1 files changed, 150 insertions, 0 deletions
diff --git a/ick2/persistent.py b/ick2/persistent.py
new file mode 100644
index 0000000..1d79e3d
--- /dev/null
+++ b/ick2/persistent.py
@@ -0,0 +1,150 @@
+# Copyright (C) 2018-2019  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 copy
+import os
+import urllib.parse
+
+
+import yaml
+
+
+import ick2
+
+
+class PersistentStateInterface:  # pragma: no cover
+
+    def get_resource_ids(self, kind):
+        raise NotImplementedError()
+
+    def has_resource(self, kind, rid):
+        raise NotImplementedError()
+
+    def get_resource(self, kind, rid):
+        raise NotImplementedError()
+
+    def get_resources(self, kind):
+        return [
+            self.get_resource(kind, rid)
+            for rid in self.get_resource_ids(kind)
+        ]
+
+    def write_resource(self, kind, rid, resource):
+        raise NotImplementedError()
+
+    def remove_resource(self, kind, rid):
+        raise NotImplementedError()
+
+
+class FilePersistentState(PersistentStateInterface):
+
+    def __init__(self):
+        self._dir = None
+
+    def get_directory(self):
+        return self._dir
+
+    def set_directory(self, dirname):
+        self._dir = dirname
+
+    def _safe(self, name):
+        return urllib.parse.quote(name, safe='')
+
+    def _unsafe(self, safe):
+        return urllib.parse.unquote(safe)
+
+    def _unsafe_list(self, safe_names):
+        return [self._unsafe(safe) for safe in safe_names]
+
+    def _dirname(self, kind):
+        return os.path.join(self._dir, self._safe(kind))
+
+    def _filename(self, kind, rid):
+        dirname = self._dirname(kind)
+        return os.path.join(dirname, self._safe(rid))
+
+    def has_resource(self, kind, rid):
+        filename = self._filename(kind, rid)
+        return os.path.exists(filename)
+
+    def get_resource_ids(self, kind):
+        dirname = self._dirname(kind)
+        if os.path.exists(dirname):
+            return self._unsafe_list(os.listdir(dirname))
+        return []
+
+    def get_resource(self, kind, rid):
+        filename = self._filename(kind, rid)
+        if not os.path.exists(filename):
+            raise ick2.NotFound(kind=kind, rid=rid)
+        with open(filename, 'r') as f:
+            as_dict = yaml.load(f, Loader=yaml.CSafeLoader)
+            return resource_from_dict(as_dict)
+
+    def write_resource(self, kind, rid, resource):
+        dirname = self._dirname(kind)
+        if not os.path.exists(dirname):
+            os.makedirs(dirname)
+
+        filename = self._filename(kind, rid)
+        with open(filename, 'w') as f:
+            yaml.dump(
+                resource.as_dict(), stream=f, Dumper=yaml.CSafeDumper)
+
+    def remove_resource(self, kind, rid):
+        filename = self._filename(kind, rid)
+        os.remove(filename)
+
+
+class NotFound(Exception):
+
+    def __init__(self, kind, rid):
+        super().__init__(
+            'Resource {}:{} not found'.format(
+                kind or "unknown", rid or "unknown"))
+
+
+class Resource:  # pragma: no cover
+
+    def __init__(self, as_dict=None):
+        self._dict = copy.deepcopy(as_dict or {})
+
+    def as_dict(self):
+        return copy.deepcopy(self._dict)
+
+    def __getitem__(self, key):
+        return self._dict[key]
+
+    def __setitem__(self, key, value):
+        self._dict[key] = value
+
+    def __contains__(self, key):
+        return key in self._dict
+
+    def __len__(self):
+        return len(self._dict)
+
+    def get(self, key, default=None):
+        return self._dict.get(key, default)
+
+    def from_dict(self, as_dict):
+        self._dict.clear()
+        for key in as_dict:
+            self[key] = as_dict[key]
+
+
+def resource_from_dict(as_dict):  # pragma: no cover
+    return Resource(as_dict)