remove const correctness violations

This is possibly related to a livelock where several threads do const
removal in their respective code paths.

Use the `mutable' specifier for the mutexes and spline's cached data.

Now using the `mutable' specifier, get rid of <optional> in
compat/mutex.

2 files changed, 6 insertions, 21 deletions

diff --git a/options/bundle.cpp b/options/bundle.cpp
index 8db4f906..938639b3 100644
--- a/options/bundle.cpp
+++ b/options/bundle.cpp
@@ -20,15 +20,7 @@ using namespace options::globals;
 
 namespace options::detail {
 
-mutex::mutex(QMutex::RecursionMode mode) : QMutex(mode) {}
-
-mutex::operator QMutex*() const
-{
-    return const_cast<QMutex*>(static_cast<const QMutex*>(this));
-}
-
 bundle::bundle(const QString& group_name) :
-      mtx(QMutex::Recursive),
       group_name(group_name),
       saved(group_name),
       transient(saved)
@@ -82,13 +74,13 @@ void bundle::store_kv(const QString& name, const QVariant& new_value)
 
 QVariant bundle::get_variant(const QString& name) const
 {
-    QMutexLocker l(mtx);
+    QMutexLocker l(&mtx);
     return transient.get_variant(name);
 }
 
 bool bundle::contains(const QString &name) const
 {
-    QMutexLocker l(mtx);
+    QMutexLocker l(&mtx);
     return transient.contains(name);
 }
 
diff --git a/options/bundle.hpp b/options/bundle.hpp
index 9ab7f74c..4c2b9781 100644
--- a/options/bundle.hpp
+++ b/options/bundle.hpp
@@ -29,13 +29,6 @@
 #include "export.hpp"
 
 namespace options::detail {
-    class OTR_OPTIONS_EXPORT mutex final : public QMutex
-    {
-    public:
-        explicit mutex(QMutex::RecursionMode mode);
-        cc_noinline operator QMutex*() const; // NOLINT
-    };
-
     class bundle;
 } // ns options::detail
 
@@ -51,7 +44,7 @@ class OTR_OPTIONS_EXPORT bundle final : public QObject, public connector
 {
     Q_OBJECT
 
-    mutex mtx;
+    mutable QMutex mtx { QMutex::Recursive };
     const QString group_name;
     group saved;
     group transient;
@@ -65,7 +58,7 @@ public:
     bundle(const bundle&) = delete;
     bundle& operator=(const bundle&) = delete;
 
-    QMutex* get_mtx() const override { return mtx; }
+    QMutex* get_mtx() const override { return &mtx; }
     QString name() const { return group_name; }
 
     explicit bundle(const QString& group_name);
@@ -100,8 +93,8 @@ private:
     friend OTR_OPTIONS_EXPORT
     std::shared_ptr<v> options::make_bundle(const QString& name);
 
-    [[nodiscard]] std::shared_ptr<v> make_bundle_(const k& key);
-    [[nodiscard]] static bundler& bundler_singleton();
+    std::shared_ptr<v> make_bundle_(const k& key);
+    static bundler& bundler_singleton();
 
     bundler();
     ~bundler();