event/net/ServerSocket: pass connection socket by value

UniqueSocketDescriptor is a 32-bit class, and the reference is usually
twice as large.

src/event/net/ServerSocket.hxx

@@ -69,7 +69,7 @@ protected:
 	 *
 	 * @param fd the socket owned by the callee
 	 */
-	virtual void OnAccept(UniqueSocketDescriptor &&fd,
+	virtual void OnAccept(UniqueSocketDescriptor fd,
 			      SocketAddress address) noexcept = 0;
 	virtual void OnAcceptError(std::exception_ptr ep) noexcept = 0;
 

src/event/net/TemplateServerSocket.hxx

@@ -2,11 +2,11 @@
 // Copyright CM4all GmbH
 // author: Max Kellermann <[email protected]>
 
-#ifndef TEMPLATE_SERVER_SOCKET_HXX
-#define TEMPLATE_SERVER_SOCKET_HXX
+#pragma once
 
 #include "ServerSocket.hxx"
 #include "net/SocketAddress.hxx"
+#include "net/UniqueSocketDescriptor.hxx"
 #include "util/DeleteDisposer.hxx"
 #include "util/IntrusiveList.hxx"
 #include "util/PrintException.hxx"
@@ -65,7 +65,7 @@ public:
 	}
 
 protected:
-	void OnAccept(UniqueSocketDescriptor &&_fd,
+	void OnAccept(UniqueSocketDescriptor _fd,
 		      SocketAddress address) noexcept override {
 		try {
 			auto *c = CreateConnection(std::move(_fd), address);
@@ -86,5 +86,3 @@ private:
 											      address, params);
 	}
 };
-
-#endif

src/translation/server/Listener.cxx

@@ -22,7 +22,7 @@ Listener::~Listener() noexcept
 }
 
 void
-Listener::OnAccept(UniqueSocketDescriptor &&new_fd,
+Listener::OnAccept(UniqueSocketDescriptor new_fd,
 		   SocketAddress) noexcept
 {
 	auto *connection = new Connection(GetEventLoop(),

src/translation/server/Listener.hxx

@@ -26,7 +26,7 @@ public:
 	using ServerSocket::ListenPath;
 
 private:
-	void OnAccept(UniqueSocketDescriptor &&fd,
+	void OnAccept(UniqueSocketDescriptor fd,
 		      SocketAddress address) noexcept override;
 	void OnAcceptError(std::exception_ptr ep) noexcept override;
 };

src/was/async/SimpleRun.cxx

@@ -245,12 +245,12 @@ class MultiListener final
 
 private:
 	/* virtual methods from class ServerSocket */
-	void OnAccept(UniqueSocketDescriptor &&fd,
-		      SocketAddress) noexcept {
+	void OnAccept(UniqueSocketDescriptor fd,
+		      SocketAddress) noexcept override {
 		connections.Add(GetEventLoop(), std::move(fd));
 	}
 
-	void OnAcceptError(std::exception_ptr _error) noexcept {
+	void OnAcceptError(std::exception_ptr _error) noexcept override {
 		error = std::move(_error);
 		GetEventLoop().Break();
 	}