Clean up code that handle clipboard image conversion on Windows

This commit remove old legacy code that try to deal with clipboard
image conversion in the qwindowsmime class. It now uses
qbmphandler under the hood which is much more complete.
It also add a small fix for the conversion
of BI_RGB clipboard image with an explicit alpha layer (which Firefox
use on Windows).

Change-Id: Iae026378831799dc676e1aba7d5bd6a0d1c01e7f
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Eirik Aavitsland <eirik.aavitsland@qt.io>

1 files changed, 14 insertions, 126 deletions

diff --git a/src/plugins/platforms/windows/qwindowsmime.cpp b/src/plugins/platforms/windows/qwindowsmime.cpp
index 95c9a890ef..3321845411 100644
--- a/src/plugins/platforms/windows/qwindowsmime.cpp
+++ b/src/plugins/platforms/windows/qwindowsmime.cpp
@@ -114,16 +114,15 @@ static inline QByteArray msgConversionError(const char *func, const char *format
     return msg;
 }
 
-static inline QImage readDib(QByteArray data)
+static inline bool readDib(QBuffer &buffer, QImage &img)
 {
-    QBuffer buffer(&data);
-    buffer.open(QIODevice::ReadOnly);
     QImageReader reader(&buffer, dibFormatC);
     if (!reader.canRead()) {
-         qWarning("%s", msgConversionError(__FUNCTION__, dibFormatC).constData());
-         return QImage();
+        qWarning("%s", msgConversionError(__FUNCTION__, dibFormatC).constData());
+        return false;
     }
-    return reader.read();
+    img = reader.read();
+    return true;
 }
 
 static QByteArray writeDib(const QImage &img)
@@ -213,94 +212,6 @@ static bool qt_write_dibv5(QDataStream &s, QImage image)
     return true;
 }
 
-static int calc_shift(int mask)
-{
-    int result = 0;
-    while (!(mask & 1)) {
-        result++;
-        mask >>= 1;
-    }
-    return result;
-}
-
-//Supports only 32 bit DIBV5
-static bool qt_read_dibv5(QDataStream &s, QImage &image)
-{
-    BMP_BITMAPV5HEADER bi;
-    QIODevice* d = s.device();
-    if (d->atEnd())
-        return false;
-
-    d->read(reinterpret_cast<char *>(&bi), sizeof(bi));   // read BITMAPV5HEADER header
-    if (s.status() != QDataStream::Ok)
-        return false;
-
-    const int nbits = bi.bV5BitCount;
-    if (nbits != 32 || bi.bV5Planes != 1 || bi.bV5Compression != BMP_BITFIELDS)
-        return false; //Unsupported DIBV5 format
-
-    const int w = bi.bV5Width;
-    int h = bi.bV5Height;
-    const int red_mask = int(bi.bV5RedMask);
-    const int green_mask = int(bi.bV5GreenMask);
-    const int blue_mask = int(bi.bV5BlueMask);
-    const int alpha_mask = int(bi.bV5AlphaMask);
-
-    const QImage::Format format = QImage::Format_ARGB32;
-
-    if (bi.bV5Height < 0)
-        h = -h;     // support images with negative height
-    if (image.size() != QSize(w, h) || image.format() != format) {
-        image = QImage(w, h, format);
-        if (image.isNull())     // could not create image
-            return false;
-    }
-    image.setDotsPerMeterX(bi.bV5XPelsPerMeter);
-    image.setDotsPerMeterY(bi.bV5YPelsPerMeter);
-
-    const int red_shift = calc_shift(red_mask);
-    const int green_shift = calc_shift(green_mask);
-    const int blue_shift = calc_shift(blue_mask);
-    const int alpha_shift =  alpha_mask ? calc_shift(alpha_mask) : 0u;
-
-    const qsizetype  bpl = image.bytesPerLine();
-    uchar *data = image.bits();
-
-    auto *buf24 = new uchar[bpl];
-    const qsizetype bpl24 = ((qsizetype(w) * nbits + 31) / 32) * 4;
-
-    while (--h >= 0) {
-        QRgb *p = reinterpret_cast<QRgb *>(data + h * bpl);
-        QRgb *end = p + w;
-        if (d->read(reinterpret_cast<char *>(buf24), bpl24) != bpl24)
-            break;
-        const uchar *b = buf24;
-        while (p < end) {
-            const int c = *b | (*(b + 1)) << 8 | (*(b + 2)) << 16 | (*(b + 3)) << 24;
-            *p++ = qRgba(((c & red_mask) >> red_shift) ,
-                                    ((c & green_mask) >> green_shift),
-                                    ((c & blue_mask) >> blue_shift),
-                                    ((c & alpha_mask) >> alpha_shift));
-            b += 4;
-        }
-    }
-    delete[] buf24;
-
-    if (bi.bV5Height < 0) {
-        // Flip the image
-        auto *buf = new uchar[bpl];
-        h = -bi.bV5Height;
-        for (int y = 0; y < h/2; ++y) {
-            memcpy(buf, data + y * bpl, size_t(bpl));
-            memcpy(data + y*bpl, data + (h - y -1) * bpl, size_t(bpl));
-            memcpy(data + (h - y -1 ) * bpl, buf, size_t(bpl));
-        }
-        delete [] buf;
-    }
-
-    return true;
-}
-
 // helpers for using global memory
 
 static int getCf(const FORMATETC &formatetc)
@@ -1018,7 +929,6 @@ public:
     QVariant convertToMime(const QString &mime, IDataObject *pDataObj, QMetaType preferredType) const override;
     QString mimeForFormat(const FORMATETC &formatetc) const override;
 private:
-    bool hasOriginalDIBV5(IDataObject *pDataObj) const;
     UINT CF_PNG;
 };
 
@@ -1100,44 +1010,20 @@ bool QWindowsMimeImage::convertFromMime(const FORMATETC &formatetc, const QMimeD
     return false;
 }
 
-bool QWindowsMimeImage::hasOriginalDIBV5(IDataObject *pDataObj) const
-{
-    bool isSynthesized = true;
-    IEnumFORMATETC *pEnum = nullptr;
-    HRESULT res = pDataObj->EnumFormatEtc(1, &pEnum);
-    if (res == S_OK && pEnum) {
-        FORMATETC fc;
-        while ((res = pEnum->Next(1, &fc, nullptr)) == S_OK) {
-            if (fc.ptd)
-                CoTaskMemFree(fc.ptd);
-            if (fc.cfFormat == CF_DIB)
-                break;
-            if (fc.cfFormat == CF_DIBV5) {
-                isSynthesized  = false;
-                break;
-            }
-        }
-        pEnum->Release();
-    }
-    return !isSynthesized;
-}
-
 QVariant QWindowsMimeImage::convertToMime(const QString &mimeType, IDataObject *pDataObj, QMetaType preferredType) const
 {
     Q_UNUSED(preferredType);
     QVariant result;
     if (mimeType != u"application/x-qt-image")
         return result;
-    //Try to convert from a format which has more data
-    //DIBV5, use only if its is not synthesized
-    if (canGetData(CF_DIBV5, pDataObj) && hasOriginalDIBV5(pDataObj)) {
+    //Try to convert from DIBV5 as it is the most
+    //widespread format that support transparency
+    if (canGetData(CF_DIBV5, pDataObj)) {
         QImage img;
         QByteArray data = getData(CF_DIBV5, pDataObj);
-        QDataStream s(&data, QIODevice::ReadOnly);
-        s.setByteOrder(QDataStream::LittleEndian);
-        if (qt_read_dibv5(s, img)) { // #### supports only 32bit DIBV5
+        QBuffer buffer(&data);
+        if (readDib(buffer, img))
             return img;
-        }
     }
     //PNG, MS Office place this (undocumented)
     if (canGetData(CF_PNG, pDataObj)) {
@@ -1149,8 +1035,10 @@ QVariant QWindowsMimeImage::convertToMime(const QString &mimeType, IDataObject *
     }
     //Fallback to DIB
     if (canGetData(CF_DIB, pDataObj)) {
-        const QImage img = readDib(getData(CF_DIB, pDataObj));
-        if (!img.isNull())
+        QImage img;
+        QByteArray data = getData(CF_DIBV5, pDataObj);
+        QBuffer buffer(&data);
+        if (readDib(buffer, img))
             return img;
     }
     // Failed