QtSupport: Split QtVersionFactory::create()

... into a 'canCreate()' and the actual creation, which can be
done by the already registered m_creator.

Simpler interface, with the (temporary) regression that the
EmbeddedLinuxQtVersion get constructed twice, once only to
determine that it should be alive afterwards. Will be fixed later.

Change-Id: I5da2cafe473b25a0207bbd628632c9a259780361
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

4 files changed, 19 insertions, 11 deletions

diff --git a/src/plugins/qtsupport/desktopqtversionfactory.cpp b/src/plugins/qtsupport/desktopqtversionfactory.cpp
index 368fef9026..b7a8bcea90 100644
--- a/src/plugins/qtsupport/desktopqtversionfactory.cpp
+++ b/src/plugins/qtsupport/desktopqtversionfactory.cpp
@@ -35,11 +35,5 @@ DesktopQtVersionFactory::DesktopQtVersionFactory()
     setQtVersionCreator([] { return new DesktopQtVersion; });
     setSupportedType(Constants::DESKTOPQT);
     setPriority(0); // Lowest of all, we want to be the fallback
-}
-
-BaseQtVersion *DesktopQtVersionFactory::create(ProFileEvaluator *evaluator)
-{
-    Q_UNUSED(evaluator);
-    // we are the fallback :) so we don't care what kind of qt it is
-    return new DesktopQtVersion;
+    // No further restrictions. We are the fallback :) so we don't care what kind of qt it is.
 }
diff --git a/src/plugins/qtsupport/desktopqtversionfactory.h b/src/plugins/qtsupport/desktopqtversionfactory.h
index d2d12e2f95..00d308456e 100644
--- a/src/plugins/qtsupport/desktopqtversionfactory.h
+++ b/src/plugins/qtsupport/desktopqtversionfactory.h
@@ -34,8 +34,6 @@ class DesktopQtVersionFactory : public QtVersionFactory
 {
 public:
     DesktopQtVersionFactory();
-
-    BaseQtVersion *create(ProFileEvaluator *evaluator) override;
 };
 
 } // Internal
diff --git a/src/plugins/qtsupport/qtversionfactory.cpp b/src/plugins/qtsupport/qtversionfactory.cpp
index 4a00a199be..99c5e62478 100644
--- a/src/plugins/qtsupport/qtversionfactory.cpp
+++ b/src/plugins/qtsupport/qtversionfactory.cpp
@@ -71,6 +71,18 @@ BaseQtVersion *QtVersionFactory::restore(const QString &type, const QVariantMap
     return version;
 }
 
+BaseQtVersion *QtVersionFactory::create() const
+{
+    QTC_ASSERT(m_creator, return nullptr);
+    return m_creator();
+}
+
+bool QtVersionFactory::canCreate(ProFileEvaluator *evaluator) const
+{
+    Q_UNUSED(evaluator);
+    return true;
+}
+
 BaseQtVersion *QtVersionFactory::createQtVersionFromQMakePath(const Utils::FileName &qmakePath, bool isAutoDetected, const QString &autoDetectionSource, QString *error)
 {
     QHash<ProKey, ProString> versionInfo;
@@ -98,7 +110,9 @@ BaseQtVersion *QtVersionFactory::createQtVersionFromQMakePath(const Utils::FileN
         return nullptr;
 
     foreach (QtVersionFactory *factory, factories) {
-        if (BaseQtVersion *ver = factory->create(&evaluator)) {
+        if (factory->canCreate(&evaluator)) {
+            BaseQtVersion *ver = factory->create();
+            QTC_ASSERT(ver, continue);
             ver->setupQmakePathAndId(qmakePath);
             ver->setAutoDetectionSource(autoDetectionSource);
             ver->setIsAutodetected(isAutoDetected);
diff --git a/src/plugins/qtsupport/qtversionfactory.h b/src/plugins/qtsupport/qtversionfactory.h
index c66a87a740..59c8545157 100644
--- a/src/plugins/qtsupport/qtversionfactory.h
+++ b/src/plugins/qtsupport/qtversionfactory.h
@@ -54,7 +54,9 @@ public:
     /// a qtversion, the priority of the desktop factory is 0 and
     /// the desktop factory claims to handle all paths
     int priority() const { return m_priority; }
-    virtual BaseQtVersion *create(ProFileEvaluator *evaluator) = 0;
+
+    BaseQtVersion *create() const;
+    virtual bool canCreate(ProFileEvaluator *evaluator) const;
 
     static BaseQtVersion *createQtVersionFromQMakePath(
             const Utils::FileName &qmakePath, bool isAutoDetected = false,