clib/hbmutex.cpp

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/*
 * With permission to reuse:
 * Author:  Thomas Volkert
 * Libary:  Homerbase http://www.homer-conferencing.com/
 * Since:   2010-09-20
 */

#include "hbmutex.h"
#include "logfile.h"


Mutex::Mutex()
{
        bool tResult = false;
#ifdef _WIN32
        mPThreadMutex = CreateMutex(NULL, false, NULL);
        tResult = (mPThreadMutex != NULL);
#else
        mPThreadMutex = (pthread_mutex_t*)malloc(sizeof(pthread_mutex_t));
        tResult = (pthread_mutex_init(mPThreadMutex, NULL) == 0);
#endif
        if (!tResult)
        Log("Initiation of mutex failed");
}

Mutex::~Mutex()
{
    bool tResult = false;
#ifdef _WIN32
        tResult = (CloseHandle(mPThreadMutex) != 0);
#else
        tResult = (pthread_mutex_destroy(mPThreadMutex) == 0);
        free(mPThreadMutex);
#endif
    if (!tResult)
                Log("Destruction of mutex failed");
}


bool Mutex::lock()
{
#ifdef _WIN32
        return (WaitForSingleObject(mPThreadMutex, INFINITE) != WAIT_FAILED);
#else
        return !pthread_mutex_lock(mPThreadMutex);
#endif
}

bool Mutex::unlock()
{
#ifdef _WIN32
        return (ReleaseMutex(mPThreadMutex) != 0);
#else
        return !pthread_mutex_unlock(mPThreadMutex);
#endif
}

bool Mutex::tryLock()
{
        bool tResult = false;
#ifdef _WIN32
        switch(WaitForSingleObject(mPThreadMutex, (DWORD)0))
        {
        case WAIT_ABANDONED:
        case WAIT_TIMEOUT:
        case WAIT_FAILED:
                break;
        case WAIT_OBJECT_0:
                tResult = true;
                break;
        }
#else
        switch(pthread_mutex_trylock(mPThreadMutex))
        {
                case EDEADLK:
                        Log("Lock already held by calling thread");
                        break;
                case EBUSY: // lock can't be obtained because it is busy
                        break;
                case EINVAL:
                        Log("Lock was found in uninitialized state");
                        break;
                case EFAULT:
                        Log("Invalid lock pointer was given");
                        break;
                case 0: // lock was free and is obtained now
                        tResult = true;
                        break;
                default:
                        Log("Error occurred while trying to get lock: code %d", tResult);
                        break;
        }
#endif
        return tResult;
}


bool Mutex::tryLock(int pMSecs)
{
        bool tResult = false;
#ifdef _WIN32
        switch(WaitForSingleObject(mPThreadMutex, (DWORD)pMSecs))
        {
        case WAIT_ABANDONED:
        case WAIT_TIMEOUT:
        case WAIT_FAILED:
                break;
        case WAIT_OBJECT_0:
                tResult = true;
                break;
        }
#else
        struct timespec tTimeout;

        if (clock_gettime(CLOCK_REALTIME, &tTimeout) == -1)
                Log("Failed to get time from clock");

        // add msecs to current time stamp
        tTimeout.tv_nsec += pMSecs * 1000 * 1000;

        switch(pthread_mutex_timedlock(mPThreadMutex, &tTimeout))
        {
                case EDEADLK:
                        Log("Lock already held by calling thread");
                        break;
                case EBUSY: // lock can't be obtained because it is busy
                        break;
                case EINVAL:
                        Log("Lock was found in uninitialized state");
                        break;
                case EFAULT:
                        Log("Invalid lock pointer was given");
                        break;
                case ETIMEDOUT:
                        Log("Lock couldn't be obtained in given time");
                        break;
                case 0: // lock was free and is obtained now
                        tResult = true;
                        break;
                default:
                        Log("Error occurred while trying to get lock: code %d", tResult);
                        break;
        }
#endif
        return tResult;
}