transaction: backup file in a dedicated "namespace"
File backup may conflict with other "journal.*" file. We add a fixed part in the
backup name file to prevent it.
# filelog.py - file history class for mercurial
#
# Copyright 2005-2007 Matt Mackall <mpm@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.
import revlog
import re
_mdre = re.compile('\1\n')
def _parsemeta(text):
"""return (metadatadict, keylist, metadatasize)"""
# text can be buffer, so we can't use .startswith or .index
if text[:2] != '\1\n':
return None, None, None
s = _mdre.search(text, 2).start()
mtext = text[2:s]
meta = {}
keys = []
for l in mtext.splitlines():
k, v = l.split(": ", 1)
meta[k] = v
keys.append(k)
return meta, keys, (s + 2)
def _packmeta(meta, keys=None):
if not keys:
keys = sorted(meta.iterkeys())
return "".join("%s: %s\n" % (k, meta[k]) for k in keys)
class filelog(revlog.revlog):
def __init__(self, opener, path):
super(filelog, self).__init__(opener,
"/".join(("data", path + ".i")))
def read(self, node):
t = self.revision(node)
if not t.startswith('\1\n'):
return t
s = t.index('\1\n', 2)
return t[s + 2:]
def add(self, text, meta, transaction, link, p1=None, p2=None):
if meta or text.startswith('\1\n'):
text = "\1\n%s\1\n%s" % (_packmeta(meta), text)
return self.addrevision(text, transaction, link, p1, p2)
def renamed(self, node):
if self.parents(node)[0] != revlog.nullid:
return False
t = self.revision(node)
m = _parsemeta(t)[0]
if m and "copy" in m:
return (m["copy"], revlog.bin(m["copyrev"]))
return False
def size(self, rev):
"""return the size of a given revision"""
# for revisions with renames, we have to go the slow way
node = self.node(rev)
if self.renamed(node):
return len(self.read(node))
# XXX if self.read(node).startswith("\1\n"), this returns (size+4)
return super(filelog, self).size(rev)
def cmp(self, node, text):
"""compare text with a given file revision
returns True if text is different than what is stored.
"""
t = text
if text.startswith('\1\n'):
t = '\1\n\1\n' + text
samehashes = not super(filelog, self).cmp(node, t)
if samehashes:
return False
# renaming a file produces a different hash, even if the data
# remains unchanged. Check if it's the case (slow):
if self.renamed(node):
t2 = self.read(node)
return t2 != text
return True
def _file(self, f):
return filelog(self.opener, f)