# fileserverclient.py - client for communicating with the cache process

#

# 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 hashlib

import io

import os

import threading

import time

import zlib

from mercurial.i18n import _

from mercurial.node import bin, hex, nullid

from mercurial import (

    error,

    node,

    pycompat,

    revlog,

    sshpeer,

    util,

    wireprotov1peer,

)

from mercurial.utils import procutil

from . import (

    constants,

    contentstore,

    metadatastore,

)

_sshv1peer = sshpeer.sshv1peer

# Statistics for debugging

fetchcost = 0

fetches = 0

fetched = 0

fetchmisses = 0

_lfsmod = None

def getcachekey(reponame, file, id):

    pathhash = node.hex(hashlib.sha1(file).digest())

    return os.path.join(reponame, pathhash[:2], pathhash[2:], id)

def getlocalkey(file, id):

    pathhash = node.hex(hashlib.sha1(file).digest())

    return os.path.join(pathhash, id)

def peersetup(ui, peer):

    class remotefilepeer(peer.__class__):

        @wireprotov1peer.batchable

        def x_rfl_getfile(self, file, node):

            if not self.capable(b'x_rfl_getfile'):

                raise error.Abort(

                    b'configured remotefile server does not support getfile'

                )

            f = wireprotov1peer.future()

            yield {b'file': file, b'node': node}, f

            code, data = f.value.split(b'\0', 1)

            if int(code):

                raise error.LookupError(file, node, data)

            yield data

        @wireprotov1peer.batchable

        def x_rfl_getflogheads(self, path):

            if not self.capable(b'x_rfl_getflogheads'):

                raise error.Abort(

                    b'configured remotefile server does not '

                    b'support getflogheads'

                )

            f = wireprotov1peer.future()

            yield {b'path': path}, f

            heads = f.value.split(b'\n') if f.value else []

            yield heads

        def _updatecallstreamopts(self, command, opts):

            if command != b'getbundle':

                return

            if (

                constants.NETWORK_CAP_LEGACY_SSH_GETFILES

                not in self.capabilities()

            ):

                return

                return

            if (

                constants.SHALLOWREPO_REQUIREMENT

                not in self._localrepo.requirements

            ):

                return

            bundlecaps = opts.get(b'bundlecaps')

            if bundlecaps:

                bundlecaps = [bundlecaps]

            else:

                bundlecaps = []

            # shallow, includepattern, and excludepattern are a hacky way of

            # carrying over data from the local repo to this getbundle

            # command. We need to do it this way because bundle1 getbundle

            # doesn't provide any other place we can hook in to manipulate

            # getbundle args before it goes across the wire. Once we get rid

            # of bundle1, we can use bundle2's _pullbundle2extraprepare to

            # do this more cleanly.

            bundlecaps.append(constants.BUNDLE2_CAPABLITY)

            if self._localrepo.includepattern:

                patterns = b'\0'.join(self._localrepo.includepattern)

                includecap = b"includepattern=" + patterns

                bundlecaps.append(includecap)

            if self._localrepo.excludepattern:

                patterns = b'\0'.join(self._localrepo.excludepattern)

                excludecap = b"excludepattern=" + patterns

                bundlecaps.append(excludecap)

            opts[b'bundlecaps'] = b','.join(bundlecaps)

        def _sendrequest(self, command, args, **opts):

            self._updatecallstreamopts(command, args)

            return super(remotefilepeer, self)._sendrequest(

                command, args, **opts

            )

        def _callstream(self, command, **opts):

            supertype = super(remotefilepeer, self)

                self._updatecallstreamopts(command, pycompat.byteskwargs(opts))

            return super(remotefilepeer, self)._callstream(command, **opts)

    peer.__class__ = remotefilepeer

class cacheconnection(object):

    """The connection for communicating with the remote cache. Performs

    gets and sets by communicating with an external process that has the

    cache-specific implementation.

    """

    def __init__(self):

        self.pipeo = self.pipei = self.pipee = None

        self.subprocess = None

        self.connected = False

    def connect(self, cachecommand):

        if self.pipeo:

            raise error.Abort(_(b"cache connection already open"))

        self.pipei, self.pipeo, self.pipee, self.subprocess = procutil.popen4(

            cachecommand

        )

        self.connected = True

    def close(self):

        def tryclose(pipe):

            try:

                pipe.close()

            except Exception:

                pass

        if self.connected:

            try:

                self.pipei.write(b"exit\n")

            except Exception:

                pass

            tryclose(self.pipei)

            self.pipei = None

            tryclose(self.pipeo)

            self.pipeo = None

            tryclose(self.pipee)

            self.pipee = None

            try:

                # Wait for process to terminate, making sure to avoid deadlock.

                # See https://docs.python.org/2/library/subprocess.html for

                # warnings about wait() and deadlocking.

                self.subprocess.communicate()

            except Exception:

                pass

            self.subprocess = None

        self.connected = False

    def request(self, request, flush=True):

        if self.connected:

            try:

                self.pipei.write(request)

                if flush:

                    self.pipei.flush()

            except IOError:

                self.close()

    def receiveline(self):

        if not self.connected:

            return None

        try:

            result = self.pipeo.readline()[:-1]

            if not result:

                self.close()

        except IOError:

            self.close()

        return result

def _getfilesbatch(

    remote, receivemissing, progresstick, missed, idmap, batchsize

):

    # Over http(s), iterbatch is a streamy method and we can start

    # looking at results early. This means we send one (potentially

    # large) request, but then we show nice progress as we process

    # file results, rather than showing chunks of $batchsize in

    # progress.

    #

    # Over ssh, iterbatch isn't streamy because batch() wasn't

    # explicitly designed as a streaming method. In the future we

    # should probably introduce a streambatch() method upstream and

    # use that for this.

    with remote.commandexecutor() as e:

        futures = []

        for m in missed:

            futures.append(

                e.callcommand(

                    b'x_rfl_getfile', {b'file': idmap[m], b'node': m[-40:]}

                )

            )

        for i, m in enumerate(missed):

            r = futures[i].result()

            futures[i] = None  # release memory

            file_ = idmap[m]

            node = m[-40:]

            receivemissing(io.BytesIO(b'%d\n%s' % (len(r), r)), file_, node)

            progresstick()

def _getfiles_optimistic(

    remote, receivemissing, progresstick, missed, idmap, step

):

    remote._callstream(b"x_rfl_getfiles")

    i = 0

    pipeo = remote._pipeo

    pipei = remote._pipei

    while i < len(missed):

        # issue a batch of requests

        start = i

        end = min(len(missed), start + step)

        i = end

        for missingid in missed[start:end]:

            # issue new request

            versionid = missingid[-40:]

            file = idmap[missingid]

            sshrequest = b"%s%s\n" % (versionid, file)

            pipeo.write(sshrequest)

        pipeo.flush()

        # receive batch results

        for missingid in missed[start:end]:

            versionid = missingid[-40:]

            file = idmap[missingid]

            receivemissing(pipei, file, versionid)

            progresstick()

    # End the command

    pipeo.write(b'\n')

    pipeo.flush()

def _getfiles_threaded(

    remote, receivemissing, progresstick, missed, idmap, step

):

    remote._callstream(b"getfiles")

    pipeo = remote._pipeo

    pipei = remote._pipei

    def writer():

        for missingid in missed:

            versionid = missingid[-40:]

            file = idmap[missingid]

            sshrequest = b"%s%s\n" % (versionid, file)

            pipeo.write(sshrequest)

        pipeo.flush()

    writerthread = threading.Thread(target=writer)

    writerthread.daemon = True

    writerthread.start()

    for missingid in missed:

        versionid = missingid[-40:]

        file = idmap[missingid]

        receivemissing(pipei, file, versionid)

        progresstick()

    writerthread.join()

    # End the command

    pipeo.write(b'\n')

    pipeo.flush()

class fileserverclient(object):

    """A client for requesting files from the remote file server.

    """

    def __init__(self, repo):

        ui = repo.ui

        self.repo = repo

        self.ui = ui

        self.cacheprocess = ui.config(b"remotefilelog", b"cacheprocess")

        if self.cacheprocess:

            self.cacheprocess = util.expandpath(self.cacheprocess)

        # This option causes remotefilelog to pass the full file path to the

        # cacheprocess instead of a hashed key.

        self.cacheprocesspasspath = ui.configbool(

            b"remotefilelog", b"cacheprocess.includepath"

        )

        self.debugoutput = ui.configbool(b"remotefilelog", b"debug")

        self.remotecache = cacheconnection()

    def setstore(self, datastore, historystore, writedata, writehistory):

        self.datastore = datastore

        self.historystore = historystore

        self.writedata = writedata

        self.writehistory = writehistory

    def _connect(self):

        return self.repo.connectionpool.get(self.repo.fallbackpath)

    def request(self, fileids):

        """Takes a list of filename/node pairs and fetches them from the

        server. Files are stored in the local cache.

        A list of nodes that the server couldn't find is returned.

        If the connection fails, an exception is raised.

        """

        if not self.remotecache.connected:

            self.connect()

        cache = self.remotecache

        writedata = self.writedata

        repo = self.repo

        total = len(fileids)

        request = b"get\n%d\n" % total

        idmap = {}

        reponame = repo.name

        for file, id in fileids:

            fullid = getcachekey(reponame, file, id)

            if self.cacheprocesspasspath:

                request += file + b'\0'

            request += fullid + b"\n"

            idmap[fullid] = file

        cache.request(request)

        progress = self.ui.makeprogress(_(b'downloading'), total=total)

        progress.update(0)

        missed = []

        while True:

            missingid = cache.receiveline()

            if not missingid:

                missedset = set(missed)

                for missingid in idmap:

                    if not missingid in missedset:

                        missed.append(missingid)

                self.ui.warn(

                    _(

                        b"warning: cache connection closed early - "

                        + b"falling back to server\n"

                    )

                )

                break

            if missingid == b"0":

                break

            if missingid.startswith(b"_hits_"):

                # receive progress reports

                parts = missingid.split(b"_")

                progress.increment(int(parts[2]))

                continue

            missed.append(missingid)

        global fetchmisses

        fetchmisses += len(missed)

        fromcache = total - len(missed)

        progress.update(fromcache, total=total)

        self.ui.log(

            b"remotefilelog",

            b"remote cache hit rate is %r of %r\n",

            fromcache,

            total,

            hit=fromcache,

            total=total,