Fixed wrong plugin options behaviour

While working on MR !230 I noticed that the options read I entered into several plugins could not be read after reading the image.

**The patch fixes problems reading options in plugins and adds option checking in the readtest.cpp.**

In particular, the reading test does the following additional actions:
- reads options before reading the image;
- compare the options read with the options returned by the reader after reading the image;
- compares the format and size of the returned image with the format and size returned by the reader.

src/imageformats/exr.cpp

@@ -734,10 +734,12 @@ void EXRHandler::setOption(ImageOption option, const QVariant &value)
 bool EXRHandler::supportsOption(ImageOption option) const
 {
     if (option == QImageIOHandler::Size) {
-        return true;
+        if (auto d = device())
+            return !d->isSequential();
     }
     if (option == QImageIOHandler::ImageFormat) {
-        return true;
+        if (auto d = device())
+            return !d->isSequential();
     }
     if (option == QImageIOHandler::CompressionRatio) {
         return true;
@@ -756,6 +758,9 @@ QVariant EXRHandler::option(ImageOption option) const
         if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
+            if (m_startPos > -1) {
+                d->seek(m_startPos);
+            }
             try {
                 K_IStream istr(d, QByteArray());
                 Imf::RgbaInputFile file(istr);
@@ -778,6 +783,9 @@ QVariant EXRHandler::option(ImageOption option) const
         if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
+            if (m_startPos > -1) {
+                d->seek(m_startPos);
+            }
             try {
                 K_IStream istr(d, QByteArray());
                 Imf::RgbaInputFile file(istr);

src/imageformats/hdr.cpp

@@ -269,13 +269,13 @@ bool HDRHandler::read(QImage *outImage)
 {
     QDataStream s(device());
 
-    QSize size = readHeaderSize(s.device());
-    if (!size.isValid()) {
+    m_imageSize = readHeaderSize(s.device());
+    if (!m_imageSize.isValid()) {
         return false;
     }
 
     QImage img;
-    if (!LoadHDR(s, size.width(), size.height(), img)) {
+    if (!LoadHDR(s, m_imageSize.width(), m_imageSize.height(), img)) {
         // qDebug() << "Error loading HDR file.";
         return false;
     }
@@ -303,7 +303,9 @@ QVariant HDRHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
+        if (!m_imageSize.isEmpty()) {
+            v = QVariant::fromValue(m_imageSize);
+        } else if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto size = readHeaderSize(d);

src/imageformats/hdr_p.h

@@ -22,6 +22,13 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    /*!
+     * \brief m_imageSize
+     * Image size cache used by option()
+     */
+    QSize m_imageSize;
 };
 
 class HDRPlugin : public QImageIOPlugin

src/imageformats/pfm.cpp

@@ -21,7 +21,7 @@
 Q_DECLARE_LOGGING_CATEGORY(LOG_PFMPLUGIN)
 Q_LOGGING_CATEGORY(LOG_PFMPLUGIN, "kf.imageformats.plugins.pfm", QtWarningMsg)
 
-class PfmHeader
+class PFMHeader
 {
 private:
     /*!
@@ -61,7 +61,7 @@ private:
     QDataStream::ByteOrder m_byteOrder;
 
 public:
-    PfmHeader() :
+    PFMHeader() :
         m_bw(false),
         m_ps(false),
         m_width(0),
@@ -157,7 +157,18 @@ public:
     }
 } ;
 
+class PFMHandlerPrivate
+{
+public:
+    PFMHandlerPrivate() {}
+    ~PFMHandlerPrivate() {}
+
+    PFMHeader m_header;
+};
+
 PFMHandler::PFMHandler()
+    : QImageIOHandler()
+    , d(new PFMHandlerPrivate)
 {
 }
 
@@ -177,7 +188,7 @@ bool PFMHandler::canRead(QIODevice *device)
         return false;
     }
 
-    PfmHeader h;
+    PFMHeader h;
     if (!h.peek(device)) {
         return false;
     }
@@ -187,8 +198,7 @@ bool PFMHandler::canRead(QIODevice *device)
 
 bool PFMHandler::read(QImage *image)
 {
-    PfmHeader header;
-
+    auto&& header = d->m_header;
     if (!header.read(device())) {
         qCWarning(LOG_PFMPLUGIN) << "PFMHandler::read() invalid header";
         return false;
@@ -265,27 +275,33 @@ QVariant PFMHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
-            PfmHeader h;
-            if (h.peek(d)) {
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.size());
+        } else if (auto dev = device()) {
+            if (h.peek(dev)) {
                 v = QVariant::fromValue(h.size());
             }
         }
     }
 
     if (option == QImageIOHandler::ImageFormat) {
-        if (auto d = device()) {
-            PfmHeader h;
-            if (h.peek(d)) {
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.format());
+        } else if (auto dev = device()) {
+            if (h.peek(dev)) {
                 v = QVariant::fromValue(h.format());
             }
         }
     }
 
     if (option == QImageIOHandler::Endianness) {
-        if (auto d = device()) {
-            PfmHeader h;
-            if (h.peek(d)) {
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.byteOrder());
+        } else if (auto dev = device()) {
+            if (h.peek(dev)) {
                 v = QVariant::fromValue(h.byteOrder());
             }
         }

src/imageformats/pfm_p.h

@@ -9,7 +9,9 @@
 #define KIMG_PFM_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class PFMHandlerPrivate;
 class PFMHandler : public QImageIOHandler
 {
 public:
@@ -22,6 +24,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<PFMHandlerPrivate> d;
 };
 
 class PFMPlugin : public QImageIOPlugin

src/imageformats/psd.cpp

@@ -112,6 +112,10 @@ enum LayerId : quint32 {
 };
 
 struct PSDHeader {
+    PSDHeader() {
+        memset(this, 0, sizeof(PSDHeader));
+    }
+
     uint signature;
     ushort version;
     uchar reserved[6];
@@ -1375,7 +1379,17 @@ static bool LoadPSD(QDataStream &stream, const PSDHeader &header, QImage &img)
 
 } // Private
 
+class PSDHandlerPrivate
+{
+public:
+    PSDHandlerPrivate() {}
+    ~PSDHandlerPrivate() {}
+    PSDHeader m_header;
+};
+
 PSDHandler::PSDHandler()
+    : QImageIOHandler()
+    , d(new PSDHandlerPrivate)
 {
 }
 
@@ -1393,7 +1407,7 @@ bool PSDHandler::read(QImage *image)
     QDataStream s(device());
     s.setByteOrder(QDataStream::BigEndian);
 
-    PSDHeader header;
+    auto&& header = d->m_header;
     s >> header;
 
     // Check image file format.
@@ -1430,18 +1444,20 @@ QVariant PSDHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
+        auto&& header = d->m_header;
+        if (IsValid(header)) {
+            v = QVariant::fromValue(QSize(header.width, header.height));
+        }
+        else if (auto dev = device()) {
             // transactions works on both random and sequential devices
-            d->startTransaction();
-            auto ba = d->read(sizeof(PSDHeader));
-            d->rollbackTransaction();
+            dev->startTransaction();
+            auto ba = dev->read(sizeof(PSDHeader));
+            dev->rollbackTransaction();
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
 
-            PSDHeader header;
             s >> header;
-
             if (s.status() == QDataStream::Ok && IsValid(header))
                 v = QVariant::fromValue(QSize(header.width, header.height));
         }

src/imageformats/psd_p.h

@@ -9,7 +9,9 @@
 #define KIMG_PSD_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class PSDHandlerPrivate;
 class PSDHandler : public QImageIOHandler
 {
 public:
@@ -22,6 +24,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<PSDHandlerPrivate> d;
 };
 
 class PSDPlugin : public QImageIOPlugin

src/imageformats/pxr.cpp

@@ -15,7 +15,7 @@
 Q_DECLARE_LOGGING_CATEGORY(LOG_PXRPLUGIN)
 Q_LOGGING_CATEGORY(LOG_PXRPLUGIN, "kf.imageformats.plugins.pxr", QtWarningMsg)
 
-class PxrHeader
+class PXRHeader
 {
 private:
     QByteArray m_rawHeader;
@@ -29,7 +29,7 @@ private:
     }
 
 public:
-    PxrHeader()
+    PXRHeader()
     {
 
     }
@@ -139,7 +139,18 @@ public:
     }
 };
 
+class PXRHandlerPrivate
+{
+public:
+    PXRHandlerPrivate() {}
+    ~PXRHandlerPrivate() {}
+
+    PXRHeader m_header;
+};
+
 PXRHandler::PXRHandler()
+    : QImageIOHandler()
+    , d(new PXRHandlerPrivate)
 {
 }
 
@@ -159,7 +170,7 @@ bool PXRHandler::canRead(QIODevice *device)
         return false;
     }
 
-    PxrHeader h;
+    PXRHeader h;
     if (!h.peek(device)) {
         return false;
     }
@@ -169,7 +180,7 @@ bool PXRHandler::canRead(QIODevice *device)
 
 bool PXRHandler::read(QImage *image)
 {
-    PxrHeader header;
+    auto&& header = d->m_header;
 
     if (!header.read(device())) {
         qCWarning(LOG_PXRPLUGIN) << "PXRHandler::read() invalid header";
@@ -217,8 +228,10 @@ QVariant PXRHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
-            PxrHeader h;
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.size());
+        } else if (auto d = device()) {
             if (h.peek(d)) {
                 v = QVariant::fromValue(h.size());
             }
@@ -226,8 +239,10 @@ QVariant PXRHandler::option(ImageOption option) const
     }
 
     if (option == QImageIOHandler::ImageFormat) {
-        if (auto d = device()) {
-            PxrHeader h;
+        auto&& h = d->m_header;
+        if (h.isValid()) {
+            v = QVariant::fromValue(h.format());
+        } else if (auto d = device()) {
             if (h.peek(d)) {
                 v = QVariant::fromValue(h.format());
             }

src/imageformats/pxr_p.h

@@ -9,7 +9,9 @@
 #define KIMG_PXR_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class PXRHandlerPrivate;
 class PXRHandler : public QImageIOHandler
 {
 public:
@@ -22,6 +24,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<PXRHandlerPrivate> d;
 };
 
 class PXRPlugin : public QImageIOPlugin

src/imageformats/qoi.cpp

@@ -31,6 +31,18 @@ namespace // Private
 #define QOI_END_STREAM_PAD 8
 
 struct QoiHeader {
+    QoiHeader()
+        : MagicNumber(0)
+        , Width(0)
+        , Height(0)
+        , Channels(0)
+        , Colorspace(2)
+    {
+    }
+
+    QoiHeader(const QoiHeader&) = default;
+    QoiHeader& operator=(const QoiHeader&) = default;
+
     quint32 MagicNumber;
     quint32 Width;
     quint32 Height;
@@ -297,7 +309,19 @@ static bool SaveQOI(QIODevice *device, const QoiHeader &qoi, const QImage &img)
 
 } // namespace
 
+class QOIHandlerPrivate
+{
+public:
+    QOIHandlerPrivate() {}
+    ~QOIHandlerPrivate() {}
+
+    QoiHeader m_header;
+};
+
+
 QOIHandler::QOIHandler()
+    : QImageIOHandler()
+    , d(new QOIHandlerPrivate)
 {
 }
 
@@ -328,7 +352,7 @@ bool QOIHandler::canRead(QIODevice *device)
 
     QDataStream stream(head);
     stream.setByteOrder(QDataStream::BigEndian);
-    QoiHeader qoi = {0, 0, 0, 0, 2};
+    QoiHeader qoi;
     stream >> qoi;
 
     return IsSupported(qoi);
@@ -340,7 +364,7 @@ bool QOIHandler::read(QImage *image)
     s.setByteOrder(QDataStream::BigEndian);
 
     // Read image header
-    QoiHeader qoi = {0, 0, 0, 0, 2};
+    auto&& qoi = d->m_header;
     s >> qoi;
 
     // Check if file is supported
@@ -402,7 +426,10 @@ QVariant QOIHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(QSize(header.Width, header.Height));
+        } else if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto ba = d->read(sizeof(QoiHeader));
@@ -410,10 +437,7 @@ QVariant QOIHandler::option(ImageOption option) const
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
-
-            QoiHeader header = {0, 0, 0, 0, 2};
             s >> header;
-
             if (s.status() == QDataStream::Ok && IsSupported(header)) {
                 v = QVariant::fromValue(QSize(header.Width, header.Height));
             }
@@ -421,7 +445,10 @@ QVariant QOIHandler::option(ImageOption option) const
     }
 
     if (option == QImageIOHandler::ImageFormat) {
-        if (auto d = device()) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(imageFormat(header));
+        } else if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto ba = d->read(sizeof(QoiHeader));
@@ -429,10 +456,7 @@ QVariant QOIHandler::option(ImageOption option) const
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
-
-            QoiHeader header = {0, 0, 0, 0, 2};
             s >> header;
-
             if (s.status() == QDataStream::Ok && IsSupported(header)) {
                 v = QVariant::fromValue(imageFormat(header));
             }

src/imageformats/qoi_p.h

@@ -9,7 +9,9 @@
 #define KIMG_QOI_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class QOIHandlerPrivate;
 class QOIHandler : public QImageIOHandler
 {
 public:
@@ -23,6 +25,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<QOIHandlerPrivate> d;
 };
 
 class QOIPlugin : public QImageIOPlugin

src/imageformats/ras.cpp

@@ -336,7 +336,19 @@ static bool LoadRAS(QDataStream &s, const RasHeader &ras, QImage &img)
 }
 } // namespace
 
+class RASHandlerPrivate
+{
+public:
+    RASHandlerPrivate() {}
+    ~RASHandlerPrivate() {}
+
+    RasHeader m_header;
+};
+
+
 RASHandler::RASHandler()
+    : QImageIOHandler()
+    , d(new RASHandlerPrivate)
 {
 }
 
@@ -384,7 +396,7 @@ bool RASHandler::read(QImage *outImage)
     s.setByteOrder(QDataStream::BigEndian);
 
     // Read image header.
-    RasHeader ras;
+    auto&& ras = d->m_header;
     s >> ras;
 
     if (ras.ColorMapLength > kMaxQVectorSize) {
@@ -426,18 +438,19 @@ QVariant RASHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(QSize(header.Width, header.Height));
+        }
+        else if (auto dev = device()) {
             // transactions works on both random and sequential devices
-            d->startTransaction();
-            auto ba = d->read(RasHeader::SIZE);
-            d->rollbackTransaction();
+            dev->startTransaction();
+            auto ba = dev->read(RasHeader::SIZE);
+            dev->rollbackTransaction();
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
-
-            RasHeader header;
             s >> header;
-
             if (s.status() == QDataStream::Ok && IsSupported(header)) {
                 v = QVariant::fromValue(QSize(header.Width, header.Height));
             }
@@ -445,18 +458,19 @@ QVariant RASHandler::option(ImageOption option) const
     }
 
     if (option == QImageIOHandler::ImageFormat) {
-        if (auto d = device()) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(imageFormat(header));
+        }
+        else if (auto dev = device()) {
             // transactions works on both random and sequential devices
-            d->startTransaction();
-            auto ba = d->read(RasHeader::SIZE);
-            d->rollbackTransaction();
+            dev->startTransaction();
+            auto ba = dev->read(RasHeader::SIZE);
+            dev->rollbackTransaction();
 
             QDataStream s(ba);
             s.setByteOrder(QDataStream::BigEndian);
-
-            RasHeader header;
             s >> header;
-
             if (s.status() == QDataStream::Ok && IsSupported(header)) {
                 v = QVariant::fromValue(imageFormat(header));
             }

src/imageformats/ras_p.h

@@ -10,7 +10,9 @@
 #define KIMG_RAS_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class RASHandlerPrivate;
 class RASHandler : public QImageIOHandler
 {
 public:
@@ -23,6 +25,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<RASHandlerPrivate> d;
 };
 
 class RASPlugin : public QImageIOPlugin

src/imageformats/tga.cpp

@@ -56,18 +56,18 @@ enum TGAType {
 
 /** Tga Header. */
 struct TgaHeader {
-    uchar id_length;
-    uchar colormap_type;
-    uchar image_type;
-    ushort colormap_index;
-    ushort colormap_length;
-    uchar colormap_size;
-    ushort x_origin;
-    ushort y_origin;
-    ushort width;
-    ushort height;
-    uchar pixel_size;
-    uchar flags;
+    uchar id_length = 0;
+    uchar colormap_type = 0;
+    uchar image_type = 0;
+    ushort colormap_index = 0;
+    ushort colormap_length = 0;
+    uchar colormap_size = 0;
+    ushort x_origin = 0;
+    ushort y_origin = 0;
+    ushort width = 0;
+    ushort height = 0;
+    uchar pixel_size = 0;
+    uchar flags = 0;
 
     enum {
         SIZE = 18,
@@ -407,7 +407,18 @@ static bool LoadTGA(QDataStream &s, const TgaHeader &tga, QImage &img)
 
 } // namespace
 
+class TGAHandlerPrivate
+{
+public:
+    TGAHandlerPrivate() {}
+    ~TGAHandlerPrivate() {}
+
+    TgaHeader m_header;
+};
+
 TGAHandler::TGAHandler()
+    : QImageIOHandler()
+    , d(new TGAHandlerPrivate)
 {
 }
 
@@ -424,20 +435,20 @@ bool TGAHandler::read(QImage *outImage)
 {
     // qDebug() << "Loading TGA file!";
 
-    auto d = device();
-    TgaHeader tga;
-    if (!peekHeader(d, tga) || !IsSupported(tga)) {
+    auto dev = device();
+    auto&& tga = d->m_header;
+    if (!peekHeader(dev, tga) || !IsSupported(tga)) {
         //         qDebug() << "This TGA file is not valid.";
         return false;
     }
 
-    if (d->isSequential()) {
-        d->read(TgaHeader::SIZE + tga.id_length);
+    if (dev->isSequential()) {
+        dev->read(TgaHeader::SIZE + tga.id_length);
     } else {
-        d->seek(TgaHeader::SIZE + tga.id_length);
+        dev->seek(TgaHeader::SIZE + tga.id_length);
     }
 
-    QDataStream s(d);
+    QDataStream s(dev);
     s.setByteOrder(QDataStream::LittleEndian);
 
     // Check image file format.
@@ -519,18 +530,22 @@ QVariant TGAHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
-        if (auto d = device()) {
-            TgaHeader header;
-            if (peekHeader(d, header) && IsSupported(header)) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(QSize(header.width, header.height));
+        } else if (auto dev = device()) {
+            if (peekHeader(dev, header) && IsSupported(header)) {
                 v = QVariant::fromValue(QSize(header.width, header.height));
             }
         }
     }
 
     if (option == QImageIOHandler::ImageFormat) {
-        if (auto d = device()) {
-            TgaHeader header;
-            if (peekHeader(d, header) && IsSupported(header)) {
+        auto&& header = d->m_header;
+        if (IsSupported(header)) {
+            v = QVariant::fromValue(imageFormat(header));
+        } else if (auto dev = device()) {
+            if (peekHeader(dev, header) && IsSupported(header)) {
                 v = QVariant::fromValue(imageFormat(header));
             }
         }

src/imageformats/tga_p.h

@@ -9,7 +9,9 @@
 #define KIMG_TGA_P_H
 
 #include <QImageIOPlugin>
+#include <QScopedPointer>
 
+class TGAHandlerPrivate;
 class TGAHandler : public QImageIOHandler
 {
 public:
@@ -23,6 +25,9 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    const QScopedPointer<TGAHandlerPrivate> d;
 };
 
 class TGAPlugin : public QImageIOPlugin

src/imageformats/xcf.cpp

@@ -4149,7 +4149,9 @@ bool XCFHandler::canRead() const
 bool XCFHandler::read(QImage *image)
 {
     XCFImageFormat xcfif;
-    return xcfif.readXCF(device(), image);
+    auto ok = xcfif.readXCF(device(), image);
+    m_imageSize = image->size();
+    return ok;
 }
 
 bool XCFHandler::write(const QImage &)
@@ -4169,6 +4171,9 @@ QVariant XCFHandler::option(ImageOption option) const
     QVariant v;
 
     if (option == QImageIOHandler::Size) {
+        if (!m_imageSize.isEmpty()) {
+            return m_imageSize;
+        }
         /*
          * The image structure always starts at offset 0 in the XCF file.
          * byte[9]     "gimp xcf " File type identification
@@ -4181,7 +4186,7 @@ QVariant XCFHandler::option(ImageOption option) const
          * uint32      width        Width of canvas
          * uint32      height       Height of canvas
          */
-        if (auto d = device()) {
+        else if (auto d = device()) {
             // transactions works on both random and sequential devices
             d->startTransaction();
             auto ba9 = d->read(9);      // "gimp xcf "

src/imageformats/xcf_p.h

@@ -24,6 +24,13 @@ public:
     QVariant option(QImageIOHandler::ImageOption option) const override;
 
     static bool canRead(QIODevice *device);
+
+private:
+    /*!
+     * \brief m_imageSize
+     * Image size cache used by option()
+     */
+    QSize m_imageSize;
 };
 
 class XCFPlugin : public QImageIOPlugin