--- a/dbapi.py	Wed Mar 10 16:07:24 2010 +0100
+++ b/dbapi.py	Mon Mar 01 11:26:14 2010 +0100
@@ -57,6 +57,7 @@
     etypescls = cwvreg.VRegistry.REGISTRY_FACTORY['etypes']
     etypescls.etype_class = etypescls.orig_etype_class
 
+
 class ConnectionProperties(object):
     def __init__(self, cnxtype=None, lang=None, close=True, log=False):
         self.cnxtype = cnxtype or 'pyro'
@@ -546,16 +547,16 @@
         self._closed = 1
 
     def commit(self):
-        """Commit any pending transaction to the database. Note that if the
-        database supports an auto-commit feature, this must be initially off. An
-        interface method may be provided to turn it back on.
+        """Commit pending transaction for this connection to the repository.
 
-        Database modules that do not support transactions should implement this
-        method with void functionality.
+        may raises `Unauthorized` or `ValidationError` if we attempted to do
+        something we're not allowed to for security or integrity reason.
+
+        If the transaction is undoable, a transaction id will be returned.
         """
         if not self._closed is None:
             raise ProgrammingError('Connection is already closed')
-        self._repo.commit(self.sessionid)
+        return self._repo.commit(self.sessionid)
 
     def rollback(self):
         """This method is optional since not all databases provide transaction
@@ -582,6 +583,73 @@
             req = self.request()
         return self.cursor_class(self, self._repo, req=req)
 
+    # undo support ############################################################
+
+    def undoable_transactions(self, ueid=None, req=None, **actionfilters):
+        """Return a list of undoable transaction objects by the connection's
+        user, ordered by descendant transaction time.
+
+        Managers may filter according to user (eid) who has done the transaction
+        using the `ueid` argument. Others will only see their own transactions.
+
+        Additional filtering capabilities is provided by using the following
+        named arguments:
+
+        * `etype` to get only transactions creating/updating/deleting entities
+          of the given type
+
+        * `eid` to get only transactions applied to entity of the given eid
+
+        * `action` to get only transactions doing the given action (action in
+          'C', 'U', 'D', 'A', 'R'). If `etype`, action can only be 'C', 'U' or
+          'D'.
+
+        * `public`: when additional filtering is provided, their are by default
+          only searched in 'public' actions, unless a `public` argument is given
+          and set to false.
+        """
+        txinfos = self._repo.undoable_transactions(self.sessionid, ueid,
+                                                   **actionfilters)
+        if req is None:
+            req = self.request()
+        for txinfo in txinfos:
+            txinfo.req = req
+        return txinfos
+
+    def transaction_info(self, txuuid, req=None):
+        """Return transaction object for the given uid.
+
+        raise `NoSuchTransaction` if not found or if session's user is not
+        allowed (eg not in managers group and the transaction doesn't belong to
+        him).
+        """
+        txinfo = self._repo.transaction_info(self.sessionid, txuuid)
+        if req is None:
+            req = self.request()
+        txinfo.req = req
+        return txinfo
+
+    def transaction_actions(self, txuuid, public=True):
+        """Return an ordered list of action effectued during that transaction.
+
+        If public is true, return only 'public' actions, eg not ones triggered
+        under the cover by hooks, else return all actions.
+
+        raise `NoSuchTransaction` if the transaction is not found or if
+        session's user is not allowed (eg not in managers group and the
+        transaction doesn't belong to him).
+        """
+        return self._repo.transaction_actions(self.sessionid, txuuid, public)
+
+    def undo_transaction(self, txuuid):
+        """Undo the given transaction. Return potential restoration errors.
+
+        raise `NoSuchTransaction` if not found or if session's user is not
+        allowed (eg not in managers group and the transaction doesn't belong to
+        him).
+        """
+        return self._repo.undo_transaction(self.sessionid, txuuid)
+
 
 # cursor object ###############################################################