/*
This file is part of LilyPond, the GNU music typesetter.
- Copyright (C) 1998--2012 Han-Wen Nienhuys <hanwen@xs4all.nl>
+ Copyright (C) 1998--2015 Han-Wen Nienhuys <hanwen@xs4all.nl>
LilyPond is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
#include "protected-scm.hh"
+// We store the data in the car of a cons cell: it is faster to keep
+// only one object protected during the life time of Protected_scm
+// than several.
+
Protected_scm::Protected_scm ()
+ : object_ (SCM_UNDEFINED)
{
- object_ = SCM_UNDEFINED;
}
Protected_scm::Protected_scm (SCM s)
+ : object_ (s)
{
- object_ = SCM_NIMP (s) ? scm_gc_protect_object (s) : s;
+ // Only allow immediate objects at construction time. Protected_scm
+ // is intended for variables of static duration, and creating
+ // non-immediate objects when GUILE is not yet up is a bad idea.
+ assert (SCM_IMP (s));
}
-Protected_scm::Protected_scm (Protected_scm const &s)
-{
- object_ = (SCM_NIMP (s.object_) ? scm_gc_protect_object (s.object_)
- : s.object_);
-}
+SCM Protected_scm::list_ = SCM_EOL;
+SCM Protected_scm::last_ = SCM_EOL;
-Protected_scm::~Protected_scm ()
+void
+Protected_scm::protectify (SCM s)
{
- if (SCM_NIMP (object_))
- scm_gc_unprotect_object (object_);
+ s = scm_list_1 (s);
+ if (SCM_CONSP (last_))
+ SCM_SETCDR (last_, s);
+ else
+ list_ = scm_permanent_object (s);
+ last_ = object_ = s;
}
Protected_scm &
Protected_scm::operator = (SCM s)
{
- if (object_ == s)
- return *this;
+ if (SCM_CONSP (object_))
+ SCM_SETCAR (object_, s);
+ else if (SCM_IMP (s))
+ object_ = s;
+ else
+ protectify (s);
- if (SCM_NIMP (object_))
- scm_gc_unprotect_object (object_);
-
- object_ = SCM_NIMP (s) ? scm_gc_protect_object (s) : s;
return *this;
}
Protected_scm &
Protected_scm::operator = (Protected_scm const &s)
{
- return operator = (s.object_);
+ return *this = (SCM) s;
}
-Protected_scm::operator SCM () const
+Protected_scm::operator SCM const & () const
{
+ if (SCM_CONSP (object_))
+ return *SCM_CARLOC (object_);
return object_;
}
-SCM
-Protected_scm::to_SCM () const
+Protected_scm::operator SCM & ()
{
- return object_;
+ // The reference may be used to overwrite an immediate value with a
+ // non-immediate one, so we _have_ to create full protection.
+ if (!SCM_CONSP (object_))
+ protectify (object_);
+
+ return *SCM_CARLOC (object_);
+}
+
+bool
+Protected_scm::is_bound () const
+{
+ if (SCM_CONSP (object_))
+ return !SCM_UNBNDP (SCM_CAR (object_));
+ return !SCM_UNBNDP (object_);
}