\$//")"
+            mv "${to_remove_no_suffix}" "${trash}" ||
+                _exit_err "Moving ${to_remove_no_suffix} to ${trash} failed."
             set -- "$@" "${to_remove_no_suffix}"
         fi
     done < "${file}"
-    _techo "Removing $@ ..."
-    [ "${VVERBOSE}" ] && echo rm "$@"
-    rm -rf "$@" || _exit_err "Removing $@ failed."
+    _techo "Removing $@ in ${trash}..."
+    empty_dir="empty-dir"
+    mkdir "${empty_dir}" || _exit_err "Empty directory ${empty_dir} cannot be created."
+    [ "${VVERBOSE}" ] && echo "rsync -a --delete ${empty_dir} ${trash}"
+    # rsync needs ending slash for directory content
+    rsync -a --delete "${empty_dir}/" "${trash}/" || _exit_err "Removing $@ failed."
+    rmdir "${trash}" || _exit_err "Removing ${trash} directory failed"
+    rmdir "${empty_dir}" || _exit_err "Removing ${empty_dir} directory failed"
 }
 
 display_version()

doc/changes/next

@@ -0,0 +1 @@
+* Performance: replace rm -rf with faster rsync --delete empty src dir