Move out Overloads to util.h

...instead of tucking the template in filesourceinfo.cpp where it surely
will be forgotten.

2 files changed, 14 insertions, 8 deletions

diff --git a/lib/events/filesourceinfo.cpp b/lib/events/filesourceinfo.cpp
index 11f93d80..e8b6794b 100644
--- a/lib/events/filesourceinfo.cpp
+++ b/lib/events/filesourceinfo.cpp
@@ -5,6 +5,7 @@
 #include "filesourceinfo.h"
 
 #include "logging.h"
+#include "util.h"
 
 #ifdef Quotient_E2EE_ENABLED
 #    include "e2ee/qolmutils.h"
@@ -140,14 +141,6 @@ void JsonObjectConverter<JWK>::fillFrom(const QJsonObject& jo, JWK& pod)
     fromJson(jo.value("ext"_ls), pod.ext);
 }
 
-template <typename... FunctorTs>
-struct Overloads : FunctorTs... {
-    using FunctorTs::operator()...;
-};
-
-template <typename... FunctorTs>
-Overloads(FunctorTs&&...) -> Overloads<FunctorTs...>;
-
 QUrl Quotient::getUrlFromSourceInfo(const FileSourceInfo& fsi)
 {
     return std::visit(Overloads { [](const QUrl& url) { return url; },
diff --git a/lib/util.h b/lib/util.h
index d1623881..8a30f457 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -170,6 +170,19 @@ constexpr ImplPtr<ImplType> ZeroImpl()
     return { nullptr, [](ImplType*) { /* nullptr doesn't need deletion */ } };
 }
 
+//! \brief Multiplex several functors in one
+//!
+//! This is a well-known trick to wrap several lambdas into a single functor
+//! class that can be passed to std::visit.
+//! \sa  https://en.cppreference.com/w/cpp/utility/variant/visit
+template <typename... FunctorTs>
+struct Overloads : FunctorTs... {
+    using FunctorTs::operator()...;
+};
+
+template <typename... FunctorTs>
+Overloads(FunctorTs&&...) -> Overloads<FunctorTs...>;
+
 /** Convert what looks like a URL or a Matrix ID to an HTML hyperlink */
 QUOTIENT_API void linkifyUrls(QString& htmlEscapedText);