dataSourceUtils.h

//
// Copyright 2025 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_USD_IMAGING_USD_SKEL_IMAGING_DATA_SOURCE_UTILS_H
#define PXR_USD_IMAGING_USD_SKEL_IMAGING_DATA_SOURCE_UTILS_H
 
#include "pxr/imaging/hd/dataSource.h"
 
PXR_NAMESPACE_OPEN_SCOPE
 
template<typename T>
class UsdSkelImagingSharedPtrThunk
{
public:
    virtual ~UsdSkelImagingSharedPtrThunk() = default;
 
    using Handle = std::shared_ptr<T>;
 
    Handle Get()
    {
        if (auto const result = std::atomic_load(&_data)) {
            return result;
        }
 
        Handle expected;
        Handle desired = _Compute();
 
        if (std::atomic_compare_exchange_strong(&_data, &expected, desired)) {
            return desired;
        } else {
            return expected;
        }
    }
 
    void Invalidate() { std::atomic_store(&_data, Handle()); }
 
protected:
    virtual Handle _Compute() = 0;
 
private:
    Handle _data;
};
 
template<typename T>
auto UsdSkelImagingGetTypedValue(
    const T &ds,
    const HdSampledDataSource::Time shutterOffset = 0.0f)
        -> decltype(ds->GetTypedValue(0.0f))
{
    if (!ds) {
        return {};
    }
    return ds->GetTypedValue(shutterOffset);
}
 
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif