. /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   1450 callback() = default; 100   1533 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   1450 callback(void* ctx, void (*fn)(void*)) noexcept : ctx_(ctx), fn_(fn) {} 103   1533 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   5961 void operator()() const 112   6076 void operator()() const
113   { 113   {
HITCBC 114   5961 if (fn_) 114   6076 if (fn_)
HITCBC 115   5961 fn_(ctx_); 115   6076 fn_(ctx_);
HITCBC 116   5961 } 116   6076 }
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   1450 inline timer_service(capy::execution_context&, scheduler& sched) 141   1533 inline timer_service(capy::execution_context&, scheduler& sched)
HITCBC 142   1450 : sched_(&sched) 142   1533 : sched_(&sched)
143   { 143   {
HITCBC 144   1450 } 144   1533 }
145   145  
146   /// Return the associated scheduler. 146   /// Return the associated scheduler.
HITCBC 147   12040 inline scheduler& get_scheduler() noexcept 147   12354 inline scheduler& get_scheduler() noexcept
148   { 148   {
HITCBC 149   12040 return *sched_; 149   12354 return *sched_;
150   } 150   }
151   151  
152   /// Destroy the timer service. 152   /// Destroy the timer service.
HITCBC 153   2900 ~timer_service() override = default; 153   3066 ~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   1450 inline void set_on_earliest_changed(callback cb) 159   1533 inline void set_on_earliest_changed(callback cb)
160   { 160   {
HITCBC 161   1450 on_earliest_changed_ = cb; 161   1533 on_earliest_changed_ = cb;
HITCBC 162   1450 } 162   1533 }
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   245689 inline time_point nearest_expiry() const noexcept 172   307048 inline time_point nearest_expiry() const noexcept
173   { 173   {
HITCBC 174   245689 auto ns = cached_nearest_ns_.load(std::memory_order_acquire); 174   307048 auto ns = cached_nearest_ns_.load(std::memory_order_acquire);
HITCBC 175   245689 return time_point(time_point::duration(ns)); 175   307048 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   273369 inline void refresh_cached_nearest() noexcept 203   332409 inline void refresh_cached_nearest() noexcept
204   { 204   {
HITCBC 205   273369 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)() 205   332409 auto ns = heap_.empty() ? (std::numeric_limits<std::int64_t>::max)()
HITCBC 206   270004 : heap_[0].time_.time_since_epoch().count(); 206   328979 : heap_[0].time_.time_since_epoch().count();
HITCBC 207   273369 cached_nearest_ns_.store(ns, std::memory_order_release); 207   332409 cached_nearest_ns_.store(ns, std::memory_order_release);
HITCBC 208   273369 } 208   332409 }
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   39 ~tl_cache_owner() 231   44 ~tl_cache_owner()
232   { 232   {
HITCBC 233   39 delete tl_cached_impl.get(); 233   44 delete tl_cached_impl.get();
HITCBC 234   39 tl_cached_impl.set(nullptr); 234   44 tl_cached_impl.set(nullptr);
HITCBC 235   39 } 235   44 }
236   }; 236   };
237   237  
238   inline void 238   inline void
HITCBC 239   6789 arm_tl_cache_cleanup() noexcept 239   6962 arm_tl_cache_cleanup() noexcept
240   { 240   {
HITCBC 241   6789 thread_local tl_cache_owner owner; 241   6962 thread_local tl_cache_owner owner;
242   (void)owner; 242   (void)owner;
HITCBC 243   6789 } 243   6962 }
244   244  
245   inline timer::implementation* 245   inline timer::implementation*
HITCBC 246   6885 try_pop_tl_cache(timer_service* svc) noexcept 246   7042 try_pop_tl_cache(timer_service* svc) noexcept
247   { 247   {
HITCBC 248   6885 auto* impl = tl_cached_impl.get(); 248   7042 auto* impl = tl_cached_impl.get();
HITCBC 249   6885 if (impl) 249   7042 if (impl)
250   { 250   {
HITCBC 251   6526 tl_cached_impl.set(nullptr); 251   6684 tl_cached_impl.set(nullptr);
HITCBC 252   6526 if (impl->svc_ == svc) 252   6684 if (impl->svc_ == svc)
HITCBC 253   6526 return impl; 253   6684 return impl;
254   // Stale impl from a destroyed service 254   // Stale impl from a destroyed service
MISUBC 255   ✗ delete impl; 255   ✗ delete impl;
256   } 256   }
HITCBC 257   359 return nullptr; 257   358 return nullptr;
258   } 258   }
259   259  
260   inline bool 260   inline bool
HITCBC 261   6857 try_push_tl_cache(timer::implementation* impl) noexcept 261   7014 try_push_tl_cache(timer::implementation* impl) noexcept
262   { 262   {
HITCBC 263   6857 if (!tl_cached_impl.get()) 263   7014 if (!tl_cached_impl.get())
264   { 264   {
HITCBC 265   6789 arm_tl_cache_cleanup(); 265   6962 arm_tl_cache_cleanup();
HITCBC 266   6789 tl_cached_impl.set(impl); 266   6962 tl_cached_impl.set(impl);
HITCBC 267   6789 return true; 267   6962 return true;
268   } 268   }
HITCBC 269   68 return false; 269   52 return false;
270   } 270   }
271   271  
272   inline void 272   inline void
HITCBC 273   1450 timer_service_invalidate_cache() noexcept 273   1533 timer_service_invalidate_cache() noexcept
274   { 274   {
HITCBC 275   1450 delete tl_cached_impl.get(); 275   1533 delete tl_cached_impl.get();
HITCBC 276   1450 tl_cached_impl.set(nullptr); 276   1533 tl_cached_impl.set(nullptr);
HITCBC 277   1450 } 277   1533 }
278   278  
279   // timer_service out-of-class member function definitions 279   // timer_service out-of-class member function definitions
280   280  
281   inline void 281   inline void
HITCBC 282   1450 timer_service::shutdown() 282   1533 timer_service::shutdown()
283   { 283   {
HITCBC 284   1450 timer_service_invalidate_cache(); 284   1533 timer_service_invalidate_cache();
HITCBC 285   1450 shutting_down_ = true; 285   1533 shutting_down_ = true;
286   286  
287   // Snapshot impls and detach them from the heap so that 287   // Snapshot impls and detach them from the heap so that
288   // coroutine-owned timer destructors (triggered by h.destroy() 288   // coroutine-owned timer destructors (triggered by h.destroy()
289   // below) cannot re-enter remove_timer_impl() and mutate the 289   // below) cannot re-enter remove_timer_impl() and mutate the
290   // vector during iteration. 290   // vector during iteration.
HITCBC 291   1450 std::vector<timer::implementation*> impls; 291   1533 std::vector<timer::implementation*> impls;
HITCBC 292   1450 impls.reserve(heap_.size()); 292   1533 impls.reserve(heap_.size());
HITCBC 293   1478 for (auto& entry : heap_) 293   1561 for (auto& entry : heap_)
294   { 294   {
HITCBC 295   28 entry.timer_->heap_index_.store( 295   28 entry.timer_->heap_index_.store(
296   (std::numeric_limits<std::size_t>::max)(), 296   (std::numeric_limits<std::size_t>::max)(),
297   std::memory_order_relaxed); 297   std::memory_order_relaxed);
HITCBC 298   28 impls.push_back(entry.timer_); 298   28 impls.push_back(entry.timer_);
299   } 299   }
HITCBC 300   1450 heap_.clear(); 300   1533 heap_.clear();
HITCBC 301   1450 cached_nearest_ns_.store( 301   1533 cached_nearest_ns_.store(
302   (std::numeric_limits<std::int64_t>::max)(), std::memory_order_release); 302   (std::numeric_limits<std::int64_t>::max)(), std::memory_order_release);
303   303  
304   // Cancel waiting timers. Each waiter called work_started() 304   // Cancel waiting timers. Each waiter called work_started()
305   // in implementation::wait(). On IOCP the scheduler shutdown 305   // in implementation::wait(). On IOCP the scheduler shutdown
306   // loop exits when outstanding_work_ reaches zero, so we must 306   // loop exits when outstanding_work_ reaches zero, so we must
307   // call work_finished() here to balance it. On other backends 307   // call work_finished() here to balance it. On other backends
308   // this is harmless. 308   // this is harmless.
HITCBC 309   1478 for (auto* impl : impls) 309   1561 for (auto* impl : impls)
310   { 310   {
HITCBC 311   28 if (auto* w = std::exchange(impl->waiter_, nullptr)) 311   28 if (auto* w = std::exchange(impl->waiter_, nullptr))
312   { 312   {
HITCBC 313   28 w->reset_stop_cb(); 313   28 w->reset_stop_cb();
HITCBC 314   28 auto h = std::exchange(w->h_, {}); 314   28 auto h = std::exchange(w->h_, {});
HITCBC 315   28 sched_->work_finished(); 315   28 sched_->work_finished();
316   // Destroying the frame also ends the node's storage 316   // Destroying the frame also ends the node's storage
HITCBC 317   28 if (h) 317   28 if (h)
HITCBC 318   28 h.destroy(); 318   28 h.destroy();
319   } 319   }
HITCBC 320   28 delete impl; 320   28 delete impl;
321   } 321   }
322   322  
323   // Delete free-listed impls 323   // Delete free-listed impls
HITCBC 324   1516 while (free_list_) 324   1583 while (free_list_)
325   { 325   {
HITCBC 326   66 auto* next = free_list_->next_free_; 326   50 auto* next = free_list_->next_free_;
HITCBC 327   66 delete free_list_; 327   50 delete free_list_;
HITCBC 328   66 free_list_ = next; 328   50 free_list_ = next;
329   } 329   }
HITCBC 330   1450 } 330   1533 }
331   331  
332   inline io_object::implementation* 332   inline io_object::implementation*
HITCBC 333   6885 timer_service::construct() 333   7042 timer_service::construct()
334   { 334   {
HITCBC 335   6885 timer::implementation* impl = try_pop_tl_cache(this); 335   7042 timer::implementation* impl = try_pop_tl_cache(this);
HITCBC 336   6885 if (impl) 336   7042 if (impl)
337   { 337   {
HITCBC 338   6526 impl->svc_ = this; 338   6684 impl->svc_ = this;
339   // Reset expiry_ too: a recycled impl must behave like a fresh 339   // Reset expiry_ too: a recycled impl must behave like a fresh
340   // one, whose default expiry reads as already elapsed 340   // one, whose default expiry reads as already elapsed
HITCBC 341   6526 impl->expiry_ = {}; 341   6684 impl->expiry_ = {};
HITCBC 342   6526 impl->heap_index_.store( 342   6684 impl->heap_index_.store(
343   (std::numeric_limits<std::size_t>::max)(), 343   (std::numeric_limits<std::size_t>::max)(),
344   std::memory_order_relaxed); 344   std::memory_order_relaxed);
HITCBC 345   6526 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 345   6684 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 346   6526 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr); 346   6684 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr);
HITCBC 347   6526 return impl; 347   6684 return impl;
348   } 348   }
349   349  
HITCBC 350   359 std::lock_guard lock(mutex_); 350   358 std::lock_guard lock(mutex_);
HITCBC 351   359 if (free_list_) 351   358 if (free_list_)
352   { 352   {
HITCBC 353   2 impl = free_list_; 353   2 impl = free_list_;
HITCBC 354   2 free_list_ = impl->next_free_; 354   2 free_list_ = impl->next_free_;
HITCBC 355   2 impl->next_free_ = nullptr; 355   2 impl->next_free_ = nullptr;
HITCBC 356   2 impl->svc_ = this; 356   2 impl->svc_ = this;
HITCBC 357   2 impl->expiry_ = {}; 357   2 impl->expiry_ = {};
HITCBC 358   2 impl->heap_index_.store( 358   2 impl->heap_index_.store(
359   (std::numeric_limits<std::size_t>::max)(), 359   (std::numeric_limits<std::size_t>::max)(),
360   std::memory_order_relaxed); 360   std::memory_order_relaxed);
HITCBC 361   2 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed); 361   2 impl->might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 362   2 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr); 362   2 BOOST_COROSIO_ASSERT(impl->waiter_ == nullptr);
363   } 363   }
364   else 364   else
365   { 365   {
HITCBC 366   357 impl = new timer::implementation(*this); 366   356 impl = new timer::implementation(*this);
367   } 367   }
HITCBC 368   359 return impl; 368   358 return impl;
HITCBC 369   359 } 369   358 }
370   370  
371   inline void 371   inline void
HITCBC 372   6885 timer_service::destroy(io_object::implementation* p) 372   7042 timer_service::destroy(io_object::implementation* p)
373   { 373   {
374   // During shutdown the drain loop owns every impl and deletes 374   // During shutdown the drain loop owns every impl and deletes
375   // them directly. A frame destroyed by that loop can unwind a 375   // them directly. A frame destroyed by that loop can unwind a
376   // handle whose impl was freed in an earlier iteration (a 376   // handle whose impl was freed in an earlier iteration (a
377   // timeout's parent frame owns the timeout timer while 377   // timeout's parent frame owns the timeout timer while
378   // suspended on the inner delay's timer), so bail out before 378   // suspended on the inner delay's timer), so bail out before
379   // even downcasting the pointer. 379   // even downcasting the pointer.
HITCBC 380   6885 if (shutting_down_) 380   7042 if (shutting_down_)
HITCBC 381   28 return; 381   28 return;
HITCBC 382   6857 destroy_impl(static_cast<timer::implementation&>(*p)); 382   7014 destroy_impl(static_cast<timer::implementation&>(*p));
383   } 383   }
384   384  
385   inline void 385   inline void
HITCBC 386   6857 timer_service::destroy_impl(timer::implementation& impl) 386   7014 timer_service::destroy_impl(timer::implementation& impl)
387   { 387   {
388   // During shutdown the impl is owned by the shutdown loop. 388   // During shutdown the impl is owned by the shutdown loop.
389   // Re-entering here (from a coroutine-owned timer destructor 389   // Re-entering here (from a coroutine-owned timer destructor
390   // triggered by h.destroy()) must not modify the heap or 390   // triggered by h.destroy()) must not modify the heap or
391   // recycle the impl — shutdown deletes it directly. 391   // recycle the impl — shutdown deletes it directly.
HITCBC 392   6857 if (shutting_down_) 392   7014 if (shutting_down_)
HITCBC 393   6789 return; 393   6962 return;
394   394  
HITCBC 395   6857 cancel_timer(impl); 395   7014 cancel_timer(impl);
396   396  
HITCBC 397   13714 if (impl.heap_index_.load(std::memory_order_relaxed) != 397   14028 if (impl.heap_index_.load(std::memory_order_relaxed) !=
HITCBC 398   6857 (std::numeric_limits<std::size_t>::max)()) 398   7014 (std::numeric_limits<std::size_t>::max)())
399   { 399   {
MISUBC 400   ✗ std::lock_guard lock(mutex_); 400   ✗ std::lock_guard lock(mutex_);
MISUBC 401   ✗ remove_timer_impl(impl); 401   ✗ remove_timer_impl(impl);
MISUBC 402   ✗ refresh_cached_nearest(); 402   ✗ refresh_cached_nearest();
MISUBC 403   ✗ } 403   ✗ }
404   404  
HITCBC 405   6857 if (try_push_tl_cache(&impl)) 405   7014 if (try_push_tl_cache(&impl))
HITCBC 406   6789 return; 406   6962 return;
407   407  
HITCBC 408   68 std::lock_guard lock(mutex_); 408   52 std::lock_guard lock(mutex_);
HITCBC 409   68 impl.next_free_ = free_list_; 409   52 impl.next_free_ = free_list_;
HITCBC 410   68 free_list_ = &impl; 410   52 free_list_ = &impl;
HITCBC 411   68 } 411   52 }
412   412  
413   inline void 413   inline void
HITCBC 414   6046 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w) 414   6203 timer_service::insert_waiter(timer::implementation& impl, waiter_node* w)
415   { 415   {
HITCBC 416   6046 bool notify = false; 416   6203 bool notify = false;
HITCBC 417   6046 bool lost_cancel = false; 417   6203 bool lost_cancel = false;
418   { 418   {
HITCBC 419   6046 std::lock_guard lock(mutex_); 419   6203 std::lock_guard lock(mutex_);
420   // Grow before publishing anything, so the push_back below 420   // Grow before publishing anything, so the push_back below
421   // cannot throw: a failure here leaves the waiter untouched, 421   // cannot throw: a failure here leaves the waiter untouched,
422   // the strong guarantee rearm_wait's recovery relies on. 422   // the strong guarantee rearm_wait's recovery relies on.
HITCBC 423   6046 if (impl.heap_index_.load(std::memory_order_relaxed) == 423   6203 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 424   12092 (std::numeric_limits<std::size_t>::max)() && 424   12406 (std::numeric_limits<std::size_t>::max)() &&
HITCBC 425   6046 heap_.size() == heap_.capacity()) 425   6203 heap_.size() == heap_.capacity())
HITCBC 426   264 heap_.reserve( 426   279 heap_.reserve(
HITCBC 427   264 heap_.capacity() == 0 ? 16 : 2 * heap_.capacity()); 427   279 heap_.capacity() == 0 ? 16 : 2 * heap_.capacity());
428   // Publish: from here the waiter is visible to the fire path and 428   // Publish: from here the waiter is visible to the fire path and
429   // to its own stop callback (impl_ non-null enables cancel_waiter). 429   // to its own stop callback (impl_ non-null enables cancel_waiter).
HITCBC 430   6046 w->impl_ = &impl; 430   6203 w->impl_ = &impl;
HITCBC 431   12092 if (impl.heap_index_.load(std::memory_order_relaxed) == 431   12406 if (impl.heap_index_.load(std::memory_order_relaxed) ==
HITCBC 432   6046 (std::numeric_limits<std::size_t>::max)()) 432   6203 (std::numeric_limits<std::size_t>::max)())
433   { 433   {
HITCBC 434   6046 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed); 434   6203 impl.heap_index_.store(heap_.size(), std::memory_order_relaxed);
HITCBC 435   6046 heap_.push_back({impl.expiry_, &impl}); 435   6203 heap_.push_back({impl.expiry_, &impl});
HITCBC 436   6046 up_heap(heap_.size() - 1); 436   6203 up_heap(heap_.size() - 1);
HITCBC 437   6046 notify = 437   6203 notify =
HITCBC 438   6046 (impl.heap_index_.load(std::memory_order_relaxed) == 0); 438   6203 (impl.heap_index_.load(std::memory_order_relaxed) == 0);
HITCBC 439   6046 refresh_cached_nearest(); 439   6203 refresh_cached_nearest();
440   } 440   }
HITCBC 441   6046 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr); 441   6203 BOOST_COROSIO_ASSERT(impl.waiter_ == nullptr);
HITCBC 442   6046 impl.waiter_ = w; 442   6203 impl.waiter_ = w;
443   443  
444   // Lost-cancel re-check: a stop requested after the canceller was 444   // Lost-cancel re-check: a stop requested after the canceller was
445   // armed in wait() but before this publication found impl_ null 445   // armed in wait() but before this publication found impl_ null
446   // and returned a no-op. Observe it now and undo the insertion. 446   // and returned a no-op. Observe it now and undo the insertion.
HITCBC 447   6046 if (w->token_->stop_requested()) 447   6203 if (w->token_->stop_requested())
448   { 448   {
HITCBC 449   3 w->impl_ = nullptr; 449   6 w->impl_ = nullptr;
HITCBC 450   3 impl.waiter_ = nullptr; 450   6 impl.waiter_ = nullptr;
HITCBC 451   3 remove_timer_impl(impl); 451   6 remove_timer_impl(impl);
HITCBC 452   3 impl.might_have_pending_waits_.store( 452   6 impl.might_have_pending_waits_.store(
453   false, std::memory_order_relaxed); 453   false, std::memory_order_relaxed);
HITCBC 454   3 refresh_cached_nearest(); 454   6 refresh_cached_nearest();
HITCBC 455   3 lost_cancel = true; 455   6 lost_cancel = true;
HITCBC 456   3 notify = false; // insertion undone; nearest unchanged 456   6 notify = false; // insertion undone; nearest unchanged
457   } 457   }
HITCBC 458   6046 } 458   6203 }
HITCBC 459   6046 if (notify) 459   6203 if (notify)
HITCBC 460   5961 on_earliest_changed_(); 460   6076 on_earliest_changed_();
HITCBC 461   6046 if (lost_cancel) 461   6203 if (lost_cancel)
462   { 462   {
HITCBC 463   3 w->ec_ = make_error_code(capy::error::canceled); 463   6 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 464   3 sched_->post(&w->op_); 464   6 sched_->post(&w->op_);
465   } 465   }
HITCBC 466   6046 } 466   6203 }
467   467  
468   inline void 468   inline void
HITCBC 469   6857 timer_service::cancel_timer(timer::implementation& impl) 469   7014 timer_service::cancel_timer(timer::implementation& impl)
470   { 470   {
HITCBC 471   6857 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed)) 471   7014 if (!impl.might_have_pending_waits_.load(std::memory_order_relaxed))
HITCBC 472   6855 return; 472   7012 return;
473   473  
474   // No unlocked already-done fast-out here: it would need the 474   // No unlocked already-done fast-out here: it would need the
475   // non-atomic waiter_ (a race with concurrent drains), and an 475   // non-atomic waiter_ (a race with concurrent drains), and an
476   // index-only check is lifetime-unsafe because npos is stored 476   // index-only check is lifetime-unsafe because npos is stored
477   // before the drain finishes touching the impl. A stale-true 477   // before the drain finishes touching the impl. A stale-true
478   // flag is rare with the stateless API; the locked path below 478   // flag is rare with the stateless API; the locked path below
479   // re-validates. 479   // re-validates.
480   480  
HITCBC 481   2 waiter_node* canceled = nullptr; 481   2 waiter_node* canceled = nullptr;
482   482  
483   { 483   {
HITCBC 484   2 std::lock_guard lock(mutex_); 484   2 std::lock_guard lock(mutex_);
HITCBC 485   2 remove_timer_impl(impl); 485   2 remove_timer_impl(impl);
HITCBC 486   2 canceled = std::exchange(impl.waiter_, nullptr); 486   2 canceled = std::exchange(impl.waiter_, nullptr);
HITCBC 487   2 if (canceled) 487   2 if (canceled)
HITCBC 488   2 canceled->impl_ = nullptr; 488   2 canceled->impl_ = nullptr;
489   // Store false as the final touch of the impl under the lock so 489   // Store false as the final touch of the impl under the lock so
490   // a pre-lock false-flag check trusts it unqualified. 490   // a pre-lock false-flag check trusts it unqualified.
HITCBC 491   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed); 491   2 impl.might_have_pending_waits_.store(false, std::memory_order_relaxed);
HITCBC 492   2 refresh_cached_nearest(); 492   2 refresh_cached_nearest();
HITCBC 493   2 } 493   2 }
494   494  
HITCBC 495   2 if (canceled) 495   2 if (canceled)
496   { 496   {
HITCBC 497   2 canceled->ec_ = make_error_code(capy::error::canceled); 497   2 canceled->ec_ = make_error_code(capy::error::canceled);
HITCBC 498   2 sched_->post(&canceled->op_); 498   2 sched_->post(&canceled->op_);
499   } 499   }
500   } 500   }
501   501  
502   inline void 502   inline void
HITCBC 503   1407 timer_service::cancel_waiter(waiter_node* w) 503   1404 timer_service::cancel_waiter(waiter_node* w)
504   { 504   {
505   { 505   {
HITCBC 506   1407 std::lock_guard lock(mutex_); 506   1404 std::lock_guard lock(mutex_);
507   // Already removed by another drain: cancel_timer, 507   // Already removed by another drain: cancel_timer,
508   // process_expired, or insert_waiter's lost-cancel recheck 508   // process_expired, or insert_waiter's lost-cancel recheck
HITCBC 509   1407 if (!w->impl_) 509   1404 if (!w->impl_)
HITCBC 510   3 return; 510   8 return;
HITCBC 511   1404 auto* impl = w->impl_; 511   1396 auto* impl = w->impl_;
HITCBC 512   1404 w->impl_ = nullptr; 512   1396 w->impl_ = nullptr;
HITCBC 513   1404 impl->waiter_ = nullptr; 513   1396 impl->waiter_ = nullptr;
HITCBC 514   1404 remove_timer_impl(*impl); 514   1396 remove_timer_impl(*impl);
HITCBC 515   1404 impl->might_have_pending_waits_.store( 515   1396 impl->might_have_pending_waits_.store(
516   false, std::memory_order_relaxed); 516   false, std::memory_order_relaxed);
HITCBC 517   1404 refresh_cached_nearest(); 517   1396 refresh_cached_nearest();
HITCBC 518   1407 } 518   1404 }
519   519  
HITCBC 520   1404 w->ec_ = make_error_code(capy::error::canceled); 520   1396 w->ec_ = make_error_code(capy::error::canceled);
HITCBC 521   1404 sched_->post(&w->op_); 521   1396 sched_->post(&w->op_);
522   } 522   }
523   523  
524   inline std::size_t 524   inline std::size_t
HITCBC 525   265914 timer_service::process_expired() 525   324802 timer_service::process_expired()
526   { 526   {
HITCBC 527   265914 intrusive_list<waiter_node> expired; 527   324802 intrusive_list<waiter_node> expired;
528   528  
529   { 529   {
HITCBC 530   265914 std::lock_guard lock(mutex_); 530   324802 std::lock_guard lock(mutex_);
HITCBC 531   265914 auto now = clock_type::now(); 531   324802 auto now = clock_type::now();
532   532  
HITCBC 533   270523 while (!heap_.empty() && heap_[0].time_ <= now) 533   329573 while (!heap_.empty() && heap_[0].time_ <= now)
534   { 534   {
HITCBC 535   4609 timer::implementation* t = heap_[0].timer_; 535   4771 timer::implementation* t = heap_[0].timer_;
HITCBC 536   4609 remove_timer_impl(*t); 536   4771 remove_timer_impl(*t);
HITCBC 537   4609 if (auto* w = std::exchange(t->waiter_, nullptr)) 537   4771 if (auto* w = std::exchange(t->waiter_, nullptr))
538   { 538   {
HITCBC 539   4609 w->impl_ = nullptr; 539   4771 w->impl_ = nullptr;
HITCBC 540   4609 w->ec_ = {}; 540   4771 w->ec_ = {};
HITCBC 541   4609 expired.push_back(w); 541   4771 expired.push_back(w);
542   } 542   }
HITCBC 543   4609 t->might_have_pending_waits_.store( 543   4771 t->might_have_pending_waits_.store(
544   false, std::memory_order_relaxed); 544   false, std::memory_order_relaxed);
545   } 545   }
546   546  
HITCBC 547   265914 refresh_cached_nearest(); 547   324802 refresh_cached_nearest();
HITCBC 548   265914 } 548   324802 }
549   549  
HITCBC 550   265914 std::size_t count = 0; 550   324802 std::size_t count = 0;
HITCBC 551   270523 while (auto* w = expired.pop_front()) 551   329573 while (auto* w = expired.pop_front())
552   { 552   {
HITCBC 553   4609 sched_->post(&w->op_); 553   4771 sched_->post(&w->op_);
HITCBC 554   4609 ++count; 554   4771 ++count;
HITCBC 555   4609 } 555   4771 }
556   556  
HITCBC 557   265914 return count; 557   324802 return count;
558   } 558   }
559   559  
560   inline void 560   inline void
HITCBC 561   6018 timer_service::remove_timer_impl(timer::implementation& impl) 561   6175 timer_service::remove_timer_impl(timer::implementation& impl)
562   { 562   {
HITCBC 563   6018 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed); 563   6175 std::size_t index = impl.heap_index_.load(std::memory_order_relaxed);
HITCBC 564   6018 if (index >= heap_.size()) 564   6175 if (index >= heap_.size())
MISUBC 565   ✗ return; // Not in heap 565   ✗ return; // Not in heap
566   566  
HITCBC 567   6018 if (index == heap_.size() - 1) 567   6175 if (index == heap_.size() - 1)
568   { 568   {
569   // Last element, just pop 569   // Last element, just pop
HITCBC 570   1680 impl.heap_index_.store( 570   1705 impl.heap_index_.store(
571   (std::numeric_limits<std::size_t>::max)(), 571   (std::numeric_limits<std::size_t>::max)(),
572   std::memory_order_relaxed); 572   std::memory_order_relaxed);
HITCBC 573   1680 heap_.pop_back(); 573   1705 heap_.pop_back();
574   } 574   }
575   else 575   else
576   { 576   {
577   // Swap with last and reheapify 577   // Swap with last and reheapify
HITCBC 578   4338 swap_heap(index, heap_.size() - 1); 578   4470 swap_heap(index, heap_.size() - 1);
HITCBC 579   4338 impl.heap_index_.store( 579   4470 impl.heap_index_.store(
580   (std::numeric_limits<std::size_t>::max)(), 580   (std::numeric_limits<std::size_t>::max)(),
581   std::memory_order_relaxed); 581   std::memory_order_relaxed);
HITCBC 582   4338 heap_.pop_back(); 582   4470 heap_.pop_back();
583   583  
HITCBC 584   4338 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_) 584   4470 if (index > 0 && heap_[index].time_ < heap_[(index - 1) / 2].time_)
MISUBC 585   ✗ up_heap(index); 585   ✗ up_heap(index);
586   else 586   else
HITCBC 587   4338 down_heap(index); 587   4470 down_heap(index);
588   } 588   }
589   } 589   }
590   590  
591   inline void 591   inline void
HITCBC 592   6046 timer_service::up_heap(std::size_t index) 592   6203 timer_service::up_heap(std::size_t index)
593   { 593   {
HITCBC 594   10342 while (index > 0) 594   10643 while (index > 0)
595   { 595   {
HITCBC 596   4378 std::size_t parent = (index - 1) / 2; 596   4561 std::size_t parent = (index - 1) / 2;
HITCBC 597   4378 if (!(heap_[index].time_ < heap_[parent].time_)) 597   4561 if (!(heap_[index].time_ < heap_[parent].time_))
HITCBC 598   82 break; 598   121 break;
HITCBC 599   4296 swap_heap(index, parent); 599   4440 swap_heap(index, parent);
HITCBC 600   4296 index = parent; 600   4440 index = parent;
601   } 601   }
HITCBC 602   6046 } 602   6203 }
603   603  
604   inline void 604   inline void
HITCBC 605   4338 timer_service::down_heap(std::size_t index) 605   4470 timer_service::down_heap(std::size_t index)
606   { 606   {
HITCBC 607   4338 std::size_t child = index * 2 + 1; 607   4470 std::size_t child = index * 2 + 1;
HITCBC 608   4347 while (child < heap_.size()) 608   4474 while (child < heap_.size())
609   { 609   {
HITCBC 610   14 std::size_t min_child = (child + 1 == heap_.size() || 610   6 std::size_t min_child = (child + 1 == heap_.size() ||
MISLBC 611   6 heap_[child].time_ < heap_[child + 1].time_) 611   ✗ heap_[child].time_ < heap_[child + 1].time_)
HITCBC 612   20 ? child 612   6 ? child
HITCBC 613   14 : child + 1; 613   6 : child + 1;
614   614  
HITCBC 615   14 if (heap_[index].time_ < heap_[min_child].time_) 615   6 if (heap_[index].time_ < heap_[min_child].time_)
HITCBC 616   5 break; 616   2 break;
617   617  
HITCBC 618   9 swap_heap(index, min_child); 618   4 swap_heap(index, min_child);
HITCBC 619   9 index = min_child; 619   4 index = min_child;
HITCBC 620   9 child = index * 2 + 1; 620   4 child = index * 2 + 1;
621   } 621   }
HITCBC 622   4338 } 622   4470 }
623   623  
624   inline void 624   inline void
HITCBC 625   8643 timer_service::swap_heap(std::size_t i1, std::size_t i2) 625   8914 timer_service::swap_heap(std::size_t i1, std::size_t i2)
626   { 626   {
HITCBC 627   8643 heap_entry tmp = heap_[i1]; 627   8914 heap_entry tmp = heap_[i1];
HITCBC 628   8643 heap_[i1] = heap_[i2]; 628   8914 heap_[i1] = heap_[i2];
HITCBC 629   8643 heap_[i2] = tmp; 629   8914 heap_[i2] = tmp;
HITCBC 630   8643 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed); 630   8914 heap_[i1].timer_->heap_index_.store(i1, std::memory_order_relaxed);
HITCBC 631   8643 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed); 631   8914 heap_[i2].timer_->heap_index_.store(i2, std::memory_order_relaxed);
HITCBC 632   8643 } 632   8914 }
633   633  
634   // waiter_node's completion_op and canceller members are defined in 634   // waiter_node's completion_op and canceller members are defined in
635   // timer.cpp alongside implementation::wait(), for the same reason 635   // timer.cpp alongside implementation::wait(), for the same reason
636   // wait() lives there (see below). 636   // wait() lives there (see below).
637   637  
638   // timer::implementation::wait() is defined in timer.cpp, not here. 638   // timer::implementation::wait() is defined in timer.cpp, not here.
639   // It must be a non-inline definition in a translation unit that is 639   // It must be a non-inline definition in a translation unit that is
640   // always pulled into the link whenever detail::timer is used (every 640   // always pulled into the link whenever detail::timer is used (every
641   // consumer needs timer's constructors from that same object file). 641   // consumer needs timer's constructors from that same object file).
642   // An inline definition in this header would only be emitted in 642   // An inline definition in this header would only be emitted in
643   // translation units that happen to also include this header, which 643   // translation units that happen to also include this header, which
644   // is not guaranteed for every caller of wait_awaitable::await_suspend 644   // is not guaranteed for every caller of wait_awaitable::await_suspend
645   // in timer.hpp (e.g. code that only reaches timer.hpp through 645   // in timer.hpp (e.g. code that only reaches timer.hpp through
646   // delay.hpp, without transitively including a scheduler header). 646   // delay.hpp, without transitively including a scheduler header).
647   647  
648   // Free functions 648   // Free functions
649   649  
650   inline timer_service& 650   inline timer_service&
HITCBC 651   1450 get_timer_service(capy::execution_context& ctx, scheduler& sched) 651   1533 get_timer_service(capy::execution_context& ctx, scheduler& sched)
652   { 652   {
HITCBC 653   1450 return ctx.make_service<timer_service>(sched); 653   1533 return ctx.make_service<timer_service>(sched);
654   } 654   }
655   655  
656   } // namespace boost::corosio::detail 656   } // namespace boost::corosio::detail
657   657  
658   #endif 658   #endif