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pybind11/include/pybind/pybind.h
Wenzel Jakob 2ac80e77aa Better NumPy support
2015-07-22 01:00:06 +02:00

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/*
pybind/pybind.h: Main header file of the C++11 python binding generator library
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
#if defined(_MSC_VER)
#pragma warning(push)
#pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
#pragma warning(disable: 4800) // warning C4800: 'int': forcing value to bool 'true' or 'false' (performance warning)
#pragma warning(disable: 4996) // warning C4996: The POSIX name for this item is deprecated. Instead, use the ISO C and C++ conformant name
#pragma warning(disable: 4100) // warning C4100: Unreferenced formal parameter
#pragma warning(disable: 4512) // warning C4512: Assignment operator was implicitly defined as deleted
#endif
#include <pybind/cast.h>
NAMESPACE_BEGIN(pybind)
class cpp_function : public function {
public:
struct function_entry {
std::function<PyObject* (PyObject *)> impl;
std::string signature, doc;
bool is_constructor;
function_entry *next = nullptr;
};
cpp_function() { }
template <typename Func> cpp_function(
Func &&_func, const char *name = nullptr, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic,
function sibling = function(), bool is_method = false) {
/* Function traits extracted from the template type 'Func' */
typedef mpl::function_traits<Func> f_traits;
/* Suitable input and output casters */
typedef typename detail::type_caster<typename f_traits::args_type> cast_in;
typedef typename detail::type_caster<typename mpl::normalize_type<typename f_traits::return_type>::type> cast_out;
typename f_traits::f_type func = f_traits::cast(std::forward<Func>(_func));
auto impl = [func, policy](PyObject *pyArgs) -> PyObject *{
cast_in args;
if (!args.load(pyArgs, true))
return nullptr;
PyObject *parent = policy != return_value_policy::reference_internal
? nullptr : PyTuple_GetItem(pyArgs, 0);
return cast_out::cast(
f_traits::dispatch(func, args.operator typename f_traits::args_type()),
policy, parent);
};
initialize(name, doc, cast_in::name() + std::string(" -> ") + cast_out::name(),
sibling, is_method, std::move(impl));
}
private:
static PyObject *dispatcher(PyObject *self, PyObject *args, PyObject * /* kwargs */) {
function_entry *overloads = (function_entry *) PyCapsule_GetPointer(self, nullptr);
PyObject *result = nullptr;
try {
for (function_entry *it = overloads; it != nullptr; it = it->next) {
if ((result = it->impl(args)) != nullptr)
break;
}
} catch (const error_already_set &) { return nullptr;
} catch (const index_error &e) { PyErr_SetString(PyExc_IndexError, e.what()); return nullptr;
} catch (const stop_iteration &e) { PyErr_SetString(PyExc_StopIteration, e.what()); return nullptr;
} catch (const std::exception &e) { PyErr_SetString(PyExc_RuntimeError, e.what()); return nullptr;
} catch (...) {
PyErr_SetString(PyExc_RuntimeError, "Caught an unknown exception!");
return nullptr;
}
if (result) {
if (overloads->is_constructor) {
PyObject *inst = PyTuple_GetItem(args, 0);
const detail::type_info *type_info =
capsule(PyObject_GetAttrString((PyObject *) Py_TYPE(inst),
const_cast<char *>("__pybind__")), false);
type_info->init_holder(inst);
}
return result;
} else {
std::string signatures = "Incompatible function arguments. The "
"following argument types are supported:\n";
int ctr = 0;
for (function_entry *it = overloads; it != nullptr; it = it->next) {
signatures += " "+ std::to_string(++ctr) + ". ";
signatures += it->signature;
signatures += "\n";
}
PyErr_SetString(PyExc_TypeError, signatures.c_str());
return nullptr;
}
}
void initialize(const char *name, const char *doc,
const std::string &signature, function sibling,
bool is_method, std::function<PyObject *(PyObject *)> &&impl) {
if (name == nullptr)
name = "";
/* Linked list of function call handlers (for overloading) */
function_entry *entry = new function_entry();
entry->impl = std::move(impl);
entry->is_constructor = !strcmp(name, "__init__");
entry->signature = signature;
if (doc) entry->doc = doc;
if (!sibling.ptr() || !PyCFunction_Check(sibling.ptr())) {
PyMethodDef *def = new PyMethodDef();
memset(def, 0, sizeof(PyMethodDef));
def->ml_name = name != nullptr ? strdup(name) : name;
def->ml_meth = reinterpret_cast<PyCFunction>(*dispatcher);
def->ml_flags = METH_VARARGS | METH_KEYWORDS;
capsule entry_capsule(entry);
m_ptr = PyCFunction_New(def, entry_capsule.ptr());
if (!m_ptr)
throw std::runtime_error("cpp_function::cpp_function(): Could not allocate function object");
} else {
m_ptr = sibling.ptr();
inc_ref();
capsule entry_capsule(PyCFunction_GetSelf(m_ptr), true);
function_entry *parent = (function_entry *) entry_capsule, *backup = parent;
while (parent->next)
parent = parent->next;
parent->next = entry;
entry = backup;
}
std::string signatures;
int it = 0;
while (entry) { /* Create pydoc entry */
if (sibling.ptr())
signatures += std::to_string(++it) + ". ";
signatures += "Signature : " + std::string(entry->signature) + "\n";
if (!entry->doc.empty())
signatures += "\n" + std::string(entry->doc) + "\n";
if (entry->next)
signatures += "\n";
entry = entry->next;
}
PyCFunctionObject *func = (PyCFunctionObject *) m_ptr;
if (func->m_ml->ml_doc)
std::free((char *) func->m_ml->ml_doc);
func->m_ml->ml_doc = strdup(signatures.c_str());
if (is_method) {
m_ptr = PyInstanceMethod_New(m_ptr);
if (!m_ptr)
throw std::runtime_error("cpp_function::cpp_function(): Could not allocate instance method object");
Py_DECREF(func);
}
}
};
class cpp_method : public cpp_function {
public:
cpp_method () { }
template <typename Func>
cpp_method(Func &&_func, const char *name = nullptr, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic,
function sibling = function())
: cpp_function(std::forward<Func>(_func), name, doc, policy, sibling, true) { }
};
class module : public object {
public:
PYTHON_OBJECT_DEFAULT(module, object, PyModule_Check)
module(const char *name, const char *doc = nullptr) {
PyModuleDef *def = new PyModuleDef();
memset(def, 0, sizeof(PyModuleDef));
def->m_name = name;
def->m_doc = doc;
def->m_size = -1;
Py_INCREF(def);
m_ptr = PyModule_Create(def);
if (m_ptr == nullptr)
throw std::runtime_error("Internal error in module::module()");
inc_ref();
}
template <typename Func>
module &def(const char *name, Func f, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic) {
cpp_function func(f, name, doc, policy, (function) attr(name));
func.inc_ref(); /* The following line steals a reference to 'func' */
PyModule_AddObject(ptr(), name, func.ptr());
return *this;
}
module def_submodule(const char *name, const char *doc = nullptr) {
std::string full_name = std::string(PyModule_GetName(m_ptr))
+ std::string(".") + std::string(name);
module result(PyImport_AddModule(full_name.c_str()), true);
if (doc)
result.attr("__doc__") = pybind::str(doc);
attr(name) = result;
return result;
}
};
NAMESPACE_BEGIN(detail)
/* Forward declarations */
enum op_id : int;
enum op_type : int;
struct undefined_t;
template <op_id id, op_type ot, typename L = undefined_t, typename R = undefined_t> struct op_;
template <typename ... Args> struct init;
/// Basic support for creating new Python heap types
class custom_type : public object {
public:
PYTHON_OBJECT_DEFAULT(custom_type, object, PyType_Check)
custom_type(object &scope, const char *name_, const std::string &type_name,
size_t type_size, size_t instance_size,
void (*init_holder)(PyObject *), const destructor &dealloc,
PyObject *parent, const char *doc) {
PyHeapTypeObject *type = (PyHeapTypeObject*) PyType_Type.tp_alloc(&PyType_Type, 0);
PyObject *name = PyUnicode_FromString(name_);
if (type == nullptr || name == nullptr)
throw std::runtime_error("Internal error in custom_type::custom_type()");
Py_INCREF(name);
std::string full_name(name_);
pybind::str scope_name = (object) scope.attr("__name__"),
module_name = (object) scope.attr("__module__");
if (scope_name.check())
full_name = std::string(scope_name) + "." + full_name;
if (module_name.check())
full_name = std::string(module_name) + "." + full_name;
type->ht_name = type->ht_qualname = name;
type->ht_type.tp_name = strdup(full_name.c_str());
type->ht_type.tp_basicsize = instance_size;
type->ht_type.tp_init = (initproc) init;
type->ht_type.tp_new = (newfunc) new_instance;
type->ht_type.tp_dealloc = dealloc;
type->ht_type.tp_flags |=
Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HEAPTYPE;
type->ht_type.tp_flags &= ~Py_TPFLAGS_HAVE_GC;
type->ht_type.tp_as_number = &type->as_number;
type->ht_type.tp_as_sequence = &type->as_sequence;
type->ht_type.tp_as_mapping = &type->as_mapping;
type->ht_type.tp_base = (PyTypeObject *) parent;
Py_XINCREF(parent);
if (PyType_Ready(&type->ht_type) < 0)
throw std::runtime_error("Internal error in custom_type::custom_type()");
m_ptr = (PyObject *) type;
/* Needed by pydoc */
if (((module &) scope).check())
attr("__module__") = scope_name;
auto &type_info = detail::get_internals().registered_types[type_name];
type_info.type = (PyTypeObject *) m_ptr;
type_info.type_size = type_size;
type_info.init_holder = init_holder;
attr("__pybind__") = capsule(&type_info);
if (doc)
attr("__doc__") = pybind::str(doc);
scope.attr(name) = *this;
}
protected:
/* Allocate a metaclass on demand (for static properties) */
handle metaclass() {
auto &ht_type = ((PyHeapTypeObject *) m_ptr)->ht_type;
auto &ob_type = ht_type.ob_base.ob_base.ob_type;
if (ob_type == &PyType_Type) {
std::string name_ = std::string(ht_type.tp_name) + "_meta";
PyHeapTypeObject *type = (PyHeapTypeObject*) PyType_Type.tp_alloc(&PyType_Type, 0);
PyObject *name = PyUnicode_FromString(name_.c_str());
if (type == nullptr || name == nullptr)
throw std::runtime_error("Internal error in custom_type::metaclass()");
Py_INCREF(name);
type->ht_name = type->ht_qualname = name;
type->ht_type.tp_name = strdup(name_.c_str());
type->ht_type.tp_base = &PyType_Type;
type->ht_type.tp_flags |= Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HEAPTYPE;
type->ht_type.tp_flags &= ~Py_TPFLAGS_HAVE_GC;
if (PyType_Ready(&type->ht_type) < 0)
throw std::runtime_error("Internal error in custom_type::metaclass()");
ob_type = (PyTypeObject *) type;
Py_INCREF(type);
}
return handle((PyObject *) ob_type);
}
static int init(void *self, PyObject *, PyObject *) {
std::string msg = std::string(Py_TYPE(self)->tp_name) + ": No constructor defined!";
PyErr_SetString(PyExc_TypeError, msg.c_str());
return -1;
}
static PyObject *new_instance(PyTypeObject *type, PyObject *, PyObject *) {
const detail::type_info *type_info = capsule(
PyObject_GetAttrString((PyObject *) type, const_cast<char*>("__pybind__")), false);
instance<void> *self = (instance<void> *) PyType_GenericAlloc(type, 0);
self->value = ::operator new(type_info->type_size);
self->owned = true;
self->parent = nullptr;
self->constructed = false;
detail::get_internals().registered_instances[self->value] = (PyObject *) self;
return (PyObject *) self;
}
static void dealloc(instance<void> *self) {
if (self->value) {
bool dont_cache = self->parent && ((instance<void> *) self->parent)->value == self->value;
if (!dont_cache) { // avoid an issue with internal references matching their parent's address
auto &registered_instances = detail::get_internals().registered_instances;
auto it = registered_instances.find(self->value);
if (it == registered_instances.end())
throw std::runtime_error("Deallocating unregistered instance!");
registered_instances.erase(it);
}
Py_XDECREF(self->parent);
}
Py_TYPE(self)->tp_free((PyObject*) self);
}
void install_buffer_funcs(const std::function<buffer_info *(PyObject *)> &func) {
PyHeapTypeObject *type = (PyHeapTypeObject*) m_ptr;
type->ht_type.tp_as_buffer = &type->as_buffer;
type->as_buffer.bf_getbuffer = getbuffer;
type->as_buffer.bf_releasebuffer = releasebuffer;
((detail::type_info *) capsule(attr("__pybind__")))->get_buffer = func;
}
static int getbuffer(PyObject *obj, Py_buffer *view, int flags) {
auto const &info_func = ((detail::type_info *) capsule(handle(obj).attr("__pybind__")))->get_buffer;
if (view == nullptr || obj == nullptr || !info_func) {
PyErr_SetString(PyExc_BufferError, "Internal error");
return -1;
}
memset(view, 0, sizeof(Py_buffer));
buffer_info *info = info_func(obj);
view->obj = obj;
view->ndim = 1;
view->internal = info;
view->buf = info->ptr;
view->itemsize = info->itemsize;
view->len = view->itemsize;
for (auto s : info->shape)
view->len *= s;
if ((flags & PyBUF_FORMAT) == PyBUF_FORMAT)
view->format = const_cast<char *>(info->format.c_str());
if ((flags & PyBUF_STRIDES) == PyBUF_STRIDES) {
view->ndim = info->ndim;
view->strides = (Py_ssize_t *)&info->strides[0];
view->shape = (Py_ssize_t *) &info->shape[0];
}
Py_INCREF(view->obj);
return 0;
}
static void releasebuffer(PyObject *, Py_buffer *view) { delete (buffer_info *) view->internal; }
};
NAMESPACE_END(detail)
template <typename type, typename holder_type = std::unique_ptr<type>> class class_ : public detail::custom_type {
public:
typedef detail::instance<type, holder_type> instance_type;
PYTHON_OBJECT(class_, detail::custom_type, PyType_Check)
class_(object &scope, const char *name, const char *doc = nullptr)
: detail::custom_type(scope, name, type_id<type>(), sizeof(type),
sizeof(instance_type), init_holder, dealloc,
nullptr, doc) { }
class_(object &scope, const char *name, object &parent,
const char *doc = nullptr)
: detail::custom_type(scope, name, type_id<type>(), sizeof(type),
sizeof(instance_type), init_holder, dealloc,
parent.ptr(), doc) { }
template <typename Func>
class_ &def(const char *name, Func f, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic) {
attr(name) = cpp_method(f, name, doc, policy, (function) attr(name));
return *this;
}
template <typename Func> class_ &
def_static(const char *name, Func f, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic) {
attr(name) = cpp_function(f, name, doc, policy, (function) attr(name));
return *this;
}
template <detail::op_id id, detail::op_type ot, typename L, typename R>
class_ &def(const detail::op_<id, ot, L, R> &op, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic) {
op.template execute<type>(*this, doc, policy);
return *this;
}
template <detail::op_id id, detail::op_type ot, typename L, typename R> class_ &
def_cast(const detail::op_<id, ot, L, R> &op, const char *doc = nullptr,
return_value_policy policy = return_value_policy::automatic) {
op.template execute_cast<type>(*this, doc, policy);
return *this;
}
template <typename... Args>
class_ &def(const detail::init<Args...> &init, const char *doc = nullptr) {
init.template execute<type>(*this, doc);
return *this;
}
class_& def_buffer(const std::function<buffer_info(type&)> &func) {
install_buffer_funcs([func](PyObject *obj) -> buffer_info* {
detail::type_caster<type> caster;
if (!caster.load(obj, false))
return nullptr;
return new buffer_info(func(caster));
});
return *this;
}
template <typename C, typename D>
class_ &def_readwrite(const char *name, D C::*pm,
const char *doc = nullptr) {
cpp_method fget([pm](const C &c) -> const D &{ return c.*pm; }, nullptr,
nullptr, return_value_policy::reference_internal),
fset([pm](C &c, const D &value) { c.*pm = value; });
def_property(name, fget, fset, doc);
return *this;
}
template <typename C, typename D>
class_ &def_readonly(const char *name, const D C::*pm,
const char *doc = nullptr) {
cpp_method fget([pm](const C &c) -> const D &{ return c.*pm; }, nullptr,
nullptr, return_value_policy::reference_internal);
def_property(name, fget, doc);
return *this;
}
template <typename D>
class_ &def_readwrite_static(const char *name, D *pm,
const char *doc = nullptr) {
cpp_function fget([pm](object) -> const D &{ return *pm; }, nullptr,
nullptr, return_value_policy::reference_internal),
fset([pm](object, const D &value) { *pm = value; });
def_property_static(name, fget, fset, doc);
return *this;
}
template <typename D>
class_ &def_readonly_static(const char *name, const D *pm,
const char *doc = nullptr) {
cpp_function fget([pm](object) -> const D &{ return *pm; }, nullptr,
nullptr, return_value_policy::reference_internal);
def_property_static(name, fget, doc);
return *this;
}
class_ &def_property(const char *name, const cpp_method &fget,
const char *doc = nullptr) {
def_property(name, fget, cpp_method(), doc);
return *this;
}
class_ &def_property_static(const char *name, const cpp_function &fget,
const char *doc = nullptr) {
def_property_static(name, fget, cpp_function(), doc);
return *this;
}
class_ &def_property(const char *name, const cpp_method &fget,
const cpp_method &fset, const char *doc = nullptr) {
object property(
PyObject_CallFunction((PyObject *)&PyProperty_Type,
const_cast<char *>("OOOs"), fget.ptr() ? fget.ptr() : Py_None,
fset.ptr() ? fset.ptr() : Py_None, Py_None, doc), false);
attr(name) = property;
return *this;
}
class_ &def_property_static(const char *name, const cpp_function &fget,
const cpp_function &fset,
const char *doc = nullptr) {
object property(
PyObject_CallFunction((PyObject *)&PyProperty_Type,
const_cast<char *>("OOOs"), fget.ptr() ? fget.ptr() : Py_None,
fset.ptr() ? fset.ptr() : Py_None, Py_None, doc), false);
metaclass().attr(name) = property;
return *this;
}
private:
static void init_holder(PyObject *inst_) {
instance_type *inst = (instance_type *) inst_;
new (&inst->holder) holder_type(inst->value);
inst->constructed = true;
}
static void dealloc(PyObject *inst_) {
instance_type *inst = (instance_type *) inst_;
if (inst->owned) {
if (inst->constructed)
inst->holder.~holder_type();
else
::operator delete(inst->value);
}
custom_type::dealloc((detail::instance<void> *) inst);
}
};
/// Binds C++ enumerations and enumeration classes to Python
template <typename Type> class enum_ : public class_<Type> {
public:
enum_(object &scope, const char *name, const char *doc = nullptr)
: class_<Type>(scope, name, doc), m_parent(scope) {
auto entries = new std::unordered_map<int, const char *>();
this->def("__str__", [name, entries](Type value) -> std::string {
auto it = entries->find(value);
return std::string(name) + "." +
((it == entries->end()) ? std::string("???")
: std::string(it->second));
});
m_entries = entries;
}
/// Export enumeration entries into the parent scope
void export_values() {
PyObject *dict = ((PyTypeObject *) this->m_ptr)->tp_dict;
PyObject *key, *value;
Py_ssize_t pos = 0;
while (PyDict_Next(dict, &pos, &key, &value))
if (PyObject_IsInstance(value, this->m_ptr))
m_parent.attr(key) = value;
}
/// Add an enumeration entry
enum_& value(char const* name, Type value) {
this->attr(name) = pybind::cast(value, return_value_policy::copy);
(*m_entries)[(int) value] = name;
return *this;
}
private:
std::unordered_map<int, const char *> *m_entries;
object &m_parent;
};
NAMESPACE_BEGIN(detail)
template <typename ... Args> struct init {
template <typename Base, typename Holder> void execute(pybind::class_<Base, Holder> &class_, const char *doc) const {
/// Function which calls a specific C++ in-place constructor
class_.def("__init__", [](Base *instance, Args... args) { new (instance) Base(args...); }, doc);
}
};
NAMESPACE_END(detail)
template <typename... Args> detail::init<Args...> init() { return detail::init<Args...>(); };
template <typename InputType, typename OutputType> void implicitly_convertible() {
auto implicit_caster = [](PyObject *obj, PyTypeObject *type) -> PyObject *{
if (!detail::type_caster<InputType>().load(obj, false))
return nullptr;
tuple args(1);
args[0] = obj;
PyObject *result = PyObject_Call((PyObject *) type, args.ptr(), nullptr);
if (result == nullptr)
PyErr_Clear();
return result;
};
std::string output_type_name = type_id<OutputType>();
auto & registered_types = detail::get_internals().registered_types;
auto it = registered_types.find(output_type_name);
if (it == registered_types.end())
throw std::runtime_error("implicitly_convertible: Unable to find type " + output_type_name);
it->second.implicit_conversions.push_back(implicit_caster);
}
inline void init_threading() { PyEval_InitThreads(); }
class gil_scoped_acquire {
PyGILState_STATE state;
public:
inline gil_scoped_acquire() { state = PyGILState_Ensure(); }
inline ~gil_scoped_acquire() { PyGILState_Release(state); }
};
class gil_scoped_release {
PyThreadState *state;
public:
inline gil_scoped_release() { state = PyEval_SaveThread(); }
inline ~gil_scoped_release() { PyEval_RestoreThread(state); }
};
NAMESPACE_END(pybind)
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
#undef PYTHON_OBJECT
#undef PYTHON_OBJECT_DEFAULT
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