# remotefilelogserver.py - server logic for a remotefilelog server

#

# Copyright 2013 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 errno

import os

import stat

import time

import zlib

from mercurial.i18n import _

from mercurial.node import bin, hex, nullid

from mercurial.pycompat import open

from mercurial import (

    changegroup,

    changelog,

    context,

    error,

    extensions,

    match,

    pycompat,

    store,

    streamclone,

    util,

    wireprotoserver,

    wireprototypes,

    wireprotov1server,

)

from . import (

    constants,

    shallowutil,

)

_sshv1server = wireprotoserver.sshv1protocolhandler

def setupserver(ui, repo):

    """Sets up a normal Mercurial repo so it can serve files to shallow repos.

    """

    onetimesetup(ui)

    # don't send files to shallow clients during pulls

    def generatefiles(

        orig, self, changedfiles, linknodes, commonrevs, source, *args, **kwargs

    ):

        caps = self._bundlecaps or []

        if constants.BUNDLE2_CAPABLITY in caps:

            # only send files that don't match the specified patterns

            includepattern = None

            excludepattern = None

            for cap in self._bundlecaps or []:

                if cap.startswith(b"includepattern="):

                    includepattern = cap[len(b"includepattern=") :].split(b'\0')

                elif cap.startswith(b"excludepattern="):

                    excludepattern = cap[len(b"excludepattern=") :].split(b'\0')

            m = match.always()

            if includepattern or excludepattern:

                m = match.match(

                    repo.root, b'', None, includepattern, excludepattern

                )

            changedfiles = list([f for f in changedfiles if not m(f)])

        return orig(

            self, changedfiles, linknodes, commonrevs, source, *args, **kwargs

        )

    extensions.wrapfunction(

        changegroup.cgpacker, b'generatefiles', generatefiles

    )

onetime = False

def onetimesetup(ui):

    """Configures the wireprotocol for both clients and servers.

    """

    global onetime

    if onetime:

        return

    onetime = True

    # support file content requests

    wireprotov1server.wireprotocommand(

        b'x_rfl_getflogheads', b'path', permission=b'pull'

    )(getflogheads)

    wireprotov1server.wireprotocommand(

        b'x_rfl_getfiles', b'', permission=b'pull'

    )(getfiles)

    wireprotov1server.wireprotocommand(

        b'x_rfl_getfile', b'file node', permission=b'pull'

    )(getfile)

    class streamstate(object):

        match = None

        shallowremote = False

        noflatmf = False

    state = streamstate()

    def stream_out_shallow(repo, proto, other):

        includepattern = None

        excludepattern = None

        raw = other.get(b'includepattern')

        if raw:

            includepattern = raw.split(b'\0')

        raw = other.get(b'excludepattern')

        if raw:

            excludepattern = raw.split(b'\0')

        oldshallow = state.shallowremote

        oldmatch = state.match

        oldnoflatmf = state.noflatmf

        try:

            state.shallowremote = True

            state.match = match.always()

            state.noflatmf = other.get(b'noflatmanifest') == b'True'

            if includepattern or excludepattern:

                state.match = match.match(

                    repo.root, b'', None, includepattern, excludepattern

                )

            streamres = wireprotov1server.stream(repo, proto)

            # Force the first value to execute, so the file list is computed

            # within the try/finally scope

            first = next(streamres.gen)

            second = next(streamres.gen)

            def gen():

                yield first

                yield second

                for value in streamres.gen:

                    yield value

            return wireprototypes.streamres(gen())

        finally:

            state.shallowremote = oldshallow

            state.match = oldmatch

            state.noflatmf = oldnoflatmf

    wireprotov1server.commands[b'stream_out_shallow'] = (

        stream_out_shallow,

        b'*',

    )

    # don't clone filelogs to shallow clients

    def _walkstreamfiles(orig, repo, matcher=None):

        if state.shallowremote:

            # if we are shallow ourselves, stream our local commits

            if shallowutil.isenabled(repo):

                striplen = len(repo.store.path) + 1

                readdir = repo.store.rawvfs.readdir

                visit = [os.path.join(repo.store.path, b'data')]

                while visit:

                    p = visit.pop()

                    for f, kind, st in readdir(p, stat=True):

                        fp = p + b'/' + f

                        if kind == stat.S_IFREG:

                            if not fp.endswith(b'.i') and not fp.endswith(

                                b'.d'

                            ):

                                n = util.pconvert(fp[striplen:])

                                yield (store.decodedir(n), n, st.st_size)

                        if kind == stat.S_IFDIR:

                            visit.append(fp)

                for (u, e, s) in repo.store.datafiles():

                    if u.startswith(b'meta/') and (

                        u.endswith(b'.i') or u.endswith(b'.d')

                    ):

                        yield (u, e, s)

            # Return .d and .i files that do not match the shallow pattern

            match = state.match

            if match and not match.always():

                for (u, e, s) in repo.store.datafiles():

                    f = u[5:-2]  # trim data/...  and .i/.d

                    if not state.match(f):

                        yield (u, e, s)

            for x in repo.store.topfiles():

                if state.noflatmf and x[0][:11] == b'00manifest.':

                    continue

                yield x

        elif shallowutil.isenabled(repo):

            # don't allow cloning from a shallow repo to a full repo

            # since it would require fetching every version of every

            # file in order to create the revlogs.

            raise error.Abort(

                _(b"Cannot clone from a shallow repo to a full repo.")

            )

        else:

            for x in orig(repo, matcher):

                yield x

    extensions.wrapfunction(streamclone, b'_walkstreamfiles', _walkstreamfiles)

    # expose remotefilelog capabilities

    def _capabilities(orig, repo, proto):

        caps = orig(repo, proto)

        if shallowutil.isenabled(repo) or ui.configbool(

            b'remotefilelog', b'server'

        ):

            if isinstance(proto, _sshv1server):

                # legacy getfiles method which only works over ssh

                caps.append(constants.NETWORK_CAP_LEGACY_SSH_GETFILES)

            caps.append(b'x_rfl_getflogheads')

            caps.append(b'x_rfl_getfile')

        return caps

    extensions.wrapfunction(wireprotov1server, b'_capabilities', _capabilities)

    def _adjustlinkrev(orig, self, *args, **kwargs):

        # When generating file blobs, taking the real path is too slow on large

        # repos, so force it to just return the linkrev directly.

        repo = self._repo

        if util.safehasattr(repo, b'forcelinkrev') and repo.forcelinkrev:

            return self._filelog.linkrev(self._filelog.rev(self._filenode))

        return orig(self, *args, **kwargs)

    extensions.wrapfunction(

        context.basefilectx, b'_adjustlinkrev', _adjustlinkrev

    )

    def _iscmd(orig, cmd):

        if cmd == b'x_rfl_getfiles':

            return False

        return orig(cmd)

    extensions.wrapfunction(wireprotoserver, b'iscmd', _iscmd)

def _loadfileblob(repo, cachepath, path, node):

    filecachepath = os.path.join(cachepath, path, hex(node))

    if not os.path.exists(filecachepath) or os.path.getsize(filecachepath) == 0:

        filectx = repo.filectx(path, fileid=node)

        if filectx.node() == nullid:

            repo.changelog = changelog.changelog(repo.svfs)

            filectx = repo.filectx(path, fileid=node)

        text = createfileblob(filectx)

        # TODO configurable compression engines

        text = zlib.compress(text)

        # everything should be user & group read/writable

        oldumask = os.umask(0o002)

        try:

            dirname = os.path.dirname(filecachepath)

            if not os.path.exists(dirname):

                try:

                    os.makedirs(dirname)

                except OSError as ex:

                    if ex.errno != errno.EEXIST:

                        raise

            f = None

            try:

                f = util.atomictempfile(filecachepath, b"wb")

                f.write(text)

            except (IOError, OSError):

                # Don't abort if the user only has permission to read,

                # and not write.

                pass

            finally:

                if f:

                    f.close()

        finally:

            os.umask(oldumask)

    else:

        with open(filecachepath, b"rb") as f:

            text = f.read()

    return text

def getflogheads(repo, proto, path):

    """A server api for requesting a filelog's heads

    """

    flog = repo.file(path)

    heads = flog.heads()

    return b'\n'.join((hex(head) for head in heads if head != nullid))

def getfile(repo, proto, file, node):

    """A server api for requesting a particular version of a file. Can be used

    in batches to request many files at once. The return protocol is:

    <errorcode>\0<data/errormsg> where <errorcode> is 0 for success or

    non-zero for an error.

    data is a compressed blob with revlog flag and ancestors information. See

    createfileblob for its content.

    """

    if shallowutil.isenabled(repo):

        return b'1\0' + _(b'cannot fetch remote files from shallow repo')

    cachepath = repo.ui.config(b"remotefilelog", b"servercachepath")

    if not cachepath:

        cachepath = os.path.join(repo.path, b"remotefilelogcache")

    node = bin(node.strip())

    if node == nullid:

        return b'0\0'

    return b'0\0' + _loadfileblob(repo, cachepath, file, node)

def getfiles(repo, proto):

    """A server api for requesting particular versions of particular files.

    """

    if shallowutil.isenabled(repo):

        raise error.Abort(_(b'cannot fetch remote files from shallow repo'))

    if not isinstance(proto, _sshv1server):

        raise error.Abort(_(b'cannot fetch remote files over non-ssh protocol'))

    def streamer():

        fin = proto._fin

        cachepath = repo.ui.config(b"remotefilelog", b"servercachepath")

        if not cachepath:

            cachepath = os.path.join(repo.path, b"remotefilelogcache")

        while True:

            request = fin.readline()[:-1]

            if not request:

                break

            node = bin(request[:40])

            if node == nullid:

                yield b'0\n'

                continue

            path = request[40:]

            text = _loadfileblob(repo, cachepath, path, node)

            yield b'%d\n%s' % (len(text), text)

            # it would be better to only flush after processing a whole batch

            # but currently we don't know if there are more requests coming

            proto._fout.flush()

    return wireprototypes.streamres(streamer())

def createfileblob(filectx):

    """

    format:

        v0:

            str(len(rawtext)) + '\0' + rawtext + ancestortext

        v1:

            'v1' + '\n' + metalist + '\0' + rawtext + ancestortext

            metalist := metalist + '\n' + meta | meta

            meta := sizemeta | flagmeta

            sizemeta := METAKEYSIZE + str(len(rawtext))

            flagmeta := METAKEYFLAG + str(flag)

            note: sizemeta must exist. METAKEYFLAG and METAKEYSIZE must have a

            length of 1.

    """

    flog = filectx.filelog()

    frev = filectx.filerev()

    revlogflags = flog._revlog.flags(frev)

    if revlogflags == 0:

        # normal files

        text = filectx.data()

    else:

        # lfs, read raw revision data

        text = flog.rawdata(frev)

    repo = filectx._repo

    ancestors = [filectx]

    try:

        repo.forcelinkrev = True

        ancestors.extend([f for f in filectx.ancestors()])

        ancestortext = b""

        for ancestorctx in ancestors:

            parents = ancestorctx.parents()

            p1 = nullid

            p2 = nullid

            if len(parents) > 0:

                p1 = parents[0].filenode()

            if len(parents) > 1:

                p2 = parents[1].filenode()