Synnefo

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from binascii import hexlify

from context_object import RadosObject, file_sync_read_chunks

from rados import *

CEPH_CONF_FILE="/etc/ceph/ceph.conf"

class RadosMapper(object):

    """Mapper.

       Required constructor parameters: mappath, namelen.

    """

    mappool = None

    namelen = None

    def __init__(self, **params):

        self.params = params

        self.namelen = params['namelen']

        mappool = params['mappool']

        rados = Rados(conffile=CEPH_CONF_FILE)

        rados.connect()

        if not rados.pool_exists(mappool):

            rados.pool_create(mappool)

        ioctx = rados.open_ioctx(mappool)

        self.mappool = mappool

        self.rados = rados

        self.ioctx = ioctx

    def _get_rear_map(self, maphash, create=0):

        name = hexlify(maphash)

        return RadosObject(name, self.ioctx, create)

    def _check_rear_map(self, maphash):

        name = hexlify(maphash)

        try:

            self.ioctx.stat(name)

            return True

        except ObjectNotFound:

            return False

    def map_retr(self, maphash, blkoff=0, nr=100000000000000):

        """Return as a list, part of the hashes map of an object

           at the given block offset.

           By default, return the whole hashes map.

        """

        namelen = self.namelen

        hashes = ()

        with self._get_rear_map(maphash, 0) as rmap:

            if rmap:

                hashes = list(rmap.sync_read_chunks(namelen, nr, blkoff))

        return hashes

    def map_stor(self, maphash, hashes=(), blkoff=0, create=1):

        """Store hashes in the given hashes map."""

        namelen = self.namelen

        if self._check_rear_map(maphash):

            return

        with self._get_rear_map(maphash, 1) as rmap:

            rmap.sync_write_chunks(namelen, blkoff, hashes, None)