Only clone a DIR obj when actually changing it

3 files changed, 29 insertions, 17 deletions

diff --git a/obnamlib/fmt_ga/client.py b/obnamlib/fmt_ga/client.py
index 441b93ea..a795b5dc 100644
--- a/obnamlib/fmt_ga/client.py
+++ b/obnamlib/fmt_ga/client.py
@@ -1,4 +1,4 @@
-# Copyright 2015  Lars Wirzenius
+# Copyright 2015-2016  Lars Wirzenius
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -605,13 +605,17 @@ class GAFileMetadata(object):
                 filename, obnamlib.REPO_FILE_MODE, file_metadata.st_mode)
             self._flush_added_file(filename)
 
-        dir_obj, basename = self._get_mutable_dir_obj(filename)
-        if not dir_obj:
+        dir_obj, _, basename = self._get_dir_obj(filename)
+        if dir_obj is None:
             return False
 
         for key, field in obnamlib.metadata_file_key_mapping:
             value = getattr(file_metadata, field)
-            dir_obj.set_file_key(basename, key, value)
+            old_value = dir_obj.get_file_key(basename, key)
+            if value != old_value:
+                if not dir_obj.is_mutable():
+                    dir_obj, basename = self._get_mutable_dir_obj(filename)
+                dir_obj.set_file_key(basename, key, value)
 
         return True
 
@@ -622,10 +626,13 @@ class GAFileMetadata(object):
                 self._flush_added_file(filename)
             return True
         else:
-            dir_obj, basename = self._get_mutable_dir_obj(filename)
-            if not dir_obj:
+            immutable, _, basename = self._get_dir_obj(filename)
+            if not immutable:
                 return False
-            dir_obj.set_file_key(basename, key, value)
+            old_value = immutable.get_file_key(basename, key)
+            if old_value != value:
+                mutable, basename2 = self._get_mutable_dir_obj(filename)
+                mutable.set_file_key(basename2, key, value)
         return True
 
     def _get_mutable_dir_obj(self, filename):
diff --git a/obnamlib/fmt_ga/dirobj.py b/obnamlib/fmt_ga/dirobj.py
index e98019bd..da67abb9 100644
--- a/obnamlib/fmt_ga/dirobj.py
+++ b/obnamlib/fmt_ga/dirobj.py
@@ -1,4 +1,4 @@
-# Copyright 2015  Lars Wirzenius
+# Copyright 2015-2016  Lars Wirzenius
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -41,19 +41,21 @@ class GADirectory(object):
         self._dict = a_dict
 
     def add_file(self, basename):
-        self._require_mutable()
-        self._dict['metadata'][basename] = {
-            'chunk-ids': [],
-        }
+        if basename not in self._dict['metadata']:
+            self._require_mutable()
+            self._dict['metadata'][basename] = {
+                'chunk-ids': [],
+            }
 
     def _require_mutable(self):
         if not self._mutable:
             raise GAImmutableError()
 
     def remove_file(self, basename):
-        self._require_mutable()
         if basename in self._dict['metadata']:
-            del self._dict['metadata'][basename]
+            self._require_mutable()
+            if basename in self._dict['metadata']:
+                del self._dict['metadata'][basename]
 
     def get_file_basenames(self):
         return self._dict['metadata'].keys()
@@ -63,9 +65,11 @@ class GADirectory(object):
         return self._dict['metadata'][basename].get(key_name)
 
     def set_file_key(self, basename, key, value):
-        self._require_mutable()
         key_name = obnamlib.repo_key_name(key)
-        self._dict['metadata'][basename][key_name] = value
+        old_value = self._dict['metadata'][basename].get(key_name, None)
+        if value != old_value:
+            self._require_mutable()
+            self._dict['metadata'][basename][key_name] = value
 
     def get_file_chunk_ids(self, basename):
         return self._dict['metadata'][basename]['chunk-ids']
diff --git a/obnamlib/fmt_ga/dirobj_tests.py b/obnamlib/fmt_ga/dirobj_tests.py
index c4e8b187..b43324cc 100644
--- a/obnamlib/fmt_ga/dirobj_tests.py
+++ b/obnamlib/fmt_ga/dirobj_tests.py
@@ -1,4 +1,4 @@
-# Copyright 2015  Lars Wirzenius
+# Copyright 2015-2016  Lars Wirzenius
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -66,6 +66,7 @@ class GADirectoryTests(unittest.TestCase):
 
     def test_raises_error_if_immutable_and_file_is_removed(self):
         dir_obj = obnamlib.GADirectory()
+        dir_obj.add_file('README')
         dir_obj.set_immutable()
         self.assertRaises(
             obnamlib.GAImmutableError,