Pass non-trivial/large function args by reference

Fixes a bunch of `-Wclazy-function-args-by-ref` warnings. See
https://github.com/KDE/clazy/blob/master/docs/checks/README-function-args-by-ref.md
for details.

Most of these changes are automated, using the clazy fixit by setting
the `CLAZY_EXPORT_FIXES` before compilation and then running:

    $ mkdir /tmp/patch
    $ find ../src -iname "*.yaml" -exec mv {} /tmp/patch \;
    $ clang-apply-replacements /tmp/patch

2 files changed, 3 insertions, 3 deletions

diff --git a/src/recording/recordingmanager.cpp b/src/recording/recordingmanager.cpp
index 54d635de11..63dab0851a 100644
--- a/src/recording/recordingmanager.cpp
+++ b/src/recording/recordingmanager.cpp
@@ -74,7 +74,7 @@ RecordingManager::~RecordingManager() {
     delete m_pToggleRecording;
 }
 
-QString RecordingManager::formatDateTimeForFilename(QDateTime dateTime) const {
+QString RecordingManager::formatDateTimeForFilename(const QDateTime& dateTime) const {
     // Use a format based on ISO 8601. Windows does not support colons in
     // filenames so we can't use them anywhere.
     QString formatted = dateTime.toString("yyyy-MM-dd_hh'h'mm'm'ss's'");
diff --git a/src/recording/recordingmanager.h b/src/recording/recordingmanager.h
index f458c14cd1..526963f6cb 100644
--- a/src/recording/recordingmanager.h
+++ b/src/recording/recordingmanager.h
@@ -48,7 +48,7 @@ class RecordingManager : public QObject
     // Emits the cumulative number of bytes currently recorded.
     void bytesRecorded(int);
     void isRecording(bool);
-    void durationRecorded(QString);
+    void durationRecorded(const QString&);
 
   public slots:
     void slotIsRecording(bool recording, bool error);
@@ -58,7 +58,7 @@ class RecordingManager : public QObject
     void slotToggleRecording(double value);
 
   private:
-    QString formatDateTimeForFilename(QDateTime dateTime) const;
+    QString formatDateTimeForFilename(const QDateTime& dateTime) const;
     // slotBytesRecorded just noticed that recording must be interrupted
     // to split the file. The nth filename will follow the date/time
     // name of the first split but with a suffix.