[Motiftools-bugs] XmtInputField:SetValues makes incorrect comparisons

[<mot...@li...>]

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                        XMT BUG REPORT FORM
                    ---------------------------

To: mot...@li...
Subject: XmtInputField:SetValues makes incorrect comparisons


YOUR NAME: Fred L. Kleinschmidt
YOUR E-MAIL ADDRESS: fre...@bo...


VERSION OF XMT: 		4.0.0
HARDWARE AND OPERATING SYSTEM: 	(HP-UX_11.0, AIX4.3, IRIX6.5, SunOS5.8)
X LIBRARIES:			X11R6
MOTIF LIBRARY:			Motif 2.1.0
LESSTIF LIBRARY:             =20
COMPILER NAME AND VERSION:	Ansi-C


AREA: XmtInputField
ONE-LINE SUMMARY: SetValue method compares wrong input records.
FULL DESCRIPTION: (Describe the bug or enhancement request below.)
There are three problems in how the XmtInputField SetValues method =
checks for
changes in String resources:
  1. The XmtInputField SetValues method defines:
        #define Changed(field) (rw->input_field.field !=3D =
cw->input_field.field)
      This is incorrect - the Changed macro should compare the new =
widget to the
      current widget, not the requested to the current. It should be:
        #define Changed(field) (sw->input_field.field !=3D =
cw->input_field.field)

  2. String resources should be checked for changes using strcmp(). If =
the
     application calls SetValues on a String resource whose value is =
identical=20
     to the existing value, Changed() will report True when in fact =
there
     was no change, causing unnecessary processing and repaints.

  3. When comparing for changes in string resources, the line
       sw->input_field.xxx =3D XtNewString( sw->input_field.xxx )
     should come BEFORE the XtFree of the current value =
(cw->input_field.xxx).
     By freeing the old value first, there is the possibility that the=20
     XtNewString call will return the same space that was just freed=20
     (This does indeed happen using CYGWIN). When that happens, a =
subsequent
     call to Changed() on the same resource will return False, when in =
truth the
     value did change. This happens for resource "pattern".

    =20

DUPLICATE BY:

     w =3D XtVaCreateManagedWidget( "inputfield", =
xmtInputFieldWidgetClass,
                              parent,
                              XmtNpattern, "dd",
                              NULL);
   /* at this point, the input field will accept at most two digits.*/

   /* if we subsequently make this call: */
       XtVaSetValues( w, XmNpattern, "dddd", NULL);
   /* then it should now accept four; however, it only accepts two.
    * This is becauses SetValues failed to call XmTextSetMaxLength =
because
    * of the above errors.
    *
    * Also, the SetValues call may cause a crash due to separately =
reported bug
    * where Initialize() fails to copy pattern, but SetValues frees it.
    */


WORKAROUND:
[If you've found a temporary workaround for the bug, please describe =
it.]


SUGGESTED FIX:=20

/* ARGSUSED */
#if NeedFunctionPrototypes
static Boolean SetValues(Widget current, Widget request, Widget set,
			 ArgList arglist, Cardinal *num_args)
#else
static Boolean SetValues(current, request, set, arglist, num_args)
Widget current;
Widget request;
Widget set;
ArgList arglist;
Cardinal *num_args;
#endif
{
    XmtInputFieldWidget cw =3D (XmtInputFieldWidget) current;
    XmtInputFieldWidget rw =3D (XmtInputFieldWidget) request;
    XmtInputFieldWidget sw =3D (XmtInputFieldWidget) set;

#define Current(field) (cw->input_field.field)   =20
#define Request(field) (rw->input_field.field)
#define Set(field) (sw->input_field.field)
/* (BOEING flk) Compare sw to cw, not rw to cw */   =20
#define Changed(field) (sw->input_field.field !=3D =
cw->input_field.field)

/* (BOEING flk) Must copy new one before freeing old one.
 * Otherwise, if Changed(x) is performed twice on the same field,
 * it may report false after initially being true, if the new
 * allocation happens to take the same space as the old one.
 *=20
    /*
     * handle changes to the buffer or target symbol names
     */
    if (Changed(buffer_symbol_name)) {
        if (Set(buffer_symbol_name)) {
	        Set(buffer_symbol_name) =3D =
XtNewString(Set(buffer_symbol_name));
	        BindBufferSymbol(sw);
        }
        /* XXX do something with the new value in the symbol? */
        if (Current(buffer_symbol_name)) {
	        XtFree(Current(buffer_symbol_name));
	        ReleaseBufferSymbol(cw);
        }
    }
    if (Changed(target_symbol_name)) {
        if (Set(target_symbol_name)) {
	        Set(target_symbol_name) =3D =
XtNewString(Set(target_symbol_name));
	        BindTargetSymbol(sw);
        }
        if (Current(target_symbol_name)) {
	        XtFree(Current(target_symbol_name));
	        ReleaseTargetSymbol(cw);
        }
    }

    /*
     * if the value resource changes, copy the new value, set it on the
     * text widget, and copy it to the buffer, and target, if any.  Note
     * that we do not call the verifyCallback, nor do we handle errors.
     * Note that changing value updates the buffer, but changing the =
buffer
     * does not change the value.
     */
    if (Changed(input)) {
        XtFree(Current(input));
        if (Set(input)) {
	        Set(input) =3D XtNewString(Set(input));
        }
        SetString(set, Set(input));
        (void)SetValueOnSymbols(sw, Set(input), False);
    }

    if (Changed(overstrike)) {
	if (Set(overstrike))
	    XtAddCallback(set, XmNmodifyVerifyCallback,
			  HandleOverstrike, NULL);
	else
	    XtRemoveCallback(set, XmNmodifyVerifyCallback,
			     HandleOverstrike, NULL);
    }

    /* if pattern changed, free old, copy new, and adjust callbacks */
    if (Changed(pattern)) {
	    /* if the new pattern is NULL, remove the callbacks, else copy */
	    if (Set(pattern) =3D=3D NULL) {
	        XtRemoveCallback(set, XmNmodifyVerifyCallback,HandlePattern, =
NULL);
	    }
	    else
	        Set(pattern) =3D XtNewString(Set(pattern));
	    /* if the old pattern was NULL, add the callbacks, else free */
	    if (Current(pattern) =3D=3D NULL) {
	        XtAddCallback(set, XmNmodifyVerifyCallback, HandlePattern, =
NULL);
	    }
	    else
	        XtFree(Current(pattern));
=09
	    /* get the new size of the pattern */
	    if (Set(pattern))=20
	        Set(pattern_length) =3D strlen(Set(pattern));
	    else
	        Set(pattern_length) =3D 0;
    }

    /*
     * update max_length from pattern or buffer size
     */
    if (sw->text.max_length !=3D Current(max_length))
        Set(max_length) =3D sw->text.max_length;
    else if (Changed(pattern))
        Set(max_length) =3D Set(pattern_length);
    else if (Changed(buffer_symbol) && Set(buffer_symbol))
        Set(max_length) =3D XmtSymbolSize(Set(buffer_symbol));
    /*
     * if max_length  or overstrike changed,=20
     * update the internal widget
     */
    if (Changed(max_length) || Changed(overstrike))
	XmTextSetMaxLength(set, Set(overstrike)?MAXINT:Set(max_length));
   =20
    /*=20
     * if sensitivity changes, set the layoutSensitive resource, in case
     * we're a child of XmtLayout, and have a caption.
     */
    if ((sw->core.sensitive !=3D cw->core.sensitive) ||
	(sw->core.ancestor_sensitive !=3D cw->core.ancestor_sensitive)) {
	XtVaSetValues(set, XmtNlayoutSensitive,
		      sw->core.sensitive && sw->core.ancestor_sensitive, NULL);
    }

    /* never need to redraw */
    return False;

#undef Current
#undef Request
#undef Set	   =20
#undef Changed   =20
}

REPEAT BY:
[What you did to get the error; include test program or session
transcript if at all possible.]



Fred L. Kleinschmidt
Associate Technical Fellow
Technical Architect, Common User Interface Services
e-Business Technology Center
M/S 2R-94  (206)544-5225