putty-source/nullplug.c

/*
 * nullplug.c: provide a null implementation of the Plug vtable which
 * ignores all calls. Occasionally useful in cases where we want to
 * make a network connection just to see if it works, but not do
 * anything with it afterwards except close it again.
 */

#include "putty.h"

static void nullplug_socket_log(Plug *plug, PlugLogType type, SockAddr *addr,
                                int port, const char *err_msg, int err_code)
{
}

static void nullplug_closing(Plug *plug, const char *error_msg, int error_code,
                             bool calling_back)
{
}

static void nullplug_receive(
    Plug *plug, int urgent, const char *data, size_t len)
{
}

static void nullplug_sent(Plug *plug, size_t bufsize)
{
}

static const PlugVtable nullplug_plugvt = {
    .log = nullplug_socket_log,
    .closing = nullplug_closing,
    .receive = nullplug_receive,
    .sent = nullplug_sent,
};

static Plug nullplug_plug = { &nullplug_plugvt };

/*
 * There's a singleton instance of nullplug, because it's not
 * interesting enough to worry about making more than one of them.
 */
Plug *const nullplug = &nullplug_plug;