Lockable.cc revision 2
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
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25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/*
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Copyright 2008 Sun Microsystems, Inc. All rights reserved.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * Use is subject to license terms.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include "Lockable.h"
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include <iostream>
ddc0e0b53c661f6e439e3b7072b3ef353eadb4afRichard Lowe#include <cstdio>
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include <cerrno>
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#include <unistd.h>
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisusing namespace std;
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define DEADLOCK_WARNING 10
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis#define LOCK_SLEEP 1
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Create a lockable instance and initialize internal locks
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr JasiukajtisLockable::Lockable() {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (pthread_mutex_init(&mutex, NULL)) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Free up a lockable instance
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr JasiukajtisLockable::~Lockable() {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis if (pthread_mutex_destroy(&mutex)) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis }
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Unlock the instance
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @precondition This thread must have locked the instance
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe * @postcondition The instance will be unlocked
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisvoid Lockable::unlock() {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis unlock(&mutex);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Unlock a given mutex lock
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @precondition The lock must be held by this thread
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @postcondition The lock will be released
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @param myMutex The lock to unlock
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisvoid Lockable::unlock(pthread_mutex_t *myMutex) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis pthread_mutex_unlock(myMutex);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Lock the instance
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @postcondition The lock will be held by this thread.
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisvoid Lockable::lock() {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis lock(&mutex);
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis}
1ec68d336ba97cd53f46053ac10401d16014d075Richard Lowe
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis/**
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @memo Lock the given mutex lock
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @postcondition The lock will be held by this thread
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis * @param myMutex The mutex lock to take
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis */
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtisvoid Lockable::lock(pthread_mutex_t *myMutex) {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis int status;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis int loop = 0;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis do {
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis loop++;
25c28e83beb90e7c80452a7c818c5e6f73a07dc8Piotr Jasiukajtis status = pthread_mutex_trylock(myMutex);
if (status) {
switch (pthread_mutex_trylock(myMutex)) {
case EFAULT:
cerr << "Lock failed: Fault" << endl;
break;
case EINVAL:
cerr << "Lock failed: Invalid" << endl;
break;
case EBUSY:
if (loop > DEADLOCK_WARNING) {
cerr << "Lock failed: Deadlock" << endl;
}
break;
case EOWNERDEAD:
cerr << "Lock failed: Owner died" << endl;
break;
case ELOCKUNMAPPED:
cerr << "Lock failed: Unmapped" << endl;
break;
case ENOTRECOVERABLE:
cerr << "Lock failed: not recoverable" << endl;
default:
if (loop > DEADLOCK_WARNING) {
cerr << "Lock failed: " <<strerror(status) << endl;
break;
}
}
} else {
break; // Lock taken succesfully
}
sleep(LOCK_SLEEP);
} while (status);
}