summaryrefslogtreecommitdiff
path: root/boost/asio/detail/impl/win_iocp_io_context.ipp
blob: 9071836aa9e4d993b97840ae33cabc2152ed6a26 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
//
// detail/impl/win_iocp_io_context.ipp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2017 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP
#define BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP

#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)

#include <boost/asio/detail/config.hpp>

#if defined(BOOST_ASIO_HAS_IOCP)

#include <boost/asio/error.hpp>
#include <boost/asio/detail/cstdint.hpp>
#include <boost/asio/detail/handler_alloc_helpers.hpp>
#include <boost/asio/detail/handler_invoke_helpers.hpp>
#include <boost/asio/detail/limits.hpp>
#include <boost/asio/detail/throw_error.hpp>
#include <boost/asio/detail/win_iocp_io_context.hpp>

#include <boost/asio/detail/push_options.hpp>

namespace boost {
namespace asio {
namespace detail {

struct win_iocp_io_context::work_finished_on_block_exit
{
  ~work_finished_on_block_exit()
  {
    io_context_->work_finished();
  }

  win_iocp_io_context* io_context_;
};

struct win_iocp_io_context::timer_thread_function
{
  void operator()()
  {
    while (::InterlockedExchangeAdd(&io_context_->shutdown_, 0) == 0)
    {
      if (::WaitForSingleObject(io_context_->waitable_timer_.handle,
            INFINITE) == WAIT_OBJECT_0)
      {
        ::InterlockedExchange(&io_context_->dispatch_required_, 1);
        ::PostQueuedCompletionStatus(io_context_->iocp_.handle,
            0, wake_for_dispatch, 0);
      }
    }
  }

  win_iocp_io_context* io_context_;
};

win_iocp_io_context::win_iocp_io_context(
    boost::asio::execution_context& ctx, int concurrency_hint)
  : execution_context_service_base<win_iocp_io_context>(ctx),
    iocp_(),
    outstanding_work_(0),
    stopped_(0),
    stop_event_posted_(0),
    shutdown_(0),
    gqcs_timeout_(get_gqcs_timeout()),
    dispatch_required_(0),
    concurrency_hint_(concurrency_hint)
{
  BOOST_ASIO_HANDLER_TRACKING_INIT;

  iocp_.handle = ::CreateIoCompletionPort(INVALID_HANDLE_VALUE, 0, 0,
      static_cast<DWORD>(concurrency_hint >= 0 ? concurrency_hint : DWORD(~0)));
  if (!iocp_.handle)
  {
    DWORD last_error = ::GetLastError();
    boost::system::error_code ec(last_error,
        boost::asio::error::get_system_category());
    boost::asio::detail::throw_error(ec, "iocp");
  }
}

void win_iocp_io_context::shutdown()
{
  ::InterlockedExchange(&shutdown_, 1);

  if (timer_thread_.get())
  {
    LARGE_INTEGER timeout;
    timeout.QuadPart = 1;
    ::SetWaitableTimer(waitable_timer_.handle, &timeout, 1, 0, 0, FALSE);
  }

  while (::InterlockedExchangeAdd(&outstanding_work_, 0) > 0)
  {
    op_queue<win_iocp_operation> ops;
    timer_queues_.get_all_timers(ops);
    ops.push(completed_ops_);
    if (!ops.empty())
    {
      while (win_iocp_operation* op = ops.front())
      {
        ops.pop();
        ::InterlockedDecrement(&outstanding_work_);
        op->destroy();
      }
    }
    else
    {
      DWORD bytes_transferred = 0;
      dword_ptr_t completion_key = 0;
      LPOVERLAPPED overlapped = 0;
      ::GetQueuedCompletionStatus(iocp_.handle, &bytes_transferred,
          &completion_key, &overlapped, gqcs_timeout_);
      if (overlapped)
      {
        ::InterlockedDecrement(&outstanding_work_);
        static_cast<win_iocp_operation*>(overlapped)->destroy();
      }
    }
  }

  if (timer_thread_.get())
    timer_thread_->join();
}

boost::system::error_code win_iocp_io_context::register_handle(
    HANDLE handle, boost::system::error_code& ec)
{
  if (::CreateIoCompletionPort(handle, iocp_.handle, 0, 0) == 0)
  {
    DWORD last_error = ::GetLastError();
    ec = boost::system::error_code(last_error,
        boost::asio::error::get_system_category());
  }
  else
  {
    ec = boost::system::error_code();
  }
  return ec;
}

size_t win_iocp_io_context::run(boost::system::error_code& ec)
{
  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
  {
    stop();
    ec = boost::system::error_code();
    return 0;
  }

  win_iocp_thread_info this_thread;
  thread_call_stack::context ctx(this, this_thread);

  size_t n = 0;
  while (do_one(INFINITE, ec))
    if (n != (std::numeric_limits<size_t>::max)())
      ++n;
  return n;
}

size_t win_iocp_io_context::run_one(boost::system::error_code& ec)
{
  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
  {
    stop();
    ec = boost::system::error_code();
    return 0;
  }

  win_iocp_thread_info this_thread;
  thread_call_stack::context ctx(this, this_thread);

  return do_one(INFINITE, ec);
}

size_t win_iocp_io_context::wait_one(long usec, boost::system::error_code& ec)
{
  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
  {
    stop();
    ec = boost::system::error_code();
    return 0;
  }

  win_iocp_thread_info this_thread;
  thread_call_stack::context ctx(this, this_thread);

  return do_one(usec < 0 ? INFINITE : ((usec - 1) / 1000 + 1), ec);
}

size_t win_iocp_io_context::poll(boost::system::error_code& ec)
{
  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
  {
    stop();
    ec = boost::system::error_code();
    return 0;
  }

  win_iocp_thread_info this_thread;
  thread_call_stack::context ctx(this, this_thread);

  size_t n = 0;
  while (do_one(0, ec))
    if (n != (std::numeric_limits<size_t>::max)())
      ++n;
  return n;
}

size_t win_iocp_io_context::poll_one(boost::system::error_code& ec)
{
  if (::InterlockedExchangeAdd(&outstanding_work_, 0) == 0)
  {
    stop();
    ec = boost::system::error_code();
    return 0;
  }

  win_iocp_thread_info this_thread;
  thread_call_stack::context ctx(this, this_thread);

  return do_one(0, ec);
}

void win_iocp_io_context::stop()
{
  if (::InterlockedExchange(&stopped_, 1) == 0)
  {
    if (::InterlockedExchange(&stop_event_posted_, 1) == 0)
    {
      if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, 0))
      {
        DWORD last_error = ::GetLastError();
        boost::system::error_code ec(last_error,
            boost::asio::error::get_system_category());
        boost::asio::detail::throw_error(ec, "pqcs");
      }
    }
  }
}

void win_iocp_io_context::post_deferred_completion(win_iocp_operation* op)
{
  // Flag the operation as ready.
  op->ready_ = 1;

  // Enqueue the operation on the I/O completion port.
  if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, op))
  {
    // Out of resources. Put on completed queue instead.
    mutex::scoped_lock lock(dispatch_mutex_);
    completed_ops_.push(op);
    ::InterlockedExchange(&dispatch_required_, 1);
  }
}

void win_iocp_io_context::post_deferred_completions(
    op_queue<win_iocp_operation>& ops)
{
  while (win_iocp_operation* op = ops.front())
  {
    ops.pop();

    // Flag the operation as ready.
    op->ready_ = 1;

    // Enqueue the operation on the I/O completion port.
    if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, op))
    {
      // Out of resources. Put on completed queue instead.
      mutex::scoped_lock lock(dispatch_mutex_);
      completed_ops_.push(op);
      completed_ops_.push(ops);
      ::InterlockedExchange(&dispatch_required_, 1);
    }
  }
}

void win_iocp_io_context::abandon_operations(
    op_queue<win_iocp_operation>& ops)
{
  while (win_iocp_operation* op = ops.front())
  {
    ops.pop();
    ::InterlockedDecrement(&outstanding_work_);
    op->destroy();
  }
}

void win_iocp_io_context::on_pending(win_iocp_operation* op)
{
  if (::InterlockedCompareExchange(&op->ready_, 1, 0) == 1)
  {
    // Enqueue the operation on the I/O completion port.
    if (!::PostQueuedCompletionStatus(iocp_.handle,
          0, overlapped_contains_result, op))
    {
      // Out of resources. Put on completed queue instead.
      mutex::scoped_lock lock(dispatch_mutex_);
      completed_ops_.push(op);
      ::InterlockedExchange(&dispatch_required_, 1);
    }
  }
}

void win_iocp_io_context::on_completion(win_iocp_operation* op,
    DWORD last_error, DWORD bytes_transferred)
{
  // Flag that the operation is ready for invocation.
  op->ready_ = 1;

  // Store results in the OVERLAPPED structure.
  op->Internal = reinterpret_cast<ulong_ptr_t>(
      &boost::asio::error::get_system_category());
  op->Offset = last_error;
  op->OffsetHigh = bytes_transferred;

  // Enqueue the operation on the I/O completion port.
  if (!::PostQueuedCompletionStatus(iocp_.handle,
        0, overlapped_contains_result, op))
  {
    // Out of resources. Put on completed queue instead.
    mutex::scoped_lock lock(dispatch_mutex_);
    completed_ops_.push(op);
    ::InterlockedExchange(&dispatch_required_, 1);
  }
}

void win_iocp_io_context::on_completion(win_iocp_operation* op,
    const boost::system::error_code& ec, DWORD bytes_transferred)
{
  // Flag that the operation is ready for invocation.
  op->ready_ = 1;

  // Store results in the OVERLAPPED structure.
  op->Internal = reinterpret_cast<ulong_ptr_t>(&ec.category());
  op->Offset = ec.value();
  op->OffsetHigh = bytes_transferred;

  // Enqueue the operation on the I/O completion port.
  if (!::PostQueuedCompletionStatus(iocp_.handle,
        0, overlapped_contains_result, op))
  {
    // Out of resources. Put on completed queue instead.
    mutex::scoped_lock lock(dispatch_mutex_);
    completed_ops_.push(op);
    ::InterlockedExchange(&dispatch_required_, 1);
  }
}

size_t win_iocp_io_context::do_one(DWORD msec, boost::system::error_code& ec)
{
  for (;;)
  {
    // Try to acquire responsibility for dispatching timers and completed ops.
    if (::InterlockedCompareExchange(&dispatch_required_, 0, 1) == 1)
    {
      mutex::scoped_lock lock(dispatch_mutex_);

      // Dispatch pending timers and operations.
      op_queue<win_iocp_operation> ops;
      ops.push(completed_ops_);
      timer_queues_.get_ready_timers(ops);
      post_deferred_completions(ops);
      update_timeout();
    }

    // Get the next operation from the queue.
    DWORD bytes_transferred = 0;
    dword_ptr_t completion_key = 0;
    LPOVERLAPPED overlapped = 0;
    ::SetLastError(0);
    BOOL ok = ::GetQueuedCompletionStatus(iocp_.handle,
        &bytes_transferred, &completion_key, &overlapped,
        msec < gqcs_timeout_ ? msec : gqcs_timeout_);
    DWORD last_error = ::GetLastError();

    if (overlapped)
    {
      win_iocp_operation* op = static_cast<win_iocp_operation*>(overlapped);
      boost::system::error_code result_ec(last_error,
          boost::asio::error::get_system_category());

      // We may have been passed the last_error and bytes_transferred in the
      // OVERLAPPED structure itself.
      if (completion_key == overlapped_contains_result)
      {
        result_ec = boost::system::error_code(static_cast<int>(op->Offset),
            *reinterpret_cast<boost::system::error_category*>(op->Internal));
        bytes_transferred = op->OffsetHigh;
      }

      // Otherwise ensure any result has been saved into the OVERLAPPED
      // structure.
      else
      {
        op->Internal = reinterpret_cast<ulong_ptr_t>(&result_ec.category());
        op->Offset = result_ec.value();
        op->OffsetHigh = bytes_transferred;
      }

      // Dispatch the operation only if ready. The operation may not be ready
      // if the initiating function (e.g. a call to WSARecv) has not yet
      // returned. This is because the initiating function still wants access
      // to the operation's OVERLAPPED structure.
      if (::InterlockedCompareExchange(&op->ready_, 1, 0) == 1)
      {
        // Ensure the count of outstanding work is decremented on block exit.
        work_finished_on_block_exit on_exit = { this };
        (void)on_exit;

        op->complete(this, result_ec, bytes_transferred);
        ec = boost::system::error_code();
        return 1;
      }
    }
    else if (!ok)
    {
      if (last_error != WAIT_TIMEOUT)
      {
        ec = boost::system::error_code(last_error,
            boost::asio::error::get_system_category());
        return 0;
      }

      // If we're waiting indefinitely we need to keep going until we get a
      // real handler.
      if (msec == INFINITE)
        continue;

      ec = boost::system::error_code();
      return 0;
    }
    else if (completion_key == wake_for_dispatch)
    {
      // We have been woken up to try to acquire responsibility for dispatching
      // timers and completed operations.
    }
    else
    {
      // Indicate that there is no longer an in-flight stop event.
      ::InterlockedExchange(&stop_event_posted_, 0);

      // The stopped_ flag is always checked to ensure that any leftover
      // stop events from a previous run invocation are ignored.
      if (::InterlockedExchangeAdd(&stopped_, 0) != 0)
      {
        // Wake up next thread that is blocked on GetQueuedCompletionStatus.
        if (::InterlockedExchange(&stop_event_posted_, 1) == 0)
        {
          if (!::PostQueuedCompletionStatus(iocp_.handle, 0, 0, 0))
          {
            last_error = ::GetLastError();
            ec = boost::system::error_code(last_error,
                boost::asio::error::get_system_category());
            return 0;
          }
        }

        ec = boost::system::error_code();
        return 0;
      }
    }
  }
}

DWORD win_iocp_io_context::get_gqcs_timeout()
{
  OSVERSIONINFOEX osvi;
  ZeroMemory(&osvi, sizeof(osvi));
  osvi.dwOSVersionInfoSize = sizeof(osvi);
  osvi.dwMajorVersion = 6ul;

  const uint64_t condition_mask = ::VerSetConditionMask(
      0, VER_MAJORVERSION, VER_GREATER_EQUAL);

  if (!!::VerifyVersionInfo(&osvi, VER_MAJORVERSION, condition_mask))
    return INFINITE;

  return default_gqcs_timeout;
}

void win_iocp_io_context::do_add_timer_queue(timer_queue_base& queue)
{
  mutex::scoped_lock lock(dispatch_mutex_);

  timer_queues_.insert(&queue);

  if (!waitable_timer_.handle)
  {
    waitable_timer_.handle = ::CreateWaitableTimer(0, FALSE, 0);
    if (waitable_timer_.handle == 0)
    {
      DWORD last_error = ::GetLastError();
      boost::system::error_code ec(last_error,
          boost::asio::error::get_system_category());
      boost::asio::detail::throw_error(ec, "timer");
    }

    LARGE_INTEGER timeout;
    timeout.QuadPart = -max_timeout_usec;
    timeout.QuadPart *= 10;
    ::SetWaitableTimer(waitable_timer_.handle,
        &timeout, max_timeout_msec, 0, 0, FALSE);
  }

  if (!timer_thread_.get())
  {
    timer_thread_function thread_function = { this };
    timer_thread_.reset(new thread(thread_function, 65536));
  }
}

void win_iocp_io_context::do_remove_timer_queue(timer_queue_base& queue)
{
  mutex::scoped_lock lock(dispatch_mutex_);

  timer_queues_.erase(&queue);
}

void win_iocp_io_context::update_timeout()
{
  if (timer_thread_.get())
  {
    // There's no point updating the waitable timer if the new timeout period
    // exceeds the maximum timeout. In that case, we might as well wait for the
    // existing period of the timer to expire.
    long timeout_usec = timer_queues_.wait_duration_usec(max_timeout_usec);
    if (timeout_usec < max_timeout_usec)
    {
      LARGE_INTEGER timeout;
      timeout.QuadPart = -timeout_usec;
      timeout.QuadPart *= 10;
      ::SetWaitableTimer(waitable_timer_.handle,
          &timeout, max_timeout_msec, 0, 0, FALSE);
    }
  }
}

} // namespace detail
} // namespace asio
} // namespace boost

#include <boost/asio/detail/pop_options.hpp>

#endif // defined(BOOST_ASIO_HAS_IOCP)

#endif // BOOST_ASIO_DETAIL_IMPL_WIN_IOCP_IO_CONTEXT_IPP