mercurial/changelog.py

packaging: stage files and dynamically generate WiX installer

Like we did for Inno, we want to make the WiX installer
"dumb" and simply consume source files from a directory
tree rather than have to define every single file in
installer files. This will greatly decrease the amount of
effort required to maintain the WiX installer since we don't
have to think that much about keeping files in sync.

This commit changes the WiX packager to populate a staging
directory as part of packaging. After it does so, it scans
that directory and dynamically generates WiX XML defining the
content within.

The IDs and GUIDs being generated are deterministic. So,
upgrades should work as expected in Windows Installer land.
(WiX has a "heat" tool that can generate XML by walking the
filesystem but it doesn't have this deterministic property,
sadly.)

As part of this change, GUIDs are now effectively reset.
So the next upgrade should be a complete wipe and replace.
This could potentially cause issues. But in my local testing,
I was able to upgrade an existing 5.1.2 install without
issue.

Compared to the previous commit, the installed files differ
in the following:

* A ReleaseNotes.txt file is now included
* A hgrc.d/editor.rc file is now generated (mercurial.rc has been
  updated to reflect this logical change to the content source)
* All files are marked as read-only. Previously, only a subset
  of files were. This should help prevent unwanted tampering.
  Although we may want to consider use cases like modifying
  template files...

This change also means that Inno and WiX are now using very
similar code for managing the install layout. This means
that on disk both packages are nearly identical. The
differences in install layout are as follows:

* Inno has a Copying.txt vs a COPYING.rtf for WiX.
  (The WiX installer wants to use RTF.)
* Inno has a Mercurial.url file that is an internet shortcut
  to www.mercurial-scm.org. (This could potentially be
  removed.)
* Inno includes msvc[mpr]90.dll files and WiX does not.
  (WiX installs the MSVC runtime via merge modules.)
* Inno includes unins000.{dat,exe} files. (WiX's state is
  managed by Windows Installer, which places things elsewhere.)

Because file lists are dynamically generated now, the test
ensuring things remain in sync has been deleted. Good riddance.

While this is a huge step towards unifying the Windows installers,
there's still some improvements that can be made. But I think
it is worth celebrating the milestone of getting both Inno
and WiX to essentially share core packaging code and workflows.
That should make it much easier to change the installers going
forward. This will aid support of Python 3.

Differential Revision: https://phab.mercurial-scm.org/D7173

# changelog.py - changelog class for mercurial
#
# Copyright 2005-2007 Matt 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 absolute_import

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

from . import (
    copies,
    encoding,
    error,
    pycompat,
    revlog,
)
from .utils import (
    dateutil,
    stringutil,
)

from .revlogutils import sidedata as sidedatamod

_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, pycompat.bytestr(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')


class appender(object):
    '''the changelog index must be updated last on disk, so we use this class
    to delay writes to it'''

    def __init__(self, vfs, name, mode, buf):
        self.data = buf
        fp = vfs(name, mode)
        self.fp = fp
        self.offset = fp.tell()
        self.size = vfs.fstat(fp).st_size
        self._end = self.size

    def end(self):
        return self._end

    def tell(self):
        return self.offset

    def flush(self):
        pass

    @property
    def closed(self):
        return self.fp.closed

    def close(self):
        self.fp.close()

    def seek(self, offset, whence=0):
        '''virtual file offset spans real file and data'''
        if whence == 0:
            self.offset = offset
        elif whence == 1:
            self.offset += offset
        elif whence == 2:
            self.offset = self.end() + offset
        if self.offset < self.size:
            self.fp.seek(self.offset)

    def read(self, count=-1):
        '''only trick here is reads that span real file and data'''
        ret = b""
        if self.offset < self.size:
            s = self.fp.read(count)
            ret = s
            self.offset += len(s)
            if count > 0:
                count -= len(s)
        if count != 0:
            doff = self.offset - self.size
            self.data.insert(0, b"".join(self.data))
            del self.data[1:]
            s = self.data[0][doff : doff + count]
            self.offset += len(s)
            ret += s
        return ret

    def write(self, s):
        self.data.append(bytes(s))
        self.offset += len(s)
        self._end += len(s)

    def __enter__(self):
        self.fp.__enter__()
        return self

    def __exit__(self, *args):
        return self.fp.__exit__(*args)


def _divertopener(opener, target):
    """build an opener that writes in 'target.a' instead of 'target'"""

    def _divert(name, mode=b'r', checkambig=False):
        if name != target:
            return opener(name, mode)
        return opener(name + b".a", mode)

    return _divert


def _delayopener(opener, target, buf):
    """build an opener that stores chunks in 'buf' instead of 'target'"""

    def _delay(name, mode=b'r', checkambig=False):
        if name != target:
            return opener(name, mode)
        return appender(opener, name, mode, buf)

    return _delay


@attr.s
class _changelogrevision(object):
    # Extensions might modify _defaultextra, so let the constructor below pass
    # it in
    extra = attr.ib()
    manifest = attr.ib(default=nullid)
    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'')


class changelogrevision(object):
    """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',
    )

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

        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

        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 files(self):
        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:
            rawindices = self._sidedata.get(sidedatamod.SD_FILESADDED)
            if not rawindices:
                return []
        else:
            rawindices = self.extra.get(b'filesadded')
        if rawindices is None:
            return None
        return copies.decodefileindices(self.files, rawindices)

    @property
    def filesremoved(self):
        if self._cpsd:
            rawindices = self._sidedata.get(sidedatamod.SD_FILESREMOVED)
            if not rawindices:
                return []
        else:
            rawindices = self.extra.get(b'filesremoved')
        if rawindices is None:
            return None
        return copies.decodefileindices(self.files, rawindices)

    @property
    def p1copies(self):
        if self._cpsd:
            rawcopies = self._sidedata.get(sidedatamod.SD_P1COPIES)
            if not rawcopies:
                return {}
        else:
            rawcopies = self.extra.get(b'p1copies')
        if rawcopies is None:
            return None
        return copies.decodecopies(self.files, rawcopies)

    @property
    def p2copies(self):
        if self._cpsd:
            rawcopies = self._sidedata.get(sidedatamod.SD_P2COPIES)
            if not rawcopies:
                return {}
        else:
            rawcopies = self.extra.get(b'p2copies')
        if rawcopies is None:
            return None
        return copies.decodecopies(self.files, rawcopies)

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


class changelog(revlog.revlog):
    def __init__(self, opener, trypending=False):
        """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.
        """
        if trypending and opener.exists(b'00changelog.i.a'):
            indexfile = b'00changelog.i.a'
        else:
            indexfile = b'00changelog.i'

        datafile = b'00changelog.d'
        revlog.revlog.__init__(
            self,
            opener,
            indexfile,
            datafile=datafile,
            checkambig=True,
            mmaplargeindex=True,
        )

        if self._initempty and (self.version & 0xFFFF == revlog.REVLOGV1):
            # changelogs don't benefit from generaldelta.

            self.version &= ~revlog.FLAG_GENERALDELTA
            self._generaldelta = 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._realopener = opener
        self._delayed = False
        self._delaybuf = None
        self._divert = False
        self.filteredrevs = frozenset()
        self._copiesstorage = opener.options.get(b'copies-storage')

    def delayupdate(self, tr):
        b"delay visibility of index updates to other readers"

        if not self._delayed:
            if len(self) == 0:
                self._divert = True
                if self._realopener.exists(self.indexfile + b'.a'):
                    self._realopener.unlink(self.indexfile + b'.a')
                self.opener = _divertopener(self._realopener, self.indexfile)
            else:
                self._delaybuf = []
                self.opener = _delayopener(
                    self._realopener, self.indexfile, self._delaybuf
                )
        self._delayed = True
        tr.addpending(b'cl-%i' % id(self), self._writepending)
        tr.addfinalize(b'cl-%i' % id(self), self._finalize)

    def _finalize(self, tr):
        b"finalize index updates"
        self._delayed = False
        self.opener = self._realopener
        # move redirected index data back into place
        if self._divert:
            assert not self._delaybuf
            tmpname = self.indexfile + b".a"
            nfile = self.opener.open(tmpname)
            nfile.close()
            self.opener.rename(tmpname, self.indexfile, checkambig=True)
        elif self._delaybuf:
            fp = self.opener(self.indexfile, b'a', checkambig=True)
            fp.write(b"".join(self._delaybuf))
            fp.close()
            self._delaybuf = None
        self._divert = False
        # split when we're done
        self._enforceinlinesize(tr)

    def _writepending(self, tr):
        b"create a file containing the unfinalized state for pretxnchangegroup"
        if self._delaybuf:
            # make a temporary copy of the index
            fp1 = self._realopener(self.indexfile)
            pendingfilename = self.indexfile + b".a"
            # register as a temp file to ensure cleanup on failure
            tr.registertmp(pendingfilename)
            # write existing data
            fp2 = self._realopener(pendingfilename, b"w")
            fp2.write(fp1.read())
            # add pending data
            fp2.write(b"".join(self._delaybuf))
            fp2.close()
            # switch modes so finalize can simply rename
            self._delaybuf = None
            self._divert = True
            self.opener = _divertopener(self._realopener, self.indexfile)

        if self._divert:
            return True

        return False

    def _enforceinlinesize(self, tr, fp=None):
        if not self._delayed:
            revlog.revlog._enforceinlinesize(self, tr, fp)

    def read(self, node):
        """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, s = self._revisiondata(node)
        c = changelogrevision(
            d, s, self._copiesstorage == b'changeset-sidedata'
        )
        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, sidedata = self._revisiondata(nodeorrev)
        return changelogrevision(
            text, sidedata, self._copiesstorage == b'changeset-sidedata'
        )

    def readfiles(self, node):
        """
        short version of read that only returns the files modified by the cset
        """
        text = self.revision(node)
        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,
        p1copies=None,
        p2copies=None,
        filesadded=None,
        filesremoved=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)
        sidedata = None
        if extra is not None:
            for name in (
                b'p1copies',
                b'p2copies',
                b'filesadded',
                b'filesremoved',
            ):
                extra.pop(name, None)
        if p1copies is not None:
            p1copies = copies.encodecopies(sortedfiles, p1copies)
        if p2copies is not None:
            p2copies = copies.encodecopies(sortedfiles, p2copies)
        if filesadded is not None:
            filesadded = copies.encodefileindices(sortedfiles, filesadded)
        if filesremoved is not None:
            filesremoved = copies.encodefileindices(sortedfiles, filesremoved)
        if self._copiesstorage == b'extra':
            extrasentries = p1copies, p2copies, filesadded, filesremoved
            if extra is None and any(x is not None for x in extrasentries):
                extra = {}
            if p1copies is not None:
                extra[b'p1copies'] = p1copies
            if p2copies is not None:
                extra[b'p2copies'] = p2copies
            if filesadded is not None:
                extra[b'filesadded'] = filesadded
            if filesremoved is not None:
                extra[b'filesremoved'] = filesremoved
        elif self._copiesstorage == b'changeset-sidedata':
            sidedata = {}
            if p1copies:
                sidedata[sidedatamod.SD_P1COPIES] = p1copies
            if p2copies:
                sidedata[sidedatamod.SD_P2COPIES] = p2copies
            if filesadded:
                sidedata[sidedatamod.SD_FILESADDED] = filesadded
            if filesremoved:
                sidedata[sidedatamod.SD_FILESREMOVED] = filesremoved
            if not sidedata:
                sidedata = None

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

    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."""
        extra = self.read(rev)[5]
        return encoding.tolocal(extra.get(b"branch")), b'close' in extra

    def _nodeduplicatecallback(self, transaction, node):
        # 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(self.rev(node))