CouchDatabase refactoring and indexing.

CouchDatabase now inherits from u1db InMemoryDatabase, so it can use all
available facilities. The important thing is to make sure every modification
of logs or indexes gets propagated to the ObjectStore backend.

1 files changed, 58 insertions, 11 deletions

diff --git a/backends/couch.py b/backends/couch.py
index 8ba42d78..c8dadfa8 100644
--- a/backends/couch.py
+++ b/backends/couch.py
@@ -1,6 +1,8 @@
 import uuid
 from base64 import b64encode, b64decode
+from u1db import errors
 from u1db.sync import LocalSyncTarget
+from u1db.backends.inmemory import InMemoryIndex
 from couchdb.client import Server, Document as CouchDocument
 from couchdb.http import ResourceNotFound
 from leap.soledad.backends.objectstore import ObjectStore
@@ -36,7 +38,7 @@ class CouchDatabase(ObjectStore):
         super(CouchDatabase, self).__init__(replica_uid=replica_uid)
 
     #-------------------------------------------------------------------------
-    # implemented methods from Database
+    # methods from Database
     #-------------------------------------------------------------------------
 
     def _get_doc(self, doc_id, check_for_conflicts=False):
@@ -95,6 +97,23 @@ class CouchDatabase(ObjectStore):
     def get_sync_target(self):
         return CouchSyncTarget(self)
 
+    def create_index(self, index_name, *index_expressions):
+        if index_name in self._indexes:
+            if self._indexes[index_name]._definition == list(
+                    index_expressions):
+                return
+            raise errors.IndexNameTakenError
+        index = InMemoryIndex(index_name, list(index_expressions))
+        for doc_id in self._database:
+            if doc_id == self.U1DB_DATA_DOC_ID:
+                continue
+            doc = self._get_doc(doc_id)
+            if doc.content is not None:
+                index.add_json(doc_id, doc.get_json())
+        self._indexes[index_name] = index
+        # save data in object store
+        self._set_u1db_data()
+
     def close(self):
         # TODO: fix this method so the connection is properly closed and
         # test_close (+tearDown, which deletes the db) works without problems.
@@ -110,35 +129,47 @@ class CouchDatabase(ObjectStore):
         return Synchronizer(self, CouchSyncTarget(url, creds=creds)).sync(
             autocreate=autocreate)
 
-    def _initialize(self):
+    #-------------------------------------------------------------------------
+    # methods from ObjectStore
+    #-------------------------------------------------------------------------
+
+    def _init_u1db_data(self):
         if self._replica_uid is None:
             self._replica_uid = uuid.uuid4().hex
         doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
-        doc.content = {'sync_log': [],
-                       'transaction_log': [],
-                       'conflict_log': b64encode(json.dumps([])),
+        doc.content = {'transaction_log': [],
+                       'conflicts': b64encode(json.dumps({})),
+                       'other_generations': {},
+                       'indexes': b64encode(json.dumps({})),
                        'replica_uid': self._replica_uid}
         self._put_doc(doc)
 
     def _get_u1db_data(self):
+        # retrieve u1db data from couch db
         cdoc = self._database.get(self.U1DB_DATA_DOC_ID)
         jsonstr = self._database.get_attachment(cdoc, 'u1db_json').getvalue()
         content = json.loads(jsonstr)
-        self._sync_log.log = content['sync_log']
-        self._transaction_log.log = content['transaction_log']
-        self._conflict_log.log = json.loads(b64decode(content['conflict_log']))
+        # set u1db database info
+        #self._sync_log = content['sync_log']
+        self._transaction_log = content['transaction_log']
+        self._conflicts = json.loads(b64decode(content['conflicts']))
+        self._other_generations = content['other_generations']
+        self._indexes = self._load_indexes_from_json(
+            b64decode(content['indexes']))
         self._replica_uid = content['replica_uid']
+        # save couch _rev
         self._couch_rev = cdoc['_rev']
 
     def _set_u1db_data(self):
         doc = self._factory(doc_id=self.U1DB_DATA_DOC_ID)
         doc.content = {
-            'sync_log': self._sync_log.log,
-            'transaction_log': self._transaction_log.log,
+            'transaction_log': self._transaction_log,
             # Here, the b64 encode ensures that document content
             # does not cause strange behaviour in couchdb because
             # of encoding.
-            'conflict_log': b64encode(json.dumps(self._conflict_log.log)),
+            'conflicts': b64encode(json.dumps(self._conflicts)),
+            'other_generations': self._other_generations,
+            'indexes': b64encode(self._dump_indexes_as_json()),
             'replica_uid': self._replica_uid,
             '_rev': self._couch_rev}
         self._put_doc(doc)
@@ -150,6 +181,22 @@ class CouchDatabase(ObjectStore):
     def delete_database(self):
         del(self._server[self._dbname])
 
+    def _dump_indexes_as_json(self):
+        indexes = {}
+        for name, idx in self._indexes.iteritems():
+            indexes[name] = {}
+            for attr in ['name', 'definition', 'values']:
+                indexes[name][attr] = getattr(idx, '_' + attr)
+        return json.dumps(indexes)
+
+    def _load_indexes_from_json(self, indexes):
+        dict = {}
+        for name, idx_dict in json.loads(indexes).iteritems():
+            idx = InMemoryIndex(name, idx_dict['definition'])
+            idx._values = idx_dict['values']
+            dict[name] = idx
+        return dict
+
 
 class CouchSyncTarget(LocalSyncTarget):