##// END OF EJS Templates
persistent-nodemap: introduce a test to highlight possible race...
persistent-nodemap: introduce a test to highlight possible race Weakness in the current file caching of the changelog means that a writer can end up using an outdated docket. This might result in "committed" persistent-nodemap data from a previous writer to be overwritten by a later writer. This break the strong "append only" assumption of the persistent nodemap and can result in confused reader. The race windows are quite narrow. See the test documentation for details. The issues is fixed in the next changeset. Differential Revision: https://phab.mercurial-scm.org/D11481

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revlogv0.py
147 lines | 3.8 KiB | text/x-python | PythonLexer
# revlogv0 - code related to revlog format "V0"
#
# Copyright 2005-2007 Olivia Mackall <olivia@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
from ..node import sha1nodeconstants
from .constants import (
INDEX_ENTRY_V0,
)
from ..i18n import _
from .. import (
error,
node,
pycompat,
revlogutils,
util,
)
from . import (
nodemap as nodemaputil,
)
def getoffset(q):
return int(q >> 16)
def gettype(q):
return int(q & 0xFFFF)
class revlogoldindex(list):
rust_ext_compat = 0
entry_size = INDEX_ENTRY_V0.size
null_item = revlogutils.entry(
data_offset=0,
data_compressed_length=0,
data_delta_base=node.nullrev,
link_rev=node.nullrev,
parent_rev_1=node.nullrev,
parent_rev_2=node.nullrev,
node_id=sha1nodeconstants.nullid,
)
@property
def nodemap(self):
msg = b"index.nodemap is deprecated, use index.[has_node|rev|get_rev]"
util.nouideprecwarn(msg, b'5.3', stacklevel=2)
return self._nodemap
@util.propertycache
def _nodemap(self):
nodemap = nodemaputil.NodeMap({sha1nodeconstants.nullid: node.nullrev})
for r in range(0, len(self)):
n = self[r][7]
nodemap[n] = r
return nodemap
def has_node(self, node):
"""return True if the node exist in the index"""
return node in self._nodemap
def rev(self, node):
"""return a revision for a node
If the node is unknown, raise a RevlogError"""
return self._nodemap[node]
def get_rev(self, node):
"""return a revision for a node
If the node is unknown, return None"""
return self._nodemap.get(node)
def append(self, tup):
self._nodemap[tup[7]] = len(self)
super(revlogoldindex, self).append(tup)
def __delitem__(self, i):
if not isinstance(i, slice) or not i.stop == -1 or i.step is not None:
raise ValueError(b"deleting slices only supports a:-1 with step 1")
for r in pycompat.xrange(i.start, len(self)):
del self._nodemap[self[r][7]]
super(revlogoldindex, self).__delitem__(i)
def clearcaches(self):
self.__dict__.pop('_nodemap', None)
def __getitem__(self, i):
if i == -1:
return self.null_item
return list.__getitem__(self, i)
def pack_header(self, header):
"""pack header information in binary"""
return b''
def entry_binary(self, rev):
"""return the raw binary string representing a revision"""
entry = self[rev]
if gettype(entry[0]):
raise error.RevlogError(
_(b'index entry flags need revlog version 1')
)
e2 = (
getoffset(entry[0]),
entry[1],
entry[3],
entry[4],
self[entry[5]][7],
self[entry[6]][7],
entry[7],
)
return INDEX_ENTRY_V0.pack(*e2)
def parse_index_v0(data, inline):
s = INDEX_ENTRY_V0.size
index = []
nodemap = nodemaputil.NodeMap({node.nullid: node.nullrev})
n = off = 0
l = len(data)
while off + s <= l:
cur = data[off : off + s]
off += s
e = INDEX_ENTRY_V0.unpack(cur)
# transform to revlogv1 format
e2 = revlogutils.entry(
data_offset=e[0],
data_compressed_length=e[1],
data_delta_base=e[2],
link_rev=e[3],
parent_rev_1=nodemap.get(e[4], node.nullrev),
parent_rev_2=nodemap.get(e[5], node.nullrev),
node_id=e[6],
)
index.append(e2)
nodemap[e[6]] = n
n += 1
index = revlogoldindex(index)
return index, None