d72607e9e2
C++14 support[1], adds more C++1z features[2], and fixes the following
LWG issues[3]:
1450: Contradiction in regex_constants
2003: String exception inconsistency in erase.
2075: Progress guarantees, lock-free property, and scheduling
assumptions
2104: unique_lock move-assignment should not be noexcept
2112: User-defined classes that cannot be derived from
2132: std::function ambiguity
2135: Unclear requirement for exceptions thrown in
condition_variable::wait()
2142: packaged_task::operator() synchronization too broad?
2182: Container::[const_]reference types are misleadingly specified
2186: Incomplete action on async/launch::deferred
2188: Reverse iterator does not fully support targets that overload
operator&
2193: Default constructors for standard library containers are explicit
2205: Problematic postconditions of regex_match and regex_search
2213: Return value of std::regex_replace
2240: Probable misuse of term "function scope" in [thread.condition]
2252: Strong guarantee on vector::push_back() still broken with C++11?
2257: Simplify container requirements with the new algorithms
2258: a.erase(q1, q2) unable to directly return q2
2263: Comparing iterators and allocator pointers with different
const-character
2268: Setting a default argument in the declaration of a member
function assign of std::basic_string
2271: regex_traits::lookup_classname specification unclear
2272: quoted should use char_traits::eq for character comparison
2278: User-defined literals for Standard Library types
2280: begin / end for arrays should be constexpr and noexcept
2285: make_reverse_iterator
2288: Inconsistent requirements for shared mutexes
2291: std::hash is vulnerable to collision DoS attack
2293: Wrong facet used by num_put::do_put
2299: Effects of inaccessible key_compare::is_transparent type are not
clear
2301: Why is std::tie not constexpr?
2304: Complexity of count in unordered associative containers
2306: match_results::reference should be value_type&, not const
value_type&
2308: Clarify container destructor requirements w.r.t. std::array
2313: tuple_size should always derive from integral_constant<size_t, N>
2314: apply() should return decltype(auto) and use decay_t before
tuple_size
2315: weak_ptr should be movable
2316: weak_ptr::lock() should be atomic
2317: The type property queries should be UnaryTypeTraits returning
size_t
2320: select_on_container_copy_construction() takes allocators, not
containers
2322: Associative(initializer_list, stuff) constructors are
underspecified
2323: vector::resize(n, t)'s specification should be simplified
2324: Insert iterator constructors should use addressof()
2329: regex_match()/regex_search() with match_results should forbid
temporary strings
2330: regex("meow", regex::icase) is technically forbidden but should
be permitted
2332: regex_iterator/regex_token_iterator should forbid temporary
regexes
2339: Wording issue in nth_element
2341: Inconsistency between basic_ostream::seekp(pos) and
basic_ostream::seekp(off, dir)
2344: quoted()'s interaction with padding is unclear
2346: integral_constant's member functions should be marked noexcept
2350: min, max, and minmax should be constexpr
2356: Stability of erasure in unordered associative containers
2357: Remaining "Assignable" requirement
2359: How does regex_constants::nosubs affect basic_regex::mark_count()?
2360: reverse_iterator::operator*() is unimplementable
[1] http://libcxx.llvm.org/cxx1y_status.html
[2] http://libcxx.llvm.org/cxx1z_status.html
[3] http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html
Exp-run: antoine
MFC after: 1 month
426 lines
12 KiB
C++
426 lines
12 KiB
C++
// -*- C++ -*-
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//===------------------------ shared_mutex --------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP_SHARED_MUTEX
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#define _LIBCPP_SHARED_MUTEX
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/*
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shared_mutex synopsis
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// C++1y
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namespace std
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{
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class shared_timed_mutex
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{
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public:
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shared_timed_mutex();
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~shared_timed_mutex();
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shared_timed_mutex(const shared_timed_mutex&) = delete;
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shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
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// Exclusive ownership
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void lock(); // blocking
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bool try_lock();
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template <class Rep, class Period>
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
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template <class Clock, class Duration>
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
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void unlock();
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// Shared ownership
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void lock_shared(); // blocking
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bool try_lock_shared();
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template <class Rep, class Period>
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bool
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try_lock_shared_for(const chrono::duration<Rep, Period>& rel_time);
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template <class Clock, class Duration>
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bool
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try_lock_shared_until(const chrono::time_point<Clock, Duration>& abs_time);
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void unlock_shared();
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};
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template <class Mutex>
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class shared_lock
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{
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public:
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typedef Mutex mutex_type;
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// Shared locking
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shared_lock() noexcept;
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explicit shared_lock(mutex_type& m); // blocking
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shared_lock(mutex_type& m, defer_lock_t) noexcept;
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shared_lock(mutex_type& m, try_to_lock_t);
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shared_lock(mutex_type& m, adopt_lock_t);
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template <class Clock, class Duration>
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shared_lock(mutex_type& m,
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const chrono::time_point<Clock, Duration>& abs_time);
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template <class Rep, class Period>
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shared_lock(mutex_type& m,
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const chrono::duration<Rep, Period>& rel_time);
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~shared_lock();
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shared_lock(shared_lock const&) = delete;
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shared_lock& operator=(shared_lock const&) = delete;
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shared_lock(shared_lock&& u) noexcept;
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shared_lock& operator=(shared_lock&& u) noexcept;
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void lock(); // blocking
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bool try_lock();
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template <class Rep, class Period>
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
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template <class Clock, class Duration>
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
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void unlock();
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// Setters
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void swap(shared_lock& u) noexcept;
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mutex_type* release() noexcept;
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// Getters
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bool owns_lock() const noexcept;
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explicit operator bool () const noexcept;
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mutex_type* mutex() const noexcept;
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};
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template <class Mutex>
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void swap(shared_lock<Mutex>& x, shared_lock<Mutex>& y) noexcept;
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} // std
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*/
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#include <__config>
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#if _LIBCPP_STD_VER > 11 || defined(_LIBCPP_BUILDING_SHARED_MUTEX)
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#include <__mutex_base>
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#include <__undef_min_max>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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#pragma GCC system_header
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#endif
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#ifdef _LIBCPP_HAS_NO_THREADS
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#error <shared_mutex> is not supported on this single threaded system
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#else // !_LIBCPP_HAS_NO_THREADS
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_LIBCPP_BEGIN_NAMESPACE_STD
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class _LIBCPP_TYPE_VIS shared_timed_mutex
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{
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mutex __mut_;
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condition_variable __gate1_;
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condition_variable __gate2_;
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unsigned __state_;
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static const unsigned __write_entered_ = 1U << (sizeof(unsigned)*__CHAR_BIT__ - 1);
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static const unsigned __n_readers_ = ~__write_entered_;
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public:
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shared_timed_mutex();
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_LIBCPP_INLINE_VISIBILITY ~shared_timed_mutex() = default;
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shared_timed_mutex(const shared_timed_mutex&) = delete;
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shared_timed_mutex& operator=(const shared_timed_mutex&) = delete;
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// Exclusive ownership
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void lock();
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bool try_lock();
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template <class _Rep, class _Period>
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_LIBCPP_INLINE_VISIBILITY
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bool
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try_lock_for(const chrono::duration<_Rep, _Period>& __rel_time)
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{
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return try_lock_until(chrono::steady_clock::now() + __rel_time);
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}
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template <class _Clock, class _Duration>
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bool
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try_lock_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
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void unlock();
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// Shared ownership
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void lock_shared();
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bool try_lock_shared();
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template <class _Rep, class _Period>
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_LIBCPP_INLINE_VISIBILITY
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bool
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try_lock_shared_for(const chrono::duration<_Rep, _Period>& __rel_time)
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{
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return try_lock_shared_until(chrono::steady_clock::now() + __rel_time);
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}
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template <class _Clock, class _Duration>
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bool
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try_lock_shared_until(const chrono::time_point<_Clock, _Duration>& __abs_time);
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void unlock_shared();
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};
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template <class _Clock, class _Duration>
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bool
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shared_timed_mutex::try_lock_until(
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const chrono::time_point<_Clock, _Duration>& __abs_time)
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{
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unique_lock<mutex> __lk(__mut_);
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if (__state_ & __write_entered_)
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{
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while (true)
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{
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cv_status __status = __gate1_.wait_until(__lk, __abs_time);
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if ((__state_ & __write_entered_) == 0)
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break;
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if (__status == cv_status::timeout)
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return false;
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}
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}
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__state_ |= __write_entered_;
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if (__state_ & __n_readers_)
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{
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while (true)
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{
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cv_status __status = __gate2_.wait_until(__lk, __abs_time);
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if ((__state_ & __n_readers_) == 0)
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break;
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if (__status == cv_status::timeout)
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{
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__state_ &= ~__write_entered_;
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return false;
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}
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}
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}
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return true;
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}
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template <class _Clock, class _Duration>
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bool
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shared_timed_mutex::try_lock_shared_until(
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const chrono::time_point<_Clock, _Duration>& __abs_time)
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{
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unique_lock<mutex> __lk(__mut_);
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if ((__state_ & __write_entered_) || (__state_ & __n_readers_) == __n_readers_)
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{
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while (true)
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{
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cv_status status = __gate1_.wait_until(__lk, __abs_time);
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if ((__state_ & __write_entered_) == 0 &&
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(__state_ & __n_readers_) < __n_readers_)
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break;
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if (status == cv_status::timeout)
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return false;
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}
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}
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unsigned __num_readers = (__state_ & __n_readers_) + 1;
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__state_ &= ~__n_readers_;
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__state_ |= __num_readers;
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return true;
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}
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template <class _Mutex>
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class shared_lock
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{
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public:
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typedef _Mutex mutex_type;
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private:
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mutex_type* __m_;
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bool __owns_;
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public:
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_LIBCPP_INLINE_VISIBILITY
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shared_lock() _NOEXCEPT
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: __m_(nullptr),
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__owns_(false)
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{}
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_LIBCPP_INLINE_VISIBILITY
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explicit shared_lock(mutex_type& __m)
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: __m_(&__m),
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__owns_(true)
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{__m_->lock_shared();}
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(mutex_type& __m, defer_lock_t) _NOEXCEPT
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: __m_(&__m),
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__owns_(false)
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{}
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(mutex_type& __m, try_to_lock_t)
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: __m_(&__m),
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__owns_(__m.try_lock_shared())
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{}
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(mutex_type& __m, adopt_lock_t)
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: __m_(&__m),
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__owns_(true)
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{}
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template <class _Clock, class _Duration>
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(mutex_type& __m,
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const chrono::time_point<_Clock, _Duration>& __abs_time)
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: __m_(&__m),
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__owns_(__m.try_lock_shared_until(__abs_time))
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{}
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template <class _Rep, class _Period>
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(mutex_type& __m,
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const chrono::duration<_Rep, _Period>& __rel_time)
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: __m_(&__m),
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__owns_(__m.try_lock_shared_for(__rel_time))
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{}
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_LIBCPP_INLINE_VISIBILITY
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~shared_lock()
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{
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if (__owns_)
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__m_->unlock_shared();
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}
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shared_lock(shared_lock const&) = delete;
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shared_lock& operator=(shared_lock const&) = delete;
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_LIBCPP_INLINE_VISIBILITY
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shared_lock(shared_lock&& __u) _NOEXCEPT
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: __m_(__u.__m_),
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__owns_(__u.__owns_)
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{
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__u.__m_ = nullptr;
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__u.__owns_ = false;
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}
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_LIBCPP_INLINE_VISIBILITY
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shared_lock& operator=(shared_lock&& __u) _NOEXCEPT
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{
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if (__owns_)
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__m_->unlock_shared();
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__m_ = nullptr;
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__owns_ = false;
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__m_ = __u.__m_;
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__owns_ = __u.__owns_;
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__u.__m_ = nullptr;
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__u.__owns_ = false;
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return *this;
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}
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void lock();
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bool try_lock();
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template <class Rep, class Period>
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bool try_lock_for(const chrono::duration<Rep, Period>& rel_time);
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template <class Clock, class Duration>
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bool try_lock_until(const chrono::time_point<Clock, Duration>& abs_time);
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void unlock();
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// Setters
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_LIBCPP_INLINE_VISIBILITY
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void swap(shared_lock& __u) _NOEXCEPT
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{
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_VSTD::swap(__m_, __u.__m_);
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_VSTD::swap(__owns_, __u.__owns_);
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}
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_LIBCPP_INLINE_VISIBILITY
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mutex_type* release() _NOEXCEPT
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{
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mutex_type* __m = __m_;
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__m_ = nullptr;
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__owns_ = false;
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return __m;
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}
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// Getters
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_LIBCPP_INLINE_VISIBILITY
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bool owns_lock() const _NOEXCEPT {return __owns_;}
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_LIBCPP_INLINE_VISIBILITY
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explicit operator bool () const _NOEXCEPT {return __owns_;}
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_LIBCPP_INLINE_VISIBILITY
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mutex_type* mutex() const _NOEXCEPT {return __m_;}
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};
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template <class _Mutex>
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void
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shared_lock<_Mutex>::lock()
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{
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if (__m_ == nullptr)
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__throw_system_error(EPERM, "shared_lock::lock: references null mutex");
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if (__owns_)
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__throw_system_error(EDEADLK, "shared_lock::lock: already locked");
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__m_->lock_shared();
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__owns_ = true;
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}
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template <class _Mutex>
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bool
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shared_lock<_Mutex>::try_lock()
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{
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if (__m_ == nullptr)
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__throw_system_error(EPERM, "shared_lock::try_lock: references null mutex");
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if (__owns_)
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__throw_system_error(EDEADLK, "shared_lock::try_lock: already locked");
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__owns_ = __m_->try_lock_shared();
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return __owns_;
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}
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template <class _Mutex>
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template <class _Rep, class _Period>
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bool
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shared_lock<_Mutex>::try_lock_for(const chrono::duration<_Rep, _Period>& __d)
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{
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if (__m_ == nullptr)
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__throw_system_error(EPERM, "shared_lock::try_lock_for: references null mutex");
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if (__owns_)
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__throw_system_error(EDEADLK, "shared_lock::try_lock_for: already locked");
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__owns_ = __m_->try_lock_shared_for(__d);
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return __owns_;
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}
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template <class _Mutex>
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template <class _Clock, class _Duration>
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bool
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shared_lock<_Mutex>::try_lock_until(const chrono::time_point<_Clock, _Duration>& __t)
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{
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if (__m_ == nullptr)
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__throw_system_error(EPERM, "shared_lock::try_lock_until: references null mutex");
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if (__owns_)
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__throw_system_error(EDEADLK, "shared_lock::try_lock_until: already locked");
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__owns_ = __m_->try_lock_shared_until(__t);
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return __owns_;
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}
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template <class _Mutex>
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void
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shared_lock<_Mutex>::unlock()
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{
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if (!__owns_)
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__throw_system_error(EPERM, "shared_lock::unlock: not locked");
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__m_->unlock_shared();
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__owns_ = false;
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}
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template <class _Mutex>
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inline _LIBCPP_INLINE_VISIBILITY
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void
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swap(shared_lock<_Mutex>& __x, shared_lock<_Mutex>& __y) _NOEXCEPT
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{__x.swap(__y);}
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_LIBCPP_END_NAMESPACE_STD
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#endif // !_LIBCPP_HAS_NO_THREADS
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#endif // _LIBCPP_STD_VER > 11
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#endif // _LIBCPP_SHARED_MUTEX
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