From 5e5c8f86b60a8018e8801fb44bbe56ce97d9deef Mon Sep 17 00:00:00 2001
From: Anthony Towns <aj@erisian.com.au>
Date: Mon, 11 Sep 2023 18:36:11 +1000
Subject: [PATCH] serialize: add SER_PARAMS_OPFUNC

---
 src/netaddress.h |  1 +
 src/protocol.h   |  1 +
 src/serialize.h  | 13 +++++++++++++
 3 files changed, 15 insertions(+)

diff --git a/src/netaddress.h b/src/netaddress.h
index a0944c886fc..7d3659a11af 100644
--- a/src/netaddress.h
+++ b/src/netaddress.h
@@ -218,6 +218,7 @@ public:
     };
     struct SerParams {
         const Encoding enc;
+        SER_PARAMS_OPFUNC
     };
     static constexpr SerParams V1{Encoding::V1};
     static constexpr SerParams V2{Encoding::V2};
diff --git a/src/protocol.h b/src/protocol.h
index a7ca0c6f3e3..e1caba766ff 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -396,6 +396,7 @@ public:
     };
     struct SerParams : CNetAddr::SerParams {
         const Format fmt;
+        SER_PARAMS_OPFUNC
     };
     static constexpr SerParams V1_NETWORK{{CNetAddr::Encoding::V1}, Format::Network};
     static constexpr SerParams V2_NETWORK{{CNetAddr::Encoding::V2}, Format::Network};
diff --git a/src/serialize.h b/src/serialize.h
index 7e4788a5ca2..04b29d1ded2 100644
--- a/src/serialize.h
+++ b/src/serialize.h
@@ -1192,4 +1192,17 @@ static auto WithParams(const Params& params, T&& t)
     return ParamsWrapper<Params, T>{params, t};
 }
 
+/**
+ * Helper macro for SerParams structs
+ *
+ * Allows you define SerParams instances and then apply them directly
+ * to an object via function call syntax, eg:
+ *
+ *   constexpr SerParams FOO{....};
+ *   ss << FOO(obj);
+ */
+#define SER_PARAMS_OPFUNC \
+    template <typename T> \
+    auto operator()(T&& t) const { return WithParams(*this, t); }
+
 #endif // BITCOIN_SERIALIZE_H