relationship.h

//
// Copyright 2016 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_USD_RELATIONSHIP_H
#define PXR_USD_USD_RELATIONSHIP_H
 
#include "pxr/pxr.h"
#include "pxr/usd/usd/api.h"
#include "pxr/usd/usd/common.h"
#include "pxr/usd/usd/property.h"
 
#include "pxr/usd/sdf/path.h"
#include "pxr/base/vt/value.h"
 
#include <string>
#include <vector>
 
PXR_NAMESPACE_OPEN_SCOPE
 
 
class UsdRelationship;
 
typedef std::vector<UsdRelationship> UsdRelationshipVector;
 
class UsdRelationship : public UsdProperty {
public:
    UsdRelationship() : UsdProperty(_Null<UsdRelationship>()) {}
 
 
    // XXX Should the mutation API be changed to take UsdObject
    // pointers so that we can enforce (as does Mf) that you can only
    // target extant scenegraph objects? (Note the API would still need to
    // validate those objects since it is easy to create a UsdAttribute
    // or UsdRelationship object not backed by scene description).
 
    USD_API
    bool AddTarget(const SdfPath& target,
           UsdListPosition position=UsdListPositionBackOfPrependList) const;
 
    USD_API
    bool RemoveTarget(const SdfPath& target) const;
 
    USD_API
    bool SetTargets(const SdfPathVector& targets) const;
 
    USD_API
    bool ClearTargets(bool removeSpec) const;
 
    USD_API
    bool GetTargets(SdfPathVector* targets) const;
 
    USD_API
    bool GetForwardedTargets(SdfPathVector* targets) const;
 
    USD_API
    bool HasAuthoredTargets() const;
 
 
private:
    friend class UsdObject;
    friend class UsdPrim;
    friend class Usd_PrimData;
    template <class A0, class A1>
    friend struct UsdPrim_TargetFinder;
 
    UsdRelationship(const Usd_PrimDataHandle &prim,
                    const SdfPath &proxyPrimPath,
                    const TfToken& relName)
        : UsdProperty(UsdTypeRelationship, prim, proxyPrimPath, relName) {}
 
    UsdRelationship(UsdObjType objType,
                    const Usd_PrimDataHandle &prim,
                    const SdfPath &proxyPrimPath,
                    const TfToken &propName)
        : UsdProperty(objType, prim, proxyPrimPath, propName) {}
 
    SdfRelationshipSpecHandle _CreateSpec(bool fallbackCustom=true) const;
    bool _Create(bool fallbackCustom) const;
 
    bool _GetForwardedTargets(SdfPathVector* targets,
                              bool includeForwardingRels) const;
 
    bool _GetForwardedTargetsImpl(SdfPathSet* visited, 
                                  SdfPathSet* uniqueTargets,
                                  SdfPathVector* targets,
                                  bool *foundAnyErrors,
                                  bool includeForwardingRels) const;
 
    SdfPath _GetTargetForAuthoring(const SdfPath &targetPath,
                                   std::string* whyNot = 0) const;
};
 
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif //PXR_USD_USD_RELATIONSHIP_H