Mercurial > hg > mercurial-crew-with-dirclash
view mercurial/transaction.py @ 596:9a8daeff0ffa
A bunch of parsing/help updates
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A bunch of parsing/help updates
more explanation of how to get non-basic commands
shorten names of debug functions and add docstrings
add undo long docstring
promote anotate, export, and revert
make the global opts array global
refactor parsing
kill two unused arguments to fancyopts
update test-help
manifest hash: 459ae2273aaf54f71b4576677a681dc53ab2908c
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author | mpm@selenic.com |
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date | Sun, 03 Jul 2005 11:47:45 -0800 |
parents | df8a5a0098d4 |
children | 46a8dd3145cc 445970ccf57a |
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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 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. import os import util class transaction: def __init__(self, report, opener, journal, after = None): self.journal = None # abort here if the journal already exists if os.path.exists(journal): raise "journal already exists - run hg recover" 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): if file in self.map: return self.entries.append((file, offset)) self.map[file] = 1 # add enough data to the journal to do the truncate self.file.write("%s\0%d\n" % (file, offset)) self.file.flush() def close(self): self.file.close() self.entries = [] if self.after: util.rename(self.journal, 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 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): for l in open(file).readlines(): f, o = l.split('\0') opener(f, "a").truncate(int(o)) os.unlink(file)