Files
android_bootable_recovery/tw_atomic.cpp
bigbiff 7abc5fe195 Add cancel backup capability.
This will stop the iteration of the partition objects, kill the
current twrpTar thread and remove the backup directory.

Implement TWAtomicInt class to give us a wrapper that automatically
uses mutexes before the read and write to help ensure that the
reads and writes will be atomic based on documentation.

Change-Id: I645b22bc980a292e9c7202acb24ffd22ebe68c63
2015-01-27 15:07:19 +01:00

69 lines
1.8 KiB
C++

/*
* Copyright (C) 2015 The Team Win Recovery 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.
*/
#include <pthread.h>
#include <stdio.h>
#include "tw_atomic.hpp"
/*
* According to this documentation:
* https://developer.android.com/training/articles/smp.html
* it is recommended to use mutexes instead of atomics. This class
* provides us with a wrapper to make "atomic" variables easy to use.
*/
TWAtomicInt::TWAtomicInt(int initial_value /* = 0 */) {
if (pthread_mutex_init(&mutex_lock, NULL) != 0) {
// This should hopefully never happen. If it does, the
// operations will not be atomic, but we will allow things to
// continue anyway after logging the issue and just hope for
// the best.
printf("TWAtomic error initializing mutex.\n");
use_mutex = false;
} else {
use_mutex = true;
}
value = initial_value;
}
TWAtomicInt::~TWAtomicInt() {
if (use_mutex)
pthread_mutex_destroy(&mutex_lock);
}
void TWAtomicInt::set_value(int new_value) {
if (use_mutex) {
pthread_mutex_lock(&mutex_lock);
value = new_value;
pthread_mutex_unlock(&mutex_lock);
} else {
value = new_value;
}
}
int TWAtomicInt::get_value(void) {
int ret_val;
if (use_mutex) {
pthread_mutex_lock(&mutex_lock);
ret_val = value;
pthread_mutex_unlock(&mutex_lock);
} else {
ret_val = value;
}
return ret_val;
}