Only allow changes to a mutable GADirectory

4 files changed, 51 insertions, 1 deletions

diff --git a/obnamlib/__init__.py b/obnamlib/__init__.py
index 673a2312..77bf961d 100644
--- a/obnamlib/__init__.py
+++ b/obnamlib/__init__.py
@@ -185,6 +185,7 @@ from fmt_ga import (
     GAClientList,
     GAClient,
     GADirectory,
+    GAImmutableError,
     create_gadirectory_from_dict,
     GATree,
     GAChunkStore,
diff --git a/obnamlib/fmt_ga/__init__.py b/obnamlib/fmt_ga/__init__.py
index d3eb21c9..dc710d5c 100644
--- a/obnamlib/fmt_ga/__init__.py
+++ b/obnamlib/fmt_ga/__init__.py
@@ -19,7 +19,7 @@
 from .client_list import GAClientList
 from .chunk_store import GAChunkStore
 from .indexes import GAChunkIndexes
-from .dirobj import GADirectory, create_gadirectory_from_dict
+from .dirobj import GADirectory, GAImmutableError, create_gadirectory_from_dict
 from .tree import GATree
 from .client import GAClient
 from .format import RepositoryFormatGA
diff --git a/obnamlib/fmt_ga/dirobj.py b/obnamlib/fmt_ga/dirobj.py
index 32e997b0..989a7954 100644
--- a/obnamlib/fmt_ga/dirobj.py
+++ b/obnamlib/fmt_ga/dirobj.py
@@ -16,6 +16,9 @@
 # =*= License: GPL-3+ =*=
 
 
+import obnamlib
+
+
 class GADirectory(object):
 
     def __init__(self):
@@ -35,9 +38,15 @@ class GADirectory(object):
         return self._dict
 
     def add_file(self, basename):
+        self._require_mutable()
         self._dict['metadata'][basename] = {}
 
+    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]
 
@@ -48,15 +57,18 @@ class GADirectory(object):
         return self._dict['metadata'][basename].get(key)
 
     def set_file_key(self, basename, key, value):
+        self._require_mutable()
         self._dict['metadata'][basename][key] = value
 
     def get_subdir_basenames(self):
         return self._dict['subdirs'].keys()
 
     def add_subdir(self, basename, obj_id):
+        self._require_mutable()
         self._dict['subdirs'][basename] = obj_id
 
     def remove_subdir(self, basename):
+        self._require_mutable()
         if basename in self._dict['subdirs']:
             del self._dict['subdirs'][basename]
 
@@ -64,6 +76,11 @@ class GADirectory(object):
         return self._dict['subdirs'][basename]
 
 
+class GAImmutableError(obnamlib.ObnamError):
+
+    msg = 'Attempt to modify an immutable GADirectory'
+
+
 def create_gadirectory_from_dict(a_dict):
     dir_obj = GADirectory()
     for basename in a_dict['metadata']:
diff --git a/obnamlib/fmt_ga/dirobj_tests.py b/obnamlib/fmt_ga/dirobj_tests.py
index 04f634c6..43e36869 100644
--- a/obnamlib/fmt_ga/dirobj_tests.py
+++ b/obnamlib/fmt_ga/dirobj_tests.py
@@ -46,6 +46,11 @@ class GADirectoryTests(unittest.TestCase):
         dir_obj.add_file('README')
         self.assertEqual(dir_obj.get_file_basenames(), ['README'])
 
+    def test_raises_error_if_immutable_and_file_is_added(self):
+        dir_obj = obnamlib.GADirectory()
+        dir_obj.set_immutable()
+        self.assertRaises(obnamlib.GAImmutableError, dir_obj.add_file, 'README')
+
     def test_removes_file(self):
         dir_obj = obnamlib.GADirectory()
         dir_obj.add_file('README')
@@ -57,6 +62,11 @@ class GADirectoryTests(unittest.TestCase):
         dir_obj.remove_file('README')
         self.assertEqual(dir_obj.get_file_basenames(), [])
 
+    def test_raises_error_if_immutable_and_file_is_removed(self):
+        dir_obj = obnamlib.GADirectory()
+        dir_obj.set_immutable()
+        self.assertRaises(obnamlib.GAImmutableError, dir_obj.remove_file, 'README')
+
     def test_gets_file_key_when_unset(self):
         dir_obj = obnamlib.GADirectory()
         dir_obj.add_file('README')
@@ -72,6 +82,14 @@ class GADirectoryTests(unittest.TestCase):
             dir_obj.get_file_key('README', obnamlib.REPO_FILE_MODE),
             0123)
 
+    def test_raises_error_if_muutable_and_file_key_is_set(self):
+        dir_obj = obnamlib.GADirectory()
+        dir_obj.add_file('README')
+        dir_obj.set_immutable()
+        self.assertRaises(
+            obnamlib.GAImmutableError,
+            dir_obj.set_file_key, 'README', obnamlib.REPO_FILE_MODE, 0123)
+
     def test_has_no_subdirs_initially(self):
         dir_obj = obnamlib.GADirectory()
         self.assertEqual(dir_obj.get_subdir_basenames(), [])
@@ -81,6 +99,13 @@ class GADirectoryTests(unittest.TestCase):
         dir_obj.add_subdir('.git', 'obj-id')
         self.assertEqual(dir_obj.get_subdir_basenames(), ['.git'])
 
+    def test_raises_error_if_mutable_and_subdir_is_added(self):
+        dir_obj = obnamlib.GADirectory()
+        dir_obj.set_immutable()
+        self.assertRaises(
+            obnamlib.GAImmutableError,
+            dir_obj.add_subdir, '.git', 'obj-id')
+
     def test_removes_subdir(self):
         dir_obj = obnamlib.GADirectory()
         dir_obj.add_subdir('.git', 'obj-id')
@@ -92,6 +117,13 @@ class GADirectoryTests(unittest.TestCase):
         dir_obj.remove_subdir('.git')
         self.assertEqual(dir_obj.get_subdir_basenames(), [])
 
+    def test_raises_error_if_mutable_and_subdir_is_removed(self):
+        dir_obj = obnamlib.GADirectory()
+        dir_obj.set_immutable()
+        self.assertRaises(
+            obnamlib.GAImmutableError,
+            dir_obj.remove_subdir, '.git')
+
     def test_returns_subdir_object_id(self):
         dir_obj = obnamlib.GADirectory()
         dir_obj.add_subdir('.git', 'obj-id')