# 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 i18n import _

import changelog, byterange, url, error, namespaces

import localrepo, manifest, util, scmutil, store

import urllib, urllib2, errno, os

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 seek(self, pos):

        self.pos = pos

    def read(self, bytes=None):

        req = urllib2.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()

            # Python 2.6+ defines a getcode() function, and 2.4 and

            # 2.5 appear to always have an undocumented code attribute

            # set. If we can't read either of those, fall back to 206

            # and hope for the best.

            code = getattr(f, 'getcode', lambda : getattr(f, 'code', 206))()

        except urllib2.HTTPError, inst:

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

            raise IOError(num, inst)

        except urllib2.URLError, 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

def build_opener(ui, authinfo):

    # urllib cannot handle URLs with embedded user or passwd

    urlopener = url.opener(ui, authinfo)

    urlopener.add_handler(byterange.HTTPRangeHandler())

    class statichttpvfs(scmutil.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, urllib.quote(path)))

            return httprangereader(f, urlopener)

        def join(self, path):

            if path:

                return os.path.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):

    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()

        opener = build_opener(ui, authinfo)

        self.opener = opener(self.path)

        self.vfs = self.opener

        self._phasedefaults = []

        self.names = namespaces.namespaces()

        try:

            requirements = scmutil.readrequires(self.vfs, self.supported)

        except IOError, 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, 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)

        # setup store

        self.store = store.store(requirements, self.path, opener)

        self.spath = self.store.path

        self.svfs = self.store.opener

        self.sopener = self.svfs

        self.sjoin = self.store.join

        self._filecache = {}

        self.requirements = requirements

        self.manifest = manifest.manifest(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

    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 lock(self, wait=True):

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

def instance(ui, path, create):

    if create:

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

    return statichttprepository(ui, path[7:])