emacs/lwlib/lwlib.c

/* A general interface to the widgets of different toolkits.
   Copyright (C) 1992, 1993 Lucid, Inc.

This file is part of the Lucid Widget Library.

The Lucid Widget Library is free software; you can redistribute it and/or 
modify it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.

The Lucid Widget Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of 
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#ifdef NeXT
#undef __STRICT_BSD__ /* ick */
#endif

#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <string.h>
#include <stdio.h>
#include <X11/StringDefs.h>
#include "lwlib-int.h"
#include "lwlib-utils.h"

#if defined(__GNUC__) && !defined(alloca)
#define alloca __builtin_alloca
#endif

#if ((!__GNUC__) && !defined(__hpux)) && !defined(AIXV3)
#include <alloca.h>
#endif

#if defined(AIXV3)
#pragma alloca
#endif

#if defined (USE_LUCID)
#include "lwlib-Xlw.h"
#endif
#if defined (USE_MOTIF)
#include "lwlib-Xm.h"
#endif
#if defined (USE_OLIT)
#include "lwlib-Xol.h"
#endif

#if !defined (USE_LUCID) && !defined (USE_MOTIF) && !defined (USE_OLIT)
ERROR!  At least one of USE_LUCID, USE_MOTIF or USE_OLIT must be defined.
#endif

#if defined (USE_MOTIF) && defined (USE_OLIT)
ERROR! no more than one of USE_MOTIF and USE_OLIT may be defined.
#endif

/* List of all widgets managed by the library. */
static widget_info*
all_widget_info = NULL;

/* Forward declarations */
static void
instanciate_widget_instance (widget_instance* instance);

/* utility functions for widget_instance and widget_info */
static char *
safe_strdup (char* s)
{
  char *result;
  if (! s) return 0;
  result = (char *) malloc (strlen (s) + 1);
  if (! result)
    return 0;
  strcpy (result, s);
  return result;
}

static void
safe_free_str (char* s)
{
  if (s) free (s);
}

static widget_value *widget_value_free_list = 0;

widget_value *
malloc_widget_value ()
{
  widget_value *wv;
  if (widget_value_free_list)
    {
      wv = widget_value_free_list;
      widget_value_free_list = wv->free_list;
      wv->free_list = 0;
    }
  else
    {
      wv = (widget_value *) malloc (sizeof (widget_value));
    }
  memset (wv, 0, sizeof (widget_value));
  return wv;
}

/* this is analagous to free().  It frees only what was allocated
   by malloc_widget_value(), and no substructures. 
 */
void
free_widget_value (wv)
     widget_value *wv;
{
  if (wv->free_list)
    abort ();
  wv->free_list = widget_value_free_list;
  widget_value_free_list = wv;
}

static void
free_widget_value_tree (widget_value* wv)
{
  if (!wv)
    return;

  if (wv->name) free (wv->name);
  if (wv->value) free (wv->value);
  if (wv->key) free (wv->key);

  wv->name = wv->value = wv->key = (char *) 0xDEADBEEF;

  if (wv->toolkit_data && wv->free_toolkit_data)
    {
      free (wv->toolkit_data);
      wv->toolkit_data = (void *) 0xDEADBEEF;
    }

  if (wv->contents && (wv->contents != (widget_value*)1))
    {
      free_widget_value_tree (wv->contents);
      wv->contents = (widget_value *) 0xDEADBEEF;
    }
  if (wv->next)
    {
      free_widget_value_tree (wv->next);
      wv->next = (widget_value *) 0xDEADBEEF;
    }
  free_widget_value (wv);
}

static widget_value *
copy_widget_value_tree (widget_value* val, change_type change)
{
  widget_value* copy;
  
  if (!val)
    return NULL;
  if (val == (widget_value *) 1)
    return val;

  copy = malloc_widget_value ();
  copy->name = safe_strdup (val->name);
  copy->value = safe_strdup (val->value);
  copy->key = safe_strdup (val->key);
  copy->enabled = val->enabled;
  copy->selected = val->selected;
  copy->edited = False;
  copy->change = change;
  copy->contents = copy_widget_value_tree (val->contents, change);
  copy->call_data = val->call_data;
  copy->next = copy_widget_value_tree (val->next, change);
  copy->toolkit_data = NULL;
  copy->free_toolkit_data = False;
  return copy;
}

static widget_info *
allocate_widget_info (char* type, char* name, LWLIB_ID id, widget_value* val,
		      lw_callback pre_activate_cb, lw_callback selection_cb,
		      lw_callback post_activate_cb)
{
  widget_info* info = (widget_info*)malloc (sizeof (widget_info));
  info->type = safe_strdup (type);
  info->name = safe_strdup (name);
  info->id = id;
  info->val = copy_widget_value_tree (val, STRUCTURAL_CHANGE);
  info->busy = False;
  info->pre_activate_cb = pre_activate_cb;
  info->selection_cb = selection_cb;
  info->post_activate_cb = post_activate_cb;
  info->instances = NULL;

  info->next = all_widget_info;
  all_widget_info = info;

  return info;
}

static void
free_widget_info (widget_info* info)
{
  safe_free_str (info->type);
  safe_free_str (info->name);
  free_widget_value_tree (info->val);
  memset ((void*)info, 0xDEADBEEF, sizeof (widget_info));
  free (info);
}

static void
mark_widget_destroyed (Widget widget, XtPointer closure, XtPointer call_data)
{
  widget_instance* instance = (widget_instance*)closure;

  /* be very conservative */
  if (instance->widget == widget)
    instance->widget = NULL;
}

static widget_instance *
allocate_widget_instance (widget_info* info, Widget parent, Boolean pop_up_p)
{
  widget_instance* instance =
    (widget_instance*)malloc (sizeof (widget_instance));
  instance->parent = parent;
  instance->pop_up_p = pop_up_p;
  instance->info = info;
  instance->next = info->instances;
  info->instances = instance;

  instanciate_widget_instance (instance);

  XtAddCallback (instance->widget, XtNdestroyCallback,
		 mark_widget_destroyed, (XtPointer)instance);
  return instance;
}

static void
free_widget_instance (widget_instance* instance)
{
  memset ((void*)instance, 0xDEADBEEF, sizeof (widget_instance));
  free (instance);
}

static widget_info *
get_widget_info (LWLIB_ID id, Boolean remove_p)
{
  widget_info* info;
  widget_info* prev;
  for (prev = NULL, info = all_widget_info;
       info;
       prev = info, info = info->next)
    if (info->id == id)
     {
       if (remove_p)
	 {
	   if (prev)
	     prev->next = info->next;
	   else
	     all_widget_info = info->next;
	 }
      return info;
     }
  return NULL;
}

static widget_instance *
get_widget_instance (Widget widget, Boolean remove_p)
{
  widget_info* info;
  widget_instance* instance;
  widget_instance* prev;
  for (info = all_widget_info; info; info = info->next)
    for (prev = NULL, instance = info->instances;
	 instance;
	 prev = instance, instance = instance->next)
      if (instance->widget == widget)
	{
	  if (remove_p)
	    {
	      if (prev)
		prev->next = instance->next;
	      else
		info->instances = instance->next;
	    }
	  return instance;
	}
  return (widget_instance *) 0;
}

static widget_instance*
find_instance (LWLIB_ID id, Widget parent, Boolean pop_up_p)
{
  widget_info* info = get_widget_info (id, False);
  widget_instance* instance;

  if (info)
    for (instance = info->instances; instance; instance = instance->next)
      if (instance->parent == parent && instance->pop_up_p == pop_up_p)
	return instance;

  return NULL;
}


/* utility function for widget_value */
static Boolean
safe_strcmp (char* s1, char* s2)
{
  if (!!s1 ^ !!s2) return True;
  return (s1 && s2) ? strcmp (s1, s2) : s1 ? False : !!s2;
}

static int
max (int i1, int i2)
{
  return i1 > i2 ? i1 : i2;
}


#if 0
# define EXPLAIN(name, oc, nc, desc, a1, a2)				\
   printf ("Change: \"%s\"\tmax(%s=%d,%s=%d)\t%s %d %d\n",		\
	   name,							\
	   (oc == NO_CHANGE ? "none" :					\
	    (oc == INVISIBLE_CHANGE ? "invisible" :			\
	     (oc == VISIBLE_CHANGE ? "visible" :			\
	      (oc == STRUCTURAL_CHANGE ? "structural" : "???")))),	\
	   oc,								\
	   (nc == NO_CHANGE ? "none" :					\
	    (nc == INVISIBLE_CHANGE ? "invisible" :			\
	     (nc == VISIBLE_CHANGE ? "visible" :			\
	      (nc == STRUCTURAL_CHANGE ? "structural" : "???")))),	\
	   nc, desc, a1, a2)
#else
# define EXPLAIN(name, oc, nc, desc, a1, a2)
#endif


static widget_value *
merge_widget_value (widget_value* val1, widget_value* val2, int level)
{
  change_type change;
  widget_value* merged_next;
  widget_value* merged_contents;

  if (!val1)
    {
      if (val2)
	return copy_widget_value_tree (val2, STRUCTURAL_CHANGE);
      else
	return NULL;
    }
  if (!val2)
    {
      free_widget_value_tree (val1);
      return NULL;
    }
  
  change = NO_CHANGE;

  if (safe_strcmp (val1->name, val2->name))
    {
      EXPLAIN (val1->name, change, STRUCTURAL_CHANGE, "name change",
	       val1->name, val2->name);
      change = max (change, STRUCTURAL_CHANGE);
      safe_free_str (val1->name);
      val1->name = safe_strdup (val2->name);
    }
  if (safe_strcmp (val1->value, val2->value))
    {
      EXPLAIN (val1->name, change, VISIBLE_CHANGE, "value change",
	       val1->value, val2->value);
      change = max (change, VISIBLE_CHANGE);
      safe_free_str (val1->value);
      val1->value = safe_strdup (val2->value);
    }
  if (safe_strcmp (val1->key, val2->key))
    {
      EXPLAIN (val1->name, change, VISIBLE_CHANGE, "key change",
	       val1->key, val2->key);
      change = max (change, VISIBLE_CHANGE);
      safe_free_str (val1->key);
      val1->key = safe_strdup (val2->key);
    }
  if (val1->enabled != val2->enabled)
    {
      EXPLAIN (val1->name, change, VISIBLE_CHANGE, "enablement change",
	       val1->enabled, val2->enabled);
      change = max (change, VISIBLE_CHANGE);
      val1->enabled = val2->enabled;
    }
  if (val1->selected != val2->selected)
    {
      EXPLAIN (val1->name, change, VISIBLE_CHANGE, "selection change",
	       val1->selected, val2->selected);
      change = max (change, VISIBLE_CHANGE);
      val1->selected = val2->selected;
    }
  if (val1->call_data != val2->call_data)
    {
      EXPLAIN (val1->name, change, INVISIBLE_CHANGE, "call-data change",
	       val1->call_data, val2->call_data);
      change = max (change, INVISIBLE_CHANGE);
      val1->call_data = val2->call_data;
    }

  if (level > 0)
    {
      merged_contents =
	merge_widget_value (val1->contents, val2->contents, level - 1);
      
      if (val1->contents && !merged_contents)
	{
	  EXPLAIN (val1->name, change, INVISIBLE_CHANGE, "(contents gone)",
		   0, 0);
	  change = max (change, INVISIBLE_CHANGE);
	}
      else if (merged_contents && merged_contents->change != NO_CHANGE)
	{
	  EXPLAIN (val1->name, change, INVISIBLE_CHANGE, "(contents change)",
		   0, 0);
	  change = max (change, INVISIBLE_CHANGE);
	}
      
      val1->contents = merged_contents;
    }

  merged_next = merge_widget_value (val1->next, val2->next, level);

  if (val1->next && !merged_next)
    {
      EXPLAIN (val1->name, change, STRUCTURAL_CHANGE, "(following gone)",
	       0, 0);
      change = max (change, STRUCTURAL_CHANGE);
    }
  else if (merged_next)
    {
      if (merged_next->change)
	EXPLAIN (val1->name, change, merged_next->change, "(following change)",
		 0, 0);
      change = max (change, merged_next->change);
    }

  val1->next = merged_next;

  val1->change = change;
  
  if (change > NO_CHANGE && val1->toolkit_data)
    {
      if (val1->free_toolkit_data)
	free (val1->toolkit_data);
      val1->toolkit_data = NULL;
    }

  return val1;
}


/* modifying the widgets */
static Widget
name_to_widget (widget_instance* instance, char* name)
{
  Widget widget = NULL;

  if (!instance->widget)
    return NULL;

  if (!strcmp (XtName (instance->widget), name))
    widget = instance->widget;
  else
    {
      int length = strlen (name) + 2;
      char* real_name = (char *) alloca (length);
      real_name [0] = '*';
      strcpy (real_name + 1, name);
      
      widget = XtNameToWidget (instance->widget, real_name);
    }
  return widget;
}

static void
set_one_value (widget_instance* instance, widget_value* val, Boolean deep_p)
{
  Widget widget = name_to_widget (instance, val->name);
  
  if (widget)
    {
#if defined (USE_LUCID)
      if (lw_lucid_widget_p (instance->widget))
	xlw_update_one_widget (instance, widget, val, deep_p);
#endif
#if defined (USE_MOTIF)
      if (lw_motif_widget_p (instance->widget))
	xm_update_one_widget (instance, widget, val, deep_p);
#endif
#if defined (USE_OLIT)
      if (lw_olit_widget_p (instance->widget))
	xol_update_one_widget (instance, widget, val, deep_p);
#endif
    }
}

static void
update_one_widget_instance (widget_instance* instance, Boolean deep_p)
{
  widget_value *val;

  if (!instance->widget)
    /* the widget was destroyed */
    return;

  for (val = instance->info->val; val; val = val->next)
    if (val->change != NO_CHANGE)
      set_one_value (instance, val, deep_p);
}

static void
update_all_widget_values (widget_info* info, Boolean deep_p)
{
  widget_instance* instance;
  widget_value* val;

  for (instance = info->instances; instance; instance = instance->next)
    update_one_widget_instance (instance, deep_p);

  for (val = info->val; val; val = val->next)
    val->change = NO_CHANGE;
}

void
lw_modify_all_widgets (LWLIB_ID id, widget_value* val, Boolean deep_p)
{
  widget_info* info = get_widget_info (id, False);
  widget_value* new_val;
  widget_value* next_new_val;
  widget_value* cur;
  widget_value* prev;
  widget_value* next;
  int		found;

  if (!info)
    return;

  for (new_val = val; new_val; new_val = new_val->next)
    {
      next_new_val = new_val->next;
      new_val->next = NULL;
      found = False;
      for (prev = NULL, cur = info->val; cur; prev = cur, cur = cur->next)
	if (!strcmp (cur->name, new_val->name))
	  {
	    found = True;
	    next = cur->next;
	    cur->next = NULL;
	    cur = merge_widget_value (cur, new_val, deep_p ? 1000 : 1);
	    if (prev)
	      prev->next = cur ? cur : next;
	    else
	      info->val = cur ? cur : next;
	    if (cur)
	      cur->next = next;
	    break;
	  }
      if (!found)
	{
	  /* Could not find it, add it */
	  if (prev)
	    prev->next = copy_widget_value_tree (new_val, STRUCTURAL_CHANGE);
	  else
	    info->val = copy_widget_value_tree (new_val, STRUCTURAL_CHANGE);
	}
      new_val->next = next_new_val;
    }

  update_all_widget_values (info, deep_p);
}


/* creating the widgets */

static void
initialize_widget_instance (widget_instance* instance)
{
  widget_value* val;

  for (val = instance->info->val; val; val = val->next)
    val->change = STRUCTURAL_CHANGE;

  update_one_widget_instance (instance, True);

  for (val = instance->info->val; val; val = val->next)
    val->change = NO_CHANGE;
}


static widget_creation_function
find_in_table (char* type, widget_creation_entry* table)
{
  widget_creation_entry* cur;
  for (cur = table; cur->type; cur++)
    if (!strcasecmp (type, cur->type))
      return cur->function;
  return NULL;
}

static Boolean
dialog_spec_p (char* name)
{
  /* return True if name matches [EILPQeilpq][1-9][Bb] or 
     [EILPQeilpq][1-9][Bb][Rr][1-9] */
  if (!name)
    return False;
  
  switch (name [0])
    {
    case 'E': case 'I': case 'L': case 'P': case 'Q':
    case 'e': case 'i': case 'l': case 'p': case 'q':
      if (name [1] >= '0' && name [1] <= '9')
	{
	  if (name [2] != 'B' && name [2] != 'b')
	    return False;
	  if (!name [3])
	    return True;
	  if ((name [3] == 'T' || name [3] == 't') && !name [4])
	    return True;
	  if ((name [3] == 'R' || name [3] == 'r')
	      && name [4] >= '0' && name [4] <= '9' && !name [5])
	    return True;
	  return False;
	}
      else
	return False;
    
    default:
      return False;
    }
}

static void
instanciate_widget_instance (widget_instance* instance)
{
  widget_creation_function function = NULL;

#if defined (USE_LUCID)
  if (!function)
    function = find_in_table (instance->info->type, xlw_creation_table);
#endif
#if defined(USE_MOTIF)
  if (!function)
    function = find_in_table (instance->info->type, xm_creation_table);
#endif
#if defined (USE_OLIT)
  if (!function)
    function = find_in_table (instance->info->type, xol_creation_table);
#endif

  if (!function)
    {
      if (dialog_spec_p (instance->info->type))
	{
#if defined (USE_LUCID)
	  /* not yet */
#endif
#if defined(USE_MOTIF)
	  if (!function)
	    function = xm_create_dialog;
#endif
#if defined (USE_OLIT)
	  /* not yet */
#endif
	}
    }
  
  if (!function)
    {
      printf ("No creation function for widget type %s\n",
	      instance->info->type);
      abort ();
    }

  instance->widget = (*function) (instance);

  if (!instance->widget)
    abort ();

  /*   XtRealizeWidget (instance->widget);*/
}

void 
lw_register_widget (char* type, char* name, LWLIB_ID id, widget_value* val,
		    lw_callback pre_activate_cb, lw_callback selection_cb,
		    lw_callback post_activate_cb)
{
  if (!get_widget_info (id, False))
    allocate_widget_info (type, name, id, val, pre_activate_cb, selection_cb,
			  post_activate_cb);
}

Widget
lw_get_widget (LWLIB_ID id, Widget parent, Boolean pop_up_p)
{
  widget_instance* instance;
  
  instance = find_instance (id, parent, pop_up_p);
  return instance ? instance->widget : NULL;
}

Widget
lw_make_widget (LWLIB_ID id, Widget parent, Boolean pop_up_p)
{
  widget_instance* instance;
  widget_info* info;
  
  instance = find_instance (id, parent, pop_up_p);
  if (!instance)
    {
      info = get_widget_info (id, False);
      if (!info)
	return NULL;
      instance = allocate_widget_instance (info, parent, pop_up_p);
      initialize_widget_instance (instance);
    }
  if (!instance->widget)
    abort ();
  return instance->widget;
}

Widget
lw_create_widget (char* type, char* name, LWLIB_ID id, widget_value* val,
		  Widget parent, Boolean pop_up_p, lw_callback pre_activate_cb,
		  lw_callback selection_cb, lw_callback post_activate_cb)
{
  lw_register_widget (type, name, id, val, pre_activate_cb, selection_cb,
		      post_activate_cb);
  return lw_make_widget (id, parent, pop_up_p);
}
		  

/* destroying the widgets */
static void
destroy_one_instance (widget_instance* instance)
{
  /* Remove the destroy callback on the widget; that callback will try to
     dereference the instance object (to set its widget slot to 0, since the
     widget is dead.)  Since the instance is now dead, we don't have to worry
     about the fact that its widget is dead too.

     This happens in the Phase2Destroy of the widget, so this callback would
     not have been run until arbitrarily long after the instance was freed.
   */
  if (instance->widget)
    XtRemoveCallback (instance->widget, XtNdestroyCallback,
		      mark_widget_destroyed, (XtPointer)instance);

  if (instance->widget)
    {
      /* The else are pretty tricky here, including the empty statement
	 at the end because it would be very bad to destroy a widget
	 twice. */
#if defined (USE_LUCID)
      if (lw_lucid_widget_p (instance->widget))
	xlw_destroy_instance (instance);
      else
#endif
#if defined (USE_MOTIF)
      if (lw_motif_widget_p (instance->widget))
	xm_destroy_instance (instance);
      else
#endif
#if defined (USE_OLIT)
      if (lw_olit_widget_p (instance->widget))
	xol_destroy_instance (instance);
      else
#endif
	/* do not remove the empty statement */
	;
    }

  free_widget_instance (instance);
}

void
lw_destroy_widget (Widget w)
{
  widget_instance* instance = get_widget_instance (w, True);
  
  if (instance)
    {
      widget_info *info = instance->info;
      /* instance has already been removed from the list; free it */
      destroy_one_instance (instance);
      /* if there are no instances left, free the info too */
      if (!info->instances)
	lw_destroy_all_widgets (info->id);
    }
}

void
lw_destroy_all_widgets (LWLIB_ID id)
{
  widget_info* info = get_widget_info (id, True);
  widget_instance* instance;
  widget_instance* next;

  if (info)
    {
      for (instance = info->instances; instance; )
	{
	  next = instance->next;
	  destroy_one_instance (instance);
	  instance = next;
	}
      free_widget_info (info);
    }
}

void
lw_destroy_everything ()
{
  while (all_widget_info)
    lw_destroy_all_widgets (all_widget_info->id);
}

void
lw_destroy_all_pop_ups ()
{
  widget_info* info;
  widget_info* next;
  widget_instance* instance;

  for (info = all_widget_info; info; info = next)
    {
      next = info->next;
      instance = info->instances;
      if (instance && instance->pop_up_p)
	lw_destroy_all_widgets (info->id);
    }
}

#ifdef USE_MOTIF
extern Widget first_child (Widget);	/* garbage */
#endif

Widget
lw_raise_all_pop_up_widgets ()
{
  widget_info* info;
  widget_instance* instance;
  Widget result = NULL;

  for (info = all_widget_info; info; info = info->next)
    for (instance = info->instances; instance; instance = instance->next)
      if (instance->pop_up_p)
	{
	  Widget widget = instance->widget;
	  if (widget)
	    {
	      if (XtIsManaged (widget)
#ifdef USE_MOTIF
		  /* What a complete load of crap!!!!
		     When a dialogShell is on the screen, it is not managed!
		   */
		  || (lw_motif_widget_p (instance->widget) &&
		      XtIsManaged (first_child (widget)))
#endif
		  )
		{
		  if (!result)
		    result = widget;
		  XMapRaised (XtDisplay (widget), XtWindow (widget));
		}
	    }
	}
  return result;
}

static void
lw_pop_all_widgets (LWLIB_ID id, Boolean up)
{
  widget_info* info = get_widget_info (id, False);
  widget_instance* instance;

  if (info)
    for (instance = info->instances; instance; instance = instance->next)
      if (instance->pop_up_p && instance->widget)
	{
	  if (!XtIsRealized (instance->widget))
	    XtRealizeWidget (instance->widget);
#if defined (USE_LUCID)
	  if (lw_lucid_widget_p (instance->widget))
	    xlw_pop_instance (instance, up);
#endif
#if defined (USE_MOTIF)
	  if (lw_motif_widget_p (instance->widget))
	    xm_pop_instance (instance, up);
#endif
#if defined (USE_OLIT)
	  if (lw_olit_widget_p (instance->widget))
	    xol_pop_instance (instance, up);
#endif
	}
}

void
lw_pop_up_all_widgets (LWLIB_ID id)
{
  lw_pop_all_widgets (id, True);
}

void
lw_pop_down_all_widgets (LWLIB_ID id)
{
  lw_pop_all_widgets (id, False);
}

void
lw_popup_menu (Widget widget)
{
#if defined (USE_LUCID)
  if (lw_lucid_widget_p (widget))
    xlw_popup_menu (widget);
#endif
#if defined (USE_MOTIF)
  if (lw_motif_widget_p (widget))
    xm_popup_menu (widget);
#endif
#if defined (USE_OLIT)
  if (lw_olit_widget_p (widget))
    xol_popup_menu (widget);
#endif
}

/* get the values back */
static Boolean
get_one_value (widget_instance* instance, widget_value* val)
{
  Widget widget = name_to_widget (instance, val->name);
      
  if (widget)
    {
#if defined (USE_LUCID)
      if (lw_lucid_widget_p (instance->widget))
	xlw_update_one_value (instance, widget, val);
#endif
#if defined (USE_MOTIF)
      if (lw_motif_widget_p (instance->widget))
	xm_update_one_value (instance, widget, val);
#endif
#if defined (USE_OLIT)
      if (lw_olit_widget_p (instance->widget))
	xol_update_one_value (instance, widget, val);
#endif
      return True;
    }
  else
    return False;
}

Boolean
lw_get_some_values (LWLIB_ID id, widget_value* val_out)
{
  widget_info* info = get_widget_info (id, False);
  widget_instance* instance;
  widget_value* val;
  Boolean result = False;

  if (!info)
    return False;

  instance = info->instances;
  if (!instance)
    return False;

  for (val = val_out; val; val = val->next)
    if (get_one_value (instance, val))
      result = True;

  return result;
}

widget_value*
lw_get_all_values (LWLIB_ID id)
{
  widget_info* info = get_widget_info (id, False);
  widget_value* val = info->val;
  if (lw_get_some_values (id, val))
    return val;
  else
    return NULL;
}

/* internal function used by the library dependent implementation to get the
   widget_value for a given widget in an instance */
widget_value*
lw_get_widget_value_for_widget (widget_instance* instance, Widget w)
{
  char* name = XtName (w);
  widget_value* cur;
  for (cur = instance->info->val; cur; cur = cur->next)
    if (!strcmp (cur->name, name))
      return cur;
  return NULL;
}

/* update other instances value when one thing changed */
/* This function can be used as a an XtCallback for the widgets that get 
  modified to update other instances of the widgets.  Closure should be the
  widget_instance. */
void
lw_internal_update_other_instances (Widget widget, XtPointer closure,
				    XtPointer call_data)
{
  /* To forbid recursive calls */
  static Boolean updating;
  
  widget_instance* instance = (widget_instance*)closure;
  char* name = XtName (widget);
  widget_info* info;
  widget_instance* cur;
  widget_value* val;

  /* never recurse as this could cause infinite recursions. */
  if (updating)
    return;

  /* protect against the widget being destroyed */
  if (XtWidgetBeingDestroyedP (widget))
    return;

  /* Return immediately if there are no other instances */
  info = instance->info;
  if (!info->instances->next)
    return;

  updating = True;

  for (val = info->val; val && strcmp (val->name, name); val = val->next);

  if (val && get_one_value (instance, val))
    for (cur = info->instances; cur; cur = cur->next)
      if (cur != instance)
	set_one_value (cur, val, True);

  updating = False;
}


/* get the id */

LWLIB_ID
lw_get_widget_id (Widget w)
{
  widget_instance* instance = get_widget_instance (w, False);

  return instance ? instance->info->id : 0;
}

/* set the keyboard focus */
void
lw_set_keyboard_focus (Widget parent, Widget w)
{
#if defined (USE_MOTIF)
  xm_set_keyboard_focus (parent, w);
#else
  XtSetKeyboardFocus (parent, w);
#endif
}

/* Show busy */
static void
show_one_widget_busy (Widget w, Boolean flag)
{
  Pixel foreground = 0;
  Pixel background = 1;
  Widget widget_to_invert = XtNameToWidget (w, "*sheet");
  if (!widget_to_invert)
    widget_to_invert = w;
  
  XtVaGetValues (widget_to_invert,
		 XtNforeground, &foreground,
		 XtNbackground, &background,
		 0);
  XtVaSetValues (widget_to_invert,
		 XtNforeground, background,
		 XtNbackground, foreground,
		 0);
}

void
lw_show_busy (Widget w, Boolean busy)
{
  widget_instance* instance = get_widget_instance (w, False);
  widget_info* info;
  widget_instance* next;

  if (instance)
    {
      info = instance->info;
      if (info->busy != busy)
	{
	  for (next = info->instances; next; next = next->next)
	    if (next->widget)
	      show_one_widget_busy (next->widget, busy);
	  info->busy = busy;
	}
    }
}