[PATCH v1] libcamera: base: bound_method: Forward arguments when possible

[Barnabás Pőcze]

Use `std::{forward,move}` to forward the arguments, this enables the
use of move constructors, likely leading to less code and better runtime.
For example, move constructing a libstdc++ `std::shared_ptr` is noticeably
less code than copy constructing one.

Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
---
 include/libcamera/base/bound_method.h | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/include/libcamera/base/bound_method.h b/include/libcamera/base/bound_method.h
index dd3488eeb..47e0a2475 100644
--- a/include/libcamera/base/bound_method.h
+++ b/include/libcamera/base/bound_method.h
@@ -33,8 +33,9 @@ template<typename R, typename... Args>
 class BoundMethodPack : public BoundMethodPackBase
 {
 public:
-	BoundMethodPack(const Args &... args)
-		: args_(args...)
+	template<typename... Ts>
+	BoundMethodPack(Ts &&...args)
+		: args_(std::forward<Ts>(args)...)
 	{
 	}
 
@@ -51,8 +52,9 @@ template<typename... Args>
 class BoundMethodPack<void, Args...> : public BoundMethodPackBase
 {
 public:
-	BoundMethodPack(const Args &... args)
-		: args_(args...)
+	template<typename... Ts>
+	BoundMethodPack(Ts &&...args)
+		: args_(std::forward<Ts>(args)...)
 	{
 	}
 
@@ -136,23 +138,23 @@ public:
 
 	BoundMethodFunctor(T *obj, Object *object, Func func,
 			   ConnectionType type = ConnectionTypeAuto)
-		: BoundMethodArgs<R, Args...>(obj, object, type), func_(func)
+		: BoundMethodArgs<R, Args...>(obj, object, type), func_(std::move(func))
 	{
 	}
 
 	R activate(Args... args, bool deleteMethod = false) override
 	{
 		if (!this->object_)
-			return func_(args...);
+			return func_(std::forward<Args>(args)...);
 
-		auto pack = std::make_shared<PackType>(args...);
+		auto pack = std::make_shared<PackType>(std::forward<Args>(args)...);
 		bool sync = BoundMethodBase::activatePack(pack, deleteMethod);
 		return sync ? pack->returnValue() : R();
 	}
 
 	R invoke(Args... args) override
 	{
-		return func_(args...);
+		return func_(std::forward<Args>(args)...);
 	}
 
 private:
@@ -177,10 +179,10 @@ public:
 	{
 		if (!this->object_) {
 			T *obj = static_cast<T *>(this->obj_);
-			return (obj->*func_)(args...);
+			return (obj->*func_)(std::forward<Args>(args)...);
 		}
 
-		auto pack = std::make_shared<PackType>(args...);
+		auto pack = std::make_shared<PackType>(std::forward<Args>(args)...);
 		bool sync = BoundMethodBase::activatePack(pack, deleteMethod);
 		return sync ? pack->returnValue() : R();
 	}
@@ -188,7 +190,7 @@ public:
 	R invoke(Args... args) override
 	{
 		T *obj = static_cast<T *>(this->obj_);
-		return (obj->*func_)(args...);
+		return (obj->*func_)(std::forward<Args>(args)...);
 	}
 
 private:
@@ -209,7 +211,7 @@ public:
 
 	R activate(Args... args, [[maybe_unused]] bool deleteMethod = false) override
 	{
-		return (*func_)(args...);
+		return (*func_)(std::forward<Args>(args)...);
 	}
 
 	R invoke(Args...) override
-- 
2.48.1