src/dawn/native/ResourceTableDefaultResources.h

// Copyright 2026 The Dawn & Tint Authors
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#ifndef SRC_DAWN_NATIVE_RESOURCETABLEDEFAULTRESOURCES_H_
#define SRC_DAWN_NATIVE_RESOURCETABLEDEFAULTRESOURCES_H_

#include <variant>

#include "dawn/common/NonMovable.h"
#include "dawn/common/Ref.h"
#include "dawn/common/ityp_span.h"
#include "dawn/common/ityp_vector.h"
#include "dawn/native/IntegerTypes.h"
#include "dawn/native/Sampler.h"

namespace tint {
enum class ResourceType : uint32_t;
}  // namespace tint

namespace dawn::native {

// Used to cache the default resources on the device so they can be reused between resource tables.
class ResourceTableDefaultResources : public NonMovable {
  public:
    using Resource = std::variant<Ref<TextureViewBase>, Ref<SamplerBase>>;

    // Returns the order in which we will put the default bindings at the end of the resource table
    // TODO(https://issues.chromium.org/463925499): Take the device in parameter to know if we have
    // sampling vs. full resource table.
    static ityp::span<ResourceTableSlot, const tint::ResourceType> GetOrder();

    // Returns the total number of default bindings
    static ResourceTableSlot GetCount();

    // Returns the index of `resourceType` in the span returned by `GetOrder()`
    static ResourceTableSlot IndexOf(tint::ResourceType resourceType);

    // Lazily creates and returns the default resources
    ResultOrError<ityp::span<ResourceTableSlot, Resource>> GetOrCreate(DeviceBase* device);

  private:
    ityp::vector<ResourceTableSlot, Resource> mDefaultResources;
};

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_RESOURCETABLEDEFAULTRESOURCES_H_