Fix #818. (issue2128043)

[n . puttock]

Reviewers: ,

Message:
Hi everybody,

This patch appears to fix the bus error/segfault reported in issue 818,
but it's unclear to me why it works.

Please review.

Thanks,
Neil

Description:
Fix #818.

Use unsmob_engraver ()/unsmob_performer () instead of
explicit casting in translator-group.cc when filtering
translators added via \with { }

* lily/include/performer.hh, lily/performer.hh

  add unsmob_performer ()

* lily/translator-group.cc (filter_engravers/filter_performers):

  use unsmob_* () instead of dynamic_cast when checking
  translator is of correct class to remove

Please review this at http://codereview.appspot.com/2128043/

Affected files:
  M lily/include/performer.hh
  M lily/performer.cc
  M lily/translator-group.cc


Index: lily/include/performer.hh
diff --git a/lily/include/performer.hh b/lily/include/performer.hh
index  
11a5c32c8a59bdf4976d231afcbac05b49cc288e..0b0497e322b2fdacf9ab32fe09fde3bc7842f98a  
100644
--- a/lily/include/performer.hh
+++ b/lily/include/performer.hh
@@ -40,5 +40,7 @@ protected:
   virtual void create_audio_elements ();
 };

+Performer *unsmob_performer (SCM perf);
+
 #endif /* PERFORMER_HH */

Index: lily/performer.cc
diff --git a/lily/performer.cc b/lily/performer.cc
index  
c177f9e975e2760df30700a2470095ccc00c8313..60a0519d42b31336abaa8b1bff32022a46305581  
100644
--- a/lily/performer.cc
+++ b/lily/performer.cc
@@ -19,6 +19,7 @@
 */

 #include "context.hh"
+#include "performer.hh"
 #include "performer-group.hh"
 #include "warn.hh"

@@ -48,3 +49,9 @@ Performer::announce_element (Audio_element_info i)

   get_daddy_performer ()->announce_element (i);
 }
+
+Performer *
+unsmob_performer (SCM perf)
+{
+  return dynamic_cast<Performer *> (unsmob_translator (perf));
+}
Index: lily/translator-group.cc
diff --git a/lily/translator-group.cc b/lily/translator-group.cc
index  
84a97bf52e206bdf980ab6bae228fabac470cbab..6093e4780f8c951a33bb3c148971f2cc546948c4  
100644
--- a/lily/translator-group.cc
+++ b/lily/translator-group.cc
@@ -23,11 +23,13 @@
 #include "context-def.hh"
 #include "context.hh"
 #include "dispatcher.hh"
+#include "engraver.hh"
 #include "engraver-group.hh"
 #include "international.hh"
 #include "main.hh"
 #include "music.hh"
 #include "output-def.hh"
+#include "performer.hh"
 #include "performer-group.hh"
 #include "scheme-engraver.hh"
 #include "scm-hash.hh"
@@ -90,7 +92,7 @@ filter_performers (SCM ell)
   SCM *tail = &ell;
   for (SCM p = ell; scm_is_pair (p); p = scm_cdr (p))
     {
-      if (dynamic_cast<Performer *> (unsmob_translator (scm_car (*tail))))
+      if (unsmob_performer (scm_car (*tail)))
        *tail = scm_cdr (*tail);
       else
        tail = SCM_CDRLOC (*tail);
@@ -104,7 +106,7 @@ filter_engravers (SCM ell)
   SCM *tail = &ell;
   for (SCM p = ell; scm_is_pair (p); p = scm_cdr (p))
     {
-      if (dynamic_cast<Engraver *> (unsmob_translator (scm_car (*tail))))
+      if (unsmob_engraver (scm_car (*tail)))
        *tail = scm_cdr (*tail);
       else
        tail = SCM_CDRLOC (*tail);