/*
pybind11/detail/type_caster_base.h (originally first part of pybind11/cast.h)
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 "common.h"
#include "descr.h"
#include "internals.h"
#include "typeid.h"
#include <cstdint>
#include <iterator>
#include <new>
#include <string>
#include <type_traits>
#include <typeindex>
#include <typeinfo>
#include <unordered_map>
#include <utility>
#include <vector>
PYBIND11_NAMESPACE_BEGIN(PYBIND11_NAMESPACE)
PYBIND11_NAMESPACE_BEGIN(detail)
/// A life support system for temporary objects created by `type_caster::load()`.
/// Adding a patient will keep it alive up until the enclosing function returns.
class loader_life_support {
private:
loader_life_support *parent = nullptr;
std::unordered_set<PyObject *> keep_alive;
#if defined(WITH_THREAD)
// Store stack pointer in thread-local storage.
static PYBIND11_TLS_KEY_REF get_stack_tls_key() {
# if PYBIND11_INTERNALS_VERSION == 4
return get_local_internals().loader_life_support_tls_key;
# else
return get_internals().loader_life_support_tls_key;
# endif
}
static loader_life_support *get_stack_top() {
return static_cast<loader_life_support *>(PYBIND11_TLS_GET_VALUE(get_stack_tls_key()));
}
static void set_stack_top(loader_life_support *value) {
PYBIND11_TLS_REPLACE_VALUE(get_stack_tls_key(), value);
}
#else
// Use single global variable for stack.
static loader_life_support **get_stack_pp() {
static loader_life_support *global_stack = nullptr;
return global_stack;
}
static loader_life_support *get_stack_top() { return *get_stack_pp(); }
static void set_stack_top(loader_life_support *value) { *get_stack_pp() = value; }
#endif
public:
/// A new patient frame is created when a function is entered
loader_life_support() : parent{get_stack_top()} { set_stack_top(this); }
/// ... and destroyed after it returns
~loader_life_support() {
if (get_stack_top() != this) {
pybind11_fail("loader_life_support: internal error");
}
set_stack_top(parent);
for (auto *item : keep_alive) {
Py_DECREF(item);
}
}
/// This can only be used inside a pybind11-bound function, either by `argument_loader`
/// at argument preparation time or by `py::cast()` at execution time.
PYBIND11_NOINLINE static void add_patient(handle h) {
loader_life_support *frame = get_stack_top();
if (!frame) {
// NOTE: It would be nice to include the stack frames here, as this indicates
// use of pybind11::cast<> outside the normal call framework, finding such
// a location is challenging. Developers could consider printing out
// stack frame addresses here using something like __builtin_frame_address(0)
throw cast_error("When called outside a bound function, py::cast() cannot "
"do Python -> C++ conversions which require the creation "
"of temporary values");
}
if (frame->keep_alive.insert(h.ptr()).second) {
Py_INCREF(h.ptr());
}
}
};
// Gets the cache entry for the given type, creating it if necessary. The return value is the pair
// returned by emplace, i.e. an iterator for the entry and a bool set to `true` if the entry was
// just created.
inline std::pair<decltype(internals::registered_types_py)::iterator, bool>
all_type_info_get_cache(PyTypeObject *type);
// Band-aid workaround to fix a subtle but serious bug in a minimalistic fashion. See PR #4762.
inline void all_type_info_add_base_most_derived_first(std::vector<type_info *> &bases,
type_info *addl_base) {
for (auto it = bases.begin(); it != bases.end(); it++) {
type_info *existing_base = *it;
if (PyType_IsSubtype(addl_base->type, existing_base->type) != 0) {
bases.insert(it, addl_base);
return;
}
}
bases.push_back(addl_base);
}
// Populates a just-created cache entry.
PYBIND11_NOINLINE void all_type_info_populate(PyTypeObject *t, std::vector<type_info *> &bases) {
assert(bases.empty());
std::vector<PyTypeObject *> check;
for (handle parent : reinterpret_borrow<tuple>(t->tp_bases)) {
check.push_back((PyTypeObject *) parent.ptr());
}
auto const &type_dict = get_internals().registered_types_py;
for (size_t i = 0; i < check.size(); i++) {
auto *type = check[i];
// Ignore Python2 old-style class super type:
if (!PyType_Check((PyObject *) type)) {
continue;
}
// Check `type` in the current set of registered python types:
auto it = type_dict.find(type);
if (it != type_dict.end()) {
// We found a cache entry for it, so it's either pybind-registered or has pre-computed
// pybind bases, but we have to make sure we haven't already seen the type(s) before:
// we want to follow Python/virtual C++ rules that there should only be one instance of
// a common base.
for (auto *tinfo : it->second) {
// NB: Could use a second set here, rather than doing a linear search, but since
// having a large number of immediate pybind11-registered types seems fairly
// unlikely, that probably isn't worthwhile.
bool found = false;
for (auto *known : bases) {
if (known == tinfo) {
found = true;
break;
}
}
if (!found) {
all_type_info_add_base_most_derived_first(bases, tinfo);
}
}
} else if (type->tp_bases) {
// It's some python type, so keep follow its bases classes to look for one or more
// registered types
if (i + 1 == check.size()) {
// When we're at the end, we can pop off the current element to avoid growing
// `check` when adding just one base (which is typical--i.e. when there is no
// multiple inheritance)
check.pop_back();
i--;
}
for (handle parent : reinterpret_borrow<tuple>(type->tp_bases)) {
check.push_back((PyTypeObject *) parent.ptr());
}
}
}
}
/**
* Extracts vector of type_info pointers of pybind-registered roots of the given Python type. Will
* be just 1 pybind type for the Python type of a pybind-registered class, or for any Python-side
* derived class that uses single inheritance. Will contain as many types as required for a Python
* class that uses multiple inheritance to inherit (directly or indirectly) from multiple
* pybind-registered classes. Will be empty if neither the type nor any base classes are
* pybind-registered.
*
* The value is cached for the lifetime of the Python type.
*/
inline const std::vector<detail::type_info *> &all_type_info(PyTypeObject *type) {
auto ins = all_type_info_get_cache(type);
if (ins.second) {
// New cache entry: populate it
all_type_info_populate(type, ins.first->second);
}
return ins.first->second;
}
/**
* Gets a single pybind11 type info for a python type. Returns nullptr if neither the type nor any
* ancestors are pybind11-registered. Throws an exception if there are multiple bases--use
* `all_type_info` instead if you want to support multiple bases.
*/
PYBIND11_NOINLINE detail::type_info *get_type_info(PyTypeObject *type) {
const auto &bases = all_type_info(type);
if (bases.empty()) {
return nullptr;
}
if (bases.size() > 1) {
pybind11_fail(
"pybind11::detail::get_type_info: type has multiple pybind11-registered bases");
}
return bases.front();
}
inline detail::type_info *get_local_type_info(const std::type_index &tp) {
auto &locals = get_local_internals().registered_types_cpp;
auto it = locals.find(tp);
if (it != locals.end()) {
return it->second;
}
return nullptr;
}
inline detail::type_info *get_global_type_info(const std::type_index &tp) {
auto &types = get_internals().registered_types_cpp;
auto it = types.find(tp);
if (it != types.end()) {
return it->second;
}
return nullptr;
}
/// Return the type info for a given C++ type; on lookup failure can either throw or return
/// nullptr.
PYBIND11_NOINLINE detail::type_info *get_type_info(const std::type_index &tp,
bool throw_if_missing = false) {
if (auto *ltype = get_local_type_info(tp)) {
return ltype;
}
if (auto *gtype = get_global_type_info(tp)) {
return gtype;
}
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 \""
+ std::move(tname) + '"');
}
return nullptr;
}
PYBIND11_NOINLINE 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);
}
// Searches the inheritance graph for a registered Python instance, using all_type_info().
PYBIND11_NOINLINE handle find_registered_python_instance(void *src,
const detail::type_info *tinfo) {
auto it_instances = get_internals().registered_instances.equal_range(src);
for (auto it_i = it_instances.first; it_i != it_instances.second; ++it_i) {
for (auto *instance_type : detail::all_type_info(Py_TYPE(it_i->second))) {
if (instance_type && same_type(*instance_type->cpptype, *tinfo->cpptype)) {
return handle((PyObject *) it_i->second).inc_ref();
}
}
}
return handle();
}
struct value_and_holder {
instance *inst = nullptr;
size_t index = 0u;
const detail::type_info *type = nullptr;
void **vh = nullptr;
// Main constructor for a found value/holder:
value_and_holder(instance *i, const detail::type_info *type, size_t vpos, size_t index)
: inst{i}, index{index}, type{type},
vh{inst->simple_layout ? inst->simple_value_holder
: &inst->nonsimple.values_and_holders[vpos]} {}
// Default constructor (used to signal a value-and-holder not found by get_value_and_holder())
value_and_holder() = default;
// Used for past-the-end iterator
explicit value_and_holder(size_t index) : index{index} {}
template <typename V = void>
V *&value_ptr() const {
return reinterpret_cast<V *&>(vh[0]);
}
// True if this `value_and_holder` has a non-null value pointer
explicit operator bool() const { return value_ptr() != nullptr; }
template <typename H>
H &holder() const {
return reinterpret_cast<H &>(vh[1]);
}
bool holder_constructed() const {
return inst->simple_layout
? inst->simple_holder_constructed
: (inst->nonsimple.status[index] & instance::status_holder_constructed) != 0u;
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void set_holder_constructed(bool v = true) {
if (inst->simple_layout) {
inst->simple_holder_constructed = v;
} else if (v) {
inst->nonsimple.status[index] |= instance::status_holder_constructed;
} else {
inst->nonsimple.status[index] &= (std::uint8_t) ~instance::status_holder_constructed;
}
}
bool instance_registered() const {
return inst->simple_layout
? inst->simple_instance_registered
: ((inst->nonsimple.status[index] & instance::status_instance_registered) != 0);
}
// NOLINTNEXTLINE(readability-make-member-function-const)
void set_instance_registered(bool v = true) {
if (inst->simple_layout) {
inst->simple_instance_registered = v;
} else if (v) {
inst->nonsimple.status[index] |= instance::status_instance_registered;
} else {
inst->nonsimple.status[index] &= (std::uint8_t) ~instance::status_instance_registered;
}
}
};
// Container for accessing and iterating over an instance's values/holders
struct values_and_holders {
private:
instance *inst;
using type_vec = std::vector<detail::type_info *>;
const type_vec &tinfo;
public:
explicit values_and_holders(instance *inst)
: inst{inst}, tinfo(all_type_info(Py_TYPE(inst))) {}
explicit values_and_holders(PyObject *obj)
: inst{nullptr}, tinfo(all_type_info(Py_TYPE(obj))) {
if (!tinfo.empty()) {
inst = reinterpret_cast<instance *>(obj);
}
}
struct iterator {
private:
instance *inst = nullptr;
const type_vec *types = nullptr;
value_and_holder curr;
friend struct values_and_holders;
iterator(instance *inst, const type_vec *tinfo) : inst{inst}, types{tinfo} {
if (inst != nullptr) {
assert(!types->empty());
curr = value_and_holder(
inst /* instance */,
(*types)[0] /* type info */,
0, /* vpos: (non-simple types only): the first vptr comes first */
0 /* index */);
}
}
// Past-the-end iterator:
explicit iterator(size_t end) : curr(end) {}
public:
bool operator==(const iterator &other) const { return curr.index == other.curr.index; }
bool operator!=(const iterator &other) const { return curr.index != other.curr.index; }
iterator &operator++() {
if (!inst->simple_layout) {
curr.vh += 1 + (*types)[curr.index]->holder_size_in_ptrs;
}
++curr.index;
curr.type = curr.index < types->size() ? (*types)[curr.index] : nullptr;
return *this;
}
value_and_holder &operator*() { return curr; }
value_and_holder *operator->() { return &curr; }
};
iterator begin() { return iterator(inst, &tinfo); }
iterator end() { return iterator(tinfo.size()); }
iterator find(const type_info *find_type) {
auto it = begin(), endit = end();
while (it != endit && it->type != find_type) {
++it;
}
return it;
}
size_t size() { return tinfo.size(); }
// Band-aid workaround to fix a subtle but serious bug in a minimalistic fashion. See PR #4762.
bool is_redundant_value_and_holder(const value_and_holder &vh) {
for (size_t i = 0; i < vh.index; i++) {
if (PyType_IsSubtype(tinfo[i]->type, tinfo[vh.index]->type) != 0) {
return true;
}
}
return false;
}
};
/**
* Extracts C++ value and holder pointer references from an instance (which may contain multiple
* values/holders for python-side multiple inheritance) that match the given type. Throws an error
* if the given type (or ValueType, if omitted) is not a pybind11 base of the given instance. If
* `find_type` is omitted (or explicitly specified as nullptr) the first value/holder are returned,
* regardless of type (and the resulting .type will be nullptr).
*
* The returned object should be short-lived: in particular, it must not outlive the called-upon
* instance.
*/
PYBIND11_NOINLINE value_and_holder
instance::get_value_and_holder(const type_info *find_type /*= nullptr default in common.h*/,
bool throw_if_missing /*= true in common.h*/) {
// Optimize common case:
if (!find_type || Py_TYPE(this) == find_type->type) {
return value_and_holder(this, find_type, 0, 0);
}
detail::values_and_holders vhs(this);
auto it = vhs.find(find_type);
if (it != vhs.end()) {
return *it;
}
if (!throw_if_missing) {
return value_and_holder();
}
#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
pybind11_fail("pybind11::detail::instance::get_value_and_holder: `"
+ get_fully_qualified_tp_name(find_type->type)
+ "' is not a pybind11 base of the given `"
+ get_fully_qualified_tp_name(Py_TYPE(this)) + "' instance");
#else
pybind11_fail(
"pybind11::detail::instance::get_value_and_holder: "
"type is not a pybind11 base of the given instance "
"(#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in debug mode for type details)");
#endif
}
PYBIND11_NOINLINE void instance::allocate_layout() {
const auto &tinfo = all_type_info(Py_TYPE(this));
const size_t n_types = tinfo.size();
if (n_types == 0) {
pybind11_fail(
"instance allocation failed: new instance has no pybind11-registered base types");
}
simple_layout
= n_types == 1 && tinfo.front()->holder_size_in_ptrs <= instance_simple_holder_in_ptrs();
// Simple path: no python-side multiple inheritance, and a small-enough holder
if (simple_layout) {
simple_value_holder[0] = nullptr;
simple_holder_constructed = false;
simple_instance_registered = false;
} else { // multiple base types or a too-large holder
// Allocate space to hold: [v1*][h1][v2*][h2]...[bb...] where [vN*] is a value pointer,
// [hN] is the (uninitialized) holder instance for value N, and [bb...] is a set of bool
// values that tracks whether each associated holder has been initialized. Each [block] is
// padded, if necessary, to an integer multiple of sizeof(void *).
size_t space = 0;
for (auto *t : tinfo) {
space += 1; // value pointer
space += t->holder_size_in_ptrs; // holder instance
}
size_t flags_at = space;
space += size_in_ptrs(n_types); // status bytes (holder_constructed and
// instance_registered)
// Allocate space for flags, values, and holders, and initialize it to 0 (flags and values,
// in particular, need to be 0). Use Python's memory allocation
// functions: Python is using pymalloc, which is designed to be
// efficient for small allocations like the one we're doing here;
// for larger allocations they are just wrappers around malloc.
// TODO: is this still true for pure Python 3.6?
nonsimple.values_and_holders = (void **) PyMem_Calloc(space, sizeof(void *));
if (!nonsimple.values_and_holders) {
throw std::bad_alloc();
}
nonsimple.status
= reinterpret_cast<std::uint8_t *>(&nonsimple.values_and_holders[flags_at]);
}
owned = true;
}
// NOLINTNEXTLINE(readability-make-member-function-const)
PYBIND11_NOINLINE void instance::deallocate_layout() {
if (!simple_layout) {
PyMem_Free(nonsimple.values_and_holders);
}
}
PYBIND11_NOINLINE 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 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) {
for (const auto &vh : values_and_holders(it->second)) {
if (vh.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 < 0x030D0000
return _PyThreadState_UncheckedGet();
#else
return PyThreadState_GetUnchecked();
#endif
}
// Forward declarations
void keep_alive_impl(handle nurse, handle patient);
inline PyObject *make_new_instance(PyTypeObject *type);
class type_caster_generic {
public:
PYBIND11_NOINLINE explicit type_caster_generic(const std::type_info &type_info)
: typeinfo(get_type_info(type_info)), cpptype(&type_info) {}
explicit type_caster_generic(const type_info *typeinfo)
: typeinfo(typeinfo), cpptype(typeinfo ? typeinfo->cpptype : nullptr) {}
bool load(handle src, bool convert) { return load_impl<type_caster_generic>(src, convert); }
PYBIND11_NOINLINE static handle cast(const void *_src,
return_value_policy policy,
handle parent,
const detail::type_info *tinfo,
void *(*copy_constructor)(const void *),
void *(*move_constructor)(const void *),
const void *existing_holder = nullptr) {
if (!tinfo) { // no type info: error will be set already
return handle();
}
void *src = const_cast<void *>(_src);
if (src == nullptr) {
return none().release();
}
if (handle registered_inst = find_registered_python_instance(src, tinfo)) {
return registered_inst;
}
auto inst = reinterpret_steal<object>(make_new_instance(tinfo->type));
auto *wrapper = reinterpret_cast<instance *>(inst.ptr());
wrapper->owned = false;
void *&valueptr = values_and_holders(wrapper).begin()->value_ptr();
switch (policy) {
case return_value_policy::automatic:
case return_value_policy::take_ownership:
valueptr = src;
wrapper->owned = true;
break;
case return_value_policy::automatic_reference:
case return_value_policy::reference:
valueptr = src;
wrapper->owned = false;
break;
case return_value_policy::copy:
if (copy_constructor) {
valueptr = copy_constructor(src);
} else {
#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
std::string type_name(tinfo->cpptype->name());
detail::clean_type_id(type_name);
throw cast_error("return_value_policy = copy, but type " + type_name
+ " is non-copyable!");
#else
throw cast_error("return_value_policy = copy, but type is "
"non-copyable! (#define PYBIND11_DETAILED_ERROR_MESSAGES or "
"compile in debug mode for details)");
#endif
}
wrapper->owned = true;
break;
case return_value_policy::move:
if (move_constructor) {
valueptr = move_constructor(src);
} else if (copy_constructor) {
valueptr = copy_constructor(src);
} else {
#if defined(PYBIND11_DETAILED_ERROR_MESSAGES)
std::string type_name(tinfo->cpptype->name());
detail::clean_type_id(type_name);
throw cast_error("return_value_policy = move, but type " + type_name
+ " is neither movable nor copyable!");
#else
throw cast_error("return_value_policy = move, but type is neither "
"movable nor copyable! "
"(#define PYBIND11_DETAILED_ERROR_MESSAGES or compile in "
"debug mode for details)");
#endif
}
wrapper->owned = true;
break;
case return_value_policy::reference_internal:
valueptr = src;
wrapper->owned = false;
keep_alive_impl(inst, parent);
break;
default:
throw cast_error("unhandled return_value_policy: should not happen!");
}
tinfo->init_instance(wrapper, existing_holder);
return inst.release();
}
// Base methods for generic caster; there are overridden in copyable_holder_caster
void load_value(value_and_holder &&v_h) {
auto *&vptr = v_h.value_ptr();
// Lazy allocation for unallocated values:
if (vptr == nullptr) {
const auto *type = v_h.type ? v_h.type : typeinfo;
if (type->operator_new) {
vptr = type->operator_new(type->type_size);
} else {
#if defined(__cpp_aligned_new) && (!defined(_MSC_VER) || _MSC_VER >= 1912)
if (type->type_align > __STDCPP_DEFAULT_NEW_ALIGNMENT__) {
vptr = ::operator new(type->type_size, std::align_val_t(type->type_align));
} else {
vptr = ::operator new(type->type_size);
}
#else
vptr = ::operator new(type->type_size);
#endif
}
}
value = vptr;
}
bool try_implicit_casts(handle src, bool convert) {
for (const 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;
}
}
return false;
}
bool try_direct_conversions(handle src) {
for (auto &converter : *typeinfo->direct_conversions) {
if (converter(src.ptr(), value)) {
return true;
}
}
return false;
}
void check_holder_compat() {}
PYBIND11_NOINLINE static void *local_load(PyObject *src, const type_info *ti) {
auto caster = type_caster_generic(ti);
if (caster.load(src, false)) {
return caster.value;
}
return nullptr;
}
/// Try to load with foreign typeinfo, if available. Used when there is no
/// native typeinfo, or when the native one wasn't able to produce a value.
PYBIND11_NOINLINE bool try_load_foreign_module_local(handle src) {
constexpr auto *local_key = PYBIND11_MODULE_LOCAL_ID;
const auto pytype = type::handle_of(src);
if (!hasattr(pytype, local_key)) {
return false;
}
type_info *foreign_typeinfo = reinterpret_borrow<capsule>(getattr(pytype, local_key));
// Only consider this foreign loader if actually foreign and is a loader of the correct cpp
// type
if (foreign_typeinfo->module_local_load == &local_load
|| (cpptype && !same_type(*cpptype, *foreign_typeinfo->cpptype))) {
return false;
}
if (auto *result = foreign_typeinfo->module_local_load(src.ptr(), foreign_typeinfo)) {
value = result;
return true;
}
return false;
}
// Implementation of `load`; this takes the type of `this` so that it can dispatch the relevant
// bits of code between here and copyable_holder_caster where the two classes need different
// logic (without having to resort to virtual inheritance).
template <typename ThisT>
PYBIND11_NOINLINE bool load_impl(handle src, bool convert) {
if (!src) {
return false;
}
if (!typeinfo) {
return try_load_foreign_module_local(src);
}
auto &this_ = static_cast<ThisT &>(*this);
this_.check_holder_compat();
PyTypeObject *srctype = Py_TYPE(src.ptr());
// Case 1: If src is an exact type match for the target type then we can reinterpret_cast
// the instance's value pointer to the target type:
if (srctype == typeinfo->type) {
this_.load_value(reinterpret_cast<instance *>(src.ptr())->get_value_and_holder());
return true;
}
// Case 2: We have a derived class
if (PyType_IsSubtype(srctype, typeinfo->type)) {
const auto &bases = all_type_info(srctype);
bool no_cpp_mi = typeinfo->simple_type;
// Case 2a: the python type is a Python-inherited derived class that inherits from just
// one simple (no MI) pybind11 class, or is an exact match, so the C++ instance is of
// the right type and we can use reinterpret_cast.
// (This is essentially the same as case 2b, but because not using multiple inheritance
// is extremely common, we handle it specially to avoid the loop iterator and type
// pointer lookup overhead)
if (bases.size() == 1 && (no_cpp_mi || bases.front()->type == typeinfo->type)) {
this_.load_value(reinterpret_cast<instance *>(src.ptr())->get_value_and_holder());
return true;
}
// Case 2b: the python type inherits from multiple C++ bases. Check the bases to see
// if we can find an exact match (or, for a simple C++ type, an inherited match); if
// so, we can safely reinterpret_cast to the relevant pointer.
if (bases.size() > 1) {
for (auto *base : bases) {
if (no_cpp_mi ? PyType_IsSubtype(base->type, typeinfo->type)
: base->type == typeinfo->type) {
this_.load_value(
reinterpret_cast<instance *>(src.ptr())->get_value_and_holder(base));
return true;
}
}
}
// Case 2c: C++ multiple inheritance is involved and we couldn't find an exact type
// match in the registered bases, above, so try implicit casting (needed for proper C++
// casting when MI is involved).
if (this_.try_implicit_casts(src, convert)) {
return true;
}
}
// Perform an implicit conversion
if (convert) {
for (const auto &converter : typeinfo->implicit_conversions) {
auto temp = reinterpret_steal<object>(converter(src.ptr(), typeinfo->type));
if (load_impl<ThisT>(temp, false)) {
loader_life_support::add_patient(temp);
return true;
}
}
if (this_.try_direct_conversions(src)) {
return true;
}
}
// Failed to match local typeinfo. Try again with global.
if (typeinfo->module_local) {
if (auto *gtype = get_global_type_info(*typeinfo->cpptype)) {
typeinfo = gtype;
return load(src, false);
}
}
// Global typeinfo has precedence over foreign module_local
if (try_load_foreign_module_local(src)) {
return true;
}
// Custom converters didn't take None, now we convert None to nullptr.
if (src.is_none()) {
// Defer accepting None to other overloads (if we aren't in convert mode):
if (!convert) {
return false;
}
value = nullptr;
return true;
}
return false;
}
// Called to do type lookup and wrap the pointer and type in a pair when a dynamic_cast
// isn't needed or can't be used. If the type is unknown, sets the error and returns a pair
// with .second = nullptr. (p.first = nullptr is not an error: it becomes None).
PYBIND11_NOINLINE static std::pair<const void *, const type_info *>
src_and_type(const void *src,
const std::type_info &cast_type,
const std::type_info *rtti_type = nullptr) {
if (auto *tpi = get_type_info(cast_type)) {
return {src, const_cast<const type_info *>(tpi)};
}
// Not found, set error:
std::string tname = rtti_type ? rtti_type->name() : cast_type.name();
detail::clean_type_id(tname);
std::string msg = "Unregistered type : " + tname;
set_error(PyExc_TypeError, msg.c_str());
return {nullptr, nullptr};
}
const type_info *typeinfo = nullptr;
const std::type_info *cpptype = nullptr;
void *value = nullptr;
};
/**
* Determine suitable casting operator for pointer-or-lvalue-casting type casters. The type caster
* needs to provide `operator T*()` and `operator T&()` operators.
*
* If the type supports moving the value away via an `operator T&&() &&` method, it should use
* `movable_cast_op_type` instead.
*/
template <typename T>
using cast_op_type = conditional_t<std::is_pointer<remove_reference_t<T>>::value,
typename std::add_pointer<intrinsic_t<T>>::type,
typename std::add_lvalue_reference<intrinsic_t<T>>::type>;
/**
* Determine suitable casting operator for a type caster with a movable value. Such a type caster
* needs to provide `operator T*()`, `operator T&()`, and `operator T&&() &&`. The latter will be
* called in appropriate contexts where the value can be moved rather than copied.
*
* These operator are automatically provided when using the PYBIND11_TYPE_CASTER macro.
*/
template <typename T>
using movable_cast_op_type
= conditional_t<std::is_pointer<typename std::remove_reference<T>::type>::value,
typename std::add_pointer<intrinsic_t<T>>::type,
conditional_t<std::is_rvalue_reference<T>::value,
typename std::add_rvalue_reference<intrinsic_t<T>>::type,
typename std::add_lvalue_reference<intrinsic_t<T>>::type>>;
// Does the container have a mapped type and is it recursive?
// Implemented by specializations below.
template <typename Container, typename SFINAE = void>
struct container_mapped_type_traits {
static constexpr bool has_mapped_type = false;
static constexpr bool has_recursive_mapped_type = false;
};
template <typename Container>
struct container_mapped_type_traits<
Container,
typename std::enable_if<
std::is_same<typename Container::mapped_type, Container>::value>::type> {
static constexpr bool has_mapped_type = true;
static constexpr bool has_recursive_mapped_type = true;
};
template <typename Container>
struct container_mapped_type_traits<
Container,
typename std::enable_if<
negation<std::is_same<typename Container::mapped_type, Container>>::value>::type> {
static constexpr bool has_mapped_type = true;
static constexpr bool has_recursive_mapped_type = false;
};
// Does the container have a value type and is it recursive?
// Implemented by specializations below.
template <typename Container, typename SFINAE = void>
struct container_value_type_traits : std::false_type {
static constexpr bool has_value_type = false;
static constexpr bool has_recursive_value_type = false;
};
template <typename Container>
struct container_value_type_traits<
Container,
typename std::enable_if<
std::is_same<typename Container::value_type, Container>::value>::type> {
static constexpr bool has_value_type = true;
static constexpr bool has_recursive_value_type = true;
};
template <typename Container>
struct container_value_type_traits<
Container,
typename std::enable_if<
negation<std::is_same<typename Container::value_type, Container>>::value>::type> {
static constexpr bool has_value_type = true;
static constexpr bool has_recursive_value_type = false;
};
/*
* Tag to be used for representing the bottom of recursively defined types.
* Define this tag so we don't have to use void.
*/
struct recursive_bottom {};
/*
* Implementation detail of `recursive_container_traits` below.
* `T` is the `value_type` of the container, which might need to be modified to
* avoid recursive types and const types.
*/
template <typename T, bool is_this_a_map>
struct impl_type_to_check_recursively {
/*
* If the container is recursive, then no further recursion should be done.
*/
using if_recursive = recursive_bottom;
/*
* Otherwise yield `T` unchanged.
*/
using if_not_recursive = T;
};
/*
* For pairs - only as value type of a map -, the first type should remove the `const`.
* Also, if the map is recursive, then the recursive checking should consider
* the first type only.
*/
template <typename A, typename B>
struct impl_type_to_check_recursively<std::pair<A, B>, /* is_this_a_map = */ true> {
using if_recursive = typename std::remove_const<A>::type;
using if_not_recursive = std::pair<typename std::remove_const<A>::type, B>;
};
/*
* Implementation of `recursive_container_traits` below.
*/
template <typename Container, typename SFINAE = void>
struct impl_recursive_container_traits {
using type_to_check_recursively = recursive_bottom;
};
template <typename Container>
struct impl_recursive_container_traits<
Container,
typename std::enable_if<container_value_type_traits<Container>::has_value_type>::type> {
static constexpr bool is_recursive
= container_mapped_type_traits<Container>::has_recursive_mapped_type
|| container_value_type_traits<Container>::has_recursive_value_type;
/*
* This member dictates which type Pybind11 should check recursively in traits
* such as `is_move_constructible`, `is_copy_constructible`, `is_move_assignable`, ...
* Direct access to `value_type` should be avoided:
* 1. `value_type` might recursively contain the type again
* 2. `value_type` of STL map types is `std::pair<A const, B>`, the `const`
* should be removed.
*
*/
using type_to_check_recursively = typename std::conditional<
is_recursive,
typename impl_type_to_check_recursively<
typename Container::value_type,
container_mapped_type_traits<Container>::has_mapped_type>::if_recursive,
typename impl_type_to_check_recursively<
typename Container::value_type,
container_mapped_type_traits<Container>::has_mapped_type>::if_not_recursive>::type;
};
/*
* This trait defines the `type_to_check_recursively` which is needed to properly
* handle recursively defined traits such as `is_move_constructible` without going
* into an infinite recursion.
* Should be used instead of directly accessing the `value_type`.
* It cancels the recursion by returning the `recursive_bottom` tag.
*
* The default definition of `type_to_check_recursively` is as follows:
*
* 1. By default, it is `recursive_bottom`, so that the recursion is canceled.
* 2. If the type is non-recursive and defines a `value_type`, then the `value_type` is used.
* If the `value_type` is a pair and a `mapped_type` is defined,
* then the `const` is removed from the first type.
* 3. If the type is recursive and `value_type` is not a pair, then `recursive_bottom` is returned.
* 4. If the type is recursive and `value_type` is a pair and a `mapped_type` is defined,
* then `const` is removed from the first type and the first type is returned.
*
* This behavior can be extended by the user as seen in test_stl_binders.cpp.
*
* This struct is exactly the same as impl_recursive_container_traits.
* The duplication achieves that user-defined specializations don't compete
* with internal specializations, but take precedence.
*/
template <typename Container, typename SFINAE = void>
struct recursive_container_traits : impl_recursive_container_traits<Container> {};
template <typename T>
struct is_move_constructible
: all_of<std::is_move_constructible<T>,
is_move_constructible<
typename recursive_container_traits<T>::type_to_check_recursively>> {};
template <>
struct is_move_constructible<recursive_bottom> : std::true_type {};
// Likewise for std::pair
// (after C++17 it is mandatory that the move constructor not exist when the two types aren't
// themselves move constructible, but this can not be relied upon when T1 or T2 are themselves
// containers).
template <typename T1, typename T2>
struct is_move_constructible<std::pair<T1, T2>>
: all_of<is_move_constructible<T1>, is_move_constructible<T2>> {};
// 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>
struct is_copy_constructible
: all_of<std::is_copy_constructible<T>,
is_copy_constructible<
typename recursive_container_traits<T>::type_to_check_recursively>> {};
template <>
struct is_copy_constructible<recursive_bottom> : std::true_type {};
// Likewise for std::pair
// (after C++17 it is mandatory that the copy constructor not exist when the two types aren't
// themselves copy constructible, but this can not be relied upon when T1 or T2 are themselves
// containers).
template <typename T1, typename T2>
struct is_copy_constructible<std::pair<T1, T2>>
: all_of<is_copy_constructible<T1>, is_copy_constructible<T2>> {};
// The same problems arise with std::is_copy_assignable, so we use the same workaround.
template <typename T>
struct is_copy_assignable
: all_of<
std::is_copy_assignable<T>,
is_copy_assignable<typename recursive_container_traits<T>::type_to_check_recursively>> {
};
template <>
struct is_copy_assignable<recursive_bottom> : std::true_type {};
template <typename T1, typename T2>
struct is_copy_assignable<std::pair<T1, T2>>
: all_of<is_copy_assignable<T1>, is_copy_assignable<T2>> {};
PYBIND11_NAMESPACE_END(detail)
// polymorphic_type_hook<itype>::get(src, tinfo) determines whether the object pointed
// to by `src` actually is an instance of some class derived from `itype`.
// If so, it sets `tinfo` to point to the std::type_info representing that derived
// type, and returns a pointer to the start of the most-derived object of that type
// (in which `src` is a subobject; this will be the same address as `src` in most
// single inheritance cases). If not, or if `src` is nullptr, it simply returns `src`
// and leaves `tinfo` at its default value of nullptr.
//
// The default polymorphic_type_hook just returns src. A specialization for polymorphic
// types determines the runtime type of the passed object and adjusts the this-pointer
// appropriately via dynamic_cast<void*>. This is what enables a C++ Animal* to appear
// to Python as a Dog (if Dog inherits from Animal, Animal is polymorphic, Dog is
// registered with pybind11, and this Animal is in fact a Dog).
//
// You may specialize polymorphic_type_hook yourself for types that want to appear
// polymorphic to Python but do not use C++ RTTI. (This is a not uncommon pattern
// in performance-sensitive applications, used most notably in LLVM.)
//
// polymorphic_type_hook_base allows users to specialize polymorphic_type_hook with
// std::enable_if. User provided specializations will always have higher priority than
// the default implementation and specialization provided in polymorphic_type_hook_base.
template <typename itype, typename SFINAE = void>
struct polymorphic_type_hook_base {
static const void *get(const itype *src, const std::type_info *&) { return src; }
};
template <typename itype>
struct polymorphic_type_hook_base<itype, detail::enable_if_t<std::is_polymorphic<itype>::value>> {
static const void *get(const itype *src, const std::type_info *&type) {
type = src ? &typeid(*src) : nullptr;
return dynamic_cast<const void *>(src);
}
};
template <typename itype, typename SFINAE = void>
struct polymorphic_type_hook : public polymorphic_type_hook_base<itype> {};
PYBIND11_NAMESPACE_BEGIN(detail)
/// 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 constexpr auto name = const_name<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);
}
// Returns a (pointer, type_info) pair taking care of necessary type lookup for a
// polymorphic type (using RTTI by default, but can be overridden by specializing
// polymorphic_type_hook). If the instance isn't derived, returns the base version.
static std::pair<const void *, const type_info *> src_and_type(const itype *src) {
const auto &cast_type = typeid(itype);
const std::type_info *instance_type = nullptr;
const void *vsrc = polymorphic_type_hook<itype>::get(src, instance_type);
if (instance_type && !same_type(cast_type, *instance_type)) {
// This is a base pointer to a derived type. If the derived type is registered
// with pybind11, we want to make the full derived object available.
// In the typical case where itype is polymorphic, we get the correct
// derived pointer (which may be != base pointer) by a dynamic_cast to
// most derived type. If itype is not polymorphic, we won't get here
// except via a user-provided specialization of polymorphic_type_hook,
// and the user has promised that no this-pointer adjustment is
// required in that case, so it's OK to use static_cast.
if (const auto *tpi = get_type_info(*instance_type)) {
return {vsrc, tpi};
}
}
// Otherwise we have either a nullptr, an `itype` pointer, or an unknown derived pointer,
// so don't do a cast
return type_caster_generic::src_and_type(src, cast_type, instance_type);
}
static handle cast(const itype *src, return_value_policy policy, handle parent) {
auto st = src_and_type(src);
return type_caster_generic::cast(st.first,
policy,
parent,
st.second,
make_copy_constructor(src),
make_move_constructor(src));
}
static handle cast_holder(const itype *src, const void *holder) {
auto st = src_and_type(src);
return type_caster_generic::cast(st.first,
return_value_policy::take_ownership,
{},
st.second,
nullptr,
nullptr,
holder);
}
template <typename T>
using cast_op_type = detail::cast_op_type<T>;
// NOLINTNEXTLINE(google-explicit-constructor)
operator itype *() { return (type *) value; }
// NOLINTNEXTLINE(google-explicit-constructor)
operator itype &() {
if (!value) {
throw reference_cast_error();
}
return *((itype *) value);
}
protected:
using Constructor = void *(*) (const void *);
/* Only enabled when the types are {copy,move}-constructible *and* when the type
does not have a private operator new implementation. A comma operator is used in the
decltype argument to apply SFINAE to the public copy/move constructors.*/
template <typename T, typename = enable_if_t<is_copy_constructible<T>::value>>
static auto make_copy_constructor(const T *)
-> decltype(new T(std::declval<const T>()), Constructor{}) {
return [](const void *arg) -> void * { return new T(*reinterpret_cast<const T *>(arg)); };
}
template <typename T, typename = enable_if_t<is_move_constructible<T>::value>>
static auto make_move_constructor(const T *)
-> decltype(new T(std::declval<T &&>()), Constructor{}) {
return [](const void *arg) -> void * {
return new T(std::move(*const_cast<T *>(reinterpret_cast<const T *>(arg))));
};
}
static Constructor make_copy_constructor(...) { return nullptr; }
static Constructor make_move_constructor(...) { return nullptr; }
};
inline std::string quote_cpp_type_name(const std::string &cpp_type_name) {
return cpp_type_name; // No-op for now. See PR #4888
}
PYBIND11_NOINLINE std::string type_info_description(const std::type_info &ti) {
if (auto *type_data = get_type_info(ti)) {
handle th((PyObject *) type_data->type);
return th.attr("__module__").cast<std::string>() + '.'
+ th.attr("__qualname__").cast<std::string>();
}
return quote_cpp_type_name(clean_type_id(ti.name()));
}
PYBIND11_NAMESPACE_END(detail)
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)