. /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   2241 callback() = default; 100   2241 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   2241 callback(void* ctx, void (*fn)(void*)) noexcept : ctx_(ctx), fn_(fn) {} 103   2241 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   6680 void operator()() const 112   5331 void operator()() const
113   { 113   {
HITCBC 114   6680 if (fn_) 114   5331 if (fn_)
HITCBC 115   6680 fn_(ctx_); 115   5331 fn_(ctx_);
HITCBC 116   6680 } 116   5331 }
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   2241 inline timer_service(capy::execution_context&, scheduler& sched) 141   2241 inline timer_service(capy::execution_context&, scheduler& sched)
HITCBC 142   2241 : sched_(&sched) 142   2241 : sched_(&sched)
143   { 143   {
HITCBC 144   2241 } 144   2241 }
145   145  
146   /// Return the associated scheduler. 146   /// Return the associated scheduler.
HITCBC 147   28089 inline scheduler& get_scheduler() noexcept 147   24815 inline scheduler& get_scheduler() noexcept
148   { 148   {
HITCBC 149   28089 return *sched_; 149   24815 return *sched_;
150   } 150   }
151   151  
152   /// Destroy the timer service. 152   /// Destroy the timer service.
HITCBC 153   4482 ~timer_service() override = default; 153   4482 ~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   2241 inline void set_on_earliest_changed(callback cb) 159   2241 inline void set_on_earliest_changed(callback cb)
160   { 160   {
HITCBC 161   2241 on_earliest_changed_ = cb; 161   2241 on_earliest_changed_ = cb;
HITCBC 162   2241 } 162   2241 }
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   235187 inline time_point nearest_expiry() const noexcept 172   231302 inline time_point nearest_expiry() const noexcept
173   { 173   {
HITCBC 174   235187 auto ns = cached_nearest_ns_.load(std::memory_order_acquire); 174   231302 auto ns = cached_nearest_ns_.load(std::memory_order_acquire);
HITCBC 175   235187 return time_point(time_point::duration(ns)); 175   231302 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   274256 inline void refresh_cached_nearest() noexcept 203   270926 inline void refresh_cached_nearest() noexcept
204   { 204   {
HITCBC 205   274256 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)() 205   270926 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)()
HITCBC 206   268436 : heap_[0].time_.time_since_epoch().count(); 206   264909 : heap_[0].time_.time_since_epoch().count();
HITCBC 207   274256 cached_nearest_ns_.store(ns, std::memory_order_release); 207   270926 cached_nearest_ns_.store(ns, std::memory_order_release);
HITCBC 208   274256 } 208   270926 }
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   45 ~tl_cache_owner() 231   43 ~tl_cache_owner()
232   { 232   {
HITCBC 233   45 delete tl_cached_impl.get(); 233   43 delete tl_cached_impl.get();
HITCBC 234   45 tl_cached_impl.set(nullptr); 234   43 tl_cached_impl.set(nullptr);
HITCBC 235   45 } 235   43 }
236   }; 236   };
237   237  
238   inline void 238   inline void
HITCBC 239   13688 arm_tl_cache_cleanup() noexcept 239   12256 arm_tl_cache_cleanup() noexcept
240   { 240   {
HITCBC 241   13688 [[maybe_unused]] thread_local tl_cache_owner owner; 241   12256 [[maybe_unused]] thread_local tl_cache_owner owner;
HITCBC 242   13688 } 242   12256 }
243   243  
244   inline timer::implementation* 244   inline timer::implementation*
HITCBC 245   14912 try_pop_tl_cache(timer_service* svc) noexcept 245   13249 try_pop_tl_cache(timer_service* svc) noexcept
246   { 246   {
HITCBC 247   14912 auto* impl = tl_cached_impl.get(); 247   13249 auto* impl = tl_cached_impl.get();
HITCBC 248   14912 if (impl) 248   13249 if (impl)
249   { 249   {
HITCBC 250   13273 tl_cached_impl.set(nullptr); 250   11842 tl_cached_impl.set(nullptr);
HITCBC 251   13273 if (impl->svc_ == svc) 251   11842 if (impl->svc_ == svc)
HITCBC 252   13273 return impl; 252   11842 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   1639 return nullptr; 256   1407 return nullptr;
257   } 257   }
258   258  
259   inline bool 259   inline bool
HITCBC 260   14883 try_push_tl_cache(timer::implementation* impl) noexcept 260   13220 try_push_tl_cache(timer::implementation* impl) noexcept
261   { 261   {
HITCBC 262   14883 if (!tl_cached_impl.get()) 262   13220 if (!tl_cached_impl.get())
263   { 263   {
HITCBC 264   13688 arm_tl_cache_cleanup(); 264   12256 arm_tl_cache_cleanup();
HITCBC 265   13688 tl_cached_impl.set(impl); 265   12256 tl_cached_impl.set(impl);
HITCBC 266   13688 return true; 266   12256 return true;
267   } 267   }
HITCBC 268   1195 return false; 268   964 return false;
269   } 269   }
270   270  
271   inline void 271   inline void
HITCBC 272   2241 timer_service_invalidate_cache() noexcept 272   2241 timer_service_invalidate_cache() noexcept
273   { 273   {
HITCBC 274   2241 delete tl_cached_impl.get(); 274   2241 delete tl_cached_impl.get();
HITCBC 275   2241 tl_cached_impl.set(nullptr); 275   2241 tl_cached_impl.set(nullptr);
HITCBC 276   2241 } 276   2241 }
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   2241 timer_service::shutdown() 281   2241 timer_service::shutdown()
282   { 282   {
HITCBC 283   2241 timer_service_invalidate_cache(); 283   2241 timer_service_invalidate_cache();
HITCBC 284   2241 shutting_down_ = true; 284   2241 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   2241 std::vector<timer::implementation*> impls; 290   2241 std::vector<timer::implementation*> impls;
HITCBC 291   2241 impls.reserve(heap_.size()); 291   2241 impls.reserve(heap_.size());
HITCBC 292   2270 for (auto& entry : heap_) 292   2270 for (auto& entry : heap_)
293   { 293   {
HITCBC 294   29 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   29 impls.push_back(entry.timer_); 297   29 impls.push_back(entry.timer_);
298   } 298   }
HITCBC 299   2241 heap_.clear(); 299   2241 heap_.clear();
HITCBC 300   2241 cached_nearest_ns_.store( 300   2241 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   2270 for (auto* impl : impls) 308   2270 for (auto* impl : impls)
309   { 309   {
HITCBC 310   29 if (auto* w = std::exchange(impl->waiter_, nullptr)) 310   29 if (auto* w = std::exchange(impl->waiter_, nullptr))
311   { 311   {
HITCBC 312   29 w->reset_stop_cb(); 312   29 w->reset_stop_cb();
HITCBC 313   29 auto h = std::exchange(w->h_, {}); 313   29 auto h = std::exchange(w->h_, {});
HITCBC 314   29 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   29 if (h) 316   29 if (h)
HITCBC 317   29 h.destroy(); 317   29 h.destroy();
318   } 318   }
HITCBC 319   29 delete impl; 319   29 delete impl;
320   } 320   }
321   321  
322   // Delete free-listed impls 322   // Delete free-listed impls
HITCBC 323   3434 while (free_list_) 323   3203 while (free_list_)
324   { 324   {
HITCBC 325   1193 auto* next = free_list_->next_free_; 325   962 auto* next = free_list_->next_free_;
HITCBC 326   1193 delete free_list_; 326   962 delete free_list_;
HITCBC 327   1193 free_list_ = next; 327   962 free_list_ = next;
328   } 328   }
HITCBC 329   2241 } 329   2241 }
330   330  
331   inline io_object::implementation* 331   inline io_object::implementation*
HITCBC 332   14912 timer_service::construct() 332   13249 timer_service::construct()
333   { 333   {
HITCBC 334   14912 timer::implementation* impl = try_pop_tl_cache(this); 334   13249 timer::implementation* impl = try_pop_tl_cache(this);
HITCBC 335   14912 if (impl) 335   13249 if (impl)
336   { 336   {
HITCBC 337   13273 impl->svc_ = this; 337   11842 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   13273 impl->expiry_ = {}; 340   11842 impl->expiry_ = {};
HITCBC 341   13273 impl->heap_index_.store( 341   11842 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   13273 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 344   11842 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 345   13273 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr); 345   11842 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr);
HITCBC 346   13273 return impl; 346   11842 return impl;
347   } 347   }
348   348  
HITCBC 349   1639 std::lock_guard lock(mutex_); 349   1407 std::lock_guard lock(mutex_);
HITCBC 350   1639 if (free_list_) 350   1407 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   1637 impl = new timer::implementation(*this); 365   1405 impl = new timer::implementation(*this);
366   } 366   }
HITCBC 367   1639 return impl; 367   1407 return impl;
HITCBC 368   1639 } 368   1407 }
369   369  
370   inline void 370   inline void
HITCBC 371   14912 timer_service::destroy(io_object::implementation* p) 371   13249 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   14912 if (shutting_down_) 379   13249 if (shutting_down_)
HITCBC 380   29 return; 380   29 return;
HITCBC 381   14883 destroy_impl(static_cast<timer::implementation&>(*p)); 381   13220 destroy_impl(static_cast<timer::implementation&>(*p));
382   } 382   }
383   383  
384   inline void 384   inline void
HITCBC 385   14883 timer_service::destroy_impl(timer::implementation& impl) 385   13220 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   14883 if (shutting_down_) 391   13220 if (shutting_down_)
HITCBC 392   13688 return; 392   12256 return;
393   393  
HITCBC 394   14883 cancel_timer(impl); 394   13220 cancel_timer(impl);
395   395  
HITCBC 396   29766 if (impl.heap_index_.load(std::memory_order_relaxed) != 396   26440 if (impl.heap_index_.load(std::memory_order_relaxed) !=
HITCBC 397   14883 (std::numeric_limits<std::size_t>::max)()) 397   13220 (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   14883 if (try_push_tl_cache(&impl)) 404   13220 if (try_push_tl_cache(&impl))
HITCBC 405   13688 return; 405   12256 return;
406   406  
HITCBC 407   1195 std::lock_guard lock(mutex_); 407   964 std::lock_guard lock(mutex_);
HITCBC 408   1195 impl.next_free_ = free_list_; 408   964 impl.next_free_ = free_list_;
HITCBC 409   1195 free_list_ = &impl; 409   964 free_list_ = &impl;
HITCBC 410   1195 } 410   964 }
411   411  
412   inline void 412   inline void
HITCBC 413   17959 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w) 413   16811 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w)
414   { 414   {
HITCBC 415   17959 bool notify = false; 415   16811 bool notify = false;
HITCBC 416   17959 bool lost_cancel = false; 416   16811 bool lost_cancel = false;
417   { 417   {
HITCBC 418   17959 std::lock_guard lock(mutex_); 418   16811 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   17959 if (impl.heap_index_.load(std::memory_order_relaxed) == 422   16811 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 423   35918 (std::numeric_limits<std::size_t>::max)() && 423   33622 (std::numeric_limits<std::size_t>::max)() &&
HITCBC 424   17959 heap_.size() == heap_.capacity()) 424   16811 heap_.size() == heap_.capacity())
HITCBC 425   427 heap_.reserve(heap_.capacity() == 0 ? 16 : 2 * heap_.capacity()); 425   424 heap_.reserve(heap_.capacity() == 0 ? 16 : 2 * heap_.capacity());
426   // Publish: from here the waiter is visible to the fire path and 426   // Publish: from here the waiter is visible to the fire path and
427   // to its own stop callback (impl_ non-null enables cancel_waiter). 427   // to its own stop callback (impl_ non-null enables cancel_waiter).
HITCBC 428   17959 w->impl_ = &impl; 428   16811 w->impl_ = &impl;
HITCBC 429   35918 if (impl.heap_index_.load(std::memory_order_relaxed) == 429   33622 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 430   17959 (std::numeric_limits<std::size_t>::max)()) 430   16811 (std::numeric_limits<std::size_t>::max)())
431   { 431   {
HITCBC 432   17959 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed); 432   16811 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed);
HITCBC 433   17959 heap_.push_back({impl.expiry_, &impl}); 433   16811 heap_.push_back({impl.expiry_, &impl});
HITCBC 434   17959 up_heap(heap_.size() - 1); 434   16811 up_heap(heap_.size() - 1);
HITCBC 435   17959 notify = (impl.heap_index_.load(std::memory_order_relaxed) == 0); 435   16811 notify = (impl.heap_index_.load(std::memory_order_relaxed) == 0);
HITCBC 436   17959 refresh_cached_nearest(); 436   16811 refresh_cached_nearest();
437   } 437   }
HITCBC 438   17959 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr); 438   16811 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr);
HITCBC 439   17959 impl.waiter_ = w; 439   16811 impl.waiter_ = w;
440   440  
441   // Lost-cancel re-check: a stop requested after the canceller was 441   // Lost-cancel re-check: a stop requested after the canceller was
442   // armed in wait() but before this publication found impl_ null 442   // armed in wait() but before this publication found impl_ null
443   // and returned a no-op. Observe it now and undo the insertion. 443   // and returned a no-op. Observe it now and undo the insertion.
HITCBC 444   17959 if (w->token_->stop_requested()) 444   16811 if (w->token_->stop_requested())
445   { 445   {
HITCBC 446   6 w->impl_ = nullptr; 446   1 w->impl_ = nullptr;
HITCBC 447   6 impl.waiter_ = nullptr; 447   1 impl.waiter_ = nullptr;
HITCBC 448   6 remove_timer_impl(impl); 448   1 remove_timer_impl(impl);
HITCBC 449   6 impl.might_have_pending_waits_.store( 449   1 impl.might_have_pending_waits_.store(
450   false, std::memory_order_relaxed); 450   false, std::memory_order_relaxed);
HITCBC 451   6 refresh_cached_nearest(); 451   1 refresh_cached_nearest();
HITCBC 452   6 lost_cancel = true; 452   1 lost_cancel = true;
HITCBC 453   6 notify = false; // insertion undone; nearest unchanged 453   1 notify = false; // insertion undone; nearest unchanged
454   } 454   }
HITCBC 455   17959 } 455   16811 }
HITCBC 456   17959 if (notify) 456   16811 if (notify)
HITCBC 457   6680 on_earliest_changed_(); 457   5331 on_earliest_changed_();
HITCBC 458   17959 if (lost_cancel) 458   16811 if (lost_cancel)
459   { 459   {
HITCBC 460   6 w->ec_ = make_error_code(capy::error::canceled); 460   1 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 461   6 sched_->post(&w->op_); 461   1 sched_->post(&w->op_);
462   } 462   }
HITCBC 463   17959 } 463   16811 }
464   464  
465   inline void 465   inline void
HITCBC 466   14883 timer_service::cancel_timer(timer::implementation& impl) 466   13220 timer_service::cancel_timer(timer::implementation& impl)
467   { 467   {
HITCBC 468   14883 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed)) 468   13220 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed))
HITCBC 469   14881 return; 469   13218 return;
470   470  
471   // No unlocked already-done fast-out here: it would need the 471   // No unlocked already-done fast-out here: it would need the
472   // non-atomic waiter_ (a race with concurrent drains), and an 472   // non-atomic waiter_ (a race with concurrent drains), and an
473   // index-only check is lifetime-unsafe because npos is stored 473   // index-only check is lifetime-unsafe because npos is stored
474   // before the drain finishes touching the impl. A stale-true 474   // before the drain finishes touching the impl. A stale-true
475   // flag is rare with the stateless API; the locked path below 475   // flag is rare with the stateless API; the locked path below
476   // re-validates. 476   // re-validates.
477   477  
HITCBC 478   2 waiter_node* canceled = nullptr; 478   2 waiter_node* canceled = nullptr;
479   479  
480   { 480   {
HITCBC 481   2 std::lock_guard lock(mutex_); 481   2 std::lock_guard lock(mutex_);
HITCBC 482   2 remove_timer_impl(impl); 482   2 remove_timer_impl(impl);
HITCBC 483   2 canceled = std::exchange(impl.waiter_, nullptr); 483   2 canceled = std::exchange(impl.waiter_, nullptr);
HITCBC 484   2 if (canceled) 484   2 if (canceled)
HITCBC 485   2 canceled->impl_ = nullptr; 485   2 canceled->impl_ = nullptr;
486   // Store false as the final touch of the impl under the lock so 486   // Store false as the final touch of the impl under the lock so
487   // a pre-lock false-flag check trusts it unqualified. 487   // a pre-lock false-flag check trusts it unqualified.
HITCBC 488   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed); 488   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 489   2 refresh_cached_nearest(); 489   2 refresh_cached_nearest();
HITCBC 490   2 } 490   2 }
491   491  
HITCBC 492   2 if (canceled) 492   2 if (canceled)
493   { 493   {
HITCBC 494   2 canceled->ec_ = make_error_code(capy::error::canceled); 494   2 canceled->ec_ = make_error_code(capy::error::canceled);
HITCBC 495   2 sched_->post(&canceled->op_); 495   2 sched_->post(&canceled->op_);
496   } 496   }
497   } 497   }
498   498  
499   inline void 499   inline void
HITCBC 500   1641 timer_service::cancel_waiter(waiter_node* w) 500   1554 timer_service::cancel_waiter(waiter_node* w)
501   { 501   {
502   { 502   {
HITCBC 503   1641 std::lock_guard lock(mutex_); 503   1554 std::lock_guard lock(mutex_);
504   // Already removed by another drain: cancel_timer, 504   // Already removed by another drain: cancel_timer,
505   // process_expired, or insert_waiter's lost-cancel recheck 505   // process_expired, or insert_waiter's lost-cancel recheck
HITCBC 506   1641 if (!w->impl_) 506   1554 if (!w->impl_)
HITCBC 507   49 return; 507   2 return;
HITCBC 508   1592 auto* impl = w->impl_; 508   1552 auto* impl = w->impl_;
HITCBC 509   1592 w->impl_ = nullptr; 509   1552 w->impl_ = nullptr;
HITCBC 510   1592 impl->waiter_ = nullptr; 510   1552 impl->waiter_ = nullptr;
HITCBC 511   1592 remove_timer_impl(*impl); 511   1552 remove_timer_impl(*impl);
HITCBC 512   1592 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 512   1552 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 513   1592 refresh_cached_nearest(); 513   1552 refresh_cached_nearest();
HITCBC 514   1641 } 514   1554 }
515   515  
HITCBC 516   1592 w->ec_ = make_error_code(capy::error::canceled); 516   1552 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 517   1592 sched_->post(&w->op_); 517   1552 sched_->post(&w->op_);
518   } 518   }
519   519  
520   inline std::size_t 520   inline std::size_t
HITCBC 521   254697 timer_service::process_expired() 521   252560 timer_service::process_expired()
522   { 522   {
HITCBC 523   254697 intrusive_list<waiter_node> expired; 523   252560 intrusive_list<waiter_node> expired;
524   524  
525   { 525   {
HITCBC 526   254697 std::lock_guard lock(mutex_); 526   252560 std::lock_guard lock(mutex_);
HITCBC 527   254697 auto now = clock_type::now(); 527   252560 auto now = clock_type::now();
528   528  
HITCBC 529   271027 while (!heap_.empty() && heap_[0].time_ <= now) 529   267787 while (!heap_.empty() && heap_[0].time_ <= now)
530   { 530   {
HITCBC 531   16330 timer::implementation* t = heap_[0].timer_; 531   15227 timer::implementation* t = heap_[0].timer_;
HITCBC 532   16330 remove_timer_impl(*t); 532   15227 remove_timer_impl(*t);
HITCBC 533   16330 if (auto* w = std::exchange(t->waiter_, nullptr)) 533   15227 if (auto* w = std::exchange(t->waiter_, nullptr))
534   { 534   {
HITCBC 535   16330 w->impl_ = nullptr; 535   15227 w->impl_ = nullptr;
HITCBC 536   16330 w->ec_ = {}; 536   15227 w->ec_ = {};
HITCBC 537   16330 expired.push_back(w); 537   15227 expired.push_back(w);
538   } 538   }
HITCBC 539   16330 t->might_have_pending_waits_.store( 539   15227 t->might_have_pending_waits_.store(
540   false, std::memory_order_relaxed); 540   false, std::memory_order_relaxed);
541   } 541   }
542   542  
HITCBC 543   254697 refresh_cached_nearest(); 543   252560 refresh_cached_nearest();
HITCBC 544   254697 } 544   252560 }
545   545  
HITCBC 546   254697 std::size_t count = 0; 546   252560 std::size_t count = 0;
HITCBC 547   271027 while (auto* w = expired.pop_front()) 547   267787 while (auto* w = expired.pop_front())
548   { 548   {
HITCBC 549   16330 sched_->post(&w->op_); 549   15227 sched_->post(&w->op_);
HITCBC 550   16330 ++count; 550   15227 ++count;
HITCBC 551   16330 } 551   15227 }
552   552  
HITCBC 553   254697 return count; 553   252560 return count;
554   } 554   }
555   555  
556   inline void 556   inline void
HITCBC 557   17930 timer_service::remove_timer_impl(timer::implementation& impl) 557   16782 timer_service::remove_timer_impl(timer::implementation& impl)
558   { 558   {
HITCBC 559   17930 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed); 559   16782 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed);
HITCBC 560   17930 if (index >= heap_.size()) 560   16782 if (index >= heap_.size())
MISUBC 561   ✗ return; // Not in heap 561   ✗ return; // Not in heap
562   562  
HITCBC 563   17930 if (index == heap_.size() - 1) 563   16782 if (index == heap_.size() - 1)
564   { 564   {
565   // Last element, just pop 565   // Last element, just pop
HITCBC 566   2442 impl.heap_index_.store( 566   2646 impl.heap_index_.store(
567   (std::numeric_limits<std::size_t>::max)(), 567   (std::numeric_limits<std::size_t>::max)(),
568   std::memory_order_relaxed); 568   std::memory_order_relaxed);
HITCBC 569   2442 heap_.pop_back(); 569   2646 heap_.pop_back();
570   } 570   }
571   else 571   else
572   { 572   {
573   // Swap with last and reheapify 573   // Swap with last and reheapify
HITCBC 574   15488 swap_heap(index, heap_.size() - 1); 574   14136 swap_heap(index, heap_.size() - 1);
HITCBC 575   15488 impl.heap_index_.store( 575   14136 impl.heap_index_.store(
576   (std::numeric_limits<std::size_t>::max)(), 576   (std::numeric_limits<std::size_t>::max)(),
577   std::memory_order_relaxed); 577   std::memory_order_relaxed);
HITCBC 578   15488 heap_.pop_back(); 578   14136 heap_.pop_back();
579   579  
HITCBC 580   15488 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_) 580   14136 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_)
HITGBC 581   ✗ up_heap(index); 581   1 up_heap(index);
582   else 582   else
HITCBC 583   15488 down_heap(index); 583   14135 down_heap(index);
584   } 584   }
585   } 585   }
586   586  
587   inline void 587   inline void
HITCBC 588   17959 timer_service::up_heap(std::size_t index) 588   16812 timer_service::up_heap(std::size_t index)
589   { 589   {
HITCBC 590   24863 while (index > 0) 590   21872 while (index > 0)
591   { 591   {
HITCBC 592   18178 std::size_t parent = (index - 1) / 2; 592   16540 std::size_t parent = (index - 1) / 2;
HITCBC 593   18178 if (!(heap_[index].time_ < heap_[parent].time_)) 593   16540 if (!(heap_[index].time_ < heap_[parent].time_))
HITCBC 594   11274 break; 594   11480 break;
HITCBC 595   6904 swap_heap(index, parent); 595   5060 swap_heap(index, parent);
HITCBC 596   6904 index = parent; 596   5060 index = parent;
597   } 597   }
HITCBC 598   17959 } 598   16812 }
599   599  
600   inline void 600   inline void
HITCBC 601   15488 timer_service::down_heap(std::size_t index) 601   14135 timer_service::down_heap(std::size_t index)
602   { 602   {
HITCBC 603   15488 std::size_t child = index * 2 + 1; 603   14135 std::size_t child = index * 2 + 1;
HITCBC 604   33396 while (child < heap_.size()) 604   31780 while (child < heap_.size())
605   { 605   {
HITCBC 606   20089 std::size_t min_child = (child + 1 == heap_.size() || 606   19546 std::size_t min_child = (child + 1 == heap_.size() ||
HITCBC 607   16275 heap_[child].time_ < heap_[child + 1].time_) 607   15944 heap_[child].time_ < heap_[child + 1].time_)
HITCBC 608   36364 ? child 608   35490 ? child
HITCBC 609   20089 : child + 1; 609   19546 : child + 1;
610   610  
HITCBC 611   20089 if (heap_[index].time_ < heap_[min_child].time_) 611   19546 if (heap_[index].time_ < heap_[min_child].time_)
HITCBC 612   2181 break; 612   1901 break;
613   613  
HITCBC 614   17908 swap_heap(index, min_child); 614   17645 swap_heap(index, min_child);
HITCBC 615   17908 index = min_child; 615   17645 index = min_child;
HITCBC 616   17908 child = index * 2 + 1; 616   17645 child = index * 2 + 1;
617   } 617   }
HITCBC 618   15488 } 618   14135 }
619   619  
620   inline void 620   inline void
HITCBC 621   40300 timer_service::swap_heap(std::size_t i1, std::size_t i2) 621   36841 timer_service::swap_heap(std::size_t i1, std::size_t i2)
622   { 622   {
HITCBC 623   40300 heap_entry tmp = heap_[i1]; 623   36841 heap_entry tmp = heap_[i1];
HITCBC 624   40300 heap_[i1] = heap_[i2]; 624   36841 heap_[i1] = heap_[i2];
HITCBC 625   40300 heap_[i2] = tmp; 625   36841 heap_[i2] = tmp;
HITCBC 626   40300 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed); 626   36841 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed);
HITCBC 627   40300 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed); 627   36841 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed);
HITCBC 628   40300 } 628   36841 }
629   629  
630   // waiter_node's completion_op and canceller members are defined in 630   // waiter_node's completion_op and canceller members are defined in
631   // timer.cpp alongside implementation::wait(), for the same reason 631   // timer.cpp alongside implementation::wait(), for the same reason
632   // wait() lives there (see below). 632   // wait() lives there (see below).
633   633  
634   // timer::implementation::wait() is defined in timer.cpp, not here. 634   // timer::implementation::wait() is defined in timer.cpp, not here.
635   // It must be a non-inline definition in a translation unit that is 635   // It must be a non-inline definition in a translation unit that is
636   // always pulled into the link whenever detail::timer is used (every 636   // always pulled into the link whenever detail::timer is used (every
637   // consumer needs timer's constructors from that same object file). 637   // consumer needs timer's constructors from that same object file).
638   // An inline definition in this header would only be emitted in 638   // An inline definition in this header would only be emitted in
639   // translation units that happen to also include this header, which 639   // translation units that happen to also include this header, which
640   // is not guaranteed for every caller of wait_awaitable::await_suspend 640   // is not guaranteed for every caller of wait_awaitable::await_suspend
641   // in timer.hpp (e.g. code that only reaches timer.hpp through 641   // in timer.hpp (e.g. code that only reaches timer.hpp through
642   // delay.hpp, without transitively including a scheduler header). 642   // delay.hpp, without transitively including a scheduler header).
643   643  
644   // Free functions 644   // Free functions
645   645  
646   inline timer_service& 646   inline timer_service&
HITCBC 647   2241 get_timer_service(capy::execution_context& ctx, scheduler& sched) 647   2241 get_timer_service(capy::execution_context& ctx, scheduler& sched)
648   { 648   {
HITCBC 649   2241 return ctx.make_service<timer_service>(sched); 649   2241 return ctx.make_service<timer_service>(sched);
650   } 650   }
651   651  
652   } // namespace boost::corosio::detail 652   } // namespace boost::corosio::detail
653   653  
654   #endif 654   #endif