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# General Public License for more details.

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"""Logical units for queries."""

from ganeti import constants

from ganeti import errors

from ganeti import query

from ganeti.cmdlib.backup import ExportQuery

from ganeti.cmdlib.base import NoHooksLU

from ganeti.cmdlib.cluster import ClusterQuery

from ganeti.cmdlib.group import GroupQuery

from ganeti.cmdlib.instance_query import InstanceQuery

from ganeti.cmdlib.misc import ExtStorageQuery

from ganeti.cmdlib.operating_system import OsQuery

#: Query type implementations

_QUERY_IMPL = {

  constants.QR_CLUSTER: ClusterQuery,

  constants.QR_INSTANCE: InstanceQuery,

  constants.QR_GROUP: GroupQuery,

  constants.QR_OS: OsQuery,

  constants.QR_EXTSTORAGE: ExtStorageQuery,

  constants.QR_EXPORT: ExportQuery,

  }

assert set(_QUERY_IMPL.keys()) == constants.QR_VIA_OP

def _GetQueryImplementation(name):

  """Returns the implementation for a query type.

  @param name: Query type, must be one of L{constants.QR_VIA_OP}

  """

  try:

    return _QUERY_IMPL[name]

  except KeyError:

    raise errors.OpPrereqError("Unknown query resource '%s'" % name,

                               errors.ECODE_INVAL)

class LUQuery(NoHooksLU):

  """Query for resources/items of a certain kind.

  """

  # pylint: disable=W0142

  REQ_BGL = False

  def CheckArguments(self):

    qcls = _GetQueryImplementation(self.op.what)

    self.impl = qcls(self.op.qfilter, self.op.fields, self.op.use_locking)

  def ExpandNames(self):

    self.impl.ExpandNames(self)

  def DeclareLocks(self, level):

    self.impl.DeclareLocks(self, level)

  def Exec(self, feedback_fn):

    return self.impl.NewStyleQuery(self)

class LUQueryFields(NoHooksLU):

  """Query for resources/items of a certain kind.

  """

  # pylint: disable=W0142

  REQ_BGL = False

  def CheckArguments(self):

    self.qcls = _GetQueryImplementation(self.op.what)

  def ExpandNames(self):

    self.needed_locks = {}

  def Exec(self, feedback_fn):

    return query.QueryFields(self.qcls.FIELDS, self.op.fields)