Reorganize export_files

No functional changes.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>

git-remote-hg

@@ -288,25 +288,27 @@ def fix_file_path(path):
     # Git for Windows expects forward
     return path.replace(os.sep, '/')
 
+def export_file(f):
+    fid = node.hex(f.filenode())
+
+    if fid in filenodes:
+        mark = filenodes[fid]
+    else:
+        mark = marks.next_mark()
+        filenodes[fid] = mark
+        d = f.data()
+
+        print("blob")
+        print("mark :%u" % mark)
+        print_data(d)
+
+    path = fix_file_path(f.path())
+    return gitmode(f.flags()), mark, path
+
 def export_files(files):
     final = []
     for f in files:
-        fid = node.hex(f.filenode())
-
-        if fid in filenodes:
-            mark = filenodes[fid]
-        else:
-            mark = marks.next_mark()
-            filenodes[fid] = mark
-            d = f.data()
-
-            print("blob")
-            print("mark :%u" % mark)
-            print_data(d)
-
-        path = fix_file_path(f.path())
-        final.append((gitmode(f.flags()), mark, path))
-
+        final.append(export_file(f))
     return final
 
 def get_filechanges(repo, ctx, parents, files):