QColorSpace: port to QESDP

Replace the hand-rolled refcount management with QESDP.
Since the class has a default-constructed / moved-from state
where the d-pointer can be nullptr, add a in-class detach() that
ensures a private object.

Change-Id: Id81431fa60132dbc0eed45bb60b38d4f7d73833f
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>

5 files changed, 42 insertions, 61 deletions

diff --git a/src/gui/image/qpnghandler.cpp b/src/gui/image/qpnghandler.cpp
index 6c05e0a567..de913af320 100644
--- a/src/gui/image/qpnghandler.cpp
+++ b/src/gui/image/qpnghandler.cpp
@@ -592,7 +592,7 @@ bool QPngHandlerPrivate::readPngHeader()
         if (!colorSpace.isValid()) {
             qCWarning(lcImageIo) << "QPngHandler: Failed to parse ICC profile";
         } else {
-            QColorSpacePrivate *csD = QColorSpacePrivate::getWritable(colorSpace);
+            QColorSpacePrivate *csD = QColorSpacePrivate::get(colorSpace);
             if (csD->description.isEmpty())
                 csD->description = QString::fromLatin1((const char *)name);
             colorSpaceState = Icc;
diff --git a/src/gui/painting/qcolorspace.cpp b/src/gui/painting/qcolorspace.cpp
index baaac8b46d..a4ae294793 100644
--- a/src/gui/painting/qcolorspace.cpp
+++ b/src/gui/painting/qcolorspace.cpp
@@ -423,11 +423,10 @@ QColorTransform QColorSpacePrivate::transformationToColorSpace(const QColorSpace
 */
 
 /*!
+    \fn QColorSpace::QColorSpace()
+
     Creates a new colorspace object that represents an undefined and invalid colorspace.
  */
-QColorSpace::QColorSpace()
-{
-}
 
 /*!
     Creates a new colorspace object that represents a \a namedColorSpace.
@@ -450,7 +449,6 @@ QColorSpace::QColorSpace(NamedColorSpace namedColorSpace)
             delete tmp;
     }
     d_ptr = cspriv;
-    d_ptr->ref.ref();
     Q_ASSERT(isValid());
 }
 
@@ -461,7 +459,6 @@ QColorSpace::QColorSpace(NamedColorSpace namedColorSpace)
 QColorSpace::QColorSpace(QColorSpace::Primaries primaries, QColorSpace::TransferFunction fun, float gamma)
         : d_ptr(new QColorSpacePrivate(primaries, fun, gamma))
 {
-    d_ptr->ref.ref();
 }
 
 /*!
@@ -471,7 +468,6 @@ QColorSpace::QColorSpace(QColorSpace::Primaries primaries, QColorSpace::Transfer
 QColorSpace::QColorSpace(QColorSpace::Primaries primaries, float gamma)
         : d_ptr(new QColorSpacePrivate(primaries, TransferFunction::Gamma, gamma))
 {
-    d_ptr->ref.ref();
 }
 
 /*!
@@ -485,36 +481,16 @@ QColorSpace::QColorSpace(const QPointF &whitePoint, const QPointF &redPoint,
     QColorSpacePrimaries primaries(whitePoint, redPoint, greenPoint, bluePoint);
     if (!primaries.areValid()) {
         qWarning() << "QColorSpace attempted constructed from invalid primaries:" << whitePoint << redPoint << greenPoint << bluePoint;
-        d_ptr = nullptr;
         return;
     }
     d_ptr = new QColorSpacePrivate(primaries, fun, gamma);
-    d_ptr->ref.ref();
 }
 
-QColorSpace::~QColorSpace()
-{
-    if (d_ptr && !d_ptr->ref.deref())
-        delete d_ptr;
-}
+QColorSpace::~QColorSpace() = default;
 
-QColorSpace::QColorSpace(const QColorSpace &colorSpace)
-        : d_ptr(colorSpace.d_ptr)
-{
-    if (d_ptr)
-        d_ptr->ref.ref();
-}
+QT_DEFINE_QESDP_SPECIALIZATION_DTOR(QColorSpacePrivate)
 
-QColorSpace &QColorSpace::operator=(const QColorSpace &colorSpace)
-{
-    QColorSpacePrivate *oldD = d_ptr;
-    d_ptr = colorSpace.d_ptr;
-    if (d_ptr)
-        d_ptr->ref.ref();
-    if (oldD && !oldD->ref.deref())
-        delete oldD;
-    return *this;
-}
+QColorSpace::QColorSpace(const QColorSpace &colorSpace) noexcept = default;
 
 /*! \fn void QColorSpace::swap(QColorSpace &other)
 
@@ -571,12 +547,11 @@ void QColorSpace::setTransferFunction(QColorSpace::TransferFunction transferFunc
         return;
     if (!d_ptr) {
         d_ptr = new QColorSpacePrivate(Primaries::Custom, transferFunction, gamma);
-        d_ptr->ref.ref();
         return;
     }
     if (d_ptr->transferFunction == transferFunction && d_ptr->gamma == gamma)
         return;
-    QColorSpacePrivate::getWritable(*this);  // detach
+    detach();
     d_ptr->description.clear();
     d_ptr->transferFunction = transferFunction;
     d_ptr->gamma = gamma;
@@ -612,12 +587,11 @@ void QColorSpace::setPrimaries(QColorSpace::Primaries primariesId)
         return;
     if (!d_ptr) {
         d_ptr = new QColorSpacePrivate(primariesId, TransferFunction::Custom, 0.0f);
-        d_ptr->ref.ref();
         return;
     }
     if (d_ptr->primaries == primariesId)
         return;
-    QColorSpacePrivate::getWritable(*this);  // detach
+    detach();
     d_ptr->description.clear();
     d_ptr->primaries = primariesId;
     d_ptr->identifyColorSpace();
@@ -638,13 +612,12 @@ void QColorSpace::setPrimaries(const QPointF &whitePoint, const QPointF &redPoin
         return;
     if (!d_ptr) {
         d_ptr = new QColorSpacePrivate(primaries, TransferFunction::Custom, 0.0f);
-        d_ptr->ref.ref();
         return;
     }
     QColorMatrix toXyz = primaries.toXyzMatrix();
     if (QColorVector(primaries.whitePoint) == d_ptr->whitePoint && toXyz == d_ptr->toXyz)
         return;
-    QColorSpacePrivate::getWritable(*this);  // detach
+    detach();
     d_ptr->description.clear();
     d_ptr->primaries = QColorSpace::Primaries::Custom;
     d_ptr->toXyz = toXyz;
@@ -653,6 +626,17 @@ void QColorSpace::setPrimaries(const QPointF &whitePoint, const QPointF &redPoin
 }
 
 /*!
+    \internal
+*/
+void QColorSpace::detach()
+{
+    if (d_ptr)
+        d_ptr.detach();
+    else
+        d_ptr = new QColorSpacePrivate;
+}
+
+/*!
     Returns an ICC profile representing the color space.
 
     If the color space was generated from an ICC profile, that profile
@@ -691,8 +675,8 @@ QColorSpace QColorSpace::fromIccProfile(const QByteArray &iccProfile)
     QColorSpace colorSpace;
     if (QIcc::fromIccProfile(iccProfile, &colorSpace))
         return colorSpace;
-    QColorSpacePrivate *d = QColorSpacePrivate::getWritable(colorSpace);
-    d->iccProfile = iccProfile;
+    colorSpace.detach();
+    colorSpace.d_ptr->iccProfile = iccProfile;
     return colorSpace;
 }
 
@@ -774,7 +758,7 @@ QColorTransform QColorSpace::transformationToColorSpace(const QColorSpace &color
     if (!isValid() || !colorspace.isValid())
         return QColorTransform();
 
-    return d_ptr->transformationToColorSpace(colorspace.d_ptr);
+    return d_ptr->transformationToColorSpace(colorspace.d_ptr.get());
 }
 
 /*!
diff --git a/src/gui/painting/qcolorspace.h b/src/gui/painting/qcolorspace.h
index 07f1ae4c31..d31bf1a326 100644
--- a/src/gui/painting/qcolorspace.h
+++ b/src/gui/painting/qcolorspace.h
@@ -51,6 +51,8 @@ QT_BEGIN_NAMESPACE
 class QColorSpacePrivate;
 class QPointF;
 
+QT_DECLARE_QESDP_SPECIALIZATION_DTOR_WITH_EXPORT(QColorSpacePrivate, Q_GUI_EXPORT)
+
 class Q_GUI_EXPORT QColorSpace
 {
     Q_GADGET
@@ -80,7 +82,7 @@ public:
     };
     Q_ENUM(TransferFunction)
 
-    QColorSpace();
+    QColorSpace() noexcept = default;
     QColorSpace(NamedColorSpace namedColorSpace);
     QColorSpace(Primaries primaries, TransferFunction fun, float gamma = 0.0f);
     QColorSpace(Primaries primaries, float gamma);
@@ -89,12 +91,15 @@ public:
                 TransferFunction fun, float gamma = 0.0f);
     ~QColorSpace();
 
-    QColorSpace(const QColorSpace &colorSpace);
-    QColorSpace &operator=(const QColorSpace &colorSpace);
+    QColorSpace(const QColorSpace &colorSpace) noexcept;
+    QColorSpace &operator=(const QColorSpace &colorSpace) noexcept
+    {
+        QColorSpace copy(colorSpace);
+        swap(copy);
+        return *this;
+    }
 
-    QColorSpace(QColorSpace &&colorSpace) noexcept
-            : d_ptr(qExchange(colorSpace.d_ptr, nullptr))
-    { }
+    QColorSpace(QColorSpace &&colorSpace) noexcept = default;
     QT_MOVE_ASSIGNMENT_OPERATOR_IMPL_VIA_MOVE_AND_SWAP(QColorSpace)
 
     void swap(QColorSpace &colorSpace) noexcept
@@ -111,6 +116,7 @@ public:
     void setPrimaries(const QPointF &whitePoint, const QPointF &redPoint,
                       const QPointF &greenPoint, const QPointF &bluePoint);
 
+    void detach();
     bool isValid() const noexcept;
 
     friend Q_GUI_EXPORT bool operator==(const QColorSpace &colorSpace1, const QColorSpace &colorSpace2);
@@ -125,7 +131,7 @@ public:
 
 private:
     friend class QColorSpacePrivate;
-    QColorSpacePrivate *d_ptr = nullptr;
+    QExplicitlySharedDataPointer<QColorSpacePrivate> d_ptr;
 
 #ifndef QT_NO_DEBUG_STREAM
     friend Q_GUI_EXPORT QDebug operator<<(QDebug dbg, const QColorSpace &colorSpace);
diff --git a/src/gui/painting/qcolorspace_p.h b/src/gui/painting/qcolorspace_p.h
index e7add19ed3..a6c0616e4d 100644
--- a/src/gui/painting/qcolorspace_p.h
+++ b/src/gui/painting/qcolorspace_p.h
@@ -95,24 +95,14 @@ public:
     QColorSpacePrivate(const QColorSpacePrimaries &primaries, QColorSpace::TransferFunction fun, float gamma);
     QColorSpacePrivate(const QColorSpacePrivate &other) = default;
 
-    // named different from get to avoid accidental detachs
-    static QColorSpacePrivate *getWritable(QColorSpace &colorSpace)
+    static const QColorSpacePrivate *get(const QColorSpace &colorSpace)
     {
-        if (!colorSpace.d_ptr) {
-            colorSpace.d_ptr = new QColorSpacePrivate;
-            colorSpace.d_ptr->ref.ref();
-        } else if (colorSpace.d_ptr->ref.loadRelaxed() != 1) {
-            colorSpace.d_ptr->ref.deref();
-            colorSpace.d_ptr = new QColorSpacePrivate(*colorSpace.d_ptr);
-            colorSpace.d_ptr->ref.ref();
-        }
-        Q_ASSERT(colorSpace.d_ptr->ref.loadRelaxed() == 1);
-        return colorSpace.d_ptr;
+        return colorSpace.d_ptr.get();
     }
 
-    static const QColorSpacePrivate *get(const QColorSpace &colorSpace)
+    static QColorSpacePrivate *get(QColorSpace &colorSpace)
     {
-        return colorSpace.d_ptr;
+        return colorSpace.d_ptr.get();
     }
 
     void initialize();
diff --git a/src/gui/painting/qicc.cpp b/src/gui/painting/qicc.cpp
index 746ef43692..5e30ace549 100644
--- a/src/gui/painting/qicc.cpp
+++ b/src/gui/painting/qicc.cpp
@@ -709,7 +709,8 @@ bool fromIccProfile(const QByteArray &data, QColorSpace *colorSpace)
         }
     }
 
-    QColorSpacePrivate *colorspaceDPtr = QColorSpacePrivate::getWritable(*colorSpace);
+    colorSpace->detach();
+    QColorSpacePrivate *colorspaceDPtr = QColorSpacePrivate::get(*colorSpace);
 
     if (header.inputColorSpace == uint(ColorSpaceType::Rgb)) {
         // Parse XYZ tags