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pybind11.h
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pybind11.h
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/*
pybind11/pybind11.h: Main header file of the C++11 python
binding generator library
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
#if defined(__INTEL_COMPILER)
# pragma warning push
# pragma warning disable 68 // integer conversion resulted in a change of sign
# pragma warning disable 186 // pointless comparison of unsigned integer with zero
# pragma warning disable 878 // incompatible exception specifications
# pragma warning disable 1334 // the "template" keyword used for syntactic disambiguation may only be used within a template
# pragma warning disable 1682 // implicit conversion of a 64-bit integral type to a smaller integral type (potential portability problem)
# pragma warning disable 1786 // function "strdup" was declared deprecated
# pragma warning disable 1875 // offsetof applied to non-POD (Plain Old Data) types is nonstandard
# pragma warning disable 2196 // warning #2196: routine is both "inline" and "noinline"
#elif defined(_MSC_VER)
# pragma warning(push)
# pragma warning(disable: 4100) // warning C4100: Unreferenced formal parameter
# pragma warning(disable: 4127) // warning C4127: Conditional expression is constant
# pragma warning(disable: 4512) // warning C4512: Assignment operator was implicitly defined as deleted
# 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: 4702) // warning C4702: unreachable code
# pragma warning(disable: 4522) // warning C4522: multiple assignment operators specified
# pragma warning(disable: 4505) // warning C4505: 'PySlice_GetIndicesEx': unreferenced local function has been removed (PyPy only)
#elif defined(__GNUG__) && !defined(__clang__)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wunused-but-set-parameter"
# pragma GCC diagnostic ignored "-Wunused-but-set-variable"
# pragma GCC diagnostic ignored "-Wmissing-field-initializers"
# pragma GCC diagnostic ignored "-Wstrict-aliasing"
# pragma GCC diagnostic ignored "-Wattributes"
# if __GNUC__ >= 7
# pragma GCC diagnostic ignored "-Wnoexcept-type"
# endif
#endif
#include "attr.h"
#include "gil.h"
#include "options.h"
#include "detail/class.h"
#include "detail/init.h"
#include <memory>
#include <vector>
#include <string>
#include <utility>
#if defined(__GNUG__) && !defined(__clang__)
# include <cxxabi.h>
#endif
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
/// Wraps an arbitrary C++ function/method/lambda function/.. into a callable Python object
class cpp_function : public function {
public:
cpp_function() = default;
cpp_function(std::nullptr_t) { }
/// Construct a cpp_function from a vanilla function pointer
template <typename Return, typename... Args, typename... Extra>
cpp_function(Return (*f)(Args...), const Extra&... extra) {
initialize(f, f, extra...);
}
/// Construct a cpp_function from a lambda function (possibly with internal state)
template <typename Func, typename... Extra,
typename = detail::enable_if_t<detail::is_lambda<Func>::value>>
cpp_function(Func &&f, const Extra&... extra) {
initialize(std::forward<Func>(f),
(detail::function_signature_t<Func> *) nullptr, extra...);
}
/// Construct a cpp_function from a class method (non-const, no ref-qualifier)
template <typename Return, typename Class, typename... Arg, typename... Extra>
cpp_function(Return (Class::*f)(Arg...), const Extra&... extra) {
initialize([f](Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
(Return (*) (Class *, Arg...)) nullptr, extra...);
}
/// Construct a cpp_function from a class method (non-const, lvalue ref-qualifier)
/// A copy of the overload for non-const functions without explicit ref-qualifier
/// but with an added `&`.
template <typename Return, typename Class, typename... Arg, typename... Extra>
cpp_function(Return (Class::*f)(Arg...)&, const Extra&... extra) {
initialize([f](Class *c, Arg... args) -> Return { return (c->*f)(args...); },
(Return (*) (Class *, Arg...)) nullptr, extra...);
}
/// Construct a cpp_function from a class method (const, no ref-qualifier)
template <typename Return, typename Class, typename... Arg, typename... Extra>
cpp_function(Return (Class::*f)(Arg...) const, const Extra&... extra) {
initialize([f](const Class *c, Arg... args) -> Return { return (c->*f)(std::forward<Arg>(args)...); },
(Return (*)(const Class *, Arg ...)) nullptr, extra...);
}
/// Construct a cpp_function from a class method (const, lvalue ref-qualifier)
/// A copy of the overload for const functions without explicit ref-qualifier
/// but with an added `&`.
template <typename Return, typename Class, typename... Arg, typename... Extra>
cpp_function(Return (Class::*f)(Arg...) const&, const Extra&... extra) {
initialize([f](const Class *c, Arg... args) -> Return { return (c->*f)(args...); },
(Return (*)(const Class *, Arg ...)) nullptr, extra...);
}
/// Return the function name
object name() const { return attr("__name__"); }
protected:
struct InitializingFunctionRecordDeleter {
// `destruct(function_record, false)`: `initialize_generic` copies strings and
// takes care of cleaning up in case of exceptions. So pass `false` to `free_strings`.
void operator()(detail::function_record * rec) { destruct(rec, false); }
};
using unique_function_record = std::unique_ptr<detail::function_record, InitializingFunctionRecordDeleter>;
/// Space optimization: don't inline this frequently instantiated fragment
PYBIND11_NOINLINE unique_function_record make_function_record() {
return unique_function_record(new detail::function_record());
}
/// Special internal constructor for functors, lambda functions, etc.
template <typename Func, typename Return, typename... Args, typename... Extra>
void initialize(Func &&f, Return (*)(Args...), const Extra&... extra) {
using namespace detail;
struct capture { remove_reference_t<Func> f; };
/* Store the function including any extra state it might have (e.g. a lambda capture object) */
// The unique_ptr makes sure nothing is leaked in case of an exception.
auto unique_rec = make_function_record();
auto rec = unique_rec.get();
/* Store the capture object directly in the function record if there is enough space */
if (sizeof(capture) <= sizeof(rec->data)) {
/* Without these pragmas, GCC warns that there might not be
enough space to use the placement new operator. However, the
'if' statement above ensures that this is the case. */
#if defined(__GNUG__) && !defined(__clang__) && __GNUC__ >= 6 && !defined(__INTEL_COMPILER)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wplacement-new"
#endif
new ((capture *) &rec->data) capture { std::forward<Func>(f) };
#if defined(__GNUG__) && !defined(__clang__) && __GNUC__ >= 6 && !defined(__INTEL_COMPILER)
# pragma GCC diagnostic pop
#endif
if (!std::is_trivially_destructible<Func>::value)
rec->free_data = [](function_record *r) { ((capture *) &r->data)->~capture(); };
} else {
rec->data[0] = new capture { std::forward<Func>(f) };
rec->free_data = [](function_record *r) { delete ((capture *) r->data[0]); };
}
/* Type casters for the function arguments and return value */
using cast_in = argument_loader<Args...>;
using cast_out = make_caster<
conditional_t<std::is_void<Return>::value, void_type, Return>
>;
static_assert(expected_num_args<Extra...>(sizeof...(Args), cast_in::has_args, cast_in::has_kwargs),
"The number of argument annotations does not match the number of function arguments");
/* Dispatch code which converts function arguments and performs the actual function call */
rec->impl = [](function_call &call) -> handle {
cast_in args_converter;
/* Try to cast the function arguments into the C++ domain */
if (!args_converter.load_args(call))
return PYBIND11_TRY_NEXT_OVERLOAD;
/* Invoke call policy pre-call hook */
process_attributes<Extra...>::precall(call);
/* Get a pointer to the capture object */
auto data = (sizeof(capture) <= sizeof(call.func.data)
? &call.func.data : call.func.data[0]);
auto *cap = const_cast<capture *>(reinterpret_cast<const capture *>(data));
/* Override policy for rvalues -- usually to enforce rvp::move on an rvalue */
return_value_policy policy = return_value_policy_override<Return>::policy(call.func.policy);
/* Function scope guard -- defaults to the compile-to-nothing `void_type` */
using Guard = extract_guard_t<Extra...>;
/* Perform the function call */
handle result = cast_out::cast(
std::move(args_converter).template call<Return, Guard>(cap->f), policy, call.parent);
/* Invoke call policy post-call hook */
process_attributes<Extra...>::postcall(call, result);
return result;
};
/* Process any user-provided function attributes */
process_attributes<Extra...>::init(extra..., rec);
{
constexpr bool has_kw_only_args = any_of<std::is_same<kw_only, Extra>...>::value,
has_pos_only_args = any_of<std::is_same<pos_only, Extra>...>::value,
has_args = any_of<std::is_same<args, Args>...>::value,
has_arg_annotations = any_of<is_keyword<Extra>...>::value;
static_assert(has_arg_annotations || !has_kw_only_args, "py::kw_only requires the use of argument annotations");
static_assert(has_arg_annotations || !has_pos_only_args, "py::pos_only requires the use of argument annotations (for docstrings and aligning the annotations to the argument)");
static_assert(!(has_args && has_kw_only_args), "py::kw_only cannot be combined with a py::args argument");
}
/* Generate a readable signature describing the function's arguments and return value types */
static constexpr auto signature = _("(") + cast_in::arg_names + _(") -> ") + cast_out::name;
PYBIND11_DESCR_CONSTEXPR auto types = decltype(signature)::types();
/* Register the function with Python from generic (non-templated) code */
// Pass on the ownership over the `unique_rec` to `initialize_generic`. `rec` stays valid.
initialize_generic(std::move(unique_rec), signature.text, types.data(), sizeof...(Args));
if (cast_in::has_args) rec->has_args = true;
if (cast_in::has_kwargs) rec->has_kwargs = true;
/* Stash some additional information used by an important optimization in 'functional.h' */
using FunctionType = Return (*)(Args...);
constexpr bool is_function_ptr =
std::is_convertible<Func, FunctionType>::value &&
sizeof(capture) == sizeof(void *);
if (is_function_ptr) {
rec->is_stateless = true;
rec->data[1] = const_cast<void *>(reinterpret_cast<const void *>(&typeid(FunctionType)));
}
}
// Utility class that keeps track of all duplicated strings, and cleans them up in its destructor,
// unless they are released. Basically a RAII-solution to deal with exceptions along the way.
class strdup_guard {
public:
~strdup_guard() {
for (auto s : strings)
std::free(s);
}
char *operator()(const char *s) {
auto t = strdup(s);
strings.push_back(t);
return t;
}
void release() {
strings.clear();
}
private:
std::vector<char *> strings;
};
/// Register a function call with Python (generic non-templated code goes here)
void initialize_generic(unique_function_record &&unique_rec, const char *text,
const std::type_info *const *types, size_t args) {
// Do NOT receive `unique_rec` by value. If this function fails to move out the unique_ptr,
// we do not want this to destuct the pointer. `initialize` (the caller) still relies on the
// pointee being alive after this call. Only move out if a `capsule` is going to keep it alive.
auto rec = unique_rec.get();
// Keep track of strdup'ed strings, and clean them up as long as the function's capsule
// has not taken ownership yet (when `unique_rec.release()` is called).
// Note: This cannot easily be fixed by a `unique_ptr` with custom deleter, because the strings
// are only referenced before strdup'ing. So only *after* the following block could `destruct`
// safely be called, but even then, `repr` could still throw in the middle of copying all strings.
strdup_guard guarded_strdup;
/* Create copies of all referenced C-style strings */
rec->name = guarded_strdup(rec->name ? rec->name : "");
if (rec->doc) rec->doc = guarded_strdup(rec->doc);
for (auto &a: rec->args) {
if (a.name)
a.name = guarded_strdup(a.name);
if (a.descr)
a.descr = guarded_strdup(a.descr);
else if (a.value)
a.descr = guarded_strdup(repr(a.value).cast<std::string>().c_str());
}
rec->is_constructor = !strcmp(rec->name, "__init__") || !strcmp(rec->name, "__setstate__");
#if !defined(NDEBUG) && !defined(PYBIND11_DISABLE_NEW_STYLE_INIT_WARNING)
if (rec->is_constructor && !rec->is_new_style_constructor) {
const auto class_name = detail::get_fully_qualified_tp_name((PyTypeObject *) rec->scope.ptr());
const auto func_name = std::string(rec->name);
PyErr_WarnEx(
PyExc_FutureWarning,
("pybind11-bound class '" + class_name + "' is using an old-style "
"placement-new '" + func_name + "' which has been deprecated. See "
"the upgrade guide in pybind11's docs. This message is only visible "
"when compiled in debug mode.").c_str(), 0
);
}
#endif
/* Generate a proper function signature */
std::string signature;
size_t type_index = 0, arg_index = 0;
for (auto *pc = text; *pc != '\0'; ++pc) {
const auto c = *pc;
if (c == '{') {
// Write arg name for everything except *args and **kwargs.
if (*(pc + 1) == '*')
continue;
// Separator for keyword-only arguments, placed before the kw
// arguments start
if (rec->nargs_kw_only > 0 && arg_index + rec->nargs_kw_only == args)
signature += "*, ";
if (arg_index < rec->args.size() && rec->args[arg_index].name) {
signature += rec->args[arg_index].name;
} else if (arg_index == 0 && rec->is_method) {
signature += "self";
} else {
signature += "arg" + std::to_string(arg_index - (rec->is_method ? 1 : 0));
}
signature += ": ";
} else if (c == '}') {
// Write default value if available.
if (arg_index < rec->args.size() && rec->args[arg_index].descr) {
signature += " = ";
signature += rec->args[arg_index].descr;
}
// Separator for positional-only arguments (placed after the
// argument, rather than before like *
if (rec->nargs_pos_only > 0 && (arg_index + 1) == rec->nargs_pos_only)
signature += ", /";
arg_index++;
} else if (c == '%') {
const std::type_info *t = types[type_index++];
if (!t)
pybind11_fail("Internal error while parsing type signature (1)");
if (auto tinfo = detail::get_type_info(*t)) {
handle th((PyObject *) tinfo->type);
signature +=
th.attr("__module__").cast<std::string>() + "." +
th.attr("__qualname__").cast<std::string>(); // Python 3.3+, but we backport it to earlier versions
} else if (rec->is_new_style_constructor && arg_index == 0) {
// A new-style `__init__` takes `self` as `value_and_holder`.
// Rewrite it to the proper class type.
signature +=
rec->scope.attr("__module__").cast<std::string>() + "." +
rec->scope.attr("__qualname__").cast<std::string>();
} else {
std::string tname(t->name());
detail::clean_type_id(tname);
signature += tname;
}
} else {
signature += c;
}
}
if (arg_index != args || types[type_index] != nullptr)
pybind11_fail("Internal error while parsing type signature (2)");
#if PY_MAJOR_VERSION < 3
if (strcmp(rec->name, "__next__") == 0) {
std::free(rec->name);
rec->name = guarded_strdup("next");
} else if (strcmp(rec->name, "__bool__") == 0) {
std::free(rec->name);
rec->name = guarded_strdup("__nonzero__");
}
#endif
rec->signature = guarded_strdup(signature.c_str());
rec->args.shrink_to_fit();
rec->nargs = (std::uint16_t) args;
if (rec->sibling && PYBIND11_INSTANCE_METHOD_CHECK(rec->sibling.ptr()))
rec->sibling = PYBIND11_INSTANCE_METHOD_GET_FUNCTION(rec->sibling.ptr());
detail::function_record *chain = nullptr, *chain_start = rec;
if (rec->sibling) {
if (PyCFunction_Check(rec->sibling.ptr())) {
auto rec_capsule = reinterpret_borrow<capsule>(PyCFunction_GET_SELF(rec->sibling.ptr()));
chain = (detail::function_record *) rec_capsule;
/* Never append a method to an overload chain of a parent class;
instead, hide the parent's overloads in this case */
if (!chain->scope.is(rec->scope))
chain = nullptr;
}
// Don't trigger for things like the default __init__, which are wrapper_descriptors that we are intentionally replacing
else if (!rec->sibling.is_none() && rec->name[0] != '_')
pybind11_fail("Cannot overload existing non-function object \"" + std::string(rec->name) +
"\" with a function of the same name");
}
if (!chain) {
/* No existing overload was found, create a new function object */
rec->def = new PyMethodDef();
std::memset(rec->def, 0, sizeof(PyMethodDef));
rec->def->ml_name = rec->name;
rec->def->ml_meth = reinterpret_cast<PyCFunction>(reinterpret_cast<void (*) (void)>(*dispatcher));
rec->def->ml_flags = METH_VARARGS | METH_KEYWORDS;
capsule rec_capsule(unique_rec.release(), [](void *ptr) {
destruct((detail::function_record *) ptr);
});
guarded_strdup.release();
object scope_module;
if (rec->scope) {
if (hasattr(rec->scope, "__module__")) {
scope_module = rec->scope.attr("__module__");
} else if (hasattr(rec->scope, "__name__")) {
scope_module = rec->scope.attr("__name__");
}
}
m_ptr = PyCFunction_NewEx(rec->def, rec_capsule.ptr(), scope_module.ptr());
if (!m_ptr)
pybind11_fail("cpp_function::cpp_function(): Could not allocate function object");
} else {
/* Append at the beginning or end of the overload chain */
m_ptr = rec->sibling.ptr();
inc_ref();
if (chain->is_method != rec->is_method)
pybind11_fail("overloading a method with both static and instance methods is not supported; "
#if defined(NDEBUG)
"compile in debug mode for more details"
#else
"error while attempting to bind " + std::string(rec->is_method ? "instance" : "static") + " method " +
std::string(pybind11::str(rec->scope.attr("__name__"))) + "." + std::string(rec->name) + signature
#endif
);
if (rec->prepend) {
// Beginning of chain; we need to replace the capsule's current head-of-the-chain
// pointer with this one, then make this one point to the previous head of the
// chain.
chain_start = rec;
rec->next = chain;
auto rec_capsule = reinterpret_borrow<capsule>(((PyCFunctionObject *) m_ptr)->m_self);
rec_capsule.set_pointer(unique_rec.release());
guarded_strdup.release();
} else {
// Or end of chain (normal behavior)
chain_start = chain;
while (chain->next)
chain = chain->next;
chain->next = unique_rec.release();
guarded_strdup.release();
}
}
std::string signatures;
int index = 0;
/* Create a nice pydoc rec including all signatures and
docstrings of the functions in the overload chain */
if (chain && options::show_function_signatures()) {
// First a generic signature
signatures += rec->name;
signatures += "(*args, **kwargs)\n";
signatures += "Overloaded function.\n\n";
}
// Then specific overload signatures
bool first_user_def = true;
for (auto it = chain_start; it != nullptr; it = it->next) {
if (options::show_function_signatures()) {
if (index > 0) signatures += "\n";
if (chain)
signatures += std::to_string(++index) + ". ";
signatures += rec->name;
signatures += it->signature;
signatures += "\n";
}
if (it->doc && strlen(it->doc) > 0 && options::show_user_defined_docstrings()) {
// If we're appending another docstring, and aren't printing function signatures, we
// need to append a newline first:
if (!options::show_function_signatures()) {
if (first_user_def) first_user_def = false;
else signatures += "\n";
}
if (options::show_function_signatures()) signatures += "\n";
signatures += it->doc;
if (options::show_function_signatures()) signatures += "\n";
}
}
/* Install docstring */
auto *func = (PyCFunctionObject *) m_ptr;
std::free(const_cast<char *>(func->m_ml->ml_doc));
// Install docstring if it's non-empty (when at least one option is enabled)
func->m_ml->ml_doc = signatures.empty() ? nullptr : strdup(signatures.c_str());
if (rec->is_method) {
m_ptr = PYBIND11_INSTANCE_METHOD_NEW(m_ptr, rec->scope.ptr());
if (!m_ptr)
pybind11_fail("cpp_function::cpp_function(): Could not allocate instance method object");
Py_DECREF(func);
}
}
/// When a cpp_function is GCed, release any memory allocated by pybind11
static void destruct(detail::function_record *rec, bool free_strings = true) {
// If on Python 3.9, check the interpreter "MICRO" (patch) version.
// If this is running on 3.9.0, we have to work around a bug.
#if !defined(PYPY_VERSION) && PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION == 9
static bool is_zero = Py_GetVersion()[4] == '0';
#endif
while (rec) {
detail::function_record *next = rec->next;
if (rec->free_data)
rec->free_data(rec);
// During initialization, these strings might not have been copied yet,
// so they cannot be freed. Once the function has been created, they can.
// Check `make_function_record` for more details.
if (free_strings) {
std::free((char *) rec->name);
std::free((char *) rec->doc);
std::free((char *) rec->signature);
for (auto &arg: rec->args) {
std::free(const_cast<char *>(arg.name));
std::free(const_cast<char *>(arg.descr));
}
}
for (auto &arg: rec->args)
arg.value.dec_ref();
if (rec->def) {
std::free(const_cast<char *>(rec->def->ml_doc));
// Python 3.9.0 decref's these in the wrong order; rec->def
// If loaded on 3.9.0, let these leak (use Python 3.9.1 at runtime to fix)
// See https://github.com/python/cpython/pull/22670
#if !defined(PYPY_VERSION) && PY_MAJOR_VERSION == 3 && PY_MINOR_VERSION == 9
if (!is_zero)
delete rec->def;
#else
delete rec->def;
#endif
}
delete rec;
rec = next;
}
}
/// Main dispatch logic for calls to functions bound using pybind11
static PyObject *dispatcher(PyObject *self, PyObject *args_in, PyObject *kwargs_in) {
using namespace detail;
/* Iterator over the list of potentially admissible overloads */
const function_record *overloads = (function_record *) PyCapsule_GetPointer(self, nullptr),
*it = overloads;
/* Need to know how many arguments + keyword arguments there are to pick the right overload */
const auto n_args_in = (size_t) PyTuple_GET_SIZE(args_in);
handle parent = n_args_in > 0 ? PyTuple_GET_ITEM(args_in, 0) : nullptr,
result = PYBIND11_TRY_NEXT_OVERLOAD;
auto self_value_and_holder = value_and_holder();
if (overloads->is_constructor) {
if (!parent || !PyObject_TypeCheck(parent.ptr(), (PyTypeObject *) overloads->scope.ptr())) {
PyErr_SetString(PyExc_TypeError, "__init__(self, ...) called with invalid or missing `self` argument");
return nullptr;
}
const auto tinfo = get_type_info((PyTypeObject *) overloads->scope.ptr());
const auto pi = reinterpret_cast<instance *>(parent.ptr());
self_value_and_holder = pi->get_value_and_holder(tinfo, true);
// If this value is already registered it must mean __init__ is invoked multiple times;
// we really can't support that in C++, so just ignore the second __init__.
if (self_value_and_holder.instance_registered())
return none().release().ptr();
}
try {
// We do this in two passes: in the first pass, we load arguments with `convert=false`;
// in the second, we allow conversion (except for arguments with an explicit
// py::arg().noconvert()). This lets us prefer calls without conversion, with
// conversion as a fallback.
std::vector<function_call> second_pass;
// However, if there are no overloads, we can just skip the no-convert pass entirely
const bool overloaded = it != nullptr && it->next != nullptr;
for (; it != nullptr; it = it->next) {
/* For each overload:
1. Copy all positional arguments we were given, also checking to make sure that
named positional arguments weren't *also* specified via kwarg.
2. If we weren't given enough, try to make up the omitted ones by checking
whether they were provided by a kwarg matching the `py::arg("name")` name. If
so, use it (and remove it from kwargs; if not, see if the function binding
provided a default that we can use.
3. Ensure that either all keyword arguments were "consumed", or that the function
takes a kwargs argument to accept unconsumed kwargs.
4. Any positional arguments still left get put into a tuple (for args), and any
leftover kwargs get put into a dict.
5. Pack everything into a vector; if we have py::args or py::kwargs, they are an
extra tuple or dict at the end of the positional arguments.
6. Call the function call dispatcher (function_record::impl)
If one of these fail, move on to the next overload and keep trying until we get a
result other than PYBIND11_TRY_NEXT_OVERLOAD.
*/
const function_record &func = *it;
size_t num_args = func.nargs; // Number of positional arguments that we need
if (func.has_args) --num_args; // (but don't count py::args
if (func.has_kwargs) --num_args; // or py::kwargs)
size_t pos_args = num_args - func.nargs_kw_only;
if (!func.has_args && n_args_in > pos_args)
continue; // Too many positional arguments for this overload
if (n_args_in < pos_args && func.args.size() < pos_args)
continue; // Not enough positional arguments given, and not enough defaults to fill in the blanks
function_call call(func, parent);
size_t args_to_copy = (std::min)(pos_args, n_args_in); // Protect std::min with parentheses
size_t args_copied = 0;
// 0. Inject new-style `self` argument
if (func.is_new_style_constructor) {
// The `value` may have been preallocated by an old-style `__init__`
// if it was a preceding candidate for overload resolution.
if (self_value_and_holder)
self_value_and_holder.type->dealloc(self_value_and_holder);
call.init_self = PyTuple_GET_ITEM(args_in, 0);
call.args.emplace_back(reinterpret_cast<PyObject *>(&self_value_and_holder));
call.args_convert.push_back(false);
++args_copied;
}
// 1. Copy any position arguments given.
bool bad_arg = false;
for (; args_copied < args_to_copy; ++args_copied) {
const argument_record *arg_rec = args_copied < func.args.size() ? &func.args[args_copied] : nullptr;
if (kwargs_in && arg_rec && arg_rec->name && PyDict_GetItemString(kwargs_in, arg_rec->name)) {
bad_arg = true;
break;
}
handle arg(PyTuple_GET_ITEM(args_in, args_copied));
if (arg_rec && !arg_rec->none && arg.is_none()) {
bad_arg = true;
break;
}
call.args.push_back(arg);
call.args_convert.push_back(arg_rec ? arg_rec->convert : true);
}
if (bad_arg)
continue; // Maybe it was meant for another overload (issue #688)
// We'll need to copy this if we steal some kwargs for defaults
dict kwargs = reinterpret_borrow<dict>(kwargs_in);
// 1.5. Fill in any missing pos_only args from defaults if they exist
if (args_copied < func.nargs_pos_only) {
for (; args_copied < func.nargs_pos_only; ++args_copied) {
const auto &arg_rec = func.args[args_copied];
handle value;
if (arg_rec.value) {
value = arg_rec.value;
}
if (value) {
call.args.push_back(value);
call.args_convert.push_back(arg_rec.convert);
} else
break;
}
if (args_copied < func.nargs_pos_only)
continue; // Not enough defaults to fill the positional arguments
}
// 2. Check kwargs and, failing that, defaults that may help complete the list
if (args_copied < num_args) {
bool copied_kwargs = false;
for (; args_copied < num_args; ++args_copied) {
const auto &arg_rec = func.args[args_copied];
handle value;
if (kwargs_in && arg_rec.name)
value = PyDict_GetItemString(kwargs.ptr(), arg_rec.name);
if (value) {
// Consume a kwargs value
if (!copied_kwargs) {
kwargs = reinterpret_steal<dict>(PyDict_Copy(kwargs.ptr()));
copied_kwargs = true;
}
PyDict_DelItemString(kwargs.ptr(), arg_rec.name);
} else if (arg_rec.value) {
value = arg_rec.value;
}
if (!arg_rec.none && value.is_none()) {
break;
}
if (value) {
call.args.push_back(value);
call.args_convert.push_back(arg_rec.convert);
}
else
break;
}
if (args_copied < num_args)
continue; // Not enough arguments, defaults, or kwargs to fill the positional arguments
}
// 3. Check everything was consumed (unless we have a kwargs arg)
if (kwargs && !kwargs.empty() && !func.has_kwargs)
continue; // Unconsumed kwargs, but no py::kwargs argument to accept them
// 4a. If we have a py::args argument, create a new tuple with leftovers
if (func.has_args) {
tuple extra_args;
if (args_to_copy == 0) {
// We didn't copy out any position arguments from the args_in tuple, so we
// can reuse it directly without copying:
extra_args = reinterpret_borrow<tuple>(args_in);
} else if (args_copied >= n_args_in) {
extra_args = tuple(0);
} else {
size_t args_size = n_args_in - args_copied;
extra_args = tuple(args_size);
for (size_t i = 0; i < args_size; ++i) {
extra_args[i] = PyTuple_GET_ITEM(args_in, args_copied + i);
}
}
call.args.push_back(extra_args);
call.args_convert.push_back(false);
call.args_ref = std::move(extra_args);
}
// 4b. If we have a py::kwargs, pass on any remaining kwargs
if (func.has_kwargs) {
if (!kwargs.ptr())
kwargs = dict(); // If we didn't get one, send an empty one
call.args.push_back(kwargs);
call.args_convert.push_back(false);
call.kwargs_ref = std::move(kwargs);
}
// 5. Put everything in a vector. Not technically step 5, we've been building it
// in `call.args` all along.
#if !defined(NDEBUG)
if (call.args.size() != func.nargs || call.args_convert.size() != func.nargs)
pybind11_fail("Internal error: function call dispatcher inserted wrong number of arguments!");
#endif
std::vector<bool> second_pass_convert;
if (overloaded) {
// We're in the first no-convert pass, so swap out the conversion flags for a
// set of all-false flags. If the call fails, we'll swap the flags back in for
// the conversion-allowed call below.
second_pass_convert.resize(func.nargs, false);
call.args_convert.swap(second_pass_convert);
}
// 6. Call the function.
try {
loader_life_support guard{};
result = func.impl(call);
} catch (reference_cast_error &) {
result = PYBIND11_TRY_NEXT_OVERLOAD;
}
if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD)
break;
if (overloaded) {
// The (overloaded) call failed; if the call has at least one argument that
// permits conversion (i.e. it hasn't been explicitly specified `.noconvert()`)
// then add this call to the list of second pass overloads to try.
for (size_t i = func.is_method ? 1 : 0; i < pos_args; i++) {
if (second_pass_convert[i]) {
// Found one: swap the converting flags back in and store the call for
// the second pass.
call.args_convert.swap(second_pass_convert);
second_pass.push_back(std::move(call));
break;
}
}
}
}
if (overloaded && !second_pass.empty() && result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
// The no-conversion pass finished without success, try again with conversion allowed
for (auto &call : second_pass) {
try {
loader_life_support guard{};
result = call.func.impl(call);
} catch (reference_cast_error &) {
result = PYBIND11_TRY_NEXT_OVERLOAD;
}
if (result.ptr() != PYBIND11_TRY_NEXT_OVERLOAD) {
// The error reporting logic below expects 'it' to be valid, as it would be
// if we'd encountered this failure in the first-pass loop.
if (!result)
it = &call.func;
break;
}
}
}
} catch (error_already_set &e) {
e.restore();
return nullptr;
#ifdef __GLIBCXX__
} catch ( abi::__forced_unwind& ) {
throw;
#endif
} catch (...) {
/* When an exception is caught, give each registered exception
translator a chance to translate it to a Python exception
in reverse order of registration.
A translator may choose to do one of the following:
- catch the exception and call PyErr_SetString or PyErr_SetObject
to set a standard (or custom) Python exception, or
- do nothing and let the exception fall through to the next translator, or
- delegate translation to the next translator by throwing a new type of exception. */
auto last_exception = std::current_exception();
auto ®istered_exception_translators = get_internals().registered_exception_translators;
for (auto& translator : registered_exception_translators) {
try {
translator(last_exception);
} catch (...) {
last_exception = std::current_exception();
continue;
}
return nullptr;
}
PyErr_SetString(PyExc_SystemError, "Exception escaped from default exception translator!");
return nullptr;
}
auto append_note_if_missing_header_is_suspected = [](std::string &msg) {
if (msg.find("std::") != std::string::npos) {
msg += "\n\n"
"Did you forget to `#include <pybind11/stl.h>`? Or <pybind11/complex.h>,\n"
"<pybind11/functional.h>, <pybind11/chrono.h>, etc. Some automatic\n"
"conversions are optional and require extra headers to be included\n"
"when compiling your pybind11 module.";
}
};
if (result.ptr() == PYBIND11_TRY_NEXT_OVERLOAD) {
if (overloads->is_operator)
return handle(Py_NotImplemented).inc_ref().ptr();
std::string msg = std::string(overloads->name) + "(): incompatible " +
std::string(overloads->is_constructor ? "constructor" : "function") +
" arguments. The following argument types are supported:\n";
int ctr = 0;
for (const function_record *it2 = overloads; it2 != nullptr; it2 = it2->next) {
msg += " "+ std::to_string(++ctr) + ". ";
bool wrote_sig = false;
if (overloads->is_constructor) {
// For a constructor, rewrite `(self: Object, arg0, ...) -> NoneType` as `Object(arg0, ...)`
std::string sig = it2->signature;
size_t start = sig.find('(') + 7; // skip "(self: "
if (start < sig.size()) {
// End at the , for the next argument
size_t end = sig.find(", "), next = end + 2;
size_t ret = sig.rfind(" -> ");
// Or the ), if there is no comma:
if (end >= sig.size()) next = end = sig.find(')');
if (start < end && next < sig.size()) {
msg.append(sig, start, end - start);
msg += '(';
msg.append(sig, next, ret - next);
wrote_sig = true;
}
}
}
if (!wrote_sig) msg += it2->signature;
msg += "\n";
}
msg += "\nInvoked with: ";
auto args_ = reinterpret_borrow<tuple>(args_in);
bool some_args = false;
for (size_t ti = overloads->is_constructor ? 1 : 0; ti < args_.size(); ++ti) {
if (!some_args) some_args = true;
else msg += ", ";
try {
msg += pybind11::repr(args_[ti]);
} catch (const error_already_set&) {
msg += "<repr raised Error>";
}
}
if (kwargs_in) {
auto kwargs = reinterpret_borrow<dict>(kwargs_in);
if (!kwargs.empty()) {
if (some_args) msg += "; ";
msg += "kwargs: ";
bool first = true;
for (auto kwarg : kwargs) {
if (first) first = false;
else msg += ", ";
msg += pybind11::str("{}=").format(kwarg.first);
try {
msg += pybind11::repr(kwarg.second);
} catch (const error_already_set&) {
msg += "<repr raised Error>";
}
}
}
}
append_note_if_missing_header_is_suspected(msg);
PyErr_SetString(PyExc_TypeError, msg.c_str());
return nullptr;
} else if (!result) {
std::string msg = "Unable to convert function return value to a "
"Python type! The signature was\n\t";
msg += it->signature;
append_note_if_missing_header_is_suspected(msg);
PyErr_SetString(PyExc_TypeError, msg.c_str());
return nullptr;
} else {
if (overloads->is_constructor && !self_value_and_holder.holder_constructed()) {
auto *pi = reinterpret_cast<instance *>(parent.ptr());
self_value_and_holder.type->init_instance(pi, nullptr);
}
return result.ptr();
}
}
};
/// Wrapper for Python extension modules
class module_ : public object {
public:
PYBIND11_OBJECT_DEFAULT(module_, object, PyModule_Check)
/// Create a new top-level Python module with the given name and docstring
PYBIND11_DEPRECATED("Use PYBIND11_MODULE or module_::create_extension_module instead")
explicit module_(const char *name, const char *doc = nullptr) {
#if PY_MAJOR_VERSION >= 3
*this = create_extension_module(name, doc, new PyModuleDef());
#else
*this = create_extension_module(name, doc, nullptr);
#endif
}
/** \rst
Create Python binding for a new function within the module scope. ``Func``
can be a plain C++ function, a function pointer, or a lambda function. For
details on the ``Extra&& ... extra`` argument, see section :ref:`extras`.
\endrst */
template <typename Func, typename... Extra>
module_ &def(const char *name_, Func &&f, const Extra& ... extra) {
cpp_function func(std::forward<Func>(f), name(name_), scope(*this),
sibling(getattr(*this, name_, none())), extra...);
// NB: allow overwriting here because cpp_function sets up a chain with the intention of
// overwriting (and has already checked internally that it isn't overwriting non-functions).
add_object(name_, func, true /* overwrite */);
return *this;
}
/** \rst
Create and return a new Python submodule with the given name and docstring.
This also works recursively, i.e.
.. code-block:: cpp
py::module_ m("example", "pybind11 example plugin");
py::module_ m2 = m.def_submodule("sub", "A submodule of 'example'");
py::module_ m3 = m2.def_submodule("subsub", "A submodule of 'example.sub'");
\endrst */
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);
auto result = reinterpret_borrow<module_>(PyImport_AddModule(full_name.c_str()));
if (doc && options::show_user_defined_docstrings())
result.attr("__doc__") = pybind11::str(doc);
attr(name) = result;
return result;
}
/// Import and return a module or throws `error_already_set`.
static module_ import(const char *name) {
PyObject *obj = PyImport_ImportModule(name);
if (!obj)
throw error_already_set();
return reinterpret_steal<module_>(obj);
}
/// Reload the module or throws `error_already_set`.
void reload() {