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Qt源码分析--QObject(2)
2022-06-24 07:01:00 【天天进步2015】
1.boolblockSignals(bool b) noexcept;
bool QObject::blockSignals(bool block) noexcept
{
Q_D(QObject);
bool previous = d->blockSig;
d->blockSig = block;
return previous;
}2.children()
inline const QObjectList &children() const { return d_ptr->children; }
3.staticQMetaObject::Connectionconnect(constQObject *sender, constchar *signal,constQObject *receiver, constchar *member, Qt::ConnectionType = Qt::AutoConnection);
QMetaObject::Connection QObject::connect(const QObject *sender, const char *signal,
const QObject *receiver, const char *method,
Qt::ConnectionType type)
{
if (sender == 0 || receiver == 0 || signal == 0 || method == 0) {
qWarning("QObject::connect: Cannot connect %s::%s to %s::%s",
sender ? sender->metaObject()->className() : "(null)",
(signal && *signal) ? signal+1 : "(null)",
receiver ? receiver->metaObject()->className() : "(null)",
(method && *method) ? method+1 : "(null)");
return QMetaObject::Connection(0);
}
QByteArray tmp_signal_name;
if (!check_signal_macro(sender, signal, "connect", "bind"))
return QMetaObject::Connection(0);
const QMetaObject *smeta = sender->metaObject();
const char *signal_arg = signal;
++signal; //skip code
QArgumentTypeArray signalTypes;
Q_ASSERT(QMetaObjectPrivate::get(smeta)->revision >= 7);
QByteArray signalName = QMetaObjectPrivate::decodeMethodSignature(signal, signalTypes);
int signal_index = QMetaObjectPrivate::indexOfSignalRelative(
&smeta, signalName, signalTypes.size(), signalTypes.constData());
if (signal_index < 0) {
// check for normalized signatures
tmp_signal_name = QMetaObject::normalizedSignature(signal - 1);
signal = tmp_signal_name.constData() + 1;
signalTypes.clear();
signalName = QMetaObjectPrivate::decodeMethodSignature(signal, signalTypes);
smeta = sender->metaObject();
signal_index = QMetaObjectPrivate::indexOfSignalRelative(
&smeta, signalName, signalTypes.size(), signalTypes.constData());
}
if (signal_index < 0) {
err_method_notfound(sender, signal_arg, "connect");
err_info_about_objects("connect", sender, receiver);
return QMetaObject::Connection(0);
}
signal_index = QMetaObjectPrivate::originalClone(smeta, signal_index);
signal_index += QMetaObjectPrivate::signalOffset(smeta);
QByteArray tmp_method_name;
int membcode = extract_code(method);
if (!check_method_code(membcode, receiver, method, "connect"))
return QMetaObject::Connection(0);
const char *method_arg = method;
++method; // skip code
QArgumentTypeArray methodTypes;
QByteArray methodName = QMetaObjectPrivate::decodeMethodSignature(method, methodTypes);
const QMetaObject *rmeta = receiver->metaObject();
int method_index_relative = -1;
Q_ASSERT(QMetaObjectPrivate::get(rmeta)->revision >= 7);
switch (membcode) {
case QSLOT_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSlotRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
case QSIGNAL_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSignalRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
}
if (method_index_relative < 0) {
// check for normalized methods
tmp_method_name = QMetaObject::normalizedSignature(method);
method = tmp_method_name.constData();
methodTypes.clear();
methodName = QMetaObjectPrivate::decodeMethodSignature(method, methodTypes);
// rmeta may have been modified above
rmeta = receiver->metaObject();
switch (membcode) {
case QSLOT_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSlotRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
case QSIGNAL_CODE:
method_index_relative = QMetaObjectPrivate::indexOfSignalRelative(
&rmeta, methodName, methodTypes.size(), methodTypes.constData());
break;
}
}
if (method_index_relative < 0) {
err_method_notfound(receiver, method_arg, "connect");
err_info_about_objects("connect", sender, receiver);
return QMetaObject::Connection(0);
}
if (!QMetaObjectPrivate::checkConnectArgs(signalTypes.size(), signalTypes.constData(),
methodTypes.size(), methodTypes.constData())) {
qWarning("QObject::connect: Incompatible sender/receiver arguments"
"\n %s::%s --> %s::%s",
sender->metaObject()->className(), signal,
receiver->metaObject()->className(), method);
return QMetaObject::Connection(0);
}
int *types = 0;
if ((type == Qt::QueuedConnection)
&& !(types = queuedConnectionTypes(signalTypes.constData(), signalTypes.size()))) {
return QMetaObject::Connection(0);
}
#ifndef QT_NO_DEBUG
QMetaMethod smethod = QMetaObjectPrivate::signal(smeta, signal_index);
QMetaMethod rmethod = rmeta->method(method_index_relative + rmeta->methodOffset());
check_and_warn_compat(smeta, smethod, rmeta, rmethod);
#endif
QMetaObject::Connection handle = QMetaObject::Connection(QMetaObjectPrivate::connect(
sender, signal_index, smeta, receiver, method_index_relative, rmeta ,type, types));
return handle;
}
static bool check_signal_macro(const QObject *sender, const char *signal,
const char *func, const char *op)
{
int sigcode = extract_code(signal);
if (sigcode != QSIGNAL_CODE) {
if (sigcode == QSLOT_CODE)
qWarning("QObject::%s: Attempt to %s non-signal %s::%s",
func, op, sender->metaObject()->className(), signal+1);
else
qWarning("QObject::%s: Use the SIGNAL macro to %s %s::%s",
func, op, sender->metaObject()->className(), signal);
return false;
}
return true;
}
//把signal从字符转成整型数
static int extract_code(const char *member)
{
// extract code, ensure QMETHOD_CODE <= code <= QSIGNAL_CODE
return (((int)(*member) - '0') & 0x3);
}
//解析signal签名
QByteArray QMetaObjectPrivate::decodeMethodSignature(
const char *signature, QArgumentTypeArray &types)
{
Q_ASSERT(signature != 0);
const char *lparens = strchr(signature, '(');
if (!lparens)
return QByteArray();
const char *rparens = strrchr(lparens + 1, ')');
if (!rparens || *(rparens+1))
return QByteArray();
int nameLength = lparens - signature;
argumentTypesFromString(lparens + 1, rparens, types);
return QByteArray::fromRawData(signature, nameLength);
}
//返回signal的index
int QMetaObjectPrivate::indexOfSignalRelative(const QMetaObject **baseObject,
const QByteArray &name, int argc,
const QArgumentType *types)
{
int i = indexOfMethodRelative<MethodSignal>(baseObject, name, argc, types);
#ifndef QT_NO_DEBUG
const QMetaObject *m = *baseObject;
if (i >= 0 && m && m->d.superdata) {
int conflict = indexOfMethod(m->d.superdata, name, argc, types);
if (conflict >= 0) {
QMetaMethod conflictMethod = m->d.superdata->method(conflict);
qWarning("QMetaObject::indexOfSignal: signal %s from %s redefined in %s",
conflictMethod.methodSignature().constData(),
objectClassName(m->d.superdata), objectClassName(m));
}
}
#endif
return i;
}
//如果 local_method_index 是克隆方法，则返回原始方法的索引。
int QMetaObjectPrivate::originalClone(const QMetaObject *mobj, int local_method_index)
{
Q_ASSERT(local_method_index < get(mobj)->methodCount);
int handle = get(mobj)->methodData + 5 * local_method_index;
while (mobj->d.data[handle + 4] & MethodCloned) {
Q_ASSERT(local_method_index > 0);
handle -= 5;
local_method_index--;
}
return local_method_index;
}
int QMetaObjectPrivate::signalOffset(const QMetaObject *m)
{
Q_ASSERT(m != 0);
int offset = 0;
for (m = m->d.superdata; m; m = m->d.superdata)
offset += priv(m->d.data)->signalCount;
return offset;
}
static int extract_code(const char *member)
{
// extract code, ensure QMETHOD_CODE <= code <= QSIGNAL_CODE
return (((int)(*member) - '0') & 0x3);
}
static bool check_method_code(int code, const QObject *object,
const char *method, const char *func)
{
if (code != QSLOT_CODE && code != QSIGNAL_CODE) {
qWarning("QObject::%s: Use the SLOT or SIGNAL macro to "
"%s %s::%s", func, func, object->metaObject()->className(), method);
return false;
}
return true;
}
//如果 signalTypes 和 methodTypes 是兼容的，则返回true
; 否则返回false
bool QMetaObjectPrivate::checkConnectArgs(int signalArgc, const QArgumentType *signalTypes,
int methodArgc, const QArgumentType *methodTypes)
{
if (signalArgc < methodArgc)
return false;
for (int i = 0; i < methodArgc; ++i) {
if (signalTypes[i] != methodTypes[i])
return false;
}
return true;
}
static int *queuedConnectionTypes(const QArgumentType *argumentTypes, int argc)
{
QScopedArrayPointer<int> types(new int [argc + 1]);
for (int i = 0; i < argc; ++i) {
const QArgumentType &type = argumentTypes[i];
if (type.type())
types[i] = type.type();
else if (type.name().endsWith('*'))
types[i] = QMetaType::VoidStar;
else
types[i] = QMetaType::type(type.name());
if (!types[i]) {
qWarning("QObject::connect: Cannot queue arguments of type '%s'\n"
"(Make sure '%s' is registered using qRegisterMetaType().)",
type.name().constData(), type.name().constData());
return 0;
}
}
types[argc] = 0;
return types.take();
}
QObjectPrivate::Connection *QMetaObjectPrivate::connect(const QObject *sender,
int signal_index, const QMetaObject *smeta,
const QObject *receiver, int method_index,
const QMetaObject *rmeta, int type, int *types)
{
QObject *s = const_cast<QObject *>(sender);
QObject *r = const_cast<QObject *>(receiver);
int method_offset = rmeta ? rmeta->methodOffset() : 0;
Q_ASSERT(!rmeta || QMetaObjectPrivate::get(rmeta)->revision >= 6);
QObjectPrivate::StaticMetaCallFunction callFunction = rmeta ? rmeta->d.static_metacall : nullptr;
QOrderedMutexLocker locker(signalSlotLock(sender),
signalSlotLock(receiver));
QObjectPrivate::ConnectionData *scd = QObjectPrivate::get(s)->connections.loadRelaxed();
if (type & Qt::UniqueConnection && scd) {
if (scd->signalVectorCount() > signal_index) {
const QObjectPrivate::Connection *c2 = scd->signalVector.loadRelaxed()->at(signal_index).first.loadRelaxed();
int method_index_absolute = method_index + method_offset;
while (c2) {
if (!c2->isSlotObject && c2->receiver.loadRelaxed() == receiver && c2->method() == method_index_absolute)
return nullptr;
c2 = c2->nextConnectionList.loadRelaxed();
}
}
type &= Qt::UniqueConnection - 1;
}
std::unique_ptr<QObjectPrivate::Connection> c{new QObjectPrivate::Connection};
c->sender = s;
c->signal_index = signal_index;
c->receiver.storeRelaxed(r);
QThreadData *td = r->d_func()->threadData;
td->ref();
c->receiverThreadData.storeRelaxed(td);
c->method_relative = method_index;
c->method_offset = method_offset;
c->connectionType = type;
c->isSlotObject = false;
c->argumentTypes.storeRelaxed(types);
c->callFunction = callFunction;
QObjectPrivate::get(s)->addConnection(signal_index, c.get());
locker.unlock();
QMetaMethod smethod = QMetaObjectPrivate::signal(smeta, signal_index);
if (smethod.isValid())
s->connectNotify(smethod);
return c.release();
}check_signal_macro()函数检查signal是不是信号。
整个流程如下:
1.先检查输入参数是否正确
2.然后遍历slots函数，检查是否存在。
3.最后生成一个connection返回。
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