hgext/convert/common.py

git: skeleton of a new extension to _directly_ operate on git repos

This is based in part of work I did years ago in hgit, but it's mostly
new code since I'm using pygit2 instead of dulwich and the hg storage
interfaces have improved. Some cleanup of old hgit code by Pulkit,
which I greatly appreciate.

test-git-interop.t does not cover a whole lot of cases, but it
passes. It includes status, diff, making a new commit, and `hg annotate`
working on the git repository.

This is _not_ (yet) production quality code: this is an
experiment. Known technical debt lurking in this implementation:

 * Writing bookmarks just totally ignores transactions.
 * The way progress is threaded down into the gitstore is awful.
 * Ideally we'd find a way to incrementally reindex DAGs. I'm not sure
   how to do that efficiently, so we might need a "known only fast-forwards"
   mode on the DAG indexer for use on `hg commit` and friends.
 * We don't even _try_ to do anything reasonable for `hg pull` or `hg push`.
 * Mercurial need an interface for the changelog type.

Tests currently require git 2.24 as far as I'm aware: `git status` has
some changed output that I didn't try and handle in a compatible way.

This patch has produced some interesting cleanups, most recently on
the manifest type. I expect continuing down this road will produce
other meritorious cleanups throughout our code.

Differential Revision: https://phab.mercurial-scm.org/D6734

# common.py - common code for the convert extension
#
#  Copyright 2005-2009 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 base64
import datetime
import errno
import os
import re
import shlex
import subprocess

from mercurial.i18n import _
from mercurial.pycompat import open
from mercurial import (
    encoding,
    error,
    phases,
    pycompat,
    util,
)
from mercurial.utils import procutil

pickle = util.pickle
propertycache = util.propertycache


def _encodeornone(d):
    if d is None:
        return
    return d.encode('latin1')


class _shlexpy3proxy(object):
    def __init__(self, l):
        self._l = l

    def __iter__(self):
        return (_encodeornone(v) for v in self._l)

    def get_token(self):
        return _encodeornone(self._l.get_token())

    @property
    def infile(self):
        return self._l.infile or b'<unknown>'

    @property
    def lineno(self):
        return self._l.lineno


def shlexer(data=None, filepath=None, wordchars=None, whitespace=None):
    if data is None:
        if pycompat.ispy3:
            data = open(filepath, b'r', encoding='latin1')
        else:
            data = open(filepath, b'r')
    else:
        if filepath is not None:
            raise error.ProgrammingError(
                b'shlexer only accepts data or filepath, not both'
            )
        if pycompat.ispy3:
            data = data.decode('latin1')
    l = shlex.shlex(data, infile=filepath, posix=True)
    if whitespace is not None:
        l.whitespace_split = True
        if pycompat.ispy3:
            l.whitespace += whitespace.decode('latin1')
        else:
            l.whitespace += whitespace
    if wordchars is not None:
        if pycompat.ispy3:
            l.wordchars += wordchars.decode('latin1')
        else:
            l.wordchars += wordchars
    if pycompat.ispy3:
        return _shlexpy3proxy(l)
    return l


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

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


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


class MissingTool(Exception):
    pass


def checktool(exe, name=None, abort=True):
    name = name or exe
    if not procutil.findexe(exe):
        if abort:
            exc = error.Abort
        else:
            exc = MissingTool
        raise exc(_(b'cannot find required "%s" tool') % name)


class NoRepo(Exception):
    pass


SKIPREV = b'SKIP'


class commit(object):
    def __init__(
        self,
        author,
        date,
        desc,
        parents,
        branch=None,
        rev=None,
        extra=None,
        sortkey=None,
        saverev=True,
        phase=phases.draft,
        optparents=None,
        ctx=None,
    ):
        self.author = author or b'unknown'
        self.date = date or b'0 0'
        self.desc = desc
        self.parents = parents  # will be converted and used as parents
        self.optparents = optparents or []  # will be used if already converted
        self.branch = branch
        self.rev = rev
        self.extra = extra or {}
        self.sortkey = sortkey
        self.saverev = saverev
        self.phase = phase
        self.ctx = ctx  # for hg to hg conversions


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

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

        self.encoding = b'utf-8'

    def checkhexformat(self, revstr, mapname=b'splicemap'):
        """ fails if revstr is not a 40 byte hex. mercurial and git both uses
            such format for their revision numbering
        """
        if not re.match(br'[0-9a-fA-F]{40,40}$', revstr):
            raise error.Abort(
                _(b'%s entry %s is not a valid revision identifier')
                % (mapname, revstr)
            )

    def before(self):
        pass

    def after(self):
        pass

    def targetfilebelongstosource(self, targetfilename):
        """Returns true if the given targetfile belongs to the source repo. This
        is useful when only a subdirectory of the target belongs to the source
        repo."""
        # For normal full repo converts, this is always True.
        return True

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

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

    def getfile(self, name, rev):
        """Return a pair (data, mode) where data is the file content
        as a string and mode one of '', 'x' or 'l'. rev is the
        identifier returned by a previous call to getchanges().
        Data is None if file is missing/deleted in rev.
        """
        raise NotImplementedError

    def getchanges(self, version, full):
        """Returns a tuple of (files, copies, cleanp2).

        files is a sorted list of (filename, id) tuples for all files
        changed between version and its first parent returned by
        getcommit(). If full, all files in that revision is returned.
        id is the source revision id of the file.

        copies is a dictionary of dest: source

        cleanp2 is the set of files filenames that are clean against p2.
        (Files that are clean against p1 are already not in files (unless
        full). This makes it possible to handle p2 clean files similarly.)
        """
        raise NotImplementedError

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

    def numcommits(self):
        """Return the number of commits in this source.

        If unknown, return None.
        """
        return None

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

        Tag names must be UTF-8 strings.
        """
        raise NotImplementedError

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

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

    def hasnativeorder(self):
        """Return true if this source has a meaningful, native revision
        order. For instance, Mercurial revisions are store sequentially
        while there is no such global ordering with Darcs.
        """
        return False

    def hasnativeclose(self):
        """Return true if this source has ability to close branch.
        """
        return False

    def lookuprev(self, rev):
        """If rev is a meaningful revision reference in source, return
        the referenced identifier in the same format used by getcommit().
        return None otherwise.
        """
        return None

    def getbookmarks(self):
        """Return the bookmarks as a dictionary of name: revision

        Bookmark names are to be UTF-8 strings.
        """
        return {}

    def checkrevformat(self, revstr, mapname=b'splicemap'):
        """revstr is a string that describes a revision in the given
           source control system.  Return true if revstr has correct
           format.
        """
        return True


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

    def __init__(self, ui, repotype, 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 = []
        self.repotype = repotype

    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 putcommit(
        self, files, copies, parents, commit, source, revmap, full, cleanp2
    ):
        """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.  'files' is a list of (path, version) tuples,
        'copies' is a dictionary mapping destinations to sources,
        'source' is the source repository, and 'revmap' is a mapfile
        of source revisions to converted revisions. Only getfile() and
        lookuprev() should be called on 'source'. 'full' means that 'files'
        is complete and all other files should be removed.
        'cleanp2' is a set of the filenames that are unchanged from p2
        (only in the common merge case where there two parents).

        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, ...} where tagname is an UTF-8 string.
        Return a pair (tag_revision, tag_parent_revision), or (None, None)
        if nothing was changed.
        """
        raise NotImplementedError

    def setbranch(self, branch, pbranches):
        """Set the current branch name. Called before the first putcommit
        on the branch.
        branch: branch name for subsequent commits
        pbranches: (converted parent revision, parent branch) tuples"""

    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.
        """

    def before(self):
        pass

    def after(self):
        pass

    def putbookmarks(self, bookmarks):
        """Put bookmarks into sink.

        bookmarks: {bookmarkname: sink_rev_id, ...}
        where bookmarkname is an UTF-8 string.
        """

    def hascommitfrommap(self, rev):
        """Return False if a rev mentioned in a filemap is known to not be
        present."""
        raise NotImplementedError

    def hascommitforsplicemap(self, rev):
        """This method is for the special needs for splicemap handling and not
        for general use. Returns True if the sink contains rev, aborts on some
        special cases."""
        raise NotImplementedError


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):
        kwargs = pycompat.byteskwargs(kwargs)
        cmdline = [self.command, cmd] + list(args)
        for k, v in pycompat.iteritems(kwargs):
            if len(k) == 1:
                cmdline.append(b'-' + k)
            else:
                cmdline.append(b'--' + k.replace(b'_', b'-'))
            try:
                if len(k) == 1:
                    cmdline.append(b'' + v)
                else:
                    cmdline[-1] += b'=' + v
            except TypeError:
                pass
        cmdline = [procutil.shellquote(arg) for arg in cmdline]
        if not self.ui.debugflag:
            cmdline += [b'2>', pycompat.bytestr(os.devnull)]
        cmdline = b' '.join(cmdline)
        return cmdline

    def _run(self, cmd, *args, **kwargs):
        def popen(cmdline):
            p = subprocess.Popen(
                procutil.tonativestr(cmdline),
                shell=True,
                bufsize=-1,
                close_fds=procutil.closefds,
                stdout=subprocess.PIPE,
            )
            return p

        return self._dorun(popen, cmd, *args, **kwargs)

    def _run2(self, cmd, *args, **kwargs):
        return self._dorun(procutil.popen2, cmd, *args, **kwargs)

    def _run3(self, cmd, *args, **kwargs):
        return self._dorun(procutil.popen3, cmd, *args, **kwargs)

    def _dorun(self, openfunc, cmd, *args, **kwargs):
        cmdline = self._cmdline(cmd, *args, **kwargs)
        self.ui.debug(b'running: %s\n' % (cmdline,))
        self.prerun()
        try:
            return openfunc(cmdline)
        finally:
            self.postrun()

    def run(self, cmd, *args, **kwargs):
        p = self._run(cmd, *args, **kwargs)
        output = p.communicate()[0]
        self.ui.debug(output)
        return output, p.returncode

    def runlines(self, cmd, *args, **kwargs):
        p = self._run(cmd, *args, **kwargs)
        output = p.stdout.readlines()
        p.wait()
        self.ui.debug(b''.join(output))
        return output, p.returncode

    def checkexit(self, status, output=b''):
        if status:
            if output:
                self.ui.warn(_(b'%s error:\n') % self.command)
                self.ui.warn(output)
            msg = procutil.explainexit(status)
            raise error.Abort(b'%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 runlines0(self, cmd, *args, **kwargs):
        output, status = self.runlines(cmd, *args, **kwargs)
        self.checkexit(status, b''.join(output))
        return output

    @propertycache
    def argmax(self):
        # POSIX requires at least 4096 bytes for ARG_MAX
        argmax = 4096
        try:
            argmax = os.sysconf("SC_ARG_MAX")
        except (AttributeError, ValueError):
            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).
        return argmax // 2 - 1

    def _limit_arglist(self, arglist, cmd, *args, **kwargs):
        cmdlen = len(self._cmdline(cmd, *args, **kwargs))
        limit = self.argmax - cmdlen
        numbytes = 0
        fl = []
        for fn in arglist:
            b = len(fn) + 3
            if numbytes + b < limit or len(fl) == 0:
                fl.append(fn)
                numbytes += b
            else:
                yield fl
                fl = [fn]
                numbytes = 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):
        if not self.path:
            return
        try:
            fp = open(self.path, b'rb')
        except IOError as err:
            if err.errno != errno.ENOENT:
                raise
            return
        for i, line in enumerate(util.iterfile(fp)):
            line = line.splitlines()[0].rstrip()
            if not line:
                # Ignore blank lines
                continue
            try:
                key, value = line.rsplit(b' ', 1)
            except ValueError:
                raise error.Abort(
                    _(b'syntax error in %s(%d): key/value pair expected')
                    % (self.path, i + 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, b'ab')
            except IOError as err:
                raise error.Abort(
                    _(b'could not open map file %r: %s')
                    % (self.path, encoding.strtolocal(err.strerror))
                )
        self.fp.write(util.tonativeeol(b'%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


def makedatetimestamp(t):
    """Like dateutil.makedate() but for time t instead of current time"""
    delta = datetime.datetime.utcfromtimestamp(
        t
    ) - datetime.datetime.fromtimestamp(t)
    tz = delta.days * 86400 + delta.seconds
    return t, tz