pybind11/include/pybind11/cast.h
2016-03-15 15:07:55 +01:00

657 lines
24 KiB
C++

/*
pybind11/cast.h: Partial template specializations to cast between
C++ and Python types
Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
All rights reserved. Use of this source code is governed by a
BSD-style license that can be found in the LICENSE file.
*/
#pragma once
#include "pytypes.h"
#include "typeid.h"
#include "descr.h"
#include <array>
#include <limits>
NAMESPACE_BEGIN(pybind11)
/// Thin wrapper type used to treat certain data types as opaque (e.g. STL vectors, etc.)
template <typename Type> class opaque {
public:
template <typename... Args> opaque(Args&&... args) : value(std::forward<Args>(args)...) { }
operator Type&() { return value; }
operator const Type&() const { return value; }
operator Type*() { return &value; }
operator const Type*() const { return &value; }
Type* operator->() { return &value; }
const Type* operator->() const { return &value; }
private:
Type value;
};
NAMESPACE_BEGIN(detail)
/// Additional type information which does not fit into the PyTypeObject
struct type_info {
PyTypeObject *type;
size_t type_size;
void (*init_holder)(PyObject *, const void *);
std::vector<PyObject *(*)(PyObject *, PyTypeObject *) > implicit_conversions;
buffer_info *(*get_buffer)(PyObject *, void *) = nullptr;
void *get_buffer_data = nullptr;
};
PYBIND11_NOINLINE inline internals &get_internals() {
static internals *internals_ptr = nullptr;
if (internals_ptr)
return *internals_ptr;
handle builtins(PyEval_GetBuiltins());
const char *id = PYBIND11_INTERNALS_ID;
capsule caps(builtins[id]);
if (caps.check()) {
internals_ptr = caps;
} else {
internals_ptr = new internals();
builtins[id] = capsule(internals_ptr);
}
return *internals_ptr;
}
PYBIND11_NOINLINE inline detail::type_info* get_type_info(PyTypeObject *type) {
auto const &type_dict = get_internals().registered_types_py;
do {
auto it = type_dict.find(type);
if (it != type_dict.end())
return (detail::type_info *) it->second;
type = type->tp_base;
if (!type)
pybind11_fail("pybind11::detail::get_type_info: unable to find type object!");
} while (true);
}
PYBIND11_NOINLINE inline detail::type_info *get_type_info(const std::type_info &tp) {
auto &types = get_internals().registered_types_cpp;
auto it = types.find(std::type_index(tp));
if (it != types.end())
return (detail::type_info *) it->second;
return nullptr;
}
PYBIND11_NOINLINE inline handle get_type_handle(const std::type_info &tp) {
detail::type_info *type_info = get_type_info(tp);
return handle(type_info ? ((PyObject *) type_info->type) : nullptr);
}
PYBIND11_NOINLINE inline std::string error_string() {
std::string errorString;
PyThreadState *tstate = PyThreadState_GET();
if (tstate == nullptr)
return "";
if (tstate->curexc_type) {
errorString += (std::string) handle(tstate->curexc_type).str();
errorString += ": ";
}
if (tstate->curexc_value)
errorString += (std::string) handle(tstate->curexc_value).str();
return errorString;
}
PYBIND11_NOINLINE inline handle get_object_handle(const void *ptr) {
auto instances = get_internals().registered_instances;
auto it = instances.find(ptr);
if (it == instances.end())
return handle();
return handle((PyObject *) it->second);
}
class type_caster_generic {
public:
PYBIND11_NOINLINE type_caster_generic(const std::type_info &type_info)
: typeinfo(get_type_info(type_info)) { }
PYBIND11_NOINLINE bool load(handle src, bool convert) {
if (!src || !typeinfo)
return false;
if (src.ptr() == Py_None) {
value = nullptr;
return true;
} else if (PyType_IsSubtype(Py_TYPE(src.ptr()), typeinfo->type)) {
value = ((instance<void> *) src.ptr())->value;
return true;
}
if (convert) {
for (auto &converter : typeinfo->implicit_conversions) {
temp = object(converter(src.ptr(), typeinfo->type), false);
if (load(temp, false))
return true;
}
}
return false;
}
PYBIND11_NOINLINE static handle cast(const void *_src, return_value_policy policy, handle parent,
const std::type_info *type_info,
void *(*copy_constructor)(const void *),
const void *existing_holder = nullptr) {
void *src = const_cast<void *>(_src);
if (src == nullptr)
return handle(Py_None).inc_ref();
// avoid an issue with internal references matching their parent's address
bool dont_cache = policy == return_value_policy::reference_internal &&
parent && ((instance<void> *) parent.ptr())->value == (void *) src;
auto& internals = get_internals();
auto it_instance = internals.registered_instances.find(src);
if (it_instance != internals.registered_instances.end() && !dont_cache)
return handle((PyObject *) it_instance->second).inc_ref();
auto it = internals.registered_types_cpp.find(std::type_index(*type_info));
if (it == internals.registered_types_cpp.end()) {
std::string tname = type_info->name();
detail::clean_type_id(tname);
std::string msg = "Unregistered type : " + tname;
PyErr_SetString(PyExc_TypeError, msg.c_str());
return handle();
}
auto tinfo = (const detail::type_info *) it->second;
object inst(PyType_GenericAlloc(tinfo->type, 0), false);
auto wrapper = (instance<void> *) inst.ptr();
wrapper->value = src;
wrapper->owned = true;
wrapper->parent = nullptr;
if (policy == return_value_policy::automatic)
policy = return_value_policy::take_ownership;
if (policy == return_value_policy::copy) {
wrapper->value = copy_constructor(wrapper->value);
if (wrapper->value == nullptr)
throw cast_error("return_value_policy = copy, but the object is non-copyable!");
} else if (policy == return_value_policy::reference) {
wrapper->owned = false;
} else if (policy == return_value_policy::reference_internal) {
wrapper->owned = false;
wrapper->parent = parent.inc_ref().ptr();
}
tinfo->init_holder(inst.ptr(), existing_holder);
if (!dont_cache)
internals.registered_instances[wrapper->value] = inst.ptr();
return inst.release();
}
protected:
const type_info *typeinfo = nullptr;
void *value = nullptr;
object temp;
};
/// Generic type caster for objects stored on the heap
template <typename type, typename Enable = void> class type_caster : public type_caster_generic {
public:
static PYBIND11_DESCR name() { return type_descr(_<type>()); }
type_caster() : type_caster_generic(typeid(type)) { }
static handle cast(const type &src, return_value_policy policy, handle parent) {
if (policy == return_value_policy::automatic)
policy = return_value_policy::copy;
return type_caster_generic::cast(&src, policy, parent, &typeid(type), &copy_constructor);
}
static handle cast(const type *src, return_value_policy policy, handle parent) {
return type_caster_generic::cast(src, policy, parent, &typeid(type), &copy_constructor);
}
operator type*() { return (type *) value; }
operator type&() { return *((type *) value); }
protected:
template <typename T = type, typename std::enable_if<detail::is_copy_constructible<T>::value, int>::type = 0>
static void *copy_constructor(const void *arg) {
return (void *) new type(*((const type *) arg));
}
template <typename T = type, typename std::enable_if<!detail::is_copy_constructible<T>::value, int>::type = 0>
static void *copy_constructor(const void *) { return nullptr; }
};
#define PYBIND11_TYPE_CASTER(type, py_name) \
protected: \
type value; \
public: \
static PYBIND11_DESCR name() { return type_descr(py_name); } \
static handle cast(const type *src, return_value_policy policy, handle parent) { \
return cast(*src, policy, parent); \
} \
operator type*() { return &value; } \
operator type&() { return value; }
#define PYBIND11_DECLARE_HOLDER_TYPE(type, holder_type) \
namespace pybind11 { namespace detail { \
template <typename type> class type_caster<holder_type> \
: public type_caster_holder<type, holder_type> { }; \
}}
template <typename T>
struct type_caster<
T, typename std::enable_if<std::is_integral<T>::value ||
std::is_floating_point<T>::value>::type> {
typedef typename std::conditional<sizeof(T) <= sizeof(long), long, long long>::type _py_type_0;
typedef typename std::conditional<std::is_signed<T>::value, _py_type_0, typename std::make_unsigned<_py_type_0>::type>::type _py_type_1;
typedef typename std::conditional<std::is_floating_point<T>::value, double, _py_type_1>::type py_type;
public:
bool load(handle src, bool) {
py_type py_value;
if (std::is_floating_point<T>::value) {
py_value = (py_type) PyFloat_AsDouble(src.ptr());
} else if (sizeof(T) <= sizeof(long)) {
if (std::is_signed<T>::value)
py_value = (py_type) PyLong_AsLong(src.ptr());
else
py_value = (py_type) PyLong_AsUnsignedLong(src.ptr());
} else {
if (std::is_signed<T>::value)
py_value = (py_type) PYBIND11_LONG_AS_LONGLONG(src.ptr());
else
py_value = (py_type) PYBIND11_LONG_AS_UNSIGNED_LONGLONG(src.ptr());
}
if ((py_value == (py_type) -1 && PyErr_Occurred()) ||
(std::is_integral<T>::value && sizeof(py_type) != sizeof(T) &&
(py_value < (py_type) std::numeric_limits<T>::min() ||
py_value > (py_type) std::numeric_limits<T>::max()))) {
PyErr_Clear();
return false;
}
value = (T) py_value;
return true;
}
static handle cast(T src, return_value_policy /* policy */, handle /* parent */) {
if (std::is_floating_point<T>::value) {
return PyFloat_FromDouble((double) src);
} else if (sizeof(T) <= sizeof(long)) {
if (std::is_signed<T>::value)
return PyLong_FromLong((long) src);
else
return PyLong_FromUnsignedLong((unsigned long) src);
} else {
if (std::is_signed<T>::value)
return PyLong_FromLongLong((long long) src);
else
return PyLong_FromUnsignedLongLong((unsigned long long) src);
}
}
static handle cast(const T *src, return_value_policy policy, handle parent) {
return cast(*src, policy, parent);
}
template <typename T2 = T, typename std::enable_if<std::is_integral<T2>::value, int>::type = 0>
static PYBIND11_DESCR name() { return type_descr(_("int")); }
template <typename T2 = T, typename std::enable_if<!std::is_integral<T2>::value, int>::type = 0>
static PYBIND11_DESCR name() { return type_descr(_("float")); }
operator T*() { return &value; }
operator T&() { return value; }
protected:
T value;
};
template <> class type_caster<void_type> {
public:
bool load(handle, bool) { return false; }
static handle cast(void_type, return_value_policy /* policy */, handle /* parent */) {
return handle(Py_None).inc_ref();
}
PYBIND11_TYPE_CASTER(void_type, _("NoneType"));
};
template <> class type_caster<void> : public type_caster<void_type> { };
template <> class type_caster<std::nullptr_t> : public type_caster<void_type> { };
template <> class type_caster<bool> {
public:
bool load(handle src, bool) {
if (src.ptr() == Py_True) { value = true; return true; }
else if (src.ptr() == Py_False) { value = false; return true; }
else return false;
}
static handle cast(bool src, return_value_policy /* policy */, handle /* parent */) {
return handle(src ? Py_True : Py_False).inc_ref();
}
PYBIND11_TYPE_CASTER(bool, _("bool"));
};
template <> class type_caster<std::string> {
public:
bool load(handle src, bool) {
object temp;
handle load_src = src;
if (PyUnicode_Check(load_src.ptr())) {
temp = object(PyUnicode_AsUTF8String(load_src.ptr()), false);
if (!temp) { PyErr_Clear(); return false; } // UnicodeEncodeError
load_src = temp;
}
char *buffer;
ssize_t length;
int err = PYBIND11_BYTES_AS_STRING_AND_SIZE(load_src.ptr(), &buffer, &length);
if (err == -1) { PyErr_Clear(); return false; } // TypeError
value = std::string(buffer, length);
return true;
}
static handle cast(const std::string &src, return_value_policy /* policy */, handle /* parent */) {
return PyUnicode_FromStringAndSize(src.c_str(), src.length());
}
PYBIND11_TYPE_CASTER(std::string, _(PYBIND11_STRING_NAME));
};
template <> class type_caster<std::wstring> {
public:
bool load(handle src, bool) {
object temp;
handle load_src = src;
if (!PyUnicode_Check(load_src.ptr())) {
temp = object(PyUnicode_FromObject(load_src.ptr()), false);
if (!temp) { PyErr_Clear(); return false; }
load_src = temp;
}
wchar_t *buffer = nullptr;
ssize_t length = -1;
#if PY_MAJOR_VERSION >= 3
buffer = PyUnicode_AsWideCharString(load_src.ptr(), &length);
#else
temp = object(
sizeof(wchar_t) == sizeof(short)
? PyUnicode_AsUTF16String(load_src.ptr())
: PyUnicode_AsUTF32String(load_src.ptr()), false);
if (temp) {
int err = PYBIND11_BYTES_AS_STRING_AND_SIZE(temp.ptr(), (char **) &buffer, &length);
if (err == -1) { buffer = nullptr; } // TypeError
length = length / sizeof(wchar_t) - 1; ++buffer; // Skip BOM
}
#endif
if (!buffer) { PyErr_Clear(); return false; }
value = std::wstring(buffer, length);
return true;
}
static handle cast(const std::wstring &src, return_value_policy /* policy */, handle /* parent */) {
return PyUnicode_FromWideChar(src.c_str(), src.length());
}
PYBIND11_TYPE_CASTER(std::wstring, _(PYBIND11_STRING_NAME));
};
template <> class type_caster<char> : public type_caster<std::string> {
public:
static handle cast(const char *src, return_value_policy /* policy */, handle /* parent */) {
return PyUnicode_FromString(src);
}
static handle cast(char src, return_value_policy /* policy */, handle /* parent */) {
char str[2] = { src, '\0' };
return PyUnicode_DecodeLatin1(str, 1, nullptr);
}
operator char*() { return (char *) value.c_str(); }
operator char() { if (value.length() > 0) return value[0]; else return '\0'; }
static PYBIND11_DESCR name() { return type_descr(_(PYBIND11_STRING_NAME)); }
};
template <> class type_caster<wchar_t> : public type_caster<std::wstring> {
public:
static handle cast(const wchar_t *src, return_value_policy /* policy */, handle /* parent */) {
return PyUnicode_FromWideChar(src, wcslen(src));
}
static handle cast(wchar_t src, return_value_policy /* policy */, handle /* parent */) {
wchar_t wstr[2] = { src, L'\0' };
return PyUnicode_FromWideChar(wstr, 1);
}
operator wchar_t*() { return (wchar_t *)value.c_str(); }
operator wchar_t() { if (value.length() > 0) return value[0]; else return L'\0'; }
static PYBIND11_DESCR name() { return type_descr(_(PYBIND11_STRING_NAME)); }
};
template <typename T1, typename T2> class type_caster<std::pair<T1, T2>> {
typedef std::pair<T1, T2> type;
public:
bool load(handle src, bool convert) {
if (!PyTuple_Check(src.ptr()) || PyTuple_Size(src.ptr()) != 2)
return false;
return first.load(PyTuple_GET_ITEM(src.ptr(), 0), convert) &&
second.load(PyTuple_GET_ITEM(src.ptr(), 1), convert);
}
static handle cast(const type &src, return_value_policy policy, handle parent) {
object o1 = object(type_caster<typename intrinsic_type<T1>::type>::cast(src.first, policy, parent), false);
object o2 = object(type_caster<typename intrinsic_type<T2>::type>::cast(src.second, policy, parent), false);
if (!o1 || !o2)
return handle();
tuple result(2);
PyTuple_SET_ITEM(result.ptr(), 0, o1.release().ptr());
PyTuple_SET_ITEM(result.ptr(), 1, o2.release().ptr());
return result.release();
}
static PYBIND11_DESCR name() {
return type_descr(
_("(") + type_caster<typename intrinsic_type<T1>::type>::name() +
_(", ") + type_caster<typename intrinsic_type<T2>::type>::name() + _(")"));
}
operator type() {
return type(first, second);
}
protected:
type_caster<typename intrinsic_type<T1>::type> first;
type_caster<typename intrinsic_type<T2>::type> second;
};
template <typename... Tuple> class type_caster<std::tuple<Tuple...>> {
typedef std::tuple<Tuple...> type;
public:
enum { size = sizeof...(Tuple) };
bool load(handle src, bool convert) {
return load(src, convert, typename make_index_sequence<sizeof...(Tuple)>::type());
}
static handle cast(const type &src, return_value_policy policy, handle parent) {
return cast(src, policy, parent, typename make_index_sequence<size>::type());
}
static PYBIND11_DESCR name() {
return type_descr(
_("(") +
detail::concat(type_caster<typename intrinsic_type<Tuple>::type>::name()...) +
_(")"));
}
template <typename ReturnValue, typename Func> typename std::enable_if<!std::is_void<ReturnValue>::value, ReturnValue>::type call(Func &&f) {
return call<ReturnValue>(std::forward<Func>(f), typename make_index_sequence<sizeof...(Tuple)>::type());
}
template <typename ReturnValue, typename Func> typename std::enable_if<std::is_void<ReturnValue>::value, void_type>::type call(Func &&f) {
call<ReturnValue>(std::forward<Func>(f), typename make_index_sequence<sizeof...(Tuple)>::type());
return void_type();
}
operator type() {
return cast(typename make_index_sequence<sizeof...(Tuple)>::type());
}
protected:
template <typename ReturnValue, typename Func, size_t ... Index> ReturnValue call(Func &&f, index_sequence<Index...>) {
return f((Tuple) std::get<Index>(value)...);
}
template <size_t ... Index> type cast(index_sequence<Index...>) {
return type((Tuple) std::get<Index>(value)...);
}
template <size_t ... Indices> bool load(handle src, bool convert, index_sequence<Indices...>) {
if (!PyTuple_Check(src.ptr()) || PyTuple_Size(src.ptr()) != size)
return false;
std::array<bool, size> success {{
(PyTuple_GET_ITEM(src.ptr(), Indices) != nullptr ? std::get<Indices>(value).load(PyTuple_GET_ITEM(src.ptr(), Indices), convert) : false)...
}};
(void) convert; /* avoid a warning when the tuple is empty */
for (bool r : success)
if (!r)
return false;
return true;
}
/* Implementation: Convert a C++ tuple into a Python tuple */
template <size_t ... Indices> static handle cast(const type &src, return_value_policy policy, handle parent, index_sequence<Indices...>) {
std::array<object, size> entries {{
object(type_caster<typename intrinsic_type<Tuple>::type>::cast(std::get<Indices>(src), policy, parent), false)...
}};
for (const auto &entry: entries)
if (!entry)
return handle();
tuple result(size);
int counter = 0;
for (auto & entry: entries)
PyTuple_SET_ITEM(result.ptr(), counter++, entry.release().ptr());
return result.release();
}
protected:
std::tuple<type_caster<typename intrinsic_type<Tuple>::type>...> value;
};
/// Type caster for holder types like std::shared_ptr, etc.
template <typename type, typename holder_type> class type_caster_holder : public type_caster<type> {
public:
using type_caster<type>::cast;
using type_caster<type>::typeinfo;
using type_caster<type>::value;
using type_caster<type>::temp;
using type_caster<type>::copy_constructor;
bool load(handle src, bool convert) {
if (!src || !typeinfo) {
return false;
} else if (src.ptr() == Py_None) {
value = nullptr;
return true;
} else if (PyType_IsSubtype(Py_TYPE(src.ptr()), typeinfo->type)) {
auto inst = (instance<type, holder_type> *) src.ptr();
value = (void *) inst->value;
holder = inst->holder;
return true;
}
if (convert) {
for (auto &converter : typeinfo->implicit_conversions) {
temp = object(converter(src.ptr(), typeinfo->type), false);
if (load(temp, false))
return true;
}
}
return false;
}
explicit operator type*() { return this->value; }
explicit operator type&() { return *(this->value); }
explicit operator holder_type*() { return &holder; }
// Workaround for Intel compiler bug
// see pybind11 issue 94
#if defined(__ICC) || defined(__INTEL_COMPILER)
operator holder_type&() { return holder; }
#else
explicit operator holder_type&() { return holder; }
#endif
static handle cast(const holder_type &src, return_value_policy policy, handle parent) {
return type_caster_generic::cast(
src.get(), policy, parent, &typeid(type), &copy_constructor, &src);
}
protected:
holder_type holder;
};
template <typename T> struct handle_type_name { static PYBIND11_DESCR name() { return _<T>(); } };
template <> struct handle_type_name<bytes> { static PYBIND11_DESCR name() { return _(PYBIND11_BYTES_NAME); } };
template <typename type>
struct type_caster<type, typename std::enable_if<std::is_base_of<handle, type>::value>::type> {
public:
template <typename T = type, typename std::enable_if<std::is_same<T, handle>::value, int>::type = 0>
bool load(handle src, bool /* convert */) { value = src; return value.check(); }
template <typename T = type, typename std::enable_if<!std::is_same<T, handle>::value, int>::type = 0>
bool load(handle src, bool /* convert */) { value = type(src, true); return value.check(); }
static handle cast(const handle &src, return_value_policy /* policy */, handle /* parent */) {
return src.inc_ref();
}
PYBIND11_TYPE_CASTER(type, handle_type_name<type>::name());
};
NAMESPACE_END(detail)
template <typename T> inline T cast(handle handle) {
detail::type_caster<typename detail::intrinsic_type<T>::type> conv;
if (!conv.load(handle, true))
throw cast_error("Unable to cast Python object to C++ type");
return (T) conv;
}
template <typename T> inline object cast(const T &value, return_value_policy policy = return_value_policy::automatic, handle parent = handle()) {
if (policy == return_value_policy::automatic)
policy = std::is_pointer<T>::value ? return_value_policy::take_ownership : return_value_policy::copy;
return object(detail::type_caster<typename detail::intrinsic_type<T>::type>::cast(value, policy, parent), false);
}
template <typename T> inline T handle::cast() const { return pybind11::cast<T>(*this); }
template <> inline void handle::cast() const { return; }
template <typename... Args> inline object handle::call(Args&&... args_) const {
const size_t size = sizeof...(Args);
std::array<object, size> args {
{ object(detail::type_caster<typename detail::intrinsic_type<Args>::type>::cast(
std::forward<Args>(args_), return_value_policy::reference, nullptr), false)... }
};
for (auto &arg_value : args)
if (!arg_value)
throw cast_error("handle::call(): unable to convert input "
"arguments to Python objects");
tuple args_tuple(size);
int counter = 0;
for (auto &arg_value : args)
PyTuple_SET_ITEM(args_tuple.ptr(), counter++, arg_value.release().ptr());
object result(PyObject_CallObject(m_ptr, args_tuple.ptr()), false);
if (!result)
throw error_already_set();
return result;
}
NAMESPACE_END(pybind11)