15456637126

Committed 05 Jun 2025 01:56AM UTC coverage: 87.98%. First build

Build # 15456637126

Build Type

Pull #336

github

Committed by

web-flow

Commit Message

Merge e004b4477 into f0cccaaf4

Pull Request Pull Request #336: coro::ring_buffer use coro::mutex instead of std::mutex

Run Details

79 of 82 new or added lines in 4 files covered. (96.34%)

1581 of 1797 relevant lines covered (87.98%)

5540199.55 hits per line

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97.44

/src/mutex.cpp

#include "coro/detail/awaiter_list.hpp"
#include "coro/mutex.hpp"

namespace coro
{
namespace detail
{
auto lock_operation_base::await_ready() const noexcept -> bool
{
    return m_mutex.try_lock();
}

auto lock_operation_base::await_suspend(std::coroutine_handle<> awaiting_coroutine) noexcept -> bool
{
    m_awaiting_coroutine = awaiting_coroutine;
    auto& state = m_mutex.m_state;
    void* current = state.load(std::memory_order::acquire);
    const void* unlocked_value = m_mutex.unlocked_value();
    do
    {
        // While trying to suspend the lock can become available, if so attempt to grab it and then don't suspend.
        // If the lock never becomes available then we place ourself at the head of the waiter list and suspend.

        if (current == unlocked_value)
        {
            // The lock has become available, try and lock.
            if (state.compare_exchange_weak(current, nullptr, std::memory_order::acq_rel, std::memory_order::acquire))
            {
                // We've acquired the lock, don't suspend.
                m_awaiting_coroutine = nullptr;
                return false;
            }
        }
        else // if (current == nullptr || current is of type lock_operation_base*)
        {
            // The lock is still owned, attempt to add ourself as a waiter.
            m_next = static_cast<lock_operation_base*>(current);
            if (state.compare_exchange_weak(current, static_cast<void*>(this), std::memory_order::acq_rel, std::memory_order::acquire))
            {
                // We've successfully added ourself to the waiter queue.
                return true;
            }
        }
    } while (true);
}

} // namespace detail

scoped_lock::~scoped_lock()
{
    unlock();
}

auto scoped_lock::unlock() -> void
{
    if (m_mutex != nullptr)
    {
        std::atomic_thread_fence(std::memory_order::acq_rel);
        m_mutex->unlock();
        m_mutex = nullptr;
    }
}

auto mutex::try_lock() -> bool
{
    void* expected = const_cast<void*>(unlocked_value());
    return m_state.compare_exchange_strong(expected, nullptr, std::memory_order::acq_rel, std::memory_order::relaxed);
}

auto mutex::unlock() -> void
{
    void* current = m_state.load(std::memory_order::acquire);
    do
    {
        // Sanity check that the mutex isn't already unlocked.
        if (current == const_cast<void*>(unlocked_value()))
        {
            throw std::runtime_error{"coro::mutex is already unlocked"};
        }

        // There are no current waiters, attempt to set the mutex as unlocked.
        if (current == nullptr)
        {
            if (m_state.compare_exchange_weak(
                current,
                const_cast<void*>(unlocked_value()),
                std::memory_order::acq_rel,
                std::memory_order::acquire))
            {
                // We've successfully unlocked the mutex, return since there are no current waiters.
                std::atomic_thread_fence(std::memory_order::acq_rel);
                return;
            }
            else
            {
                // This means someone has added themselves as a waiter, we need to try again with our updated current state.
                // assert(m_state now holds a lock_operation_base*)
                continue;
            }
        }
        else
        {
            // There are waiters, lets wake the first one up. This will set the state to the next waiter, or nullptr (no waiters but locked).
            std::atomic<detail::lock_operation_base*>* casted = reinterpret_cast<std::atomic<detail::lock_operation_base*>*>(&m_state);
            auto* waiter = detail::awaiter_list_pop<detail::lock_operation_base>(*casted);
            // assert waiter != nullptr, nobody else should be unlocking this mutex.
            // Directly transfer control to the waiter, they are now responsible for unlocking the mutex.
            std::atomic_thread_fence(std::memory_order::acq_rel);
            waiter->m_awaiting_coroutine.resume();
            return;
        }
    } while (true);
}

} // namespace coro

1	#include "coro/detail/awaiter_list.hpp"
2	#include "coro/mutex.hpp"
3
4	namespace coro
5	{
6	namespace detail
7	{
8	auto lock_operation_base::await_ready() const noexcept -> bool	49,183,859✔
9	{
10	return m_mutex.try_lock();	49,183,859✔
11	}
12
13	auto lock_operation_base::await_suspend(std::coroutine_handle<> awaiting_coroutine) noexcept -> bool	2,540,722✔
14	{
15	m_awaiting_coroutine = awaiting_coroutine;	2,540,722✔
16	auto& state = m_mutex.m_state;	2,540,722✔
17	void* current = state.load(std::memory_order::acquire);	2,540,722✔
18	const void* unlocked_value = m_mutex.unlocked_value();	2,564,009✔
19	do
20	{
21	// While trying to suspend the lock can become available, if so attempt to grab it and then don't suspend.
22	// If the lock never becomes available then we place ourself at the head of the waiter list and suspend.
23
24	if (current == unlocked_value)	3,258,975✔
25	{
26	// The lock has become available, try and lock.
27	if (state.compare_exchange_weak(current, nullptr, std::memory_order::acq_rel, std::memory_order::acquire))	475,905✔
28	{
29	// We've acquired the lock, don't suspend.
30	m_awaiting_coroutine = nullptr;	343,974✔
31	return false;	425,806✔
32	}
33	}
34	else // if (current == nullptr \|\| current is of type lock_operation_base*)
35	{
36	// The lock is still owned, attempt to add ourself as a waiter.
37	m_next = static_cast<lock_operation_base*>(current);	2,783,070✔
38	if (state.compare_exchange_weak(current, static_cast<void*>(this), std::memory_order::acq_rel, std::memory_order::acquire))	2,783,070✔
39	{
40	// We've successfully added ourself to the waiter queue.
41	return true;	2,218,219✔
42	}
43	}
44	} while (true);
45	}
46
47	} // namespace detail
48
49	scoped_lock::~scoped_lock()	27,425,287✔
50	{
51	unlock();	27,425,287✔
52	}	27,435,379✔
53
54	auto scoped_lock::unlock() -> void	32,861,130✔
55	{
56	if (m_mutex != nullptr)	32,861,130✔
57	{
58	std::atomic_thread_fence(std::memory_order::acq_rel);
59	m_mutex->unlock();	27,445,909✔
60	m_mutex = nullptr;	27,436,360✔
61	}
62	}	32,851,581✔
63
64	auto mutex::try_lock() -> bool	49,178,854✔
65	{
66	void* expected = const_cast<void*>(unlocked_value());	49,178,854✔
67	return m_state.compare_exchange_strong(expected, nullptr, std::memory_order::acq_rel, std::memory_order::relaxed);	49,205,742✔
68	}
69
70	auto mutex::unlock() -> void	49,446,322✔
71	{
72	void* current = m_state.load(std::memory_order::acquire);	49,446,322✔
73	do
74	{
75	// Sanity check that the mutex isn't already unlocked.
76	if (current == const_cast<void*>(unlocked_value()))	49,703,296✔
77	{
NEW 78	throw std::runtime_error{"coro::mutex is already unlocked"};	×
79	}
80
81	// There are no current waiters, attempt to set the mutex as unlocked.
82	if (current == nullptr)	49,703,296✔
83	{
84	if (m_state.compare_exchange_weak(	47,481,817✔
85	current,
86	const_cast<void*>(unlocked_value()),	47,481,817✔
87	std::memory_order::acq_rel,
88	std::memory_order::acquire))
89	{
90	// We've successfully unlocked the mutex, return since there are no current waiters.
91	std::atomic_thread_fence(std::memory_order::acq_rel);
92	return;	47,224,842✔
93	}
94	else
95	{
96	// This means someone has added themselves as a waiter, we need to try again with our updated current state.
97	// assert(m_state now holds a lock_operation_base*)
98	continue;	256,974✔
99	}
100	}
101	else
102	{
103	// There are waiters, lets wake the first one up. This will set the state to the next waiter, or nullptr (no waiters but locked).
104	std::atomic<detail::lock_operation_base> casted = reinterpret_cast<std::atomic<detail::lock_operation_base>>(&m_state);	2,221,479✔
105	auto* waiter = detail::awaiter_list_pop<detail::lock_operation_base>(*casted);	2,221,479✔
106	// assert waiter != nullptr, nobody else should be unlocking this mutex.
107	// Directly transfer control to the waiter, they are now responsible for unlocking the mutex.
108	std::atomic_thread_fence(std::memory_order::acq_rel);
109	waiter->m_awaiting_coroutine.resume();	2,221,479✔
110	return;	2,210,019✔
111	}
112	} while (true);	256,974✔
113	}
114
115	} // namespace coro

jbaldwin / libcoro / 15456637126

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