Centralize path cache handling

trans/mixins.py

@@ -110,18 +110,33 @@ class PathMixin(object):
     '''
     Mixin for path manipulations.
     '''
+    _dir_path = None
+
+    def _get_path(self):
+        '''
+        Actual calculation of path.
+        '''
+        raise NotImplementedError()
+
     def get_path(self):
         '''
         Return path to directory.
+
+        Caching is really necessary for linked project, otherwise
+        we end up fetching linked subproject again and again.
         '''
-        raise NotImplementedError()
+        if self._dir_path is None:
+            self._dir_path = self._get_path()
+
+        return self._dir_path
 
     def check_rename(self, old):
         '''
         Detects slug changes and possibly renames underlaying directory.
         '''
         if old.slug != self.slug:
-            os.rename(
-                old.get_path(),
-                self.get_path()
-            )
+            old_path = old.get_path()
+            # Invalidate cache
+            self._dir_path = None
+            new_path = self.get_path()
+            os.rename(old_path, new_path)

trans/models/project.py

@@ -262,7 +262,7 @@ class Project(models.Model, PercentMixin, URLMixin, PathMixin):
             [subproject.locked for subproject in self.subproject_set.all()]
         )
 
-    def get_path(self):
+    def _get_path(self):
         return os.path.join(appsettings.GIT_ROOT, self.slug)
 
     def __unicode__(self):

trans/models/subproject.py

@@ -236,7 +236,6 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
         self._file_format = None
         self._template_store = None
         self._percents = None
-        self._dir_path = None
 
     def has_acl(self, user):
         '''
@@ -286,22 +285,14 @@ class SubProject(models.Model, PercentMixin, URLMixin, PathMixin):
     def get_full_slug(self):
         return '%s__%s' % (self.project.slug, self.slug)
 
-    def get_path(self):
+    def _get_path(self):
         '''
         Returns full path to subproject git repository.
-
-        Caching is really necessary for linked project, otherwise
-        we end up fetching linked subproject again and again.
         '''
-        if self._dir_path is None:
-            if self.is_repo_link():
-                self._dir_path = self.linked_subproject.get_path()
-            else:
-                self._dir_path = os.path.join(
-                    self.project.get_path(), self.slug
-                )
-
-        return self._dir_path
+        if self.is_repo_link():
+            return self.linked_subproject.get_path()
+        else:
+            return os.path.join(self.project.get_path(), self.slug)
 
     def get_git_lock_path(self):
         '''