resolveTarget.h

//
// Copyright 2022 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_USD_RESOLVE_TARGET_H
#define PXR_USD_USD_RESOLVE_TARGET_H
 
#include "pxr/pxr.h"
#include "pxr/usd/usd/api.h"
#include "pxr/usd/pcp/node.h"
#include "pxr/usd/pcp/primIndex.h"
#include "pxr/usd/sdf/declareHandles.h"
 
#include <memory>
 
PXR_NAMESPACE_OPEN_SCOPE
 
SDF_DECLARE_HANDLES(SdfLayer);
 
class UsdResolveTarget {
 
public:
    UsdResolveTarget() = default;
 
    const PcpPrimIndex *GetPrimIndex() const {
        return _expandedPrimIndex.get();
    }
 
    USD_API
    PcpNodeRef GetStartNode() const;
 
    USD_API
    SdfLayerHandle GetStartLayer() const;
 
    USD_API
    PcpNodeRef GetStopNode() const;
 
    USD_API
    SdfLayerHandle GetStopLayer() const;
 
    bool IsNull() const {
        return !bool(_expandedPrimIndex);
    }
 
private:
    // Non-null UsdResolveTargets can only be created by functions in UsdPrim 
    // and UsdPrimCompositionQueryArc.
    friend class UsdPrim;
    friend class UsdPrimCompositionQueryArc;
 
    // Usd_Resolver wants to access the iterators provided by this target.
    friend class Usd_Resolver;
 
    USD_API
    UsdResolveTarget(
        const std::shared_ptr<PcpPrimIndex> &index, 
        const PcpNodeRef &node, 
        const SdfLayerHandle &layer);
 
    USD_API
    UsdResolveTarget(
        const std::shared_ptr<PcpPrimIndex> &index, 
        const PcpNodeRef &node, 
        const SdfLayerHandle &layer,
        const PcpNodeRef &stopNode, 
        const SdfLayerHandle &stopLayer);
 
    // Resolve targets are created with an expanded prim index either from
    // a composition query (which owns and holds it) or from a UsdPrim (which
    // creates it solely to create the resolve target). The expanded prim index
    // is not otherwise cached, so we have to hold on to it during the lifetime
    // of the resolve target.
    std::shared_ptr<PcpPrimIndex> _expandedPrimIndex;
    PcpNodeRange _nodeRange;
 
    PcpNodeIterator _startNodeIt;
    SdfLayerRefPtrVector::const_iterator _startLayerIt;
    PcpNodeIterator _stopNodeIt;
    SdfLayerRefPtrVector::const_iterator _stopLayerIt;
};
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif // PXR_USD_USD_RESOLVE_TARGET_H