1 files changed, 76 insertions, 0 deletions
diff --git a/ick2/trans.py b/ick2/trans.py
new file mode 100644
index 0000000..a66dd41
--- /dev/null
+++ b/ick2/trans.py
@@ -0,0 +1,76 @@
+# 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 ick2
+
+
+class TransactionalResource:
+
+    def __init__(self, state, kind, rid):
+        self.state = state
+        self.kind = kind
+        self.rid = rid
+        if state.has_resource(kind, rid):
+            self.resource = state.get_resource(kind, rid)
+        else:
+            self.resource = ick2.resource_from_dict({})
+
+        methods = [
+            'as_dict',
+            '__getitem__',
+            '__setitem__',
+            '__contains__',
+            '__len__',
+        ]
+        for method in methods:
+            setattr(self, method, getattr(self.resource, method))
+
+    def __enter__(self):
+        return self.resource
+
+    def __exit__(self, exc_type, value, traceback):
+        if exc_type is None:
+            self.state.write_resource(self.kind, self.rid, self.resource)
+
+
+class TransactionalState:
+
+    def __init__(self, state):
+        self.state = state
+
+    def new(self, kind, rid):
+        return TransactionalResource(self.state, kind, rid)
+
+    def modify(self, kind, rid):
+        return TransactionalResource(self.state, kind, rid)
+
+    def get_resource_kinds(self):
+        return self.state.get_resource_kinds()
+
+    def get_resource_ids(self, kind):
+        return self.state.get_resource_ids(kind)
+
+    def has_resource(self, kind, rid):
+        return self.state.has_resource(kind, rid)
+
+    def get_resource(self, kind, rid):
+        return self.state.get_resource(kind, rid)
+
+    def get_resources(self, kind):
+        return self.state.get_resources(kind)
+
+    def remove_resource(self, kind, rid):
+        self.state.remove_resource(kind, rid)