नेटवर्क पर Qt मेटा सिस्टम। भाग 2 - सिग्नल और स्लॉट

1. संकेत

class DynamicQObject : public QObject { public: DynamicQObject(QObject *mapToObject, const char *signalCatchMethod, QObject *parent = 0); bool addSlot(QObject *object, const char *signal, const QString &slotName); bool removeSlot(const QString &name); bool addSignal(const QString &name, QObject *object, const char *slot); bool removeSignal(const QString &name); bool activate(const QString &signalName, const QVariantList &args); int qt_metacall(QMetaObject::Call call, int id, void **arguments); private: // virtual slots bool containsSlot(const QString &name); QObject *m_mapTo; const char *m_catchMethod; typedef struct { bool isEmpty; // true after removeSlot() QObject *object; int signalIdx; QString name; // virtual slot name QVector<int> parameterTypes; } slot_t; QVector<slot_t> m_slotList; // virtual signals typedef struct { bool isEmpty; // // true after removeSignal() QObject *reciever; int slotIdx; QString name; QVector<int> parameterTypes; } signal_t; QVector<signal_t> m_signalList; QHash<QString, int> m_signalHash; void *m_parameters[11]; // max 10 parameters + ret value }; 

 bool DynamicQObject::addSlot(QObject *object, const char *signal, const QString &slotName) { if (containsSlot(slotName)) return false; if (signal[0] != '2') { qWarning() << "Use SIGNAL() macro"; return false; } 

  QByteArray theSignal = QMetaObject::normalizedSignature(&signal[1]); int signalId = object->metaObject()->indexOfSignal(theSignal); if (signalId < 0) { qWarning() << "signal" << signal << "doesn't exist"; return false; } QVector<int> parameterTypes; QMetaMethod signalMethod = object->metaObject()->method(signalId); for (int i = 0; i < signalMethod.parameterCount(); ++i) parameterTypes.push_back(signalMethod.parameterType(i)); 

  int slotIdx = -1; for (int i = 0; i < m_slotList.count(); ++i) { if (m_slotList[i].isEmpty == true) { slotIdx = i; break; } } bool addEntry = false; if (slotIdx == -1) { addEntry = true; slotIdx = m_slotList.count(); } 

  if (!QMetaObject::connect(object, signalId, this, slotIdx + metaObject()->methodCount())) { qWarning() << "can't connect" << signal << "signal to virtual slot"; return false; } if (addEntry) { m_slotList.push_back({false, object, signalId, slotName, parameterTypes}); } else { slot_t &slot = m_slotList[slotIdx]; slot.isEmpty = false; slot.object = object; slot.signalIdx = signalId; slot.name = slotName; slot.parameterTypes = parameterTypes; } return true; } 

स्लॉट कॉल

 int DynamicQObject::qt_metacall(QMetaObject::Call call, int id, void **arguments) { id = QObject::qt_metacall(call, id, arguments); if (id < 0 || call != QMetaObject::InvokeMetaMethod) return id; Q_ASSERT(id < m_slotList.size()); 

  const slot_t &slotInfo = m_slotList[id]; QVariantList parameters; for (int i = 0; i < slotInfo.parameterTypes.count(); ++i) { void *parameter = arguments[i + 1]; parameters.append(QVariant(slotInfo.parameterTypes[i], parameter)); } 

  QMetaObject::invokeMethod(m_mapTo, m_catchMethod, Q_ARG(QString, slotInfo.name), Q_ARG(QVariantList, parameters)); return -1; } 

 Reciever reciever; DynamicQObject dynamic(&reciever, "signalCatched"); Tester tester; dynamic.addSlot(&tester, SIGNAL(signal1(int,int,QString)), "myslot1"); dynamic.addSlot(&tester, SIGNAL(signal2(QPoint)), "myslot2"); tester.emitSignal1(); tester.emitSingal2(); 

"मैसूरल 1" (QVariant (int, 123), QVariant (int, 456), QVariant (QString, "str"))
मैसूरल 2 (QVariant (QPoint, QPoint (3,4)))

2. स्लॉट

 bool DynamicQObject::addSignal(const QString &name, QObject *object, const char *slot) { if (slot[0] != '1') { qWarning() << "Use SLOT() macro"; return false; } int slotIdx = object->metaObject()-> indexOfSlot(&slot[1]); // without 1 added by SLOT() macro if (slotIdx < 0) { qWarning() << slot << "slot didn't exist"; return false; } 

  QVector<int> parameterTypes; QMetaMethod slotMethod = object->metaObject()->method(slotIdx); for (int i = 0; i < slotMethod.parameterCount(); ++i) parameterTypes.push_back(slotMethod.parameterType(i)); int signalIdx = -1; for (int i = 0; i < m_slotList.count(); ++i) { if (m_slotList[i].isEmpty == true) { signalIdx = i; break; } } bool addEntry = false; if (signalIdx == -1) { addEntry = true; signalIdx = m_signalList.count(); } 

  if (!QMetaObject::connect(this, signalIdx + metaObject()->methodCount(), object, slotIdx)) { qWarning() << "can't connect virtual signal" << name << "to slot" << slot; return false; } if (addEntry) { m_signalList.append({false, object, slotIdx, name, parameterTypes}); } else { signal_t &signal = m_signalList[signalIdx]; signal.isEmpty = false; signal.reciever = object; signal.slotIdx = slotIdx; signal.name = name; signal.parameterTypes = parameterTypes; } m_signalHash.insert(name, signalIdx); return true; } 

संकेत सक्रियण

 bool DynamicQObject::activate(const QString &signalName, const QVariantList &args) { int signalIdx = m_signalHash.value(signalName, -1); if (signalIdx == -1) { qWarning() << "signal" << signalName << "doesn't exist"; return false; } signal_t &signal = m_signalList[signalIdx]; 

  if (args.count() < signal.parameterTypes.count()) { qWarning() << "parameters count mismatch:" << signalName << "provided:" << args.count() << "need >=:" << signal.parameterTypes.count(); return false; } 

  QVariantList argsCopy = args; for (int i = 0; i < signal.parameterTypes.count(); ++i) { if (!argsCopy[i].convert(signal.parameterTypes[i])) { qWarning() << "can't cast parameter" << i << signalName; return false; } m_parameters[i + 1] = argsCopy[i].data(); } 

  DynamicQObject dynamic(&reciever, "signalCatched"); Reciever reciever; dynamic.addSignal("virtual_signal", &reciever, SLOT(slot1(int,QString))); dynamic.activate("virtual_signal", QVariantList() << "123" << QString("qwerty") << 2 << 3); 

slot1_call 123 "मात्रा"