hgext/convert/darcs.py

streamclone: clear caches after writing changes into files for visibility

Before this patch, streamclone-ed changes are invisible via @filecache
properties to in-process procedures before closing transaction
(e.g. pretxnclose python hook), if corresponded property is cached
before consumev1(). Strictly speaking, caching should occur inside
(store) lock for transaction.

repo.invalidate() after closing transaction is too late to force
@filecache properties to be reloaded from changed files at next
access.

For visibility of streamclone-ed changes to in-process procedures
before closing transaction, this patch clears caches just after
writing changes into files.

BTW, regardless of changing in this patch, clearing cached properties
in consumev1() causes inconsistency, if (1) transaction is started and
(2) any @filecache property is changed before consumev1().

This patch also adds the comment to fix this (potential) inconsistency
in the future.

# darcs.py - darcs support for the convert extension
#
#  Copyright 2007-2009 Matt Mackall <[e-mail]> and others
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import

import errno
import os
import re
import shutil
import tempfile
from mercurial.i18n import _
from mercurial import (
    error,
    util,
)
from . import common
NoRepo = common.NoRepo

# The naming drift of ElementTree is fun!

try:
    import xml.etree.cElementTree.ElementTree as ElementTree
    import xml.etree.cElementTree.XMLParser as XMLParser
except ImportError:
    try:
        import xml.etree.ElementTree.ElementTree as ElementTree
        import xml.etree.ElementTree.XMLParser as XMLParser
    except ImportError:
        try:
            import elementtree.cElementTree.ElementTree as ElementTree
            import elementtree.cElementTree.XMLParser as XMLParser
        except ImportError:
            try:
                import elementtree.ElementTree.ElementTree as ElementTree
                import elementtree.ElementTree.XMLParser  as XMLParser
            except ImportError:
                pass

class darcs_source(common.converter_source, common.commandline):
    def __init__(self, ui, path, revs=None):
        common.converter_source.__init__(self, ui, path, revs=revs)
        common.commandline.__init__(self, ui, 'darcs')

        # check for _darcs, ElementTree so that we can easily skip
        # test-convert-darcs if ElementTree is not around
        if not os.path.exists(os.path.join(path, '_darcs')):
            raise NoRepo(_("%s does not look like a darcs repository") % path)

        common.checktool('darcs')
        version = self.run0('--version').splitlines()[0].strip()
        if version < '2.1':
            raise error.Abort(_('darcs version 2.1 or newer needed (found %r)')
                              % version)

        if "ElementTree" not in globals():
            raise error.Abort(_("Python ElementTree module is not available"))

        self.path = os.path.realpath(path)

        self.lastrev = None
        self.changes = {}
        self.parents = {}
        self.tags = {}

        # Check darcs repository format
        format = self.format()
        if format:
            if format in ('darcs-1.0', 'hashed'):
                raise NoRepo(_("%s repository format is unsupported, "
                               "please upgrade") % format)
        else:
            self.ui.warn(_('failed to detect repository format!'))

    def before(self):
        self.tmppath = tempfile.mkdtemp(
            prefix='convert-' + os.path.basename(self.path) + '-')
        output, status = self.run('init', repodir=self.tmppath)
        self.checkexit(status)

        tree = self.xml('changes', xml_output=True, summary=True,
                        repodir=self.path)
        tagname = None
        child = None
        for elt in tree.findall('patch'):
            node = elt.get('hash')
            name = elt.findtext('name', '')
            if name.startswith('TAG '):
                tagname = name[4:].strip()
            elif tagname is not None:
                self.tags[tagname] = node
                tagname = None
            self.changes[node] = elt
            self.parents[child] = [node]
            child = node
        self.parents[child] = []

    def after(self):
        self.ui.debug('cleaning up %s\n' % self.tmppath)
        shutil.rmtree(self.tmppath, ignore_errors=True)

    def recode(self, s, encoding=None):
        if isinstance(s, unicode):
            # XMLParser returns unicode objects for anything it can't
            # encode into ASCII. We convert them back to str to get
            # recode's normal conversion behavior.
            s = s.encode('latin-1')
        return super(darcs_source, self).recode(s, encoding)

    def xml(self, cmd, **kwargs):
        # NOTE: darcs is currently encoding agnostic and will print
        # patch metadata byte-for-byte, even in the XML changelog.
        etree = ElementTree()
        # While we are decoding the XML as latin-1 to be as liberal as
        # possible, etree will still raise an exception if any
        # non-printable characters are in the XML changelog.
        parser = XMLParser(encoding='latin-1')
        p = self._run(cmd, **kwargs)
        etree.parse(p.stdout, parser=parser)
        p.wait()
        self.checkexit(p.returncode)
        return etree.getroot()

    def format(self):
        output, status = self.run('show', 'repo', no_files=True,
                                  repodir=self.path)
        self.checkexit(status)
        m = re.search(r'^\s*Format:\s*(.*)$', output, re.MULTILINE)
        if not m:
            return None
        return ','.join(sorted(f.strip() for f in m.group(1).split(',')))

    def manifest(self):
        man = []
        output, status = self.run('show', 'files', no_directories=True,
                                  repodir=self.tmppath)
        self.checkexit(status)
        for line in output.split('\n'):
            path = line[2:]
            if path:
                man.append(path)
        return man

    def getheads(self):
        return self.parents[None]

    def getcommit(self, rev):
        elt = self.changes[rev]
        date = util.strdate(elt.get('local_date'), '%a %b %d %H:%M:%S %Z %Y')
        desc = elt.findtext('name') + '\n' + elt.findtext('comment', '')
        # etree can return unicode objects for name, comment, and author,
        # so recode() is used to ensure str objects are emitted.
        return common.commit(author=self.recode(elt.get('author')),
                             date=util.datestr(date, '%Y-%m-%d %H:%M:%S %1%2'),
                             desc=self.recode(desc).strip(),
                             parents=self.parents[rev])

    def pull(self, rev):
        output, status = self.run('pull', self.path, all=True,
                                  match='hash %s' % rev,
                                  no_test=True, no_posthook=True,
                                  external_merge='/bin/false',
                                  repodir=self.tmppath)
        if status:
            if output.find('We have conflicts in') == -1:
                self.checkexit(status, output)
            output, status = self.run('revert', all=True, repodir=self.tmppath)
            self.checkexit(status, output)

    def getchanges(self, rev, full):
        if full:
            raise error.Abort(_("convert from darcs does not support --full"))
        copies = {}
        changes = []
        man = None
        for elt in self.changes[rev].find('summary').getchildren():
            if elt.tag in ('add_directory', 'remove_directory'):
                continue
            if elt.tag == 'move':
                if man is None:
                    man = self.manifest()
                source, dest = elt.get('from'), elt.get('to')
                if source in man:
                    # File move
                    changes.append((source, rev))
                    changes.append((dest, rev))
                    copies[dest] = source
                else:
                    # Directory move, deduce file moves from manifest
                    source = source + '/'
                    for f in man:
                        if not f.startswith(source):
                            continue
                        fdest = dest + '/' + f[len(source):]
                        changes.append((f, rev))
                        changes.append((fdest, rev))
                        copies[fdest] = f
            else:
                changes.append((elt.text.strip(), rev))
        self.pull(rev)
        self.lastrev = rev
        return sorted(changes), copies, set()

    def getfile(self, name, rev):
        if rev != self.lastrev:
            raise error.Abort(_('internal calling inconsistency'))
        path = os.path.join(self.tmppath, name)
        try:
            data = util.readfile(path)
            mode = os.lstat(path).st_mode
        except IOError as inst:
            if inst.errno == errno.ENOENT:
                return None, None
            raise
        mode = (mode & 0o111) and 'x' or ''
        return data, mode

    def gettags(self):
        return self.tags