//===--- AvailabilityContextStorage.h - Swift AvailabilityContext ---------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
//
// This file defines types used in the implementation of AvailabilityContext.
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_AST_AVAILABILITY_CONTEXT_STORAGE_H
#define SWIFT_AST_AVAILABILITY_CONTEXT_STORAGE_H

#include "swift/AST/AvailabilityContext.h"
#include "llvm/ADT/FoldingSet.h"
#include "llvm/Support/TrailingObjects.h"

namespace swift {

class DeclAvailabilityConstraints;

/// A wrapper for storing an `AvailabilityDomain` and its associated information
/// in `AvailabilityContext::Storage`.
class AvailabilityContext::DomainInfo final {
  AvailabilityDomain domain;
  AvailabilityRange range;

public:
  DomainInfo(AvailabilityDomain domain, const AvailabilityRange &range)
      : domain(domain), range(range) {};

  static DomainInfo unavailable(AvailabilityDomain domain) {
    return DomainInfo(domain, AvailabilityRange::neverAvailable());
  }

  AvailabilityDomain getDomain() const { return domain; }
  AvailabilityRange getRange() const { return range; }
  bool isUnavailable() const { return range.isKnownUnreachable(); }

  bool constrainRange(const AvailabilityRange &range);

  void Profile(llvm::FoldingSetNodeID &ID) const {
    ID.AddPointer(domain.getOpaqueValue());
    range.getRawVersionRange().Profile(ID);
  }
};

/// As an implementation detail, the values that make up an `Availability`
/// context are uniqued and stored as folding set nodes.
class AvailabilityContext::Storage final
    : public llvm::FoldingSetNode,
      public llvm::TrailingObjects<Storage, DomainInfo> {
  friend TrailingObjects;

  Storage(const AvailabilityRange &platformRange, bool isDeprecated,
          unsigned domainInfoCount)
      : platformRange(platformRange), isDeprecated(isDeprecated),
        domainInfoCount(domainInfoCount) {};

public:
  /// The introduction version for the current platform.
  const AvailabilityRange platformRange;

  /// Whether or not the context is considered deprecated on the current
  /// platform.
  const unsigned isDeprecated : 1;

  /// The number of `DomainInfo` objects in trailing storage.
  const unsigned domainInfoCount;

  /// Retrieves the unique storage instance from the `ASTContext` for the given
  /// parameters.
  static const Storage *get(const AvailabilityRange &platformRange,
                            bool isDeprecated,
                            llvm::ArrayRef<DomainInfo> domainInfos,
                            const ASTContext &ctx);

  llvm::ArrayRef<DomainInfo> getDomainInfos() const {
    return llvm::ArrayRef(getTrailingObjects<DomainInfo>(), domainInfoCount);
  }

  llvm::SmallVector<DomainInfo, 4> copyDomainInfos() const {
    return llvm::SmallVector<DomainInfo, 4>{getDomainInfos()};
  }

  /// Uniquing for `ASTContext`.
  static void Profile(llvm::FoldingSetNodeID &ID,
                      const AvailabilityRange &platformRange, bool isDeprecated,
                      llvm::ArrayRef<DomainInfo> domainInfos);

  void Profile(llvm::FoldingSetNodeID &ID) const {
    Profile(ID, platformRange, static_cast<bool>(isDeprecated),
            getDomainInfos());
  }
};

} // end namespace swift

#endif