Mercurial > hg > mercurial-crew-with-dirclash
view mercurial/transaction.py @ 3755:05120e210c65
Use unsigned version format.
This way can use one additional bit, and when encountering invalid revlogs
with the first bit set don't produce python warnings or strange error messages.
author | Thomas Arendsen Hein <thomas@intevation.de> |
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date | Fri, 01 Dec 2006 23:27:53 +0100 |
parents | 345bac2bc4ec |
children | abaee83ce0a6 |
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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, 2006 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. from demandload import demandload from i18n import gettext as _ demandload(globals(), 'os') class transaction(object): def __init__(self, report, opener, journal, after=None): self.journal = None # abort here if the journal already exists if os.path.exists(journal): raise AssertionError(_("journal already exists - run hg recover")) self.count = 1 self.report = report self.opener = opener self.after = after self.entries = [] self.map = {} self.journal = journal self.file = open(self.journal, "w") def __del__(self): if self.journal: if self.entries: self.abort() self.file.close() try: os.unlink(self.journal) except: pass def add(self, file, offset, data=None): if file in self.map: return self.entries.append((file, offset, data)) self.map[file] = len(self.entries) - 1 # add enough data to the journal to do the truncate self.file.write("%s\0%d\n" % (file, offset)) self.file.flush() def find(self, file): if file in self.map: return self.entries[self.map[file]] return None def replace(self, file, offset, data=None): if file not in self.map: raise KeyError(file) index = self.map[file] self.entries[index] = (file, offset, data) self.file.write("%s\0%d\n" % (file, offset)) self.file.flush() def nest(self): self.count += 1 return self def running(self): return self.count > 0 def close(self): self.count -= 1 if self.count != 0: return self.file.close() self.entries = [] if self.after: self.after() else: os.unlink(self.journal) self.journal = None def abort(self): if not self.entries: return self.report(_("transaction abort!\n")) for f, o, ignore in self.entries: try: self.opener(f, "a").truncate(o) except: self.report(_("failed to truncate %s\n") % f) self.entries = [] self.report(_("rollback completed\n")) def rollback(opener, file): files = {} for l in open(file).readlines(): f, o = l.split('\0') files[f] = o for f in files: o = files[f] opener(f, "a").truncate(int(o)) os.unlink(file)