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
|
//
// detail/strand_executor_service.hpp
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2018 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_STRAND_EXECUTOR_SERVICE_HPP
#define BOOST_ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP
#if defined(_MSC_VER) && (_MSC_VER >= 1200)
# pragma once
#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
#include <boost/asio/detail/config.hpp>
#include <boost/asio/detail/atomic_count.hpp>
#include <boost/asio/detail/executor_op.hpp>
#include <boost/asio/detail/memory.hpp>
#include <boost/asio/detail/mutex.hpp>
#include <boost/asio/detail/op_queue.hpp>
#include <boost/asio/detail/scheduler_operation.hpp>
#include <boost/asio/detail/scoped_ptr.hpp>
#include <boost/asio/execution_context.hpp>
#include <boost/asio/detail/push_options.hpp>
namespace boost {
namespace asio {
namespace detail {
// Default service implementation for a strand.
class strand_executor_service
: public execution_context_service_base<strand_executor_service>
{
public:
// The underlying implementation of a strand.
class strand_impl
{
public:
BOOST_ASIO_DECL ~strand_impl();
private:
friend class strand_executor_service;
// Mutex to protect access to internal data.
mutex* mutex_;
// Indicates whether the strand is currently "locked" by a handler. This
// means that there is a handler upcall in progress, or that the strand
// itself has been scheduled in order to invoke some pending handlers.
bool locked_;
// Indicates that the strand has been shut down and will accept no further
// handlers.
bool shutdown_;
// The handlers that are waiting on the strand but should not be run until
// after the next time the strand is scheduled. This queue must only be
// modified while the mutex is locked.
op_queue<scheduler_operation> waiting_queue_;
// The handlers that are ready to be run. Logically speaking, these are the
// handlers that hold the strand's lock. The ready queue is only modified
// from within the strand and so may be accessed without locking the mutex.
op_queue<scheduler_operation> ready_queue_;
// Pointers to adjacent handle implementations in linked list.
strand_impl* next_;
strand_impl* prev_;
// The strand service in where the implementation is held.
strand_executor_service* service_;
};
typedef shared_ptr<strand_impl> implementation_type;
// Construct a new strand service for the specified context.
BOOST_ASIO_DECL explicit strand_executor_service(execution_context& context);
// Destroy all user-defined handler objects owned by the service.
BOOST_ASIO_DECL void shutdown();
// Create a new strand_executor implementation.
BOOST_ASIO_DECL implementation_type create_implementation();
// Request invocation of the given function.
template <typename Executor, typename Function, typename Allocator>
static void dispatch(const implementation_type& impl, Executor& ex,
BOOST_ASIO_MOVE_ARG(Function) function, const Allocator& a);
// Request invocation of the given function and return immediately.
template <typename Executor, typename Function, typename Allocator>
static void post(const implementation_type& impl, Executor& ex,
BOOST_ASIO_MOVE_ARG(Function) function, const Allocator& a);
// Request invocation of the given function and return immediately.
template <typename Executor, typename Function, typename Allocator>
static void defer(const implementation_type& impl, Executor& ex,
BOOST_ASIO_MOVE_ARG(Function) function, const Allocator& a);
// Determine whether the strand is running in the current thread.
BOOST_ASIO_DECL static bool running_in_this_thread(
const implementation_type& impl);
private:
friend class strand_impl;
template <typename Executor> class invoker;
// Adds a function to the strand. Returns true if it acquires the lock.
BOOST_ASIO_DECL static bool enqueue(const implementation_type& impl,
scheduler_operation* op);
// Mutex to protect access to the service-wide state.
mutex mutex_;
// Number of mutexes shared between all strand objects.
enum { num_mutexes = 193 };
// Pool of mutexes.
scoped_ptr<mutex> mutexes_[num_mutexes];
// Extra value used when hashing to prevent recycled memory locations from
// getting the same mutex.
std::size_t salt_;
// The head of a linked list of all implementations.
strand_impl* impl_list_;
};
} // namespace detail
} // namespace asio
} // namespace boost
#include <boost/asio/detail/pop_options.hpp>
#include <boost/asio/detail/impl/strand_executor_service.hpp>
#if defined(BOOST_ASIO_HEADER_ONLY)
# include <boost/asio/detail/impl/strand_executor_service.ipp>
#endif // defined(BOOST_ASIO_HEADER_ONLY)
#endif // BOOST_ASIO_DETAIL_STRAND_EXECUTOR_SERVICE_HPP
|
