Commit 8f9d1fc4 authored by Jeremy Hylton's avatar Jeremy Hylton

Move undoLog() before transactionalUndo().

It makes more sense in this order, because the comments in undoLog()
help to explain what transactionalUndo() is doing.
parent 663174eb
...@@ -115,7 +115,7 @@ ...@@ -115,7 +115,7 @@
# may have a back pointer to a version record or to a non-version # may have a back pointer to a version record or to a non-version
# record. # record.
# #
__version__='$Revision: 1.86 $'[11:-2] __version__='$Revision: 1.87 $'[11:-2]
import struct, time, os, string, base64, sys import struct, time, os, string, base64, sys
from struct import pack, unpack from struct import pack, unpack
...@@ -1035,6 +1035,86 @@ class FileStorage(BaseStorage.BaseStorage, ...@@ -1035,6 +1035,86 @@ class FileStorage(BaseStorage.BaseStorage,
raise UndoError('Some data were modified by a later transaction') raise UndoError('Some data were modified by a later transaction')
def undoLog(self, first=0, last=-20, filter=None):
if last < 0:
last = first - last + 1
self._lock_acquire()
try:
if self._packt is None:
raise UndoError(
'Undo is currently disabled for database maintenance.<p>')
pos = self._pos
# BAW: Why 39 please? This makes no sense (see also below).
if pos < 39:
return []
file=self._file
seek=file.seek
read=file.read
r = []
i = 0
while i < last and pos > 39:
self._file.seek(pos - 8)
pos = pos - U64(self._file.read(8)) - 8
self._file.seek(pos)
h = self._file.read(TRANS_HDR_LEN)
tid, tl, status, ul, dl, el = struct.unpack(">8s8scHHH", h)
if tid < self._packt:
break
if status != ' ':
continue
d = u = ''
if ul:
u = self._file.read(ul)
if dl:
d = self._file.read(dl)
e = {}
if el:
try:
e = loads(read(el))
except:
pass
# We now need an encoded id that isn't dependent on file
# position, because it will break after a pack, and in the
# face of replication, while the transaction and data records
# may be identical (as viewed from the storage interface),
# file positions may be meaningless across replicas.
#
# We'd love to just give the tid, but FS makes it expensive to
# go from tid to transaction record. :( However, if the txn
# has data records, then we can encode the oid of one of the
# objects affected by the txn. Then we can use the index to
# find the current revision of the object, follow a
# back-pointer to find its most-current txn, and then follow
# the txns back until we find a match. Seems like the best we
# can do w/o a persistent tid->filepos mapping.
#
# Note: if the txn has no data records, we're screwed. Punt
# on that for now.
#
# Note that we're still encoding the transaction position
# in the transaction ID in order to support non-transactional
# undo. This can be removed as soon as non-transactional
# undo is removed.
next = read(8)
# next is either the redundant txn length - 8, or an oid
if next == tl:
# There were no objects in this txn
id = tid + p64(pos)
else:
id = tid + p64(pos) + next
d = {'id': base64.encodestring(id).rstrip(),
'time': TimeStamp(tid).timeTime(),
'user_name': u,
'description': d}
d.update(e)
if filter is None or filter(d):
if i >= first:
r.append(d)
i += 1
return r
finally:
self._lock_release()
def transactionalUndo(self, transaction_id, transaction): def transactionalUndo(self, transaction_id, transaction):
"""Undo a transaction, given by transaction_id. """Undo a transaction, given by transaction_id.
...@@ -1162,86 +1242,6 @@ class FileStorage(BaseStorage.BaseStorage, ...@@ -1162,86 +1242,6 @@ class FileStorage(BaseStorage.BaseStorage,
finally: self._lock_release() finally: self._lock_release()
def undoLog(self, first=0, last=-20, filter=None):
if last < 0:
last = first - last + 1
self._lock_acquire()
try:
if self._packt is None:
raise UndoError(
'Undo is currently disabled for database maintenance.<p>')
pos = self._pos
# BAW: Why 39 please? This makes no sense (see also below).
if pos < 39:
return []
file=self._file
seek=file.seek
read=file.read
r = []
i = 0
while i < last and pos > 39:
self._file.seek(pos - 8)
pos = pos - U64(self._file.read(8)) - 8
self._file.seek(pos)
h = self._file.read(TRANS_HDR_LEN)
tid, tl, status, ul, dl, el = struct.unpack(">8s8scHHH", h)
if tid < self._packt:
break
if status != ' ':
continue
d = u = ''
if ul:
u = self._file.read(ul)
if dl:
d = self._file.read(dl)
e = {}
if el:
try:
e = loads(read(el))
except:
pass
# We now need an encoded id that isn't dependent on file
# position, because it will break after a pack, and in the
# face of replication, while the transaction and data records
# may be identical (as viewed from the storage interface),
# file positions may be meaningless across replicas.
#
# We'd love to just give the tid, but FS makes it expensive to
# go from tid to transaction record. :( However, if the txn
# has data records, then we can encode the oid of one of the
# objects affected by the txn. Then we can use the index to
# find the current revision of the object, follow a
# back-pointer to find its most-current txn, and then follow
# the txns back until we find a match. Seems like the best we
# can do w/o a persistent tid->filepos mapping.
#
# Note: if the txn has no data records, we're screwed. Punt
# on that for now.
#
# Note that we're still encoding the transaction position
# in the transaction ID in order to support non-transactional
# undo. This can be removed as soon as non-transactional
# undo is removed.
next = read(8)
# next is either the redundant txn length - 8, or an oid
if next == tl:
# There were no objects in this txn
id = tid + p64(pos)
else:
id = tid + p64(pos) + next
d = {'id': base64.encodestring(id).rstrip(),
'time': TimeStamp(tid).timeTime(),
'user_name': u,
'description': d}
d.update(e)
if filter is None or filter(d):
if i >= first:
r.append(d)
i += 1
return r
finally:
self._lock_release()
def versionEmpty(self, version): def versionEmpty(self, version):
if not version: if not version:
# The interface is silent on this case. I think that this should # The interface is silent on this case. I think that this should
......
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