/**
 * gcc -o xclipowner xclipowner.c -L/usr/X11R6/lib -lX11
 */
/**
 * Copyright (c) 2004 Billy Biggs <vektor@dumbterm.net>.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <stdio.h>
#include <stdint.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

/**
 * Prints the name of the Window.  I think this can be better, using
 * _NET_WM_NAME and the visible ones as appropriate.  Ideally we should
 * follow some window manager's algorithm. ??
 */
static void print_name( char *name, Display *dpy, Window win, Window root )
{
    XTextProperty nameprop;
    char *wname;

    if( XGetWMName( dpy, win, &nameprop ) ) {
        sprintf( name, "%s", nameprop.value );
        XFree( nameprop.value );
    } else if( XFetchName( dpy, win, &wname ) ) {
        sprintf( name, "%s", wname );
        XFree( wname );
    } else if( win == root ) {
        sprintf( name, "Root" );
    } else {
        sprintf( name, " " );
    }
}

int main( int argc, char **argv )
{
    Display *d = XOpenDisplay( 0 );
    char name[ 4096 ];
    Window w;
    Atom primary;
    Atom secondary;
    Atom clipboard;

    if( !d ) {
        fprintf( stderr, "Cannot open DISPLAY %s\n",
                 getenv("DISPLAY") );
        return 1;
    }

    primary = XInternAtom( d, "PRIMARY", False );
    w = XGetSelectionOwner( d, primary );
    if( !w ) {
        fprintf( stderr, "PRIMARY has no owner.\n" );
    } else {
        print_name( name, d, w, DefaultRootWindow( d ) );
        fprintf( stderr, "PRIMARY owner is 0x%x (%s)\n", (unsigned int) w, name );
    }

    secondary = XInternAtom( d, "SECONDARY", False );
    w = XGetSelectionOwner( d, secondary );
    if( !w ) {
        fprintf( stderr, "SECONDARY has no owner.\n" );
    } else {
        print_name( name, d, w, DefaultRootWindow( d ) );
        fprintf( stderr, "SECONDARY owner is 0x%x (%s)\n", (unsigned int) w, name );
    }

    clipboard = XInternAtom( d, "CLIPBOARD", False );
    w = XGetSelectionOwner( d, clipboard );
    if( !w ) {
        fprintf( stderr, "CLIPBOARD has no owner.\n" );
    } else {
        print_name( name, d, w, DefaultRootWindow( d ) );
        fprintf( stderr, "CLIPBOARD owner is 0x%x (%s)\n", (unsigned int) w, name );
    }

    XCloseDisplay(d);
    return 0;
}