1   
//
1   
//
2   
// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
2   
// Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   
//
3   
//
4   
// Distributed under the Boost Software License, Version 1.0. (See accompanying
4   
// Distributed under the Boost Software License, Version 1.0. (See accompanying
5   
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5   
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6   
//
6   
//
7   
// Official repository: https://github.com/cppalliance/capy
7   
// Official repository: https://github.com/cppalliance/capy
8   
//
8   
//
9  
9  
10   
#ifndef BOOST_CAPY_RUN_HPP
10   
#ifndef BOOST_CAPY_RUN_HPP
11   
#define BOOST_CAPY_RUN_HPP
11   
#define BOOST_CAPY_RUN_HPP
12  
12  
13   
#include <boost/capy/detail/config.hpp>
13   
#include <boost/capy/detail/config.hpp>
14   
#include <boost/capy/detail/run.hpp>
14   
#include <boost/capy/detail/run.hpp>
15   
#include <boost/capy/concept/executor.hpp>
15   
#include <boost/capy/concept/executor.hpp>
16   
#include <boost/capy/concept/io_runnable.hpp>
16   
#include <boost/capy/concept/io_runnable.hpp>
17   
#include <boost/capy/ex/executor_ref.hpp>
17   
#include <boost/capy/ex/executor_ref.hpp>
18   
#include <coroutine>
18   
#include <coroutine>
19   
#include <boost/capy/ex/frame_allocator.hpp>
19   
#include <boost/capy/ex/frame_allocator.hpp>
20   
#include <boost/capy/ex/io_env.hpp>
20   
#include <boost/capy/ex/io_env.hpp>
21  
21  
22   
#include <memory_resource>
22   
#include <memory_resource>
23   
#include <stop_token>
23   
#include <stop_token>
24   
#include <type_traits>
24   
#include <type_traits>
25   
#include <utility>
25   
#include <utility>
26   
#include <variant>
26   
#include <variant>
27  
27  
28   
/*
28   
/*
29   
    Allocator Lifetime Strategy
29   
    Allocator Lifetime Strategy
30   
    ===========================
30   
    ===========================
31  
31  
32   
    When using run() with a custom allocator:
32   
    When using run() with a custom allocator:
33  
33  
34   
        co_await run(ex, alloc)(my_task());
34   
        co_await run(ex, alloc)(my_task());
35  
35  
36   
    The evaluation order is:
36   
    The evaluation order is:
37   
        1. run(ex, alloc) creates a temporary wrapper
37   
        1. run(ex, alloc) creates a temporary wrapper
38   
        2. my_task() allocates its coroutine frame using TLS
38   
        2. my_task() allocates its coroutine frame using TLS
39   
        3. operator() returns an awaitable
39   
        3. operator() returns an awaitable
40   
        4. Wrapper temporary is DESTROYED
40   
        4. Wrapper temporary is DESTROYED
41   
        5. co_await suspends caller, resumes task
41   
        5. co_await suspends caller, resumes task
42   
        6. Task body executes (wrapper is already dead!)
42   
        6. Task body executes (wrapper is already dead!)
43  
43  
44   
    Problem: The wrapper's frame_memory_resource dies before the task
44   
    Problem: The wrapper's frame_memory_resource dies before the task
45   
    body runs. When initial_suspend::await_resume() restores TLS from
45   
    body runs. When initial_suspend::await_resume() restores TLS from
46   
    the saved pointer, it would point to dead memory.
46   
    the saved pointer, it would point to dead memory.
47  
47  
48   
    Solution: Store a COPY of the allocator in the awaitable (not just
48   
    Solution: Store a COPY of the allocator in the awaitable (not just
49   
    the wrapper). The co_await mechanism extends the awaitable's lifetime
49   
    the wrapper). The co_await mechanism extends the awaitable's lifetime
50   
    until the await completes. In await_suspend, we overwrite the promise's
50   
    until the await completes. In await_suspend, we overwrite the promise's
51   
    saved frame_allocator pointer to point to the awaitable's resource.
51   
    saved frame_allocator pointer to point to the awaitable's resource.
52  
52  
53   
    This works because standard allocator copies are equivalent - memory
53   
    This works because standard allocator copies are equivalent - memory
54   
    allocated with one copy can be deallocated with another copy. The
54   
    allocated with one copy can be deallocated with another copy. The
55   
    task's own frame uses the footer-stored pointer (safe), while nested
55   
    task's own frame uses the footer-stored pointer (safe), while nested
56   
    task creation uses TLS pointing to the awaitable's resource (also safe).
56   
    task creation uses TLS pointing to the awaitable's resource (also safe).
57   
*/
57   
*/
58  
58  
59   
namespace boost::capy::detail {
59   
namespace boost::capy::detail {
60  
60  
61   
//----------------------------------------------------------
61   
//----------------------------------------------------------
62   
//
62   
//
63   
// dispatch_trampoline - cross-executor dispatch
63   
// dispatch_trampoline - cross-executor dispatch
64   
//
64   
//
65   
//----------------------------------------------------------
65   
//----------------------------------------------------------
66  
66  
67   
/** Minimal coroutine that dispatches through the caller's executor.
67   
/** Minimal coroutine that dispatches through the caller's executor.
68  
68  
69   
    Sits between the inner task and the parent when executors
69   
    Sits between the inner task and the parent when executors
70   
    diverge. The inner task's `final_suspend` resumes this
70   
    diverge. The inner task's `final_suspend` resumes this
71   
    trampoline via symmetric transfer. The trampoline's own
71   
    trampoline via symmetric transfer. The trampoline's own
72   
    `final_suspend` dispatches the parent through the caller's
72   
    `final_suspend` dispatches the parent through the caller's
73   
    executor to restore the correct execution context.
73   
    executor to restore the correct execution context.
74  
74  
75   
    The trampoline never touches the task's result.
75   
    The trampoline never touches the task's result.
76   
*/
76   
*/
77   
struct dispatch_trampoline
77   
struct dispatch_trampoline
78   
{
78   
{
79   
    struct promise_type
79   
    struct promise_type
80   
    {
80   
    {
81   
        executor_ref caller_ex_;
81   
        executor_ref caller_ex_;
82   
        std::coroutine_handle<> parent_;
82   
        std::coroutine_handle<> parent_;
83  
83  
84   
        dispatch_trampoline get_return_object() noexcept
84   
        dispatch_trampoline get_return_object() noexcept
85   
        {
85   
        {
86   
            return dispatch_trampoline{
86   
            return dispatch_trampoline{
87   
                std::coroutine_handle<promise_type>::from_promise(*this)};
87   
                std::coroutine_handle<promise_type>::from_promise(*this)};
88   
        }
88   
        }
89  
89  
90   
        std::suspend_always initial_suspend() noexcept { return {}; }
90   
        std::suspend_always initial_suspend() noexcept { return {}; }
91  
91  
92   
        auto final_suspend() noexcept
92   
        auto final_suspend() noexcept
93   
        {
93   
        {
94   
            struct awaiter
94   
            struct awaiter
95   
            {
95   
            {
96   
                promise_type* p_;
96   
                promise_type* p_;
97   
                bool await_ready() const noexcept { return false; }
97   
                bool await_ready() const noexcept { return false; }
98  
98  
99   
                std::coroutine_handle<> await_suspend(
99   
                std::coroutine_handle<> await_suspend(
100   
                    std::coroutine_handle<>) noexcept
100   
                    std::coroutine_handle<>) noexcept
101   
                {
101   
                {
102   
                    return p_->caller_ex_.dispatch(p_->parent_);
102   
                    return p_->caller_ex_.dispatch(p_->parent_);
103   
                }
103   
                }
104  
104  
105   
                void await_resume() const noexcept {}
105   
                void await_resume() const noexcept {}
106   
            };
106   
            };
107   
            return awaiter{this};
107   
            return awaiter{this};
108   
        }
108   
        }
109  
109  
110   
        void return_void() noexcept {}
110   
        void return_void() noexcept {}
111   
        void unhandled_exception() noexcept {}
111   
        void unhandled_exception() noexcept {}
112   
    };
112   
    };
113  
113  
114   
    std::coroutine_handle<promise_type> h_{nullptr};
114   
    std::coroutine_handle<promise_type> h_{nullptr};
115  
115  
116   
    dispatch_trampoline() noexcept = default;
116   
    dispatch_trampoline() noexcept = default;
117  
117  
118   
    ~dispatch_trampoline()
118   
    ~dispatch_trampoline()
119   
    {
119   
    {
120   
        if(h_) h_.destroy();
120   
        if(h_) h_.destroy();
121   
    }
121   
    }
122  
122  
123   
    dispatch_trampoline(dispatch_trampoline const&) = delete;
123   
    dispatch_trampoline(dispatch_trampoline const&) = delete;
124   
    dispatch_trampoline& operator=(dispatch_trampoline const&) = delete;
124   
    dispatch_trampoline& operator=(dispatch_trampoline const&) = delete;
125  
125  
126   
    dispatch_trampoline(dispatch_trampoline&& o) noexcept
126   
    dispatch_trampoline(dispatch_trampoline&& o) noexcept
127   
        : h_(std::exchange(o.h_, nullptr)) {}
127   
        : h_(std::exchange(o.h_, nullptr)) {}
128  
128  
129   
    dispatch_trampoline& operator=(dispatch_trampoline&& o) noexcept
129   
    dispatch_trampoline& operator=(dispatch_trampoline&& o) noexcept
130   
    {
130   
    {
131   
        if(this != &o)
131   
        if(this != &o)
132   
        {
132   
        {
133   
            if(h_) h_.destroy();
133   
            if(h_) h_.destroy();
134   
            h_ = std::exchange(o.h_, nullptr);
134   
            h_ = std::exchange(o.h_, nullptr);
135   
        }
135   
        }
136   
        return *this;
136   
        return *this;
137   
    }
137   
    }
138  
138  
139   
private:
139   
private:
140   
    explicit dispatch_trampoline(std::coroutine_handle<promise_type> h) noexcept
140   
    explicit dispatch_trampoline(std::coroutine_handle<promise_type> h) noexcept
141   
        : h_(h) {}
141   
        : h_(h) {}
142   
};
142   
};
143  
143  
144   
inline dispatch_trampoline make_dispatch_trampoline()
144   
inline dispatch_trampoline make_dispatch_trampoline()
145   
{
145   
{
146   
    co_return;
146   
    co_return;
147   
}
147   
}
148  
148  
149   
//----------------------------------------------------------
149   
//----------------------------------------------------------
150   
//
150   
//
151   
// run_awaitable_ex - with executor (executor switch)
151   
// run_awaitable_ex - with executor (executor switch)
152   
//
152   
//
153   
//----------------------------------------------------------
153   
//----------------------------------------------------------
154  
154  
155   
/** Awaitable that binds an IoRunnable to a specific executor.
155   
/** Awaitable that binds an IoRunnable to a specific executor.
156  
156  
157   
    Stores the executor and inner task by value. When co_awaited, the
157   
    Stores the executor and inner task by value. When co_awaited, the
158   
    co_await expression's lifetime extension keeps both alive for the
158   
    co_await expression's lifetime extension keeps both alive for the
159   
    duration of the operation.
159   
    duration of the operation.
160  
160  
161   
    A dispatch trampoline handles the executor switch on completion:
161   
    A dispatch trampoline handles the executor switch on completion:
162   
    the inner task's `final_suspend` resumes the trampoline, which
162   
    the inner task's `final_suspend` resumes the trampoline, which
163   
    dispatches back through the caller's executor.
163   
    dispatches back through the caller's executor.
164  
164  
165   
    The `io_env` is owned by this awaitable and is guaranteed to
165   
    The `io_env` is owned by this awaitable and is guaranteed to
166   
    outlive the inner task and all awaitables in its chain. Awaitables
166   
    outlive the inner task and all awaitables in its chain. Awaitables
167   
    may store `io_env const*` without concern for dangling references.
167   
    may store `io_env const*` without concern for dangling references.
168  
168  
169   
    @tparam Task The IoRunnable type
169   
    @tparam Task The IoRunnable type
170   
    @tparam Ex The executor type
170   
    @tparam Ex The executor type
171   
    @tparam InheritStopToken If true, inherit caller's stop token
171   
    @tparam InheritStopToken If true, inherit caller's stop token
172   
    @tparam Alloc The allocator type (void for no allocator)
172   
    @tparam Alloc The allocator type (void for no allocator)
173   
*/
173   
*/
174   
template<IoRunnable Task, Executor Ex, bool InheritStopToken, class Alloc = void>
174   
template<IoRunnable Task, Executor Ex, bool InheritStopToken, class Alloc = void>
175   
struct [[nodiscard]] run_awaitable_ex
175   
struct [[nodiscard]] run_awaitable_ex
176   
{
176   
{
177   
    Ex ex_;
177   
    Ex ex_;
178   
    frame_memory_resource<Alloc> resource_;
178   
    frame_memory_resource<Alloc> resource_;
179   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
179   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
180   
    io_env env_;
180   
    io_env env_;
181   
    dispatch_trampoline tr_;
181   
    dispatch_trampoline tr_;
182   
    Task inner_;  // Last: destroyed first, while env_ is still valid
182   
    Task inner_;  // Last: destroyed first, while env_ is still valid
183  
183  
184   
    // void allocator, inherit stop token
184   
    // void allocator, inherit stop token
185   
    run_awaitable_ex(Ex ex, Task inner)
185   
    run_awaitable_ex(Ex ex, Task inner)
186   
        requires (InheritStopToken && std::is_void_v<Alloc>)
186   
        requires (InheritStopToken && std::is_void_v<Alloc>)
187   
        : ex_(std::move(ex))
187   
        : ex_(std::move(ex))
188   
        , inner_(std::move(inner))
188   
        , inner_(std::move(inner))
189   
    {
189   
    {
190   
    }
190   
    }
191  
191  
192   
    // void allocator, explicit stop token
192   
    // void allocator, explicit stop token
193   
    run_awaitable_ex(Ex ex, Task inner, std::stop_token st)
193   
    run_awaitable_ex(Ex ex, Task inner, std::stop_token st)
194   
        requires (!InheritStopToken && std::is_void_v<Alloc>)
194   
        requires (!InheritStopToken && std::is_void_v<Alloc>)
195   
        : ex_(std::move(ex))
195   
        : ex_(std::move(ex))
196   
        , st_(std::move(st))
196   
        , st_(std::move(st))
197   
        , inner_(std::move(inner))
197   
        , inner_(std::move(inner))
198   
    {
198   
    {
199   
    }
199   
    }
200  
200  
201   
    // with allocator, inherit stop token (use template to avoid void parameter)
201   
    // with allocator, inherit stop token (use template to avoid void parameter)
202   
    template<class A>
202   
    template<class A>
203   
        requires (InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
203   
        requires (InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
204   
    run_awaitable_ex(Ex ex, A alloc, Task inner)
204   
    run_awaitable_ex(Ex ex, A alloc, Task inner)
205   
        : ex_(std::move(ex))
205   
        : ex_(std::move(ex))
206   
        , resource_(std::move(alloc))
206   
        , resource_(std::move(alloc))
207   
        , inner_(std::move(inner))
207   
        , inner_(std::move(inner))
208   
    {
208   
    {
209   
    }
209   
    }
210  
210  
211   
    // with allocator, explicit stop token (use template to avoid void parameter)
211   
    // with allocator, explicit stop token (use template to avoid void parameter)
212   
    template<class A>
212   
    template<class A>
213   
        requires (!InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
213   
        requires (!InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
214   
    run_awaitable_ex(Ex ex, A alloc, Task inner, std::stop_token st)
214   
    run_awaitable_ex(Ex ex, A alloc, Task inner, std::stop_token st)
215   
        : ex_(std::move(ex))
215   
        : ex_(std::move(ex))
216   
        , resource_(std::move(alloc))
216   
        , resource_(std::move(alloc))
217   
        , st_(std::move(st))
217   
        , st_(std::move(st))
218   
        , inner_(std::move(inner))
218   
        , inner_(std::move(inner))
219   
    {
219   
    {
220   
    }
220   
    }
221  
221  
222   
    bool await_ready() const noexcept
222   
    bool await_ready() const noexcept
223   
    {
223   
    {
224   
        return inner_.await_ready();
224   
        return inner_.await_ready();
225   
    }
225   
    }
226  
226  
227   
    decltype(auto) await_resume()
227   
    decltype(auto) await_resume()
228   
    {
228   
    {
229   
        return inner_.await_resume();
229   
        return inner_.await_resume();
230   
    }
230   
    }
231  
231  
232   
    std::coroutine_handle<> await_suspend(std::coroutine_handle<> cont, io_env const* caller_env)
232   
    std::coroutine_handle<> await_suspend(std::coroutine_handle<> cont, io_env const* caller_env)
233   
    {
233   
    {
234   
        tr_ = make_dispatch_trampoline();
234   
        tr_ = make_dispatch_trampoline();
235   
        tr_.h_.promise().caller_ex_ = caller_env->executor;
235   
        tr_.h_.promise().caller_ex_ = caller_env->executor;
236   
        tr_.h_.promise().parent_ = cont;
236   
        tr_.h_.promise().parent_ = cont;
237  
237  
238   
        auto h = inner_.handle();
238   
        auto h = inner_.handle();
239   
        auto& p = h.promise();
239   
        auto& p = h.promise();
240   
        p.set_continuation(tr_.h_);
240   
        p.set_continuation(tr_.h_);
241  
241  
242   
        env_.executor = ex_;
242   
        env_.executor = ex_;
243   
        if constexpr (InheritStopToken)
243   
        if constexpr (InheritStopToken)
244   
            env_.stop_token = caller_env->stop_token;
244   
            env_.stop_token = caller_env->stop_token;
245   
        else
245   
        else
246   
            env_.stop_token = st_;
246   
            env_.stop_token = st_;
247  
247  
248   
        if constexpr (!std::is_void_v<Alloc>)
248   
        if constexpr (!std::is_void_v<Alloc>)
249   
            env_.allocator = resource_.get();
249   
            env_.allocator = resource_.get();
250   
        else
250   
        else
251   
            env_.allocator = caller_env->allocator;
251   
            env_.allocator = caller_env->allocator;
252  
252  
253   
        p.set_environment(&env_);
253   
        p.set_environment(&env_);
254   
        return h;
254   
        return h;
255   
    }
255   
    }
256  
256  
257   
    // Non-copyable
257   
    // Non-copyable
258   
    run_awaitable_ex(run_awaitable_ex const&) = delete;
258   
    run_awaitable_ex(run_awaitable_ex const&) = delete;
259   
    run_awaitable_ex& operator=(run_awaitable_ex const&) = delete;
259   
    run_awaitable_ex& operator=(run_awaitable_ex const&) = delete;
260  
260  
261   
    // Movable (no noexcept - Task may throw)
261   
    // Movable (no noexcept - Task may throw)
262   
    run_awaitable_ex(run_awaitable_ex&&) = default;
262   
    run_awaitable_ex(run_awaitable_ex&&) = default;
263   
    run_awaitable_ex& operator=(run_awaitable_ex&&) = default;
263   
    run_awaitable_ex& operator=(run_awaitable_ex&&) = default;
264   
};
264   
};
265  
265  
266   
//----------------------------------------------------------
266   
//----------------------------------------------------------
267   
//
267   
//
268   
// run_awaitable - no executor (inherits caller's executor)
268   
// run_awaitable - no executor (inherits caller's executor)
269   
//
269   
//
270   
//----------------------------------------------------------
270   
//----------------------------------------------------------
271  
271  
272   
/** Awaitable that runs a task with optional stop_token override.
272   
/** Awaitable that runs a task with optional stop_token override.
273  
273  
274   
    Does NOT store an executor - the task inherits the caller's executor
274   
    Does NOT store an executor - the task inherits the caller's executor
275   
    directly. Executors always match, so no dispatch trampoline is needed.
275   
    directly. Executors always match, so no dispatch trampoline is needed.
276   
    The inner task's `final_suspend` resumes the parent directly via
276   
    The inner task's `final_suspend` resumes the parent directly via
277   
    unconditional symmetric transfer.
277   
    unconditional symmetric transfer.
278  
278  
279   
    @tparam Task The IoRunnable type
279   
    @tparam Task The IoRunnable type
280   
    @tparam InheritStopToken If true, inherit caller's stop token
280   
    @tparam InheritStopToken If true, inherit caller's stop token
281   
    @tparam Alloc The allocator type (void for no allocator)
281   
    @tparam Alloc The allocator type (void for no allocator)
282   
*/
282   
*/
283   
template<IoRunnable Task, bool InheritStopToken, class Alloc = void>
283   
template<IoRunnable Task, bool InheritStopToken, class Alloc = void>
284   
struct [[nodiscard]] run_awaitable
284   
struct [[nodiscard]] run_awaitable
285   
{
285   
{
286   
    frame_memory_resource<Alloc> resource_;
286   
    frame_memory_resource<Alloc> resource_;
287   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
287   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
288   
    io_env env_;
288   
    io_env env_;
289   
    Task inner_;  // Last: destroyed first, while env_ is still valid
289   
    Task inner_;  // Last: destroyed first, while env_ is still valid
290  
290  
291   
    // void allocator, inherit stop token
291   
    // void allocator, inherit stop token
292   
    explicit run_awaitable(Task inner)
292   
    explicit run_awaitable(Task inner)
293   
        requires (InheritStopToken && std::is_void_v<Alloc>)
293   
        requires (InheritStopToken && std::is_void_v<Alloc>)
294   
        : inner_(std::move(inner))
294   
        : inner_(std::move(inner))
295   
    {
295   
    {
296   
    }
296   
    }
297  
297  
298   
    // void allocator, explicit stop token
298   
    // void allocator, explicit stop token
299   
    run_awaitable(Task inner, std::stop_token st)
299   
    run_awaitable(Task inner, std::stop_token st)
300   
        requires (!InheritStopToken && std::is_void_v<Alloc>)
300   
        requires (!InheritStopToken && std::is_void_v<Alloc>)
301   
        : st_(std::move(st))
301   
        : st_(std::move(st))
302   
        , inner_(std::move(inner))
302   
        , inner_(std::move(inner))
303   
    {
303   
    {
304   
    }
304   
    }
305  
305  
306   
    // with allocator, inherit stop token (use template to avoid void parameter)
306   
    // with allocator, inherit stop token (use template to avoid void parameter)
307   
    template<class A>
307   
    template<class A>
308   
        requires (InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
308   
        requires (InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
309   
    run_awaitable(A alloc, Task inner)
309   
    run_awaitable(A alloc, Task inner)
310   
        : resource_(std::move(alloc))
310   
        : resource_(std::move(alloc))
311   
        , inner_(std::move(inner))
311   
        , inner_(std::move(inner))
312   
    {
312   
    {
313   
    }
313   
    }
314  
314  
315   
    // with allocator, explicit stop token (use template to avoid void parameter)
315   
    // with allocator, explicit stop token (use template to avoid void parameter)
316   
    template<class A>
316   
    template<class A>
317   
        requires (!InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
317   
        requires (!InheritStopToken && !std::is_void_v<Alloc> && std::same_as<A, Alloc>)
318   
    run_awaitable(A alloc, Task inner, std::stop_token st)
318   
    run_awaitable(A alloc, Task inner, std::stop_token st)
319   
        : resource_(std::move(alloc))
319   
        : resource_(std::move(alloc))
320   
        , st_(std::move(st))
320   
        , st_(std::move(st))
321   
        , inner_(std::move(inner))
321   
        , inner_(std::move(inner))
322   
    {
322   
    {
323   
    }
323   
    }
324  
324  
325   
    bool await_ready() const noexcept
325   
    bool await_ready() const noexcept
326   
    {
326   
    {
327   
        return inner_.await_ready();
327   
        return inner_.await_ready();
328   
    }
328   
    }
329  
329  
330   
    decltype(auto) await_resume()
330   
    decltype(auto) await_resume()
331   
    {
331   
    {
332   
        return inner_.await_resume();
332   
        return inner_.await_resume();
333   
    }
333   
    }
334  
334  
335   
    std::coroutine_handle<> await_suspend(std::coroutine_handle<> cont, io_env const* caller_env)
335   
    std::coroutine_handle<> await_suspend(std::coroutine_handle<> cont, io_env const* caller_env)
336   
    {
336   
    {
337   
        auto h = inner_.handle();
337   
        auto h = inner_.handle();
338   
        auto& p = h.promise();
338   
        auto& p = h.promise();
339   
        p.set_continuation(cont);
339   
        p.set_continuation(cont);
340  
340  
341   
        env_.executor = caller_env->executor;
341   
        env_.executor = caller_env->executor;
342   
        if constexpr (InheritStopToken)
342   
        if constexpr (InheritStopToken)
343   
            env_.stop_token = caller_env->stop_token;
343   
            env_.stop_token = caller_env->stop_token;
344   
        else
344   
        else
345   
            env_.stop_token = st_;
345   
            env_.stop_token = st_;
346  
346  
347   
        if constexpr (!std::is_void_v<Alloc>)
347   
        if constexpr (!std::is_void_v<Alloc>)
348   
            env_.allocator = resource_.get();
348   
            env_.allocator = resource_.get();
349   
        else
349   
        else
350   
            env_.allocator = caller_env->allocator;
350   
            env_.allocator = caller_env->allocator;
351  
351  
352   
        p.set_environment(&env_);
352   
        p.set_environment(&env_);
353   
        return h;
353   
        return h;
354   
    }
354   
    }
355  
355  
356   
    // Non-copyable
356   
    // Non-copyable
357   
    run_awaitable(run_awaitable const&) = delete;
357   
    run_awaitable(run_awaitable const&) = delete;
358   
    run_awaitable& operator=(run_awaitable const&) = delete;
358   
    run_awaitable& operator=(run_awaitable const&) = delete;
359  
359  
360   
    // Movable (no noexcept - Task may throw)
360   
    // Movable (no noexcept - Task may throw)
361   
    run_awaitable(run_awaitable&&) = default;
361   
    run_awaitable(run_awaitable&&) = default;
362   
    run_awaitable& operator=(run_awaitable&&) = default;
362   
    run_awaitable& operator=(run_awaitable&&) = default;
363   
};
363   
};
364  
364  
365   
//----------------------------------------------------------
365   
//----------------------------------------------------------
366   
//
366   
//
367   
// run_wrapper_ex - with executor
367   
// run_wrapper_ex - with executor
368   
//
368   
//
369   
//----------------------------------------------------------
369   
//----------------------------------------------------------
370  
370  
371   
/** Wrapper returned by run(ex, ...) that accepts a task for execution.
371   
/** Wrapper returned by run(ex, ...) that accepts a task for execution.
372  
372  
373   
    @tparam Ex The executor type.
373   
    @tparam Ex The executor type.
374   
    @tparam InheritStopToken If true, inherit caller's stop token.
374   
    @tparam InheritStopToken If true, inherit caller's stop token.
375   
    @tparam Alloc The allocator type (void for no allocator).
375   
    @tparam Alloc The allocator type (void for no allocator).
376   
*/
376   
*/
377   
template<Executor Ex, bool InheritStopToken, class Alloc>
377   
template<Executor Ex, bool InheritStopToken, class Alloc>
378   
class [[nodiscard]] run_wrapper_ex
378   
class [[nodiscard]] run_wrapper_ex
379   
{
379   
{
380   
    Ex ex_;
380   
    Ex ex_;
381   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
381   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
382   
    frame_memory_resource<Alloc> resource_;
382   
    frame_memory_resource<Alloc> resource_;
383   
    Alloc alloc_;  // Copy to pass to awaitable
383   
    Alloc alloc_;  // Copy to pass to awaitable
384  
384  
385   
public:
385   
public:
386   
    run_wrapper_ex(Ex ex, Alloc alloc)
386   
    run_wrapper_ex(Ex ex, Alloc alloc)
387   
        requires InheritStopToken
387   
        requires InheritStopToken
388   
        : ex_(std::move(ex))
388   
        : ex_(std::move(ex))
389   
        , resource_(alloc)
389   
        , resource_(alloc)
390   
        , alloc_(std::move(alloc))
390   
        , alloc_(std::move(alloc))
391   
    {
391   
    {
392   
        current_frame_allocator() = &resource_;
392   
        current_frame_allocator() = &resource_;
393   
    }
393   
    }
394  
394  
395   
    run_wrapper_ex(Ex ex, std::stop_token st, Alloc alloc)
395   
    run_wrapper_ex(Ex ex, std::stop_token st, Alloc alloc)
396   
        requires (!InheritStopToken)
396   
        requires (!InheritStopToken)
397   
        : ex_(std::move(ex))
397   
        : ex_(std::move(ex))
398   
        , st_(std::move(st))
398   
        , st_(std::move(st))
399   
        , resource_(alloc)
399   
        , resource_(alloc)
400   
        , alloc_(std::move(alloc))
400   
        , alloc_(std::move(alloc))
401   
    {
401   
    {
402   
        current_frame_allocator() = &resource_;
402   
        current_frame_allocator() = &resource_;
403   
    }
403   
    }
404  
404  
405   
    // Non-copyable, non-movable (must be used immediately)
405   
    // Non-copyable, non-movable (must be used immediately)
406   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
406   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
407   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
407   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
408   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
408   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
409   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
409   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
410  
410  
411   
    template<IoRunnable Task>
411   
    template<IoRunnable Task>
412   
    [[nodiscard]] auto operator()(Task t) &&
412   
    [[nodiscard]] auto operator()(Task t) &&
413   
    {
413   
    {
414   
        if constexpr (InheritStopToken)
414   
        if constexpr (InheritStopToken)
415   
            return run_awaitable_ex<Task, Ex, true, Alloc>{
415   
            return run_awaitable_ex<Task, Ex, true, Alloc>{
416   
                std::move(ex_), std::move(alloc_), std::move(t)};
416   
                std::move(ex_), std::move(alloc_), std::move(t)};
417   
        else
417   
        else
418   
            return run_awaitable_ex<Task, Ex, false, Alloc>{
418   
            return run_awaitable_ex<Task, Ex, false, Alloc>{
419   
                std::move(ex_), std::move(alloc_), std::move(t), std::move(st_)};
419   
                std::move(ex_), std::move(alloc_), std::move(t), std::move(st_)};
420   
    }
420   
    }
421   
};
421   
};
422  
422  
423   
/// Specialization for memory_resource* - stores pointer directly.
423   
/// Specialization for memory_resource* - stores pointer directly.
424   
template<Executor Ex, bool InheritStopToken>
424   
template<Executor Ex, bool InheritStopToken>
425   
class [[nodiscard]] run_wrapper_ex<Ex, InheritStopToken, std::pmr::memory_resource*>
425   
class [[nodiscard]] run_wrapper_ex<Ex, InheritStopToken, std::pmr::memory_resource*>
426   
{
426   
{
427   
    Ex ex_;
427   
    Ex ex_;
428   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
428   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
429   
    std::pmr::memory_resource* mr_;
429   
    std::pmr::memory_resource* mr_;
430  
430  
431   
public:
431   
public:
432   
    run_wrapper_ex(Ex ex, std::pmr::memory_resource* mr)
432   
    run_wrapper_ex(Ex ex, std::pmr::memory_resource* mr)
433   
        requires InheritStopToken
433   
        requires InheritStopToken
434   
        : ex_(std::move(ex))
434   
        : ex_(std::move(ex))
435   
        , mr_(mr)
435   
        , mr_(mr)
436   
    {
436   
    {
437   
        current_frame_allocator() = mr_;
437   
        current_frame_allocator() = mr_;
438   
    }
438   
    }
439  
439  
440   
    run_wrapper_ex(Ex ex, std::stop_token st, std::pmr::memory_resource* mr)
440   
    run_wrapper_ex(Ex ex, std::stop_token st, std::pmr::memory_resource* mr)
441   
        requires (!InheritStopToken)
441   
        requires (!InheritStopToken)
442   
        : ex_(std::move(ex))
442   
        : ex_(std::move(ex))
443   
        , st_(std::move(st))
443   
        , st_(std::move(st))
444   
        , mr_(mr)
444   
        , mr_(mr)
445   
    {
445   
    {
446   
        current_frame_allocator() = mr_;
446   
        current_frame_allocator() = mr_;
447   
    }
447   
    }
448  
448  
449   
    // Non-copyable, non-movable (must be used immediately)
449   
    // Non-copyable, non-movable (must be used immediately)
450   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
450   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
451   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
451   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
452   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
452   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
453   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
453   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
454  
454  
455   
    template<IoRunnable Task>
455   
    template<IoRunnable Task>
456   
    [[nodiscard]] auto operator()(Task t) &&
456   
    [[nodiscard]] auto operator()(Task t) &&
457   
    {
457   
    {
458   
        if constexpr (InheritStopToken)
458   
        if constexpr (InheritStopToken)
459   
            return run_awaitable_ex<Task, Ex, true, std::pmr::memory_resource*>{
459   
            return run_awaitable_ex<Task, Ex, true, std::pmr::memory_resource*>{
460   
                std::move(ex_), mr_, std::move(t)};
460   
                std::move(ex_), mr_, std::move(t)};
461   
        else
461   
        else
462   
            return run_awaitable_ex<Task, Ex, false, std::pmr::memory_resource*>{
462   
            return run_awaitable_ex<Task, Ex, false, std::pmr::memory_resource*>{
463   
                std::move(ex_), mr_, std::move(t), std::move(st_)};
463   
                std::move(ex_), mr_, std::move(t), std::move(st_)};
464   
    }
464   
    }
465   
};
465   
};
466  
466  
467   
/// Specialization for no allocator (void).
467   
/// Specialization for no allocator (void).
468   
template<Executor Ex, bool InheritStopToken>
468   
template<Executor Ex, bool InheritStopToken>
469   
class [[nodiscard]] run_wrapper_ex<Ex, InheritStopToken, void>
469   
class [[nodiscard]] run_wrapper_ex<Ex, InheritStopToken, void>
470   
{
470   
{
471   
    Ex ex_;
471   
    Ex ex_;
472   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
472   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
473  
473  
474   
public:
474   
public:
475   
    explicit run_wrapper_ex(Ex ex)
475   
    explicit run_wrapper_ex(Ex ex)
476   
        requires InheritStopToken
476   
        requires InheritStopToken
477   
        : ex_(std::move(ex))
477   
        : ex_(std::move(ex))
478   
    {
478   
    {
479   
    }
479   
    }
480  
480  
481   
    run_wrapper_ex(Ex ex, std::stop_token st)
481   
    run_wrapper_ex(Ex ex, std::stop_token st)
482   
        requires (!InheritStopToken)
482   
        requires (!InheritStopToken)
483   
        : ex_(std::move(ex))
483   
        : ex_(std::move(ex))
484   
        , st_(std::move(st))
484   
        , st_(std::move(st))
485   
    {
485   
    {
486   
    }
486   
    }
487  
487  
488   
    // Non-copyable, non-movable (must be used immediately)
488   
    // Non-copyable, non-movable (must be used immediately)
489   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
489   
    run_wrapper_ex(run_wrapper_ex const&) = delete;
490   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
490   
    run_wrapper_ex(run_wrapper_ex&&) = delete;
491   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
491   
    run_wrapper_ex& operator=(run_wrapper_ex const&) = delete;
492   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
492   
    run_wrapper_ex& operator=(run_wrapper_ex&&) = delete;
493  
493  
494   
    template<IoRunnable Task>
494   
    template<IoRunnable Task>
495   
    [[nodiscard]] auto operator()(Task t) &&
495   
    [[nodiscard]] auto operator()(Task t) &&
496   
    {
496   
    {
497   
        if constexpr (InheritStopToken)
497   
        if constexpr (InheritStopToken)
498   
            return run_awaitable_ex<Task, Ex, true>{
498   
            return run_awaitable_ex<Task, Ex, true>{
499   
                std::move(ex_), std::move(t)};
499   
                std::move(ex_), std::move(t)};
500   
        else
500   
        else
501   
            return run_awaitable_ex<Task, Ex, false>{
501   
            return run_awaitable_ex<Task, Ex, false>{
502   
                std::move(ex_), std::move(t), std::move(st_)};
502   
                std::move(ex_), std::move(t), std::move(st_)};
503   
    }
503   
    }
504   
};
504   
};
505  
505  
506   
//----------------------------------------------------------
506   
//----------------------------------------------------------
507   
//
507   
//
508   
// run_wrapper - no executor (inherits caller's executor)
508   
// run_wrapper - no executor (inherits caller's executor)
509   
//
509   
//
510   
//----------------------------------------------------------
510   
//----------------------------------------------------------
511  
511  
512   
/** Wrapper returned by run(st) or run(alloc) that accepts a task.
512   
/** Wrapper returned by run(st) or run(alloc) that accepts a task.
513  
513  
514   
    @tparam InheritStopToken If true, inherit caller's stop token.
514   
    @tparam InheritStopToken If true, inherit caller's stop token.
515   
    @tparam Alloc The allocator type (void for no allocator).
515   
    @tparam Alloc The allocator type (void for no allocator).
516   
*/
516   
*/
517   
template<bool InheritStopToken, class Alloc>
517   
template<bool InheritStopToken, class Alloc>
518   
class [[nodiscard]] run_wrapper
518   
class [[nodiscard]] run_wrapper
519   
{
519   
{
520   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
520   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
521   
    frame_memory_resource<Alloc> resource_;
521   
    frame_memory_resource<Alloc> resource_;
522   
    Alloc alloc_;  // Copy to pass to awaitable
522   
    Alloc alloc_;  // Copy to pass to awaitable
523  
523  
524   
public:
524   
public:
525   
    explicit run_wrapper(Alloc alloc)
525   
    explicit run_wrapper(Alloc alloc)
526   
        requires InheritStopToken
526   
        requires InheritStopToken
527   
        : resource_(alloc)
527   
        : resource_(alloc)
528   
        , alloc_(std::move(alloc))
528   
        , alloc_(std::move(alloc))
529   
    {
529   
    {
530   
        current_frame_allocator() = &resource_;
530   
        current_frame_allocator() = &resource_;
531   
    }
531   
    }
532  
532  
533   
    run_wrapper(std::stop_token st, Alloc alloc)
533   
    run_wrapper(std::stop_token st, Alloc alloc)
534   
        requires (!InheritStopToken)
534   
        requires (!InheritStopToken)
535   
        : st_(std::move(st))
535   
        : st_(std::move(st))
536   
        , resource_(alloc)
536   
        , resource_(alloc)
537   
        , alloc_(std::move(alloc))
537   
        , alloc_(std::move(alloc))
538   
    {
538   
    {
539   
        current_frame_allocator() = &resource_;
539   
        current_frame_allocator() = &resource_;
540   
    }
540   
    }
541  
541  
542   
    // Non-copyable, non-movable (must be used immediately)
542   
    // Non-copyable, non-movable (must be used immediately)
543   
    run_wrapper(run_wrapper const&) = delete;
543   
    run_wrapper(run_wrapper const&) = delete;
544   
    run_wrapper(run_wrapper&&) = delete;
544   
    run_wrapper(run_wrapper&&) = delete;
545   
    run_wrapper& operator=(run_wrapper const&) = delete;
545   
    run_wrapper& operator=(run_wrapper const&) = delete;
546   
    run_wrapper& operator=(run_wrapper&&) = delete;
546   
    run_wrapper& operator=(run_wrapper&&) = delete;
547  
547  
548   
    template<IoRunnable Task>
548   
    template<IoRunnable Task>
549   
    [[nodiscard]] auto operator()(Task t) &&
549   
    [[nodiscard]] auto operator()(Task t) &&
550   
    {
550   
    {
551   
        if constexpr (InheritStopToken)
551   
        if constexpr (InheritStopToken)
552   
            return run_awaitable<Task, true, Alloc>{
552   
            return run_awaitable<Task, true, Alloc>{
553   
                std::move(alloc_), std::move(t)};
553   
                std::move(alloc_), std::move(t)};
554   
        else
554   
        else
555   
            return run_awaitable<Task, false, Alloc>{
555   
            return run_awaitable<Task, false, Alloc>{
556   
                std::move(alloc_), std::move(t), std::move(st_)};
556   
                std::move(alloc_), std::move(t), std::move(st_)};
557   
    }
557   
    }
558   
};
558   
};
559  
559  
560   
/// Specialization for memory_resource* - stores pointer directly.
560   
/// Specialization for memory_resource* - stores pointer directly.
561   
template<bool InheritStopToken>
561   
template<bool InheritStopToken>
562   
class [[nodiscard]] run_wrapper<InheritStopToken, std::pmr::memory_resource*>
562   
class [[nodiscard]] run_wrapper<InheritStopToken, std::pmr::memory_resource*>
563   
{
563   
{
564   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
564   
    std::conditional_t<InheritStopToken, std::monostate, std::stop_token> st_;
565   
    std::pmr::memory_resource* mr_;
565   
    std::pmr::memory_resource* mr_;
566  
566  
567   
public:
567   
public:
568   
    explicit run_wrapper(std::pmr::memory_resource* mr)
568   
    explicit run_wrapper(std::pmr::memory_resource* mr)
569   
        requires InheritStopToken
569   
        requires InheritStopToken
570   
        : mr_(mr)
570   
        : mr_(mr)
571   
    {
571   
    {
572   
        current_frame_allocator() = mr_;
572   
        current_frame_allocator() = mr_;
573   
    }
573   
    }
574  
574  
575   
    run_wrapper(std::stop_token st, std::pmr::memory_resource* mr)
575   
    run_wrapper(std::stop_token st, std::pmr::memory_resource* mr)
576   
        requires (!InheritStopToken)
576   
        requires (!InheritStopToken)
577   
        : st_(std::move(st))
577   
        : st_(std::move(st))
578   
        , mr_(mr)
578   
        , mr_(mr)
579   
    {
579   
    {
580   
        current_frame_allocator() = mr_;
580   
        current_frame_allocator() = mr_;
581   
    }
581   
    }
582  
582  
583   
    // Non-copyable, non-movable (must be used immediately)
583   
    // Non-copyable, non-movable (must be used immediately)
584   
    run_wrapper(run_wrapper const&) = delete;
584   
    run_wrapper(run_wrapper const&) = delete;
585   
    run_wrapper(run_wrapper&&) = delete;
585   
    run_wrapper(run_wrapper&&) = delete;
586   
    run_wrapper& operator=(run_wrapper const&) = delete;
586   
    run_wrapper& operator=(run_wrapper const&) = delete;
587   
    run_wrapper& operator=(run_wrapper&&) = delete;
587   
    run_wrapper& operator=(run_wrapper&&) = delete;
588  
588  
589   
    template<IoRunnable Task>
589   
    template<IoRunnable Task>
590   
    [[nodiscard]] auto operator()(Task t) &&
590   
    [[nodiscard]] auto operator()(Task t) &&
591   
    {
591   
    {
592   
        if constexpr (InheritStopToken)
592   
        if constexpr (InheritStopToken)
593   
            return run_awaitable<Task, true, std::pmr::memory_resource*>{
593   
            return run_awaitable<Task, true, std::pmr::memory_resource*>{
594   
                mr_, std::move(t)};
594   
                mr_, std::move(t)};
595   
        else
595   
        else
596   
            return run_awaitable<Task, false, std::pmr::memory_resource*>{
596   
            return run_awaitable<Task, false, std::pmr::memory_resource*>{
597   
                mr_, std::move(t), std::move(st_)};
597   
                mr_, std::move(t), std::move(st_)};
598   
    }
598   
    }
599   
};
599   
};
600  
600  
601   
/// Specialization for stop_token only (no allocator).
601   
/// Specialization for stop_token only (no allocator).
602   
template<>
602   
template<>
603   
class [[nodiscard]] run_wrapper<false, void>
603   
class [[nodiscard]] run_wrapper<false, void>
604   
{
604   
{
605   
    std::stop_token st_;
605   
    std::stop_token st_;
606  
606  
607   
public:
607   
public:
608   
    explicit run_wrapper(std::stop_token st)
608   
    explicit run_wrapper(std::stop_token st)
609   
        : st_(std::move(st))
609   
        : st_(std::move(st))
610   
    {
610   
    {
611   
    }
611   
    }
612  
612  
613   
    // Non-copyable, non-movable (must be used immediately)
613   
    // Non-copyable, non-movable (must be used immediately)
614   
    run_wrapper(run_wrapper const&) = delete;
614   
    run_wrapper(run_wrapper const&) = delete;
615   
    run_wrapper(run_wrapper&&) = delete;
615   
    run_wrapper(run_wrapper&&) = delete;
616   
    run_wrapper& operator=(run_wrapper const&) = delete;
616   
    run_wrapper& operator=(run_wrapper const&) = delete;
617   
    run_wrapper& operator=(run_wrapper&&) = delete;
617   
    run_wrapper& operator=(run_wrapper&&) = delete;
618  
618  
619   
    template<IoRunnable Task>
619   
    template<IoRunnable Task>
620   
    [[nodiscard]] auto operator()(Task t) &&
620   
    [[nodiscard]] auto operator()(Task t) &&
621   
    {
621   
    {
622   
        return run_awaitable<Task, false, void>{std::move(t), std::move(st_)};
622   
        return run_awaitable<Task, false, void>{std::move(t), std::move(st_)};
623   
    }
623   
    }
624   
};
624   
};
625  
625  
626   
} // namespace boost::capy::detail
626   
} // namespace boost::capy::detail
627  
627  
628   
namespace boost::capy {
628   
namespace boost::capy {
629  
629  
630   
//----------------------------------------------------------
630   
//----------------------------------------------------------
631   
//
631   
//
632   
// run() overloads - with executor
632   
// run() overloads - with executor
633   
//
633   
//
634   
//----------------------------------------------------------
634   
//----------------------------------------------------------
635  
635  
636   
/** Bind a task to execute on a specific executor.
636   
/** Bind a task to execute on a specific executor.
637  
637  
638   
    Returns a wrapper that accepts a task and produces an awaitable.
638   
    Returns a wrapper that accepts a task and produces an awaitable.
639   
    When co_awaited, the task runs on the specified executor.
639   
    When co_awaited, the task runs on the specified executor.
640  
640  
641   
    @par Example
641   
    @par Example
642   
    @code
642   
    @code
643   
    co_await run(other_executor)(my_task());
643   
    co_await run(other_executor)(my_task());
644   
    @endcode
644   
    @endcode
645  
645  
646   
    @param ex The executor on which the task should run.
646   
    @param ex The executor on which the task should run.
647  
647  
648   
    @return A wrapper that accepts a task for execution.
648   
    @return A wrapper that accepts a task for execution.
649  
649  
650   
    @see task
650   
    @see task
651   
    @see executor
651   
    @see executor
652   
*/
652   
*/
653   
template<Executor Ex>
653   
template<Executor Ex>
654   
[[nodiscard]] auto
654   
[[nodiscard]] auto
655   
run(Ex ex)
655   
run(Ex ex)
656   
{
656   
{
657   
    return detail::run_wrapper_ex<Ex, true, void>{std::move(ex)};
657   
    return detail::run_wrapper_ex<Ex, true, void>{std::move(ex)};
658   
}
658   
}
659  
659  
660   
/** Bind a task to an executor with a stop token.
660   
/** Bind a task to an executor with a stop token.
661  
661  
662   
    @param ex The executor on which the task should run.
662   
    @param ex The executor on which the task should run.
663   
    @param st The stop token for cooperative cancellation.
663   
    @param st The stop token for cooperative cancellation.
664  
664  
665   
    @return A wrapper that accepts a task for execution.
665   
    @return A wrapper that accepts a task for execution.
666   
*/
666   
*/
667   
template<Executor Ex>
667   
template<Executor Ex>
668   
[[nodiscard]] auto
668   
[[nodiscard]] auto
669   
run(Ex ex, std::stop_token st)
669   
run(Ex ex, std::stop_token st)
670   
{
670   
{
671   
    return detail::run_wrapper_ex<Ex, false, void>{
671   
    return detail::run_wrapper_ex<Ex, false, void>{
672   
        std::move(ex), std::move(st)};
672   
        std::move(ex), std::move(st)};
673   
}
673   
}
674  
674  
675   
/** Bind a task to an executor with a memory resource.
675   
/** Bind a task to an executor with a memory resource.
676  
676  
677   
    @param ex The executor on which the task should run.
677   
    @param ex The executor on which the task should run.
678   
    @param mr The memory resource for frame allocation.
678   
    @param mr The memory resource for frame allocation.
679  
679  
680   
    @return A wrapper that accepts a task for execution.
680   
    @return A wrapper that accepts a task for execution.
681   
*/
681   
*/
682   
template<Executor Ex>
682   
template<Executor Ex>
683   
[[nodiscard]] auto
683   
[[nodiscard]] auto
684   
run(Ex ex, std::pmr::memory_resource* mr)
684   
run(Ex ex, std::pmr::memory_resource* mr)
685   
{
685   
{
686   
    return detail::run_wrapper_ex<Ex, true, std::pmr::memory_resource*>{
686   
    return detail::run_wrapper_ex<Ex, true, std::pmr::memory_resource*>{
687   
        std::move(ex), mr};
687   
        std::move(ex), mr};
688   
}
688   
}
689  
689  
690   
/** Bind a task to an executor with a standard allocator.
690   
/** Bind a task to an executor with a standard allocator.
691  
691  
692   
    @param ex The executor on which the task should run.
692   
    @param ex The executor on which the task should run.
693   
    @param alloc The allocator for frame allocation.
693   
    @param alloc The allocator for frame allocation.
694  
694  
695   
    @return A wrapper that accepts a task for execution.
695   
    @return A wrapper that accepts a task for execution.
696   
*/
696   
*/
697   
template<Executor Ex, detail::Allocator Alloc>
697   
template<Executor Ex, detail::Allocator Alloc>
698   
[[nodiscard]] auto
698   
[[nodiscard]] auto
699   
run(Ex ex, Alloc alloc)
699   
run(Ex ex, Alloc alloc)
700   
{
700   
{
701   
    return detail::run_wrapper_ex<Ex, true, Alloc>{
701   
    return detail::run_wrapper_ex<Ex, true, Alloc>{
702   
        std::move(ex), std::move(alloc)};
702   
        std::move(ex), std::move(alloc)};
703   
}
703   
}
704  
704  
705   
/** Bind a task to an executor with stop token and memory resource.
705   
/** Bind a task to an executor with stop token and memory resource.
706  
706  
707   
    @param ex The executor on which the task should run.
707   
    @param ex The executor on which the task should run.
708   
    @param st The stop token for cooperative cancellation.
708   
    @param st The stop token for cooperative cancellation.
709   
    @param mr The memory resource for frame allocation.
709   
    @param mr The memory resource for frame allocation.
710  
710  
711   
    @return A wrapper that accepts a task for execution.
711   
    @return A wrapper that accepts a task for execution.
712   
*/
712   
*/
713   
template<Executor Ex>
713   
template<Executor Ex>
714   
[[nodiscard]] auto
714   
[[nodiscard]] auto
715   
run(Ex ex, std::stop_token st, std::pmr::memory_resource* mr)
715   
run(Ex ex, std::stop_token st, std::pmr::memory_resource* mr)
716   
{
716   
{
717   
    return detail::run_wrapper_ex<Ex, false, std::pmr::memory_resource*>{
717   
    return detail::run_wrapper_ex<Ex, false, std::pmr::memory_resource*>{
718   
        std::move(ex), std::move(st), mr};
718   
        std::move(ex), std::move(st), mr};
719   
}
719   
}
720  
720  
721   
/** Bind a task to an executor with stop token and standard allocator.
721   
/** Bind a task to an executor with stop token and standard allocator.
722  
722  
723   
    @param ex The executor on which the task should run.
723   
    @param ex The executor on which the task should run.
724   
    @param st The stop token for cooperative cancellation.
724   
    @param st The stop token for cooperative cancellation.
725   
    @param alloc The allocator for frame allocation.
725   
    @param alloc The allocator for frame allocation.
726  
726  
727   
    @return A wrapper that accepts a task for execution.
727   
    @return A wrapper that accepts a task for execution.
728   
*/
728   
*/
729   
template<Executor Ex, detail::Allocator Alloc>
729   
template<Executor Ex, detail::Allocator Alloc>
730   
[[nodiscard]] auto
730   
[[nodiscard]] auto
731   
run(Ex ex, std::stop_token st, Alloc alloc)
731   
run(Ex ex, std::stop_token st, Alloc alloc)
732   
{
732   
{
733   
    return detail::run_wrapper_ex<Ex, false, Alloc>{
733   
    return detail::run_wrapper_ex<Ex, false, Alloc>{
734   
        std::move(ex), std::move(st), std::move(alloc)};
734   
        std::move(ex), std::move(st), std::move(alloc)};
735   
}
735   
}
736  
736  
737   
//----------------------------------------------------------
737   
//----------------------------------------------------------
738   
//
738   
//
739   
// run() overloads - no executor (inherits caller's)
739   
// run() overloads - no executor (inherits caller's)
740   
//
740   
//
741   
//----------------------------------------------------------
741   
//----------------------------------------------------------
742  
742  
743   
/** Run a task with a custom stop token.
743   
/** Run a task with a custom stop token.
744  
744  
745   
    The task inherits the caller's executor. Only the stop token
745   
    The task inherits the caller's executor. Only the stop token
746   
    is overridden.
746   
    is overridden.
747  
747  
748   
    @par Example
748   
    @par Example
749   
    @code
749   
    @code
750   
    std::stop_source source;
750   
    std::stop_source source;
751   
    co_await run(source.get_token())(cancellable_task());
751   
    co_await run(source.get_token())(cancellable_task());
752   
    @endcode
752   
    @endcode
753  
753  
754   
    @param st The stop token for cooperative cancellation.
754   
    @param st The stop token for cooperative cancellation.
755  
755  
756   
    @return A wrapper that accepts a task for execution.
756   
    @return A wrapper that accepts a task for execution.
757   
*/
757   
*/
758   
[[nodiscard]] inline auto
758   
[[nodiscard]] inline auto
759   
run(std::stop_token st)
759   
run(std::stop_token st)
760   
{
760   
{
761   
    return detail::run_wrapper<false, void>{std::move(st)};
761   
    return detail::run_wrapper<false, void>{std::move(st)};
762   
}
762   
}
763  
763  
764   
/** Run a task with a custom memory resource.
764   
/** Run a task with a custom memory resource.
765  
765  
766   
    The task inherits the caller's executor. The memory resource
766   
    The task inherits the caller's executor. The memory resource
767   
    is used for nested frame allocations.
767   
    is used for nested frame allocations.
768  
768  
769   
    @param mr The memory resource for frame allocation.
769   
    @param mr The memory resource for frame allocation.
770  
770  
771   
    @return A wrapper that accepts a task for execution.
771   
    @return A wrapper that accepts a task for execution.
772   
*/
772   
*/
773   
[[nodiscard]] inline auto
773   
[[nodiscard]] inline auto
774   
run(std::pmr::memory_resource* mr)
774   
run(std::pmr::memory_resource* mr)
775   
{
775   
{
776   
    return detail::run_wrapper<true, std::pmr::memory_resource*>{mr};
776   
    return detail::run_wrapper<true, std::pmr::memory_resource*>{mr};
777   
}
777   
}
778  
778  
779   
/** Run a task with a custom standard allocator.
779   
/** Run a task with a custom standard allocator.
780  
780  
781   
    The task inherits the caller's executor. The allocator is used
781   
    The task inherits the caller's executor. The allocator is used
782   
    for nested frame allocations.
782   
    for nested frame allocations.
783  
783  
784   
    @param alloc The allocator for frame allocation.
784   
    @param alloc The allocator for frame allocation.
785  
785  
786   
    @return A wrapper that accepts a task for execution.
786   
    @return A wrapper that accepts a task for execution.
787   
*/
787   
*/
788   
template<detail::Allocator Alloc>
788   
template<detail::Allocator Alloc>
789   
[[nodiscard]] auto
789   
[[nodiscard]] auto
790   
run(Alloc alloc)
790   
run(Alloc alloc)
791   
{
791   
{
792   
    return detail::run_wrapper<true, Alloc>{std::move(alloc)};
792   
    return detail::run_wrapper<true, Alloc>{std::move(alloc)};
793   
}
793   
}
794  
794  
795   
/** Run a task with stop token and memory resource.
795   
/** Run a task with stop token and memory resource.
796  
796  
797   
    The task inherits the caller's executor.
797   
    The task inherits the caller's executor.
798  
798  
799   
    @param st The stop token for cooperative cancellation.
799   
    @param st The stop token for cooperative cancellation.
800   
    @param mr The memory resource for frame allocation.
800   
    @param mr The memory resource for frame allocation.
801  
801  
802   
    @return A wrapper that accepts a task for execution.
802   
    @return A wrapper that accepts a task for execution.
803   
*/
803   
*/
804   
[[nodiscard]] inline auto
804   
[[nodiscard]] inline auto
805   
run(std::stop_token st, std::pmr::memory_resource* mr)
805   
run(std::stop_token st, std::pmr::memory_resource* mr)
806   
{
806   
{
807   
    return detail::run_wrapper<false, std::pmr::memory_resource*>{
807   
    return detail::run_wrapper<false, std::pmr::memory_resource*>{
808   
        std::move(st), mr};
808   
        std::move(st), mr};
809   
}
809   
}
810  
810  
811   
/** Run a task with stop token and standard allocator.
811   
/** Run a task with stop token and standard allocator.
812  
812  
813   
    The task inherits the caller's executor.
813   
    The task inherits the caller's executor.
814  
814  
815   
    @param st The stop token for cooperative cancellation.
815   
    @param st The stop token for cooperative cancellation.
816   
    @param alloc The allocator for frame allocation.
816   
    @param alloc The allocator for frame allocation.
817  
817  
818   
    @return A wrapper that accepts a task for execution.
818   
    @return A wrapper that accepts a task for execution.
819   
*/
819   
*/
820   
template<detail::Allocator Alloc>
820   
template<detail::Allocator Alloc>
821   
[[nodiscard]] auto
821   
[[nodiscard]] auto
822   
run(std::stop_token st, Alloc alloc)
822   
run(std::stop_token st, Alloc alloc)
823   
{
823   
{
824   
    return detail::run_wrapper<false, Alloc>{
824   
    return detail::run_wrapper<false, Alloc>{
825   
        std::move(st), std::move(alloc)};
825   
        std::move(st), std::move(alloc)};
826   
}
826   
}
827  
827  
828   
} // namespace boost::capy
828   
} // namespace boost::capy
829  
829  
830   
#endif
830   
#endif