src/tint/lang/wgsl/ast/transform/substitute_override.h

// Copyright 2022 The Tint Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
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//
//     http://www.apache.org/licenses/LICENSE-2.0
//
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// distributed under the License is distributed on an "AS IS" BASIS,
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#ifndef SRC_TINT_LANG_WGSL_AST_TRANSFORM_SUBSTITUTE_OVERRIDE_H_
#define SRC_TINT_LANG_WGSL_AST_TRANSFORM_SUBSTITUTE_OVERRIDE_H_

#include <string>
#include <unordered_map>

#include "tint/override_id.h"

#include "src/tint/lang/wgsl/ast/transform/transform.h"
#include "src/tint/utils/reflection/reflection.h"

namespace tint::ast::transform {

/// A transform that replaces overrides with the constant values provided.
///
/// # Example
/// ```
/// override width: f32;
/// @id(1) override height: i32 = 4;
/// override depth = 1i;
/// ```
///
/// When transformed with `width` -> 1, `1` -> 22, `depth` -> 42
///
/// ```
/// const width: f32 = 1f;
/// const height: i32 = 22i;
/// const depth = 42i;
/// ```
///
/// @see crbug.com/tint/1582
class SubstituteOverride final : public Castable<SubstituteOverride, Transform> {
  public:
    /// Configuration options for the transform
    struct Config final : public Castable<Config, Data> {
        /// Constructor
        Config();

        /// Copy constructor
        Config(const Config&);

        /// Destructor
        ~Config() override;

        /// Assignment operator
        /// @returns this Config
        Config& operator=(const Config&);

        /// The map of override identifier to the override value.
        /// The value is always a double coming into the transform and will be
        /// converted to the correct type through and initializer.
        std::unordered_map<OverrideId, double> map;

        /// Reflect the fields of this class so that it can be used by tint::ForeachField()
        TINT_REFLECT(map);
    };

    /// Constructor
    SubstituteOverride();

    /// Destructor
    ~SubstituteOverride() override;

    /// @copydoc Transform::Apply
    ApplyResult Apply(const Program* program,
                      const DataMap& inputs,
                      DataMap& outputs) const override;
};

}  // namespace tint::ast::transform

#endif  // SRC_TINT_LANG_WGSL_AST_TRANSFORM_SUBSTITUTE_OVERRIDE_H_