1 files changed, 55 insertions, 0 deletions
diff --git a/muck/pers.py b/muck/pers.py
new file mode 100644
index 0000000..aa4f4c1
--- /dev/null
+++ b/muck/pers.py
@@ -0,0 +1,55 @@
+# Copyright (C) 2018  Lars Wirzenius
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+import json
+import os
+
+import muck
+
+
+class PersistentStore:
+
+    def __init__(self, dirname):
+        self._dirname = dirname
+        self._log = ChangeLogWriter(self._changelog_filename())
+
+    def _changelog_filename(self):
+        return os.path.join(self._dirname, 'changelog')
+
+    def append_change(self, chg):
+        self._log.append(chg)
+
+    def load_memory_store(self):
+        ms = muck.MemoryStore()
+        for chg in self._changelog_reader():
+            ms.change(chg)
+        return ms
+
+    def _changelog_reader(self):
+        with open(self._changelog_filename()) as f:
+            for line in f:
+                entry = json.loads(line.strip())
+                yield muck.create_change_from_log_entry(entry)
+
+
+class ChangeLogWriter:
+
+    def __init__(self, filename):
+        mode = os.O_WRONLY | os.O_APPEND | os.O_CREAT
+        self._fd = os.open(filename, mode, 0o666)
+
+    def append(self, chg):
+        line = json.dumps(chg.as_dict())
+        os.write(self._fd, line.encode('UTF-8'))