Mercurial > hg
view mercurial/transaction.py @ 14333:31a5973fcf96
revlog: get rid of defversion
defversion was a property (later option) on the store opener, used to propagate
the changelog revlog format to the other revlogs, so they would be created with
the same format.
This required that the changelog instance was created before any other revlog;
an invariant that wasn't directly enforced (or documented) anywhere.
We now use the revlogv1 requirement instead, which is transfered to the store
opener options. If this option is missing, v0 revlogs are created.
author | Sune Foldager <cryo@cyanite.org> |
---|---|
date | Mon, 16 May 2011 12:44:34 +0200 |
parents | 19ad316e5be3 |
children | f366d4c2ff34 |
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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 version 2 or any later version. from i18n import _ import os, errno import error, util def active(func): def _active(self, *args, **kwds): if self.count == 0: raise error.Abort(_( 'cannot use transaction when it is already committed/aborted')) return func(self, *args, **kwds) return _active def _playback(journal, report, opener, entries, unlink=True): for f, o, ignore in entries: if o or not unlink: try: fp = opener(f, 'a') fp.truncate(o) fp.close() except IOError: report(_("failed to truncate %s\n") % f) raise else: try: fp = opener(f) fn = fp.name fp.close() util.unlink(fn) except (IOError, OSError), inst: if inst.errno != errno.ENOENT: raise util.unlink(journal) class transaction(object): def __init__(self, report, opener, journal, after=None, createmode=None): self.count = 1 self.usages = 1 self.report = report self.opener = opener self.after = after self.entries = [] self.map = {} self.journal = journal self._queue = [] self.file = util.posixfile(self.journal, "w") if createmode is not None: os.chmod(self.journal, createmode & 0666) def __del__(self): if self.journal: self._abort() @active def startgroup(self): self._queue.append([]) @active def endgroup(self): q = self._queue.pop() d = ''.join(['%s\0%d\n' % (x[0], x[1]) for x in q]) self.entries.extend(q) self.file.write(d) self.file.flush() @active def add(self, file, offset, data=None): if file in self.map: return if self._queue: self._queue[-1].append((file, offset, data)) 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() @active def find(self, file): if file in self.map: return self.entries[self.map[file]] return None @active def replace(self, file, offset, data=None): ''' replace can only replace already committed entries that are not pending in the queue ''' 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() @active def nest(self): self.count += 1 self.usages += 1 return self def release(self): if self.count > 0: self.usages -= 1 # if the transaction scopes are left without being closed, fail if self.count > 0 and self.usages == 0: self._abort() def running(self): return self.count > 0 @active def close(self): '''commit the transaction''' self.count -= 1 if self.count != 0: return self.file.close() self.entries = [] if self.after: self.after() if os.path.isfile(self.journal): util.unlink(self.journal) self.journal = None @active def abort(self): '''abort the transaction (generally called on error, or when the transaction is not explicitly committed before going out of scope)''' self._abort() def _abort(self): self.count = 0 self.usages = 0 self.file.close() try: if not self.entries: if self.journal: util.unlink(self.journal) return self.report(_("transaction abort!\n")) try: _playback(self.journal, self.report, self.opener, self.entries, False) self.report(_("rollback completed\n")) except: self.report(_("rollback failed - please run hg recover\n")) finally: self.journal = None def rollback(opener, file, report): entries = [] fp = util.posixfile(file) lines = fp.readlines() fp.close() for l in lines: f, o = l.split('\0') entries.append((f, int(o), None)) _playback(file, report, opener, entries)