diff options
Diffstat (limited to 'websdk/mercurial/transaction.py')
| -rw-r--r--[l---------] | websdk/mercurial/transaction.py | 184 |
1 files changed, 183 insertions, 1 deletions
diff --git a/websdk/mercurial/transaction.py b/websdk/mercurial/transaction.py index 72e2f41..d197295 120000..100644 --- a/websdk/mercurial/transaction.py +++ b/websdk/mercurial/transaction.py @@ -1 +1,183 @@ -/usr/share/pyshared/mercurial/transaction.py
\ No newline at end of file +# 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) |