1 files changed, 39 insertions, 5 deletions
diff --git a/options/value.hpp b/options/value.hpp
index 92e2878f..9a7487b8 100644
--- a/options/value.hpp
+++ b/options/value.hpp
@@ -14,7 +14,6 @@
 #include "slider.hpp"
 #include "base-value.hpp"
 #include "value-traits.hpp"
-#include "compat/macros.hpp"
 
 #include <type_traits>
 #include <utility>
@@ -38,8 +37,10 @@ namespace options {
 template<typename t>
 class value final : public value_
 {
-    static_assert(std::is_same_v<t, remove_cvref_t<t>>);
+    static_assert(std::is_same_v<t, std::remove_cvref_t<t>>);
+    mutable QMutex mtx;
     const t def;
+    mutable t cached_value;
     using traits = detail::value_traits<t>;
 
     never_inline
@@ -92,10 +93,42 @@ public:
         return traits::qvariant_from_value(def);
     }
 
+    never_inline
+    void notify_() const override
+    {
+        auto x = get();
+        {
+            QMutexLocker l(&mtx);
+            cached_value = x;
+        }
+        maybe_trace("notify +");
+        emit valueChanged(traits::storage_from_value(x));
+        maybe_trace("notify -");
+    }
+
+    never_inline
     void notify() const override
     {
-        if (!is_null())
-            emit valueChanged(traits::storage_from_value(get()));
+        if (is_null())
+            return;
+
+        auto x = get();
+        {
+            QMutexLocker l(&mtx);
+            if (traits::is_equal(x, cached_value))
+            {
+                //maybe_trace("notify ~");
+                return;
+            }
+            else
+            {
+                cached_value = x;
+                l.unlock();
+                maybe_trace("notify +");
+                emit valueChanged(traits::storage_from_value(x));
+                maybe_trace("notify -");
+            }
+        }
     }
 
     auto& operator=(t&& datum) noexcept
@@ -104,6 +137,7 @@ public:
             return *this;
 
         store_variant(traits::qvariant_from_value(traits::pass_value(datum)));
+        maybe_trace("set-value");
         return *this;
     }
 
@@ -126,7 +160,7 @@ public:
     static constexpr Qt::ConnectionType DIRECT_CONNTYPE = Qt::DirectConnection;
     static constexpr Qt::ConnectionType SAFE_CONNTYPE = Qt::QueuedConnection;
 
-    value(bundle b, const QString& name, t def) noexcept : value_(b, name), def(std::move(def))
+    value(bundle b, const QString& name, t def) noexcept : value_(b, name), def(std::move(def)), cached_value{get()}
     {
     }