Mercurial > hg
view mercurial/transaction.py @ 17013:c8eda7bbdcab
strip: incrementally update the branchheads cache after a strip
This function augments strip to incrementally update the branchheads cache
rather than recompute it from scratch. This speeds up the performance of strip
and rebase on repos with long history. The performance optimization only
happens if the revisions stripped are all on the same branch and the parents of
the stripped revisions are also on that same branch.
This adds a few test cases, particularly one that reproduces the extra heads
that mpm observed.
author | Joshua Redstone <joshua.redstone@fb.com> |
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date | Fri, 18 May 2012 12:45:47 -0700 |
parents | f366d4c2ff34 |
children | e7cfe3587ea4 |
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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 Exception: 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)