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lib64
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python2.7
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gobject
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propertyhelper.py
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# -*- Mode: Python; py-indent-offset: 4 -*- # pygobject - Python bindings for the GObject library # Copyright (C) 2007 Johan Dahlin # # gobject/propertyhelper.py: GObject property wrapper/helper # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library 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 # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 # USA import sys import gobject._gobject _gobject = sys.modules['gobject._gobject'] from gobject.constants import \ TYPE_NONE, TYPE_INTERFACE, TYPE_CHAR, TYPE_UCHAR, \ TYPE_BOOLEAN, TYPE_INT, TYPE_UINT, TYPE_LONG, \ TYPE_ULONG, TYPE_INT64, TYPE_UINT64, TYPE_ENUM, \ TYPE_FLAGS, TYPE_FLOAT, TYPE_DOUBLE, TYPE_STRING, \ TYPE_POINTER, TYPE_BOXED, TYPE_PARAM, TYPE_OBJECT, \ TYPE_PYOBJECT from gobject.constants import \ G_MINFLOAT, G_MAXFLOAT, G_MINDOUBLE, G_MAXDOUBLE, \ G_MININT, G_MAXINT, G_MAXUINT, G_MINLONG, G_MAXLONG, \ G_MAXULONG if sys.version_info >= (3, 0): _basestring = str _long = int else: _basestring = basestring _long = long class property(object): """ Creates a new property which in conjunction with GObject subclass will create a property proxy: >>> class MyObject(gobject.GObject): >>> ... prop = gobject.property(type=str) >>> obj = MyObject() >>> obj.prop = 'value' >>> obj.prop 'value' The API is similar to the builtin property: class AnotherObject(gobject.GObject): @gobject.property def prop(self): return ... Which will create a read-only property called prop. """ class __metaclass__(type): def __repr__(self): return "<class 'gobject.property'>" def __init__(self, getter=None, setter=None, type=None, default=None, nick='', blurb='', flags=_gobject.PARAM_READWRITE, minimum=None, maximum=None): """ @param getter: getter to get the value of the property @type getter: callable @param setter: setter to set the value of the property @type setter: callable @param type: type of property @type type: type @param default: default value @param nick: short description @type bick: string @param blurb: long description @type blurb: string @param flags: parameter flags, one of: - gobject.PARAM_READABLE - gobject.PARAM_READWRITE - gobject.PARAM_WRITABLE - gobject.PARAM_CONSTRUCT - gobject.PARAM_CONSTRUCT_ONLY - gobject.PARAM_LAX_VALIDATION @keyword minimum: minimum allowed value (int, float, long only) @keyword maximum: maximum allowed value (int, float, long only) """ if getter and not setter: setter = self._readonly_setter elif setter and not getter: getter = self._writeonly_getter elif not setter and not getter: getter = self._default_getter setter = self._default_setter self.getter = getter self.setter = setter if type is None: type = object self.type = self._type_from_python(type) self.default = self._get_default(default) self._check_default() if not isinstance(nick, _basestring): raise TypeError("nick must be a string") self.nick = nick if not isinstance(blurb, _basestring): raise TypeError("blurb must be a string") self.blurb = blurb if flags < 0 or flags > 32: raise TypeError("invalid flag value: %r" % (flags,)) self.flags = flags if minimum is not None: if minimum < self._get_minimum(): raise TypeError( "Minimum for type %s cannot be lower than %d" % ( self.type, self._get_minimum())) else: minimum = self._get_minimum() self.minimum = minimum if maximum is not None: if maximum > self._get_maximum(): raise TypeError( "Maximum for type %s cannot be higher than %d" % ( self.type, self._get_maximum())) else: maximum = self._get_maximum() self.maximum = maximum self.name = None self._exc = None def __repr__(self): return '<gobject property %s (%s)>' % ( self.name or '(uninitialized)', _gobject.type_name(self.type)) def __get__(self, instance, klass): if instance is None: return self self._exc = None value = instance.get_property(self.name) if self._exc: exc = self._exc self._exc = None raise exc return value def __set__(self, instance, value): if instance is None: raise TypeError self._exc = None instance.set_property(self.name, value) if self._exc: exc = self._exc self._exc = None raise exc def _type_from_python(self, type_): if type_ == _long: return TYPE_LONG elif type_ == int: return TYPE_INT elif type_ == bool: return TYPE_BOOLEAN elif type_ == float: return TYPE_DOUBLE elif type_ == str: return TYPE_STRING elif type_ == object: return TYPE_PYOBJECT elif isinstance(type_, type) and issubclass(type_, _gobject.GObject): return type_.__gtype__ elif type_ in [TYPE_NONE, TYPE_INTERFACE, TYPE_CHAR, TYPE_UCHAR, TYPE_INT, TYPE_UINT, TYPE_BOOLEAN, TYPE_LONG, TYPE_ULONG, TYPE_INT64, TYPE_UINT64, TYPE_ENUM, TYPE_FLAGS, TYPE_FLOAT, TYPE_DOUBLE, TYPE_POINTER, TYPE_BOXED, TYPE_PARAM, TYPE_OBJECT, TYPE_STRING, TYPE_PYOBJECT]: return type_ else: raise TypeError("Unsupported type: %r" % (type_,)) def _get_default(self, default): ptype = self.type if default is not None: return default if ptype in [TYPE_INT, TYPE_UINT, TYPE_LONG, TYPE_ULONG, TYPE_INT64, TYPE_UINT64]: return 0 elif ptype == TYPE_STRING: return '' elif ptype == TYPE_FLOAT or ptype == TYPE_DOUBLE: return 0.0 else: return None def _check_default(self): ptype = self.type default = self.default if (ptype == TYPE_BOOLEAN and (default not in (True, False))): raise TypeError( "default must be True or False, not %r" % (default,)) elif ptype == TYPE_PYOBJECT: if default is not None: raise TypeError("object types does not have default values") def _get_minimum(self): ptype = self.type if ptype in [TYPE_UINT, TYPE_ULONG, TYPE_UINT64]: return 0 # Remember that G_MINFLOAT and G_MINDOUBLE are something different. elif ptype == TYPE_FLOAT: return -G_MAXFLOAT elif ptype == TYPE_DOUBLE: return -G_MAXDOUBLE elif ptype == TYPE_INT: return G_MININT elif ptype == TYPE_LONG: return G_MINLONG elif ptype == TYPE_INT64: return -2 ** 62 - 1 return None def _get_maximum(self): ptype = self.type if ptype == TYPE_UINT: return G_MAXUINT elif ptype == TYPE_ULONG: return G_MAXULONG elif ptype == TYPE_INT64: return 2 ** 62 - 1 elif ptype == TYPE_UINT64: return 2 ** 63 - 1 elif ptype == TYPE_FLOAT: return G_MAXFLOAT elif ptype == TYPE_DOUBLE: return G_MAXDOUBLE elif ptype == TYPE_INT: return G_MAXINT elif ptype == TYPE_LONG: return G_MAXLONG return None # # Getter and Setter # def _default_setter(self, instance, value): setattr(instance, '_property_helper_'+self.name, value) def _default_getter(self, instance): return getattr(instance, '_property_helper_'+self.name, self.default) def _readonly_setter(self, instance, value): self._exc = TypeError("%s property of %s is read-only" % ( self.name, type(instance).__name__)) def _writeonly_getter(self, instance): self._exc = TypeError("%s property of %s is write-only" % ( self.name, type(instance).__name__)) # # Public API # def get_pspec_args(self): ptype = self.type if ptype in [TYPE_INT, TYPE_UINT, TYPE_LONG, TYPE_ULONG, TYPE_INT64, TYPE_UINT64, TYPE_FLOAT, TYPE_DOUBLE]: args = self._get_minimum(), self._get_maximum(), self.default elif ptype == TYPE_STRING or ptype == TYPE_BOOLEAN: args = (self.default,) elif ptype == TYPE_PYOBJECT: args = () elif ptype.is_a(TYPE_OBJECT): args = () else: raise NotImplementedError(ptype) return (self.type, self.nick, self.blurb) + args + (self.flags,)