mercurial/changelog.py

interfaces: introduce and use a protocol class for the `charencoding` module

See f2832de2a46c for details when this was done for the `bdiff` module.

This lets us dump the hack where the `pure` implementation was imported during
the type checking phase to provide signatures for the module methods it
provides.  Now the protocol classes are starting to shine, because these methods
are provided by `pure.charencoding` and `cext.parsers`, and references to
`cffi.charencoding` and `cext.charencoding` are forwarded to them as appropriate
by the `policy` module.  But none of that matters, as long as the module
returned provides the listed methods.

The interface was copy/pasted from the `pure` module, but `jsonescapeu8fallback`
is omitted because it is accessed from the `pure` module directly when the
escaping fails in the primary module's `jsonescapeu8()`.

# changelog.py - changelog class for mercurial
#
# Copyright 2005-2007 Olivia Mackall <[e-mail]>
#
# 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 annotations

import typing

from .i18n import _
from .node import (
    bin,
    hex,
)
from .thirdparty import attr

# Force pytype to use the non-vendored package
if typing.TYPE_CHECKING:
    # noinspection PyPackageRequirements
    import attr

from . import (
    encoding,
    error,
    metadata,
    pycompat,
    revlog,
)
from .utils import (
    dateutil,
    stringutil,
)
from .revlogutils import (
    constants as revlog_constants,
    flagutil,
)

_defaultextra = {b'branch': b'default'}


def _string_escape(text):
    """
    >>> from .pycompat import bytechr as chr
    >>> d = {b'nl': chr(10), b'bs': chr(92), b'cr': chr(13), b'nul': chr(0)}
    >>> s = b"ab%(nl)scd%(bs)s%(bs)sn%(nul)s12ab%(cr)scd%(bs)s%(nl)s" % d
    >>> s
    'ab\\ncd\\\\\\\\n\\x0012ab\\rcd\\\\\\n'
    >>> res = _string_escape(s)
    >>> s == _string_unescape(res)
    True
    """
    # subset of the string_escape codec
    text = (
        text.replace(b'\\', b'\\\\')
        .replace(b'\n', b'\\n')
        .replace(b'\r', b'\\r')
    )
    return text.replace(b'\0', b'\\0')


def _string_unescape(text):
    if b'\\0' in text:
        # fix up \0 without getting into trouble with \\0
        text = text.replace(b'\\\\', b'\\\\\n')
        text = text.replace(b'\\0', b'\0')
        text = text.replace(b'\n', b'')
    return stringutil.unescapestr(text)


def decodeextra(text):
    """
    >>> from .pycompat import bytechr as chr
    >>> sorted(decodeextra(encodeextra({b'foo': b'bar', b'baz': chr(0) + b'2'})
    ...                    ).items())
    [('baz', '\\x002'), ('branch', 'default'), ('foo', 'bar')]
    >>> sorted(decodeextra(encodeextra({b'foo': b'bar',
    ...                                 b'baz': chr(92) + chr(0) + b'2'})
    ...                    ).items())
    [('baz', '\\\\\\x002'), ('branch', 'default'), ('foo', 'bar')]
    """
    extra = _defaultextra.copy()
    for l in text.split(b'\0'):
        if l:
            k, v = _string_unescape(l).split(b':', 1)
            extra[k] = v
    return extra


def encodeextra(d):
    # keys must be sorted to produce a deterministic changelog entry
    items = [_string_escape(b'%s:%s' % (k, d[k])) for k in sorted(d)]
    return b"\0".join(items)


def stripdesc(desc):
    """strip trailing whitespace and leading and trailing empty lines"""
    return b'\n'.join([l.rstrip() for l in desc.splitlines()]).strip(b'\n')


@attr.s
class _changelogrevision:
    # Extensions might modify _defaultextra, so let the constructor below pass
    # it in
    extra = attr.ib()
    manifest = attr.ib()
    user = attr.ib(default=b'')
    date = attr.ib(default=(0, 0))
    files = attr.ib(default=attr.Factory(list))
    filesadded = attr.ib(default=None)
    filesremoved = attr.ib(default=None)
    p1copies = attr.ib(default=None)
    p2copies = attr.ib(default=None)
    description = attr.ib(default=b'')
    branchinfo = attr.ib(default=(_defaultextra[b'branch'], False))


class changelogrevision:
    """Holds results of a parsed changelog revision.

    Changelog revisions consist of multiple pieces of data, including
    the manifest node, user, and date. This object exposes a view into
    the parsed object.
    """

    __slots__ = (
        '_offsets',
        '_text',
        '_sidedata',
        '_cpsd',
        '_changes',
    )

    def __new__(cls, cl, text, sidedata, cpsd):
        if not text:
            return _changelogrevision(extra=_defaultextra, manifest=cl.nullid)

        self = super(changelogrevision, cls).__new__(cls)
        # We could return here and implement the following as an __init__.
        # But doing it here is equivalent and saves an extra function call.

        # format used:
        # nodeid\n        : manifest node in ascii
        # user\n          : user, no \n or \r allowed
        # time tz extra\n : date (time is int or float, timezone is int)
        #                 : extra is metadata, encoded and separated by '\0'
        #                 : older versions ignore it
        # files\n\n       : files modified by the cset, no \n or \r allowed
        # (.*)            : comment (free text, ideally utf-8)
        #
        # changelog v0 doesn't use extra

        nl1 = text.index(b'\n')
        nl2 = text.index(b'\n', nl1 + 1)
        nl3 = text.index(b'\n', nl2 + 1)

        # The list of files may be empty. Which means nl3 is the first of the
        # double newline that precedes the description.
        if text[nl3 + 1 : nl3 + 2] == b'\n':
            doublenl = nl3
        else:
            doublenl = text.index(b'\n\n', nl3 + 1)

        self._offsets = (nl1, nl2, nl3, doublenl)
        self._text = text
        self._sidedata = sidedata
        self._cpsd = cpsd
        self._changes = None

        return self

    @property
    def manifest(self):
        return bin(self._text[0 : self._offsets[0]])

    @property
    def user(self):
        off = self._offsets
        return encoding.tolocal(self._text[off[0] + 1 : off[1]])

    @property
    def _rawdate(self):
        off = self._offsets
        dateextra = self._text[off[1] + 1 : off[2]]
        return dateextra.split(b' ', 2)[0:2]

    @property
    def _rawextra(self):
        off = self._offsets
        dateextra = self._text[off[1] + 1 : off[2]]
        fields = dateextra.split(b' ', 2)
        if len(fields) != 3:
            return None

        return fields[2]

    @property
    def date(self):
        raw = self._rawdate
        time = float(raw[0])
        # Various tools did silly things with the timezone.
        try:
            timezone = int(raw[1])
        except ValueError:
            timezone = 0

        return time, timezone

    @property
    def extra(self):
        raw = self._rawextra
        if raw is None:
            return _defaultextra

        return decodeextra(raw)

    @property
    def changes(self):
        if self._changes is not None:
            return self._changes
        if self._cpsd:
            changes = metadata.decode_files_sidedata(self._sidedata)
        else:
            changes = metadata.ChangingFiles(
                touched=self.files or (),
                added=self.filesadded or (),
                removed=self.filesremoved or (),
                p1_copies=self.p1copies or {},
                p2_copies=self.p2copies or {},
            )
        self._changes = changes
        return changes

    @property
    def files(self):
        if self._cpsd:
            return sorted(self.changes.touched)
        off = self._offsets
        if off[2] == off[3]:
            return []

        return self._text[off[2] + 1 : off[3]].split(b'\n')

    @property
    def filesadded(self):
        if self._cpsd:
            return self.changes.added
        else:
            rawindices = self.extra.get(b'filesadded')
        if rawindices is None:
            return None
        return metadata.decodefileindices(self.files, rawindices)

    @property
    def filesremoved(self):
        if self._cpsd:
            return self.changes.removed
        else:
            rawindices = self.extra.get(b'filesremoved')
        if rawindices is None:
            return None
        return metadata.decodefileindices(self.files, rawindices)

    @property
    def p1copies(self):
        if self._cpsd:
            return self.changes.copied_from_p1
        else:
            rawcopies = self.extra.get(b'p1copies')
        if rawcopies is None:
            return None
        return metadata.decodecopies(self.files, rawcopies)

    @property
    def p2copies(self):
        if self._cpsd:
            return self.changes.copied_from_p2
        else:
            rawcopies = self.extra.get(b'p2copies')
        if rawcopies is None:
            return None
        return metadata.decodecopies(self.files, rawcopies)

    @property
    def description(self):
        return encoding.tolocal(self._text[self._offsets[3] + 2 :])

    @property
    def branchinfo(self):
        extra = self.extra
        return encoding.tolocal(extra.get(b"branch")), b'close' in extra


class changelog(revlog.revlog):
    def __init__(self, opener, trypending=False, concurrencychecker=None):
        """Load a changelog revlog using an opener.

        If ``trypending`` is true, we attempt to load the index from a
        ``00changelog.i.a`` file instead of the default ``00changelog.i``.
        The ``00changelog.i.a`` file contains index (and possibly inline
        revision) data for a transaction that hasn't been finalized yet.
        It exists in a separate file to facilitate readers (such as
        hooks processes) accessing data before a transaction is finalized.

        ``concurrencychecker`` will be passed to the revlog init function, see
        the documentation there.
        """
        revlog.revlog.__init__(
            self,
            opener,
            target=(revlog_constants.KIND_CHANGELOG, None),
            radix=b'00changelog',
            checkambig=True,
            mmaplargeindex=True,
            persistentnodemap=opener.options.get(b'persistent-nodemap', False),
            concurrencychecker=concurrencychecker,
            trypending=trypending,
            may_inline=False,
        )

        if self._initempty and (self._format_version == revlog.REVLOGV1):
            # changelogs don't benefit from generaldelta.

            self._format_flags &= ~revlog.FLAG_GENERALDELTA
            self.delta_config.general_delta = False

        # Delta chains for changelogs tend to be very small because entries
        # tend to be small and don't delta well with each. So disable delta
        # chains.
        self._storedeltachains = False

        self._v2_delayed = False
        self._filteredrevs = frozenset()
        self._filteredrevs_hashcache = {}
        self._copiesstorage = opener.options.get(b'copies-storage')

    def __contains__(self, rev):
        return (0 <= rev < len(self)) and rev not in self._filteredrevs

    @property
    def filteredrevs(self):
        return self._filteredrevs

    @filteredrevs.setter
    def filteredrevs(self, val):
        # Ensure all updates go through this function
        assert isinstance(val, frozenset)
        self._filteredrevs = val
        self._filteredrevs_hashcache = {}

    def _write_docket(self, tr):
        if not self._v2_delayed:
            super(changelog, self)._write_docket(tr)

    def delayupdate(self, tr):
        """delay visibility of index updates to other readers"""
        assert not self._inner.is_open
        assert not self._may_inline
        # enforce that older changelog that are still inline are split at the
        # first opportunity.
        if self._inline:
            self._enforceinlinesize(tr)
        if self._docket is not None:
            self._v2_delayed = True
        else:
            new_index = self._inner.delay()
            if new_index is not None:
                self._indexfile = new_index
                tr.registertmp(new_index)
        # use "000" as prefix to make sure we run before the spliting of legacy
        # inline changelog..
        tr.addpending(b'000-cl-%i' % id(self), self._writepending)
        tr.addfinalize(b'000-cl-%i' % id(self), self._finalize)

    def _finalize(self, tr):
        """finalize index updates"""
        assert not self._inner.is_open
        if self._docket is not None:
            self._docket.write(tr)
            self._v2_delayed = False
        else:
            new_index_file = self._inner.finalize_pending()
            self._indexfile = new_index_file
            if self._inline:
                msg = 'changelog should not be inline at that point'
                raise error.ProgrammingError(msg)

    def _writepending(self, tr):
        """create a file containing the unfinalized state for
        pretxnchangegroup"""
        assert not self._inner.is_open
        if self._docket:
            any_pending = self._docket.write(tr, pending=True)
            self._v2_delayed = False
        else:
            new_index, any_pending = self._inner.write_pending()
            if new_index is not None:
                self._indexfile = new_index
                tr.registertmp(new_index)
        return any_pending

    def _enforceinlinesize(self, tr):
        if not self.is_delaying:
            revlog.revlog._enforceinlinesize(self, tr)

    def read(self, nodeorrev):
        """Obtain data from a parsed changelog revision.

        Returns a 6-tuple of:

           - manifest node in binary
           - author/user as a localstr
           - date as a 2-tuple of (time, timezone)
           - list of files
           - commit message as a localstr
           - dict of extra metadata

        Unless you need to access all fields, consider calling
        ``changelogrevision`` instead, as it is faster for partial object
        access.
        """
        d = self._revisiondata(nodeorrev)
        sidedata = self.sidedata(nodeorrev)
        copy_sd = self._copiesstorage == b'changeset-sidedata'
        c = changelogrevision(self, d, sidedata, copy_sd)
        return (c.manifest, c.user, c.date, c.files, c.description, c.extra)

    def changelogrevision(self, nodeorrev):
        """Obtain a ``changelogrevision`` for a node or revision."""
        text = self._revisiondata(nodeorrev)
        sidedata = self.sidedata(nodeorrev)
        return changelogrevision(
            self, text, sidedata, self._copiesstorage == b'changeset-sidedata'
        )

    def readfiles(self, nodeorrev):
        """
        short version of read that only returns the files modified by the cset
        """
        text = self.revision(nodeorrev)
        if not text:
            return []
        last = text.index(b"\n\n")
        l = text[:last].split(b'\n')
        return l[3:]

    def add(
        self,
        manifest,
        files,
        desc,
        transaction,
        p1,
        p2,
        user,
        date=None,
        extra=None,
    ):
        # Convert to UTF-8 encoded bytestrings as the very first
        # thing: calling any method on a localstr object will turn it
        # into a str object and the cached UTF-8 string is thus lost.
        user, desc = encoding.fromlocal(user), encoding.fromlocal(desc)

        user = user.strip()
        # An empty username or a username with a "\n" will make the
        # revision text contain two "\n\n" sequences -> corrupt
        # repository since read cannot unpack the revision.
        if not user:
            raise error.StorageError(_(b"empty username"))
        if b"\n" in user:
            raise error.StorageError(
                _(b"username %r contains a newline") % pycompat.bytestr(user)
            )

        desc = stripdesc(desc)

        if date:
            parseddate = b"%d %d" % dateutil.parsedate(date)
        else:
            parseddate = b"%d %d" % dateutil.makedate()
        if extra:
            branch = extra.get(b"branch")
            if branch in (b"default", b""):
                del extra[b"branch"]
            elif branch in (b".", b"null", b"tip"):
                raise error.StorageError(
                    _(b'the name \'%s\' is reserved') % branch
                )
        sortedfiles = sorted(files.touched)
        flags = 0
        sidedata = None
        if self._copiesstorage == b'changeset-sidedata':
            if files.has_copies_info:
                flags |= flagutil.REVIDX_HASCOPIESINFO
            sidedata = metadata.encode_files_sidedata(files)

        if extra:
            extra = encodeextra(extra)
            parseddate = b"%s %s" % (parseddate, extra)
        l = [hex(manifest), user, parseddate] + sortedfiles + [b"", desc]
        text = b"\n".join(l)
        rev = self.addrevision(
            text, transaction, len(self), p1, p2, sidedata=sidedata, flags=flags
        )
        return self.node(rev)

    def branchinfo(self, rev):
        """return the branch name and open/close state of a revision

        This function exists because creating a changectx object
        just to access this is costly."""
        return self.changelogrevision(rev).branchinfo

    def _nodeduplicatecallback(self, transaction, rev):
        # keep track of revisions that got "re-added", eg: unbunde of know rev.
        #
        # We track them in a list to preserve their order from the source bundle
        duplicates = transaction.changes.setdefault(b'revduplicates', [])
        duplicates.append(rev)