# wrapper.py - methods wrapping core mercurial logic

#

# Copyright 2017 Facebook, Inc.

#

# 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 hashlib

from mercurial.i18n import _

from mercurial.node import bin, hex, nullid, short

from mercurial import (

    bundle2,

    changegroup,

    cmdutil,

    context,

    error,

    exchange,

    exthelper,

    localrepo,

    repository,

    revlog,

    scmutil,

    upgrade,

    util,

    vfs as vfsmod,

    wireprotov1server,

)

from mercurial.utils import (

    storageutil,

    stringutil,

)

from ..largefiles import lfutil

from . import (

    blobstore,

    pointer,

)

eh = exthelper.exthelper()

@eh.wrapfunction(localrepo, 'makefilestorage')

def localrepomakefilestorage(orig, requirements, features, **kwargs):

    if b'lfs' in requirements:

        features.add(repository.REPO_FEATURE_LFS)

    return orig(requirements=requirements, features=features, **kwargs)

@eh.wrapfunction(changegroup, 'allsupportedversions')

def allsupportedversions(orig, ui):

    versions = orig(ui)

    versions.add('03')

    return versions

@eh.wrapfunction(wireprotov1server, '_capabilities')

def _capabilities(orig, repo, proto):

    '''Wrap server command to announce lfs server capability'''

    caps = orig(repo, proto)

    if util.safehasattr(repo.svfs, 'lfslocalblobstore'):

        # Advertise a slightly different capability when lfs is *required*, so

        # that the client knows it MUST load the extension.  If lfs is not

        # required on the server, there's no reason to autoload the extension

        # on the client.

        if b'lfs' in repo.requirements:

            caps.append('lfs-serve')

        caps.append('lfs')

    return caps

def bypasscheckhash(self, text):

    return False

def readfromstore(self, text):

    """Read filelog content from local blobstore transform for flagprocessor.

    Default tranform for flagprocessor, returning contents from blobstore.

    Returns a 2-typle (text, validatehash) where validatehash is True as the

    contents of the blobstore should be checked using checkhash.

    """

    p = pointer.deserialize(text)

    oid = p.oid()

    store = self.opener.lfslocalblobstore

    if not store.has(oid):

        p.filename = self.filename

        self.opener.lfsremoteblobstore.readbatch([p], store)

    # The caller will validate the content

    text = store.read(oid, verify=False)

    # pack hg filelog metadata

    hgmeta = {}

    for k in p.keys():

        if k.startswith('x-hg-'):

            name = k[len('x-hg-'):]

            hgmeta[name] = p[k]

    if hgmeta or text.startswith('\1\n'):

        text = storageutil.packmeta(hgmeta, text)

    return (text, True)

def writetostore(self, text):

    # hg filelog metadata (includes rename, etc)

    hgmeta, offset = storageutil.parsemeta(text)

    if offset and offset > 0:

        # lfs blob does not contain hg filelog metadata

        text = text[offset:]

    # git-lfs only supports sha256

    oid = hex(hashlib.sha256(text).digest())

    self.opener.lfslocalblobstore.write(oid, text)

    # replace contents with metadata

    longoid = 'sha256:%s' % oid

    metadata = pointer.gitlfspointer(oid=longoid, size='%d' % len(text))

    # by default, we expect the content to be binary. however, LFS could also

    # be used for non-binary content. add a special entry for non-binary data.

    # this will be used by filectx.isbinary().

    if not stringutil.binary(text):

        # not hg filelog metadata (affecting commit hash), no "x-hg-" prefix

        metadata['x-is-binary'] = '0'

    # translate hg filelog metadata to lfs metadata with "x-hg-" prefix

    if hgmeta is not None:

        for k, v in hgmeta.iteritems():

            metadata['x-hg-%s' % k] = v

    rawtext = metadata.serialize()

    return (rawtext, False)

def _islfs(rlog, node=None, rev=None):

    if rev is None:

        if node is None:

            # both None - likely working copy content where node is not ready

            return False

        rev = rlog._revlog.rev(node)

    else:

        node = rlog._revlog.node(rev)

    if node == nullid:

        return False

    flags = rlog._revlog.flags(rev)

    return bool(flags & revlog.REVIDX_EXTSTORED)

# Wrapping may also be applied by remotefilelog

def filelogaddrevision(orig, self, text, transaction, link, p1, p2,

                       cachedelta=None, node=None,

                       flags=revlog.REVIDX_DEFAULT_FLAGS, **kwds):

    # The matcher isn't available if reposetup() wasn't called.

    lfstrack = self._revlog.opener.options.get('lfstrack')

    if lfstrack:

        textlen = len(text)

        # exclude hg rename meta from file size

        meta, offset = storageutil.parsemeta(text)

        if offset:

            textlen -= offset

        if lfstrack(self._revlog.filename, textlen):

            flags |= revlog.REVIDX_EXTSTORED

    return orig(self, text, transaction, link, p1, p2, cachedelta=cachedelta,

                node=node, flags=flags, **kwds)

# Wrapping may also be applied by remotefilelog

def filelogrenamed(orig, self, node):

    if _islfs(self, node):

        if not rawtext:

            return False

        metadata = pointer.deserialize(rawtext)

        if 'x-hg-copy' in metadata and 'x-hg-copyrev' in metadata:

            return metadata['x-hg-copy'], bin(metadata['x-hg-copyrev'])

        else:

            return False

    return orig(self, node)

# Wrapping may also be applied by remotefilelog

def filelogsize(orig, self, rev):

    if _islfs(self, rev=rev):

        # fast path: use lfs metadata to answer size

        metadata = pointer.deserialize(rawtext)

        return int(metadata['size'])

    return orig(self, rev)

@eh.wrapfunction(context.basefilectx, 'cmp')

def filectxcmp(orig, self, fctx):

    """returns True if text is different than fctx"""

    # some fctx (ex. hg-git) is not based on basefilectx and do not have islfs

    if self.islfs() and getattr(fctx, 'islfs', lambda: False)():

        # fast path: check LFS oid

        p1 = pointer.deserialize(self.rawdata())

        p2 = pointer.deserialize(fctx.rawdata())

        return p1.oid() != p2.oid()

    return orig(self, fctx)

@eh.wrapfunction(context.basefilectx, 'isbinary')

def filectxisbinary(orig, self):

    if self.islfs():

        # fast path: use lfs metadata to answer isbinary

        metadata = pointer.deserialize(self.rawdata())

        # if lfs metadata says nothing, assume it's binary by default

        return bool(int(metadata.get('x-is-binary', 1)))

    return orig(self)

def filectxislfs(self):

    return _islfs(self.filelog(), self.filenode())

@eh.wrapfunction(cmdutil, '_updatecatformatter')

def _updatecatformatter(orig, fm, ctx, matcher, path, decode):

    orig(fm, ctx, matcher, path, decode)

    fm.data(rawdata=ctx[path].rawdata())

@eh.wrapfunction(scmutil, 'wrapconvertsink')

def convertsink(orig, sink):

    sink = orig(sink)

    if sink.repotype == 'hg':

        class lfssink(sink.__class__):

            def putcommit(self, files, copies, parents, commit, source, revmap,

                          full, cleanp2):

                pc = super(lfssink, self).putcommit

                node = pc(files, copies, parents, commit, source, revmap, full,

                          cleanp2)

                if 'lfs' not in self.repo.requirements:

                    ctx = self.repo[node]

                    # The file list may contain removed files, so check for

                    # membership before assuming it is in the context.

                    if any(f in ctx and ctx[f].islfs() for f, n in files):

                        self.repo.requirements.add('lfs')

                        self.repo._writerequirements()

                return node

        sink.__class__ = lfssink

    return sink

# bundlerepo uses "vfsmod.readonlyvfs(othervfs)", we need to make sure lfs

# options and blob stores are passed from othervfs to the new readonlyvfs.

@eh.wrapfunction(vfsmod.readonlyvfs, '__init__')

def vfsinit(orig, self, othervfs):

    orig(self, othervfs)

    # copy lfs related options

    for k, v in othervfs.options.items():

        if k.startswith('lfs'):

            self.options[k] = v

    # also copy lfs blobstores. note: this can run before reposetup, so lfs

    # blobstore attributes are not always ready at this time.

    for name in ['lfslocalblobstore', 'lfsremoteblobstore']:

        if util.safehasattr(othervfs, name):

            setattr(self, name, getattr(othervfs, name))

def _prefetchfiles(repo, revs, match):

    """Ensure that required LFS blobs are present, fetching them as a group if

    needed."""

    if not util.safehasattr(repo.svfs, 'lfslocalblobstore'):

        return

    pointers = []

    oids = set()

    localstore = repo.svfs.lfslocalblobstore

    for rev in revs:

        ctx = repo[rev]

        for f in ctx.walk(match):

            p = pointerfromctx(ctx, f)

            if p and p.oid() not in oids and not localstore.has(p.oid()):

                p.filename = f

                pointers.append(p)

                oids.add(p.oid())

    if pointers:

        # Recalculating the repo store here allows 'paths.default' that is set

        # on the repo by a clone command to be used for the update.

        blobstore.remote(repo).readbatch(pointers, localstore)

def _canskipupload(repo):

    # Skip if this hasn't been passed to reposetup()

    if not util.safehasattr(repo.svfs, 'lfsremoteblobstore'):

        return True

    # if remotestore is a null store, upload is a no-op and can be skipped

    return isinstance(repo.svfs.lfsremoteblobstore, blobstore._nullremote)

def candownload(repo):

    # Skip if this hasn't been passed to reposetup()

    if not util.safehasattr(repo.svfs, 'lfsremoteblobstore'):

        return False

    # if remotestore is a null store, downloads will lead to nothing

    return not isinstance(repo.svfs.lfsremoteblobstore, blobstore._nullremote)

def uploadblobsfromrevs(repo, revs):

    '''upload lfs blobs introduced by revs

    Note: also used by other extensions e. g. infinitepush. avoid renaming.

    '''

    if _canskipupload(repo):

        return

    pointers = extractpointers(repo, revs)

    uploadblobs(repo, pointers)

def prepush(pushop):

    """Prepush hook.

    Read through the revisions to push, looking for filelog entries that can be

    deserialized into metadata so that we can block the push on their upload to

    the remote blobstore.

    """

    return uploadblobsfromrevs(pushop.repo, pushop.outgoing.missing)

@eh.wrapfunction(exchange, 'push')

def push(orig, repo, remote, *args, **kwargs):

    """bail on push if the extension isn't enabled on remote when needed, and

    update the remote store based on the destination path."""

    if 'lfs' in repo.requirements:

        # If the remote peer is for a local repo, the requirement tests in the

        # base class method enforce lfs support.  Otherwise, some revisions in

        # this repo use lfs, and the remote repo needs the extension loaded.

        if not remote.local() and not remote.capable('lfs'):

            # This is a copy of the message in exchange.push() when requirements

            # are missing between local repos.

            m = _("required features are not supported in the destination: %s")

            raise error.Abort(m % 'lfs',

                              hint=_('enable the lfs extension on the server'))

        # Repositories where this extension is disabled won't have the field.

        # But if there's a requirement, then the extension must be loaded AND

        # there may be blobs to push.

        remotestore = repo.svfs.lfsremoteblobstore

        try:

            repo.svfs.lfsremoteblobstore = blobstore.remote(repo, remote.url())

            return orig(repo, remote, *args, **kwargs)

        finally:

            repo.svfs.lfsremoteblobstore = remotestore

    else:

        return orig(repo, remote, *args, **kwargs)

# when writing a bundle via "hg bundle" command, upload related LFS blobs

@eh.wrapfunction(bundle2, 'writenewbundle')

def writenewbundle(orig, ui, repo, source, filename, bundletype, outgoing,

                   *args, **kwargs):

    """upload LFS blobs added by outgoing revisions on 'hg bundle'"""

    uploadblobsfromrevs(repo, outgoing.missing)

    return orig(ui, repo, source, filename, bundletype, outgoing, *args,

                **kwargs)

def extractpointers(repo, revs):

    """return a list of lfs pointers added by given revs"""

    repo.ui.debug('lfs: computing set of blobs to upload\n')

    pointers = {}

    makeprogress = repo.ui.makeprogress

    with makeprogress(_('lfs search'), _('changesets'), len(revs)) as progress:

        for r in revs:

            ctx = repo[r]

            for p in pointersfromctx(ctx).values():

                pointers[p.oid()] = p

            progress.increment()

        return sorted(pointers.values(), key=lambda p: p.oid())

def pointerfromctx(ctx, f, removed=False):

    """return a pointer for the named file from the given changectx, or None if

    the file isn't LFS.

    Optionally, the pointer for a file deleted from the context can be returned.

    Since no such pointer is actually stored, and to distinguish from a non LFS

    file, this pointer is represented by an empty dict.

    """

    _ctx = ctx

    if f not in ctx:

        if not removed:

            return None

        if f in ctx.p1():

            _ctx = ctx.p1()

        elif f in ctx.p2():

            _ctx = ctx.p2()