folly::exception_wrapper::ExceptionPtr Struct Reference

Public Member Functions
bool	has_exception_ () const
std::exception const *	as_exception_ () const
std::type_info const *	as_type_ () const

Static Public Member Functions
static std::uintptr_t	as_int_ (std::exception_ptr const &ptr, std::exception const &e) noexcept
static std::uintptr_t	as_int_ (std::exception_ptr const &ptr, AnyException e) noexcept
static void	copy_ (exception_wrapper const *from, exception_wrapper *to)
static void	move_ (exception_wrapper *from, exception_wrapper *to)
static void	delete_ (exception_wrapper *that)
static void	throw_ (exception_wrapper const *that)
static std::type_info const *	type_ (exception_wrapper const *that)
static std::exception const *	get_exception_ (exception_wrapper const *that)
static exception_wrapper	get_exception_ptr_ (exception_wrapper const *that)

Public Attributes
std::exception_ptr	ptr_
std::uintptr_t	exception_or_type_

Static Public Attributes
static VTable const	ops_

Detailed Description

Definition at line 256 of file ExceptionWrapper.h.

Member Function Documentation

std::exception const * folly::exception_wrapper::ExceptionPtr::as_exception_ ( ) const

inline

Definition at line 138 of file ExceptionWrapper-inl.h.

References upload::const.

Referenced by get_exception_().

          {
  return reinterpret_cast<std::exception const*>(exception_or_type_);
}

std::uintptr_t folly::exception_wrapper::ExceptionPtr::as_int_ ( std::exception_ptr const &  ptr, std::exception const &  e  )

inlinestaticnoexcept

Definition at line 99 of file ExceptionWrapper-inl.h.

References upload::const, folly::FOLLY_PACK_ATTR, FOLLY_PACK_PUSH, folly::kMicrosoftAbiVer, and ptr.

Referenced by folly::exception_wrapper::exception_wrapper().

                                    {
  if (!kMicrosoftAbiVer) {
    return reinterpret_cast<std::uintptr_t>(&e);
  } else {
    // On Windows, as of MSVC2017, all thrown exceptions are copied to the stack
    // first. Thus, we cannot depend on exception references associated with an
    // exception_ptr to be live for the duration of the exception_ptr. We need
    // to directly access the heap allocated memory inside the exception_ptr.
    //
    // std::exception_ptr is an opaque reinterpret_cast of
    // std::shared_ptr<__ExceptionPtr>
    // __ExceptionPtr is a non-virtual class with two members, a union and a
    // bool. The union contains the now-undocumented EHExceptionRecord, which
    // contains a struct which contains a void* which points to the heap
    // allocated exception.
    // We derive the offset to pExceptionObject via manual means.
    FOLLY_PACK_PUSH
    struct Win32ExceptionPtr {
      char offset[8 + 4 * sizeof(void*)];
      void* exceptionObject;
    } FOLLY_PACK_ATTR;
    FOLLY_PACK_POP

    auto* win32ExceptionPtr =
        reinterpret_cast<std::shared_ptr<Win32ExceptionPtr> const*>(&ptr)
            ->get();
    return reinterpret_cast<std::uintptr_t>(win32ExceptionPtr->exceptionObject);
  }
}

std::uintptr_t folly::exception_wrapper::ExceptionPtr::as_int_ ( std::exception_ptr const &  ptr, AnyException  e  )

inlinestaticnoexcept

Definition at line 130 of file ExceptionWrapper-inl.h.

                             {
  return reinterpret_cast<std::uintptr_t>(e.typeinfo_) + 1;
}

std::type_info const * folly::exception_wrapper::ExceptionPtr::as_type_ ( ) const

inline

Definition at line 142 of file ExceptionWrapper-inl.h.

References upload::const.

Referenced by type_().

                                                                         {
  return reinterpret_cast<std::type_info const*>(exception_or_type_ - 1);
}

void folly::exception_wrapper::ExceptionPtr::copy_ ( exception_wrapper const *  from, exception_wrapper *  to  )

inlinestatic

Definition at line 146 of file ExceptionWrapper-inl.h.

References folly::exception_wrapper::eptr_.

                           {
  ::new (static_cast<void*>(&to->eptr_)) ExceptionPtr(from->eptr_);
}

void folly::exception_wrapper::ExceptionPtr::delete_ ( exception_wrapper *  that )

inlinestatic

Definition at line 157 of file ExceptionWrapper-inl.h.

References folly::exception_wrapper::eptr_, folly::exception_wrapper::uninit_, and folly::exception_wrapper::vptr_.

                                                                          {
  that->eptr_.~ExceptionPtr();
  that->vptr_ = &uninit_;
}

std::exception const * folly::exception_wrapper::ExceptionPtr::get_exception_ ( exception_wrapper const *  that )

inlinestatic

Definition at line 172 of file ExceptionWrapper-inl.h.

References as_exception_(), folly::exception_wrapper::eptr_, and has_exception_().

                                   {
  return that->eptr_.has_exception_() ? that->eptr_.as_exception_() : nullptr;
}

exception_wrapper folly::exception_wrapper::ExceptionPtr::get_exception_ptr_ ( exception_wrapper const *  that )

inlinestatic

Definition at line 176 of file ExceptionWrapper-inl.h.

                                   {
  return *that;
}

bool folly::exception_wrapper::ExceptionPtr::has_exception_ ( ) const

inline

Definition at line 135 of file ExceptionWrapper-inl.h.

Referenced by get_exception_().

                                                                {
  return 0 == exception_or_type_ % 2;
}

void folly::exception_wrapper::ExceptionPtr::move_ ( exception_wrapper *  from, exception_wrapper *  to  )

inlinestatic

Definition at line 151 of file ExceptionWrapper-inl.h.

References folly::exception_wrapper::eptr_, and folly::gen::move.

                           {
  ::new (static_cast<void*>(&to->eptr_)) ExceptionPtr(std::move(from->eptr_));
  delete_(from);
}

void folly::exception_wrapper::ExceptionPtr::throw_ ( exception_wrapper const *  that )

inlinestatic

Definition at line 161 of file ExceptionWrapper-inl.h.

References folly::exception_wrapper::eptr_, and ptr_.

                                   {
  std::rethrow_exception(that->eptr_.ptr_);
}

std::type_info const * folly::exception_wrapper::ExceptionPtr::type_ ( exception_wrapper const *  that )

inlinestatic

Definition at line 165 of file ExceptionWrapper-inl.h.

References as_type_(), and folly::exception_wrapper::eptr_.

                                   {
  if (auto e = get_exception_(that)) {
    return &typeid(*e);
  }
  return that->eptr_.as_type_();
}

Member Data Documentation

std::uintptr_t folly::exception_wrapper::ExceptionPtr::exception_or_type_

Definition at line 258 of file ExceptionWrapper.h.

exception_wrapper::VTable const folly::exception_wrapper::ExceptionPtr::ops_

static

Initial value:

{
    copy_,
    move_,
    delete_,
    throw_,
    type_,
    get_exception_,
    get_exception_ptr_}

Definition at line 280 of file ExceptionWrapper.h.

Referenced by folly::exception_wrapper::exception_wrapper(), and folly::exception_wrapper::has_exception_ptr().

std::exception_ptr folly::exception_wrapper::ExceptionPtr::ptr_

Definition at line 257 of file ExceptionWrapper.h.

Referenced by folly::exception_wrapper::exception_wrapper(), throw_(), and folly::exception_wrapper::to_exception_ptr().

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The documentation for this struct was generated from the following files:

• proxygen/folly/folly/ExceptionWrapper.h
• proxygen/folly/folly/ExceptionWrapper-inl.h
• proxygen/folly/folly/ExceptionWrapper.cpp