ProjectExplorer: Simplify Kit settings file access

Check for existence of file in one place instead of once per file
we access.

Change-Id: Ie574d5e1e3e3aac97e239b57e94a58d9d3e7d626
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/projectexplorer/kitmanager.cpp

@@ -126,9 +126,8 @@ void KitManager::restoreKits()
     QList<Kit *> kitsToCheck;
 
     // read all kits from SDK
-    QFileInfo kitFile(ICore::installerResourcePath() + KIT_FILENAME);
-    if (kitFile.exists()) {
-        KitList system = restoreKits(FileName(kitFile));
+    KitList system
+            = restoreKits(FileName::fromString(ICore::installerResourcePath() + KIT_FILENAME));
     // make sure we mark these as autodetected and run additional setup logic
     foreach (Kit *k, system.kits) {
         k->setAutoDetected(true);
@@ -139,13 +138,9 @@ void KitManager::restoreKits()
     // SDK kits are always considered to be up for validation since they might have been
     // extended with additional information by creator in the meantime:
     kitsToValidate = system.kits;
-    }
 
     // read all kits from user file
-    KitList userKits;
-    FileName userSettingsFile(settingsFileName());
-    if (userSettingsFile.exists())
-        userKits = restoreKits(userSettingsFile);
+    KitList userKits = restoreKits(settingsFileName());
     foreach (Kit *k, userKits.kits) {
         if (k->isSdkProvided())
             kitsToCheck.append(k);
@@ -316,6 +311,9 @@ KitManager::KitList KitManager::restoreKits(const FileName &fileName)
 {
     KitList result;
 
+    if (!fileName.exists())
+        return result;
+
     PersistentSettingsReader reader;
     if (!reader.load(fileName)) {
         qWarning("Warning: Failed to read \"%s\", cannot restore kits!",