1 /*
2 * Copyright 2019 The Android Open Source Project
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
17 #include "os/handler.h"
18
19 #include <sys/eventfd.h>
20 #include <unistd.h>
21 #include <cstring>
22
23 #include "common/bind.h"
24 #include "common/callback.h"
25 #include "os/log.h"
26 #include "os/reactor.h"
27 #include "os/utils.h"
28
29 #ifndef EFD_SEMAPHORE
30 #define EFD_SEMAPHORE 1
31 #endif
32
33 namespace bluetooth {
34 namespace os {
35
Handler(Thread * thread)36 Handler::Handler(Thread* thread)
37 : tasks_(new std::queue<OnceClosure>()), thread_(thread), fd_(eventfd(0, EFD_SEMAPHORE | EFD_NONBLOCK)) {
38 ASSERT(fd_ != -1);
39 reactable_ = thread_->GetReactor()->Register(fd_, common::Bind(&Handler::handle_next_event, common::Unretained(this)),
40 common::Closure());
41 }
42
~Handler()43 Handler::~Handler() {
44 {
45 std::lock_guard<std::mutex> lock(mutex_);
46 ASSERT_LOG(was_cleared(), "Handlers must be cleared before they are destroyed");
47 }
48
49 int close_status;
50 RUN_NO_INTR(close_status = close(fd_));
51 ASSERT(close_status != -1);
52 }
53
Post(OnceClosure closure)54 void Handler::Post(OnceClosure closure) {
55 {
56 std::lock_guard<std::mutex> lock(mutex_);
57 if (was_cleared()) {
58 return;
59 }
60 tasks_->emplace(std::move(closure));
61 }
62 uint64_t val = 1;
63 auto write_result = eventfd_write(fd_, val);
64 ASSERT(write_result != -1);
65 }
66
Clear()67 void Handler::Clear() {
68 std::queue<OnceClosure>* tmp = nullptr;
69 {
70 std::lock_guard<std::mutex> lock(mutex_);
71 ASSERT_LOG(!was_cleared(), "Handlers must only be cleared once");
72 std::swap(tasks_, tmp);
73 }
74 delete tmp;
75
76 uint64_t val;
77 while (eventfd_read(fd_, &val) == 0) {
78 }
79
80 thread_->GetReactor()->Unregister(reactable_);
81 reactable_ = nullptr;
82 }
83
WaitUntilStopped(std::chrono::milliseconds timeout)84 void Handler::WaitUntilStopped(std::chrono::milliseconds timeout) {
85 ASSERT(reactable_ == nullptr);
86 ASSERT(thread_->GetReactor()->WaitForUnregisteredReactable(timeout));
87 }
88
handle_next_event()89 void Handler::handle_next_event() {
90 common::OnceClosure closure;
91 {
92 std::lock_guard<std::mutex> lock(mutex_);
93 uint64_t val = 0;
94 auto read_result = eventfd_read(fd_, &val);
95
96 if (was_cleared()) {
97 return;
98 }
99 ASSERT_LOG(read_result != -1, "eventfd read error %d %s", errno, strerror(errno));
100
101 closure = std::move(tasks_->front());
102 tasks_->pop();
103 }
104 std::move(closure).Run();
105 }
106
107 } // namespace os
108 } // namespace bluetooth
109