From 75c5d220dece649e712f3aa4e1daae3d9e3e389e Mon Sep 17 00:00:00 2001
From: Abtin Keshavarzian <abtink@google.com>
Date: Fri, 7 Nov 2025 14:22:27 -0800
Subject: [PATCH] [border-agent] inline `ForwardContext::ToHeader()` (#12118)

Remove the `CoapDtlsSession::ForwardContext::ToHeader()` helper method
and move its logic directly into the `HandleCoapResponse()` method.
This simplifies the implementation by removing an unnecessary function
call for a single-use case.

Additionally, convert `ForwardContext` from a `class` to a `struct`.
This change makes the constructor public, removing the need for a
`friend` declaration for `Heap::Allocatable`, and better reflects its
role as a simple data structure.
---
 src/core/meshcop/border_agent.cpp | 11 +++--------
 src/core/meshcop/border_agent.hpp | 14 ++++----------
 2 files changed, 7 insertions(+), 18 deletions(-)

diff --git a/src/core/meshcop/border_agent.cpp b/src/core/meshcop/border_agent.cpp
index b2a1c4509..7fabc27ec 100644
--- a/src/core/meshcop/border_agent.cpp
+++ b/src/core/meshcop/border_agent.cpp
@@ -1106,7 +1106,9 @@ void Manager::CoapDtlsSession::HandleLeaderResponseToFwdTmf(const ForwardContext
         }
     }
 
-    SuccessOrExit(error = aForwardContext.ToHeader(*forwardMessage, aResponse->GetCode()));
+    forwardMessage->Init(Coap::kTypeNonConfirmable, static_cast<Coap::Code>(aResponse->GetCode()));
+
+    SuccessOrExit(error = forwardMessage->SetToken(aForwardContext.mToken, aForwardContext.mTokenLength));
 
     if (aResponse->GetLength() > aResponse->GetOffset())
     {
@@ -1357,13 +1359,6 @@ Manager::CoapDtlsSession::ForwardContext::ForwardContext(CoapDtlsSession     &aS
     memcpy(mToken, aMessage.GetToken(), mTokenLength);
 }
 
-Error Manager::CoapDtlsSession::ForwardContext::ToHeader(Coap::Message &aMessage, uint8_t aCode) const
-{
-    aMessage.Init(Coap::kTypeNonConfirmable, static_cast<Coap::Code>(aCode));
-
-    return aMessage.SetToken(mToken, mTokenLength);
-}
-
 } // namespace BorderAgent
 } // namespace MeshCoP
 } // namespace ot
diff --git a/src/core/meshcop/border_agent.hpp b/src/core/meshcop/border_agent.hpp
index 4f03e4bf5..3593be66b 100644
--- a/src/core/meshcop/border_agent.hpp
+++ b/src/core/meshcop/border_agent.hpp
@@ -262,23 +262,17 @@ private:
         uint64_t GetAllocationTime(void) const { return mAllocationTime; }
 
     private:
-        class ForwardContext : public ot::LinkedListEntry<ForwardContext>,
-                               public Heap::Allocatable<ForwardContext>,
-                               private ot::NonCopyable
+        struct ForwardContext : public ot::LinkedListEntry<ForwardContext>,
+                                public Heap::Allocatable<ForwardContext>,
+                                private ot::NonCopyable
         {
-            friend class Heap::Allocatable<ForwardContext>;
-
-        public:
-            Error ToHeader(Coap::Message &aMessage, uint8_t aCode) const;
+            ForwardContext(CoapDtlsSession &aSession, const Coap::Message &aMessage, Uri aUri);
 
             CoapDtlsSession &mSession;
             ForwardContext  *mNext;
             Uri              mUri;
             uint8_t          mTokenLength;
             uint8_t          mToken[Coap::Message::kMaxTokenLength];
-
-        private:
-            ForwardContext(CoapDtlsSession &aSession, const Coap::Message &aMessage, Uri aUri);
         };
 
         CoapDtlsSession(Instance &aInstance, Dtls::Transport &aDtlsTransport);