add features
+ split out metaclass and params Change-Id: I4d9092827cd74da6757ef1f30d2460471e5e5ef3 Reviewed-on: https://forge.frm2.tum.de/review/18190 Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de> Reviewed-by: Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
This commit is contained in:
Enrico Faulhaber
176
secop/metaclass.py
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176
secop/metaclass.py
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# -*- coding: utf-8 -*-
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# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Enrico Faulhaber <enrico.faulhaber@frm2.tum.de>
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#
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# *****************************************************************************
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"""Define Metaclass for Modules/Features"""
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from __future__ import print_function
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try:
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# pylint: disable=unused-import
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from six import add_metaclass # for py2/3 compat
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except ImportError:
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# copied from six v1.10.0
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def add_metaclass(metaclass):
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"""Class decorator for creating a class with a metaclass."""
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def wrapper(cls):
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orig_vars = cls.__dict__.copy()
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slots = orig_vars.get('__slots__')
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if slots is not None:
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if isinstance(slots, str):
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slots = [slots]
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for slots_var in slots:
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orig_vars.pop(slots_var)
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orig_vars.pop('__dict__', None)
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orig_vars.pop('__weakref__', None)
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return metaclass(cls.__name__, cls.__bases__, orig_vars)
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return wrapper
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import time
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from secop.errors import ProgrammingError
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from secop.datatypes import EnumType
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from secop.params import Parameter
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EVENT_ONLY_ON_CHANGED_VALUES = True
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# warning: MAGIC!
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class ModuleMeta(type):
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"""Metaclass
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joining the class's properties, parameters and commands dicts with
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those of base classes.
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also creates getters/setter for parameter access
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and wraps read_*/write_* methods
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(so the dispatcher will get notfied of changed values)
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"""
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def __new__(mcs, name, bases, attrs):
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newtype = type.__new__(mcs, name, bases, attrs)
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if '__constructed__' in attrs:
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return newtype
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# merge properties, Parameter and commands from all sub-classes
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for entry in ['properties', 'parameters', 'commands']:
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newentry = {}
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for base in reversed(bases):
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if hasattr(base, entry):
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newentry.update(getattr(base, entry))
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newentry.update(attrs.get(entry, {}))
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setattr(newtype, entry, newentry)
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# apply Overrides from all sub-classes
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newparams = getattr(newtype, 'parameters')
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for base in reversed(bases):
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overrides = getattr(base, 'overrides', {})
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for n, o in overrides.items():
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newparams[n] = o.apply(newparams[n].copy())
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for n, o in attrs.get('overrides', {}).items():
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newparams[n] = o.apply(newparams[n].copy())
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# Correct naming of EnumTypes
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for k, v in newparams.items():
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if isinstance(v.datatype, EnumType) and not v.datatype._enum.name:
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v.datatype._enum.name = k
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# check validity of Parameter entries
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for pname, pobj in newtype.parameters.items():
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# XXX: allow dicts for overriding certain aspects only.
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if not isinstance(pobj, Parameter):
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raise ProgrammingError('%r: Parameters entry %r should be a '
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'Parameter object!' % (name, pname))
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# XXX: create getters for the units of params ??
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# wrap of reading/writing funcs
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rfunc = attrs.get('read_' + pname, None)
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for base in bases:
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if rfunc is not None:
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break
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rfunc = getattr(base, 'read_' + pname, None)
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def wrapped_rfunc(self, maxage=0, pname=pname, rfunc=rfunc):
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if rfunc:
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self.log.debug("rfunc(%s): call %r" % (pname, rfunc))
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value = rfunc(self, maxage)
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else:
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# return cached value
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self.log.debug("rfunc(%s): return cached value" % pname)
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value = self.parameters[pname].value
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setattr(self, pname, value) # important! trigger the setter
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return value
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if rfunc:
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wrapped_rfunc.__doc__ = rfunc.__doc__
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if getattr(rfunc, '__wrapped__', False) is False:
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setattr(newtype, 'read_' + pname, wrapped_rfunc)
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wrapped_rfunc.__wrapped__ = True
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if not pobj.readonly:
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wfunc = attrs.get('write_' + pname, None)
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for base in bases:
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if wfunc is not None:
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break
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wfunc = getattr(base, 'write_' + pname, None)
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def wrapped_wfunc(self, value, pname=pname, wfunc=wfunc):
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self.log.debug("wfunc(%s): set %r" % (pname, value))
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pobj = self.parameters[pname]
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value = pobj.datatype.validate(value)
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if wfunc:
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self.log.debug('calling %r(%r)' % (wfunc, value))
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value = wfunc(self, value) or value
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# XXX: use setattr or direct manipulation
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# of self.parameters[pname]?
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setattr(self, pname, value)
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return value
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if wfunc:
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wrapped_wfunc.__doc__ = wfunc.__doc__
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if getattr(wfunc, '__wrapped__', False) is False:
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setattr(newtype, 'write_' + pname, wrapped_wfunc)
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wrapped_wfunc.__wrapped__ = True
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def getter(self, pname=pname):
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return self.parameters[pname].value
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def setter(self, value, pname=pname):
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pobj = self.parameters[pname]
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value = pobj.datatype.validate(value)
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pobj.timestamp = time.time()
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if (not EVENT_ONLY_ON_CHANGED_VALUES) or (value != pobj.value):
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pobj.value = value
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# also send notification
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if self.parameters[pname].export:
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self.log.debug('%s is now %r' % (pname, value))
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self.DISPATCHER.announce_update(self, pname, pobj)
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setattr(newtype, pname, property(getter, setter))
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# also collect/update information about Command's
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setattr(newtype, 'commands', getattr(newtype, 'commands', {}))
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for attrname in attrs:
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if attrname.startswith('do_'):
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if attrname[3:] not in newtype.commands:
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raise ProgrammingError('%r: command %r has to be specified '
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'explicitly!' % (name, attrname[3:]))
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attrs['__constructed__'] = True
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return newtype
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