Remove release_back_to_server

src/connection_handler.hpp

@@ -26,21 +26,21 @@ public:
    * Process incoming data from a connection.
    *
    * @param data Incoming data buffer (may be partial message)
-   * @param conn_ptr Unique pointer to connection - handler can take ownership
-   * by releasing it
+   * @param conn Connection reference - server retains ownership
    *
    * Implementation should:
-   * - Parse incoming data using arena allocator when needed
-   * - Use conn_ptr->append_message() to queue response data to be sent
+   * - Create request-scoped Arena for parsing and response generation
+   * - Parse incoming data using the request arena
+   * - Use conn.append_message() to queue response data to be sent
    * - Handle partial messages and streaming protocols appropriately
-   * - Can take ownership by calling conn_ptr.release() to pass to other threads
-   * - If ownership is taken, handler must call Server::release_back_to_server()
-   * when done
-   * @note `data` is *not* owned by the connection arena, and its lifetime ends
-   * after the call to on_data_arrived.
+   * - Use conn.get_weak_ref() for async processing if needed
+   *
+   * @note `data` lifetime ends after the call to on_data_arrived.
    * @note May be called from an arbitrary server thread.
+   * @note Handler can safely access connection concurrently via thread-safe
+   * methods.
    */
-  virtual void on_data_arrived(std::string_view /*data*/, Ref<Connection> &) {};
+  virtual void on_data_arrived(std::string_view /*data*/, Connection &) {};
 
   /**
    * Called when data has been successfully written to the connection.
@@ -50,29 +50,26 @@ public:
    * - Implementing backpressure for continuous data streams
    * - Progress monitoring for long-running transfers
    *
-   * @param conn_ptr Connection that made write progress - handler can take
-   * ownership
+   * @param conn Connection that made write progress - server retains ownership
    * @note May be called from an arbitrary server thread.
    * @note Called during writes, not necessarily when buffer becomes empty
    */
-  virtual void on_write_progress(Ref<Connection> &) {}
+  virtual void on_write_progress(Connection &) {}
 
   /**
    * Called when the connection's outgoing write buffer becomes empty.
    *
    * This indicates all queued messages have been successfully written
    * to the socket. Useful for:
-   * - Resetting arena allocators safely
    * - Implementing keep-alive connection reuse
    * - Closing connections after final response
    * - Relieving backpressure conditions
    *
-   * @param conn_ptr Connection with empty write buffer - handler can take
-   * ownership
+   * @param conn Connection with empty write buffer - server retains ownership
    * @note May be called from an arbitrary server thread.
    * @note Only called on transitions from non-empty → empty buffer
    */
-  virtual void on_write_buffer_drained(Ref<Connection> &) {}
+  virtual void on_write_buffer_drained(Connection &) {}
 
   /**
    * Called when a new connection is established.
@@ -101,11 +98,9 @@ public:
    *
    * This hook is called after on_data_arrived, on_write_progress, or
    * on_write_buffer_drained has been called for each connection in the batch.
-   * The handler can take ownership of the connections by moving the unique_ptr
-   * out of the span. Any connections left in the span will remain owned by the
-   * server.
+   * All connections remain server-owned.
    *
-   * @param batch A span of unique_ptrs to the connections in the batch.
+   * @param batch A span of connection references in the batch.
    */
-  virtual void on_batch_complete(std::span<Ref<Connection>> /*batch*/) {}
+  virtual void on_batch_complete(std::span<Connection *> /*batch*/) {}
 };