src/ast/attribute.h

// Copyright 2020 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.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef SRC_AST_ATTRIBUTE_H_
#define SRC_AST_ATTRIBUTE_H_

#include <string>
#include <vector>

#include "src/ast/node.h"

namespace tint {
namespace ast {

/// The base class for all attributes
class Attribute : public Castable<Attribute, Node> {
 public:
  ~Attribute() override;

  /// @returns the WGSL name for the attribute
  virtual std::string Name() const = 0;

 protected:
  /// Constructor
  /// @param pid the identifier of the program that owns this node
  /// @param src the source of this node
  Attribute(ProgramID pid, const Source& src) : Base(pid, src) {}
};

/// A list of attributes
using AttributeList = std::vector<const Attribute*>;

/// @param attributes the list of attributes to search
/// @returns true if `attributes` includes a attribute of type `T`
template <typename T>
bool HasAttribute(const AttributeList& attributes) {
  for (auto* attr : attributes) {
    if (attr->Is<T>()) {
      return true;
    }
  }
  return false;
}

/// @param attributes the list of attributes to search
/// @returns a pointer to `T` from `attributes` if found, otherwise nullptr.
template <typename T>
const T* GetAttribute(const AttributeList& attributes) {
  for (auto* attr : attributes) {
    if (attr->Is<T>()) {
      return attr->As<T>();
    }
  }
  return nullptr;
}

}  // namespace ast
}  // namespace tint

#endif  // SRC_AST_ATTRIBUTE_H_