Cleanup reference counting in internal::Base class (qtconcurrent)

It is better to use QSharedData and QExplicitlySharedDataPointer then
doing manual ref counting.

Change-Id: I5674046141701bd48a53415ab96fcb6b538e79e6
Reviewed-on: http://codereview.qt.nokia.com/1440
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Olivier Goffart <olivier.goffart@nokia.com>

2 files changed, 7 insertions, 18 deletions

diff --git a/src/corelib/concurrent/qtconcurrentexception.cpp b/src/corelib/concurrent/qtconcurrentexception.cpp
index 933ad3c264..237152c0d3 100644
--- a/src/corelib/concurrent/qtconcurrentexception.cpp
+++ b/src/corelib/concurrent/qtconcurrentexception.cpp
@@ -40,6 +40,7 @@
 ****************************************************************************/
 
 #include "qtconcurrentexception.h"
+#include "QtCore/qshareddata.h"
 
 #ifndef QT_NO_QFUTURE
 #ifndef QT_NO_EXCEPTIONS
@@ -141,15 +142,14 @@ Exception *UnhandledException::clone() const
 
 namespace internal {
 
-class Base
+class Base : public QSharedData
 {
 public:
     Base(Exception *exception)
-    : exception(exception), refCount(1), hasThrown(false) { }
+    : exception(exception), hasThrown(false) { }
     ~Base() { delete exception; }
 
     Exception *exception;
-    QAtomicInt refCount;
     bool hasThrown;
 };
 
@@ -158,27 +158,15 @@ ExceptionHolder::ExceptionHolder(Exception *exception)
 
 ExceptionHolder::ExceptionHolder(const ExceptionHolder &other)
 : base(other.base)
-{
-    base->refCount.ref();
-}
+{}
 
 void ExceptionHolder::operator=(const ExceptionHolder &other)
 {
-    if (base == other.base)
-        return;
-
-    if (base->refCount.deref() == false)
-        delete base;
-
     base = other.base;
-    base->refCount.ref();
 }
 
 ExceptionHolder::~ExceptionHolder()
-{
-    if (base->refCount.deref() == 0)
-        delete base;
-}
+{}
 
 Exception *ExceptionHolder::exception() const
 {
diff --git a/src/corelib/concurrent/qtconcurrentexception.h b/src/corelib/concurrent/qtconcurrentexception.h
index b58b3ba23a..1c100a5206 100644
--- a/src/corelib/concurrent/qtconcurrentexception.h
+++ b/src/corelib/concurrent/qtconcurrentexception.h
@@ -47,6 +47,7 @@
 #ifndef QT_NO_QFUTURE
 
 #include <QtCore/qatomic.h>
+#include <QtCore/qshareddata.h>
 
 #ifndef QT_NO_EXCEPTIONS
 #  include <exception>
@@ -87,7 +88,7 @@ public:
     void operator=(const ExceptionHolder &other);
     ~ExceptionHolder();
     Exception *exception() const;
-    Base *base;
+    QExplicitlySharedDataPointer<Base> base;
 };
 
 class Q_CORE_EXPORT ExceptionStore