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Rolf Badorekef2bf512019-08-20 11:17:15 +03001/*
2 Copyright (c) 2018-2019 Nokia.
3
4 Licensed under the Apache License, Version 2.0 (the "License");
5 you may not use this file except in compliance with the License.
6 You may obtain a copy of the License at
7
8 http://www.apache.org/licenses/LICENSE-2.0
9
10 Unless required by applicable law or agreed to in writing, software
11 distributed under the License is distributed on an "AS IS" BASIS,
12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 See the License for the specific language governing permissions and
14 limitations under the License.
15*/
16
Timo Tietavainena0745d22019-11-28 09:55:22 +020017/*
18 * This source code is part of the near-RT RIC (RAN Intelligent Controller)
19 * platform project (RICP).
20*/
21
Rolf Badorekef2bf512019-08-20 11:17:15 +030022#include "private/eventfd.hpp"
23#include <sys/eventfd.h>
24#include "private/abort.hpp"
25#include "private/engine.hpp"
26#include "private/system.hpp"
27
28using namespace shareddatalayer;
29
30namespace
31{
32 /*
33 * Simple wrapper for executing the given callback without expecting
34 * exceptions. If callback throws, we'll crash.
35 */
36 void execute(const EventFD::Callback& callback) noexcept
37 {
38 callback();
39 }
40}
41
42EventFD::EventFD(Engine& engine):
43 EventFD(System::getSystem(), engine)
44{
45}
46
47EventFD::EventFD(System& system, Engine& engine):
48 system(system),
49 fd(system, system.eventfd(0U, EFD_CLOEXEC | EFD_NONBLOCK))
50{
51 engine.addMonitoredFD(fd, Engine::EVENT_IN, std::bind(&EventFD::handleEvents, this));
52}
53
54EventFD::~EventFD()
55{
56}
57
58void EventFD::post(const Callback& callback)
59{
60 if (!callback)
61 SHAREDDATALAYER_ABORT("A null callback was provided");
62
63 atomicPushBack(callback);
64 static const uint64_t value(1U);
65 system.write(fd, &value, sizeof(value));
66}
67
68void EventFD::atomicPushBack(const Callback& callback)
69{
70 std::lock_guard<std::mutex> guard(callbacksMutex);
71 callbacks.push_back(callback);
72}
73
74EventFD::Callbacks EventFD::atomicPopAll()
75{
76 std::lock_guard<std::mutex> guard(callbacksMutex);
77 Callbacks extractedCallbacks;
78 std::swap(callbacks, extractedCallbacks);
79 return extractedCallbacks;
80}
81
82void EventFD::handleEvents()
83{
84 uint64_t value;
85 system.read(fd, &value, sizeof(value));
86 executeCallbacks();
87}
88
89void EventFD::executeCallbacks()
90{
91 Callbacks callbacks(atomicPopAll());
92 while (!callbacks.empty())
93 popAndExecuteFirstCallback(callbacks);
94}
95
96void EventFD::popAndExecuteFirstCallback(Callbacks& callbacks)
97{
98 const auto callback(callbacks.front());
99 callbacks.pop_front();
100 execute(callback);
101}