/*

FHE 26 Apr 2016

Readline callback interface example copied from readline documentation
and modified.
 
Compile with:

gcc -g -Wall test-callback.c -lreadline -o test-callback

*/

/* Standard include files. stdio.h is required. */
#include <stdlib.h>
#include <unistd.h>

/* Used for select(2) */
#include <sys/types.h>
#include <sys/select.h>

#include <stdio.h>

#include <errno.h>
#include <signal.h>
#include <setjmp.h>

/* Standard readline include files. */
#include <readline/readline.h>
#include <readline/history.h>

static void cb_linehandler (char *);

int running;
const char *prompt = "rltest$ ";

/******************************************************************/
/* Copied from rlprivate.h */
#define RL_CHECK_SIGNALS()                      \
	do { \
	  if (_rl_caught_signal) _rl_signal_handler (_rl_caught_signal); \
	} while (0)

extern void _rl_signal_handler (int);
extern int volatile _rl_caught_signal;
void _rl_reset_completion_state ();
/******************************************************************/


/* Callback function called for each line when accept-line executed, EOF
   seen, or EOF character read.  This sets a flag and returns; it could
   also call exit(3). */
static void
cb_linehandler (char *line)
{
    /* Can use ^D (stty eof) or `exit' to exit. */
    if (line == NULL || strcmp (line, "exit") == 0)
        {
            if (line == 0)
                printf ("\n");
            printf ("exit\n");
            /* This function needs to be called to reset the terminal settings,
               and calling it from the line handler keeps one extra prompt from
               being displayed. */
            rl_callback_handler_remove ();

            running = 0;
        }
    else
        {
            if (*line)
                add_history (line);
            printf ("input line: %s\n", line);
            free (line);
        }
}

    sigjmp_buf env;

void handle_signal(int sig) {
    /* rl_reset_line_state(); */
      /* rl_reset_after_signal (); */
      /* rl_callback_sigcleanup () */
    fprintf(stderr,"Got signal: %d\n", sig);
    siglongjmp(env,1);
}

int
main (int c, char **v)
{
    struct sigaction act;
    act.sa_handler=handle_signal;
    int res;
    res = sigaction(SIGINT, &act, NULL);
    if(res!=0) {
        perror("sigaction");
        exit(1);
    }

    if(sigsetjmp(env, 1)) {
        rl_free_line_state ();
        rl_cleanup_after_signal ();
        rl_callback_handler_remove ();
        printf("\n");
    }
    
    fd_set fds;
    int r;
    /* Install the line handler. */
    rl_callback_handler_install (prompt, cb_linehandler);
    rl_set_signals();

    /* Enter a simple event loop.  This waits until something is available
       to read on readline's input stream (defaults to standard input) and
       calls the builtin character read callback to read it.  It does not
       have to modify the user's terminal settings. */
    running = 1;
    while (running)
        {
            FD_ZERO (&fds);
            FD_SET (fileno (rl_instream), &fds);

            r = select (FD_SETSIZE, &fds, NULL, NULL, NULL);
            if (r < 0 && errno != EINTR)
                {
                    perror ("rltest: select");
                    rl_callback_handler_remove ();
                    break;
                }
            
            fprintf(stderr, "r=%d\n",r);
            
            /* RL_CHECK_SIGNALS(); */
            if (FD_ISSET (fileno (rl_instream), &fds))
                rl_callback_read_char ();
        }

    printf ("rltest: Event loop has exited\n");
    return 0;
}