mercurial/transaction.py
author Alexis S. L. Carvalho <alexis@cecm.usp.br>
Mon, 16 Apr 2007 20:17:39 -0300
changeset 4359 2e3c54fb79a3
parent 3893 6b4127c7d52a
permissions -rw-r--r--
actually port simplemerge to hg - use bdiff instead of patiencediff; this is a larger change, since bdiff works on 2 multi-line strings, while patiencediff works on 2 lists; - rename the main class from Merge3 to Merge3Text and add a Merge3 class that derives from Merge3Text. This new Merge3 class has the same interface from the original class, so that the tests still work; - Merge3 uses util.binary to detect binary data and raises util.Abort instead of a specific exception; - don't use the @decorator syntax, to keep python2.3 compatibility; - the test uses unittest, which likes to print how long it took to run. This obviously doesn't play too well with hg's test suite, so we override time.time to fool unittest; - one test has a different (but still valid) output because of the different diff algorithm used; - the TestCase class used by bzr has some extras to help debugging. test-merge3.py used 2 of them: - log method to log some data - assertEqualDiff method to ease viewing diffs of diffs We add a dummy log method and use regular assertEquals instead of assertEqualDiff. - make simplemerge executable and add "#!/usr/bin/env python" header

# 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, incorporated herein by reference.

from i18n import _
import os

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)