Add GATree

1 files changed, 101 insertions, 0 deletions

diff --git a/obnamlib/fmt_ga/tree.py b/obnamlib/fmt_ga/tree.py
new file mode 100644
index 00000000..bd175b2a
--- /dev/null
+++ b/obnamlib/fmt_ga/tree.py
@@ -0,0 +1,101 @@
+# 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 obnamlib
+
+
+class GATree(object):
+
+    def __init__(self):
+        self._blob_store = None
+        self._dir_objs = {}
+        self._root_dir_id = None
+
+    def set_blob_store(self, blob_store):
+        self._blob_store = blob_store
+
+    def set_root_directory_id(self, root_dir_id):
+        self._root_dir_id = root_dir_id
+
+    def get_root_directory_id(self):
+        return self._root_dir_id
+
+    def get_directory(self, pathname):
+        if pathname in self._dir_objs:
+            return self._dir_objs[pathname]
+
+        if self._root_dir_id is None:
+            return None
+
+        if pathname == '/':
+            return self._get_dir_obj(self._root_dir_id)
+
+        parent_path = os.path.dirname(pathname)
+        parent_obj = self.get_directory(parent_path)
+        if parent_obj is None:  # pragma: no cover
+            return None
+        obj_id = parent_obj.get_subdir_object_id(os.path.basename(pathname))
+        if obj_id is None:  # pragma: no cover
+            return None
+        return self._get_dir_obj(obj_id)
+
+    def _get_dir_obj(self, dir_id):
+        blob = self._blob_store.get_blob(dir_id)
+        if blob is None:  # pragma: no cover
+            return None
+        as_dict = obnamlib.deserialise_object(blob)
+        dir_obj = obnamlib.create_gadirectory_from_dict(as_dict)
+        dir_obj.set_immutable()
+        return dir_obj
+
+    def set_directory(self, pathname, dir_obj):
+        self._dir_objs[pathname] = dir_obj
+        if pathname != '/':
+            parent_path = os.path.dirname(pathname)
+            parent_obj = self.get_directory(parent_path)
+            if not parent_obj:
+                parent_obj = self._create_fake_parent(
+                    os.path.basename(pathname), dir_obj)
+                self.set_directory(parent_path, parent_obj)
+
+    def _create_fake_parent(self, subdir_basename, subdir_obj):
+        parent_obj = obnamlib.GADirectory()
+        parent_obj.add_subdir(subdir_basename, None)
+        return parent_obj
+
+    def flush(self):
+        self._root_dir_id = self._fixup_subdir_refs('/')
+        self._blob_store.flush()
+        self._dir_objs = {}
+
+    def _fixup_subdir_refs(self, pathname):
+        dir_obj = self._dir_objs[pathname]
+        for basename in dir_obj.get_subdir_basenames():
+            if dir_obj.get_subdir_object_id(basename) is None:
+                assert dir_obj.is_mutable()
+                subdir_path = os.path.join(pathname, basename)
+                subdir_id = self._fixup_subdir_refs(subdir_path)
+                dir_obj.add_subdir(basename, subdir_id)
+        return self._put_dir_obj(dir_obj)
+
+    def _put_dir_obj(self, dir_obj):
+        dir_obj.set_immutable()
+        blob = obnamlib.serialise_object(dir_obj.as_dict())
+        return self._blob_store.put_blob(blob)