Mercurial > hg
view mercurial/transaction.py @ 2434:a2df85adface
http server: support persistent connections.
only "hg serve" affected yet. http server running cgi script will not
use persistent connections. support for fastcgi will help that.
clients that support keepalive can use one tcp connection for all
commands during clone and pull. this makes latency of binary search
during pull much lower over wan.
if server does not know content-length, it will force connection to
close at end. right fix is to use chunked transfer-encoding but this is
easier and does not hurt performance. only command that is affected is
"changegroup" which is always last command during a pull.
author | Vadim Gelfer <vadim.gelfer@gmail.com> |
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date | Thu, 15 Jun 2006 12:55:58 -0700 |
parents | d66278012853 |
children | fe1689273f84 |
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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 from i18n import gettext as _ class transaction(object): def __init__(self, report, opener, journal, after=None): self.journal = None # abort here if the journal already exists if os.path.exists(journal): raise AssertionError(_("journal already exists - run hg recover")) self.count = 1 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, data=None): if file in self.map: 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() def find(self, file): if file in self.map: return self.entries[self.map[file]] return None def replace(self, file, offset, data=None): 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() def nest(self): self.count += 1 return self def running(self): return self.count > 0 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 def abort(self): if not self.entries: return self.report(_("transaction abort!\n")) for f, o, ignore 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): files = {} for l in open(file).readlines(): f, o = l.split('\0') files[f] = o for f in files: o = files[f] opener(f, "a").truncate(int(o)) os.unlink(file)