# bundlerepo.py - repository class for viewing uncompressed bundles

#

# Copyright 2006, 2007 Benoit Boissinot <bboissin@gmail.com>

#

# This software may be used and distributed according to the terms of the

# GNU General Public License version 2 or any later version.

"""Repository class for viewing uncompressed bundles.

This provides a read-only repository interface to bundles as if they

were part of the actual repository.

"""

from __future__ import absolute_import

import os

import shutil

from .i18n import _

from .node import nullid

from . import (

    bundle2,

    changegroup,

    changelog,

    cmdutil,

    discovery,

    error,

    exchange,

    filelog,

    localrepo,

    manifest,

    mdiff,

    node as nodemod,

    pathutil,

    phases,

    pycompat,

    revlog,

    util,

    vfs as vfsmod,

)

class bundlerevlog(revlog.revlog):

    def __init__(self, opener, indexfile, cgunpacker, linkmapper):

        # How it works:

        # To retrieve a revision, we need to know the offset of the revision in

        # the bundle (an unbundle object). We store this offset in the index

        # (start). The base of the delta is stored in the base field.

        #

        # To differentiate a rev in the bundle from a rev in the revlog, we

        # check revision against repotiprev.

        opener = vfsmod.readonlyvfs(opener)

        revlog.revlog.__init__(self, opener, indexfile)

        self.bundle = cgunpacker

        n = len(self)

        self.repotiprev = n - 1

        self.bundlerevs = set() # used by 'bundle()' revset expression

        for deltadata in cgunpacker.deltaiter():

            node, p1, p2, cs, deltabase, delta, flags = deltadata

            size = len(delta)

            start = cgunpacker.tell() - size

            link = linkmapper(cs)

            if node in self.nodemap:

                # this can happen if two branches make the same change

                self.bundlerevs.add(self.nodemap[node])

                continue

            for p in (p1, p2):

                if p not in self.nodemap:

                    raise error.LookupError(p, self.indexfile,

                                            _("unknown parent"))

            if deltabase not in self.nodemap:

                raise LookupError(deltabase, self.indexfile,

                                  _('unknown delta base'))

            baserev = self.rev(deltabase)

            # start, size, full unc. size, base (unused), link, p1, p2, node

            e = (revlog.offset_type(start, flags), size, -1, baserev, link,

                 self.rev(p1), self.rev(p2), node)

            self.nodemap[node] = n

            self.bundlerevs.add(n)

            n += 1

    def _chunk(self, rev, df=None):

        # Warning: in case of bundle, the diff is against what we stored as

        # delta base, not against rev - 1

        # XXX: could use some caching

        if rev <= self.repotiprev:

            return revlog.revlog._chunk(self, rev)

        self.bundle.seek(self.start(rev))

        return self.bundle.read(self.length(rev))

    def revdiff(self, rev1, rev2):

        """return or calculate a delta between two revisions"""

        if rev1 > self.repotiprev and rev2 > self.repotiprev:

            # hot path for bundle

            revb = self.index[rev2][3]

            if revb == rev1:

                return self._chunk(rev2)

        elif rev1 <= self.repotiprev and rev2 <= self.repotiprev:

            return revlog.revlog.revdiff(self, rev1, rev2)

        return mdiff.textdiff(self.revision(rev1, raw=True),

                              self.revision(rev2, raw=True))

    def revision(self, nodeorrev, _df=None, raw=False):

        """return an uncompressed revision of a given node or revision

        number.

        """

        if isinstance(nodeorrev, int):

            rev = nodeorrev

            node = self.node(rev)

        else:

            node = nodeorrev

            rev = self.rev(node)

        if node == nullid:

            return ""

        rawtext = None

        chain = []

        iterrev = rev

        # reconstruct the revision if it is from a changegroup

        while iterrev > self.repotiprev:

            if self._cache and self._cache[1] == iterrev:

                rawtext = self._cache[2]

                break

            chain.append(iterrev)

            iterrev = self.index[iterrev][3]

        if rawtext is None:

            rawtext = self.baserevision(iterrev)

        while chain:

            delta = self._chunk(chain.pop())

            rawtext = mdiff.patches(rawtext, [delta])

        text, validatehash = self._processflags(rawtext, self.flags(rev),

                                                'read', raw=raw)

        if validatehash:

            self.checkhash(text, node, rev=rev)

        self._cache = (node, rev, rawtext)

        return text

    def baserevision(self, nodeorrev):

        # Revlog subclasses may override 'revision' method to modify format of

        # content retrieved from revlog. To use bundlerevlog with such class one

        # needs to override 'baserevision' and make more specific call here.

        return revlog.revlog.revision(self, nodeorrev, raw=True)

    def addrevision(self, *args, **kwargs):

        raise NotImplementedError

    def addgroup(self, *args, **kwargs):

        raise NotImplementedError

    def strip(self, *args, **kwargs):

        raise NotImplementedError

    def checksize(self):

        raise NotImplementedError

class bundlechangelog(bundlerevlog, changelog.changelog):

    def __init__(self, opener, cgunpacker):

        changelog.changelog.__init__(self, opener)

        linkmapper = lambda x: x

        bundlerevlog.__init__(self, opener, self.indexfile, cgunpacker,

                              linkmapper)

    def baserevision(self, nodeorrev):

        # Although changelog doesn't override 'revision' method, some extensions

        # may replace this class with another that does. Same story with

        # manifest and filelog classes.

        # This bypasses filtering on changelog.node() and rev() because we need

        # revision text of the bundle base even if it is hidden.

        oldfilter = self.filteredrevs

        try:

            self.filteredrevs = ()

            return changelog.changelog.revision(self, nodeorrev, raw=True)

        finally:

            self.filteredrevs = oldfilter

class bundlemanifest(bundlerevlog, manifest.manifestrevlog):

    def __init__(self, opener, cgunpacker, linkmapper, dirlogstarts=None,

                 dir=''):

        manifest.manifestrevlog.__init__(self, opener, dir=dir)

        bundlerevlog.__init__(self, opener, self.indexfile, cgunpacker,

                              linkmapper)

        if dirlogstarts is None:

            dirlogstarts = {}

            if self.bundle.version == "03":

                dirlogstarts = _getfilestarts(self.bundle)

        self._dirlogstarts = dirlogstarts

        self._linkmapper = linkmapper

    def baserevision(self, nodeorrev):

        node = nodeorrev

        if isinstance(node, int):

            node = self.node(node)

        if node in self.fulltextcache:

            result = '%s' % self.fulltextcache[node]

        else:

            result = manifest.manifestrevlog.revision(self, nodeorrev, raw=True)

        return result

    def dirlog(self, d):

        if d in self._dirlogstarts:

            self.bundle.seek(self._dirlogstarts[d])

            return bundlemanifest(

                self.opener, self.bundle, self._linkmapper,

                self._dirlogstarts, dir=d)

        return super(bundlemanifest, self).dirlog(d)

class bundlefilelog(filelog.filelog):

    def __init__(self, opener, path, cgunpacker, linkmapper):

        filelog.filelog.__init__(self, opener, path)

        self._revlog = bundlerevlog(opener, self.indexfile,

                                    cgunpacker, linkmapper)

    def baserevision(self, nodeorrev):

        return filelog.filelog.revision(self, nodeorrev, raw=True)

class bundlepeer(localrepo.localpeer):

    def canpush(self):

        return False

class bundlephasecache(phases.phasecache):

    def __init__(self, *args, **kwargs):

        super(bundlephasecache, self).__init__(*args, **kwargs)

        if util.safehasattr(self, 'opener'):

            self.opener = vfsmod.readonlyvfs(self.opener)

    def write(self):

        raise NotImplementedError

    def _write(self, fp):

        raise NotImplementedError

    def _updateroots(self, phase, newroots, tr):

        self.phaseroots[phase] = newroots

        self.invalidate()

        self.dirty = True

def _getfilestarts(cgunpacker):

    filespos = {}

    for chunkdata in iter(cgunpacker.filelogheader, {}):

        fname = chunkdata['filename']

        filespos[fname] = cgunpacker.tell()

        for chunk in iter(lambda: cgunpacker.deltachunk(None), {}):

            pass

    return filespos

class bundlerepository(localrepo.localrepository):

    """A repository instance that is a union of a local repo and a bundle.

    Instances represent a read-only repository composed of a local repository

    with the contents of a bundle file applied. The repository instance is

    conceptually similar to the state of a repository after an

    ``hg unbundle`` operation. However, the contents of the bundle are never

    applied to the actual base repository.

    """

    def __init__(self, ui, repopath, bundlepath):

        self._tempparent = None

        try:

            localrepo.localrepository.__init__(self, ui, repopath)

        except error.RepoError:

            self._tempparent = pycompat.mkdtemp()

            localrepo.instance(ui, self._tempparent, 1)

            localrepo.localrepository.__init__(self, ui, self._tempparent)

        self.ui.setconfig('phases', 'publish', False, 'bundlerepo')

        if repopath:

            self._url = 'bundle:' + util.expandpath(repopath) + '+' + bundlepath

        else:

            self._url = 'bundle:' + bundlepath

        self.tempfile = None

        f = util.posixfile(bundlepath, "rb")

        bundle = exchange.readbundle(ui, f, bundlepath)

        if isinstance(bundle, bundle2.unbundle20):

            self._bundlefile = bundle

            self._cgunpacker = None

            cgpart = None

            for part in bundle.iterparts(seekable=True):

                if part.type == 'changegroup':

                    if cgpart:

                        raise NotImplementedError("can't process "

                                                  "multiple changegroups")

                    cgpart = part

                self._handlebundle2part(bundle, part)

            if not cgpart:

                raise error.Abort(_("No changegroups found"))

            # This is required to placate a later consumer, which expects

            # the payload offset to be at the beginning of the changegroup.

            # We need to do this after the iterparts() generator advances

            # because iterparts() will seek to end of payload after the

            # generator returns control to iterparts().

            cgpart.seek(0, os.SEEK_SET)

        elif isinstance(bundle, changegroup.cg1unpacker):

            if bundle.compressed():

                f = self._writetempbundle(bundle.read, '.hg10un',

                                          header='HG10UN')

                bundle = exchange.readbundle(ui, f, bundlepath, self.vfs)

            self._bundlefile = bundle

            self._cgunpacker = bundle

        else:

            raise error.Abort(_('bundle type %s cannot be read') %

                              type(bundle))

        # dict with the mapping 'filename' -> position in the changegroup.

        self._cgfilespos = {}

        self.firstnewrev = self.changelog.repotiprev + 1

        phases.retractboundary(self, None, phases.draft,

                               [ctx.node() for ctx in self[self.firstnewrev:]])

    def _handlebundle2part(self, bundle, part):

        if part.type != 'changegroup':

            return

        cgstream = part

        version = part.params.get('version', '01')

        legalcgvers = changegroup.supportedincomingversions(self)

        if version not in legalcgvers:

            msg = _('Unsupported changegroup version: %s')

            raise error.Abort(msg % version)

        if bundle.compressed():

            cgstream = self._writetempbundle(part.read, '.cg%sun' % version)

        self._cgunpacker = changegroup.getunbundler(version, cgstream, 'UN')

    def _writetempbundle(self, readfn, suffix, header=''):

        """Write a temporary file to disk

        """

        fdtemp, temp = self.vfs.mkstemp(prefix="hg-bundle-",

                                        suffix=suffix)

        self.tempfile = temp

        with os.fdopen(fdtemp, r'wb') as fptemp:

            fptemp.write(header)

            while True:

                chunk = readfn(2**18)

                if not chunk:

                    break

                fptemp.write(chunk)

        return self.vfs.open(self.tempfile, mode="rb")

    @localrepo.unfilteredpropertycache

    def _phasecache(self):

        return bundlephasecache(self, self._phasedefaults)

    @localrepo.unfilteredpropertycache

    def changelog(self):

        # consume the header if it exists

        self._cgunpacker.changelogheader()