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#include <private/qcocoaintrospection_p.h>

QT_BEGIN_NAMESPACE

void qt_cocoa_change_implementation(Class baseClass, SEL originalSel, Class proxyClass, SEL replacementSel, SEL backupSel)
{
#ifndef QT_MAC_USE_COCOA
    if (QSysInfo::MacintoshVersion >= QSysInfo::MV_10_5)
#endif
    {
#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
        // The following code replaces the _implementation_ for the selector we want to hack
        // (originalSel) with the implementation found in proxyClass. Then it creates
        // a new 'backup' method inside baseClass containing the old, original,
        // implementation (fakeSel). You can let the proxy implementation of originalSel
        // call fakeSel if needed (similar approach to calling a super class implementation).
        // fakeSel must also be implemented in proxyClass, as the signature is used
        // as template for the method one we add into baseClass.
        // NB: You will typically never create any instances of proxyClass; we use it
        // only for stealing its contents and put it into baseClass.
        if (!replacementSel)
            replacementSel = originalSel;

        Method originalMethod = class_getInstanceMethod(baseClass, originalSel);
        Method replacementMethod = class_getInstanceMethod(proxyClass, replacementSel);
        IMP originalImp = method_setImplementation(originalMethod, method_getImplementation(replacementMethod));

        if (backupSel) {
            Method backupMethod = class_getInstanceMethod(proxyClass, backupSel);
            class_addMethod(baseClass, backupSel, originalImp, method_getTypeEncoding(backupMethod));
        }
#endif
    }
}

void qt_cocoa_change_back_implementation(Class baseClass, SEL originalSel, SEL backupSel)
{
#ifndef QT_MAC_USE_COCOA
    if (QSysInfo::MacintoshVersion >= QSysInfo::MV_10_5)
#endif
    {
#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
        Method originalMethod = class_getInstanceMethod(baseClass, originalSel);
        Method backupMethodInBaseClass = class_getInstanceMethod(baseClass, backupSel);
        method_setImplementation(originalMethod, method_getImplementation(backupMethodInBaseClass));
#endif
    }
}

QT_END_NAMESPACE
