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leaf/include/boost/leaf/error.hpp

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#ifndef BOOST_LEAF_ERROR_HPP_INCLUDED
#define BOOST_LEAF_ERROR_HPP_INCLUDED
// Copyright 2018-2025 Emil Dotchevski and Reverge Studios, Inc.
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
#include <boost/leaf/config.hpp>
#include <boost/leaf/detail/optional.hpp>
#include <boost/leaf/detail/function_traits.hpp>
#include <boost/leaf/detail/capture_list.hpp>
#include <boost/leaf/detail/diagnostics_writer.hpp>
////////////////////////////////////////
#if BOOST_LEAF_CFG_STD_SYSTEM_ERROR
#include <system_error>
namespace boost { namespace leaf {
namespace serialization
{
template <class Encoder>
void output(Encoder & e, std::error_code const & x)
{
output_at(e, x.category().name(), "category");
output_at(e, x.value(), "value");
output_at(e, x.message(), "message");
}
template <class Encoder>
void output(Encoder & e, std::error_condition const & x)
{
output_at(e, x.category().name(), "category");
output_at(e, x.value(), "value");
output_at(e, x.message(), "message");
}
}
} }
#endif
////////////////////////////////////////
#define BOOST_LEAF_TOKEN_PASTE(x, y) x ## y
#define BOOST_LEAF_TOKEN_PASTE2(x, y) BOOST_LEAF_TOKEN_PASTE(x, y)
#define BOOST_LEAF_TMP BOOST_LEAF_TOKEN_PASTE2(boost_leaf_tmp_, __LINE__)
#define BOOST_LEAF_ASSIGN(v,r)\
auto && BOOST_LEAF_TMP = r;\
static_assert(::boost::leaf::is_result_type<typename std::decay<decltype(BOOST_LEAF_TMP)>::type>::value,\
"BOOST_LEAF_ASSIGN/BOOST_LEAF_AUTO requires a result object as the second argument (see is_result_type)");\
if( !BOOST_LEAF_TMP )\
return BOOST_LEAF_TMP.error();\
v = std::forward<decltype(BOOST_LEAF_TMP)>(BOOST_LEAF_TMP).value()
#define BOOST_LEAF_AUTO(v, r)\
BOOST_LEAF_ASSIGN(auto v, r)
#if BOOST_LEAF_CFG_GNUC_STMTEXPR
# define BOOST_LEAF_CHECK(r)\
({\
auto && BOOST_LEAF_TMP = (r);\
static_assert(::boost::leaf::is_result_type<typename std::decay<decltype(BOOST_LEAF_TMP)>::type>::value,\
"BOOST_LEAF_CHECK requires a result object (see is_result_type)");\
if( !BOOST_LEAF_TMP )\
return BOOST_LEAF_TMP.error();\
std::move(BOOST_LEAF_TMP);\
}).value()
#else // #if BOOST_LEAF_CFG_GNUC_STMTEXPR
# define BOOST_LEAF_CHECK(r)\
{\
auto && BOOST_LEAF_TMP = (r);\
static_assert(::boost::leaf::is_result_type<typename std::decay<decltype(BOOST_LEAF_TMP)>::type>::value,\
"BOOST_LEAF_CHECK requires a result object (see is_result_type)");\
if( !BOOST_LEAF_TMP )\
return BOOST_LEAF_TMP.error();\
}
#endif // #else (#if BOOST_LEAF_CFG_GNUC_STMTEXPR)
#define BOOST_LEAF_NEW_ERROR ::boost::leaf::detail::inject_loc{__FILE__,__LINE__,__FUNCTION__}+::boost::leaf::new_error
namespace boost { namespace leaf {
struct e_source_location
{
char const * file;
int line;
char const * function;
template <class CharT, class Traits>
friend std::ostream & operator<<(std::basic_ostream<CharT, Traits> & os, e_source_location const & x)
{
return os << x.file << '(' << x.line << ") in function " << x.function;
}
template <class Encoder>
friend void output( Encoder & e, e_source_location const & x )
{
output_at(e, x.file, "file");
output_at(e, x.line, "line");
output_at(e, x.function, "function");
}
};
template <>
struct show_in_diagnostics<e_source_location>: std::false_type
{
};
////////////////////////////////////////
namespace serialization
{
template <class Encoder, class T, class... Unused>
typename std::enable_if<std::is_base_of<detail::encoder, Encoder>::value>::type
serialize(Encoder &, T const &, char const *, Unused && ...)
{
}
}
namespace detail
{
template <class T>
void serialize_(diagnostics_writer & e, T const & x)
{
e.write(x);
}
template <class T>
void serialize_(encoder & e, T const & x)
{
using namespace serialization;
char zstr[1024];
serialize(e, x, to_zstr(zstr, get_type_name<T>()));
if( diagnostics_writer * dw = e.get<diagnostics_writer>() )
dw->write(x);
}
}
////////////////////////////////////////
namespace detail
{
template <class E>
class slot:
optional<E>
{
static_assert(std::is_same<E, typename std::decay<E>::type>::value, "E must be decayed for slot<E>");
slot( slot const & ) = delete;
slot & operator=( slot const & ) = delete;
using impl = optional<E>;
slot<E> * prev_;
public:
BOOST_LEAF_CONSTEXPR slot():
prev_(nullptr)
{
tls::reserve_ptr<slot<E>>();
}
template <class T>
BOOST_LEAF_CONSTEXPR slot( int key, T && e ):
optional<E>(key, std::forward<T>(e)),
prev_(nullptr)
{
tls::reserve_ptr<slot<E>>();
}
BOOST_LEAF_CONSTEXPR slot( slot && x ) noexcept:
optional<E>(std::move(x)),
prev_(nullptr)
{
BOOST_LEAF_ASSERT(x.prev_ == nullptr);
}
~slot() noexcept
{
BOOST_LEAF_ASSERT(tls::read_ptr<slot<E>>() != this);
}
void activate() noexcept
{
prev_ = tls::read_ptr<slot<E>>();
tls::write_ptr<slot<E>>(this);
}
void deactivate() const noexcept
{
tls::write_ptr<slot<E>>(prev_);
}
void unload( int err_id ) noexcept(!BOOST_LEAF_CFG_CAPTURE);
template <class Encoder,class ErrorID>
void serialize_to(Encoder & e, ErrorID id) const
{
static_assert(std::is_base_of<encoder, Encoder>::value, "Encoder must derive from detail::encoder");
if( int k = this->key() )
{
if( id && id.value() != k )
return;
serialize_(e, value(k));
}
}
using impl::load;
using impl::has_value;
using impl::value;
}; // template slot
} // namespace detail
////////////////////////////////////////
#if BOOST_LEAF_CFG_CAPTURE
namespace detail
{
template <class E>
struct capturing_slot_node_allocator;
class dynamic_allocator:
capture_list
{
dynamic_allocator( dynamic_allocator const & ) = delete;
dynamic_allocator & operator=( dynamic_allocator const & ) = delete;
template <class>
friend struct capturing_slot_node_allocator;
class capturing_node:
public capture_list::node
{
protected:
BOOST_LEAF_CONSTEXPR explicit capturing_node( capture_list::node * * & last ) noexcept:
node(last)
{
BOOST_LEAF_ASSERT(last == &next_);
BOOST_LEAF_ASSERT(next_ == nullptr);
}
public:
virtual void deactivate() const noexcept = 0;
};
template <class E>
class capturing_slot_node final:
public slot<E>,
public capturing_node
{
using impl = slot<E>;
capturing_slot_node( capturing_slot_node const & ) = delete;
capturing_slot_node & operator=( capturing_slot_node const & ) = delete;
void deactivate() const noexcept override
{
impl::deactivate();
}
void unload( int err_id ) override
{
impl::unload(err_id);
}
void serialize_to_(encoder & e, error_id const & id) const override
{
impl::serialize_to(e, id);
}
public:
BOOST_LEAF_CONSTEXPR explicit capturing_slot_node( capture_list::node * * & last ):
capturing_node(last)
{
BOOST_LEAF_ASSERT(last == &next_);
BOOST_LEAF_ASSERT(next_ == nullptr);
}
template <class T>
BOOST_LEAF_CONSTEXPR capturing_slot_node( capture_list::node * * & last, int err_id, T && e ):
slot<E>(err_id, std::forward<T>(e)),
capturing_node(last)
{
BOOST_LEAF_ASSERT(last == &next_);
BOOST_LEAF_ASSERT(next_ == nullptr);
}
};
#ifndef BOOST_LEAF_NO_EXCEPTIONS
class capturing_exception_node final:
public capturing_node
{
capturing_exception_node( capturing_exception_node const & ) = delete;
capturing_exception_node & operator=( capturing_exception_node const & ) = delete;
void deactivate() const noexcept override
{
BOOST_LEAF_ASSERT(0);
}
void unload( int ) override
{
std::rethrow_exception(ex_);
}
void serialize_to_(encoder &, error_id const &) const override
{
}
std::exception_ptr const ex_;
public:
capturing_exception_node( capture_list::node * * & last, std::exception_ptr && ex ) noexcept:
capturing_node(last),
ex_(std::move(ex))
{
BOOST_LEAF_ASSERT(last == &next_);
BOOST_LEAF_ASSERT(ex_);
}
};
#endif // #ifndef BOOST_LEAF_NO_EXCEPTIONS
node * * last_;
public:
dynamic_allocator() noexcept:
capture_list(nullptr),
last_(&first_)
{
BOOST_LEAF_ASSERT(first_ == nullptr);
}
dynamic_allocator( dynamic_allocator && other ) noexcept:
capture_list(std::move(other)),
last_(other.last_ == &other.first_? &first_ : other.last_)
{
BOOST_LEAF_ASSERT(last_ != nullptr);
BOOST_LEAF_ASSERT(*last_ == nullptr);
BOOST_LEAF_ASSERT(other.first_ == nullptr);
other.last_ = &other.first_;
}
template <class E>
slot<E> * alloc()
{
BOOST_LEAF_ASSERT(last_ != nullptr);
BOOST_LEAF_ASSERT(*last_ == nullptr);
BOOST_LEAF_ASSERT(tls::read_ptr<slot<E>>() == nullptr);
capturing_slot_node<E> * csn = capturing_slot_node_allocator<E>::new_(last_);
csn->activate();
return csn;
}
template <class E>
slot<E> * reserve()
{
if( slot<E> * p = tls::read_ptr<slot<E>>() )
return p;
else
return alloc<E>();
}
void deactivate() const noexcept
{
for_each(
[]( capture_list::node const & n )
{
static_cast<capturing_node const &>(n).deactivate();
} );
}
template <class LeafResult>
LeafResult extract_capture_list(int err_id)
{
#ifndef BOOST_LEAF_NO_EXCEPTIONS
if( std::exception_ptr ex = std::current_exception() )
(void) new capturing_exception_node(last_, std::move(ex));
#endif
detail::capture_list::node * const f = first_;
first_ = nullptr;
last_ = &first_;
return { err_id, capture_list(f) };
}
using capture_list::unload;
using capture_list::serialize_to;
}; // class dynamic_allocator
template <class E>
struct capturing_slot_node_allocator
{
template <class... A>
static dynamic_allocator::capturing_slot_node<E> * new_( A && ... a )
{
return new dynamic_allocator::capturing_slot_node<E>(std::forward<A>(a)...);
}
static void delete_( dynamic_allocator::capturing_slot_node<E> * p ) noexcept
{
delete p;
}
};
template <>
class slot<dynamic_allocator>
{
slot( slot const & ) = delete;
slot & operator=( slot const & ) = delete;
dynamic_allocator da_;
slot * prev_;
public:
slot() noexcept:
prev_(nullptr)
{
tls::reserve_ptr<slot<dynamic_allocator>>();
}
slot( slot && x ) noexcept:
da_(std::move(x.da_)),
prev_(nullptr)
{
BOOST_LEAF_ASSERT(x.prev_ == nullptr);
}
~slot() noexcept
{
BOOST_LEAF_ASSERT(tls::read_ptr<slot<dynamic_allocator>>() != this);
}
dynamic_allocator const & get() const noexcept
{
return da_;
}
dynamic_allocator & get() noexcept
{
return da_;
}
void activate() noexcept
{
prev_ = tls::read_ptr<slot<dynamic_allocator>>();
tls::write_ptr<slot<dynamic_allocator>>(this);
}
void deactivate() const noexcept
{
da_.deactivate();
tls::write_ptr<slot<dynamic_allocator>>(prev_);
}
void unload( int err_id )
{
BOOST_LEAF_ASSERT(err_id);
da_.unload(err_id);
}
template <class ErrorID>
void serialize_to(encoder &, ErrorID) const
{
}
}; // slot specialization for dynamic_allocator
} // namespace detail
#endif // #if BOOST_LEAF_CFG_CAPTURE
////////////////////////////////////////
namespace detail
{
#if BOOST_LEAF_CFG_CAPTURE
inline dynamic_allocator * get_dynamic_allocator() noexcept
{
if( slot<dynamic_allocator> * sl = tls::read_ptr<slot<dynamic_allocator>>() )
return &sl->get();
return nullptr;
}
#endif
template <class E>
inline slot<E> * get_slot() noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
static_assert(!std::is_pointer<E>::value, "Error objects of pointer types are not allowed");
static_assert(!std::is_same<E, error_id>::value, "Error objects of type error_id are not allowed");
if( slot<E> * p = tls::read_ptr<slot<E>>() )
return p;
#if BOOST_LEAF_CFG_CAPTURE
if( dynamic_allocator * da = get_dynamic_allocator() )
return da->alloc<E>();
#endif
return nullptr;
}
template <class E>
inline void slot<E>::unload( int err_id ) noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
BOOST_LEAF_ASSERT(err_id);
if( this->key() != err_id )
return;
if( impl * p = get_slot<E>() )
if( !p->has_value(err_id) )
*p = std::move(*this);
}
template <class E>
BOOST_LEAF_CONSTEXPR inline int load_slot( int err_id, E && e ) noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
using E_decayed = typename std::decay<E>::type;
BOOST_LEAF_ASSERT((err_id&3) == 1);
if( slot<E_decayed> * p = get_slot<E_decayed>() )
(void) p->load(err_id, std::forward<E>(e));
return 0;
}
template <class F>
BOOST_LEAF_CONSTEXPR inline int load_slot_deferred( int err_id, F && f )
{
using E = typename function_traits<F>::return_type;
using E_decayed = typename std::decay<E>::type;
BOOST_LEAF_ASSERT((err_id&3) == 1);
if( slot<E_decayed> * p = get_slot<E_decayed>() )
(void) p->load(err_id, std::forward<F>(f)());
return 0;
}
template <class F>
BOOST_LEAF_CONSTEXPR inline int load_slot_accumulate( int err_id, F && f )
{
static_assert(function_traits<F>::arity == 1, "Lambdas passed to accumulate must take a single e-type argument by reference");
using E = fn_arg_type<F,0>;
using E_decayed = typename std::decay<E>::type;
BOOST_LEAF_ASSERT((err_id&3) == 1);
if( slot<E_decayed> * p = get_slot<E_decayed>() )
if( E_decayed * v = p->has_value(err_id) )
(void) std::forward<F>(f)(*v);
else
(void) std::forward<F>(f)(p->load(err_id, E_decayed()));
return 0;
}
} // namespace detail
////////////////////////////////////////
namespace detail
{
template <class T, int Arity = function_traits<T>::arity>
struct load_item
{
static_assert(Arity == 0 || Arity == 1, "If a functions is passed to new_error or load, it must take zero or one argument");
};
template <class E>
struct load_item<E, -1>
{
BOOST_LEAF_CONSTEXPR static int load_( int err_id, E && e )
{
return load_slot(err_id, std::forward<E>(e));
}
};
template <class F>
struct load_item<F, 0>
{
BOOST_LEAF_CONSTEXPR static int load_( int err_id, F && f )
{
return load_slot_deferred(err_id, std::forward<F>(f));
}
};
template <class F>
struct load_item<F, 1>
{
BOOST_LEAF_CONSTEXPR static int load_( int err_id, F && f )
{
return load_slot_accumulate(err_id, std::forward<F>(f));
}
};
}
////////////////////////////////////////
namespace detail
{
inline int current_id() noexcept
{
unsigned id = tls::read_current_error_id();
BOOST_LEAF_ASSERT(id == 0 || (id&3) == 1);
return int(id);
}
inline int new_id() noexcept
{
unsigned id = tls::generate_next_error_id();
tls::write_current_error_id(id);
return int(id);
}
inline int start_new_error() noexcept
{
return new_id();
}
struct inject_loc
{
char const * file;
int line;
char const * fn;
template <class T>
friend T operator+( inject_loc loc, T && x ) noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
x.load_source_location_(loc.file, loc.line, loc.fn);
return std::move(x);
}
};
} // namespace detail
#if BOOST_LEAF_CFG_STD_SYSTEM_ERROR
namespace detail
{
class leaf_error_category final:
public std::error_category
{
bool equivalent( int, std::error_condition const & ) const noexcept override { return false; }
bool equivalent( std::error_code const &, int ) const noexcept override { return false; }
char const * name() const noexcept override { return "LEAF error"; }
std::string message( int ) const override { return name(); }
public:
~leaf_error_category() noexcept override { }
};
template <class=void>
struct get_leaf_error_category
{
static leaf_error_category cat;
};
template <class T>
leaf_error_category get_leaf_error_category<T>::cat;
inline int import_error_code( std::error_code const & ec ) noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
if( int err_id = ec.value() )
{
std::error_category const & cat = get_leaf_error_category<>::cat;
if( &ec.category() == &cat )
{
BOOST_LEAF_ASSERT((err_id&3) == 1);
return (err_id&~3)|1;
}
else
{
err_id = start_new_error();
(void) load_slot(err_id, ec);
return (err_id&~3)|1;
}
}
else
return 0;
}
} // namespace detail
inline bool is_error_id( std::error_code const & ec ) noexcept
{
bool res = (&ec.category() == &detail::get_leaf_error_category<>::cat);
BOOST_LEAF_ASSERT(!res || !ec.value() || ((ec.value()&3) == 1));
return res;
}
#endif // #if BOOST_LEAF_CFG_STD_SYSTEM_ERROR
////////////////////////////////////////
namespace detail
{
BOOST_LEAF_CONSTEXPR error_id make_error_id(int) noexcept;
}
class error_id
{
friend error_id BOOST_LEAF_CONSTEXPR detail::make_error_id(int) noexcept;
int value_;
BOOST_LEAF_CONSTEXPR explicit error_id( int value ) noexcept:
value_(value)
{
BOOST_LEAF_ASSERT(value_ == 0 || ((value_&3) == 1));
}
public:
BOOST_LEAF_CONSTEXPR error_id() noexcept:
value_(0)
{
}
#if BOOST_LEAF_CFG_STD_SYSTEM_ERROR
explicit error_id( std::error_code const & ec ) noexcept(!BOOST_LEAF_CFG_CAPTURE):
value_(detail::import_error_code(std::error_code(ec)))
{
BOOST_LEAF_ASSERT(!value_ || ((value_&3) == 1));
}
template <class Enum>
error_id( Enum e, typename std::enable_if<std::is_error_code_enum<Enum>::value, int>::type = 0 ) noexcept(!BOOST_LEAF_CFG_CAPTURE):
value_(detail::import_error_code(e))
{
}
template <class T, typename std::enable_if<std::is_constructible<T, std::error_code>::value, int>::type = 0>
operator T() const noexcept
{
return std::error_code(value_, detail::get_leaf_error_category<>::cat);
}
#endif // #if BOOST_LEAF_CFG_STD_SYSTEM_ERROR
BOOST_LEAF_CONSTEXPR error_id load() const noexcept
{
return *this;
}
template <class Item>
BOOST_LEAF_CONSTEXPR error_id load(Item && item) const
{
if (int err_id = value())
{
int const unused[] = { 42, detail::load_item<Item>::load_(err_id, std::forward<Item>(item)) };
(void)unused;
}
return *this;
}
template <class... Item>
BOOST_LEAF_CONSTEXPR error_id load( Item && ... item ) const
{
if( int err_id = value() )
{
int const unused[] = { 42, detail::load_item<Item>::load_(err_id, std::forward<Item>(item))... };
(void) unused;
}
return *this;
}
BOOST_LEAF_CONSTEXPR int value() const noexcept
{
BOOST_LEAF_ASSERT(value_ == 0 || ((value_&3) == 1));
return value_;
}
BOOST_LEAF_CONSTEXPR explicit operator bool() const noexcept
{
return value_ != 0;
}
BOOST_LEAF_CONSTEXPR friend bool operator==( error_id a, error_id b ) noexcept
{
return a.value_ == b.value_;
}
BOOST_LEAF_CONSTEXPR friend bool operator!=( error_id a, error_id b ) noexcept
{
return !(a == b);
}
BOOST_LEAF_CONSTEXPR friend bool operator<( error_id a, error_id b ) noexcept
{
return a.value_ < b.value_;
}
template <class CharT, class Traits>
friend std::ostream & operator<<( std::basic_ostream<CharT, Traits> & os, error_id x )
{
return os << (x.value_ / 4);
}
template <class Encoder>
friend void output( Encoder & e, error_id x )
{
output(e, x.value_ / 4);
}
BOOST_LEAF_CONSTEXPR void load_source_location_( char const * file, int line, char const * function ) const noexcept(!BOOST_LEAF_CFG_CAPTURE)
{
BOOST_LEAF_ASSERT(file&&*file);
BOOST_LEAF_ASSERT(line>0);
BOOST_LEAF_ASSERT(function&&*function);
BOOST_LEAF_ASSERT(value_);
(void) load(e_source_location {file,line,function});
}
}; // class error_id
namespace detail
{
BOOST_LEAF_CONSTEXPR inline error_id make_error_id( int err_id ) noexcept
{
BOOST_LEAF_ASSERT(err_id == 0 || (err_id&3) == 1);
return error_id((err_id&~3)|1);
}
}
BOOST_LEAF_ATTRIBUTE_NODISCARD inline error_id new_error()
{
return detail::make_error_id(detail::start_new_error());
}
template <class... Item>
BOOST_LEAF_ATTRIBUTE_NODISCARD inline error_id new_error( Item && ... item )
{
return detail::make_error_id(detail::start_new_error()).load(std::forward<Item>(item)...);
}
inline error_id current_error() noexcept
{
return detail::make_error_id(detail::current_id());
}
////////////////////////////////////////
template <class R>
struct is_result_type: std::false_type
{
};
template <class R>
struct is_result_type<R const>: is_result_type<R>
{
};
} } // namespace boost::leaf
#endif // #ifndef BOOST_LEAF_ERROR_HPP_INCLUDED