4 files changed, 7 insertions, 7 deletions
diff --git a/src/engine/cachingreader/cachingreader.cpp b/src/engine/cachingreader/cachingreader.cpp
index d7332eb27c..592371a686 100644
--- a/src/engine/cachingreader/cachingreader.cpp
+++ b/src/engine/cachingreader/cachingreader.cpp
@@ -40,7 +40,7 @@ const SINT kNumberOfCachedChunksInMemory = 80;
 
 } // anonymous namespace
 
-CachingReader::CachingReader(QString group,
+CachingReader::CachingReader(const QString& group,
         UserSettingsPointer config)
         : m_pConfig(config),
           // Limit the number of in-flight requests to the worker. This should
diff --git a/src/engine/cachingreader/cachingreader.h b/src/engine/cachingreader/cachingreader.h
index b46f817877..c5f5a6ee32 100644
--- a/src/engine/cachingreader/cachingreader.h
+++ b/src/engine/cachingreader/cachingreader.h
@@ -72,8 +72,8 @@ class CachingReader : public QObject {
 
   public:
     // Construct a CachingReader with the given group.
-    CachingReader(QString group,
-                  UserSettingsPointer _config);
+    CachingReader(const QString& group,
+            UserSettingsPointer _config);
     ~CachingReader() override;
 
     void process();
@@ -112,7 +112,7 @@ class CachingReader : public QObject {
     // Emitted once a new track is loaded and ready to be read from.
     void trackLoading();
     void trackLoaded(TrackPointer pTrack, int iSampleRate, int iNumSamples);
-    void trackLoadFailed(TrackPointer pTrack, QString reason);
+    void trackLoadFailed(TrackPointer pTrack, const QString& reason);
 
   private:
     const UserSettingsPointer m_pConfig;
diff --git a/src/engine/cachingreader/cachingreaderworker.cpp b/src/engine/cachingreader/cachingreaderworker.cpp
index ae5b9d8256..aefd482d04 100644
--- a/src/engine/cachingreader/cachingreaderworker.cpp
+++ b/src/engine/cachingreader/cachingreaderworker.cpp
@@ -18,7 +18,7 @@ mixxx::Logger kLogger("CachingReaderWorker");
 } // anonymous namespace
 
 CachingReaderWorker::CachingReaderWorker(
-        QString group,
+        const QString& group,
         FIFO<CachingReaderChunkReadRequest>* pChunkReadRequestFIFO,
         FIFO<ReaderStatusUpdate>* pReaderStatusFIFO)
         : m_group(group),
diff --git a/src/engine/cachingreader/cachingreaderworker.h b/src/engine/cachingreader/cachingreaderworker.h
index 78b36dd396..09801eebb8 100644
--- a/src/engine/cachingreader/cachingreaderworker.h
+++ b/src/engine/cachingreader/cachingreaderworker.h
@@ -96,7 +96,7 @@ class CachingReaderWorker : public EngineWorker {
 
   public:
     // Construct a CachingReader with the given group.
-    CachingReaderWorker(QString group,
+    CachingReaderWorker(const QString& group,
             FIFO<CachingReaderChunkReadRequest>* pChunkReadRequestFIFO,
             FIFO<ReaderStatusUpdate>* pReaderStatusFIFO);
     ~CachingReaderWorker() override = default;
@@ -114,7 +114,7 @@ class CachingReaderWorker : public EngineWorker {
     // Emitted once a new track is loaded and ready to be read from.
     void trackLoading();
     void trackLoaded(TrackPointer pTrack, int iSampleRate, int iNumSamples);
-    void trackLoadFailed(TrackPointer pTrack, QString reason);
+    void trackLoadFailed(TrackPointer pTrack, const QString& reason);
 
   private:
     const QString m_group;