# 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

import localrepo, manifest, util, store

import urllib, urllib2, errno

class httprangereader(object):

    def __init__(self, url, opener):

        # we assume opener has HTTPRangeHandler

        self.url = url

        self.pos = 0

        self.opener = opener

    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

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

        try:

            f = self.opener.open(req)

            data = f.read()

            if hasattr(f, 'getcode'):

                # python 2.6+

                code = f.getcode()

            elif hasattr(f, 'code'):

                # undocumented attribute, seems to be set in 2.4 and 2.5

                code = f.code

            else:

                # Don't know how to check, hope for the best.

                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 build_opener(ui, authinfo):

    # urllib cannot handle URLs with embedded user or passwd

    urlopener = url.opener(ui, authinfo)

    urlopener.add_handler(byterange.HTTPRangeHandler())

    def opener(base):

        """return a function that opens files over http"""

        p = base

        def o(path, mode="r"):

            f = "/".join((p, urllib.quote(path)))

            return httprangereader(f, urlopener)

        return o

    return opener

class statichttprepository(localrepo.localrepository):

    def __init__(self, ui, path):

        self._url = path

        self.ui = ui

        self.path, authinfo = url.getauthinfo(path.rstrip('/') + "/.hg")

        opener = build_opener(ui, authinfo)

        self.opener = opener(self.path)

        # find requirements

        try:

            requirements = self.opener("requires").read().splitlines()

        except IOError, inst:

            if inst.errno != errno.ENOENT:

                raise

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

            try:

                self.opener("00changelog.i").read(1)

            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)

            requirements = []

        # check them

        for r in requirements:

            if r not in self.supported:

                raise error.RepoError(_("requirement '%s' not supported") % r)

        # setup store

        def pjoin(a, b):

            return a + '/' + b

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

        self.spath = self.store.path

        self.sopener = self.store.opener

        self.sjoin = self.store.join

        self.manifest = manifest.manifest(self.sopener)

        self.changelog = changelog.changelog(self.sopener)

        self._tags = None

        self.nodetagscache = None

        self.encodepats = None

        self.decodepats = None

    def url(self):

        return self._url

    def local(self):

        return False

    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:])