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-rw-r--r--__init__.py131
1 files changed, 131 insertions, 0 deletions
diff --git a/__init__.py b/__init__.py
index b7082e53..7f742a89 100644
--- a/__init__.py
+++ b/__init__.py
@@ -41,3 +41,134 @@ class GPGWrapper():
def import_keys(self, data):
return self.gpg.import_keys(data)
+
+
+#----------------------------------------------------------------------------
+# u1db Transaction and Sync logs as JSON structures.
+#----------------------------------------------------------------------------
+
+class SimpleLog(object):
+ def __init__(self):
+ self._log = []
+
+ def _set_log(self, log):
+ self._log = log
+
+ def _get_log(self):
+ return self._log
+
+ log = property(
+ _get_log, _set_log, doc="Log contents.")
+
+ def append(self, msg):
+ self._log.append(msg)
+
+ def reduce(self, func, initializer=None):
+ return reduce(func, self.log, initializer)
+
+ def map(self, func):
+ return map(func, self.log)
+
+ def filter(self, func):
+ return filter(func, self.log)
+
+
+class TransactionLog(SimpleLog):
+ """
+ An ordered list of (generation, doc_id, transaction_id) tuples.
+ """
+
+ def _set_log(self, log):
+ self._log = log
+
+ def _get_log(self):
+ return sorted(self._log, reverse=True)
+
+ log = property(
+ _get_log, _set_log, doc="Log contents.")
+
+ def get_generation(self):
+ """
+ Return the current generation.
+ """
+ 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._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.
+ """
+ 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.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
+
+
+
+class SyncLog(SimpleLog):
+ """
+ A list of (replica_id, generation, transaction_id) tuples.
+ """
+
+ def find_by_replica_uid(self, replica_uid):
+ if not self.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.log = self.filter(lambda x: x[0] != other_replica_uid)
+ self.append((other_replica_uid, other_generation,
+ other_transaction_id))
+