Introduce QPrintDevice::property/setProperty

So we can access QPlatformPrintDevice internals if needed

Change-Id: Ib37c5717713f37262ef12d7b61793d80f05baf4a
Reviewed-by: Liang Qi <liang.qi@qt.io>

src/printsupport/kernel/qplatformprintdevice.cpp

@@ -381,6 +381,21 @@ void QPlatformPrintDevice::loadMimeTypes() const
 {
 }
 
+QVariant QPlatformPrintDevice::property(QPrintDevice::PrintDevicePropertyKey key) const
+{
+    Q_UNUSED(key)
+
+    return QVariant();
+}
+
+bool QPlatformPrintDevice::setProperty(QPrintDevice::PrintDevicePropertyKey key, const QVariant &value)
+{
+    Q_UNUSED(key)
+    Q_UNUSED(value)
+
+    return false;
+}
+
 QList<QMimeType> QPlatformPrintDevice::supportedMimeTypes() const
 {
     if (!m_haveMimeTypes)

src/printsupport/kernel/qplatformprintdevice.h

@@ -53,11 +53,14 @@
 
 #include <QtPrintSupport/qtprintsupportglobal.h>
 #include <private/qprint_p.h>
+#include <private/qprintdevice_p.h>
 
+#include <QtCore/qvariant.h>
 #include <QtCore/qvector.h>
 #include <QtCore/qmimetype.h>
 #include <QtGui/qpagelayout.h>
 
+
 QT_BEGIN_NAMESPACE
 
 #ifndef QT_NO_PRINTER
@@ -118,6 +121,9 @@ public:
     virtual QPrint::ColorMode defaultColorMode() const;
     virtual QList<QPrint::ColorMode> supportedColorModes() const;
 
+    virtual QVariant property(QPrintDevice::PrintDevicePropertyKey key) const;
+    virtual bool setProperty(QPrintDevice::PrintDevicePropertyKey key, const QVariant &value);
+
 #ifndef QT_NO_MIMETYPE
     virtual QList<QMimeType> supportedMimeTypes() const;
 #endif

src/printsupport/kernel/qprintdevice.cpp

@@ -245,6 +245,16 @@ QList<QPrint::ColorMode> QPrintDevice::supportedColorModes() const
     return isValid() ? d->supportedColorModes() : QList<QPrint::ColorMode>();
 }
 
+QVariant QPrintDevice::property(PrintDevicePropertyKey key) const
+{
+    return isValid() ? d->property(key) : QVariant();
+}
+
+bool QPrintDevice::setProperty(PrintDevicePropertyKey key, const QVariant &value)
+{
+    return isValid() ? d->setProperty(key, value) : false;
+}
+
 #ifndef QT_NO_MIMETYPE
 QList<QMimeType> QPrintDevice::supportedMimeTypes() const
 {

src/printsupport/kernel/qprintdevice_p.h

@@ -131,6 +131,13 @@ public:
     QPrint::ColorMode defaultColorMode() const;
     QList<QPrint::ColorMode> supportedColorModes() const;
 
+    enum PrintDevicePropertyKey {
+        PDPK_CustomBase = 0xff00
+    };
+
+    QVariant property(PrintDevicePropertyKey key) const;
+    bool setProperty(PrintDevicePropertyKey key, const QVariant &value);
+
 #ifndef QT_NO_MIMETYPE
     QList<QMimeType> supportedMimeTypes() const;
 #endif