AttrHelper.py

############################################################################
# This file is part of LImA, a Library for Image Acquisition
#
# Copyright (C) : 2009-2012
# European Synchrotron Radiation Facility
# BP 220, Grenoble 38043
# FRANCE
#
# This 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 3 of the License, or
# (at your option) any later version.
#
# This software 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, see <http://www.gnu.org/licenses/>.
############################################################################


#============================================================================
#                              HELPERS  
#============================================================================
#
# These helpers allows any one to map attributes with the LIMA interfaces commands without having
# to write any extra code for the read_ / write_ methods.
# It works for attributes with enumerate value and for simple value passing.
# Mapping between attributes and commands is done using a dictionnary and for each
# attribute with enum an extra dictionnary is mandatory. e.g for Andor camera we could have:
#         self.__FastTrigger = {'ON':True,
#                           'OFF':False}
#        self.__Cooler = {'ON': True,
#                             'OFF': False}
#        self.__ShutterLevel = {'LOW':0,
#                                   'HIGH':1}       
#        self.__Attribute2FunctionBase = {'fast_trigger': 'FastExtTrigger',
#                                         'shutter_level': 'ShutterLevel',
#                                         'temperature': 'Temperature',
#                                         'temperature_sp': 'TemperatureSP',
#                                         'cooler': 'Cooler',
#                                         'cooling_status': 'CoolingStatus',
#                                         }
# __Attribute2FunctionBase dict. maps attributes and commands (e.g. fast_trigger --> setFastExtTrigger and getFastExtTrigger)
# __FasTrigger dict. is the enum list for the attribute fast_trigger. Naming convention supposes the attribute name composed
# with words separated by "_" and the enum dictionnary name is composed with the same words titled.
#
# Finally you will need to overload your __getattr__ class method and to call the help function get_attr_4u e.g:
#
# def __getattr__(self, name):
#       return get_attr_4u(self, name, _AndorCamera)
#


import PyTango

def _getDictKey(dict, value):
    try:
        ind = dict.values().index(value)                            
    except ValueError:
        return None
    return dict.keys()[ind]

def _getDictValue(dict, key):
    try:
        value = dict[key.upper()]
    except KeyError:
        return None
    return value

## @brief Class for genenic read_<attribute> with enum value
class CallableReadEnum:
    def __init__(self,dictionnary,func2Call) :
        self.__dict = dictionnary
        self.__func2Call = func2Call

    def __call__(self,attr) :
        value = _getDictKey(self.__dict,self.__func2Call())
        attr.set_value(value)

## @brief Class for genenic write_<attribute> with enum value
class CallableWriteEnum:
    def __init__(self,attr_name,dictionnary,func2Call) :
        self.__attr_name = attr_name
        self.__dict = dictionnary
        self.__func2Call = func2Call
        
    def __call__(self,attr) :
        data = attr.get_write_value()
        value = _getDictValue(self.__dict,data.upper())
        if value is None:
            PyTango.Except.throw_exception('WrongData',\
                                           'Wrong value %s: %s'%(self.__attr_name,data.upper()),\
                                           'LimaCCD Class')
        else:
            self.__func2Call(value)
   
## @brief Class for genenic read_<attribute> with simple value
class CallableRead:
    def __init__(self,func2Call) :        
        self.__func2Call = func2Call

    def __call__(self,attr) :
        value = self.__func2Call()
        attr.set_value(value)

## @brief Class for genenic write_<attribute> with simple value
class CallableWrite:
    def __init__(self,attr_name,func2Call) :
        self.__attr_name = attr_name
        self.__func2Call = func2Call
        
    def __call__(self,attr) :
        value = attr.get_write_value()
        if value is None:
            PyTango.Except.throw_exception('WrongData',\
                                           'Wrong value %s: %s'%(self.__attr_name,data.upper()),\
                                           'LimaCCD Class')
        else:
            self.__func2Call(value)

## @brief helper for automatic attribute to command mapping
# To be called from __getattr__
def get_attr_4u(obj,name,interface) :

    if name.startswith('read_') or name.startswith('write_') :
        split_name = name.split('_')[1:]
        attr_name = ''.join([x.title() for x in split_name])
        dict_name = '_' + obj.__class__.__name__ + '__' + attr_name
        d = getattr(obj,dict_name,None)
        dict_name = '_' + obj.__class__.__name__ + '__Attribute2FunctionBase'
        dict_name = getattr(obj,dict_name,None)
        if dict_name:
            attr_name = dict_name.get('_'.join(split_name),attr_name)
        
        if d:
            if name.startswith('read_') :
                functionName = 'get' + attr_name
                function2Call = getattr(interface,functionName)
                callable_obj = CallableReadEnum(d,function2Call)
            else:
                functionName = 'set' + attr_name
                function2Call = getattr(interface,functionName)
                callable_obj = CallableWriteEnum('_'.join(split_name),
                                                     d,function2Call)

        else:
            if name.startswith('read_') :
                functionName = 'get' + attr_name
                function2Call = getattr(interface,functionName)
                callable_obj = CallableRead(function2Call)
            else:
                functionName = 'set' + attr_name
                function2Call = getattr(interface,functionName)
                callable_obj = CallableWrite('_'.join(split_name),
                                                     function2Call)
                
        obj.__dict__[name] = callable_obj
        return callable_obj

    raise AttributeError('%s has no attribute %s' % (obj.__class__.__name__,name))

## @brief return list of posible value for attribute name
def get_attr_string_value_list(obj, attr_name):
    valueList = []
    dict_name = '_' + obj.__class__.__name__ + '__' + ''.join([x.title() for x in attr_name.split('_')])
    d = getattr(obj,dict_name,None)
    if d:
        valueList = d.keys()
    return valueList