From bf548ce3e67276aa429b462cf41e68891fdf40c2 Mon Sep 17 00:00:00 2001 From: Jonathan Wakely Date: Fri, 3 Dec 2021 11:16:30 +0000 Subject: [PATCH] libstdc++: Simplify emplace member functions in _Rb_tree This introduces a new RAII type to simplify the emplace members which currently use try-catch blocks to deallocate a node if an exception is thrown by the comparisons done during insertion. The new type is created on the stack and manages the allocation of a new node and deallocates it in the destructor if it wasn't inserted into the tree. It also provides helper functions for doing the insertion, releasing ownership of the node to the tree. Also, we don't need to use long qualified names if we put the return type after the nested-name-specifier. libstdc++-v3/ChangeLog: * include/bits/stl_tree.h (_Rb_tree::_Auto_node): Define new RAII helper for creating and inserting new nodes. (_Rb_tree::_M_insert_node): Use trailing-return-type to simplify out-of-line definition. (_Rb_tree::_M_insert_lower_node): Likewise. (_Rb_tree::_M_insert_equal_lower_node): Likewise. (_Rb_tree::_M_emplace_unique): Likewise. Use _Auto_node. (_Rb_tree::_M_emplace_equal): Likewise. (_Rb_tree::_M_emplace_hint_unique): Likewise. (_Rb_tree::_M_emplace_hint_equal): Likewise. --- libstdc++-v3/include/bits/stl_tree.h | 148 ++++++++++++++------------- 1 file changed, 78 insertions(+), 70 deletions(-) diff --git a/libstdc++-v3/include/bits/stl_tree.h b/libstdc++-v3/include/bits/stl_tree.h index 55b8c9c7cb2..336f4ed97b7 100644 --- a/libstdc++-v3/include/bits/stl_tree.h +++ b/libstdc++-v3/include/bits/stl_tree.h @@ -1624,6 +1624,52 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION __y.begin(), __y.end()); } #endif + + private: +#if __cplusplus >= 201103L + // An RAII _Node handle + struct _Auto_node + { + template + _Auto_node(_Rb_tree& __t, _Args&&... __args) + : _M_t(__t), + _M_node(__t._M_create_node(std::forward<_Args>(__args)...)) + { } + + ~_Auto_node() + { + if (_M_node) + _M_t._M_drop_node(_M_node); + } + + _Auto_node(_Auto_node&& __n) + : _M_t(__n._M_t), _M_node(__n._M_node) + { __n._M_node = nullptr; } + + const _Key& + _M_key() const + { return _S_key(_M_node); } + + iterator + _M_insert(pair<_Base_ptr, _Base_ptr> __p) + { + auto __it = _M_t._M_insert_node(__p.first, __p.second, _M_node); + _M_node = nullptr; + return __it; + } + + iterator + _M_insert_equal_lower() + { + auto __it = _M_t._M_insert_equal_lower_node(_M_node); + _M_node = nullptr; + return __it; + } + + _Rb_tree& _M_t; + _Link_type _M_node; + }; +#endif // C++11 }; template= 201103L template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_insert_node(_Base_ptr __x, _Base_ptr __p, _Link_type __z) + -> iterator { bool __insert_left = (__x != 0 || __p == _M_end() || _M_impl._M_key_compare(_S_key(__z), @@ -2342,9 +2389,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_insert_lower_node(_Base_ptr __p, _Link_type __z) + -> iterator { bool __insert_left = (__p == _M_end() || !_M_impl._M_key_compare(_S_key(__p), @@ -2358,9 +2406,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_insert_equal_lower_node(_Link_type __z) + -> iterator { _Link_type __x = _M_begin(); _Base_ptr __y = _M_end(); @@ -2376,100 +2425,59 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION template template - pair::iterator, bool> + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_emplace_unique(_Args&&... __args) + -> pair { - _Link_type __z = _M_create_node(std::forward<_Args>(__args)...); - - __try - { - typedef pair _Res; - auto __res = _M_get_insert_unique_pos(_S_key(__z)); - if (__res.second) - return _Res(_M_insert_node(__res.first, __res.second, __z), true); - - _M_drop_node(__z); - return _Res(iterator(__res.first), false); - } - __catch(...) - { - _M_drop_node(__z); - __throw_exception_again; - } + _Auto_node __z(*this, std::forward<_Args>(__args)...); + auto __res = _M_get_insert_unique_pos(__z._M_key()); + if (__res.second) + return {__z._M_insert(__res), true}; + return {iterator(__res.first), false}; } template template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_emplace_equal(_Args&&... __args) + -> iterator { - _Link_type __z = _M_create_node(std::forward<_Args>(__args)...); - - __try - { - auto __res = _M_get_insert_equal_pos(_S_key(__z)); - return _M_insert_node(__res.first, __res.second, __z); - } - __catch(...) - { - _M_drop_node(__z); - __throw_exception_again; - } + _Auto_node __z(*this, std::forward<_Args>(__args)...); + auto __res = _M_get_insert_equal_pos(__z._M_key()); + return __z._M_insert(__res); } template template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_emplace_hint_unique(const_iterator __pos, _Args&&... __args) + -> iterator { - _Link_type __z = _M_create_node(std::forward<_Args>(__args)...); - - __try - { - auto __res = _M_get_insert_hint_unique_pos(__pos, _S_key(__z)); - - if (__res.second) - return _M_insert_node(__res.first, __res.second, __z); - - _M_drop_node(__z); - return iterator(__res.first); - } - __catch(...) - { - _M_drop_node(__z); - __throw_exception_again; - } + _Auto_node __z(*this, std::forward<_Args>(__args)...); + auto __res = _M_get_insert_hint_unique_pos(__pos, __z._M_key()); + if (__res.second) + return __z._M_insert(__res); + return iterator(__res.first); } template template - typename _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator + auto _Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>:: _M_emplace_hint_equal(const_iterator __pos, _Args&&... __args) + -> iterator { - _Link_type __z = _M_create_node(std::forward<_Args>(__args)...); - - __try - { - auto __res = _M_get_insert_hint_equal_pos(__pos, _S_key(__z)); - - if (__res.second) - return _M_insert_node(__res.first, __res.second, __z); - - return _M_insert_equal_lower_node(__z); - } - __catch(...) - { - _M_drop_node(__z); - __throw_exception_again; - } + _Auto_node __z(*this, std::forward<_Args>(__args)...); + auto __res = _M_get_insert_hint_equal_pos(__pos, __z._M_key()); + if (__res.second) + return __z._M_insert(__res); + return __z._M_insert_equal_lower(); } #endif