view hgext/convert/common.py @ 5832:2192ed187319

convert: add commandline.xargs(), use it in svn_sink class

Introduce commandline.xargs() to limit argument list with respect
to ARG_MAX bytes. If no ARG_MAX information available - use POSIX
required minimum of 4096 bytes.

Under Windows, while actual argument list length is limited to 32k,
shells impose their own limits on command line length, down to 2047 bytes
for cmd.exe under Windows NT/2k and about 2500 bytes for older 4nt.exe.
See http://support.microsoft.com/kb/830473 for details about cmd.exe
limitations.

Since ARG_MAX is limit for argument list and environment, we reserve half
of it and one byte for environment variables. This way with default ARG_MAX
(4096 bytes) we get value 2047 bytes which is OK for Windows too.

# common code for the convert extension
import base64, errno
import os
import cPickle as pickle
from mercurial import util
from mercurial.i18n import _

def encodeargs(args):
    def encodearg(s):
        lines = base64.encodestring(s)
        lines = [l.splitlines()[0] for l in lines]
        return ''.join(lines)

    s = pickle.dumps(args)
    return encodearg(s)

def decodeargs(s):
    s = base64.decodestring(s)
    return pickle.loads(s)

def checktool(exe, name=None):
    name = name or exe
    if not util.find_exe(exe):
        raise util.Abort('cannot find required "%s" tool' % name)

class NoRepo(Exception): pass

SKIPREV = 'SKIP'

class commit(object):
    def __init__(self, author, date, desc, parents, branch=None, rev=None,
                 extra={}):
        self.author = author
        self.date = date
        self.desc = desc
        self.parents = parents
        self.branch = branch
        self.rev = rev
        self.extra = extra

class converter_source(object):
    """Conversion source interface"""

    def __init__(self, ui, path=None, rev=None):
        """Initialize conversion source (or raise NoRepo("message")
        exception if path is not a valid repository)"""
        self.ui = ui
        self.path = path
        self.rev = rev

        self.encoding = 'utf-8'

    def before(self):
        pass

    def after(self):
        pass

    def setrevmap(self, revmap):
        """set the map of already-converted revisions"""
        pass

    def getheads(self):
        """Return a list of this repository's heads"""
        raise NotImplementedError()

    def getfile(self, name, rev):
        """Return file contents as a string"""
        raise NotImplementedError()

    def getmode(self, name, rev):
        """Return file mode, eg. '', 'x', or 'l'"""
        raise NotImplementedError()

    def getchanges(self, version):
        """Returns a tuple of (files, copies)
        Files is a sorted list of (filename, id) tuples for all files changed
        in version, where id is the source revision id of the file.

        copies is a dictionary of dest: source
        """
        raise NotImplementedError()

    def getcommit(self, version):
        """Return the commit object for version"""
        raise NotImplementedError()

    def gettags(self):
        """Return the tags as a dictionary of name: revision"""
        raise NotImplementedError()

    def recode(self, s, encoding=None):
        if not encoding:
            encoding = self.encoding or 'utf-8'

        if isinstance(s, unicode):
            return s.encode("utf-8")
        try:
            return s.decode(encoding).encode("utf-8")
        except:
            try:
                return s.decode("latin-1").encode("utf-8")
            except:
                return s.decode(encoding, "replace").encode("utf-8")

    def getchangedfiles(self, rev, i):
        """Return the files changed by rev compared to parent[i].

        i is an index selecting one of the parents of rev.  The return
        value should be the list of files that are different in rev and
        this parent.

        If rev has no parents, i is None.

        This function is only needed to support --filemap
        """
        raise NotImplementedError()

    def converted(self, rev, sinkrev):
        '''Notify the source that a revision has been converted.'''
        pass


class converter_sink(object):
    """Conversion sink (target) interface"""

    def __init__(self, ui, path):
        """Initialize conversion sink (or raise NoRepo("message")
        exception if path is not a valid repository)

        created is a list of paths to remove if a fatal error occurs
        later"""
        self.ui = ui
        self.path = path
        self.created = []

    def getheads(self):
        """Return a list of this repository's heads"""
        raise NotImplementedError()

    def revmapfile(self):
        """Path to a file that will contain lines
        source_rev_id sink_rev_id
        mapping equivalent revision identifiers for each system."""
        raise NotImplementedError()

    def authorfile(self):
        """Path to a file that will contain lines
        srcauthor=dstauthor
        mapping equivalent authors identifiers for each system."""
        return None

    def putfile(self, f, e, data):
        """Put file for next putcommit().
        f: path to file
        e: '', 'x', or 'l' (regular file, executable, or symlink)
        data: file contents"""
        raise NotImplementedError()

    def delfile(self, f):
        """Delete file for next putcommit().
        f: path to file"""
        raise NotImplementedError()

    def putcommit(self, files, parents, commit):
        """Create a revision with all changed files listed in 'files'
        and having listed parents. 'commit' is a commit object containing
        at a minimum the author, date, and message for this changeset.
        Called after putfile() and delfile() calls. Note that the sink
        repository is not told to update itself to a particular revision
        (or even what that revision would be) before it receives the
        file data."""
        raise NotImplementedError()

    def puttags(self, tags):
        """Put tags into sink.
        tags: {tagname: sink_rev_id, ...}"""
        raise NotImplementedError()

    def setbranch(self, branch, pbranch, parents):
        """Set the current branch name. Called before the first putfile
        on the branch.
        branch: branch name for subsequent commits
        pbranch: branch name of parent commit
        parents: destination revisions of parent"""
        pass

    def setfilemapmode(self, active):
        """Tell the destination that we're using a filemap

        Some converter_sources (svn in particular) can claim that a file
        was changed in a revision, even if there was no change.  This method
        tells the destination that we're using a filemap and that it should
        filter empty revisions.
        """
        pass

    def before(self):
        pass

    def after(self):
        pass


class commandline(object):
    def __init__(self, ui, command):
        self.ui = ui
        self.command = command

    def prerun(self):
        pass

    def postrun(self):
        pass

    def _cmdline(self, cmd, *args, **kwargs):
        cmdline = [self.command, cmd] + list(args)
        for k, v in kwargs.iteritems():
            if len(k) == 1:
                cmdline.append('-' + k)
            else:
                cmdline.append('--' + k.replace('_', '-'))
            try:
                if len(k) == 1:
                    cmdline.append('' + v)
                else:
                    cmdline[-1] += '=' + v
            except TypeError:
                pass
        cmdline = [util.shellquote(arg) for arg in cmdline]
        cmdline += ['<', util.nulldev]
        cmdline = ' '.join(cmdline)
        self.ui.debug(cmdline, '\n')
        return cmdline

    def _run(self, cmd, *args, **kwargs):
        cmdline = self._cmdline(cmd, *args, **kwargs)
        self.prerun()
        try:
            return util.popen(cmdline)
        finally:
            self.postrun()

    def run(self, cmd, *args, **kwargs):
        fp = self._run(cmd, *args, **kwargs)
        output = fp.read()
        self.ui.debug(output)
        return output, fp.close()

    def checkexit(self, status, output=''):
        if status:
            if output:
                self.ui.warn(_('%s error:\n') % self.command)
                self.ui.warn(output)
            msg = util.explain_exit(status)[0]
            raise util.Abort(_('%s %s') % (self.command, msg))

    def run0(self, cmd, *args, **kwargs):
        output, status = self.run(cmd, *args, **kwargs)
        self.checkexit(status, output)
        return output

    def getargmax(self):
        if '_argmax' in self.__dict__:
            return self._argmax

        # POSIX requires at least 4096 bytes for ARG_MAX
        self._argmax = 4096
        try:
            self._argmax = os.sysconf("SC_ARG_MAX")
        except:
            pass

        # Windows shells impose their own limits on command line length,
        # down to 2047 bytes for cmd.exe under Windows NT/2k and 2500 bytes
        # for older 4nt.exe. See http://support.microsoft.com/kb/830473 for
        # details about cmd.exe limitations.

        # Since ARG_MAX is for command line _and_ environment, lower our limit
        # (and make happy Windows shells while doing this).

        self._argmax = self._argmax/2 - 1
        return self._argmax

    def limit_arglist(self, arglist, cmd, *args, **kwargs):
        limit = self.getargmax() - len(self._cmdline(cmd, *args, **kwargs))
        bytes = 0
        fl = []
        for fn in arglist:
            b = len(fn) + 3
            if bytes + b < limit or len(fl) == 0:
                fl.append(fn)
                bytes += b
            else:
                yield fl
                fl = [fn]
                bytes = b
        if fl:
            yield fl

    def xargs(self, arglist, cmd, *args, **kwargs):
        for l in self.limit_arglist(arglist, cmd, *args, **kwargs):
            self.run0(cmd, *(list(args) + l), **kwargs)

class mapfile(dict):
    def __init__(self, ui, path):
        super(mapfile, self).__init__()
        self.ui = ui
        self.path = path
        self.fp = None
        self.order = []
        self._read()

    def _read(self):
        try:
            fp = open(self.path, 'r')
        except IOError, err:
            if err.errno != errno.ENOENT:
                raise
            return
        for line in fp:
            key, value = line[:-1].split(' ', 1)
            if key not in self:
                self.order.append(key)
            super(mapfile, self).__setitem__(key, value)
        fp.close()

    def __setitem__(self, key, value):
        if self.fp is None:
            try:
                self.fp = open(self.path, 'a')
            except IOError, err:
                raise util.Abort(_('could not open map file %r: %s') %
                                 (self.path, err.strerror))
        self.fp.write('%s %s\n' % (key, value))
        self.fp.flush()
        super(mapfile, self).__setitem__(key, value)

    def close(self):
        if self.fp:
            self.fp.close()
            self.fp = None