sceneIndexPrimView.h

//
// Copyright 2022 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HD_SCENE_INDEX_PRIM_VIEW_H
#define PXR_IMAGING_HD_SCENE_INDEX_PRIM_VIEW_H
 
#include "pxr/pxr.h"
 
#include "pxr/imaging/hd/api.h"
 
#include "pxr/usd/sdf/path.h"
#include "pxr/base/tf/declarePtrs.h"
 
PXR_NAMESPACE_OPEN_SCOPE
 
TF_DECLARE_REF_PTRS(HdSceneIndexBase);
 
class HdSceneIndexPrimView
{
public:
    enum Order
    {
        ChildPrimPaths,
        Lexicographic
    };
 
    class const_iterator
    {
    public:
        inline const SdfPath &operator*() const;
        inline const SdfPath *operator->() const;
 
        HD_API
        const_iterator& operator++();
 
        inline void SkipDescendants();
        inline bool operator==(const const_iterator &other) const;
        inline bool operator!=(const const_iterator &other) const;
 
    private:
        friend class HdSceneIndexPrimView;
        struct _StackFrame;
 
        const_iterator(HdSceneIndexBaseRefPtr const &inputSceneIndex,
                       const SdfPath &root,
                       Order order);
        const_iterator(HdSceneIndexBaseRefPtr const &inputSceneIndex,
                       Order order);
 
        HdSceneIndexBaseRefPtr const _inputSceneIndex;
        std::vector<_StackFrame> _stack;
        bool _skipDescendants;
        Order _order;
    };
 
    HD_API
    HdSceneIndexPrimView(HdSceneIndexBaseRefPtr const &inputSceneIndex,
                         Order order = ChildPrimPaths);
 
    HD_API
    HdSceneIndexPrimView(HdSceneIndexBaseRefPtr const &inputSceneIndex,
                         const SdfPath &root,
                         Order order = ChildPrimPaths);
 
    HD_API
    const const_iterator &begin() const;
 
    HD_API
    const const_iterator &end() const;
 
private:
    const const_iterator _begin;
    const const_iterator _end;
};
 
struct
HdSceneIndexPrimView::const_iterator::_StackFrame
{
    std::vector<SdfPath> paths;
    size_t index;
    
    bool operator==(const _StackFrame &other) const {
        return paths == other.paths && index == other.index;
    }
};
 
const SdfPath &
HdSceneIndexPrimView::const_iterator::operator*() const
{
    const _StackFrame &frame = _stack.back();
    return frame.paths[frame.index];
}
 
const SdfPath *
HdSceneIndexPrimView::const_iterator::operator->() const
{
    return &(**this);
}
 
void
HdSceneIndexPrimView::const_iterator::SkipDescendants()
{
    _skipDescendants = true;
}
 
bool
HdSceneIndexPrimView::const_iterator::operator==(
    const const_iterator &other) const
{
    return _stack == other._stack;
}
 
bool
HdSceneIndexPrimView::const_iterator::operator!=(
    const const_iterator &other) const
{
    return !(*this == other);
}
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif