X-Git-Url: https://git.quassel-irc.org/?p=quassel.git;a=blobdiff_plain;f=src%2Fcommon%2Ffunchelpers.h;h=fcd5aa477ab4c7de5a2d588e127891430a6ba3f5;hp=01ee8222807796e3f426afa4c031402aa7098ea1;hb=0859ff9b7f8633925dde6482d57774f229a937a6;hpb=c1cf157116de7fc3da96203aa6f03c38c7ebb650

diff --git a/src/common/funchelpers.h b/src/common/funchelpers.h
index 01ee8222..fcd5aa47 100644
--- a/src/common/funchelpers.h
+++ b/src/common/funchelpers.h
@@ -20,8 +20,16 @@
 
 #pragma once
 
+#include <array>
 #include <functional>
 #include <tuple>
+#include <type_traits>
+#include <utility>
+
+#include <QDebug>
+#include <QVariantList>
+
+// ---- Function traits --------------------------------------------------------------------------------------------------------------------
 
 namespace detail {
 
@@ -32,21 +40,27 @@ template<typename Func>
 struct FuncHelper : public FuncHelper<decltype(&Func::operator())>
 {};
 
-// Overload for member function with const call operator
-template<typename C, typename R, typename... Args>
-struct FuncHelper<R (C::*)(Args...) const> : public FuncHelper<R (C::*)(Args...)>
-{};
+// Overload for free function
+template<typename R, typename... Args>
+struct FuncHelper<R(*)(Args...)>
+{
+    using FunctionType = std::function<R(Args...)>;
+    using ReturnType = R;
+    using ArgsTuple = std::tuple<Args...>;
+};
 
 // Overload for member function with non-const call operator
 template<typename C, typename R, typename... Args>
-struct FuncHelper<R (C::*)(Args...)>
+struct FuncHelper<R(C::*)(Args...)> : public FuncHelper<R(*)(Args...)>
 {
     using ClassType = C;
-    using FunctionType = std::function<R(Args...)>;
-    using ReturnType = R;
-    using ArgsTuple = std::tuple<Args...>;
 };
 
+// Overload for member function with const call operator
+template<typename C, typename R, typename... Args>
+struct FuncHelper<R(C::*)(Args...) const> : public FuncHelper<R(C::*)(Args...)>
+{};
+
 /// @endcond
 
 }  // namespace detail
@@ -55,4 +69,52 @@ struct FuncHelper<R (C::*)(Args...)>
  * Provides traits for the given callable.
  */
 template<typename Callable>
-using MemberFunction = detail::FuncHelper<Callable>;
+using FunctionTraits = detail::FuncHelper<Callable>;
+
+// ---- Invoke function with argument list -------------------------------------------------------------------------------------------------
+
+namespace detail {
+
+// Helper for unpacking the argument list via an index sequence
+template<typename Callable, std::size_t ...Is, typename ArgsTuple = typename FunctionTraits<Callable>::ArgsTuple>
+bool invokeWithArgsList(const Callable& c, const QVariantList& args, std::index_sequence<Is...>)
+{
+    // Sanity check that all types can be converted
+    std::array<bool, std::tuple_size<ArgsTuple>::value> convertible{{args[Is].canConvert<std::decay_t<std::tuple_element_t<Is, ArgsTuple>>>()...}};
+    for (size_t i = 0; i < convertible.size(); ++i) {
+        if (!convertible[i]) {
+            qWarning() << "Cannot convert parameter" << i << "from type" << args[static_cast<int>(i)].typeName() << "to expected argument type";
+            return false;
+        }
+    }
+
+    // Invoke callable
+    c(args[Is].value<std::decay_t<std::tuple_element_t<Is, ArgsTuple>>>()...);
+    return true;
+}
+
+}  // detail
+
+/**
+ * Invokes the given callable with the arguments contained in the given variant list.
+ *
+ * The types contained in the given QVariantList are converted to the types expected by the callable.
+ * If the conversion fails, or if the argument count does not match, this function returns false and
+ * the callable is not invoked.
+ *
+ * @param c    Callable
+ * @param args Arguments to be given to the callable
+ * @returns true if the callable could be invoked with the given list of arguments
+ */
+template<typename Callable>
+bool invokeWithArgsList(const Callable& c, const QVariantList& args)
+{
+    using ArgsTuple = typename FunctionTraits<Callable>::ArgsTuple;
+    constexpr auto tupleSize = std::tuple_size<ArgsTuple>::value;
+
+    if (tupleSize != args.size()) {
+        qWarning().nospace() << "Argument count mismatch! Expected: " << tupleSize << ", actual: " << args.size();
+        return false;
+    }
+    return detail::invokeWithArgsList(c, args, std::make_index_sequence<tupleSize>{});
+}