Re: Patch: FYI: important memory-trashing fix

[Andrew Haley <aph at redhat dot com>]

Mohan Embar writes:
 > 
 > P.S. With my handy-dandy macro, here is an example of how
 > gnu::awt::gtk::GtkButtonPeer::setLabel can be rewritten.
 > (I'm typing this off the top of my head, so there may be
 > slight errors):
 > 
 > Current CVS Version:
 > 
 > void
 > gnu::awt::gtk::GtkButtonPeer::setLabel (java::lang::String *label)
 > {
 >   _Jv_GdkThreadLock sync;
 >   jsize len = 0;
 >   if (label)
 >     len = JvGetStringUTFLength (label);
 >   char buf[len + 1];
 >   // FIXME: this can allocate an unbounded amount.  Should use heap
 >   // even though it is slower.
 >   if (label)
 >     JvGetStringUTFRegion (label, 0, label->length(), buf);
 >   buf[len] = '\0';
 >   // The button child is a label.
 >   GtkBin *bin = GTK_BIN (ptr);
 >   gtk_label_set_text (GTK_LABEL (bin->child), buf);
 > }
 > 
 > Rewritten version:
 > 
 > static const char*
 > safe_cstr(const char* buf)
 > {
 >   return buf ? buf : "";
 > }
 > 
 > void
 > gnu::awt::gtk::GtkButtonPeer::setLabel (java::lang::String *label)
 > {
 >   _Jv_GdkThreadLock sync;
 >   JV_TEMP_UTF_STRING(utflabel, label);
 > 
 >   // The button child is a label.
 >   GtkBin *bin = GTK_BIN (ptr);
 >   gtk_label_set_text (GTK_LABEL (bin->child), safe_cstr (utflabel));
 > }

Why would you want to use a macro?  Surely you could do

 void
 gnu::awt::gtk::GtkButtonPeer::setLabel (java::lang::String *label)
 {
   _Jv_GdkThreadLock sync;
   Jv_temp_utf_string utflabel(label);
 
   // The button child is a label.
   GtkBin *bin = GTK_BIN (ptr);
   gtk_label_set_text (GTK_LABEL (bin->child), safe_cstr (utflabel.data));
 }

or somesuch.

Andrew.