git-svn-id: svn://localhost/ardour2/branches/3.0@3437 d708f5d6-7413-0410-9779-e7cbd77b26cf
175 lines
5.6 KiB
C++
175 lines
5.6 KiB
C++
// -*- c++ -*-
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/*
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* Copyright 2002, The libsigc++ Development Team
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#ifndef _SIGC_VISIT_EACH_HPP_
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#define _SIGC_VISIT_EACH_HPP_
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#include <sigc++/type_traits.h>
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namespace sigc {
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namespace internal {
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//This should really be an inner class of limit_derived_target, without the T_limit template type,
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//But the SUN CC 5.7 (not earlier versions) compiler finds it ambiguous when we specify a particular specialization of it.
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//and does not seem to allow us to tell it explicitly that it's an inner class.
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template <bool I_derived, class T_type, class T_limit>
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struct with_type;
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//Specialization for I_derived = false
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template <class T_type, class T_limit> struct
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with_type<false, T_type, T_limit>
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{
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static void execute_(const T_type&, const T_limit&) {}
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};
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//Specialization for I_derived = true
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template <class T_type, class T_limit>
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struct with_type<true, T_type, T_limit>
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{
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static void execute_(const T_type& _A_type, const T_limit& _A_action)
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{ _A_action.action_(_A_type); }
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};
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/// Helper struct for visit_each_type().
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template <class T_target, class T_action>
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struct limit_derived_target
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{
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typedef limit_derived_target<T_target, T_action> T_self;
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template <class T_type>
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void operator()(const T_type& _A_type) const
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{
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with_type<is_base_and_derived<T_target, T_type>::value, T_type, T_self>::execute_(_A_type, *this);
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}
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limit_derived_target(const T_action& _A_action)
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: action_(_A_action)
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{}
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T_action action_;
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};
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// Specialization for T_target pointer types, to provide a slightly different execute_() implementation.
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template <bool I_derived, class T_type, class T_limit>
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struct with_type_pointer;
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//Specialization for I_derived = false
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template <class T_type, class T_limit>
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struct with_type_pointer<false, T_type, T_limit>
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{
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static void execute_(const T_type&, const T_limit&) {}
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};
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//Specialization for I_derived = true
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template <class T_type, class T_limit>
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struct with_type_pointer<true, T_type, T_limit>
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{
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static void execute_(const T_type& _A_type, const T_limit& _A_action)
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{ _A_action.action_(&_A_type); }
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};
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template <class T_target, class T_action>
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struct limit_derived_target<T_target*, T_action>
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{
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typedef limit_derived_target<T_target*, T_action> T_self;
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template <class T_type>
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void operator()(const T_type& _A_type) const
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{
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with_type_pointer<is_base_and_derived<T_target, T_type>::value, T_type, T_self>::execute_(_A_type, *this);
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}
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limit_derived_target(const T_action& _A_action)
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: action_(_A_action)
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{}
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T_action action_;
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};
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} /* namespace internal */
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/** This function performs a functor on each of the targets of a functor.
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* All unknown types just call @e _A_action on them.
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* Add overloads that specialize the @e T_functor argument for your own
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* functor types, so that subobjects get visited. This is needed to enable
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* auto-disconnection support for your functor types.
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*
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* @par Example:
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* @code
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* struct some_functor
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* {
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* void operator()() {}
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* some_possibly_sigc_trackable_derived_type some_data_member;
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* some_other_functor_type some_other_functor;
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* }
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*
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* namespace sigc
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* {
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* template <class T_action>
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* void visit_each(const T_action& _A_action,
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* const some_functor& _A_target)
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* {
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* visit_each(_A_action, _A_target.some_data_member);
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* visit_each(_A_action, _A_target.some_other_functor);
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* }
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* }
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* @endcode
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*
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* @ingroup functors
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*/
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template <class T_action, class T_functor>
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void visit_each(const T_action& _A_action, const T_functor& _A_functor)
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{ _A_action(_A_functor); }
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/** This function performs a functor on each of the targets
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* of a functor limited to a restricted type.
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*
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* @ingroup functors
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*/
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template <class T_type, class T_action, class T_functor>
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void visit_each_type(const T_action& _A_action, const T_functor& _A_functor)
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{
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typedef internal::limit_derived_target<T_type, T_action> type_limited_action;
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type_limited_action limited_action(_A_action);
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//specifying the types of the template specialization prevents disconnection of bound trackable references (such as with sigc::ref()),
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//probably because the visit_each<> specializations take various different template types,
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//in various sequences, and we are probably specifying only a subset of them with this.
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//
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//But this is required by the AIX (and maybe IRIX MipsPro and Tru64) compilers.
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//I guess that sigc::ref() therefore does not work on those platforms. murrayc
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//visit_each<type_limited_action, T_functor>(limited_action, _A_functor);
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//g++ (even slightly old ones) is our primary platform, so we could use the non-crashing version.
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//However, the expliict version also fixes a crash in a slightl more common case: http://bugzilla.gnome.org/show_bug.cgi?id=169225
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//Users (and distributors) of libsigc++ on AIX (and maybe IRIX MipsPro and Tru64) do
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//need to use the version above instead, to allow compilation.
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visit_each(limited_action, _A_functor);
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}
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} /* namespace sigc */
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#endif
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