LockGuard.cpp

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#include "LockGuard.h"
#include "SerialPortHandler.h"

LockGuard::LockGuard() {
    // No active locks known on creation
    m_bLockedBySelf = false;
    m_bLockedByOthers = false;
    m_bLastLockedBySelf = false;
    m_bLastLockedByOthers = false;
}

LockGuard::~LockGuard() {
    if (m_bLockedBySelf) {
         m_SerialPortHandler->ResumeSerialPort();
    } // if
}

void LockGuard::Init(std::shared_ptr<SerialPortHandler> a_SerialPortHandler) {
    // Checks
    assert(m_bLockedBySelf == false);
    assert(m_bLockedByOthers == false);
    m_SerialPortHandler = a_SerialPortHandler;
}

void LockGuard::AcquireLock() {
    if (!m_bLockedBySelf) {
        // Increases lock counter, may actually suspend the serial port
        m_bLockedBySelf = true;
        m_SerialPortHandler->SuspendSerialPort();
    } // if
}

void LockGuard::ReleaseLock() {
    if (m_bLockedBySelf) {
        // Decreases lock counter, may actually resume the serial port
        m_bLockedBySelf = false;
        m_SerialPortHandler->ResumeSerialPort();
    } // if
}

bool LockGuard::UpdateSerialPortState(size_t a_LockHolders) {
    // This call is caused by ourselves
    if (m_bLockedBySelf) {
        m_bLockedByOthers = (a_LockHolders > 1);
    } else {
        m_bLockedByOthers = (a_LockHolders > 0);
    } // else
    
    if ((m_bLastLockedBySelf   != m_bLockedBySelf) ||
        (m_bLastLockedByOthers != m_bLockedByOthers)) {
        m_bLastLockedBySelf     = m_bLockedBySelf;
        m_bLastLockedByOthers   = m_bLockedByOthers;
        return true;
    } else {
        return false;
    } // else
}