Change: how controller stores persistent data

Replace old State class with new FilePersistentState and
TransactionalState classes. Use new Resource class instead of raw
dicts. Use context managers for creating, updating resources, to avoid
mistakes from accidentally not saving changes.

Overall persistence should now be rather simpler. This should open up
a possibility for changing the controller to insert more actions into
the build graph, to trigger notifcations via the workers.

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)