#! cint

/*----------------------------------------------------------------------------

How to run the GTK-server with the C programming language, using the CINT interpreter.
This demo was requested by several people. The CINT interpreter has some limitations;
with real C code some things could have been implemented a little bit nicer.

The CINT interpreter webpage: http://root.cern.ch/root/Cint.html

Run like this:

> export CINTSYSDIR=<your cint directory>
> cint demo.c

The bidirectional pipe theory was retrieved from:
	http://www.unixwiz.net/techtips/remap-pipe-fds.html

Tested with CINT 5.16 on Slackware Linux 10.1 with GTK-server 2.0.5.

September 9, 2005 - PvE.

------------------------------------------------------------------------------*/

/* Header stuff */

#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <stdarg.h>

#define MAX_LEN 256

char *answer = (char*)malloc(MAX_LEN*sizeof(char));

int	writepipe[2],	/* parent -> child */
	readpipe [2];	/* child -> parent */

/*--------------------------------------------------*/

/* Communication function */

void gtk(int no, ...)
{
char *command;
int i;
int len;

va_list args;
va_start(args, no);

command = (char*)malloc(sizeof(char)*MAX_LEN);
strcpy(command, "");

/* Put the var_args into 1 string */
for (i = 0; i < no; i++) {
    strcat(command, va_arg(args, char*));
    strcat(command, " ");
}

/* Write to pipe */
write(writepipe[1], command, MAX_LEN);
len = read(readpipe[0], answer, MAX_LEN);

/* Make sure we do not see trash of previous answers */
answer[len] = '\0';

free(command);
va_end(args);
}

/*--------------------------------------------------*/

/* Main routine */

int main(int argc, char* argv[])
{
int result;

char *win = (char*)malloc(16*sizeof(char));
char *table = (char*)malloc(16*sizeof(char));
char *button1 = (char*)malloc(16*sizeof(char));
char *button2 = (char*)malloc(16*sizeof(char));
char *entry = (char*)malloc(16*sizeof(char));

/* First, setup pipes */
if (pipe(readpipe) < 0  ||  pipe(writepipe) < 0){
    printf("Can not create pipes!\n");
    exit(-1);
}

/* Then fork */
if((result = fork()) < 0){
    printf("Can not FORK!\n");
    exit(-1);
}

/* Child process */
else if (result == 0)
{
    /* Close the parent pipes */
    close(writepipe[1]);
    close(readpipe[0]);

    /* Duplicate STDIN and STDOUT */
    dup2(writepipe[0], 0);
    close(writepipe[0]);

    dup2(readpipe[1], 1);
    close(readpipe[1]);

    /* Start GTK-server */
    system("gtk-server -stdin");
}

/* This is the parent process */
else
{
    /* Close the child pipes first */
    close(writepipe[0]);
    close(readpipe[1]);

    /* do parent stuff */
    gtk(1, "gtk_init NULL NULL");
    gtk(1, "gtk_window_new 0");
    strcpy(win, answer);
    gtk(3, "gtk_window_set_title", win, "\"This is a title\"");
    gtk(3, "gtk_window_set_default_size", win, "100 100");
    gtk(3, "gtk_window_set_position", win, "1");
    gtk(1, "gtk_table_new 30 30 1");
    strcpy(table, answer);
    gtk(3, "gtk_container_add", win, table);
    gtk(1, "gtk_button_new_with_label Exit");
    strcpy(button1, answer);
    gtk(4, "gtk_table_attach_defaults", table, button1, "17 28 20 25");
    gtk(1, "gtk_button_new_with_label \"Print text\"");
    strcpy(button2, answer);
    gtk(4, "gtk_table_attach_defaults", table, button2, "2 13 20 25");
    gtk(1, "gtk_entry_new");
    strcpy(entry, answer);
    gtk(4, "gtk_table_attach_defaults", table, entry, "2 28 5 15");
    gtk(2, "gtk_widget_show_all", win);

/* Mainloop - CINT seems to have problems with do/while and var_args */
LABEL:
    gtk(1, "gtk_server_callback wait");

    if (!strcmp(answer, button2)){
	gtk(2, "gtk_entry_get_text", entry);
	printf("This is the contents: %s", answer);
    }
    if (strcmp(answer, win) && strcmp(answer, button1)) goto LABEL;

    /* Exit GTK-server */
    gtk(1, "gtk_server_exit");
}

return 0;
}