# statichttprepo.py - simple http repository class for mercurial

#

# This provides read-only repo access to repositories exported via static http

#

# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>

#

# 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

from .i18n import _

from . import (

    changelog,

    error,

    localrepo,

    manifest,

    namespaces,

    pathutil,

    url,

    util,

    vfs as vfsmod,

)

urlerr = util.urlerr

urlreq = util.urlreq

class httprangereader(object):

    def __init__(self, url, opener):

        # we assume opener has HTTPRangeHandler

        self.url = url

        self.pos = 0

        self.opener = opener

        self.name = url

    def __enter__(self):

        return self

    def __exit__(self, exc_type, exc_value, traceback):

        self.close()

    def seek(self, pos):

        self.pos = pos

    def read(self, bytes=None):

        req = urlreq.request(self.url)

        end = ''

        if bytes:

            end = self.pos + bytes - 1

        if self.pos or end:

            req.add_header('Range', 'bytes=%d-%s' % (self.pos, end))

        try:

            f = self.opener.open(req)

            data = f.read()

            code = f.code

        except urlerr.httperror as inst:

            num = inst.code == 404 and errno.ENOENT or None

            raise IOError(num, inst)

        except urlerr.urlerror as inst:

            raise IOError(None, inst.reason[1])

        if code == 200:

            # HTTPRangeHandler does nothing if remote does not support

            # Range headers and returns the full entity. Let's slice it.

            if bytes:

                data = data[self.pos:self.pos + bytes]

            else:

                data = data[self.pos:]

        elif bytes:

            data = data[:bytes]

        self.pos += len(data)

        return data

    def readlines(self):

        return self.read().splitlines(True)

    def __iter__(self):

        return iter(self.readlines())

    def close(self):

        pass

# _RangeError and _HTTPRangeHandler were originally in byterange.py,

# which was itself extracted from urlgrabber. See the last version of

# byterange.py from history if you need more information.

class _RangeError(IOError):

    """Error raised when an unsatisfiable range is requested."""

class _HTTPRangeHandler(urlreq.basehandler):

    """Handler that enables HTTP Range headers.

    This was extremely simple. The Range header is a HTTP feature to

    begin with so all this class does is tell urllib2 that the

    "206 Partial Content" response from the HTTP server is what we

    expected.

    """

    def http_error_206(self, req, fp, code, msg, hdrs):

        # 206 Partial Content Response

        r = urlreq.addinfourl(fp, hdrs, req.get_full_url())

        r.code = code

        r.msg = msg

        return r

    def http_error_416(self, req, fp, code, msg, hdrs):

        # HTTP's Range Not Satisfiable error

        raise _RangeError('Requested Range Not Satisfiable')

def build_opener(ui, authinfo):

    # urllib cannot handle URLs with embedded user or passwd

    urlopener = url.opener(ui, authinfo)

    urlopener.add_handler(_HTTPRangeHandler())

    class statichttpvfs(vfsmod.abstractvfs):

        def __init__(self, base):

            self.base = base

        def __call__(self, path, mode='r', *args, **kw):

            if mode not in ('r', 'rb'):

                raise IOError('Permission denied')

            f = "/".join((self.base, urlreq.quote(path)))

            return httprangereader(f, urlopener)

        def join(self, path):

            if path:

                return pathutil.join(self.base, path)

            else:

                return self.base

    return statichttpvfs

class statichttppeer(localrepo.localpeer):

    def local(self):

        return None

    def canpush(self):

        return False

class statichttprepository(localrepo.localrepository,

                           localrepo.revlogfilestorage):

    supported = localrepo.localrepository._basesupported

    def __init__(self, ui, path):

        self._url = path

        self.ui = ui

        self.root = path

        u = util.url(path.rstrip('/') + "/.hg")

        self.path, authinfo = u.authinfo()

        vfsclass = build_opener(ui, authinfo)

        self.vfs = vfsclass(self.path)

        self.cachevfs = vfsclass(self.vfs.join('cache'))

        self._phasedefaults = []

        self.names = namespaces.namespaces()

        self.filtername = None

        try:

            requirements = set(self.vfs.read(b'requires').splitlines())

        except IOError as inst:

            if inst.errno != errno.ENOENT:

                raise

            requirements = set()

            # check if it is a non-empty old-style repository

            try:

                fp = self.vfs("00changelog.i")

                fp.read(1)

                fp.close()

            except IOError as inst:

                if inst.errno != errno.ENOENT:

                    raise

                # we do not care about empty old-style repositories here

                msg = _("'%s' does not appear to be an hg repository") % path

                raise error.RepoError(msg)

        supportedrequirements = localrepo.gathersupportedrequirements(ui)

        localrepo.ensurerequirementsrecognized(requirements,

                                               supportedrequirements)

        localrepo.ensurerequirementscompatible(ui, requirements)

        # setup store

        self.store = localrepo.makestore(requirements, self.path, vfsclass)

        self.spath = self.store.path

        self.svfs = self.store.opener

        self.sjoin = self.store.join

        self._filecache = {}

        self.requirements = requirements

        rootmanifest = manifest.manifestrevlog(self.svfs)

        self.changelog = changelog.changelog(self.svfs)

        self._tags = None

        self.nodetagscache = None

        self._branchcaches = {}

        self._revbranchcache = None

        self.encodepats = None

        self.decodepats = None

        self._transref = None

    def _restrictcapabilities(self, caps):

        caps = super(statichttprepository, self)._restrictcapabilities(caps)

        return caps.difference(["pushkey"])

    def url(self):

        return self._url

    def local(self):

        return False

    def peer(self):

        return statichttppeer(self)

    def wlock(self, wait=True):

        raise error.LockUnavailable(0, _('lock not available'), 'lock',

                                    _('cannot lock static-http repository'))

    def lock(self, wait=True):

        raise error.Abort(_('cannot lock static-http repository'))

    def _writecaches(self):

        pass # statichttprepository are read only

def instance(ui, path, create, intents=None, createopts=None):

    if create:

        raise error.Abort(_('cannot create new static-http repository'))

    return statichttprepository(ui, path[7:])