summaryrefslogtreecommitdiffstats
path: root/ext/asio/detail/reactor_op_queue.hpp
blob: 233c0aec167f07e7b90a5087ea4ba7af92235fe7 (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
//
// reactor_op_queue.hpp
// ~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2010 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 ASIO_DETAIL_REACTOR_OP_QUEUE_HPP
#define ASIO_DETAIL_REACTOR_OP_QUEUE_HPP

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

#include "asio/detail/push_options.hpp"

#include "asio/error.hpp"
#include "asio/detail/hash_map.hpp"
#include "asio/detail/noncopyable.hpp"
#include "asio/detail/op_queue.hpp"
#include "asio/detail/reactor_op.hpp"

namespace asio {
namespace detail {

template <typename Descriptor>
class reactor_op_queue
  : private noncopyable
{
public:
  // Constructor.
  reactor_op_queue()
    : operations_()
  {
  }

  // Add a new operation to the queue. Returns true if this is the only
  // operation for the given descriptor, in which case the reactor's event
  // demultiplexing function call may need to be interrupted and restarted.
  bool enqueue_operation(Descriptor descriptor, reactor_op* op)
  {
    typedef typename operations_map::iterator iterator;
    typedef typename operations_map::value_type value_type;
    std::pair<iterator, bool> entry =
      operations_.insert(value_type(descriptor, operations()));
    entry.first->second.op_queue_.push(op);
    return entry.second;
  }

  // Cancel all operations associated with the descriptor. Any operations
  // pending for the descriptor will be notified that they have been cancelled
  // next time perform_cancellations is called. Returns true if any operations
  // were cancelled, in which case the reactor's event demultiplexing function
  // may need to be interrupted and restarted.
  bool cancel_operations(Descriptor descriptor, op_queue<operation>& ops,
      const asio::error_code& ec =
        asio::error::operation_aborted)
  {
    typename operations_map::iterator i = operations_.find(descriptor);
    if (i != operations_.end())
    {
      while (reactor_op* op = i->second.op_queue_.front())
      {
        op->ec_ = ec;
        i->second.op_queue_.pop();
        ops.push(op);
      }
      operations_.erase(i);
      return true;
    }

    return false;
  }

  // Whether there are no operations in the queue.
  bool empty() const
  {
    return operations_.empty();
  }

  // Determine whether there are any operations associated with the descriptor.
  bool has_operation(Descriptor descriptor) const
  {
    return operations_.find(descriptor) != operations_.end();
  }

  // Perform the operations corresponding to the descriptor. Returns true if
  // there are still unfinished operations queued for the descriptor.
  bool perform_operations(Descriptor descriptor, op_queue<operation>& ops)
  {
    typename operations_map::iterator i = operations_.find(descriptor);
    if (i != operations_.end())
    {
      while (reactor_op* op = i->second.op_queue_.front())
      {
        if (op->perform())
        {
          i->second.op_queue_.pop();
          ops.push(op);
        }
        else
        {
          return true;
        }
      }
      operations_.erase(i);
    }
    return false;
  }

  // Fill a descriptor set with the descriptors corresponding to each active
  // operation. The op_queue is used only when descriptors fail to be added to
  // the descriptor set.
  template <typename Descriptor_Set>
  void get_descriptors(Descriptor_Set& descriptors, op_queue<operation>& ops)
  {
    typename operations_map::iterator i = operations_.begin();
    while (i != operations_.end())
    {
      Descriptor descriptor = i->first;
      ++i;
      if (!descriptors.set(descriptor))
      {
        asio::error_code ec(error::fd_set_failure);
        cancel_operations(descriptor, ops, ec);
      }
    }
  }

  // Perform the operations corresponding to the ready file descriptors
  // contained in the given descriptor set.
  template <typename Descriptor_Set>
  void perform_operations_for_descriptors(
      const Descriptor_Set& descriptors, op_queue<operation>& ops)
  {
    typename operations_map::iterator i = operations_.begin();
    while (i != operations_.end())
    {
      typename operations_map::iterator op_iter = i++;
      if (descriptors.is_set(op_iter->first))
      {
        while (reactor_op* op = op_iter->second.op_queue_.front())
        {
          if (op->perform())
          {
            op_iter->second.op_queue_.pop();
            ops.push(op);
          }
          else
          {
            break;
          }
        }

        if (op_iter->second.op_queue_.empty())
          operations_.erase(op_iter);
      }
    }
  }

  // Get all operations owned by the queue.
  void get_all_operations(op_queue<operation>& ops)
  {
    typename operations_map::iterator i = operations_.begin();
    while (i != operations_.end())
    {
      typename operations_map::iterator op_iter = i++;
      ops.push(op_iter->second.op_queue_);
      operations_.erase(op_iter);
    }
  }

private:
  struct operations
  {
    operations() {}
    operations(const operations&) {}
    void operator=(const operations&) {}

    // The operations waiting on the desccriptor.
    op_queue<reactor_op> op_queue_;
  };

  // The type for a map of operations.
  typedef hash_map<Descriptor, operations> operations_map;

  // The operations that are currently executing asynchronously.
  operations_map operations_;
};

} // namespace detail
} // namespace asio

#include "asio/detail/pop_options.hpp"

#endif // ASIO_DETAIL_REACTOR_OP_QUEUE_HPP