RYDE-WORK/pybind11
1
0
Fork 0
mirror of https://github.com/RYDE-WORK/pybind11.git synced 2026-01-22 23:15:36 +08:00
Code Issues Actions Packages Projects Releases Wiki Activity
pybind11/include/pybind11/cast.h
eirrgang 11c9f32c0f fix python version check (#705) 
Commit 11a337f1 added major and minor python version
checking to cast.h but does not use the macros defined
via the Python.h inclusion. This may be due to an
intention to use the variables defined by the cmake
module FindPythonInterpreter, but nothing in the
pybind11 repo does anything to convert the cmake
variables to preprocessor defines.
2017-03-01 10:53:38 +01:00

1585 lines
63 KiB
C++
Raw Blame History

/*
pybind11/cast.h: Partial template specializations to cast between
C++ and Python types
Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.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)
NAMESPACE_BEGIN(detail)
inline PyTypeObject *make_static_property_type();
inline PyTypeObject *make_default_metaclass();
/// 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 *);
void (*dealloc)(PyObject *);
std::vector<PyObject *(*)(PyObject *, PyTypeObject *)> implicit_conversions;
std::vector<std::pair<const std::type_info *, void *(*)(void *)>> implicit_casts;
std::vector<bool (*)(PyObject *, void *&)> *direct_conversions;
buffer_info *(*get_buffer)(PyObject *, void *) = nullptr;
void *get_buffer_data = nullptr;
/** A simple type never occurs as a (direct or indirect) parent
* of a class that makes use of multiple inheritance */
bool simple_type = true;
/* for base vs derived holder_type checks */
bool default_holder = true;
};
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;
if (builtins.contains(id) && isinstance<capsule>(builtins[id])) {
internals_ptr = capsule(builtins[id]);
} else {
internals_ptr = new internals();
#if defined(WITH_THREAD)
PyEval_InitThreads();
PyThreadState *tstate = PyThreadState_Get();
internals_ptr->tstate = PyThread_create_key();
PyThread_set_key_value(internals_ptr->tstate, tstate);
internals_ptr->istate = tstate->interp;
#endif
builtins[id] = capsule(internals_ptr);
internals_ptr->registered_exception_translators.push_front(
[](std::exception_ptr p) -> void {
try {
if (p) std::rethrow_exception(p);
} catch (error_already_set &e) { e.restore(); return;
} catch (const builtin_exception &e) { e.set_error(); return;
} catch (const std::bad_alloc &e) { PyErr_SetString(PyExc_MemoryError, e.what()); return;
} catch (const std::domain_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
} catch (const std::invalid_argument &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
} catch (const std::length_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
} catch (const std::out_of_range &e) { PyErr_SetString(PyExc_IndexError, e.what()); return;
} catch (const std::range_error &e) { PyErr_SetString(PyExc_ValueError, e.what()); return;
} catch (const std::exception &e) { PyErr_SetString(PyExc_RuntimeError, e.what()); return;
} catch (...) {
PyErr_SetString(PyExc_RuntimeError, "Caught an unknown exception!");
return;
}
}
);
internals_ptr->static_property_type = make_static_property_type();
internals_ptr->default_metaclass = make_default_metaclass();
}
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)
return nullptr;
} while (true);
}
PYBIND11_NOINLINE inline detail::type_info *get_type_info(const std::type_info &tp,
bool throw_if_missing = false) {
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;
if (throw_if_missing) {
std::string tname = tp.name();
detail::clean_type_id(tname);
pybind11_fail("pybind11::detail::get_type_info: unable to find type info for \"" + tname + "\"");
}
return nullptr;
}
PYBIND11_NOINLINE inline handle get_type_handle(const std::type_info &tp, bool throw_if_missing) {
detail::type_info *type_info = get_type_info(tp, throw_if_missing);
return handle(type_info ? ((PyObject *) type_info->type) : nullptr);
}
PYBIND11_NOINLINE inline bool isinstance_generic(handle obj, const std::type_info &tp) {
handle type = detail::get_type_handle(tp, false);
if (!type)
return false;
return isinstance(obj, type);
}
PYBIND11_NOINLINE inline std::string error_string() {
if (!PyErr_Occurred()) {
PyErr_SetString(PyExc_RuntimeError, "Unknown internal error occurred");
return "Unknown internal error occurred";
}
error_scope scope; // Preserve error state
std::string errorString;
if (scope.type) {
errorString += handle(scope.type).attr("__name__").cast<std::string>();
errorString += ": ";
}
if (scope.value)
errorString += (std::string) str(scope.value);
PyErr_NormalizeException(&scope.type, &scope.value, &scope.trace);
#if PY_MAJOR_VERSION >= 3
if (scope.trace != nullptr)
PyException_SetTraceback(scope.value, scope.trace);
#endif
#if !defined(PYPY_VERSION)
if (scope.trace) {
PyTracebackObject *trace = (PyTracebackObject *) scope.trace;
/* Get the deepest trace possible */
while (trace->tb_next)
trace = trace->tb_next;
PyFrameObject *frame = trace->tb_frame;
errorString += "\n\nAt:\n";
while (frame) {
int lineno = PyFrame_GetLineNumber(frame);
errorString +=
" " + handle(frame->f_code->co_filename).cast<std::string>() +
"(" + std::to_string(lineno) + "): " +
handle(frame->f_code->co_name).cast<std::string>() + "\n";
frame = frame->f_back;
}
trace = trace->tb_next;
}
#endif
return errorString;
}
PYBIND11_NOINLINE inline handle get_object_handle(const void *ptr, const detail::type_info *type ) {
auto &instances = get_internals().registered_instances;
auto range = instances.equal_range(ptr);
for (auto it = range.first; it != range.second; ++it) {
auto instance_type = detail::get_type_info(Py_TYPE(it->second));
if (instance_type && instance_type == type)
return handle((PyObject *) it->second);
}
return handle();
}
inline PyThreadState *get_thread_state_unchecked() {
#if defined(PYPY_VERSION)
return PyThreadState_GET();
#elif PY_VERSION_HEX < 0x03000000
return _PyThreadState_Current;
#elif PY_VERSION_HEX < 0x03050000
return (PyThreadState*) _Py_atomic_load_relaxed(&_PyThreadState_Current);
#elif PY_VERSION_HEX < 0x03050200
return (PyThreadState*) _PyThreadState_Current.value;
#else
return _PyThreadState_UncheckedGet();
#endif
}
// Forward declaration
inline void keep_alive_impl(handle nurse, handle patient);
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)
return false;
return load(src, convert, Py_TYPE(src.ptr()));
}
bool load(handle src, bool convert, PyTypeObject *tobj) {
if (!src || !typeinfo)
return false;
if (src.is_none()) {
value = nullptr;
return true;
}
if (typeinfo->simple_type) { /* Case 1: no multiple inheritance etc. involved */
/* Check if we can safely perform a reinterpret-style cast */
if (PyType_IsSubtype(tobj, typeinfo->type)) {
value = reinterpret_cast<instance<void> *>(src.ptr())->value;
return true;
}
} else { /* Case 2: multiple inheritance */
/* Check if we can safely perform a reinterpret-style cast */
if (tobj == typeinfo->type) {
value = reinterpret_cast<instance<void> *>(src.ptr())->value;
return true;
}
/* If this is a python class, also check the parents recursively */
auto const &type_dict = get_internals().registered_types_py;
bool new_style_class = PyType_Check((PyObject *) tobj);
if (type_dict.find(tobj) == type_dict.end() && new_style_class && tobj->tp_bases) {
auto parents = reinterpret_borrow<tuple>(tobj->tp_bases);
for (handle parent : parents) {
bool result = load(src, convert, (PyTypeObject *) parent.ptr());
if (result)
return true;
}
}
/* Try implicit casts */
for (auto &cast : typeinfo->implicit_casts) {
type_caster_generic sub_caster(*cast.first);
if (sub_caster.load(src, convert)) {
value = cast.second(sub_caster.value);
return true;
}
}
}
/* Perform an implicit conversion */
if (convert) {
for (auto &converter : typeinfo->implicit_conversions) {
temp = reinterpret_steal<object>(converter(src.ptr(), typeinfo->type));
if (load(temp, false))
return true;
}
for (auto &converter : *typeinfo->direct_conversions) {
if (converter(src.ptr(), value))
return true;
}
}
return false;
}
PYBIND11_NOINLINE static handle cast(const void *_src, return_value_policy policy, handle parent,
const std::type_info *type_info,
const std::type_info *type_info_backup,
void *(*copy_constructor)(const void *),
void *(*move_constructor)(const void *),
const void *existing_holder = nullptr) {
void *src = const_cast<void *>(_src);
if (src == nullptr)
return none().inc_ref();
auto &internals = get_internals();
auto it = internals.registered_types_cpp.find(std::type_index(*type_info));
if (it == internals.registered_types_cpp.end()) {
type_info = type_info_backup;
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;
auto it_instances = internals.registered_instances.equal_range(src);
for (auto it_i = it_instances.first; it_i != it_instances.second; ++it_i) {
auto instance_type = detail::get_type_info(Py_TYPE(it_i->second));
if (instance_type && instance_type == tinfo)
return handle((PyObject *) it_i->second).inc_ref();
}
auto inst = reinterpret_steal<object>(PyType_GenericAlloc(tinfo->type, 0));
auto wrapper = (instance<void> *) inst.ptr();
wrapper->value = nullptr;
wrapper->owned = false;
switch (policy) {
case return_value_policy::automatic:
case return_value_policy::take_ownership:
wrapper->value = src;
wrapper->owned = true;
break;
case return_value_policy::automatic_reference:
case return_value_policy::reference:
wrapper->value = src;
wrapper->owned = false;
break;
case return_value_policy::copy:
if (copy_constructor)
wrapper->value = copy_constructor(src);
else
throw cast_error("return_value_policy = copy, but the "
"object is non-copyable!");
wrapper->owned = true;
break;
case return_value_policy::move:
if (move_constructor)
wrapper->value = move_constructor(src);
else if (copy_constructor)
wrapper->value = copy_constructor(src);
else
throw cast_error("return_value_policy = move, but the "
"object is neither movable nor copyable!");
wrapper->owned = true;
break;
case return_value_policy::reference_internal:
wrapper->value = src;
wrapper->owned = false;
detail::keep_alive_impl(inst, parent);
break;
default:
throw cast_error("unhandled return_value_policy: should not happen!");
}
tinfo->init_holder(inst.ptr(), existing_holder);
internals.registered_instances.emplace(wrapper->value, inst.ptr());
return inst.release();
}
protected:
const type_info *typeinfo = nullptr;
void *value = nullptr;
object temp;
};
/* Determine suitable casting operator */
template <typename T>
using cast_op_type = typename std::conditional<std::is_pointer<typename std::remove_reference<T>::type>::value,
typename std::add_pointer<intrinsic_t<T>>::type,
typename std::add_lvalue_reference<intrinsic_t<T>>::type>::type;
// std::is_copy_constructible isn't quite enough: it lets std::vector<T> (and similar) through when
// T is non-copyable, but code containing such a copy constructor fails to actually compile.
template <typename T, typename SFINAE = void> struct is_copy_constructible : std::is_copy_constructible<T> {};
// Specialization for types that appear to be copy constructible but also look like stl containers
// (we specifically check for: has `value_type` and `reference` with `reference = value_type&`): if
// so, copy constructability depends on whether the value_type is copy constructible.
template <typename Container> struct is_copy_constructible<Container, enable_if_t<
std::is_copy_constructible<Container>::value &&
std::is_same<typename Container::value_type &, typename Container::reference>::value
>> : std::is_copy_constructible<typename Container::value_type> {};
/// Generic type caster for objects stored on the heap
template <typename type> class type_caster_base : public type_caster_generic {
using itype = intrinsic_t<type>;
public:
static PYBIND11_DESCR name() { return type_descr(_<type>()); }
type_caster_base() : type_caster_base(typeid(type)) { }
explicit type_caster_base(const std::type_info &info) : type_caster_generic(info) { }
static handle cast(const itype &src, return_value_policy policy, handle parent) {
if (policy == return_value_policy::automatic || policy == return_value_policy::automatic_reference)
policy = return_value_policy::copy;
return cast(&src, policy, parent);
}
static handle cast(itype &&src, return_value_policy, handle parent) {
return cast(&src, return_value_policy::move, parent);
}
static handle cast(const itype *src, return_value_policy policy, handle parent) {
return type_caster_generic::cast(
src, policy, parent, src ? &typeid(*src) : nullptr, &typeid(type),
make_copy_constructor(src), make_move_constructor(src));
}
static handle cast_holder(const itype *src, const void *holder) {
return type_caster_generic::cast(
src, return_value_policy::take_ownership, {},
src ? &typeid(*src) : nullptr, &typeid(type),
nullptr, nullptr, holder);
}
template <typename T> using cast_op_type = pybind11::detail::cast_op_type<T>;
operator itype*() { return (type *) value; }
operator itype&() { if (!value) throw reference_cast_error(); return *((itype *) value); }
protected:
typedef void *(*Constructor)(const void *stream);
#if !defined(_MSC_VER)
/* Only enabled when the types are {copy,move}-constructible *and* when the type
does not have a private operator new implementaton. */
template <typename T = type, typename = enable_if_t<is_copy_constructible<T>::value>> static auto make_copy_constructor(const T *value) -> decltype(new T(*value), Constructor(nullptr)) {
return [](const void *arg) -> void * { return new T(*((const T *) arg)); }; }
template <typename T = type> static auto make_move_constructor(const T *value) -> decltype(new T(std::move(*((T *) value))), Constructor(nullptr)) {
return [](const void *arg) -> void * { return (void *) new T(std::move(*const_cast<T *>(reinterpret_cast<const T *>(arg)))); }; }
#else
/* Visual Studio 2015's SFINAE implementation doesn't yet handle the above robustly in all situations.
Use a workaround that only tests for constructibility for now. */
template <typename T = type, typename = enable_if_t<is_copy_constructible<T>::value>>
static Constructor make_copy_constructor(const T *value) {
return [](const void *arg) -> void * { return new T(*((const T *)arg)); }; }
template <typename T = type, typename = enable_if_t<std::is_move_constructible<T>::value>>
static Constructor make_move_constructor(const T *value) {
return [](const void *arg) -> void * { return (void *) new T(std::move(*((T *)arg))); }; }
#endif
static Constructor make_copy_constructor(...) { return nullptr; }
static Constructor make_move_constructor(...) { return nullptr; }
};
template <typename type, typename SFINAE = void> class type_caster : public type_caster_base<type> { };
template <typename type> using make_caster = type_caster<intrinsic_t<type>>;
// Shortcut for calling a caster's `cast_op_type` cast operator for casting a type_caster to a T
template <typename T> typename make_caster<T>::template cast_op_type<T> cast_op(make_caster<T> &caster) {
return caster.operator typename make_caster<T>::template cast_op_type<T>();
}
template <typename T> typename make_caster<T>::template cast_op_type<T> cast_op(make_caster<T> &&caster) {
return cast_op<T>(caster);
}
template <typename type> class type_caster<std::reference_wrapper<type>> : public type_caster_base<type> {
public:
static handle cast(const std::reference_wrapper<type> &src, return_value_policy policy, handle parent) {
return type_caster_base<type>::cast(&src.get(), policy, parent);
}
template <typename T> using cast_op_type = std::reference_wrapper<type>;
operator std::reference_wrapper<type>() { return std::ref(*((type *) this->value)); }
};
#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; } \
template <typename _T> using cast_op_type = pybind11::detail::cast_op_type<_T>
template <typename CharT> using is_std_char_type = any_of<
std::is_same<CharT, char>, /* std::string */
std::is_same<CharT, char16_t>, /* std::u16string */
std::is_same<CharT, char32_t>, /* std::u32string */
std::is_same<CharT, wchar_t> /* std::wstring */
>;
template <typename T>
struct type_caster<T, enable_if_t<std::is_arithmetic<T>::value && !is_std_char_type<T>::value>> {
using _py_type_0 = conditional_t<sizeof(T) <= sizeof(long), long, long long>;
using _py_type_1 = conditional_t<std::is_signed<T>::value, _py_type_0, typename std::make_unsigned<_py_type_0>::type>;
using py_type = conditional_t<std::is_floating_point<T>::value, double, _py_type_1>;
public:
bool load(handle src, bool convert) {
py_type py_value;
if (!src)
return false;
if (std::is_floating_point<T>::value) {
if (convert || PyFloat_Check(src.ptr()))
py_value = (py_type) PyFloat_AsDouble(src.ptr());
else
return false;
} else if (sizeof(T) <= sizeof(long)) {
if (PyFloat_Check(src.ptr()))
return false;
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 (PyFloat_Check(src.ptr()))
return false;
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()))) {
#if PY_VERSION_HEX < 0x03000000
bool type_error = PyErr_ExceptionMatches(PyExc_SystemError);
#else
bool type_error = PyErr_ExceptionMatches(PyExc_TypeError);
#endif
PyErr_Clear();
if (type_error && convert && PyNumber_Check(src.ptr())) {
auto tmp = reinterpret_borrow<object>(std::is_floating_point<T>::value
? PyNumber_Float(src.ptr())
: PyNumber_Long(src.ptr()));
PyErr_Clear();
return load(tmp, false);
}
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);
}
}
PYBIND11_TYPE_CASTER(T, _<std::is_integral<T>::value>("int", "float"));
};
template<typename T> struct void_caster {
public:
bool load(handle, bool) { return false; }
static handle cast(T, return_value_policy /* policy */, handle /* parent */) {
return none().inc_ref();
}
PYBIND11_TYPE_CASTER(T, _("None"));
};
template <> class type_caster<void_type> : public void_caster<void_type> {};
template <> class type_caster<void> : public type_caster<void_type> {
public:
using type_caster<void_type>::cast;
bool load(handle h, bool) {
if (!h) {
return false;
} else if (h.is_none()) {
value = nullptr;
return true;
}
/* Check if this is a capsule */
if (isinstance<capsule>(h)) {
value = reinterpret_borrow<capsule>(h);
return true;
}
/* Check if this is a C++ type */
if (get_type_info((PyTypeObject *) h.get_type().ptr())) {
value = ((instance<void> *) h.ptr())->value;
return true;
}
/* Fail */
return false;
}
static handle cast(const void *ptr, return_value_policy /* policy */, handle /* parent */) {
if (ptr)
return capsule(ptr).release();
else
return none().inc_ref();
}
template <typename T> using cast_op_type = void*&;
operator void *&() { return value; }
static PYBIND11_DESCR name() { return type_descr(_("capsule")); }
private:
void *value = nullptr;
};
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) return false;
else 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"));
};
// Helper class for UTF-{8,16,32} C++ stl strings:
template <typename CharT, class Traits, class Allocator>
struct type_caster<std::basic_string<CharT, Traits, Allocator>, enable_if_t<is_std_char_type<CharT>::value>> {
// Simplify life by being able to assume standard char sizes (the standard only guarantees
// minimums), but Python requires exact sizes
static_assert(!std::is_same<CharT, char>::value || sizeof(CharT) == 1, "Unsupported char size != 1");
static_assert(!std::is_same<CharT, char16_t>::value || sizeof(CharT) == 2, "Unsupported char16_t size != 2");
static_assert(!std::is_same<CharT, char32_t>::value || sizeof(CharT) == 4, "Unsupported char32_t size != 4");
// wchar_t can be either 16 bits (Windows) or 32 (everywhere else)
static_assert(!std::is_same<CharT, wchar_t>::value || sizeof(CharT) == 2 || sizeof(CharT) == 4,
"Unsupported wchar_t size != 2/4");
static constexpr size_t UTF_N = 8 * sizeof(CharT);
static constexpr const char *encoding = UTF_N == 8 ? "utf8" : UTF_N == 16 ? "utf16" : "utf32";
using StringType = std::basic_string<CharT, Traits, Allocator>;
bool load(handle src, bool) {
#if PY_MAJOR_VERSION < 3
object temp;
#endif
handle load_src = src;
if (!src) {
return false;
} else if (!PyUnicode_Check(load_src.ptr())) {
#if PY_MAJOR_VERSION >= 3
return false;
// The below is a guaranteed failure in Python 3 when PyUnicode_Check returns false
#else
if (!PYBIND11_BYTES_CHECK(load_src.ptr()))
return false;
temp = reinterpret_steal<object>(PyUnicode_FromObject(load_src.ptr()));
if (!temp) { PyErr_Clear(); return false; }
load_src = temp;
#endif
}
object utfNbytes = reinterpret_steal<object>(PyUnicode_AsEncodedString(
load_src.ptr(), encoding, nullptr));
if (!utfNbytes) { PyErr_Clear(); return false; }
const CharT *buffer = reinterpret_cast<const CharT *>(PYBIND11_BYTES_AS_STRING(utfNbytes.ptr()));
size_t length = (size_t) PYBIND11_BYTES_SIZE(utfNbytes.ptr()) / sizeof(CharT);
if (UTF_N > 8) { buffer++; length--; } // Skip BOM for UTF-16/32
value = StringType(buffer, length);
return true;
}
static handle cast(const StringType &src, return_value_policy /* policy */, handle /* parent */) {
const char *buffer = reinterpret_cast<const char *>(src.c_str());
ssize_t nbytes = ssize_t(src.size() * sizeof(CharT));
handle s = PyUnicode_Decode(buffer, nbytes, encoding, nullptr);
if (!s) throw error_already_set();
return s;
}
PYBIND11_TYPE_CASTER(StringType, _(PYBIND11_STRING_NAME));
};
// Type caster for C-style strings. We basically use a std::string type caster, but also add the
// ability to use None as a nullptr char* (which the string caster doesn't allow).
template <typename CharT> struct type_caster<CharT, enable_if_t<is_std_char_type<CharT>::value>> {
using StringType = std::basic_string<CharT>;
using StringCaster = type_caster<StringType>;
StringCaster str_caster;
bool none = false;
public:
bool load(handle src, bool convert) {
if (!src) return false;
if (src.is_none()) {
// Defer accepting None to other overloads (if we aren't in convert mode):
if (!convert) return false;
none = true;
return true;
}
return str_caster.load(src, convert);
}
static handle cast(const CharT *src, return_value_policy policy, handle parent) {
if (src == nullptr) return pybind11::none().inc_ref();
return StringCaster::cast(StringType(src), policy, parent);
}
static handle cast(CharT src, return_value_policy policy, handle parent) {
if (std::is_same<char, CharT>::value) {
handle s = PyUnicode_DecodeLatin1((const char *) &src, 1, nullptr);
if (!s) throw error_already_set();
return s;
}
return StringCaster::cast(StringType(1, src), policy, parent);
}
operator CharT*() { return none ? nullptr : const_cast<CharT *>(static_cast<StringType &>(str_caster).c_str()); }
operator CharT() {
if (none)
throw value_error("Cannot convert None to a character");
auto &value = static_cast<StringType &>(str_caster);
size_t str_len = value.size();
if (str_len == 0)
throw value_error("Cannot convert empty string to a character");
// If we're in UTF-8 mode, we have two possible failures: one for a unicode character that
// is too high, and one for multiple unicode characters (caught later), so we need to figure
// out how long the first encoded character is in bytes to distinguish between these two
// errors. We also allow want to allow unicode characters U+0080 through U+00FF, as those
// can fit into a single char value.
if (StringCaster::UTF_N == 8 && str_len > 1 && str_len <= 4) {
unsigned char v0 = static_cast<unsigned char>(value[0]);
size_t char0_bytes = !(v0 & 0x80) ? 1 : // low bits only: 0-127
(v0 & 0xE0) == 0xC0 ? 2 : // 0b110xxxxx - start of 2-byte sequence
(v0 & 0xF0) == 0xE0 ? 3 : // 0b1110xxxx - start of 3-byte sequence
4; // 0b11110xxx - start of 4-byte sequence
if (char0_bytes == str_len) {
// If we have a 128-255 value, we can decode it into a single char:
if (char0_bytes == 2 && (v0 & 0xFC) == 0xC0) { // 0x110000xx 0x10xxxxxx
return static_cast<CharT>(((v0 & 3) << 6) + (static_cast<unsigned char>(value[1]) & 0x3F));
}
// Otherwise we have a single character, but it's > U+00FF
throw value_error("Character code point not in range(0x100)");
}
}
// UTF-16 is much easier: we can only have a surrogate pair for values above U+FFFF, thus a
// surrogate pair with total length 2 instantly indicates a range error (but not a "your
// string was too long" error).
else if (StringCaster::UTF_N == 16 && str_len == 2) {
char16_t v0 = static_cast<char16_t>(value[0]);
if (v0 >= 0xD800 && v0 < 0xE000)
throw value_error("Character code point not in range(0x10000)");
}
if (str_len != 1)
throw value_error("Expected a character, but multi-character string found");
return value[0];
}
static PYBIND11_DESCR name() { return type_descr(_(PYBIND11_STRING_NAME)); }
template <typename _T> using cast_op_type = typename std::remove_reference<pybind11::detail::cast_op_type<_T>>::type;
};
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 (!isinstance<sequence>(src))
return false;
const auto seq = reinterpret_borrow<sequence>(src);
if (seq.size() != 2)
return false;
return first.load(seq[0], convert) && second.load(seq[1], convert);
}
static handle cast(const type &src, return_value_policy policy, handle parent) {
auto o1 = reinterpret_steal<object>(make_caster<T1>::cast(src.first, policy, parent));
auto o2 = reinterpret_steal<object>(make_caster<T2>::cast(src.second, policy, parent));
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(
_("Tuple[") + make_caster<T1>::name() + _(", ") + make_caster<T2>::name() + _("]")
);
}
template <typename T> using cast_op_type = type;
operator type() {
return type(cast_op<T1>(first), cast_op<T2>(second));
}
protected:
make_caster<T1> first;
make_caster<T2> second;
};
template <typename... Tuple> class type_caster<std::tuple<Tuple...>> {
using type = std::tuple<Tuple...>;
using indices = make_index_sequence<sizeof...(Tuple)>;
static constexpr auto size = sizeof...(Tuple);
public:
bool load(handle src, bool convert) {
if (!isinstance<sequence>(src))
return false;
const auto seq = reinterpret_borrow<sequence>(src);
if (seq.size() != size)
return false;
return load_impl(seq, convert, indices{});
}
static handle cast(const type &src, return_value_policy policy, handle parent) {
return cast_impl(src, policy, parent, indices{});
}
static PYBIND11_DESCR name() {
return type_descr(_("Tuple[") + detail::concat(make_caster<Tuple>::name()...) + _("]"));
}
template <typename T> using cast_op_type = type;
operator type() { return implicit_cast(indices{}); }
protected:
template <size_t... Is>
type implicit_cast(index_sequence<Is...>) { return type(cast_op<Tuple>(std::get<Is>(value))...); }
static constexpr bool load_impl(const sequence &, bool, index_sequence<>) { return true; }
template <size_t... Is>
bool load_impl(const sequence &seq, bool convert, index_sequence<Is...>) {
for (bool r : {std::get<Is>(value).load(seq[Is], convert)...})
if (!r)
return false;
return true;
}
static handle cast_impl(const type &, return_value_policy, handle,
index_sequence<>) { return tuple().release(); }
/* Implementation: Convert a C++ tuple into a Python tuple */
template <size_t... Is>
static handle cast_impl(const type &src, return_value_policy policy, handle parent, index_sequence<Is...>) {
std::array<object, size> entries {{
reinterpret_steal<object>(make_caster<Tuple>::cast(std::get<Is>(src), policy, parent))...
}};
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();
}
std::tuple<make_caster<Tuple>...> value;
};
/// Helper class which abstracts away certain actions. Users can provide specializations for
/// custom holders, but it's only necessary if the type has a non-standard interface.
template <typename T>
struct holder_helper {
static auto get(const T &p) -> decltype(p.get()) { return p.get(); }
};
/// Type caster for holder types like std::shared_ptr, etc.
template <typename type, typename holder_type>
struct copyable_holder_caster : public type_caster_base<type> {
public:
using base = type_caster_base<type>;
using base::base;
using base::cast;
using base::typeinfo;
using base::value;
using base::temp;
PYBIND11_NOINLINE bool load(handle src, bool convert) {
return load(src, convert, Py_TYPE(src.ptr()));
}
bool load(handle src, bool convert, PyTypeObject *tobj) {
if (!src || !typeinfo)
return false;
if (src.is_none()) {
value = nullptr;
return true;
}
if (typeinfo->simple_type) { /* Case 1: no multiple inheritance etc. involved */
/* Check if we can safely perform a reinterpret-style cast */
if (PyType_IsSubtype(tobj, typeinfo->type))
return load_value_and_holder(src);
} else { /* Case 2: multiple inheritance */
/* Check if we can safely perform a reinterpret-style cast */
if (tobj == typeinfo->type)
return load_value_and_holder(src);
/* If this is a python class, also check the parents recursively */
auto const &type_dict = get_internals().registered_types_py;
bool new_style_class = PyType_Check((PyObject *) tobj);
if (type_dict.find(tobj) == type_dict.end() && new_style_class && tobj->tp_bases) {
auto parents = reinterpret_borrow<tuple>(tobj->tp_bases);
for (handle parent : parents) {
bool result = load(src, convert, (PyTypeObject *) parent.ptr());
if (result)
return true;
}
}
if (try_implicit_casts(src, convert))
return true;
}
if (convert) {
for (auto &converter : typeinfo->implicit_conversions) {
temp = reinterpret_steal<object>(converter(src.ptr(), typeinfo->type));
if (load(temp, false))
return true;
}
}
return false;
}
bool load_value_and_holder(handle src) {
auto inst = (instance<type, holder_type> *) src.ptr();
value = (void *) inst->value;
if (inst->holder_constructed) {
holder = inst->holder;
return true;
} else {
throw cast_error("Unable to cast from non-held to held instance (T& to Holder<T>) "
#if defined(NDEBUG)
"(compile in debug mode for type information)");
#else
"of type '" + type_id<holder_type>() + "''");
#endif
}
}
template <typename T = holder_type, detail::enable_if_t<!std::is_constructible<T, const T &, type*>::value, int> = 0>
bool try_implicit_casts(handle, bool) { return false; }
template <typename T = holder_type, detail::enable_if_t<std::is_constructible<T, const T &, type*>::value, int> = 0>
bool try_implicit_casts(handle src, bool convert) {
for (auto &cast : typeinfo->implicit_casts) {
copyable_holder_caster sub_caster(*cast.first);
if (sub_caster.load(src, convert)) {
value = cast.second(sub_caster.value);
holder = holder_type(sub_caster.holder, (type *) value);
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, handle) {
const auto *ptr = holder_helper<holder_type>::get(src);
return type_caster_base<type>::cast_holder(ptr, &src);
}
protected:
holder_type holder;
};
/// Specialize for the common std::shared_ptr, so users don't need to
template <typename T>
class type_caster<std::shared_ptr<T>> : public copyable_holder_caster<T, std::shared_ptr<T>> { };
template <typename type, typename holder_type>
struct move_only_holder_caster {
static handle cast(holder_type &&src, return_value_policy, handle) {
auto *ptr = holder_helper<holder_type>::get(src);
return type_caster_base<type>::cast_holder(ptr, &src);
}
static PYBIND11_DESCR name() { return type_caster_base<type>::name(); }
};
template <typename type, typename deleter>
class type_caster<std::unique_ptr<type, deleter>>
: public move_only_holder_caster<type, std::unique_ptr<type, deleter>> { };
template <typename type, typename holder_type>
using type_caster_holder = conditional_t<std::is_copy_constructible<holder_type>::value,
copyable_holder_caster<type, holder_type>,
move_only_holder_caster<type, holder_type>>;
template <typename T, bool Value = false> struct always_construct_holder { static constexpr bool value = Value; };
/// Create a specialization for custom holder types (silently ignores std::shared_ptr)
#define PYBIND11_DECLARE_HOLDER_TYPE(type, holder_type, ...) \
namespace pybind11 { namespace detail { \
template <typename type> \
struct always_construct_holder<holder_type> : always_construct_holder<void, ##__VA_ARGS__> { }; \
template <typename type> \
class type_caster<holder_type, enable_if_t<!is_shared_ptr<holder_type>::value>> \
: public type_caster_holder<type, holder_type> { }; \
}}
// PYBIND11_DECLARE_HOLDER_TYPE holder types:
template <typename base, typename holder> struct is_holder_type :
std::is_base_of<detail::type_caster_holder<base, holder>, detail::type_caster<holder>> {};
// Specialization for always-supported unique_ptr holders:
template <typename base, typename deleter> struct is_holder_type<base, std::unique_ptr<base, deleter>> :
std::true_type {};
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 <> struct handle_type_name<args> { static PYBIND11_DESCR name() { return _("*args"); } };
template <> struct handle_type_name<kwargs> { static PYBIND11_DESCR name() { return _("**kwargs"); } };
template <typename type>
struct pyobject_caster {
template <typename T = type, enable_if_t<std::is_same<T, handle>::value, int> = 0>
bool load(handle src, bool /* convert */) { value = src; return static_cast<bool>(value); }
template <typename T = type, enable_if_t<std::is_base_of<object, T>::value, int> = 0>
bool load(handle src, bool /* convert */) {
if (!isinstance<type>(src))
return false;
value = reinterpret_borrow<type>(src);
return true;
}
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());
};
template <typename T>
class type_caster<T, enable_if_t<is_pyobject<T>::value>> : public pyobject_caster<T> { };
// Our conditions for enabling moving are quite restrictive:
// At compile time:
// - T needs to be a non-const, non-pointer, non-reference type
// - type_caster<T>::operator T&() must exist
// - the type must be move constructible (obviously)
// At run-time:
// - if the type is non-copy-constructible, the object must be the sole owner of the type (i.e. it
// must have ref_count() == 1)h
// If any of the above are not satisfied, we fall back to copying.
template <typename T> using move_is_plain_type = satisfies_none_of<T,
std::is_void, std::is_pointer, std::is_reference, std::is_const
>;
template <typename T, typename SFINAE = void> struct move_always : std::false_type {};
template <typename T> struct move_always<T, enable_if_t<all_of<
move_is_plain_type<T>,
negation<std::is_copy_constructible<T>>,
std::is_move_constructible<T>,
std::is_same<decltype(std::declval<make_caster<T>>().operator T&()), T&>
>::value>> : std::true_type {};
template <typename T, typename SFINAE = void> struct move_if_unreferenced : std::false_type {};
template <typename T> struct move_if_unreferenced<T, enable_if_t<all_of<
move_is_plain_type<T>,
negation<move_always<T>>,
std::is_move_constructible<T>,
std::is_same<decltype(std::declval<make_caster<T>>().operator T&()), T&>
>::value>> : std::true_type {};
template <typename T> using move_never = none_of<move_always<T>, move_if_unreferenced<T>>;
// Detect whether returning a `type` from a cast on type's type_caster is going to result in a
// reference or pointer to a local variable of the type_caster. Basically, only
// non-reference/pointer `type`s and reference/pointers from a type_caster_generic are safe;
// everything else returns a reference/pointer to a local variable.
template <typename type> using cast_is_temporary_value_reference = bool_constant<
(std::is_reference<type>::value || std::is_pointer<type>::value) &&
!std::is_base_of<type_caster_generic, make_caster<type>>::value
>;
// When a value returned from a C++ function is being cast back to Python, we almost always want to
// force `policy = move`, regardless of the return value policy the function/method was declared
// with. Some classes (most notably Eigen::Ref and related) need to avoid this, and so can do so by
// specializing this struct.
template <typename Return, typename SFINAE = void> struct return_value_policy_override {
static return_value_policy policy(return_value_policy p) {
return !std::is_lvalue_reference<Return>::value && !std::is_pointer<Return>::value
? return_value_policy::move : p;
}
};
// Basic python -> C++ casting; throws if casting fails
template <typename T, typename SFINAE> type_caster<T, SFINAE> &load_type(type_caster<T, SFINAE> &conv, const handle &handle) {
if (!conv.load(handle, true)) {
#if defined(NDEBUG)
throw cast_error("Unable to cast Python instance to C++ type (compile in debug mode for details)");
#else
throw cast_error("Unable to cast Python instance of type " +
(std::string) str(handle.get_type()) + " to C++ type '" + type_id<T>() + "''");
#endif
}
return conv;
}
// Wrapper around the above that also constructs and returns a type_caster
template <typename T> make_caster<T> load_type(const handle &handle) {
make_caster<T> conv;
load_type(conv, handle);
return conv;
}
NAMESPACE_END(detail)
// pytype -> C++ type
template <typename T, detail::enable_if_t<!detail::is_pyobject<T>::value, int> = 0>
T cast(const handle &handle) {
using namespace detail;
static_assert(!cast_is_temporary_value_reference<T>::value,
"Unable to cast type to reference: value is local to type caster");
return cast_op<T>(load_type<T>(handle));
}
// pytype -> pytype (calls converting constructor)
template <typename T, detail::enable_if_t<detail::is_pyobject<T>::value, int> = 0>
T cast(const handle &handle) { return T(reinterpret_borrow<object>(handle)); }
// C++ type -> py::object
template <typename T, detail::enable_if_t<!detail::is_pyobject<T>::value, int> = 0>
object cast(const T &value, return_value_policy policy = return_value_policy::automatic_reference,
handle parent = handle()) {
if (policy == return_value_policy::automatic)
policy = std::is_pointer<T>::value ? return_value_policy::take_ownership : return_value_policy::copy;
else if (policy == return_value_policy::automatic_reference)
policy = std::is_pointer<T>::value ? return_value_policy::reference : return_value_policy::copy;
return reinterpret_steal<object>(detail::make_caster<T>::cast(value, policy, parent));
}
template <typename T> T handle::cast() const { return pybind11::cast<T>(*this); }
template <> inline void handle::cast() const { return; }
template <typename T>
detail::enable_if_t<!detail::move_never<T>::value, T> move(object &&obj) {
if (obj.ref_count() > 1)
#if defined(NDEBUG)
throw cast_error("Unable to cast Python instance to C++ rvalue: instance has multiple references"
" (compile in debug mode for details)");
#else
throw cast_error("Unable to move from Python " + (std::string) str(obj.get_type()) +
" instance to C++ " + type_id<T>() + " instance: instance has multiple references");
#endif
// Move into a temporary and return that, because the reference may be a local value of `conv`
T ret = std::move(detail::load_type<T>(obj).operator T&());
return ret;
}
// Calling cast() on an rvalue calls pybind::cast with the object rvalue, which does:
// - If we have to move (because T has no copy constructor), do it. This will fail if the moved
// object has multiple references, but trying to copy will fail to compile.
// - If both movable and copyable, check ref count: if 1, move; otherwise copy
// - Otherwise (not movable), copy.
template <typename T> detail::enable_if_t<detail::move_always<T>::value, T> cast(object &&object) {
return move<T>(std::move(object));
}
template <typename T> detail::enable_if_t<detail::move_if_unreferenced<T>::value, T> cast(object &&object) {
if (object.ref_count() > 1)
return cast<T>(object);
else
return move<T>(std::move(object));
}
template <typename T> detail::enable_if_t<detail::move_never<T>::value, T> cast(object &&object) {
return cast<T>(object);
}
template <typename T> T object::cast() const & { return pybind11::cast<T>(*this); }
template <typename T> T object::cast() && { return pybind11::cast<T>(std::move(*this)); }
template <> inline void object::cast() const & { return; }
template <> inline void object::cast() && { return; }
NAMESPACE_BEGIN(detail)
// Declared in pytypes.h:
template <typename T, enable_if_t<!is_pyobject<T>::value, int>>
object object_or_cast(T &&o) { return pybind11::cast(std::forward<T>(o)); }
struct overload_unused {}; // Placeholder type for the unneeded (and dead code) static variable in the OVERLOAD_INT macro
template <typename ret_type> using overload_caster_t = conditional_t<
cast_is_temporary_value_reference<ret_type>::value, make_caster<ret_type>, overload_unused>;
// Trampoline use: for reference/pointer types to value-converted values, we do a value cast, then
// store the result in the given variable. For other types, this is a no-op.
template <typename T> enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&o, make_caster<T> &caster) {
return cast_op<T>(load_type(caster, o));
}
template <typename T> enable_if_t<!cast_is_temporary_value_reference<T>::value, T> cast_ref(object &&, overload_unused &) {
pybind11_fail("Internal error: cast_ref fallback invoked"); }
// Trampoline use: Having a pybind11::cast with an invalid reference type is going to static_assert, even
// though if it's in dead code, so we provide a "trampoline" to pybind11::cast that only does anything in
// cases where pybind11::cast is valid.
template <typename T> enable_if_t<!cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&o) {
return pybind11::cast<T>(std::move(o)); }
template <typename T> enable_if_t<cast_is_temporary_value_reference<T>::value, T> cast_safe(object &&) {
pybind11_fail("Internal error: cast_safe fallback invoked"); }
template <> inline void cast_safe<void>(object &&) {}
NAMESPACE_END(detail)
template <return_value_policy policy = return_value_policy::automatic_reference,
typename... Args> tuple make_tuple(Args&&... args_) {
const size_t size = sizeof...(Args);
std::array<object, size> args {
{ reinterpret_steal<object>(detail::make_caster<Args>::cast(
std::forward<Args>(args_), policy, nullptr))... }
};
for (auto &arg_value : args) {
if (!arg_value) {
#if defined(NDEBUG)
throw cast_error("make_tuple(): unable to convert arguments to Python object (compile in debug mode for details)");
#else
throw cast_error("make_tuple(): unable to convert arguments of types '" +
(std::string) type_id<std::tuple<Args...>>() + "' to Python object");
#endif
}
}
tuple result(size);
int counter = 0;
for (auto &arg_value : args)
PyTuple_SET_ITEM(result.ptr(), counter++, arg_value.release().ptr());
return result;
}
/// \ingroup annotations
/// Annotation for arguments
struct arg {
/// Constructs an argument with the name of the argument; if null or omitted, this is a positional argument.
constexpr explicit arg(const char *name = nullptr) : name(name), flag_noconvert(false) { }
/// Assign a value to this argument
template <typename T> arg_v operator=(T &&value) const;
/// Indicate that the type should not be converted in the type caster
arg &noconvert(bool flag = true) { flag_noconvert = flag; return *this; }
const char *name; ///< If non-null, this is a named kwargs argument
bool flag_noconvert : 1; ///< If set, do not allow conversion (requires a supporting type caster!)
};
/// \ingroup annotations
/// Annotation for arguments with values
struct arg_v : arg {
private:
template <typename T>
arg_v(arg &&base, T &&x, const char *descr = nullptr)
: arg(base),
value(reinterpret_steal<object>(
detail::make_caster<T>::cast(x, return_value_policy::automatic, {})
)),
descr(descr)
#if !defined(NDEBUG)
, type(type_id<T>())
#endif
{ }
public:
/// Direct construction with name, default, and description
template <typename T>
arg_v(const char *name, T &&x, const char *descr = nullptr)
: arg_v(arg(name), std::forward<T>(x), descr) { }
/// Called internally when invoking `py::arg("a") = value`
template <typename T>
arg_v(const arg &base, T &&x, const char *descr = nullptr)
: arg_v(arg(base), std::forward<T>(x), descr) { }
/// Same as `arg::noconvert()`, but returns *this as arg_v&, not arg&
arg_v &noconvert(bool flag = true) { arg::noconvert(flag); return *this; }
/// The default value
object value;
/// The (optional) description of the default value
const char *descr;
#if !defined(NDEBUG)
/// The C++ type name of the default value (only available when compiled in debug mode)
std::string type;
#endif
};
template <typename T>
arg_v arg::operator=(T &&value) const { return {std::move(*this), std::forward<T>(value)}; }
/// Alias for backward compatibility -- to be removed in version 2.0
template <typename /*unused*/> using arg_t = arg_v;
inline namespace literals {
/** \rst
String literal version of `arg`
\endrst */
constexpr arg operator"" _a(const char *name, size_t) { return arg(name); }
}
NAMESPACE_BEGIN(detail)
// forward declaration
struct function_record;
/// Internal data associated with a single function call
struct function_call {
function_call(function_record &f, handle p); // Implementation in attr.h
/// The function data:
const function_record &func;
/// Arguments passed to the function:
std::vector<handle> args;
/// The `convert` value the arguments should be loaded with
std::vector<bool> args_convert;
/// The parent, if any
handle parent;
};
/// Helper class which loads arguments for C++ functions called from Python
template <typename... Args>
class argument_loader {
using indices = make_index_sequence<sizeof...(Args)>;
template <typename Arg> using argument_is_args = std::is_same<intrinsic_t<Arg>, args>;
template <typename Arg> using argument_is_kwargs = std::is_same<intrinsic_t<Arg>, kwargs>;
// Get args/kwargs argument positions relative to the end of the argument list:
static constexpr auto args_pos = constexpr_first<argument_is_args, Args...>() - (int) sizeof...(Args),
kwargs_pos = constexpr_first<argument_is_kwargs, Args...>() - (int) sizeof...(Args);
static constexpr bool args_kwargs_are_last = kwargs_pos >= - 1 && args_pos >= kwargs_pos - 1;
static_assert(args_kwargs_are_last, "py::args/py::kwargs are only permitted as the last argument(s) of a function");
public:
static constexpr bool has_kwargs = kwargs_pos < 0;
static constexpr bool has_args = args_pos < 0;
static PYBIND11_DESCR arg_names() { return detail::concat(make_caster<Args>::name()...); }
bool load_args(function_call &call) {
return load_impl_sequence(call, indices{});
}
template <typename Return, typename Func>
enable_if_t<!std::is_void<Return>::value, Return> call(Func &&f) {
return call_impl<Return>(std::forward<Func>(f), indices{});
}
template <typename Return, typename Func>
enable_if_t<std::is_void<Return>::value, void_type> call(Func &&f) {
call_impl<Return>(std::forward<Func>(f), indices{});
return void_type();
}
private:
static bool load_impl_sequence(function_call &, index_sequence<>) { return true; }
template <size_t... Is>
bool load_impl_sequence(function_call &call, index_sequence<Is...>) {
for (bool r : {std::get<Is>(value).load(call.args[Is], call.args_convert[Is])...})
if (!r)
return false;
return true;
}
template <typename Return, typename Func, size_t... Is>
Return call_impl(Func &&f, index_sequence<Is...>) {
return std::forward<Func>(f)(cast_op<Args>(std::get<Is>(value))...);
}
std::tuple<make_caster<Args>...> value;
};
/// Helper class which collects only positional arguments for a Python function call.
/// A fancier version below can collect any argument, but this one is optimal for simple calls.
template <return_value_policy policy>
class simple_collector {
public:
template <typename... Ts>
explicit simple_collector(Ts &&...values)
: m_args(pybind11::make_tuple<policy>(std::forward<Ts>(values)...)) { }
const tuple &args() const & { return m_args; }
dict kwargs() const { return {}; }
tuple args() && { return std::move(m_args); }
/// Call a Python function and pass the collected arguments
object call(PyObject *ptr) const {
PyObject *result = PyObject_CallObject(ptr, m_args.ptr());
if (!result)
throw error_already_set();
return reinterpret_steal<object>(result);
}
private:
tuple m_args;
};
/// Helper class which collects positional, keyword, * and ** arguments for a Python function call
template <return_value_policy policy>
class unpacking_collector {
public:
template <typename... Ts>
explicit unpacking_collector(Ts &&...values) {
// Tuples aren't (easily) resizable so a list is needed for collection,
// but the actual function call strictly requires a tuple.
auto args_list = list();
int _[] = { 0, (process(args_list, std::forward<Ts>(values)), 0)... };
ignore_unused(_);
m_args = std::move(args_list);
}
const tuple &args() const & { return m_args; }
const dict &kwargs() const & { return m_kwargs; }
tuple args() && { return std::move(m_args); }
dict kwargs() && { return std::move(m_kwargs); }
/// Call a Python function and pass the collected arguments
object call(PyObject *ptr) const {
PyObject *result = PyObject_Call(ptr, m_args.ptr(), m_kwargs.ptr());
if (!result)
throw error_already_set();
return reinterpret_steal<object>(result);
}
private:
template <typename T>
void process(list &args_list, T &&x) {
auto o = reinterpret_steal<object>(detail::make_caster<T>::cast(std::forward<T>(x), policy, {}));
if (!o) {
#if defined(NDEBUG)
argument_cast_error();
#else
argument_cast_error(std::to_string(args_list.size()), type_id<T>());
#endif
}
args_list.append(o);
}
void process(list &args_list, detail::args_proxy ap) {
for (const auto &a : ap)
args_list.append(a);
}
void process(list &/*args_list*/, arg_v a) {
if (!a.name)
#if defined(NDEBUG)
nameless_argument_error();
#else
nameless_argument_error(a.type);
#endif
if (m_kwargs.contains(a.name)) {
#if defined(NDEBUG)
multiple_values_error();
#else
multiple_values_error(a.name);
#endif
}
if (!a.value) {
#if defined(NDEBUG)
argument_cast_error();
#else
argument_cast_error(a.name, a.type);
#endif
}
m_kwargs[a.name] = a.value;
}
void process(list &/*args_list*/, detail::kwargs_proxy kp) {
if (!kp)
return;
for (const auto &k : reinterpret_borrow<dict>(kp)) {
if (m_kwargs.contains(k.first)) {
#if defined(NDEBUG)
multiple_values_error();
#else
multiple_values_error(str(k.first));
#endif
}
m_kwargs[k.first] = k.second;
}
}
[[noreturn]] static void nameless_argument_error() {
throw type_error("Got kwargs without a name; only named arguments "
"may be passed via py::arg() to a python function call. "
"(compile in debug mode for details)");
}
[[noreturn]] static void nameless_argument_error(std::string type) {
throw type_error("Got kwargs without a name of type '" + type + "'; only named "
"arguments may be passed via py::arg() to a python function call. ");
}
[[noreturn]] static void multiple_values_error() {
throw type_error("Got multiple values for keyword argument "
"(compile in debug mode for details)");
}
[[noreturn]] static void multiple_values_error(std::string name) {
throw type_error("Got multiple values for keyword argument '" + name + "'");
}
[[noreturn]] static void argument_cast_error() {
throw cast_error("Unable to convert call argument to Python object "
"(compile in debug mode for details)");
}
[[noreturn]] static void argument_cast_error(std::string name, std::string type) {
throw cast_error("Unable to convert call argument '" + name
+ "' of type '" + type + "' to Python object");
}
private:
tuple m_args;
dict m_kwargs;
};
/// Collect only positional arguments for a Python function call
template <return_value_policy policy, typename... Args,
typename = enable_if_t<all_of<is_positional<Args>...>::value>>
simple_collector<policy> collect_arguments(Args &&...args) {
return simple_collector<policy>(std::forward<Args>(args)...);
}
/// Collect all arguments, including keywords and unpacking (only instantiated when needed)
template <return_value_policy policy, typename... Args,
typename = enable_if_t<!all_of<is_positional<Args>...>::value>>
unpacking_collector<policy> collect_arguments(Args &&...args) {
// Following argument order rules for generalized unpacking according to PEP 448
static_assert(
constexpr_last<is_positional, Args...>() < constexpr_first<is_keyword_or_ds, Args...>()
&& constexpr_last<is_s_unpacking, Args...>() < constexpr_first<is_ds_unpacking, Args...>(),
"Invalid function call: positional args must precede keywords and ** unpacking; "
"* unpacking must precede ** unpacking"
);
return unpacking_collector<policy>(std::forward<Args>(args)...);
}
template <typename Derived>
template <return_value_policy policy, typename... Args>
object object_api<Derived>::operator()(Args &&...args) const {
return detail::collect_arguments<policy>(std::forward<Args>(args)...).call(derived().ptr());
}
template <typename Derived>
template <return_value_policy policy, typename... Args>
object object_api<Derived>::call(Args &&...args) const {
return operator()<policy>(std::forward<Args>(args)...);
}
NAMESPACE_END(detail)
#define PYBIND11_MAKE_OPAQUE(Type) \
namespace pybind11 { namespace detail { \
template<> class type_caster<Type> : public type_caster_base<Type> { }; \
}}
NAMESPACE_END(pybind11)
Reference in New Issue View Git Blame Copy Permalink