From mercurial-bounces@selenic.com Thu Sep 1 07:01:32 2005 Return-Path: <mercurial-bounces@selenic.com> X-Original-To: bos@serpentine.com Delivered-To: bos@serpentine.com Received: from waste.org (waste.org [216.27.176.166]) by demesne.serpentine.com (Postfix) with ESMTP id 3616A20B571 for <bos@serpentine.com>; Thu, 1 Sep 2005 07:01:32 -0700 (PDT) Received: from waste.org (localhost [127.0.0.1]) by waste.org (8.13.4/8.13.4/Debian-3) with ESMTP id j81DxodQ028829; Thu, 1 Sep 2005 08:59:51 -0500 Received: from web32904.mail.mud.yahoo.com (web32904.mail.mud.yahoo.com [68.142.206.51]) by waste.org (8.13.4/8.13.4/Debian-3) with SMTP id j81DxnNA028824 for <mercurial@selenic.com>; Thu, 1 Sep 2005 08:59:49 -0500 Received: (qmail 25859 invoked by uid 60001); 1 Sep 2005 13:59:17 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Message-ID:Received:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=O6sELrlCknW3M/gKVqijWs82e/CbDEum1sEitcuLKXaP9dHU175PszOqMgcSKykMY+BVXtcH3NeaXLM3FyBmqNkoPAvesezyFbgQsHSM1S028oOexybCKMvtGQJmz66hzd1fDb0QoPj1gCcGU2VDevQaOesSmo1xF9jJwy2LlLE= ; Message-ID: <20050901135917.25856.qmail@web32904.mail.mud.yahoo.com> Received: from [60.48.222.94] by web32904.mail.mud.yahoo.com via HTTP; Thu, 01 Sep 2005 06:59:17 PDT Date: Thu, 1 Sep 2005 06:59:17 -0700 (PDT) From: TK Soh <teekaysoh@yahoo.com> To: mercurial@selenic.com In-Reply-To: <20050828075808.GO27787@waste.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 X-Virus-Scanned: by amavisd-new Subject: Re: add -p to hg tip X-BeenThere: mercurial@selenic.com X-Mailman-Version: 2.1.5 Precedence: list List-Id: mercurial.selenic.com List-Unsubscribe: <http://selenic.com/mailman/listinfo/mercurial>, <mailto:mercurial-request@selenic.com?subject=unsubscribe> List-Archive: <http://www.selenic.com/pipermail/mercurial> List-Post: <mailto:mercurial@selenic.com> List-Help: <mailto:mercurial-request@selenic.com?subject=help> List-Subscribe: <http://selenic.com/mailman/listinfo/mercurial>, <mailto:mercurial-request@selenic.com?subject=subscribe> Sender: mercurial-bounces@selenic.com Errors-To: mercurial-bounces@selenic.com X-Spam-Checker-Version: SpamAssassin 3.0.4 (2005-06-05) on demesne.serpentine.com X-Spam-Level: X-Spam-Status: No, score=-1.6 required=5.0 tests=AWL,BAYES_00 autolearn=ham version=3.0.4 X-Evolution-Source: imap://bos@www.serpentine.com/ Content-Transfer-Encoding: 8bit

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# transaction.py - simple journalling scheme for mercurial

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#

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# This transaction scheme is intended to gracefully handle program

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# errors and interruptions. More serious failures like system crashes

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# can be recovered with an fsck-like tool. As the whole repository is

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# effectively log-structured, this should amount to simply truncating

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# anything that isn't referenced in the changelog.

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#

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# Copyright 2005 Matt Mackall <mpm@selenic.com>

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#

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# This software may be used and distributed according to the terms

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# of the GNU General Public License, incorporated herein by reference.

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import os

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import util

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class transaction:

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    def __init__(self, report, opener, journal, after=None):

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        self.journal = None

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        # abort here if the journal already exists

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        if os.path.exists(journal):

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            raise AssertionError("journal already exists - run hg recover")

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        self.report = report

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        self.opener = opener

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        self.after = after

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        self.entries = []

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        self.map = {}

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        self.journal = journal

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        self.file = open(self.journal, "w")

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    def __del__(self):

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        if self.journal:

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            if self.entries: self.abort()

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            self.file.close()

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            try: os.unlink(self.journal)

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            except: pass

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    def add(self, file, offset):

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        if file in self.map: return

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        self.entries.append((file, offset))

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        self.map[file] = 1

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        # add enough data to the journal to do the truncate

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        self.file.write("%s\0%d\n" % (file, offset))

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        self.file.flush()

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    def close(self):

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        self.file.close()

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        self.entries = []

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        if self.after:

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            self.after()

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        else:

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            os.unlink(self.journal)

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        self.journal = None

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    def abort(self):

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        if not self.entries: return

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        self.report("transaction abort!\n")

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        for f, o in self.entries:

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            try:

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                self.opener(f, "a").truncate(o)

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            except:

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                self.report("failed to truncate %s\n" % f)

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        self.entries = []

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        self.report("rollback completed\n")

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def rollback(opener, file):

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    for l in open(file).readlines():

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        f, o = l.split('\0')

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        opener(f, "a").truncate(int(o))

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    os.unlink(file)

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