From 54232d6ea98a313390ee8f36bbadadce49ff97f3 Mon Sep 17 00:00:00 2001
From: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Date: Tue, 29 Sep 2020 18:11:23 +0200
Subject: [PATCH] Streamline the template specialization of QESDP's dtor

Declaring and implementing out of line a specialization for
QESDP's destructor is needed if we have an implicitly shared
type and we want to provide an inline move constructor for it.

The code is however a bit heavy on the eyes, and the full
implementation for the destructor must be provided (read:
copy and pasted) -- the specialization destructor cannot
just "reuse" the one from the primary template.

This patch adds a few macros to streamline the above, so
that we can start using the same pattern in more places.
These macros are completely private for the moment being;
we don't want to push this solution for our users.

Port QPixmap to the new macros.

Change-Id: Ia6a51ad988483e44c9d97c0eca2fb003b6bd21e3
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
---
 bin/syncqt.pl                   |  1 +
 src/corelib/tools/qshareddata.h | 26 ++++++++++++++++++++++++++
 src/gui/image/qpixmap.cpp       |  5 ++---
 src/gui/image/qpixmap.h         |  2 +-
 4 files changed, 30 insertions(+), 4 deletions(-)

diff --git a/bin/syncqt.pl b/bin/syncqt.pl
index 3c8ccf9374d..c22cbfa8d09 100755
--- a/bin/syncqt.pl
+++ b/bin/syncqt.pl
@@ -233,6 +233,7 @@ sub classNames {
                 $line .= ";" if($line =~ m/^QT_(BEGIN|END)_NAMESPACE(_[A-Z]+)*[\r\n]*$/); #qt macro
                 $line .= ";" if($line =~ m/^QT_MODULE\(.*\)[\r\n]*$/); # QT_MODULE macro
                 $line .= ";" if($line =~ m/^QT_WARNING_(PUSH|POP|DISABLE_\w+\(.*\))[\r\n]*$/); # qt macros
+                $line .= ";" if($line =~ m/^QT_DECLARE_QE?SDP_SPECIALIZATION_DTOR(_WITH_EXPORT)?\(.*\)[\r\n]*$/); # qt macros
                 $$requires = $1 if ($line =~ m/^QT_REQUIRE_CONFIG\((.*)\);[\r\n]*$/);
                 $parsable .= " " . $line;
             }
diff --git a/src/corelib/tools/qshareddata.h b/src/corelib/tools/qshareddata.h
index 71f2e177992..ffd4d4cf0bf 100644
--- a/src/corelib/tools/qshareddata.h
+++ b/src/corelib/tools/qshareddata.h
@@ -304,6 +304,32 @@ Q_INLINE_TEMPLATE size_t qHash(const QExplicitlySharedDataPointer<T> &ptr, size_
 template<typename T> Q_DECLARE_TYPEINFO_BODY(QSharedDataPointer<T>, Q_MOVABLE_TYPE);
 template<typename T> Q_DECLARE_TYPEINFO_BODY(QExplicitlySharedDataPointer<T>, Q_MOVABLE_TYPE);
 
+#define QT_DECLARE_QSDP_SPECIALIZATION_DTOR(Class) \
+    template<> QSharedDataPointer<Class>::~QSharedDataPointer();
+
+#define QT_DECLARE_QSDP_SPECIALIZATION_DTOR_WITH_EXPORT(Class, ExportMacro) \
+    template<> ExportMacro QSharedDataPointer<Class>::~QSharedDataPointer();
+
+#define QT_DEFINE_QSDP_SPECIALIZATION_DTOR(Class) \
+    template<> QSharedDataPointer<Class>::~QSharedDataPointer() \
+    { \
+        if (d && !d->ref.deref()) \
+            delete d; \
+    }
+
+#define QT_DECLARE_QESDP_SPECIALIZATION_DTOR(Class) \
+    template<> QExplicitlySharedDataPointer<Class>::~QExplicitlySharedDataPointer();
+
+#define QT_DECLARE_QESDP_SPECIALIZATION_DTOR_WITH_EXPORT(Class, ExportMacro) \
+    template<> ExportMacro QExplicitlySharedDataPointer<Class>::~QExplicitlySharedDataPointer();
+
+#define QT_DEFINE_QESDP_SPECIALIZATION_DTOR(Class) \
+    template<> QExplicitlySharedDataPointer<Class>::~QExplicitlySharedDataPointer() \
+    { \
+        if (d && !d->ref.deref()) \
+            delete d; \
+    }
+
 QT_END_NAMESPACE
 
 #endif // QSHAREDDATA_H
diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index c3ae8537956..d8473001aad 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -229,9 +229,8 @@ QPixmap::QPixmap(const QPixmap &pixmap)
 
     \sa swap() operator=(QPixmap&&)
 */
-template<>
-QExplicitlySharedDataPointer<QPlatformPixmap>::~QExplicitlySharedDataPointer()
-{ if (d && !d->ref.deref()) delete d; }
+
+QT_DEFINE_QESDP_SPECIALIZATION_DTOR(QPlatformPixmap)
 
 /*!
     Constructs a pixmap from the given \a xpm data, which must be a
diff --git a/src/gui/image/qpixmap.h b/src/gui/image/qpixmap.h
index e7315976594..42d4e271026 100644
--- a/src/gui/image/qpixmap.h
+++ b/src/gui/image/qpixmap.h
@@ -57,7 +57,7 @@ class QImageReader;
 class QColor;
 class QVariant;
 class QPlatformPixmap;
-template<> Q_GUI_EXPORT QExplicitlySharedDataPointer<QPlatformPixmap>::~QExplicitlySharedDataPointer();
+QT_DECLARE_QESDP_SPECIALIZATION_DTOR_WITH_EXPORT(QPlatformPixmap, Q_GUI_EXPORT)
 
 class Q_GUI_EXPORT QPixmap : public QPaintDevice
 {