1 files changed, 125 insertions, 0 deletions
diff --git a/client/src/leap/soledad/client/sync.py b/client/src/leap/soledad/client/sync.py
new file mode 100644
index 00000000..56e63416
--- /dev/null
+++ b/client/src/leap/soledad/client/sync.py
@@ -0,0 +1,125 @@
+# -*- coding: utf-8 -*-
+# sync.py
+# Copyright (C) 2014 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+"""
+Sync infrastructure that can be interrupted and recovered.
+"""
+
+import json
+
+
+from u1db import errors
+from u1db.sync import Synchronizer as U1DBSynchronizer
+
+
+class Synchronizer(U1DBSynchronizer):
+    """
+    Collect the state around synchronizing 2 U1DB replicas.
+
+    Modified to allow for interrupting the synchronization process.
+    """
+
+    def stop(self):
+        """
+        Stop the current sync in progress.
+        """
+        self.sync_target.stop()
+
+    def sync(self, autocreate=False):
+        """
+        Synchronize documents between source and target.
+
+        :param autocreate: Whether the target replica should be created or not.
+        :type autocreate: bool
+        """
+        sync_target = self.sync_target
+
+        # get target identifier, its current generation,
+        # and its last-seen database generation for this source
+        ensure_callback = None
+        try:
+            (self.target_replica_uid, target_gen, target_trans_id,
+             target_my_gen, target_my_trans_id) = \
+                sync_target.get_sync_info(self.source._replica_uid)
+        except errors.DatabaseDoesNotExist:
+            if not autocreate:
+                raise
+            # will try to ask sync_exchange() to create the db
+            self.target_replica_uid = None
+            target_gen, target_trans_id = (0, '')
+            target_my_gen, target_my_trans_id = (0, '')
+
+        # make sure we'll have access to target replica uid once it exists
+        if self.target_replica_uid is None:
+
+            def ensure_callback(replica_uid):
+                self.target_replica_uid = replica_uid
+
+        # make sure we're not syncing one replica with itself
+        if self.target_replica_uid == self.source._replica_uid:
+            raise errors.InvalidReplicaUID
+
+        # validate the info the target has about the source replica
+        self.source.validate_gen_and_trans_id(
+            target_my_gen, target_my_trans_id)
+
+        # what's changed since that generation and this current gen
+        my_gen, _, changes = self.source.whats_changed(target_my_gen)
+
+        # get source last-seen database generation for the target
+        if self.target_replica_uid is None:
+            target_last_known_gen, target_last_known_trans_id = 0, ''
+        else:
+            target_last_known_gen, target_last_known_trans_id = \
+                self.source._get_replica_gen_and_trans_id(
+                    self.target_replica_uid)
+
+        # validate transaction ids
+        if not changes and target_last_known_gen == target_gen:
+            if target_trans_id != target_last_known_trans_id:
+                raise errors.InvalidTransactionId
+            return my_gen
+
+        # prepare to send all the changed docs
+        changed_doc_ids = [doc_id for doc_id, _, _ in changes]
+        docs_to_send = self.source.get_docs(
+            changed_doc_ids, check_for_conflicts=False, include_deleted=True)
+        docs_by_generation = []
+        idx = 0
+        for doc in docs_to_send:
+            _, gen, trans = changes[idx]
+            docs_by_generation.append((doc, gen, trans))
+            idx += 1
+
+        # exchange documents and try to insert the returned ones with
+        # the target, return target synced-up-to gen.
+        #
+        # The sync_exchange method may be interrupted, in which case it will
+        # return a tuple of Nones.
+        new_gen, new_trans_id = sync_target.sync_exchange(
+            docs_by_generation, self.source._replica_uid,
+            target_last_known_gen, target_last_known_trans_id,
+            self._insert_doc_from_target, ensure_callback=ensure_callback)
+
+        # record target synced-up-to generation including applying what we sent
+        self.source._set_replica_gen_and_trans_id(
+            self.target_replica_uid, new_gen, new_trans_id)
+        # if gapless record current reached generation with target
+        self._record_sync_info_with_the_target(my_gen)
+
+        return my_gen