ServerSocket: replace callback with virtual method

src/Listen.cxx

@@ -36,16 +36,20 @@
 
 #define DEFAULT_PORT	6600
 
-static ServerSocket *listen_socket;
-int listen_port;
+class ClientListener final : public ServerSocket {
+public:
+	ClientListener():ServerSocket(*main_loop) {}
+
+private:
+	virtual void OnAccept(int fd, const sockaddr &address,
+			      size_t address_length, int uid) {
+		client_new(*main_loop, *global_partition,
+			   fd, &address, address_length, uid);
+	}
+};
 
-static void
-listen_callback(int fd, const struct sockaddr *address,
-		size_t address_length, int uid, G_GNUC_UNUSED void *ctx)
-{
-	client_new(*main_loop, *global_partition,
-		   fd, address, address_length, uid);
-}
+static ClientListener *listen_socket;
+int listen_port;
 
 static bool
 listen_add_config_param(unsigned int port,
@@ -98,7 +102,7 @@ listen_global_init(GError **error_r)
 	bool success;
 	GError *error = NULL;
 
-	listen_socket = new ServerSocket(*main_loop, listen_callback, nullptr);
+	listen_socket = new ClientListener();
 
 	if (listen_systemd_activation(&error))
 		return true;

src/event/ServerSocket.cxx

@@ -54,7 +54,7 @@
 #define DEFAULT_PORT	6600
 
 class OneServerSocket final : private SocketMonitor {
-	const ServerSocket &parent;
+	ServerSocket &parent;
 
 	const unsigned serial;
 
@@ -64,7 +64,7 @@ class OneServerSocket final : private SocketMonitor {
 	struct sockaddr *address;
 
 public:
-	OneServerSocket(EventLoop &_loop, const ServerSocket &_parent,
+	OneServerSocket(EventLoop &_loop, ServerSocket &_parent,
 			unsigned _serial,
 			const struct sockaddr *_address,
 			size_t _address_length)
@@ -176,10 +176,9 @@ OneServerSocket::Accept()
 			  (const char *)msg);
 	}
 
-	parent.callback(peer_fd,
-			(const struct sockaddr*)&peer_address,
-			peer_address_length, get_remote_uid(peer_fd),
-			parent.callback_ctx);
+	parent.OnAccept(peer_fd,
+			(const sockaddr &)peer_address,
+			peer_address_length, get_remote_uid(peer_fd));
 }
 
 bool
@@ -213,12 +212,8 @@ OneServerSocket::Open(GError **error_r)
 	return true;
 }
 
-ServerSocket::ServerSocket(EventLoop &_loop,
-			   server_socket_callback_t _callback,
-			   void *_callback_ctx)
-	:loop(_loop),
-	 callback(_callback), callback_ctx(_callback_ctx),
-	 next_serial(1) {}
+ServerSocket::ServerSocket(EventLoop &_loop)
+	:loop(_loop), next_serial(1) {}
 
 /* this is just here to allow the OneServerSocket forward
    declaration */

src/event/ServerSocket.hxx

@@ -41,16 +41,12 @@ class ServerSocket {
 
 	EventLoop &loop;
 
-	server_socket_callback_t callback;
-	void *callback_ctx;
-
 	std::forward_list<OneServerSocket> sockets;
 
 	unsigned next_serial;
 
 public:
-	ServerSocket(EventLoop &_loop,
-		     server_socket_callback_t _callback, void *_callback_ctx);
+	ServerSocket(EventLoop &_loop);
 	~ServerSocket();
 
 private:
@@ -112,6 +108,10 @@ public:
 
 	bool Open(GError **error_r);
 	void Close();
+
+protected:
+	virtual void OnAccept(int fd, const sockaddr &address,
+			      size_t address_length, int uid) = 0;
 };
 
 #endif

src/output/HttpdInternal.hxx

@@ -28,6 +28,7 @@
 #include "output_internal.h"
 #include "timer.h"
 #include "thread/Mutex.hxx"
+#include "event/ServerSocket.hxx"
 
 #include <glib.h>
 
@@ -39,7 +40,7 @@ class ServerSocket;
 class HttpdClient;
 class Page;
 
-struct HttpdOutput {
+struct HttpdOutput final : private ServerSocket {
 	struct audio_output base;
 
 	/**
@@ -79,11 +80,6 @@ struct HttpdOutput {
 	struct timer *timer;
 
 	/**
-	 * The listener socket.
-	 */
-	ServerSocket *server_socket;
-
-	/**
 	 * The header page, which is sent to every client on connect.
 	 */
 	Page *header;
@@ -201,6 +197,10 @@ struct HttpdOutput {
 	bool EncodeAndPlay(const void *chunk, size_t size, GError **error_r);
 
 	void SendTag(const struct tag *tag);
+
+private:
+	virtual void OnAccept(int fd, const sockaddr &address,
+			      size_t address_length, int uid) override;
 };
 
 #endif

src/output/HttpdOutputPlugin.cxx

@@ -28,7 +28,6 @@
 #include "Page.hxx"
 #include "IcyMetaDataServer.hxx"
 #include "fd_util.h"
-#include "event/ServerSocket.hxx"
 #include "Main.hxx"
 
 #include <assert.h>
@@ -54,14 +53,10 @@ httpd_output_quark(void)
 	return g_quark_from_static_string("httpd_output");
 }
 
-static void
-httpd_listen_in_event(int fd, const struct sockaddr *address,
-		      size_t address_length, int uid, void *ctx);
-
 inline
 HttpdOutput::HttpdOutput(EventLoop &_loop)
-	:encoder(nullptr), unflushed_input(0),
-	 server_socket(new ServerSocket(_loop, httpd_listen_in_event, this)),
+	:ServerSocket(_loop),
+	 encoder(nullptr), unflushed_input(0),
 	 metadata(nullptr)
 {
 }
@@ -74,8 +69,6 @@ HttpdOutput::~HttpdOutput()
 	if (encoder != nullptr)
 		encoder_finish(encoder);
 
-	delete server_socket;
-
 }
 
 inline bool
@@ -84,7 +77,7 @@ HttpdOutput::Bind(GError **error_r)
 	open = false;
 
 	const ScopeLock protect(mutex);
-	return server_socket->Open(error_r);
+	return ServerSocket::Open(error_r);
 }
 
 inline void
@@ -93,7 +86,7 @@ HttpdOutput::Unbind()
 	assert(!open);
 
 	const ScopeLock protect(mutex);
-	server_socket->Close();
+	ServerSocket::Close();
 }
 
 inline bool
@@ -125,8 +118,8 @@ HttpdOutput::Configure(const config_param *param, GError **error_r)
 		config_get_block_string(param, "bind_to_address", NULL);
 	bool success = bind_to_address != NULL &&
 		strcmp(bind_to_address, "any") != 0
-		? server_socket->AddHost(bind_to_address, port, error_r)
-		: server_socket->AddPort(port, error_r);
+		? AddHost(bind_to_address, port, error_r)
+		: AddPort(port, error_r);
 	if (!success)
 		return false;
 
@@ -165,12 +158,21 @@ httpd_output_init(const struct config_param *param,
 	return &httpd->base;
 }
 
+#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Winvalid-offsetof"
+#endif
+
 static inline constexpr HttpdOutput *
 Cast(audio_output *ao)
 {
 	return (HttpdOutput *)((char *)ao - offsetof(HttpdOutput, base));
 }
 
+#if GCC_CHECK_VERSION(4,6) || defined(__clang__)
+#pragma GCC diagnostic pop
+#endif
+
 static void
 httpd_output_finish(struct audio_output *ao)
 {
@@ -196,18 +198,16 @@ HttpdOutput::AddClient(int fd)
 		clients.front().PushMetaData(metadata);
 }
 
-static void
-httpd_listen_in_event(int fd, const struct sockaddr *address,
-		      size_t address_length, G_GNUC_UNUSED int uid, void *ctx)
+void
+HttpdOutput::OnAccept(int fd, const sockaddr &address,
+		      size_t address_length, gcc_unused int uid)
 {
-	HttpdOutput *httpd = (HttpdOutput *)ctx;
-
 	/* the listener socket has become readable - a client has
 	   connected */
 
 #ifdef HAVE_LIBWRAP
-	if (address->sa_family != AF_UNIX) {
-		char *hostaddr = sockaddr_to_string(address, address_length, NULL);
+	if (address.sa_family != AF_UNIX) {
+		char *hostaddr = sockaddr_to_string(&address, address_length, NULL);
 		const char *progname = g_get_prgname();
 
 		struct request_info req;
@@ -231,14 +231,12 @@ httpd_listen_in_event(int fd, const struct sockaddr *address,
 	(void)address_length;
 #endif	/* HAVE_WRAP */
 
-	const ScopeLock protect(httpd->mutex);
+	const ScopeLock protect(mutex);
 
 	if (fd >= 0) {
 		/* can we allow additional client */
-		if (httpd->open &&
-		    (httpd->clients_max == 0 ||
-		     httpd->clients_cnt < httpd->clients_max))
-			httpd->AddClient(fd);
+		if (open && (clients_max == 0 ||  clients_cnt < clients_max))
+			AddClient(fd);
 		else
 			close_socket(fd);
 	} else if (fd < 0 && errno != EINTR) {