Mercurial > hg-stable
view mercurial/transaction.py @ 8894:868670dbc237
extensions: improve the consistency of synopses
Trying as much as possible to consistently:
- use a present tense predicate followed by a direct object
- verb referring directly to the functionality provided
(ie. not "add command that does this" but simple "do that")
- keep simple and to the point, leaving details for the long help
(width is tight, possibly even more so for translations)
Thanks to timeless, Martin Geisler, Rafael Villar Burke, Dan Villiom
Podlaski Christiansen and others for the helpful suggestions.
author | Cédric Duval <cedricduval@free.fr> |
---|---|
date | Mon, 22 Jun 2009 15:48:08 +0200 |
parents | c8e81f557da7 |
children | 89ae64a4e2ec |
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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, incorporated herein by reference. from i18n import _ import os, errno import error 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: opener(f, 'a').truncate(o) except: report(_("failed to truncate %s\n") % f) raise else: try: fn = opener(f).name os.unlink(fn) except OSError, inst: if inst.errno != errno.ENOENT: raise os.unlink(journal) class transaction(object): def __init__(self, report, opener, journal, after=None, createmode=None): self.journal = None self.count = 1 self.report = report self.opener = opener self.after = after self.entries = [] self.map = {} self.journal = journal self._queue = [] self.file = open(self.journal, "w") if createmode is not None: os.chmod(self.journal, createmode & 0666) def __del__(self): if self.journal: if self.entries: self._abort() self.file.close() @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 return self def running(self): return self.count > 0 @active 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 @active def abort(self): self._abort() def _abort(self): self.count = 0 self.file.close() if not self.entries: return self.report(_("transaction abort!\n")) try: 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 = [] for l in open(file).readlines(): f, o = l.split('\0') entries.append((f, int(o), None)) _playback(file, report, opener, entries)