locatorCachingSceneIndex.h

//
// Copyright 2026 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HDSI_LOCATOR_CACHING_SCENE_INDEX
#define PXR_IMAGING_HDSI_LOCATOR_CACHING_SCENE_INDEX
 
#include "pxr/imaging/hd/api.h"
#include "pxr/imaging/hd/filteringSceneIndex.h"
#include "pxr/usd/sdf/pathTable.h"
#include "pxr/base/tf/denseHashMap.h"
#include <mutex>
 
PXR_NAMESPACE_OPEN_SCOPE
 
TF_DECLARE_REF_PTRS(HdsiLocatorCachingSceneIndex);
 
class HdsiLocatorCachingSceneIndex : public HdSingleInputFilteringSceneIndexBase
{
public:
    HD_API
    static HdSceneIndexBaseRefPtr
    AddDependencyForwardingAndCache(
        HdSceneIndexBaseRefPtr const& inputScene,
        HdDataSourceLocator const& locatorToCache,
        TfToken const& primTypeToCache,
        bool const& cacheDescendants = true);
 
    HD_API
    static HdsiLocatorCachingSceneIndexRefPtr
    New(HdSceneIndexBaseRefPtr const& inputScene,
        HdDataSourceLocator const& locatorToCache,
        TfToken const& primTypeToCache,
        bool const& cacheDescendants = true);
 
    HD_API
    ~HdsiLocatorCachingSceneIndex() override;
 
    HD_API 
    HdSceneIndexPrim GetPrim(const SdfPath &primPath) const override;
 
    HD_API 
    SdfPathVector GetChildPrimPaths(const SdfPath &primPath) const override;
 
protected:
    HD_API
    HdsiLocatorCachingSceneIndex(
        HdSceneIndexBaseRefPtr const& inputScene,
        HdDataSourceLocator const& locatorToCache,
        TfToken const& primTypeToCache,
        bool const& cacheDescendants);
 
    void _PrimsAdded(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::AddedPrimEntries &entries) override;
    void _PrimsRemoved(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::RemovedPrimEntries &entries) override;
    void _PrimsDirtied(
        const HdSceneIndexBase &sender,
        const HdSceneIndexObserver::DirtiedPrimEntries &entries) override;
    void _SystemMessage(
        const TfToken& messageType,
        const HdDataSourceBaseHandle& args) override;
 
    // A data source that delegates back to HdsiLocatorCachingSceneIndex, allowing
    // it to manage invalidation.
    class _DataSource : public HdContainerDataSource
    {
    public:
        HD_DECLARE_DATASOURCE(_DataSource);
 
        TfTokenVector GetNames() override;
        HdDataSourceBaseHandle Get(const TfToken &name) override;
 
    private:
        _DataSource(
            HdsiLocatorCachingSceneIndex const* cachingSceneIndex,
            SdfPath const& primPath,
            HdDataSourceLocator const& locator,
            HdContainerDataSourceHandle const& inputDataSource);
 
        const HdsiLocatorCachingSceneIndex& _cachingSceneIndex;
        const SdfPath _primPath;
        const HdDataSourceLocator _locator;
        const HdContainerDataSourceHandle _inputDataSource;
    };
 
    // Retrieve data for the requested locator, populating and
    // re-using cached data sources as appropriate.
    HdDataSourceBaseHandle
    _GetWithCache(
        SdfPath const& primPath,
        HdDataSourceLocator const& locator,
        HdContainerDataSourceHandle const& inputDataSource) const;
 
private: // data
 
    // Cache of data sources within a prim, by locator
    using _LocatorDataSourceMap =
        TfDenseHashMap<HdDataSourceLocator, HdDataSourceBaseHandle, TfHash>;
 
    // Cache of data sources, by prim
    using _PrimCache = SdfPathTable<_LocatorDataSourceMap>;
 
    // Cache strategy parameters.
    const HdDataSourceLocator _locatorToCache;
    const TfToken _primTypeToCache;
    const bool _cacheDescendants;
 
    // Cache contents.
    mutable _PrimCache _primDsCache;
    mutable std::mutex _cacheMutex;
};
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif