LUMIERA.clone/src/proc/mobject/session/scope.hpp
Ichthyostega 8e16149a25 Ticket #155: rename Track -> Fork (II)
actual renaming of types and variables in the entire code base
2015-05-31 02:03:24 +02:00

121 lines
4 KiB
C++

/*
SCOPE.hpp - nested search scope for properties of placement
Copyright (C) Lumiera.org
2009, Hermann Vosseler <Ichthyostega@web.de>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef PROC_MOBJECT_SESSION_SCOPE_H
#define PROC_MOBJECT_SESSION_SCOPE_H
#include "proc/mobject/placement.hpp"
#include "proc/mobject/placement-ref.hpp"
#include "lib/error.hpp"
#include <string>
namespace proc {
namespace mobject {
namespace session {
LUMIERA_ERROR_DECLARE (NO_PARENT_SCOPE); ///< Parent scope of root not accessible
LUMIERA_ERROR_DECLARE (INVALID_SCOPE); ///< Placement scope invalid and not locatable within model
/**
* A Placement scope within the high-level-model.
* Within the Session/Model, Placements are used to attach
* MObjects; but beyond that, each Placement can \em contain
* other Placements, effectively forming a scope. Thus Scope
* is basically another view on Placements <i>which are attached
* to the session.</i> This (hidden) link to the session is utilised
* to establish the nesting of scopes and allow querying and navigating.
*
* Actually, Scope is implemented through a PlacementRef pointing to
* the Placement which \em constitutes this Scope. We call this Placement
* the "scope top". A fork e.g. can \em contain several clips, but also
* nested sub forks, all of which would be within the scope of this fork.
* This scoping relation plays an important role when it comes to \em resolving
* properties of placement, like e.g. the output designation, overlay mode,
* sound pan position etc -- properties from enclosing scopes will be
* inherited unless \em shaded by local definitions, similar to the
* behaviour known from most programming languages when referring
* to local variables.
* @note Scope is a passive entity,
* basically just wrapping up a Scope-top Placement.
* Contrast this to QueryFocus, which actively
* maintains the current focus location
* and exposes query facilities.
*/
class Scope
{
RefPlacement anchor_;
public:
Scope (PlacementMO const& constitutingPlacement);
Scope (); ///< unlocated NIL scope
explicit
Scope (PlacementMO::ID const& constitutingPlacement);
Scope (Scope const&);
Scope& operator= (Scope const&);
static const Scope INVALID;
static Scope containing (PlacementMO const& aPlacement);
static Scope containing (RefPlacement const& refPlacement);
operator std::string() const;
Scope getParent() const;
PlacementMO& getTop() const;
bool isValid() const;
bool isRoot() const;
friend bool operator== (Scope const&, Scope const&);
friend bool operator!= (Scope const&, Scope const&);
};
/** as scopes are constituted by a "scope top" element (placement)
* registered within the PlacementIndex of the current session,
* equality is defined in terms of this defining placement.
*/
inline bool
operator== (Scope const& scope1, Scope const& scope2)
{
return scope1.anchor_ == scope2.anchor_;
}
inline bool
operator!= (Scope const& scope1, Scope const& scope2)
{
return scope1.anchor_ != scope2.anchor_;
}
}}} // namespace proc::mobject::session
#endif