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#

#

# Copyright (C) 2010 Google Inc.

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful, but

# WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

# General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA

# 02110-1301, USA.

"""Module implementing the parameter types code."""

from ganeti import compat

# Modifiable default values; need to define these here before the

# actual LUs

def EmptyList():

  """Returns an empty list.

  """

  return []

def EmptyDict():

  """Returns an empty dict.

  """

  return {}

#: The without-default default value

NoDefault = object()

#: The no-type (value to complex to check it in the type system)

NoType = object()

# Some basic types

def TNotNone(val):

  """Checks if the given value is not None.

  """

  return val is not None

def TNone(val):

  """Checks if the given value is None.

  """

  return val is None

def TBool(val):

  """Checks if the given value is a boolean.

  """

  return isinstance(val, bool)

def TInt(val):

  """Checks if the given value is an integer.

  """

  # For backwards compatibility with older Python versions, boolean values are

  # also integers and should be excluded in this test.

  #

  # >>> (isinstance(False, int), isinstance(True, int))

  # (True, True)

  return isinstance(val, int) and not isinstance(val, bool)

def TFloat(val):

  """Checks if the given value is a float.

  """

  return isinstance(val, float)

def TString(val):

  """Checks if the given value is a string.

  """

  return isinstance(val, basestring)

def TTrue(val):

  """Checks if a given value evaluates to a boolean True value.

  """

  return bool(val)

def TElemOf(target_list):

  """Builds a function that checks if a given value is a member of a list.

  """

  return lambda val: val in target_list

# Container types

def TList(val):

  """Checks if the given value is a list.

  """

  return isinstance(val, list)

def TDict(val):

  """Checks if the given value is a dictionary.

  """

  return isinstance(val, dict)

def TIsLength(size):

  """Check is the given container is of the given size.

  """

  return lambda container: len(container) == size

# Combinator types

def TAnd(*args):

  """Combine multiple functions using an AND operation.

  """

  def fn(val):

    return compat.all(t(val) for t in args)

  return fn

def TOr(*args):

  """Combine multiple functions using an AND operation.

  """

  def fn(val):

    return compat.any(t(val) for t in args)

  return fn

def TMap(fn, test):

  """Checks that a modified version of the argument passes the given test.

  """

  return lambda val: test(fn(val))

# Type aliases

#: a non-empty string

TNonEmptyString = TAnd(TString, TTrue)

#: a maybe non-empty string

TMaybeString = TOr(TNonEmptyString, TNone)

#: a maybe boolean (bool or none)

TMaybeBool = TOr(TBool, TNone)

#: a positive integer

TPositiveInt = TAnd(TInt, lambda v: v >= 0)

#: a strictly positive integer

TStrictPositiveInt = TAnd(TInt, lambda v: v > 0)

def TListOf(my_type):

  """Checks if a given value is a list with all elements of the same type.

  """

  return TAnd(TList,

               lambda lst: compat.all(my_type(v) for v in lst))

def TDictOf(key_type, val_type):

  """Checks a dict type for the type of its key/values.

  """

  return TAnd(TDict,

              lambda my_dict: (compat.all(key_type(v) for v in my_dict.keys())

                               and compat.all(val_type(v)

                                              for v in my_dict.values())))