Config: Allow passing a DefaultState object to Set functions to delete keys.

2 files changed, 26 insertions, 13 deletions

diff --git a/Source/Core/Common/Config/Config.h b/Source/Core/Common/Config/Config.h
index 1c91bc65af..d7b370282a 100644
--- a/Source/Core/Common/Config/Config.h
+++ b/Source/Core/Common/Config/Config.h
@@ -100,32 +100,32 @@ LayerType GetActiveLayerForConfig(const Info<T>& info)
   return GetActiveLayerForConfig(info.GetLocation());
 }
 
-template <typename T>
-void Set(LayerType layer, const Info<T>& info, const std::common_type_t<T>& value)
+template <typename InfoT, typename ValueT>
+void Set(LayerType layer, const InfoT& info, const ValueT& value)
 {
   if (GetLayer(layer)->Set(info, value))
     OnConfigChanged();
 }
 
-template <typename T>
-void SetBase(const Info<T>& info, const std::common_type_t<T>& value)
+template <typename InfoT, typename ValueT>
+void SetBase(const Info<InfoT>& info, const ValueT& value)
 {
-  Set<T>(LayerType::Base, info, value);
+  Set(LayerType::Base, info, value);
 }
 
-template <typename T>
-void SetCurrent(const Info<T>& info, const std::common_type_t<T>& value)
+template <typename InfoT, typename ValueT>
+void SetCurrent(const Info<InfoT>& info, const ValueT& value)
 {
-  Set<T>(LayerType::CurrentRun, info, value);
+  Set(LayerType::CurrentRun, info, value);
 }
 
-template <typename T>
-void SetBaseOrCurrent(const Info<T>& info, const std::common_type_t<T>& value)
+template <typename InfoT, typename ValueT>
+void SetBaseOrCurrent(const Info<InfoT>& info, const ValueT& value)
 {
   if (GetActiveLayerForConfig(info) == LayerType::Base)
-    Set<T>(LayerType::Base, info, value);
+    Set(LayerType::Base, info, value);
   else
-    Set<T>(LayerType::CurrentRun, info, value);
+    Set(LayerType::CurrentRun, info, value);
 }
 
 template <typename T>
diff --git a/Source/Core/Common/Config/Layer.h b/Source/Core/Common/Config/Layer.h
index 5e3f61c1e6..58859789ca 100644
--- a/Source/Core/Common/Config/Layer.h
+++ b/Source/Core/Common/Config/Layer.h
@@ -8,7 +8,6 @@
 #include <optional>
 #include <string>
 #include <type_traits>
-#include <vector>
 
 #include "Common/Config/ConfigInfo.h"
 #include "Common/Config/Enums.h"
@@ -16,6 +15,12 @@
 
 namespace Config
 {
+// Setting a key to an object of this type will delete the key.
+struct DefaultState
+{
+  friend constexpr bool operator==(DefaultState, DefaultState) { return true; };
+};
+
 namespace detail
 {
 template <typename T, std::enable_if_t<!std::is_enum<T>::value>* = nullptr>
@@ -117,11 +122,19 @@ public:
   }
 
   template <typename T>
+  bool Set(const Info<T>& config_info, DefaultState)
+  {
+    return DeleteKey(config_info.GetLocation());
+  }
+
+  template <typename T>
   bool Set(const Info<T>& config_info, const std::common_type_t<T>& value)
   {
     return Set(config_info.GetLocation(), value);
   }
 
+  bool Set(const Location& location, DefaultState) { return DeleteKey(location); }
+
   template <typename T>
   bool Set(const Location& location, const T& value)
   {