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/*########################################################################### # # Copyright (c) 2003 Zope Foundation and Contributors. # All Rights Reserved. # # This software is subject to the provisions of the Zope Public License, # Version 2.1 (ZPL). A copy of the ZPL should accompany this distribution. # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS # FOR A PARTICULAR PURPOSE. # ############################################################################*/ #include "Python.h" #include "structmember.h" #define TYPE(O) ((PyTypeObject*)(O)) #define OBJECT(O) ((PyObject*)(O)) #define CLASSIC(O) ((PyClassObject*)(O)) #ifndef PyVarObject_HEAD_INIT #define PyVarObject_HEAD_INIT(a, b) PyObject_HEAD_INIT(a) b, #endif #ifndef Py_TYPE #define Py_TYPE(o) ((o)->ob_type) #endif #if PY_MAJOR_VERSION >= 3 #define PY3K #endif static PyObject *str__dict__, *str__implemented__, *strextends; static PyObject *BuiltinImplementationSpecifications, *str__provides__; static PyObject *str__class__, *str__providedBy__; static PyObject *empty, *fallback, *str_implied, *str_cls, *str_implements; static PyObject *str__conform__, *str_call_conform, *adapter_hooks; static PyObject *str_uncached_lookup, *str_uncached_lookupAll; static PyObject *str_uncached_subscriptions; static PyObject *str_registry, *strro, *str_generation, *strchanged; static PyTypeObject *Implements; static int imported_declarations = 0; static int import_declarations(void) { PyObject *declarations, *i; declarations = PyImport_ImportModule("zope.interface.declarations"); if (declarations == NULL) return -1; BuiltinImplementationSpecifications = PyObject_GetAttrString( declarations, "BuiltinImplementationSpecifications"); if (BuiltinImplementationSpecifications == NULL) return -1; empty = PyObject_GetAttrString(declarations, "_empty"); if (empty == NULL) return -1; fallback = PyObject_GetAttrString(declarations, "implementedByFallback"); if (fallback == NULL) return -1; i = PyObject_GetAttrString(declarations, "Implements"); if (i == NULL) return -1; if (! PyType_Check(i)) { PyErr_SetString(PyExc_TypeError, "zope.interface.declarations.Implements is not a type"); return -1; } Implements = (PyTypeObject *)i; Py_DECREF(declarations); imported_declarations = 1; return 0; } static PyTypeObject SpecType; /* Forward */ static PyObject * implementedByFallback(PyObject *cls) { if (imported_declarations == 0 && import_declarations() < 0) return NULL; return PyObject_CallFunctionObjArgs(fallback, cls, NULL); } static PyObject * implementedBy(PyObject *ignored, PyObject *cls) { /* Fast retrieval of implements spec, if possible, to optimize common case. Use fallback code if we get stuck. */ PyObject *dict = NULL, *spec; if (PyType_Check(cls)) { dict = TYPE(cls)->tp_dict; Py_XINCREF(dict); } if (dict == NULL) dict = PyObject_GetAttr(cls, str__dict__); if (dict == NULL) { /* Probably a security proxied class, use more expensive fallback code */ PyErr_Clear(); return implementedByFallback(cls); } spec = PyObject_GetItem(dict, str__implemented__); Py_DECREF(dict); if (spec) { if (imported_declarations == 0 && import_declarations() < 0) return NULL; if (PyObject_TypeCheck(spec, Implements)) return spec; /* Old-style declaration, use more expensive fallback code */ Py_DECREF(spec); return implementedByFallback(cls); } PyErr_Clear(); /* Maybe we have a builtin */ if (imported_declarations == 0 && import_declarations() < 0) return NULL; spec = PyDict_GetItem(BuiltinImplementationSpecifications, cls); if (spec != NULL) { Py_INCREF(spec); return spec; } /* We're stuck, use fallback */ return implementedByFallback(cls); } static PyObject * getObjectSpecification(PyObject *ignored, PyObject *ob) { PyObject *cls, *result; result = PyObject_GetAttr(ob, str__provides__); if (result != NULL && PyObject_TypeCheck(result, &SpecType)) return result; PyErr_Clear(); /* We do a getattr here so as not to be defeated by proxies */ cls = PyObject_GetAttr(ob, str__class__); if (cls == NULL) { PyErr_Clear(); if (imported_declarations == 0 && import_declarations() < 0) return NULL; Py_INCREF(empty); return empty; } result = implementedBy(NULL, cls); Py_DECREF(cls); return result; } static PyObject * providedBy(PyObject *ignored, PyObject *ob) { PyObject *result, *cls, *cp; result = PyObject_GetAttr(ob, str__providedBy__); if (result == NULL) { PyErr_Clear(); return getObjectSpecification(NULL, ob); } /* We want to make sure we have a spec. We can't do a type check because we may have a proxy, so we'll just try to get the only attribute. */ if (PyObject_TypeCheck(result, &SpecType) || PyObject_HasAttr(result, strextends) ) return result; /* The object's class doesn't understand descriptors. Sigh. We need to get an object descriptor, but we have to be careful. We want to use the instance's __provides__,l if there is one, but only if it didn't come from the class. */ Py_DECREF(result); cls = PyObject_GetAttr(ob, str__class__); if (cls == NULL) return NULL; result = PyObject_GetAttr(ob, str__provides__); if (result == NULL) { /* No __provides__, so just fall back to implementedBy */ PyErr_Clear(); result = implementedBy(NULL, cls); Py_DECREF(cls); return result; } cp = PyObject_GetAttr(cls, str__provides__); if (cp == NULL) { /* The the class has no provides, assume we're done: */ PyErr_Clear(); Py_DECREF(cls); return result; } if (cp == result) { /* Oops, we got the provides from the class. This means the object doesn't have it's own. We should use implementedBy */ Py_DECREF(result); result = implementedBy(NULL, cls); } Py_DECREF(cls); Py_DECREF(cp); return result; } /* Get an attribute from an inst dict. Return a borrowed reference. This has a number of advantages: - It avoids layers of Python api - It doesn't waste time looking for descriptors - It fails wo raising an exception, although that shouldn't really matter. */ static PyObject * inst_attr(PyObject *self, PyObject *name) { PyObject **dictp, *v; dictp = _PyObject_GetDictPtr(self); if (dictp && *dictp && (v = PyDict_GetItem(*dictp, name))) return v; PyErr_SetObject(PyExc_AttributeError, name); return NULL; } static PyObject * Spec_extends(PyObject *self, PyObject *other) { PyObject *implied; implied = inst_attr(self, str_implied); if (implied == NULL) return NULL; #ifdef Py_True if (PyDict_GetItem(implied, other) != NULL) { Py_INCREF(Py_True); return Py_True; } Py_INCREF(Py_False); return Py_False; #else return PyInt_FromLong(PyDict_GetItem(implied, other) != NULL); #endif } static char Spec_extends__doc__[] = "Test whether a specification is or extends another" ; static char Spec_providedBy__doc__[] = "Test whether an interface is implemented by the specification" ; static PyObject * Spec_call(PyObject *self, PyObject *args, PyObject *kw) { PyObject *spec; if (! PyArg_ParseTuple(args, "O", &spec)) return NULL; return Spec_extends(self, spec); } static PyObject * Spec_providedBy(PyObject *self, PyObject *ob) { PyObject *decl, *item; decl = providedBy(NULL, ob); if (decl == NULL) return NULL; if (PyObject_TypeCheck(decl, &SpecType)) item = Spec_extends(decl, self); else /*