ProjectExplorer: Simplify DeployConfigFactory::availableBuildTargets

It only ever returned either an empty list, or a list with a single
empty string. Using a bool return value to distiguish the cases is
less convoluted.

This is a leftover from the time when a DeployConfigurationFactory
could potentially create more than on DeployConfiguration, but this
is not supported anymore, as factories are cheap nowadays.

Change-Id: I4f2a91d3509d2b978949211ee709863d5ff460c7
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/android/androiddeployconfiguration.cpp

@@ -60,20 +60,18 @@ AndroidDeployConfigurationFactory::AndroidDeployConfigurationFactory()
     setDefaultDisplayName(AndroidDeployConfiguration::tr("Deploy to Android device"));
 }
 
-QList<QString> AndroidDeployConfigurationFactory::availableBuildTargets(Target *parent) const
+bool AndroidDeployConfigurationFactory::hasAvailableBuildTargets(Target *parent) const
 {
     if (!parent->project()->id().name().startsWith("QmlProjectManager.QmlProject")) {
         // Avoid tool chain check for QML Project
         Core::Id cxxLangId(ProjectExplorer::Constants::CXX_LANGUAGE_ID);
         ToolChain *tc = ToolChainKitInformation::toolChain(parent->kit(), cxxLangId);
         if (!tc || tc->targetAbi().osFlavor() != Abi::AndroidLinuxFlavor)
-            return {};
+            return false;
     }
 
     QtSupport::BaseQtVersion *qt = QtSupport::QtKitInformation::qtVersion(parent->kit());
-    if (!qt || qt->type() != Constants::ANDROIDQT)
-        return {};
-    return {QString()};
+    return qt && qt->type() == Constants::ANDROIDQT;
 }
 
 } // namespace Internal

src/plugins/android/androiddeployconfiguration.h

@@ -44,7 +44,7 @@ class AndroidDeployConfigurationFactory : public ProjectExplorer::DeployConfigur
 public:
     AndroidDeployConfigurationFactory();
 
-    QList<QString> availableBuildTargets(ProjectExplorer::Target *parent) const override;
+    bool hasAvailableBuildTargets(ProjectExplorer::Target *parent) const override;
 };
 
 } // namespace Internal

src/plugins/projectexplorer/deployconfiguration.cpp

@@ -153,16 +153,14 @@ DeployConfigurationFactory::~DeployConfigurationFactory()
 
 QList<Core::Id> DeployConfigurationFactory::availableCreationIds(Target *parent) const
 {
-    if (!canHandle(parent))
+    if (canHandle(parent) && hasAvailableBuildTargets(parent))
+        return {m_deployConfigBaseId};
     return {};
-    return Utils::transform(availableBuildTargets(parent), [this](const QString &suffix) {
-        return m_deployConfigBaseId.withSuffix(suffix);
-    });
 }
 
-QList<QString> DeployConfigurationFactory::availableBuildTargets(Target *) const
+bool DeployConfigurationFactory::hasAvailableBuildTargets(Target *) const
 {
-    return {QString()};
+    return true;
 }
 
 QString DeployConfigurationFactory::displayNameForBuildTarget(const QString &) const

src/plugins/projectexplorer/deployconfiguration.h

@@ -98,7 +98,7 @@ public:
 
 protected:
     virtual bool canHandle(ProjectExplorer::Target *target) const;
-    virtual QList<QString> availableBuildTargets(Target *parent) const;
+    virtual bool hasAvailableBuildTargets(Target *parent) const;
     virtual QString displayNameForBuildTarget(const QString &buildTarget) const;
 
     using DeployConfigurationCreator = std::function<DeployConfiguration *(Target *)>;