. /include/boost/corosio /detail /timer_service.hpp
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1   // 1   //
2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com) 2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   // Copyright (c) 2026 Steve Gerbino 3   // Copyright (c) 2026 Steve Gerbino
4   // 4   //
5   // Distributed under the Boost Software License, Version 1.0. (See accompanying 5   // Distributed under the Boost Software License, Version 1.0. (See accompanying
6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7   // 7   //
8   // Official repository: https://github.com/cppalliance/corosio 8   // Official repository: https://github.com/cppalliance/corosio
9   // 9   //
10   10  
11   #ifndef BOOST_COROSIO_DETAIL_TIMER_SERVICE_HPP 11   #ifndef BOOST_COROSIO_DETAIL_TIMER_SERVICE_HPP
12   #define BOOST_COROSIO_DETAIL_TIMER_SERVICE_HPP 12   #define BOOST_COROSIO_DETAIL_TIMER_SERVICE_HPP
13   13  
14   #include <boost/corosio/detail/timer.hpp> 14   #include <boost/corosio/detail/timer.hpp>
15   #include <boost/corosio/detail/scheduler.hpp> 15   #include <boost/corosio/detail/scheduler.hpp>
16   #include <boost/corosio/detail/scheduler_op.hpp> 16   #include <boost/corosio/detail/scheduler_op.hpp>
17   #include <boost/corosio/detail/intrusive.hpp> 17   #include <boost/corosio/detail/intrusive.hpp>
18   #include <boost/corosio/detail/thread_local_ptr.hpp> 18   #include <boost/corosio/detail/thread_local_ptr.hpp>
19   #include <boost/capy/error.hpp> 19   #include <boost/capy/error.hpp>
20   #include <boost/capy/ex/execution_context.hpp> 20   #include <boost/capy/ex/execution_context.hpp>
21   #include <boost/capy/ex/executor_ref.hpp> 21   #include <boost/capy/ex/executor_ref.hpp>
22   #include <system_error> 22   #include <system_error>
23   23  
24   #include <atomic> 24   #include <atomic>
25   #include <chrono> 25   #include <chrono>
26   #include <coroutine> 26   #include <coroutine>
27   #include <cstddef> 27   #include <cstddef>
28   #include <limits> 28   #include <limits>
29   #include <mutex> 29   #include <mutex>
30   #include <stop_token> 30   #include <stop_token>
31   #include <utility> 31   #include <utility>
32   #include <vector> 32   #include <vector>
33   33  
34   namespace boost::corosio::detail { 34   namespace boost::corosio::detail {
35   35  
36   struct scheduler; 36   struct scheduler;
37   37  
38   /* 38   /*
39   Timer Service 39   Timer Service
40   ============= 40   =============
41   41  
42   Data Structures 42   Data Structures
43   --------------- 43   ---------------
44   waiter_node (defined in timer.hpp) holds per-waiter state: 44   waiter_node (defined in timer.hpp) holds per-waiter state:
45   coroutine handle, executor, error output, embedded 45   coroutine handle, executor, error output, embedded
46   completion_op. Each concurrent co_await t.wait() embeds one 46   completion_op. Each concurrent co_await t.wait() embeds one
47   waiter_node in the awaitable on the suspended coroutine's 47   waiter_node in the awaitable on the suspended coroutine's
48   frame — waits perform no allocation. 48   frame — waits perform no allocation.
49   49  
50   timer::implementation holds per-timer state: expiry, heap 50   timer::implementation holds per-timer state: expiry, heap
51   index, and the single published waiter. Each timer holds 51   index, and the single published waiter. Each timer holds
52   at most one waiter; process_expired's local cross-timer drain 52   at most one waiter; process_expired's local cross-timer drain
53   list still threads waiters through their intrusive hooks when 53   list still threads waiters through their intrusive hooks when
54   collecting several timers' waiters past the lock. 54   collecting several timers' waiters past the lock.
55   55  
56   timer_service owns a min-heap of active timers and a free list 56   timer_service owns a min-heap of active timers and a free list
57   of recycled impls. The heap is ordered by expiry time; the 57   of recycled impls. The heap is ordered by expiry time; the
58   scheduler queries nearest_expiry() to set the epoll/timerfd 58   scheduler queries nearest_expiry() to set the epoll/timerfd
59   timeout. 59   timeout.
60   60  
61   Optimization Strategy 61   Optimization Strategy
62   --------------------- 62   ---------------------
63   1. Deferred heap insertion — expires_after() stores the expiry 63   1. Deferred heap insertion — expires_after() stores the expiry
64   but does not insert into the heap. Insertion happens in wait(). 64   but does not insert into the heap. Insertion happens in wait().
65   2. Thread-local impl cache — single-slot per-thread cache. 65   2. Thread-local impl cache — single-slot per-thread cache.
66   3. Frame-resident waiter_node with embedded completion_op — 66   3. Frame-resident waiter_node with embedded completion_op —
67   eliminates heap allocation per wait/fire/cancel. 67   eliminates heap allocation per wait/fire/cancel.
68   4. Cached nearest expiry — atomic avoids mutex in nearest_expiry(). 68   4. Cached nearest expiry — atomic avoids mutex in nearest_expiry().
69   5. might_have_pending_waits_ flag — skips lock when no wait issued. 69   5. might_have_pending_waits_ flag — skips lock when no wait issued.
70   70  
71   Concurrency 71   Concurrency
72   ----------- 72   -----------
73   stop_token callbacks can fire from any thread. The impl_ 73   stop_token callbacks can fire from any thread. The impl_
74   pointer on waiter_node is used as a "still in list" marker. 74   pointer on waiter_node is used as a "still in list" marker.
75   A waiter_node's storage is the suspended coroutine's frame: 75   A waiter_node's storage is the suspended coroutine's frame:
76   every completion path must finish touching the node before 76   every completion path must finish touching the node before
77   posting the continuation or destroying the handle. 77   posting the continuation or destroying the handle.
78   */ 78   */
79   79  
80   inline void timer_service_invalidate_cache() noexcept; 80   inline void timer_service_invalidate_cache() noexcept;
81   81  
82   // timer_service class body — member function definitions are 82   // timer_service class body — member function definitions are
83   // out-of-class (after implementation and waiter_node are complete) 83   // out-of-class (after implementation and waiter_node are complete)
84   class BOOST_COROSIO_DECL timer_service final 84   class BOOST_COROSIO_DECL timer_service final
85   : public capy::execution_context::service 85   : public capy::execution_context::service
86   , public io_object::io_service 86   , public io_object::io_service
87   { 87   {
88   public: 88   public:
89   using clock_type = std::chrono::steady_clock; 89   using clock_type = std::chrono::steady_clock;
90   using time_point = clock_type::time_point; 90   using time_point = clock_type::time_point;
91   91  
92   /// Type-erased callback for earliest-expiry-changed notifications. 92   /// Type-erased callback for earliest-expiry-changed notifications.
93   class callback 93   class callback
94   { 94   {
95   void* ctx_ = nullptr; 95   void* ctx_ = nullptr;
96   void (*fn_)(void*) = nullptr; 96   void (*fn_)(void*) = nullptr;
97   97  
98   public: 98   public:
99   /// Construct an empty callback. 99   /// Construct an empty callback.
HITCBC 100   1603 callback() = default; 100   1790 callback() = default;
101   101  
102   /// Construct a callback with the given context and function. 102   /// Construct a callback with the given context and function.
HITCBC 103   1603 callback(void* ctx, void (*fn)(void*)) noexcept : ctx_(ctx), fn_(fn) {} 103   1790 callback(void* ctx, void (*fn)(void*)) noexcept : ctx_(ctx), fn_(fn) {}
104   104  
105   /// Return true if the callback is non-empty. 105   /// Return true if the callback is non-empty.
106   explicit operator bool() const noexcept 106   explicit operator bool() const noexcept
107   { 107   {
108   return fn_ != nullptr; 108   return fn_ != nullptr;
109   } 109   }
110   110  
111   /// Invoke the callback. 111   /// Invoke the callback.
HITCBC 112   5800 void operator()() const 112   6840 void operator()() const
113   { 113   {
HITCBC 114   5800 if (fn_) 114   6840 if (fn_)
HITCBC 115   5800 fn_(ctx_); 115   6840 fn_(ctx_);
HITCBC 116   5800 } 116   6840 }
117   }; 117   };
118   118  
119   private: 119   private:
120   struct heap_entry 120   struct heap_entry
121   { 121   {
122   time_point time_; 122   time_point time_;
123   timer::implementation* timer_; 123   timer::implementation* timer_;
124   }; 124   };
125   125  
126   scheduler* sched_ = nullptr; 126   scheduler* sched_ = nullptr;
127   BOOST_COROSIO_MSVC_WARNING_PUSH 127   BOOST_COROSIO_MSVC_WARNING_PUSH
128   BOOST_COROSIO_MSVC_WARNING_DISABLE(4251) // std:: members, dll-interface 128   BOOST_COROSIO_MSVC_WARNING_DISABLE(4251) // std:: members, dll-interface
129   mutable std::mutex mutex_; 129   mutable std::mutex mutex_;
130   std::vector<heap_entry> heap_; 130   std::vector<heap_entry> heap_;
131   timer::implementation* free_list_ = nullptr; 131   timer::implementation* free_list_ = nullptr;
132   callback on_earliest_changed_; 132   callback on_earliest_changed_;
133   bool shutting_down_ = false; 133   bool shutting_down_ = false;
134   // Avoids mutex in nearest_expiry() and empty() 134   // Avoids mutex in nearest_expiry() and empty()
135   mutable std::atomic<std::int64_t> cached_nearest_ns_{ 135   mutable std::atomic<std::int64_t> cached_nearest_ns_{
136   (std::numeric_limits<std::int64_t>::max)()}; 136   (std::numeric_limits<std::int64_t>::max)()};
137   BOOST_COROSIO_MSVC_WARNING_POP 137   BOOST_COROSIO_MSVC_WARNING_POP
138   138  
139   public: 139   public:
140   /// Construct the timer service bound to a scheduler. 140   /// Construct the timer service bound to a scheduler.
HITCBC 141   1603 inline timer_service(capy::execution_context&, scheduler& sched) 141   1790 inline timer_service(capy::execution_context&, scheduler& sched)
HITCBC 142   1603 : sched_(&sched) 142   1790 : sched_(&sched)
143   { 143   {
HITCBC 144   1603 } 144   1790 }
145   145  
146   /// Return the associated scheduler. 146   /// Return the associated scheduler.
HITCBC 147   12060 inline scheduler& get_scheduler() noexcept 147   13957 inline scheduler& get_scheduler() noexcept
148   { 148   {
HITCBC 149   12060 return *sched_; 149   13957 return *sched_;
150   } 150   }
151   151  
152   /// Destroy the timer service. 152   /// Destroy the timer service.
HITCBC 153   3206 ~timer_service() override = default; 153   3580 ~timer_service() override = default;
154   154  
155   timer_service(timer_service const&) = delete; 155   timer_service(timer_service const&) = delete;
156   timer_service& operator=(timer_service const&) = delete; 156   timer_service& operator=(timer_service const&) = delete;
157   157  
158   /// Register a callback invoked when the earliest expiry changes. 158   /// Register a callback invoked when the earliest expiry changes.
HITCBC 159   1603 inline void set_on_earliest_changed(callback cb) 159   1790 inline void set_on_earliest_changed(callback cb)
160   { 160   {
HITCBC 161   1603 on_earliest_changed_ = cb; 161   1790 on_earliest_changed_ = cb;
HITCBC 162   1603 } 162   1790 }
163   163  
164   /// Return true if no timers are in the heap. 164   /// Return true if no timers are in the heap.
165   inline bool empty() const noexcept 165   inline bool empty() const noexcept
166   { 166   {
167   return cached_nearest_ns_.load(std::memory_order_acquire) == 167   return cached_nearest_ns_.load(std::memory_order_acquire) ==
168   (std::numeric_limits<std::int64_t>::max)(); 168   (std::numeric_limits<std::int64_t>::max)();
169   } 169   }
170   170  
171   /// Return the nearest timer expiry without acquiring the mutex. 171   /// Return the nearest timer expiry without acquiring the mutex.
HITCBC 172   296272 inline time_point nearest_expiry() const noexcept 172   347089 inline time_point nearest_expiry() const noexcept
173   { 173   {
HITCBC 174   296272 auto ns = cached_nearest_ns_.load(std::memory_order_acquire); 174   347089 auto ns = cached_nearest_ns_.load(std::memory_order_acquire);
HITCBC 175   296272 return time_point(time_point::duration(ns)); 175   347089 return time_point(time_point::duration(ns));
176   } 176   }
177   177  
178   /// Cancel all pending timers and free cached resources. 178   /// Cancel all pending timers and free cached resources.
179   inline void shutdown() override; 179   inline void shutdown() override;
180   180  
181   /// Construct a new timer implementation. 181   /// Construct a new timer implementation.
182   inline io_object::implementation* construct() override; 182   inline io_object::implementation* construct() override;
183   183  
184   /// Destroy a timer implementation, cancelling pending waiters. 184   /// Destroy a timer implementation, cancelling pending waiters.
185   inline void destroy(io_object::implementation* p) override; 185   inline void destroy(io_object::implementation* p) override;
186   186  
187   /// Cancel and recycle a timer implementation. 187   /// Cancel and recycle a timer implementation.
188   inline void destroy_impl(timer::implementation& impl); 188   inline void destroy_impl(timer::implementation& impl);
189   189  
190   /// Publish the timer's waiter and insert the timer into the heap. 190   /// Publish the timer's waiter and insert the timer into the heap.
191   inline void insert_waiter(timer::implementation& impl, waiter_node* w); 191   inline void insert_waiter(timer::implementation& impl, waiter_node* w);
192   192  
193   /// Cancel the timer's published waiter, if any. 193   /// Cancel the timer's published waiter, if any.
194   inline void cancel_timer(timer::implementation& impl); 194   inline void cancel_timer(timer::implementation& impl);
195   195  
196   /// Cancel one specific waiter ( stop_token callback path ). 196   /// Cancel one specific waiter ( stop_token callback path ).
197   inline void cancel_waiter(waiter_node* w); 197   inline void cancel_waiter(waiter_node* w);
198   198  
199   /// Complete all waiters whose timers have expired. 199   /// Complete all waiters whose timers have expired.
200   inline std::size_t process_expired(); 200   inline std::size_t process_expired();
201   201  
202   private: 202   private:
HITCBC 203   323374 inline void refresh_cached_nearest() noexcept 203   374911 inline void refresh_cached_nearest() noexcept
204   { 204   {
HITCBC 205   323374 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)() 205   374911 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)()
HITCBC 206   319949 : heap_[0].time_.time_since_epoch().count(); 206   371183 : heap_[0].time_.time_since_epoch().count();
HITCBC 207   323374 cached_nearest_ns_.store(ns, std::memory_order_release); 207   374911 cached_nearest_ns_.store(ns, std::memory_order_release);
HITCBC 208   323374 } 208   374911 }
209   209  
210   inline void remove_timer_impl(timer::implementation& impl); 210   inline void remove_timer_impl(timer::implementation& impl);
211   inline void up_heap(std::size_t index); 211   inline void up_heap(std::size_t index);
212   inline void down_heap(std::size_t index); 212   inline void down_heap(std::size_t index);
213   inline void swap_heap(std::size_t i1, std::size_t i2); 213   inline void swap_heap(std::size_t i1, std::size_t i2);
214   }; 214   };
215   215  
216   // Thread-local cache avoids hot-path mutex acquisitions: 216   // Thread-local cache avoids hot-path mutex acquisitions:
217   // single-slot impl cache, validated by comparing svc_. Cleared by 217   // single-slot impl cache, validated by comparing svc_. Cleared by
218   // timer_service_invalidate_cache() during shutdown. 218   // timer_service_invalidate_cache() during shutdown.
219   219  
220   inline thread_local_ptr<timer::implementation> tl_cached_impl; 220   inline thread_local_ptr<timer::implementation> tl_cached_impl;
221   221  
222   // The POD TLS slot above never runs destructors, so a short-lived 222   // The POD TLS slot above never runs destructors, so a short-lived
223   // run() thread would leak its cached impl. Each push arms this 223   // run() thread would leak its cached impl. Each push arms this
224   // owner, whose destructor frees the slot at thread exit. A cached 224   // owner, whose destructor frees the slot at thread exit. A cached
225   // entry is a quiescent heap object (nothing in the heap or free 225   // entry is a quiescent heap object (nothing in the heap or free
226   // list) and deletion touches no service state, so it is safe after 226   // list) and deletion touches no service state, so it is safe after
227   // the owning service is gone (the stale-entry path in 227   // the owning service is gone (the stale-entry path in
228   // try_pop_tl_cache deletes the same way). 228   // try_pop_tl_cache deletes the same way).
229   struct tl_cache_owner 229   struct tl_cache_owner
230   { 230   {
HITCBC 231   41 ~tl_cache_owner() 231   40 ~tl_cache_owner()
232   { 232   {
HITCBC 233   41 delete tl_cached_impl.get(); 233   40 delete tl_cached_impl.get();
HITCBC 234   41 tl_cached_impl.set(nullptr); 234   40 tl_cached_impl.set(nullptr);
HITCBC 235   41 } 235   40 }
236   }; 236   };
237   237  
238   inline void 238   inline void
HITCBC 239   6761 arm_tl_cache_cleanup() noexcept 239   7653 arm_tl_cache_cleanup() noexcept
240   { 240   {
HITCBC 241   6761 [[maybe_unused]] thread_local tl_cache_owner owner; 241   7653 [[maybe_unused]] thread_local tl_cache_owner owner;
HITCBC 242   6761 } 242   7653 }
243   243  
244   inline timer::implementation* 244   inline timer::implementation*
HITCBC 245   6895 try_pop_tl_cache(timer_service* svc) noexcept 245   7844 try_pop_tl_cache(timer_service* svc) noexcept
246   { 246   {
HITCBC 247   6895 auto* impl = tl_cached_impl.get(); 247   7844 auto* impl = tl_cached_impl.get();
HITCBC 248   6895 if (impl) 248   7844 if (impl)
249   { 249   {
HITCBC 250   6486 tl_cached_impl.set(nullptr); 250   7362 tl_cached_impl.set(nullptr);
HITCBC 251   6486 if (impl->svc_ == svc) 251   7362 if (impl->svc_ == svc)
HITCBC 252   6486 return impl; 252   7362 return impl;
253   // Stale impl from a destroyed service 253   // Stale impl from a destroyed service
MISUBC 254   ✗ delete impl; 254   ✗ delete impl;
255   } 255   }
HITCBC 256   409 return nullptr; 256   482 return nullptr;
257   } 257   }
258   258  
259   inline bool 259   inline bool
HITCBC 260   6867 try_push_tl_cache(timer::implementation* impl) noexcept 260   7815 try_push_tl_cache(timer::implementation* impl) noexcept
261   { 261   {
HITCBC 262   6867 if (!tl_cached_impl.get()) 262   7815 if (!tl_cached_impl.get())
263   { 263   {
HITCBC 264   6761 arm_tl_cache_cleanup(); 264   7653 arm_tl_cache_cleanup();
HITCBC 265   6761 tl_cached_impl.set(impl); 265   7653 tl_cached_impl.set(impl);
HITCBC 266   6761 return true; 266   7653 return true;
267   } 267   }
HITCBC 268   106 return false; 268   162 return false;
269   } 269   }
270   270  
271   inline void 271   inline void
HITCBC 272   1603 timer_service_invalidate_cache() noexcept 272   1790 timer_service_invalidate_cache() noexcept
273   { 273   {
HITCBC 274   1603 delete tl_cached_impl.get(); 274   1790 delete tl_cached_impl.get();
HITCBC 275   1603 tl_cached_impl.set(nullptr); 275   1790 tl_cached_impl.set(nullptr);
HITCBC 276   1603 } 276   1790 }
277   277  
278   // timer_service out-of-class member function definitions 278   // timer_service out-of-class member function definitions
279   279  
280   inline void 280   inline void
HITCBC 281   1603 timer_service::shutdown() 281   1790 timer_service::shutdown()
282   { 282   {
HITCBC 283   1603 timer_service_invalidate_cache(); 283   1790 timer_service_invalidate_cache();
HITCBC 284   1603 shutting_down_ = true; 284   1790 shutting_down_ = true;
285   285  
286   // Snapshot impls and detach them from the heap so that 286   // Snapshot impls and detach them from the heap so that
287   // coroutine-owned timer destructors (triggered by h.destroy() 287   // coroutine-owned timer destructors (triggered by h.destroy()
288   // below) cannot re-enter remove_timer_impl() and mutate the 288   // below) cannot re-enter remove_timer_impl() and mutate the
289   // vector during iteration. 289   // vector during iteration.
HITCBC 290   1603 std::vector<timer::implementation*> impls; 290   1790 std::vector<timer::implementation*> impls;
HITCBC 291   1603 impls.reserve(heap_.size()); 291   1790 impls.reserve(heap_.size());
HITCBC 292   1631 for (auto& entry : heap_) 292   1819 for (auto& entry : heap_)
293   { 293   {
HITCBC 294   28 entry.timer_->heap_index_.store( 294   29 entry.timer_->heap_index_.store(
295   (std::numeric_limits<std::size_t>::max)(), 295   (std::numeric_limits<std::size_t>::max)(),
296   std::memory_order_relaxed); 296   std::memory_order_relaxed);
HITCBC 297   28 impls.push_back(entry.timer_); 297   29 impls.push_back(entry.timer_);
298   } 298   }
HITCBC 299   1603 heap_.clear(); 299   1790 heap_.clear();
HITCBC 300   1603 cached_nearest_ns_.store( 300   1790 cached_nearest_ns_.store(
301   (std::numeric_limits<std::int64_t>::max)(), std::memory_order_release); 301   (std::numeric_limits<std::int64_t>::max)(), std::memory_order_release);
302   302  
303   // Cancel waiting timers. Each waiter called work_started() 303   // Cancel waiting timers. Each waiter called work_started()
304   // in implementation::wait(). On IOCP the scheduler shutdown 304   // in implementation::wait(). On IOCP the scheduler shutdown
305   // loop exits when outstanding_work_ reaches zero, so we must 305   // loop exits when outstanding_work_ reaches zero, so we must
306   // call work_finished() here to balance it. On other backends 306   // call work_finished() here to balance it. On other backends
307   // this is harmless. 307   // this is harmless.
HITCBC 308   1631 for (auto* impl : impls) 308   1819 for (auto* impl : impls)
309   { 309   {
HITCBC 310   28 if (auto* w = std::exchange(impl->waiter_, nullptr)) 310   29 if (auto* w = std::exchange(impl->waiter_, nullptr))
311   { 311   {
HITCBC 312   28 w->reset_stop_cb(); 312   29 w->reset_stop_cb();
HITCBC 313   28 auto h = std::exchange(w->h_, {}); 313   29 auto h = std::exchange(w->h_, {});
HITCBC 314   28 sched_->work_finished(); 314   29 sched_->work_finished();
315   // Destroying the frame also ends the node's storage 315   // Destroying the frame also ends the node's storage
HITCBC 316   28 if (h) 316   29 if (h)
HITCBC 317   28 h.destroy(); 317   29 h.destroy();
318   } 318   }
HITCBC 319   28 delete impl; 319   29 delete impl;
320   } 320   }
321   321  
322   // Delete free-listed impls 322   // Delete free-listed impls
HITCBC 323   1707 while (free_list_) 323   1950 while (free_list_)
324   { 324   {
HITCBC 325   104 auto* next = free_list_->next_free_; 325   160 auto* next = free_list_->next_free_;
HITCBC 326   104 delete free_list_; 326   160 delete free_list_;
HITCBC 327   104 free_list_ = next; 327   160 free_list_ = next;
328   } 328   }
HITCBC 329   1603 } 329   1790 }
330   330  
331   inline io_object::implementation* 331   inline io_object::implementation*
HITCBC 332   6895 timer_service::construct() 332   7844 timer_service::construct()
333   { 333   {
HITCBC 334   6895 timer::implementation* impl = try_pop_tl_cache(this); 334   7844 timer::implementation* impl = try_pop_tl_cache(this);
HITCBC 335   6895 if (impl) 335   7844 if (impl)
336   { 336   {
HITCBC 337   6486 impl->svc_ = this; 337   7362 impl->svc_ = this;
338   // Reset expiry_ too: a recycled impl must behave like a fresh 338   // Reset expiry_ too: a recycled impl must behave like a fresh
339   // one, whose default expiry reads as already elapsed 339   // one, whose default expiry reads as already elapsed
HITCBC 340   6486 impl->expiry_ = {}; 340   7362 impl->expiry_ = {};
HITCBC 341   6486 impl->heap_index_.store( 341   7362 impl->heap_index_.store(
342   (std::numeric_limits<std::size_t>::max)(), 342   (std::numeric_limits<std::size_t>::max)(),
343   std::memory_order_relaxed); 343   std::memory_order_relaxed);
HITCBC 344   6486 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 344   7362 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 345   6486 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr); 345   7362 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr);
HITCBC 346   6486 return impl; 346   7362 return impl;
347   } 347   }
348   348  
HITCBC 349   409 std::lock_guard lock(mutex_); 349   482 std::lock_guard lock(mutex_);
HITCBC 350   409 if (free_list_) 350   482 if (free_list_)
351   { 351   {
HITCBC 352   2 impl = free_list_; 352   2 impl = free_list_;
HITCBC 353   2 free_list_ = impl->next_free_; 353   2 free_list_ = impl->next_free_;
HITCBC 354   2 impl->next_free_ = nullptr; 354   2 impl->next_free_ = nullptr;
HITCBC 355   2 impl->svc_ = this; 355   2 impl->svc_ = this;
HITCBC 356   2 impl->expiry_ = {}; 356   2 impl->expiry_ = {};
HITCBC 357   2 impl->heap_index_.store( 357   2 impl->heap_index_.store(
358   (std::numeric_limits<std::size_t>::max)(), 358   (std::numeric_limits<std::size_t>::max)(),
359   std::memory_order_relaxed); 359   std::memory_order_relaxed);
HITCBC 360   2 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 360   2 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 361   2 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr); 361   2 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr);
362   } 362   }
363   else 363   else
364   { 364   {
HITCBC 365   407 impl = new timer::implementation(*this); 365   480 impl = new timer::implementation(*this);
366   } 366   }
HITCBC 367   409 return impl; 367   482 return impl;
HITCBC 368   409 } 368   482 }
369   369  
370   inline void 370   inline void
HITCBC 371   6895 timer_service::destroy(io_object::implementation* p) 371   7844 timer_service::destroy(io_object::implementation* p)
372   { 372   {
373   // During shutdown the drain loop owns every impl and deletes 373   // During shutdown the drain loop owns every impl and deletes
374   // them directly. A frame destroyed by that loop can unwind a 374   // them directly. A frame destroyed by that loop can unwind a
375   // handle whose impl was freed in an earlier iteration (a 375   // handle whose impl was freed in an earlier iteration (a
376   // timeout's parent frame owns the timeout timer while 376   // timeout's parent frame owns the timeout timer while
377   // suspended on the inner delay's timer), so bail out before 377   // suspended on the inner delay's timer), so bail out before
378   // even downcasting the pointer. 378   // even downcasting the pointer.
HITCBC 379   6895 if (shutting_down_) 379   7844 if (shutting_down_)
HITCBC 380   28 return; 380   29 return;
HITCBC 381   6867 destroy_impl(static_cast<timer::implementation&>(*p)); 381   7815 destroy_impl(static_cast<timer::implementation&>(*p));
382   } 382   }
383   383  
384   inline void 384   inline void
HITCBC 385   6867 timer_service::destroy_impl(timer::implementation& impl) 385   7815 timer_service::destroy_impl(timer::implementation& impl)
386   { 386   {
387   // During shutdown the impl is owned by the shutdown loop. 387   // During shutdown the impl is owned by the shutdown loop.
388   // Re-entering here (from a coroutine-owned timer destructor 388   // Re-entering here (from a coroutine-owned timer destructor
389   // triggered by h.destroy()) must not modify the heap or 389   // triggered by h.destroy()) must not modify the heap or
390   // recycle the impl — shutdown deletes it directly. 390   // recycle the impl — shutdown deletes it directly.
HITCBC 391   6867 if (shutting_down_) 391   7815 if (shutting_down_)
HITCBC 392   6761 return; 392   7653 return;
393   393  
HITCBC 394   6867 cancel_timer(impl); 394   7815 cancel_timer(impl);
395   395  
HITCBC 396   13734 if (impl.heap_index_.load(std::memory_order_relaxed) != 396   15630 if (impl.heap_index_.load(std::memory_order_relaxed) !=
HITCBC 397   6867 (std::numeric_limits<std::size_t>::max)()) 397   7815 (std::numeric_limits<std::size_t>::max)())
398   { 398   {
MISUBC 399   ✗ std::lock_guard lock(mutex_); 399   ✗ std::lock_guard lock(mutex_);
MISUBC 400   ✗ remove_timer_impl(impl); 400   ✗ remove_timer_impl(impl);
MISUBC 401   ✗ refresh_cached_nearest(); 401   ✗ refresh_cached_nearest();
MISUBC 402   ✗ } 402   ✗ }
403   403  
HITCBC 404   6867 if (try_push_tl_cache(&impl)) 404   7815 if (try_push_tl_cache(&impl))
HITCBC 405   6761 return; 405   7653 return;
406   406  
HITCBC 407   106 std::lock_guard lock(mutex_); 407   162 std::lock_guard lock(mutex_);
HITCBC 408   106 impl.next_free_ = free_list_; 408   162 impl.next_free_ = free_list_;
HITCBC 409   106 free_list_ = &impl; 409   162 free_list_ = &impl;
HITCBC 410   106 } 410   162 }
411   411  
412   inline void 412   inline void
HITCBC 413   6111 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w) 413   7005 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w)
414   { 414   {
HITCBC 415   6111 bool notify = false; 415   7005 bool notify = false;
HITCBC 416   6111 bool lost_cancel = false; 416   7005 bool lost_cancel = false;
417   { 417   {
HITCBC 418   6111 std::lock_guard lock(mutex_); 418   7005 std::lock_guard lock(mutex_);
419   // Grow before publishing anything, so the push_back below 419   // Grow before publishing anything, so the push_back below
420   // cannot throw: a failure here leaves the waiter untouched, 420   // cannot throw: a failure here leaves the waiter untouched,
421   // the strong guarantee rearm_wait's recovery relies on. 421   // the strong guarantee rearm_wait's recovery relies on.
HITCBC 422   6111 if (impl.heap_index_.load(std::memory_order_relaxed) == 422   7005 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 423   12222 (std::numeric_limits<std::size_t>::max)() && 423   14010 (std::numeric_limits<std::size_t>::max)() &&
HITCBC 424   6111 heap_.size() == heap_.capacity()) 424   7005 heap_.size() == heap_.capacity())
HITCBC 425   280 heap_.reserve( 425   301 heap_.reserve(
HITCBC 426   280 heap_.capacity() == 0 ? 16 : 2 * heap_.capacity()); 426   301 heap_.capacity() == 0 ? 16 : 2 * heap_.capacity());
427   // Publish: from here the waiter is visible to the fire path and 427   // Publish: from here the waiter is visible to the fire path and
428   // to its own stop callback (impl_ non-null enables cancel_waiter). 428   // to its own stop callback (impl_ non-null enables cancel_waiter).
HITCBC 429   6111 w->impl_ = &impl; 429   7005 w->impl_ = &impl;
HITCBC 430   12222 if (impl.heap_index_.load(std::memory_order_relaxed) == 430   14010 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 431   6111 (std::numeric_limits<std::size_t>::max)()) 431   7005 (std::numeric_limits<std::size_t>::max)())
432   { 432   {
HITCBC 433   6111 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed); 433   7005 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed);
HITCBC 434   6111 heap_.push_back({impl.expiry_, &impl}); 434   7005 heap_.push_back({impl.expiry_, &impl});
HITCBC 435   6111 up_heap(heap_.size() - 1); 435   7005 up_heap(heap_.size() - 1);
HITCBC 436   6111 notify = 436   7005 notify =
HITCBC 437   6111 (impl.heap_index_.load(std::memory_order_relaxed) == 0); 437   7005 (impl.heap_index_.load(std::memory_order_relaxed) == 0);
HITCBC 438   6111 refresh_cached_nearest(); 438   7005 refresh_cached_nearest();
439   } 439   }
HITCBC 440   6111 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr); 440   7005 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr);
HITCBC 441   6111 impl.waiter_ = w; 441   7005 impl.waiter_ = w;
442   442  
443   // Lost-cancel re-check: a stop requested after the canceller was 443   // Lost-cancel re-check: a stop requested after the canceller was
444   // armed in wait() but before this publication found impl_ null 444   // armed in wait() but before this publication found impl_ null
445   // and returned a no-op. Observe it now and undo the insertion. 445   // and returned a no-op. Observe it now and undo the insertion.
HITCBC 446   6111 if (w->token_->stop_requested()) 446   7005 if (w->token_->stop_requested())
447   { 447   {
HITCBC 448   57 w->impl_ = nullptr; 448   3 w->impl_ = nullptr;
HITCBC 449   57 impl.waiter_ = nullptr; 449   3 impl.waiter_ = nullptr;
HITCBC 450   57 remove_timer_impl(impl); 450   3 remove_timer_impl(impl);
HITCBC 451   57 impl.might_have_pending_waits_.store( 451   3 impl.might_have_pending_waits_.store(
452   false, std::memory_order_relaxed); 452   false, std::memory_order_relaxed);
HITCBC 453   57 refresh_cached_nearest(); 453   3 refresh_cached_nearest();
HITCBC 454   57 lost_cancel = true; 454   3 lost_cancel = true;
HITCBC 455   57 notify = false; // insertion undone; nearest unchanged 455   3 notify = false; // insertion undone; nearest unchanged
456   } 456   }
HITCBC 457   6111 } 457   7005 }
HITCBC 458   6111 if (notify) 458   7005 if (notify)
HITCBC 459   5800 on_earliest_changed_(); 459   6840 on_earliest_changed_();
HITCBC 460   6111 if (lost_cancel) 460   7005 if (lost_cancel)
461   { 461   {
HITCBC 462   57 w->ec_ = make_error_code(capy::error::canceled); 462   3 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 463   57 sched_->post(&w->op_); 463   3 sched_->post(&w->op_);
464   } 464   }
HITCBC 465   6111 } 465   7005 }
466   466  
467   inline void 467   inline void
HITCBC 468   6867 timer_service::cancel_timer(timer::implementation& impl) 468   7815 timer_service::cancel_timer(timer::implementation& impl)
469   { 469   {
HITCBC 470   6867 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed)) 470   7815 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed))
HITCBC 471   6865 return; 471   7813 return;
472   472  
473   // No unlocked already-done fast-out here: it would need the 473   // No unlocked already-done fast-out here: it would need the
474   // non-atomic waiter_ (a race with concurrent drains), and an 474   // non-atomic waiter_ (a race with concurrent drains), and an
475   // index-only check is lifetime-unsafe because npos is stored 475   // index-only check is lifetime-unsafe because npos is stored
476   // before the drain finishes touching the impl. A stale-true 476   // before the drain finishes touching the impl. A stale-true
477   // flag is rare with the stateless API; the locked path below 477   // flag is rare with the stateless API; the locked path below
478   // re-validates. 478   // re-validates.
479   479  
HITCBC 480   2 waiter_node* canceled = nullptr; 480   2 waiter_node* canceled = nullptr;
481   481  
482   { 482   {
HITCBC 483   2 std::lock_guard lock(mutex_); 483   2 std::lock_guard lock(mutex_);
HITCBC 484   2 remove_timer_impl(impl); 484   2 remove_timer_impl(impl);
HITCBC 485   2 canceled = std::exchange(impl.waiter_, nullptr); 485   2 canceled = std::exchange(impl.waiter_, nullptr);
HITCBC 486   2 if (canceled) 486   2 if (canceled)
HITCBC 487   2 canceled->impl_ = nullptr; 487   2 canceled->impl_ = nullptr;
488   // Store false as the final touch of the impl under the lock so 488   // Store false as the final touch of the impl under the lock so
489   // a pre-lock false-flag check trusts it unqualified. 489   // a pre-lock false-flag check trusts it unqualified.
HITCBC 490   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed); 490   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 491   2 refresh_cached_nearest(); 491   2 refresh_cached_nearest();
HITCBC 492   2 } 492   2 }
493   493  
HITCBC 494   2 if (canceled) 494   2 if (canceled)
495   { 495   {
HITCBC 496   2 canceled->ec_ = make_error_code(capy::error::canceled); 496   2 canceled->ec_ = make_error_code(capy::error::canceled);
HITCBC 497   2 sched_->post(&canceled->op_); 497   2 sched_->post(&canceled->op_);
498   } 498   }
499   } 499   }
500   500  
501   inline void 501   inline void
HITCBC 502   1455 timer_service::cancel_waiter(waiter_node* w) 502   1462 timer_service::cancel_waiter(waiter_node* w)
503   { 503   {
504   { 504   {
HITCBC 505   1455 std::lock_guard lock(mutex_); 505   1462 std::lock_guard lock(mutex_);
506   // Already removed by another drain: cancel_timer, 506   // Already removed by another drain: cancel_timer,
507   // process_expired, or insert_waiter's lost-cancel recheck 507   // process_expired, or insert_waiter's lost-cancel recheck
HITCBC 508   1455 if (!w->impl_) 508   1462 if (!w->impl_)
HITCBC 509   58 return; 509   3 return;
HITCBC 510   1397 auto* impl = w->impl_; 510   1459 auto* impl = w->impl_;
HITCBC 511   1397 w->impl_ = nullptr; 511   1459 w->impl_ = nullptr;
HITCBC 512   1397 impl->waiter_ = nullptr; 512   1459 impl->waiter_ = nullptr;
HITCBC 513   1397 remove_timer_impl(*impl); 513   1459 remove_timer_impl(*impl);
HITCBC 514   1397 impl->might_have_pending_waits_.store( 514   1459 impl->might_have_pending_waits_.store(
515   false, std::memory_order_relaxed); 515   false, std::memory_order_relaxed);
HITCBC 516   1397 refresh_cached_nearest(); 516   1459 refresh_cached_nearest();
HITCBC 517   1455 } 517   1462 }
518   518  
HITCBC 519   1397 w->ec_ = make_error_code(capy::error::canceled); 519   1459 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 520   1397 sched_->post(&w->op_); 520   1459 sched_->post(&w->op_);
521   } 521   }
522   522  
523   inline std::size_t 523   inline std::size_t
HITCBC 524   315807 timer_service::process_expired() 524   366442 timer_service::process_expired()
525   { 525   {
HITCBC 526   315807 intrusive_list<waiter_node> expired; 526   366442 intrusive_list<waiter_node> expired;
527   527  
528   { 528   {
HITCBC 529   315807 std::lock_guard lock(mutex_); 529   366442 std::lock_guard lock(mutex_);
HITCBC 530   315807 auto now = clock_type::now(); 530   366442 auto now = clock_type::now();
531   531  
HITCBC 532   320434 while (!heap_.empty() && heap_[0].time_ <= now) 532   371954 while (!heap_.empty() && heap_[0].time_ <= now)
533   { 533   {
HITCBC 534   4627 timer::implementation* t = heap_[0].timer_; 534   5512 timer::implementation* t = heap_[0].timer_;
HITCBC 535   4627 remove_timer_impl(*t); 535   5512 remove_timer_impl(*t);
HITCBC 536   4627 if (auto* w = std::exchange(t->waiter_, nullptr)) 536   5512 if (auto* w = std::exchange(t->waiter_, nullptr))
537   { 537   {
HITCBC 538   4627 w->impl_ = nullptr; 538   5512 w->impl_ = nullptr;
HITCBC 539   4627 w->ec_ = {}; 539   5512 w->ec_ = {};
HITCBC 540   4627 expired.push_back(w); 540   5512 expired.push_back(w);
541   } 541   }
HITCBC 542   4627 t->might_have_pending_waits_.store( 542   5512 t->might_have_pending_waits_.store(
543   false, std::memory_order_relaxed); 543   false, std::memory_order_relaxed);
544   } 544   }
545   545  
HITCBC 546   315807 refresh_cached_nearest(); 546   366442 refresh_cached_nearest();
HITCBC 547   315807 } 547   366442 }
548   548  
HITCBC 549   315807 std::size_t count = 0; 549   366442 std::size_t count = 0;
HITCBC 550   320434 while (auto* w = expired.pop_front()) 550   371954 while (auto* w = expired.pop_front())
551   { 551   {
HITCBC 552   4627 sched_->post(&w->op_); 552   5512 sched_->post(&w->op_);
HITCBC 553   4627 ++count; 553   5512 ++count;
HITCBC 554   4627 } 554   5512 }
555   555  
HITCBC 556   315807 return count; 556   366442 return count;
557   } 557   }
558   558  
559   inline void 559   inline void
HITCBC 560   6083 timer_service::remove_timer_impl(timer::implementation& impl) 560   6976 timer_service::remove_timer_impl(timer::implementation& impl)
561   { 561   {
HITCBC 562   6083 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed); 562   6976 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed);
HITCBC 563   6083 if (index >= heap_.size()) 563   6976 if (index >= heap_.size())
MISUBC 564   ✗ return; // Not in heap 564   ✗ return; // Not in heap
565   565  
HITCBC 566   6083 if (index == heap_.size() - 1) 566   6976 if (index == heap_.size() - 1)
567   { 567   {
568   // Last element, just pop 568   // Last element, just pop
HITCBC 569   1709 impl.heap_index_.store( 569   1697 impl.heap_index_.store(
570   (std::numeric_limits<std::size_t>::max)(), 570   (std::numeric_limits<std::size_t>::max)(),
571   std::memory_order_relaxed); 571   std::memory_order_relaxed);
HITCBC 572   1709 heap_.pop_back(); 572   1697 heap_.pop_back();
573   } 573   }
574   else 574   else
575   { 575   {
576   // Swap with last and reheapify 576   // Swap with last and reheapify
HITCBC 577   4374 swap_heap(index, heap_.size() - 1); 577   5279 swap_heap(index, heap_.size() - 1);
HITCBC 578   4374 impl.heap_index_.store( 578   5279 impl.heap_index_.store(
579   (std::numeric_limits<std::size_t>::max)(), 579   (std::numeric_limits<std::size_t>::max)(),
580   std::memory_order_relaxed); 580   std::memory_order_relaxed);
HITCBC 581   4374 heap_.pop_back(); 581   5279 heap_.pop_back();
582   582  
HITCBC 583   4374 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_) 583   5279 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_)
MISUBC 584   ✗ up_heap(index); 584   ✗ up_heap(index);
585   else 585   else
HITCBC 586   4374 down_heap(index); 586   5279 down_heap(index);
587   } 587   }
588   } 588   }
589   589  
590   inline void 590   inline void
HITCBC 591   6111 timer_service::up_heap(std::size_t index) 591   7005 timer_service::up_heap(std::size_t index)
592   { 592   {
HITCBC 593   10378 while (index > 0) 593   12213 while (index > 0)
594   { 594   {
HITCBC 595   4521 std::size_t parent = (index - 1) / 2; 595   5370 std::size_t parent = (index - 1) / 2;
HITCBC 596   4521 if (!(heap_[index].time_ < heap_[parent].time_)) 596   5370 if (!(heap_[index].time_ < heap_[parent].time_))
HITCBC 597   254 break; 597   162 break;
HITCBC 598   4267 swap_heap(index, parent); 598   5208 swap_heap(index, parent);
HITCBC 599   4267 index = parent; 599   5208 index = parent;
600   } 600   }
HITCBC 601   6111 } 601   7005 }
602   602  
603   inline void 603   inline void
HITCBC 604   4374 timer_service::down_heap(std::size_t index) 604   5279 timer_service::down_heap(std::size_t index)
605   { 605   {
HITCBC 606   4374 std::size_t child = index * 2 + 1; 606   5279 std::size_t child = index * 2 + 1;
HITCBC 607   4546 while (child < heap_.size()) 607   5405 while (child < heap_.size())
608   { 608   {
HITCBC 609   174 std::size_t min_child = (child + 1 == heap_.size() || 609   150 std::size_t min_child = (child + 1 == heap_.size() ||
HITCBC 610   164 heap_[child].time_ < heap_[child + 1].time_) 610   122 heap_[child].time_ < heap_[child + 1].time_)
HITCBC 611   338 ? child 611   272 ? child
HITCBC 612   174 : child + 1; 612   150 : child + 1;
613   613  
HITCBC 614   174 if (heap_[index].time_ < heap_[min_child].time_) 614   150 if (heap_[index].time_ < heap_[min_child].time_)
HITCBC 615   2 break; 615   24 break;
616   616  
HITCBC 617   172 swap_heap(index, min_child); 617   126 swap_heap(index, min_child);
HITCBC 618   172 index = min_child; 618   126 index = min_child;
HITCBC 619   172 child = index * 2 + 1; 619   126 child = index * 2 + 1;
620   } 620   }
HITCBC 621   4374 } 621   5279 }
622   622  
623   inline void 623   inline void
HITCBC 624   8813 timer_service::swap_heap(std::size_t i1, std::size_t i2) 624   10613 timer_service::swap_heap(std::size_t i1, std::size_t i2)
625   { 625   {
HITCBC 626   8813 heap_entry tmp = heap_[i1]; 626   10613 heap_entry tmp = heap_[i1];
HITCBC 627   8813 heap_[i1] = heap_[i2]; 627   10613 heap_[i1] = heap_[i2];
HITCBC 628   8813 heap_[i2] = tmp; 628   10613 heap_[i2] = tmp;
HITCBC 629   8813 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed); 629   10613 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed);
HITCBC 630   8813 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed); 630   10613 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed);
HITCBC 631   8813 } 631   10613 }
632   632  
633   // waiter_node's completion_op and canceller members are defined in 633   // waiter_node's completion_op and canceller members are defined in
634   // timer.cpp alongside implementation::wait(), for the same reason 634   // timer.cpp alongside implementation::wait(), for the same reason
635   // wait() lives there (see below). 635   // wait() lives there (see below).
636   636  
637   // timer::implementation::wait() is defined in timer.cpp, not here. 637   // timer::implementation::wait() is defined in timer.cpp, not here.
638   // It must be a non-inline definition in a translation unit that is 638   // It must be a non-inline definition in a translation unit that is
639   // always pulled into the link whenever detail::timer is used (every 639   // always pulled into the link whenever detail::timer is used (every
640   // consumer needs timer's constructors from that same object file). 640   // consumer needs timer's constructors from that same object file).
641   // An inline definition in this header would only be emitted in 641   // An inline definition in this header would only be emitted in
642   // translation units that happen to also include this header, which 642   // translation units that happen to also include this header, which
643   // is not guaranteed for every caller of wait_awaitable::await_suspend 643   // is not guaranteed for every caller of wait_awaitable::await_suspend
644   // in timer.hpp (e.g. code that only reaches timer.hpp through 644   // in timer.hpp (e.g. code that only reaches timer.hpp through
645   // delay.hpp, without transitively including a scheduler header). 645   // delay.hpp, without transitively including a scheduler header).
646   646  
647   // Free functions 647   // Free functions
648   648  
649   inline timer_service& 649   inline timer_service&
HITCBC 650   1603 get_timer_service(capy::execution_context& ctx, scheduler& sched) 650   1790 get_timer_service(capy::execution_context& ctx, scheduler& sched)
651   { 651   {
HITCBC 652   1603 return ctx.make_service<timer_service>(sched); 652   1790 return ctx.make_service<timer_service>(sched);
653   } 653   }
654   654  
655   } // namespace boost::corosio::detail 655   } // namespace boost::corosio::detail
656   656  
657   #endif 657   #endif