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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 | # -*- Mode: Python; py-indent-offset: 4 -*- # pygobject - Python bindings for the GObject library # Copyright (C) 2007 Johan Dahlin # # gi/_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, see <http://www.gnu.org/licenses/>. import sys import traceback from . import _gi from ._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, TYPE_GTYPE, TYPE_STRV, TYPE_VARIANT G_MAXFLOAT = _gi.G_MAXFLOAT G_MAXDOUBLE = _gi.G_MAXDOUBLE G_MININT = _gi.G_MININT G_MAXINT = _gi.G_MAXINT G_MAXUINT = _gi.G_MAXUINT G_MINLONG = _gi.G_MINLONG G_MAXLONG = _gi.G_MAXLONG G_MAXULONG = _gi.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 when used in conjunction with GObject subclass will create a Python property accessor for the GObject ParamSpec. :param callable getter: getter to get the value of the property :param callable setter: setter to set the value of the property :param type type: type of property :param default: default value, must match the property type. :param str nick: short description :param str blurb: long description :param GObject.ParamFlags flags: parameter flags :keyword minimum: minimum allowed value (int, float, long only) :keyword maximum: maximum allowed value (int, float, long only) .. code-block:: python class MyObject(GObject.Object): prop = GObject.Property(type=str) obj = MyObject() obj.prop = 'value' obj.prop # now is 'value' The API is similar to the builtin :py:func:`property`: .. code-block:: python class AnotherObject(GObject.Object): value = 0 @GObject.Property def prop(self): 'Read only property.' return 1 @GObject.Property(type=int) def propInt(self): 'Read-write integer property.' return self.value @propInt.setter def propInt(self, value): self.value = value """ _type_from_pytype_lookup = { # Put long_ first in case long_ and int are the same so int clobbers long_ _long: TYPE_LONG, int: TYPE_INT, bool: TYPE_BOOLEAN, float: TYPE_DOUBLE, str: TYPE_STRING, object: TYPE_PYOBJECT, } _min_value_lookup = { TYPE_UINT: 0, TYPE_ULONG: 0, TYPE_UINT64: 0, # Remember that G_MINFLOAT and G_MINDOUBLE are something different. TYPE_FLOAT: -G_MAXFLOAT, TYPE_DOUBLE: -G_MAXDOUBLE, TYPE_INT: G_MININT, TYPE_LONG: G_MINLONG, TYPE_INT64: -2 ** 63, } _max_value_lookup = { TYPE_UINT: G_MAXUINT, TYPE_ULONG: G_MAXULONG, TYPE_INT64: 2 ** 63 - 1, TYPE_UINT64: 2 ** 64 - 1, TYPE_FLOAT: G_MAXFLOAT, TYPE_DOUBLE: G_MAXDOUBLE, TYPE_INT: G_MAXINT, TYPE_LONG: G_MAXLONG, } _default_lookup = { TYPE_INT: 0, TYPE_UINT: 0, TYPE_LONG: 0, TYPE_ULONG: 0, TYPE_INT64: 0, TYPE_UINT64: 0, TYPE_STRING: '', TYPE_FLOAT: 0.0, TYPE_DOUBLE: 0.0, } class __metaclass__(type): def __repr__(self): return "<class 'GObject.Property'>" def __init__(self, getter=None, setter=None, type=None, default=None, nick='', blurb='', flags=_gi.PARAM_READWRITE, minimum=None, maximum=None): self.name = None 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 # Always clobber __doc__ with blurb even if blurb is empty because # we don't want the lengthy Property class documentation showing up # on instances. self.__doc__ = blurb self.flags = flags # Call after setting blurb for potential __doc__ usage. 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) # do not call self.setter() here, as this defines the property name # already self.fset = setter 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._exc = None def __repr__(self): return '<GObject Property %s (%s)>' % ( self.name or '(uninitialized)', _gi.type_name(self.type)) def __get__(self, instance, klass): if instance is None: return self self._exc = None # Simply return the result of fget directly, no need to go through GObject. # See: https://bugzilla.gnome.org/show_bug.cgi?id=723872 # We catch and print any exception occurring within the fget for compatibility # prior to the fast path addition from bug 723872, this should eventually # be removed and exceptions raised directly to the caller as in: # https://bugzilla.gnome.org/show_bug.cgi?id=575652 try: value = self.fget(instance) except Exception: traceback.print_exc() value = None 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 __call__(self, fget): """Allows application of the getter along with init arguments.""" return self.getter(fget) def getter(self, fget): """Set the getter function to fget. For use as a decorator.""" if fget.__doc__: # Always clobber docstring and blurb with the getter docstring. self.blurb = fget.__doc__ self.__doc__ = fget.__doc__ self.fget = fget return self def setter(self, fset): """Set the setter function to fset. For use as a decorator.""" self.fset = fset # with a setter decorator, we must ignore the name of the method in # install_properties, as this does not need to be a valid property name # and does not define the property name. So set the name here. if not self.name: self.name = self.fget.__name__ return self def _type_from_python(self, type_): if type_ in self._type_from_pytype_lookup: return self._type_from_pytype_lookup[type_] elif (isinstance(type_, type) and issubclass(type_, (_gi.GObject, _gi.GEnum, _gi.GFlags, _gi.GBoxed, _gi.GInterface))): 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_FLOAT, TYPE_DOUBLE, TYPE_POINTER, TYPE_BOXED, TYPE_PARAM, TYPE_OBJECT, TYPE_STRING, TYPE_PYOBJECT, TYPE_GTYPE, TYPE_STRV, TYPE_VARIANT): return type_ else: raise TypeError("Unsupported type: %r" % (type_,)) def _get_default(self, default): if default is not None: return default return self._default_lookup.get(self.type, 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") elif ptype == TYPE_GTYPE: if default is not None: raise TypeError("GType types does not have default values") elif _gi.type_is_a(ptype, TYPE_ENUM): if default is None: raise TypeError("enum properties needs a default value") elif not _gi.type_is_a(default, ptype): raise TypeError("enum value %s must be an instance of %r" % (default, ptype)) elif _gi.type_is_a(ptype, TYPE_FLAGS): if not _gi.type_is_a(default, ptype): raise TypeError("flags value %s must be an instance of %r" % (default, ptype)) elif _gi.type_is_a(ptype, TYPE_STRV) and default is not None: if not isinstance(default, list): raise TypeError("Strv value %s must be a list" % repr(default)) for val in default: if type(val) not in (str, bytes): raise TypeError("Strv value %s must contain only strings" % str(default)) elif _gi.type_is_a(ptype, TYPE_VARIANT) and default is not None: if not hasattr(default, '__gtype__') or not _gi.type_is_a(default, TYPE_VARIANT): raise TypeError("variant value %s must be an instance of %r" % (default, ptype)) def _get_minimum(self): return self._min_value_lookup.get(self.type, None) def _get_maximum(self): return self._max_value_lookup.get(self.type, 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.minimum, self.maximum, self.default elif (ptype == TYPE_STRING or ptype == TYPE_BOOLEAN or ptype.is_a(TYPE_ENUM) or ptype.is_a(TYPE_FLAGS) or ptype.is_a(TYPE_VARIANT)): args = (self.default,) elif ptype in (TYPE_PYOBJECT, TYPE_GTYPE): args = () elif ptype.is_a(TYPE_OBJECT) or ptype.is_a(TYPE_BOXED): args = () else: raise NotImplementedError(ptype) return (self.type, self.nick, self.blurb) + args + (self.flags,) def install_properties(cls): """ Scans the given class for instances of Property and merges them into the classes __gproperties__ dict if it exists or adds it if not. """ gproperties = cls.__dict__.get('__gproperties__', {}) props = [] for name, prop in cls.__dict__.items(): if isinstance(prop, Property): # not same as the built-in # if a property was defined with a decorator, it may already have # a name; if it was defined with an assignment (prop = Property(...)) # we set the property's name to the member name if not prop.name: prop.name = name # we will encounter the same property multiple times in case of # custom setter methods if prop.name in gproperties: if gproperties[prop.name] == prop.get_pspec_args(): continue raise ValueError('Property %s was already found in __gproperties__' % prop.name) gproperties[prop.name] = prop.get_pspec_args() props.append(prop) if not props: return cls.__gproperties__ = gproperties if 'do_get_property' in cls.__dict__ or 'do_set_property' in cls.__dict__: for prop in props: if prop.fget != prop._default_getter or prop.fset != prop._default_setter: raise TypeError( "GObject subclass %r defines do_get/set_property" " and it also uses a property with a custom setter" " or getter. This is not allowed" % (cls.__name__,)) def obj_get_property(self, pspec): name = pspec.name.replace('-', '_') return getattr(self, name, None) cls.do_get_property = obj_get_property def obj_set_property(self, pspec, value): name = pspec.name.replace('-', '_') prop = getattr(cls, name, None) if prop: prop.fset(self, value) cls.do_set_property = obj_set_property