diff --git a/hgitaly/diff.py b/hgitaly/diff.py
index afe520dad77e7a344e6b9b136d0e979af5cddff2_aGdpdGFseS9kaWZmLnB5..d8e570c487794a66fac4a6739b9ea28a0544c29b_aGdpdGFseS9kaWZmLnB5 100644
--- a/hgitaly/diff.py
+++ b/hgitaly/diff.py
@@ -152,3 +152,12 @@
             break
     return b''.join(headerlines)
 
+
+def additions_deletions(header):
+    """Return number of lines added and deleted in a patch header."""
+    adds, dels = 0, 0
+    for hunk in header.hunks:
+        add_count, del_count = hunk.countchanges(hunk.hunk)
+        adds += add_count
+        dels += del_count
+    return adds, dels
diff --git a/hgitaly/service/diff.py b/hgitaly/service/diff.py
index afe520dad77e7a344e6b9b136d0e979af5cddff2_aGdpdGFseS9zZXJ2aWNlL2RpZmYucHk=..d8e570c487794a66fac4a6739b9ea28a0544c29b_aGdpdGFseS9zZXJ2aWNlL2RpZmYucHk= 100644
--- a/hgitaly/service/diff.py
+++ b/hgitaly/service/diff.py
@@ -21,6 +21,7 @@
     parse_diff_request_cid,
     exportsingle,
     insert_blob_index,
+    additions_deletions,
 )
 from mercurial import (
     copies,
@@ -532,16 +533,6 @@
     return (True, repo, ctx_from, ctx_to)
 
 
-def additions_deletions(header):
-    """Return number of lines added and deleted in a patch header."""
-    adds, dels = 0, 0
-    for hunk in header.hunks:
-        add_count, del_count = hunk.countchanges(hunk.hunk)
-        adds += add_count
-        dels += del_count
-    return adds, dels
-
-
 def commit_delta_size(delta):
     size = (
         len(delta.from_id) + len(delta.to_id)