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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ASYNCHRONOUS_CLOSE_MONITOR_H_included
#define ASYNCHRONOUS_CLOSE_MONITOR_H_included
#include <pthread.h>
// Public API for library function.
extern "C" {
void async_close_monitor_destroy(void* instance);
void async_close_monitor_static_init();
void async_close_monitor_signal_blocked_threads(int fd);
int async_close_monitor_was_signalled(const void* instance);
void* async_close_monitor_create(int fd);
}
/**
* AsynchronousCloseMonitor helps implement Java's asynchronous close semantics.
*
* AsynchronousCloseMonitor::init must be called before anything else.
*
* Every blocking I/O operation must be surrounded by an AsynchronousCloseMonitor
* instance. For example:
*
* {
* AsynchronousCloseMonitor monitor(fd);
* byteCount = ::read(fd, buf, sizeof(buf));
* }
*
* To interrupt all threads currently blocked on file descriptor 'fd', call signalBlockedThreads:
*
* AsynchronousCloseMonitor::signalBlockedThreads(fd);
*
* To test to see if the interruption was due to the signalBlockedThreads call:
*
* monitor.wasSignaled();
*/
class AsynchronousCloseMonitor {
public:
explicit AsynchronousCloseMonitor(int fd) {
instance_ = async_close_monitor_create(fd);
}
~AsynchronousCloseMonitor() {
async_close_monitor_destroy(instance_);
}
bool wasSignaled() const {
return async_close_monitor_was_signalled(instance_) != 0;
}
static void init() {
async_close_monitor_static_init();
}
static void signalBlockedThreads(int fd) {
async_close_monitor_signal_blocked_threads(fd);
}
private:
AsynchronousCloseMonitor(const AsynchronousCloseMonitor&) = delete;
AsynchronousCloseMonitor& operator=(const AsynchronousCloseMonitor&) = delete;
void* instance_;
};
#endif // ASYNCHRONOUS_CLOSE_MONITOR_H_included
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