Add RepositoryFS class

3 files changed, 87 insertions, 0 deletions

diff --git a/obnamlib/__init__.py b/obnamlib/__init__.py
index a7de08dd..41d7c39a 100644
--- a/obnamlib/__init__.py
+++ b/obnamlib/__init__.py
@@ -97,6 +97,7 @@ from vfs import (
     NEW_FILE_MODE)
 from vfs_local import LocalFS
 from fsck_work_item import WorkItem
+from repo_fs import RepositoryFS
 from lockmgr import LockManager
 from forget_policy import ForgetPolicy
 from app import App, ObnamIOError, ObnamSystemError
diff --git a/obnamlib/repo_fs.py b/obnamlib/repo_fs.py
new file mode 100644
index 00000000..053496c0
--- /dev/null
+++ b/obnamlib/repo_fs.py
@@ -0,0 +1,85 @@
+# Copyright 2015  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
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# =*= License: GPL-3+ =*=
+
+
+import os
+
+import tracing
+
+
+class RepositoryFS(object):
+
+    '''A wrapper around a VFS object, with calls to hooks.
+
+    This is exactly like a full VFS implementation, but it only wraps
+    another instance and provides read/write hooks. The hooks are
+    intended for filtering data read from or written to the
+    repository, which is then used to implement things like
+    compression and encryption.
+
+    FIXME: Some day this might offer only the subset of the full VFS
+    that is necessary for repository access, to allow easier
+    implementation of new repository storage methods.
+
+    '''
+
+    def __init__(self, repo, fs, hooks):
+        self.repo = repo
+        self.fs = fs
+        self.hooks = hooks
+
+    def __getattr__(self, name):
+        return getattr(self.fs, name)
+
+    def _get_toplevel(self, filename):
+        parts = filename.split(os.sep)
+        if len(parts) >= 1:
+            return parts[0]
+        else: # pragma: no cover
+            raise ToplevelIsFileError(filename=filename)
+
+    def cat(self, filename, runfilters=True):
+        data = self.fs.cat(filename)
+        if not runfilters: # pragma: no cover
+            return data
+        toplevel = self._get_toplevel(filename)
+        return self.hooks.filter_read('repository-data', data,
+                                      repo=self.repo, toplevel=toplevel)
+
+    def lock(self, filename, data):
+        self.fs.lock(filename, data)
+
+    def create_and_init_toplevel(self, filename):
+        tracing.trace('filename=%s', filename)
+        toplevel = self._get_toplevel(filename)
+        if not self.fs.exists(toplevel):
+            self.fs.mkdir(toplevel)
+            self.hooks.call('repository-toplevel-init', self.repo, toplevel)
+
+    def write_file(self, filename, data, runfilters=True):
+        toplevel = self._get_toplevel(filename)
+        if runfilters:
+            data = self.hooks.filter_write('repository-data', data,
+                                           repo=self.repo, toplevel=toplevel)
+        self.fs.write_file(filename, data)
+
+    def overwrite_file(self, filename, data, runfilters=True):
+        toplevel = self._get_toplevel(filename)
+        if runfilters:
+            data = self.hooks.filter_write('repository-data', data,
+                                           repo=self.repo, toplevel=toplevel)
+        self.fs.overwrite_file(filename, data)
diff --git a/without-tests b/without-tests
index 9f171a82..98c28d66 100644
--- a/without-tests
+++ b/without-tests
@@ -5,6 +5,7 @@ obnamlib/humanise.py
 obnamlib/fsck_work_item.py
 obnamlib/repo_interface.py
 obnamlib/vfs.py
+obnamlib/repo_fs.py
 obnamlib/fmt_6/__init__.py
 obnamlib/fmt_6/repo_tree.py
 obnamlib/plugins/__init__.py