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python/src/extension_class.cpp
Dave Abrahams 2e5d8dbff7 This commit was generated by cvs2svn to compensate for changes in r711,
which included commits to RCS files with non-trunk default branches.


[SVN r8328]
2000-11-26 15:49:26 +00:00

684 lines
22 KiB
C++

// (C) Copyright David Abrahams 2000. Permission to copy, use, modify, sell and
// distribute this software is granted provided this copyright notice appears
// in all copies. This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
// The author gratefully acknowleges the support of Dragon Systems, Inc., in
// producing this work.
#include <boost/python/detail/extension_class.hpp>
#include <cstring>
#include <boost/utility.hpp>
namespace boost { namespace python {
namespace detail {
struct operator_dispatcher
: public PyObject
{
static PyTypeObject type_obj;
static PyNumberMethods number_methods;
static operator_dispatcher* create(const ref& o, const ref& s);
ref m_object;
ref m_self;
// data members for allocation/deallocation optimization
operator_dispatcher* m_free_list_link;
static operator_dispatcher* free_list;
private:
// only accessible through create()
operator_dispatcher(const ref& o, const ref& s);
};
operator_dispatcher* operator_dispatcher::free_list = 0;
}}} // namespace boost::python::detail
BOOST_PYTHON_BEGIN_CONVERSION_NAMESPACE
inline PyObject* to_python(boost::python::detail::operator_dispatcher* n) { return n; }
BOOST_PYTHON_END_CONVERSION_NAMESPACE
namespace boost { namespace python {
namespace detail {
tuple extension_class_coerce(ref l, ref r)
{
// Introduced sequence points for exception-safety.
ref first(operator_dispatcher::create(l, l));
ref second;
if(r->ob_type == &operator_dispatcher::type_obj)
{
second = r;
}
else
{
second = ref(operator_dispatcher::create(r, ref()));
}
return boost::python::tuple(first, second);
}
enum { unwrap_exception_code = -1000 };
int unwrap_args(PyObject* left, PyObject* right, PyObject*& self, PyObject*& other)
{
if (left->ob_type != &operator_dispatcher::type_obj ||
right->ob_type != &operator_dispatcher::type_obj)
{
PyErr_SetString(PyExc_RuntimeError, "operator_dispatcher::unwrap_args(): expecting operator_dispatcher arguments only!");
return unwrap_exception_code;
}
typedef reference<operator_dispatcher> DPtr;
DPtr lwrapper(static_cast<operator_dispatcher*>(left), DPtr::increment_count);
DPtr rwrapper(static_cast<operator_dispatcher*>(right), DPtr::increment_count);
if (lwrapper->m_self.get() != 0)
{
self = lwrapper->m_self.get();
other = rwrapper->m_object.get();
return 0;
}
else
{
self = rwrapper->m_self.get();
other = lwrapper->m_object.get();
return 1;
}
}
int unwrap_pow_args(PyObject* left, PyObject* right, PyObject* m,
PyObject*& self, PyObject*& first, PyObject*& second)
{
if (left->ob_type != &operator_dispatcher::type_obj ||
right->ob_type != &operator_dispatcher::type_obj ||
m->ob_type != &operator_dispatcher::type_obj)
{
PyErr_SetString(PyExc_RuntimeError, "operator_dispatcher::unwrap_pow_args(): expecting operator_dispatcher arguments only!");
return unwrap_exception_code;
}
typedef reference<operator_dispatcher> DPtr;
DPtr lwrapper(static_cast<operator_dispatcher*>(left), DPtr::increment_count);
DPtr rwrapper(static_cast<operator_dispatcher*>(right), DPtr::increment_count);
DPtr mwrapper(static_cast<operator_dispatcher*>(m), DPtr::increment_count);
if (lwrapper->m_self.get() != 0)
{
self = lwrapper->m_self.get();
first = rwrapper->m_object.get();
second = mwrapper->m_object.get();
return 0;
}
else if (rwrapper->m_self.get() != 0)
{
self = rwrapper->m_self.get();
first = lwrapper->m_object.get();
second = mwrapper->m_object.get();
return 1;
}
else
{
self = mwrapper->m_self.get();
first = lwrapper->m_object.get();
second = rwrapper->m_object.get();
return 2;
}
}
extension_instance* get_extension_instance(PyObject* p)
{
// The object's type will just be some class_t<extension_instance> object,
// but if its meta-type is right, then it is an extension_instance.
if (p->ob_type->ob_type != extension_meta_class())
{
PyErr_SetString(PyExc_TypeError, p->ob_type->tp_name);
throw boost::python::argument_error();
}
return static_cast<extension_instance*>(p);
}
void
extension_instance::add_implementation(std::auto_ptr<instance_holder_base> holder)
{
for (held_objects::const_iterator p = m_wrapped_objects.begin();
p != m_wrapped_objects.end(); ++p)
{
if (typeid(*holder) == typeid(**p))
{
PyErr_SetString(PyExc_RuntimeError, "Base class already initialized");
throw error_already_set();
}
}
m_wrapped_objects.push_back(holder.release());
}
extension_instance::extension_instance(PyTypeObject* class_)
: instance(class_)
{
}
extension_instance::~extension_instance()
{
for (held_objects::const_iterator p = m_wrapped_objects.begin(),
finish = m_wrapped_objects.end();
p != finish; ++p)
{
delete *p;
}
}
meta_class<extension_instance>* extension_meta_class()
{
static meta_class<extension_instance> result;
return &result;
}
typedef class_t<extension_instance> extension_class_t;
bool is_subclass(const extension_class_t* derived,
const PyObject* possible_base)
{
tuple bases = derived->bases();
for (std::size_t i = 0, size = bases.size(); i < size; ++i)
{
const PyObject* base = bases[i].get();
if (base == possible_base)
return true;
if (base->ob_type == extension_meta_class())
{
const extension_class_t* base_class = downcast<const extension_class_t>(base);
if (is_subclass(base_class, possible_base))
return true;
}
}
return false;
}
// Return true iff obj is an obj of target_class
bool is_instance(extension_instance* obj,
class_t<extension_instance>* target_class)
{
if (obj->ob_type == target_class)
return true;
else
{
return is_subclass(
downcast<class_t<extension_instance> >(obj->ob_type).get(),
as_object(target_class));
}
}
void two_string_error(PyObject* exception_object, const char* format, const char* s1, const char* s2)
{
char buffer[256];
std::size_t format_length = BOOST_CSTD_::strlen(format);
std::size_t length1 = BOOST_CSTD_::strlen(s1);
std::size_t length2 = BOOST_CSTD_::strlen(s2);
std::size_t additional_length = length1 + length2;
if (additional_length + format_length > format_length - 1)
{
std::size_t difference = sizeof(buffer) - 1 - additional_length;
length1 -= difference / 2;
additional_length -= difference / 2;
}
sprintf(buffer, format, length1, s1, length2, s2);
PyErr_SetString(exception_object, buffer);
if (exception_object == PyExc_TypeError)
throw argument_error();
else
throw error_already_set();
}
// This is called when an attempt has been made to convert the given obj to
// a C++ type for which it doesn't have any obj data. In that case, either
// the obj was not derived from the target_class, or the appropriate
// __init__ function wasn't called to initialize the obj data of the target class.
void report_missing_instance_data(
extension_instance* obj, // The object being converted
class_t<extension_instance>* target_class, // the extension class of the C++ type
const std::type_info& target_typeid, // The typeid of the C++ type
bool target_is_ptr)
{
char buffer[256];
if (is_instance(obj, target_class))
{
if (target_is_ptr)
{
two_string_error(PyExc_RuntimeError,
"Object of extension class '%.*s' does not wrap <%.*s>.",
obj->ob_type->tp_name, target_typeid.name());
}
else
{
const char message[] = "__init__ function for extension class '%.*s' was never called.";
sprintf(buffer, message, sizeof(buffer) - sizeof(message) - 1,
target_class->tp_name);
}
PyErr_SetString(PyExc_RuntimeError, buffer);
}
else if (target_class == 0)
{
const char message[] = "Cannot convert to <%.*s>; its Python class was never created or has been deleted.";
sprintf(buffer, message, sizeof(buffer) - sizeof(message) - 1, target_typeid.name());
PyErr_SetString(PyExc_RuntimeError, buffer);
}
else
{
two_string_error(PyExc_TypeError, "extension class '%.*s' is not convertible into '%.*s'.",
obj->ob_type->tp_name, target_class->tp_name);
}
}
void report_missing_instance_data(
extension_instance* obj, // The object being converted
class_t<extension_instance>* target_class, // the extension class of the C++ type
const std::type_info& target_typeid) // The typeid of the C++ type
{
report_missing_instance_data(obj, target_class, target_typeid, false);
}
void report_missing_ptr_data(
extension_instance* obj, // The object being converted
class_t<extension_instance>* target_class, // the extension class of the C++ type
const std::type_info& target_typeid) // The typeid of the C++ type
{
report_missing_instance_data(obj, target_class, target_typeid, true);
}
void report_missing_class_object(const std::type_info& info)
{
char buffer[256];
const char message[] = "Cannot convert <%.*s> to python; its Python class was never created or has been deleted.";
sprintf(buffer, message, sizeof(buffer) - sizeof(message) - 1, info.name());
PyErr_SetString(PyExc_RuntimeError, buffer);
throw error_already_set();
}
void report_released_smart_pointer(const std::type_info& info)
{
char buffer[256];
const char message[] = "Converting from python, pointer or smart pointer to <%.*s> is NULL.";
sprintf(buffer, message, sizeof(buffer) - sizeof(message) - 1, info.name());
PyErr_SetString(PyExc_RuntimeError, buffer);
throw argument_error();
}
read_only_setattr_function::read_only_setattr_function(const char* name)
: m_name(name)
{
}
PyObject* read_only_setattr_function::do_call(PyObject* /*args*/, PyObject* /*keywords*/) const
{
PyErr_SetObject(PyExc_AttributeError, ("'" + m_name + "' attribute is read-only").get());
return 0;
}
const char* read_only_setattr_function::description() const
{
return "uncallable";
}
extension_class_base::extension_class_base(const char* name)
: class_t<extension_instance>(
extension_meta_class(), string(name), tuple(), dictionary())
{
}
// This function is used in from_python() to convert wrapped classes that are
// related by inheritance. The problem is this: although C++ provides all necessary
// conversion operators, source and target of a conversion must be known at compile
// time. However, in Python we want to convert classes at runtime. The solution is to
// generate conversion functions at compile time, register them within the appropriate
// class objects and call them when a particular runtime conversion is required.
// If functions for any possible conversion have to be stored, their number will grow
// qudratically. To reduce this number, we actually store only conversion functions
// between adjacent levels in the inheritance tree. By traversing the tree recursively,
// we can build any allowed conversion as a concatenation of simple conversions. This
// traversal is done in the functions try_base_class_conversions() and
// try_derived_class_conversions(). If a particular conversion is impossible, all
// conversion functions will return a NULL pointer.
// The function extract_object_from_holder() attempts to actually extract the pointer
// to the contained object from an instance_holder_base (a wrapper class). A conversion
// of the held object to 'T *' is allowed when the conversion
// 'dynamic_cast<instance_holder<T> *>(an_instance_holder_base)' succeeds.
void* extension_class_base::try_class_conversions(instance_holder_base* object) const
{
void* result = try_derived_class_conversions(object);
if (result)
return result;
if (!object->held_by_value())
return try_base_class_conversions(object);
else
return 0;
}
void* extension_class_base::try_base_class_conversions(instance_holder_base* object) const
{
for (std::size_t i = 0; i < base_classes().size(); ++i)
{
if (base_classes()[i].convert == 0)
continue;
void* result1 = base_classes()[i].class_object->extract_object_from_holder(object);
if (result1)
return (*base_classes()[i].convert)(result1);
void* result2 = base_classes()[i].class_object->try_base_class_conversions(object);
if (result2)
return (*base_classes()[i].convert)(result2);
}
return 0;
}
void* extension_class_base::try_derived_class_conversions(instance_holder_base* object) const
{
for (std::size_t i = 0; i < derived_classes().size(); ++i)
{
void* result1 = derived_classes()[i].class_object->extract_object_from_holder(object);
if (result1)
return (*derived_classes()[i].convert)(result1);
void* result2 = derived_classes()[i].class_object->try_derived_class_conversions(object);
if (result2)
return (*derived_classes()[i].convert)(result2);
}
return 0;
}
void extension_class_base::add_method(function* method, const char* name)
{
add_method(reference<function>(method), name);
}
void extension_class_base::add_method(reference<function> method, const char* name)
{
// Add the attribute to the computed target
function::add_to_namespace(method, name, this->dict().get());
// If it is a special member function it should be enabled both here and there.
detail::enable_named_method(this, name);
}
void extension_class_base::add_constructor_object(function* init_fn)
{
add_method(init_fn, "__init__");
}
void extension_class_base::add_setter_method(function* setter_, const char* name)
{
reference<function> setter(setter_);
add_method(setter, (detail::setattr_string() + name + "__").c_str());
}
void extension_class_base::add_getter_method(function* getter_, const char* name)
{
reference<function> getter(getter_);
add_method(getter, (detail::getattr_string() + name + "__").c_str());
}
void extension_class_base::set_attribute(const char* name, PyObject* x_)
{
ref x(x_);
set_attribute(name, x);
}
void extension_class_base::set_attribute(const char* name, ref x)
{
dict().set_item(string(name), x);
if (PyCallable_Check(x.get()))
detail::enable_named_method(this, name);
}
operator_dispatcher::operator_dispatcher(const ref& o, const ref& s)
: m_object(o), m_self(s), m_free_list_link(0)
{
ob_refcnt = 1;
ob_type = &type_obj;
}
operator_dispatcher*
operator_dispatcher::create(const ref& object, const ref& self)
{
operator_dispatcher* const result = free_list;
if (result == 0)
return new operator_dispatcher(object, self);
free_list = result->m_free_list_link;
result->m_object = object;
result->m_self = self;
Py_INCREF(result);
return result;
}
extern "C"
{
void operator_dispatcher_dealloc(PyObject* self)
{
operator_dispatcher* obj = static_cast<operator_dispatcher*>(self);
obj->m_free_list_link = operator_dispatcher::free_list;
operator_dispatcher::free_list = obj;
obj->m_object.reset();
obj->m_self.reset();
}
int operator_dispatcher_coerce(PyObject** l, PyObject** r)
{
Py_INCREF(*l);
try
{
*r = operator_dispatcher::create(ref(*r, ref::increment_count), ref());
}
catch(...)
{
handle_exception();
return -1;
}
return 0;
}
#define PY_DEFINE_OPERATOR(id, symbol) \
PyObject* operator_dispatcher_call_##id(PyObject* left, PyObject* right) \
{ \
/* unwrap the arguments from their OperatorDispatcher */ \
PyObject* self; \
PyObject* other; \
int reverse = unwrap_args(left, right, self, other); \
if (reverse == unwrap_exception_code) \
return 0; \
\
/* call the function */ \
PyObject* result = \
PyEval_CallMethod(self, \
const_cast<char*>(reverse ? "__r" #id "__" : "__" #id "__"), \
const_cast<char*>("(O)"), \
other); \
if (result == 0 && PyErr_GivenExceptionMatches(PyErr_Occurred(), PyExc_AttributeError)) \
{ \
PyErr_Clear(); \
PyErr_SetString(PyExc_TypeError, "bad operand type(s) for " #symbol); \
} \
return result; \
}
PY_DEFINE_OPERATOR(add, +)
PY_DEFINE_OPERATOR(sub, -)
PY_DEFINE_OPERATOR(mul, *)
PY_DEFINE_OPERATOR(div, /)
PY_DEFINE_OPERATOR(mod, %)
PY_DEFINE_OPERATOR(divmod, divmod)
PY_DEFINE_OPERATOR(lshift, <<)
PY_DEFINE_OPERATOR(rshift, >>)
PY_DEFINE_OPERATOR(and, &)
PY_DEFINE_OPERATOR(xor, ^)
PY_DEFINE_OPERATOR(or, |)
/* coercion rules for heterogeneous pow():
pow(Foo, int): left, right coerced; m: None => reverse = 0
pow(int, Foo): left, right coerced; m: None => reverse = 1
pow(Foo, int, int): left, right, m coerced => reverse = 0
pow(int, Foo, int): left, right, m coerced => reverse = 1
pow(int, int, Foo): left, right, m coerced => reverse = 2
pow(Foo, Foo, int): left, right coerced; m coerced twice => reverse = 0
pow(Foo, int, Foo): left, right, m coerced => reverse = 0
pow(int, Foo, Foo): left, right, m coerced => reverse = 1
*/
PyObject* operator_dispatcher_call_pow(PyObject* left, PyObject* right, PyObject* m)
{
int reverse;
PyObject* self;
PyObject* first;
PyObject* second;
if (m->ob_type == Py_None->ob_type)
{
reverse = unwrap_args(left, right, self, first);
second = m;
}
else
{
reverse = unwrap_pow_args(left, right, m, self, first, second);
}
if (reverse == unwrap_exception_code)
return 0;
// call the function
PyObject* result =
PyEval_CallMethod(self,
const_cast<char*>((reverse == 0)
? "__pow__"
: (reverse == 1)
? "__rpow__"
: "__rrpow__"),
const_cast<char*>("(OO)"),
first, second);
if (result == 0 &&
(PyErr_GivenExceptionMatches(PyErr_Occurred(), PyExc_TypeError) ||
PyErr_GivenExceptionMatches(PyErr_Occurred(), PyExc_AttributeError)))
{
PyErr_Clear();
PyErr_SetString(PyExc_TypeError, "bad operand type(s) for pow()");
}
return result;
}
int operator_dispatcher_call_cmp(PyObject* left, PyObject* right)
{
// unwrap the arguments from their OperatorDispatcher
PyObject* self;
PyObject* other;
int reverse = unwrap_args(left, right, self, other);
if (reverse == unwrap_exception_code)
return -1;
// call the function
PyObject* result =
PyEval_CallMethod(self,
const_cast<char*>(reverse ? "__rcmp__" : "__cmp__"),
const_cast<char*>("(O)"),
other);
if (result == 0)
{
PyErr_Clear();
PyErr_SetString(PyExc_TypeError, "bad operand type(s) for cmp() or <");
return -1;
}
else
{
try
{
return BOOST_PYTHON_CONVERSION::from_python(result, type<int>());
}
catch(...)
{
PyErr_Clear();
PyErr_SetString(PyExc_TypeError, "cmp() didn't return int");
return -1;
}
}
}
} // extern "C"
PyTypeObject operator_dispatcher::type_obj =
{
PyObject_HEAD_INIT(&PyType_Type)
0,
const_cast<char*>("operator_dispatcher"),
sizeof(operator_dispatcher),
0,
&operator_dispatcher_dealloc,
0,
0,
0,
&operator_dispatcher_call_cmp,
0,
&operator_dispatcher::number_methods,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0,
0
};
PyNumberMethods operator_dispatcher::number_methods =
{
&operator_dispatcher_call_add,
&operator_dispatcher_call_sub,
&operator_dispatcher_call_mul,
&operator_dispatcher_call_div,
&operator_dispatcher_call_mod,
&operator_dispatcher_call_divmod,
&operator_dispatcher_call_pow,
0,
0,
0,
0,
0,
&operator_dispatcher_call_lshift,
&operator_dispatcher_call_rshift,
&operator_dispatcher_call_and,
&operator_dispatcher_call_xor,
&operator_dispatcher_call_or,
&operator_dispatcher_coerce,
0,
0,
0,
0,
0
};
} // namespace detail
}} // namespace boost::python