view hgext/largefiles/proto.py @ 25912:cbbdd085c991

batching: migrate basic noop batching into peer.peer

"Real" batching only makes sense for wirepeers, but it greatly
simplifies the clients of peer instances if they can be ignorant to
actual batching capabilities of that peer. By moving the
not-really-batched batching code into peer.peer, all peer instances
now work with the batching API, thus simplifying users.

This leaves a couple of name forwards in wirepeer.py. Originally I had
planned to clean those up, but it kind of unclarifies other bits of
code that want to use batching, so I think it makes sense for the
names to stay exposed by wireproto. Specifically, almost nothing is
currently aware of peer (see largefiles.proto for an example), so
making them be aware of the peer module *and* the wireproto module
seems like some abstraction leakage. I *think* the right long-term fix
would actually be to make wireproto an implementation detail that
clients wouldn't need to know about, but I don't really know what that
would entail at the moment.

As far as I'm aware, no clients of batching in third-party extensions
will need updating, which is nice icing.

# Copyright 2011 Fog Creek Software
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.

import os
import urllib2
import re

from mercurial import error, httppeer, util, wireproto
from mercurial.i18n import _

import lfutil

LARGEFILES_REQUIRED_MSG = ('\nThis repository uses the largefiles extension.'
                           '\n\nPlease enable it in your Mercurial config '
                           'file.\n')

# these will all be replaced by largefiles.uisetup
capabilitiesorig = None
ssholdcallstream = None
httpoldcallstream = None

def putlfile(repo, proto, sha):
    '''Put a largefile into a repository's local store and into the
    user cache.'''
    proto.redirect()

    path = lfutil.storepath(repo, sha)
    util.makedirs(os.path.dirname(path))
    tmpfp = util.atomictempfile(path, createmode=repo.store.createmode)

    try:
        proto.getfile(tmpfp)
        tmpfp._fp.seek(0)
        if sha != lfutil.hexsha1(tmpfp._fp):
            raise IOError(0, _('largefile contents do not match hash'))
        tmpfp.close()
        lfutil.linktousercache(repo, sha)
    except IOError as e:
        repo.ui.warn(_('largefiles: failed to put %s into store: %s\n') %
                     (sha, e.strerror))
        return wireproto.pushres(1)
    finally:
        tmpfp.discard()

    return wireproto.pushres(0)

def getlfile(repo, proto, sha):
    '''Retrieve a largefile from the repository-local cache or system
    cache.'''
    filename = lfutil.findfile(repo, sha)
    if not filename:
        raise util.Abort(_('requested largefile %s not present in cache') % sha)
    f = open(filename, 'rb')
    length = os.fstat(f.fileno())[6]

    # Since we can't set an HTTP content-length header here, and
    # Mercurial core provides no way to give the length of a streamres
    # (and reading the entire file into RAM would be ill-advised), we
    # just send the length on the first line of the response, like the
    # ssh proto does for string responses.
    def generator():
        yield '%d\n' % length
        for chunk in util.filechunkiter(f):
            yield chunk
    return wireproto.streamres(generator())

def statlfile(repo, proto, sha):
    '''Return '2\n' if the largefile is missing, '0\n' if it seems to be in
    good condition.

    The value 1 is reserved for mismatched checksum, but that is too expensive
    to be verified on every stat and must be caught be running 'hg verify'
    server side.'''
    filename = lfutil.findfile(repo, sha)
    if not filename:
        return '2\n'
    return '0\n'

def wirereposetup(ui, repo):
    class lfileswirerepository(repo.__class__):
        def putlfile(self, sha, fd):
            # unfortunately, httprepository._callpush tries to convert its
            # input file-like into a bundle before sending it, so we can't use
            # it ...
            if issubclass(self.__class__, httppeer.httppeer):
                res = None
                try:
                    res = self._call('putlfile', data=fd, sha=sha,
                        headers={'content-type':'application/mercurial-0.1'})
                    d, output = res.split('\n', 1)
                    for l in output.splitlines(True):
                        self.ui.warn(_('remote: '), l) # assume l ends with \n
                    return int(d)
                except (ValueError, urllib2.HTTPError):
                    self.ui.warn(_('unexpected putlfile response: %r\n') % res)
                    return 1
            # ... but we can't use sshrepository._call because the data=
            # argument won't get sent, and _callpush does exactly what we want
            # in this case: send the data straight through
            else:
                try:
                    ret, output = self._callpush("putlfile", fd, sha=sha)
                    if ret == "":
                        raise error.ResponseError(_('putlfile failed:'),
                                output)
                    return int(ret)
                except IOError:
                    return 1
                except ValueError:
                    raise error.ResponseError(
                        _('putlfile failed (unexpected response):'), ret)

        def getlfile(self, sha):
            """returns an iterable with the chunks of the file with sha sha"""
            stream = self._callstream("getlfile", sha=sha)
            length = stream.readline()
            try:
                length = int(length)
            except ValueError:
                self._abort(error.ResponseError(_("unexpected response:"),
                                                length))

            # SSH streams will block if reading more than length
            for chunk in util.filechunkiter(stream, 128 * 1024, length):
                yield chunk
            # HTTP streams must hit the end to process the last empty
            # chunk of Chunked-Encoding so the connection can be reused.
            if issubclass(self.__class__, httppeer.httppeer):
                chunk = stream.read(1)
                if chunk:
                    self._abort(error.ResponseError(_("unexpected response:"),
                                                    chunk))

        @wireproto.batchable
        def statlfile(self, sha):
            f = wireproto.future()
            result = {'sha': sha}
            yield result, f
            try:
                yield int(f.value)
            except (ValueError, urllib2.HTTPError):
                # If the server returns anything but an integer followed by a
                # newline, newline, it's not speaking our language; if we get
                # an HTTP error, we can't be sure the largefile is present;
                # either way, consider it missing.
                yield 2

    repo.__class__ = lfileswirerepository

# advertise the largefiles=serve capability
def capabilities(repo, proto):
    return capabilitiesorig(repo, proto) + ' largefiles=serve'

def heads(repo, proto):
    if lfutil.islfilesrepo(repo):
        return wireproto.ooberror(LARGEFILES_REQUIRED_MSG)
    return wireproto.heads(repo, proto)

def sshrepocallstream(self, cmd, **args):
    if cmd == 'heads' and self.capable('largefiles'):
        cmd = 'lheads'
    if cmd == 'batch' and self.capable('largefiles'):
        args['cmds'] = args['cmds'].replace('heads ', 'lheads ')
    return ssholdcallstream(self, cmd, **args)

headsre = re.compile(r'(^|;)heads\b')

def httprepocallstream(self, cmd, **args):
    if cmd == 'heads' and self.capable('largefiles'):
        cmd = 'lheads'
    if cmd == 'batch' and self.capable('largefiles'):
        args['cmds'] = headsre.sub('lheads', args['cmds'])
    return httpoldcallstream(self, cmd, **args)