QtDebugger/src/signaldumper.cpp

#include "signaldumper.h"

#include <QList>
#include <QMetaObject>
#include <QMetaType>
#include <QMetaMethod>
#include <QObject>
#include <QVariant>

#include <QCoreApplication>
#include <QProcess>
#include <QDebug>

#include <sys/types.h>
#include <sys/stat.h>

static const uint32_t IndentSpacesCount = 4;
static int iLevel = 0;

SignalDumper* SignalDumper::Dumper = nullptr;

static void signalDumperCallback(QObject* caller, int signal_index, void** argv)
{
    Q_ASSERT(caller); Q_ASSERT(argv); Q_UNUSED(argv);
    const QMetaObject *mo = caller->metaObject();
    Q_ASSERT(mo);
    QMetaMethod member = QMetaObjectPrivate::signal(mo, signal_index);
    Q_ASSERT(member.isValid());

    QByteArray str;
    str.fill(' ', iLevel++ * IndentSpacesCount);
    str += "Signal: ";
    str += mo->className();
    str += '(';

    QString objname = caller->objectName();
    str += objname.toLocal8Bit();
    if (!objname.isEmpty())
        str += ' ';
    str += QByteArray::number(quintptr(caller), 16);

    str += ") ";
    str += member.name();
    str += " (";

    QList<QByteArray> args = member.parameterTypes();
    for (int i = 0; i < args.count(); ++i) {
        const QByteArray &arg = args.at(i);
        int typeId = QMetaType::type(args.at(i).constData());
        if (arg.endsWith('*') || arg.endsWith('&')) {
            str += '(';
            str += arg;
            str += ')';
            if (arg.endsWith('&'))
                str += '@';

            quintptr addr = quintptr(*reinterpret_cast<void **>(argv[i + 1]));
            str.append(QByteArray::number(addr, 16));
        } else if (typeId != QMetaType::UnknownType) {
            Q_ASSERT(typeId != QMetaType::Void); // void parameter => metaobject is corrupt
            str.append(arg)
                .append('(')
                .append(QVariant(typeId, argv[i + 1]).toString().toLocal8Bit())
                .append(')');
        }
        str.append(", ");
    }
    if (str.endsWith(", "))
        str.chop(2);
    str.append(')');

    SignalDumper::dumpStr(str);
}

static void signalDumperCallbackSlot(QObject* caller, int method_index, void** argv)
{
    Q_ASSERT(caller); Q_ASSERT(argv); Q_UNUSED(argv);
    const QMetaObject *mo = caller->metaObject();
    Q_ASSERT(mo);
    QMetaMethod member = mo->method(method_index);
    if (!member.isValid())
        return;

    QByteArray str;
    str.fill(' ', iLevel * IndentSpacesCount);
    str += "Slot: ";
    str += mo->className();
    str += '(';

    QString objname = caller->objectName();
    str += objname.toLocal8Bit();
    if (!objname.isEmpty())
        str += ' ';
    str += QByteArray::number(quintptr(caller), 16);

    str += ") ";
    str += member.methodSignature();

    SignalDumper::dumpStr(str);
}

static void signalDumperCallbackEndSignal(QObject* caller, int /*signal_index*/)
{
    Q_ASSERT(caller); Q_ASSERT(caller->metaObject());
    --iLevel;
    Q_ASSERT(iLevel >= 0);
}

void SignalDumper::dumpStr(QString str) {
    if(Dumper) {
        Dumper->dump(str);
    }
}

SignalDumper::SignalDumper(QObject* parent) : QObject(parent) {}

SignalDumper::~SignalDumper() {
    if(Dumper == this) {
        endDump();
    }
}

void SignalDumper::startDump()
{
    if(Dumper) {
        return;
    }
    Dumper = this;

    // mkfifo
    QString fifoName = "/tmp/signalLogger." + QString::number(QCoreApplication::applicationPid());
    QByteArray fifoNameArr = fifoName.toLocal8Bit();
    if(::mkfifo(fifoNameArr.data(), 0700)) {
        qCritical() << "could not create fifo" << errno;
    }

    // make process
    displayProc = new QProcess(this);
    displayProc->start("gnome-terminal", { "--", "cat", fifoName });

    if(fifo) {
        fifo->deleteLater();
    }

    fifo = new QFile(fifoName);
    fifo->open(QIODevice::WriteOnly);

    iLevel = 0;

    // start listening
    static QSignalSpyCallbackSet set = { signalDumperCallback,
        signalDumperCallbackSlot, signalDumperCallbackEndSignal, 0 };
    registerCall(set);
}

void SignalDumper::endDump()
{
    if(Dumper != this) {
        return;
    }

    // stop listening
    static QSignalSpyCallbackSet nset = { 0, 0, 0 ,0 };
    registerCall(nset);

    // kill process
    displayProc->terminate();
    displayProc->deleteLater();

    // del fifo
    fifo->remove();

    Dumper = nullptr;
}

void SignalDumper::dump(QString str) {
    str += '\n';
    QByteArray arr = str.toLocal8Bit();
    fifo->write(arr);
    fifo->flush();
}