C++ QReadWriteLock类代码示例

void tst_QReadWriteLock::readLockLoop()
{
    QReadWriteLock rwlock;
    int runs=10000;
    int i;
    for (i=0; i<runs; ++i) {
        rwlock.lockForRead();
    }
    for (i=0; i<runs; ++i) {
        rwlock.unlock();
    }
}

void tst_QReadWriteLock::writeLockLoop()
{
    /*
        If you include this, the test should print one line
        and then block.
    */
#if 0
    QReadWriteLock rwlock;
    int runs=10000;
    int i;
    for (i=0; i<runs; ++i) {
        rwlock.lockForWrite();
        qDebug("I am going to block now.");
    }
#endif
}

static PyObject *meth_QReadWriteLock_tryLockForRead(PyObject *sipSelf, PyObject *sipArgs)
{
    PyObject *sipParseErr = NULL;

    {
        QReadWriteLock *sipCpp;

        if (sipParseArgs(&sipParseErr, sipArgs, "B", &sipSelf, sipType_QReadWriteLock, &sipCpp))
        {
            bool sipRes;

            Py_BEGIN_ALLOW_THREADS
            sipRes = sipCpp->tryLockForRead();
            Py_END_ALLOW_THREADS

            return PyBool_FromLong(sipRes);
        }
    }

int main(int argc, char** argv)
{
  int i;
  const int n_threads = 10;
  std::vector<QThread*> tid(n_threads);

  s_iterations = argc > 1 ? atoi(argv[1]) : 1000;

  fprintf(stderr, "Start of test.\n");

  {
    // Stack-allocated reader-writer lock.
    QReadWriteLock RWL;
    RWL.lockForRead();
    RWL.unlock();
    RWL.lockForWrite();
    RWL.unlock();
  }

  pthread_barrier_init(&s_barrier, 0, n_threads);
  s_pRWlock = new QReadWriteLock();
  for (i = 0; i < n_threads; i++)
  {
    tid[i] = new IncThread;
    tid[i]->start();
  }
  for (i = 0; i < n_threads; i++)
  {
    tid[i]->wait();
    delete tid[i];
  }
  delete s_pRWlock;
  s_pRWlock = 0;
  pthread_barrier_destroy(&s_barrier);

  if (s_counter == n_threads * s_iterations)
    fprintf(stderr, "Test successful.\n");
  else
    fprintf(stderr, "Test failed: counter = %d, should be %d\n",
            s_counter, n_threads * s_iterations);

  return 0;
}

void tst_QGlobalStatic::threadStressTest()
{
    class ThreadStressTestThread: public QThread
    {
    public:
        QReadWriteLock *lock;
        void run()
        {
            QReadLocker l(lock);
            //usleep(qrand() * 200 / RAND_MAX);
            // thundering herd
            try {
                threadStressTestGS();
            } catch (int) {
            }
        }
    };

    ThrowingType::constructedCount.store(0);
    ThrowingType::destructedCount.store(0);
    int expectedConstructionCount = threadStressTestControlVar.load() + 1;
    if (expectedConstructionCount <= 0)
        QSKIP("This test cannot be run more than once");

    const int numThreads = 200;
    ThreadStressTestThread threads[numThreads];
    QReadWriteLock lock;
    lock.lockForWrite();
    for (int i = 0; i < numThreads; ++i) {
        threads[i].lock = &lock;
        threads[i].start();
    }

    // wait for all threads
    // release the herd
    lock.unlock();

    for (int i = 0; i < numThreads; ++i)
        threads[i].wait();

    QCOMPARE(ThrowingType::constructedCount.loadAcquire(), expectedConstructionCount);
    QCOMPARE(ThrowingType::destructedCount.loadAcquire(), 0);
}

int mythdir_opendir(const char *dirname)
{
    LOG(VB_FILE, LOG_DEBUG, LOC + QString("mythdir_opendir(%1)").arg(dirname));

    int id = 0;
    if (strncmp(dirname, "myth://", 7))
    {
        DIR *dir = opendir(dirname);

        m_dirWrapperLock.lockForWrite();
        id = getNextDirID();
        m_localdirs[id] = dir;
        m_dirnames[id] = dirname;
        m_dirWrapperLock.unlock();
    }
    else
    {
        QStringList list;
        QUrl qurl(dirname);
        QString storageGroup = qurl.userName();

        list.clear();

        if (storageGroup.isEmpty())
            storageGroup = "Default";

        list << "QUERY_SG_GETFILELIST";
        list << qurl.host();
        list << storageGroup;

        QString path = qurl.path();
        if (!qurl.fragment().isEmpty())
            path += "#" + qurl.fragment();

        list << path;
        list << "1";

        bool ok = gCoreContext->SendReceiveStringList(list);

        if ((!ok) ||
            ((list.size() == 1) && (list[0] == "EMPTY LIST")))
            list.clear();

        m_dirWrapperLock.lockForWrite();
        id = getNextDirID();
        m_remotedirs[id] = list;
        m_remotedirPositions[id] = 0;
        m_dirnames[id] = dirname;
        m_dirWrapperLock.unlock();
    }

    return id;
}

void TonemapperThread::terminateRequested() {
	if (forciblyTerminated)
		return;
	lock.lockForWrite();
	pregamma=-1;
	xsize=-1;
	lock.unlock();
	forciblyTerminated=true;
	//HACK oddly enough for the other operators we cannot emit finished (it segfaults)
	if (opts.tmoperator==mantiuk || opts.tmoperator==ashikhmin || opts.tmoperator==pattanaik )
		emit finished();
	terminate();
}

int mythdir_check(int id)
{
    LOG(VB_FILE, LOG_DEBUG, QString("mythdir_check(%1)").arg(id));
    int result = 0;

    m_dirWrapperLock.lockForWrite();
    if (m_localdirs.contains(id))
        result = 1;
    else if (m_remotedirs.contains(id))
        result = 1;
    m_dirWrapperLock.unlock();

    return result;
}

//! Entrypoint for LogThread
//! Check to see if there are things to log and if so, write them to disk.
//! Otherwise, wait 100ms and check again.
//! Exit only when "go" is false AND all queued events are written
void LogThread::run()
{
	while(! actionLog.isEmpty() || go) {
		while(! actionLog.isEmpty()) { // Write all queued log entries
			lock.lockForRead();
			LogEntry entry = actionLog.dequeue();
			lock.unlock();
			outStream << entry.dat.asInt << entry.position;
			++logEntryCountByServo[entry.dat.asBitfield.servoIndex];
			yieldCurrentThread();
		}
		msleep(100);
	}
	exit(0);
}

QByteArray readData()
{
    lock.lockForRead();
    ...
    lock.unlock();
    return data;
}

char *mythdir_readdir(int dirID)
{
    char *result = NULL;

    LOG(VB_FILE, LOG_DEBUG, LOC + QString("mythdir_readdir(%1)").arg(dirID));

    m_dirWrapperLock.lockForRead();
    if (m_remotedirs.contains(dirID))
    {
        int pos = m_remotedirPositions[dirID];
        if (m_remotedirs[dirID].size() >= (pos+1))
        {
            result = strdup(m_remotedirs[dirID][pos].toLocal8Bit().constData());
            pos++;
            m_remotedirPositions[dirID] = pos;
        }
    }
    else if (m_localdirs.contains(dirID))
    {
        int sz = offsetof(struct dirent, d_name) + FILENAME_MAX + 1;
        struct dirent *entry =
            reinterpret_cast<struct dirent*>(calloc(1, sz));
        struct dirent *r = NULL;
        if ((0 == readdir_r(m_localdirs[dirID], entry, &r)) && (NULL != r))
            result = strdup(r->d_name);
        free(entry);
    }

int mythfile_stat_fd(int fileID, struct stat *buf)
{
    LOG(VB_FILE, LOG_DEBUG, QString("mythfile_stat_fd(%1, %2)")
            .arg(fileID).arg((long long)buf));

    m_fileWrapperLock.lockForRead();
    if (!m_filenames.contains(fileID))
    {
        m_fileWrapperLock.unlock();
        return -1;
    }
    QString filename = m_filenames[fileID];
    m_fileWrapperLock.unlock();

    return mythfile_stat(filename.toLocal8Bit().constData(), buf);
}

off_t mythfile_tell(int fileID)
{
    off_t result = -1;

    LOG(VB_FILE, LOG_DEBUG, LOC + QString("mythfile_tell(%1)").arg(fileID));

    m_fileWrapperLock.lockForRead();
    if (m_ringbuffers.contains(fileID))
        result = m_ringbuffers[fileID]->Seek(0, SEEK_CUR);
    else if (m_remotefiles.contains(fileID))
        result = m_remotefiles[fileID]->Seek(0, SEEK_CUR);
    else if (m_localfiles.contains(fileID))
        result = lseek(m_localfiles[fileID], 0, SEEK_CUR);
    m_fileWrapperLock.unlock();

    return result;
}

void ReaderThread::run()
{
    ...
    lock.lockForRead();
    read_file();
    lock.unlock();
    ...
}

int mythfile_check(int id)
{
    VERBOSE(VB_FILE+VB_EXTRA,
            QString("mythfile_check(%1)").arg(id));
    int result = 0;

    m_fileWrapperLock.lockForWrite();
    if (m_localfiles.contains(id))
        result = 1;
    else if (m_remotefiles.contains(id))
        result = 1;
    else if (m_ringbuffers.contains(id))
        result = 1;
    m_fileWrapperLock.unlock();

    return result;
}