Mercurial > hg
view mercurial/transaction.py @ 209:63af1db35611
Beginning of new command parsing interface
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Beginning of new command parsing interface
This adds commands.py, with a primary interface dispatch(args)
Dispatch searches a table of known commands, handles switches, sets up
a repo object if appropriate, and dispatches the command.
It also handles KeyboardInterrupt and can handle similar exceptions in
the future.
If the command is unknown, it falls through to the current command handler.
Commands currently handled by the new scheme: help, init, and annotate
manifest hash: 134cd032c880985e3f92f82efb8b629dd862ba4c
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author | mpm@selenic.com |
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date | Wed, 01 Jun 2005 00:25:42 -0800 |
parents | 5dcbe4d9a30c |
children | 43b8da7420a9 688d03d6997a |
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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 class transaction: def __init__(self, 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.opener = opener self.after = after self.entries = [] self.map = {} self.journal = journal self.file = open(self.journal, "w") def __del__(self): if self.entries: self.abort() 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: os.rename(self.journal, self.after) else: os.unlink(self.journal) def abort(self): if not self.entries: return print "transaction abort!" for f, o in self.entries: try: self.opener(f, "a").truncate(o) except: print "failed to truncate", f self.entries = [] print "rollback completed" def rollback(opener, file): for l in open(file).readlines(): f, o = l.split('\0') opener(f, "a").truncate(int(o)) os.unlink(file)