fix bad assumption about uniqueness of file versions
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Hash: SHA1
fix bad assumption about uniqueness of file versions
Mercurial had assumed that a given file hash could show up in only one
changeset, and thus that the mapping from file revision to changeset
was 1-to-1. But if two people perform the same edit with the same
parents, we can get an identical hash in different changesets.
So we've got to loosen up our uniqueness checks in addgroup and in
verify.
manifest hash: 5462003241e7d071ffa1741b87a59f646c9988ed
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# transaction.py - simple journalling scheme for mercurial
#
# This transaction scheme is intended to gracefully handle program
# errors and interruptions. More serious failures like system crashes
# can be recovered with an fsck-like tool. As the whole repository is
# effectively log-structured, this should amount to simply truncating
# anything that isn't referenced in the changelog.
#
# Copyright 2005 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.
import os
class transaction:
def __init__(self, opener, journal, after = None):
self.journal = None
# abort here if the journal already exists
if os.path.exists(journal):
raise "journal already exists - run hg recover"
self.opener = opener
self.after = after
self.entries = []
self.map = {}
self.journal = journal
self.file = open(self.journal, "w")
def __del__(self):
if self.entries: self.abort()
try: os.unlink(self.journal)
except: pass
def add(self, file, offset):
if file in self.map: return
self.entries.append((file, offset))
self.map[file] = 1
# add enough data to the journal to do the truncate
self.file.write("%s\0%d\n" % (file, offset))
self.file.flush()
def close(self):
self.file.close()
self.entries = []
if self.after:
os.rename(self.journal, self.after)
else:
os.unlink(self.journal)
def abort(self):
if not self.entries: return
print "transaction abort!"
for f, o in self.entries:
try:
self.opener(f, "a").truncate(o)
except:
print "failed to truncate", f
self.entries = []
print "rollback completed"
def rollback(opener, file):
for l in open(file).readlines():
f, o = l.split('\0')
opener(f, "a").truncate(int(o))
os.unlink(file)