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.

2 files changed, 96 insertions, 391 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):
 
diff --git a/backends/objectstore.py b/backends/objectstore.py
index d72a2ecc..588fc7a1 100644
--- a/backends/objectstore.py
+++ b/backends/objectstore.py
@@ -1,77 +1,35 @@
-from u1db.backends import CommonBackend
-from u1db import errors, Document, vectorclock
+from u1db.backends.inmemory import InMemoryDatabase
+from u1db import errors
 
 
-class ObjectStore(CommonBackend):
+class ObjectStore(InMemoryDatabase):
     """
     A backend for storing u1db data in an object store.
     """
 
     def __init__(self, replica_uid=None):
-        # This initialization method should be called after the connection
-        # with the database is established in each implementation, so it can
-        # ensure that u1db data is configured and up-to-date.
-        self.set_document_factory(Document)
-        self._sync_log = SyncLog()
-        self._transaction_log = TransactionLog()
-        self._conflict_log = ConflictLog(self._factory)
-        self._replica_uid = replica_uid
-        self._ensure_u1db_data()
+        super(ObjectStore, self).__init__(replica_uid)
+        # sync data in memory with data in object store
+        if not self._get_doc(self.U1DB_DATA_DOC_ID):
+            self._init_u1db_data()
+        self._get_u1db_data()
 
     #-------------------------------------------------------------------------
-    # implemented methods from Database
+    # methods from Database
     #-------------------------------------------------------------------------
 
-    def set_document_factory(self, factory):
-        self._factory = factory
-
-    def set_document_size_limit(self, limit):
-        raise NotImplementedError(self.set_document_size_limit)
-
-    def whats_changed(self, old_generation=0):
-        self._get_u1db_data()
-        return self._transaction_log.whats_changed(old_generation)
-
-    def get_doc(self, doc_id, include_deleted=False):
-        doc = self._get_doc(doc_id, check_for_conflicts=True)
-        if doc is None:
-            return None
-        if doc.is_tombstone() and not include_deleted:
-            return None
-        return doc
+    def _set_replica_uid(self, replica_uid):
+        super(ObjectStore, self)._set_replica_uid(replica_uid)
+        self._set_u1db_data()
 
     def _put_doc(self, doc):
         raise NotImplementedError(self._put_doc)
 
-    def _update_gen_and_transaction_log(self, doc_id):
-        new_gen = self._get_generation() + 1
-        trans_id = self._allocate_transaction_id()
-        self._transaction_log.append((new_gen, doc_id, trans_id))
-        self._set_u1db_data()
+    def _get_doc(self, doc):
+        raise NotImplementedError(self._get_doc)
 
-    def put_doc(self, doc):
-        # consistency check
-        if doc.doc_id is None:
-            raise errors.InvalidDocId()
-        self._check_doc_id(doc.doc_id)
-        self._check_doc_size(doc)
-        # check if document exists
-        old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
-        if old_doc and old_doc.has_conflicts:
-            raise errors.ConflictedDoc()
-        if old_doc and doc.rev is None and old_doc.is_tombstone():
-            new_rev = self._allocate_doc_rev(old_doc.rev)
-        else:
-            if old_doc is not None:
-                if old_doc.rev != doc.rev:
-                    raise errors.RevisionConflict()
-            else:
-                if doc.rev is not None:
-                    raise errors.RevisionConflict()
-            new_rev = self._allocate_doc_rev(doc.rev)
-        doc.rev = new_rev
-        self._put_and_update_indexes(old_doc, doc)
-        return doc.rev
+    def get_all_docs(self, include_deleted=False):
+        raise NotImplementedError(self.get_all_docs)
 
     def delete_doc(self, doc):
         old_doc = self._get_doc(doc.doc_id, check_for_conflicts=True)
@@ -89,130 +47,49 @@ class ObjectStore(CommonBackend):
         self._put_and_update_indexes(old_doc, doc)
         return new_rev
 
-    # start of index-related methods: these are not supported by this backend.
+    # index-related methods
 
     def create_index(self, index_name, *index_expressions):
-        return False
+        raise NotImplementedError(self.create_index)
 
     def delete_index(self, index_name):
-        return False
-
-    def list_indexes(self):
-        return []
-
-    def get_from_index(self, index_name, *key_values):
-        return []
-
-    def get_range_from_index(self, index_name, start_value=None,
-                             end_value=None):
-        return []
-
-    def get_index_keys(self, index_name):
-        return []
-
-    # end of index-related methods: these are not supported by this backend.
-
-    def get_doc_conflicts(self, doc_id):
-        self._get_u1db_data()
-        conflict_docs = self._conflict_log.get_conflicts(doc_id)
-        if not conflict_docs:
-            return []
-        this_doc = self._get_doc(doc_id)
-        this_doc.has_conflicts = True
-        return [this_doc] + list(conflict_docs)
-
-    def resolve_doc(self, doc, conflicted_doc_revs):
-        cur_doc = self._get_doc(doc.doc_id)
-        new_rev = self._ensure_maximal_rev(cur_doc.rev,
-                                           conflicted_doc_revs)
-        superseded_revs = set(conflicted_doc_revs)
-        doc.rev = new_rev
-        if cur_doc.rev in superseded_revs:
-            self._put_and_update_indexes(cur_doc, doc)
-        else:
-            self._add_conflict(doc.doc_id, new_rev, doc.get_json())
-        self._delete_conflicts(doc, superseded_revs)
-
-    def _get_replica_gen_and_trans_id(self, other_replica_uid):
-        self._get_u1db_data()
-        return self._sync_log.get_replica_gen_and_trans_id(other_replica_uid)
+        super(ObjectStore, self).delete_index(index_name)
+        self._set_u1db_data()
 
-    def _set_replica_gen_and_trans_id(self, other_replica_uid,
-                                      other_generation, other_transaction_id):
-        return self._do_set_replica_gen_and_trans_id(
-            other_replica_uid,
-            other_generation,
-            other_transaction_id)
+    def _replace_conflicts(self, doc, conflicts):
+        super(ObjectStore, self)._replace_conflicts(doc, conflicts)
+        self._set_u1db_data()
 
     def _do_set_replica_gen_and_trans_id(self, other_replica_uid,
                                          other_generation,
                                          other_transaction_id):
-        self._sync_log.set_replica_gen_and_trans_id(other_replica_uid,
-                                                    other_generation,
-                                                    other_transaction_id)
+        super(ObjectStore, self)._do_set_replica_gen_and_trans_id(
+            other_replica_uid,
+            other_generation,
+            other_transaction_id)
         self._set_u1db_data()
 
-    def _get_transaction_log(self):
-        self._get_u1db_data()
-        return self._transaction_log.get_transaction_log()
-
     #-------------------------------------------------------------------------
     # implemented methods from CommonBackend
     #-------------------------------------------------------------------------
 
-    def _get_generation(self):
-        self._get_u1db_data()
-        return self._transaction_log.get_generation()
-
-    def _get_generation_info(self):
-        self._get_u1db_data()
-        return self._transaction_log.get_generation_info()
-
-    def _has_conflicts(self, doc_id):
-        self._get_u1db_data()
-        return self._conflict_log.has_conflicts(doc_id)
-
     def _put_and_update_indexes(self, old_doc, doc):
-        # for now we ignore indexes as this backend is used to store encrypted
-        # blobs of data in the server.
+        for index in self._indexes.itervalues():
+            if old_doc is not None and not old_doc.is_tombstone():
+                index.remove_json(old_doc.doc_id, old_doc.get_json())
+            if not doc.is_tombstone():
+                index.add_json(doc.doc_id, doc.get_json())
+        trans_id = self._allocate_transaction_id()
         self._put_doc(doc)
-        self._update_gen_and_transaction_log(doc.doc_id)
-
-    def _get_trans_id_for_gen(self, generation):
-        self._get_u1db_data()
-        trans_id = self._transaction_log.get_trans_id_for_gen(generation)
-        if trans_id is None:
-            raise errors.InvalidGeneration
-        return trans_id
+        self._transaction_log.append((doc.doc_id, trans_id))
+        self._set_u1db_data()
 
     #-------------------------------------------------------------------------
     # methods specific for object stores
     #-------------------------------------------------------------------------
 
-    def _ensure_u1db_data(self):
-        """
-        Guarantee that u1db data (logs and replica info) exists in store.
-        """
-        if not self._is_initialized():
-            self._initialize()
-        self._get_u1db_data()
-
     U1DB_DATA_DOC_ID = 'u1db_data'
 
-    def _is_initialized(self):
-        """
-        Verify if u1db data exists in store.
-        """
-        if not self._get_doc(self.U1DB_DATA_DOC_ID):
-            return False
-        return True
-
-    def _initialize(self):
-        """
-        Create u1db data object in store.
-        """
-        NotImplementedError(self._initialize)
-
     def _get_u1db_data(self):
         """
         Fetch u1db configuration data from backend storage.
@@ -225,227 +102,8 @@ class ObjectStore(CommonBackend):
         """
         NotImplementedError(self._set_u1db_data)
 
-    def _set_replica_uid(self, replica_uid):
-        self._replica_uid = replica_uid
-        self._set_u1db_data()
-
-    def _get_replica_uid(self):
-        return self._replica_uid
-
-    replica_uid = property(
-        _get_replica_uid, _set_replica_uid, doc="Replica UID of the database")
-
-    #-------------------------------------------------------------------------
-    # The methods below were cloned from u1db sqlite backend. They should at
-    # least exist and raise a NotImplementedError exception in CommonBackend
-    # (should we maybe fill a bug in u1db bts?).
-    #-------------------------------------------------------------------------
-
-    def _add_conflict(self, doc_id, my_doc_rev, my_content):
-        self._conflict_log.append((doc_id, my_doc_rev, my_content))
-        self._set_u1db_data()
-
-    def _delete_conflicts(self, doc, conflict_revs):
-        deleting = [(doc.doc_id, c_rev) for c_rev in conflict_revs]
-        self._conflict_log.delete_conflicts(deleting)
-        self._set_u1db_data()
-        doc.has_conflicts = self._has_conflicts(doc.doc_id)
-
-    def _prune_conflicts(self, doc, doc_vcr):
-        if self._has_conflicts(doc.doc_id):
-            autoresolved = False
-            c_revs_to_prune = []
-            for c_doc in self._conflict_log.get_conflicts(doc.doc_id):
-                c_vcr = vectorclock.VectorClockRev(c_doc.rev)
-                if doc_vcr.is_newer(c_vcr):
-                    c_revs_to_prune.append(c_doc.rev)
-                elif doc.same_content_as(c_doc):
-                    c_revs_to_prune.append(c_doc.rev)
-                    doc_vcr.maximize(c_vcr)
-                    autoresolved = True
-            if autoresolved:
-                doc_vcr.increment(self._replica_uid)
-                doc.rev = doc_vcr.as_str()
-            self._delete_conflicts(doc, c_revs_to_prune)
-
-    def _force_doc_sync_conflict(self, doc):
-        my_doc = self._get_doc(doc.doc_id)
-        self._prune_conflicts(doc, vectorclock.VectorClockRev(doc.rev))
-        self._add_conflict(doc.doc_id, my_doc.rev, my_doc.get_json())
-        doc.has_conflicts = True
-        self._put_and_update_indexes(my_doc, doc)
-
-
-#----------------------------------------------------------------------------
-# U1DB's TransactionLog, SyncLog, ConflictLog, and Index
-#----------------------------------------------------------------------------
-
-class SimpleList(object):
-    def __init__(self):
-        self._data = []
-
-    def _set_data(self, data):
-        self._data = data
-
-    def _get_data(self):
-        return self._data
-
-    data = property(
-        _get_data, _set_data, doc="List contents.")
-
-    def append(self, msg):
-        self._data.append(msg)
-
-    def reduce(self, func, initializer=None):
-        return reduce(func, self._data, initializer)
-
-    def map(self, func):
-        return map(func, self._get_data())
-
-    def filter(self, func):
-        return filter(func, self._get_data())
-
-
-class SimpleLog(SimpleList):
-
-    def _set_log(self, log):
-        self._data = log
-
-    def _get_log(self):
-        return self._data
-
-    log = property(
-        _get_log, _set_log, doc="Log contents.")
-
-
-class TransactionLog(SimpleLog):
-    """
-    An ordered list of (generation, doc_id, transaction_id) tuples.
-    """
-
-    def _set_log(self, log):
-        self._data = log
-
-    def _get_data(self, reverse=True):
-        return sorted(self._data, reverse=reverse)
-
-    _get_log = _get_data
-
-    log = property(
-        _get_log, _set_log, doc="Log contents.")
-
-    def get_generation(self):
-        """
-        Return the current generation.
+    def _init_u1db_data(self):
         """
-        gens = self.map(lambda x: x[0])
-        if not gens:
-            return 0
-        return max(gens)
-
-    def get_generation_info(self):
-        """
-        Return the current generation and transaction id.
-        """
-        if not self._get_log():
-            return(0, '')
-        info = self.map(lambda x: (x[0], x[2]))
-        return reduce(lambda x, y: x if (x[0] > y[0]) else y, info)
-
-    def get_trans_id_for_gen(self, gen):
-        """
-        Get the transaction id corresponding to a particular generation.
-        """
-        log = self.reduce(lambda x, y: y if y[0] == gen else x)
-        if log is None:
-            return None
-        return log[2]
-
-    def whats_changed(self, old_generation):
-        """
-        Return a list of documents that have changed since old_generation.
+        Initialize u1db configuration data on backend storage.
         """
-        results = self.filter(lambda x: x[0] > old_generation)
-        seen = set()
-        changes = []
-        newest_trans_id = ''
-        for generation, doc_id, trans_id in results:
-            if doc_id not in seen:
-                changes.append((doc_id, generation, trans_id))
-                seen.add(doc_id)
-        if changes:
-            cur_gen = changes[0][1]  # max generation
-            newest_trans_id = changes[0][2]
-            changes.reverse()
-        else:
-            results = self._get_log()
-            if not results:
-                cur_gen = 0
-                newest_trans_id = ''
-            else:
-                cur_gen, _, newest_trans_id = results[0]
-
-        return cur_gen, newest_trans_id, changes
-
-    def get_transaction_log(self):
-        """
-        Return only a list of (doc_id, transaction_id)
-        """
-        return map(lambda x: (x[1], x[2]),
-                   sorted(self._get_log(reverse=False)))
-
-
-class SyncLog(SimpleLog):
-    """
-    A list of (replica_id, generation, transaction_id) tuples.
-    """
-
-    def find_by_replica_uid(self, replica_uid):
-        if not self._get_log():
-            return ()
-        return self.reduce(lambda x, y: y if y[0] == replica_uid else x)
-
-    def get_replica_gen_and_trans_id(self, other_replica_uid):
-        """
-        Return the last known generation and transaction id for the other db
-        replica.
-        """
-        info = self.find_by_replica_uid(other_replica_uid)
-        if not info:
-            return (0, '')
-        return (info[1], info[2])
-
-    def set_replica_gen_and_trans_id(self, other_replica_uid,
-                                     other_generation, other_transaction_id):
-        """
-        Set the last-known generation and transaction id for the other
-        database replica.
-        """
-        self._set_log(self.filter(lambda x: x[0] != other_replica_uid))
-        self.append((other_replica_uid, other_generation,
-                     other_transaction_id))
-
-
-class ConflictLog(SimpleLog):
-    """
-    A list of (doc_id, my_doc_rev, my_content) tuples.
-    """
-
-    def __init__(self, factory):
-        super(ConflictLog, self).__init__()
-        self._factory = factory
-
-    def delete_conflicts(self, conflicts):
-        for conflict in conflicts:
-            self._set_log(self.filter(lambda x:
-                          x[0] != conflict[0] or x[1] != conflict[1]))
-
-    def get_conflicts(self, doc_id):
-        conflicts = self.filter(lambda x: x[0] == doc_id)
-        if not conflicts:
-            return []
-        return reversed(map(lambda x: self._factory(doc_id, x[1], x[2]),
-                            conflicts))
-
-    def has_conflicts(self, doc_id):
-        return bool(self.filter(lambda x: x[0] == doc_id))
+        NotImplementedError(self._init_u1db_data)