#ifndef THIRD_PARTY_CEL_CPP_EVAL_EVAL_UNKNOWNS_UTILITY_H_

#define THIRD_PARTY_CEL_CPP_EVAL_EVAL_UNKNOWNS_UTILITY_H_

#include <vector>

#include "google/protobuf/arena.h"

#include "absl/types/optional.h"

#include "absl/types/span.h"

#include "eval/eval/attribute_trail.h"

#include "eval/public/activation.h"

#include "eval/public/cel_attribute.h"

#include "eval/public/cel_expression.h"

#include "eval/public/cel_value.h"

#include "eval/public/unknown_attribute_set.h"

#include "eval/public/unknown_set.h"

namespace google {

namespace api {

namespace expr {

namespace runtime {

// Helper class for handling unknowns and missing attribute logic. Provides

// helpers for merging unknown sets from arguments on the stack and for

// identifying unknown/missing attributes based on the patterns for a given

// Evaluation.

class AttributeUtility {

public:

AttributeUtility(

const std::vector<CelAttributePattern>* unknown_patterns,

const std::vector<CelAttributePattern>* missing_attribute_patterns,

google::protobuf::Arena* arena)

: unknown_patterns_(unknown_patterns),

missing_attribute_patterns_(missing_attribute_patterns),

arena_(arena) {}

// Checks whether particular corresponds to any patterns that define missing

// attribute.

bool CheckForMissingAttribute(const AttributeTrail& trail) const;

// Checks whether particular corresponds to any patterns that define unknowns.

bool CheckForUnknown(const AttributeTrail& trail, bool use_partial) const;

// Creates merged UnknownAttributeSet.

// Scans over the args collection, determines if there matches to unknown

// patterns and returns the (possibly empty) collection.

UnknownAttributeSet CheckForUnknowns(absl::Span<const AttributeTrail> args,

bool use_partial) const;

// Creates merged UnknownSet.

// Scans over the args collection, merges any UnknownAttributeSets found in

// it together with initial_set (if initial_set is not null).

// Returns pointer to merged set or nullptr, if there were no sets to merge.

const UnknownSet* MergeUnknowns(absl::Span<const CelValue> args,

const UnknownSet* initial_set) const;

// Creates merged UnknownSet.

// Merges together attributes from UnknownSets found in the args

// collection, attributes from attr that match unknown pattern

// patterns, and attributes from initial_set

// (if initial_set is not null).

// Returns pointer to merged set or nullptr, if there were no sets to merge.

const UnknownSet* MergeUnknowns(absl::Span<const CelValue> args,

absl::Span<const AttributeTrail> attrs,

const UnknownSet* initial_set,

bool use_partial) const;

private:

const std::vector<CelAttributePattern>* unknown_patterns_;

const std::vector<CelAttributePattern>* missing_attribute_patterns_;

google::protobuf::Arena* arena_;

};

} // namespace runtime

} // namespace expr

} // namespace api

} // namespace google

#endif // THIRD_PARTY_CEL_CPP_EVAL_EVAL_UNKNOWNS_UTILITY_H_