llvm/llvm/include/llvm/ADT/ImmutableMap.h

//===--- ImmutableMap.h - Immutable (functional) map interface --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// This file defines the ImmutableMap class.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_ADT_IMMUTABLEMAP_H
#define LLVM_ADT_IMMUTABLEMAP_H

#include "llvm/ADT/FoldingSet.h"
#include "llvm/ADT/ImmutableSet.h"
#include "llvm/Support/Allocator.h"
#include <utility>

namespace llvm {

/// ImutKeyValueInfo -Traits class used by ImmutableMap.  While both the first
/// and second elements in a pair are used to generate profile information,
/// only the first element (the key) is used by isEqual and isLess.
template <typename T, typename S>
struct ImutKeyValueInfo { … };

template <typename KeyT, typename ValT,
          typename ValInfo = ImutKeyValueInfo<KeyT,ValT>>
class ImmutableMap {
public:
  using value_type = typename ValInfo::value_type;
  using value_type_ref = typename ValInfo::value_type_ref;
  using key_type = typename ValInfo::key_type;
  using key_type_ref = typename ValInfo::key_type_ref;
  using data_type = typename ValInfo::data_type;
  using data_type_ref = typename ValInfo::data_type_ref;
  using TreeTy = ImutAVLTree<ValInfo>;

protected:
  IntrusiveRefCntPtr<TreeTy> Root;

public:
  /// Constructs a map from a pointer to a tree root.  In general one
  /// should use a Factory object to create maps instead of directly
  /// invoking the constructor, but there are cases where make this
  /// constructor public is useful.
  explicit ImmutableMap(const TreeTy *R) : … { … }

  class Factory {
    typename TreeTy::Factory F;
    const bool Canonicalize;

  public:
    Factory(bool canonicalize = true) : Canonicalize(canonicalize) {}

    Factory(BumpPtrAllocator &Alloc, bool canonicalize = true)
        : F(Alloc), Canonicalize(canonicalize) {}

    Factory(const Factory &) = delete;
    Factory &operator=(const Factory &) = delete;

    ImmutableMap getEmptyMap() { return ImmutableMap(F.getEmptyTree()); }

    [[nodiscard]] ImmutableMap add(ImmutableMap Old, key_type_ref K,
                                   data_type_ref D) {
      TreeTy *T = F.add(Old.Root.get(), std::pair<key_type, data_type>(K, D));
      return ImmutableMap(Canonicalize ? F.getCanonicalTree(T): T);
    }

    [[nodiscard]] ImmutableMap remove(ImmutableMap Old, key_type_ref K) {
      TreeTy *T = F.remove(Old.Root.get(), K);
      return ImmutableMap(Canonicalize ? F.getCanonicalTree(T): T);
    }

    typename TreeTy::Factory *getTreeFactory() const {
      return const_cast<typename TreeTy::Factory *>(&F);
    }
  };

  bool contains(key_type_ref K) const { … }

  bool operator==(const ImmutableMap &RHS) const { … }

  bool operator!=(const ImmutableMap &RHS) const { … }

  TreeTy *getRoot() const { … }

  TreeTy *getRootWithoutRetain() const { … }

  void manualRetain() { … }

  void manualRelease() { … }

  bool isEmpty() const { … }

public:
  //===--------------------------------------------------===//
  // For testing.
  //===--------------------------------------------------===//

  void verify() const { … }

  //===--------------------------------------------------===//
  // Iterators.
  //===--------------------------------------------------===//

  class iterator : public ImutAVLValueIterator<ImmutableMap> {
    friend class ImmutableMap;

    iterator() = default;
    explicit iterator(TreeTy *Tree) : iterator::ImutAVLValueIterator(Tree) {}

  public:
    key_type_ref getKey() const { return (*this)->first; }
    data_type_ref getData() const { return (*this)->second; }
  };

  iterator begin() const { … }
  iterator end() const { … }

  data_type* lookup(key_type_ref K) const { … }

  /// getMaxElement - Returns the <key,value> pair in the ImmutableMap for
  ///  which key is the highest in the ordering of keys in the map.  This
  ///  method returns NULL if the map is empty.
  value_type* getMaxElement() const { … }

  //===--------------------------------------------------===//
  // Utility methods.
  //===--------------------------------------------------===//

  unsigned getHeight() const { … }

  static inline void Profile(FoldingSetNodeID& ID, const ImmutableMap& M) { … }

  inline void Profile(FoldingSetNodeID& ID) const { … }
};

// NOTE: This will possibly become the new implementation of ImmutableMap some day.
template <typename KeyT, typename ValT,
typename ValInfo = ImutKeyValueInfo<KeyT,ValT>>
class ImmutableMapRef {
public:
  using value_type = typename ValInfo::value_type;
  using value_type_ref = typename ValInfo::value_type_ref;
  using key_type = typename ValInfo::key_type;
  using key_type_ref = typename ValInfo::key_type_ref;
  using data_type = typename ValInfo::data_type;
  using data_type_ref = typename ValInfo::data_type_ref;
  using TreeTy = ImutAVLTree<ValInfo>;
  using FactoryTy = typename TreeTy::Factory;

protected:
  IntrusiveRefCntPtr<TreeTy> Root;
  FactoryTy *Factory;

public:
  /// Constructs a map from a pointer to a tree root.  In general one
  /// should use a Factory object to create maps instead of directly
  /// invoking the constructor, but there are cases where make this
  /// constructor public is useful.
  ImmutableMapRef(const TreeTy *R, FactoryTy *F)
      : … { … }

  ImmutableMapRef(const ImmutableMap<KeyT, ValT> &X,
                  typename ImmutableMap<KeyT, ValT>::Factory &F)
      : … { … }

  static inline ImmutableMapRef getEmptyMap(FactoryTy *F) { … }

  void manualRetain() { … }

  void manualRelease() { … }

  ImmutableMapRef add(key_type_ref K, data_type_ref D) const { … }

  ImmutableMapRef remove(key_type_ref K) const { … }

  bool contains(key_type_ref K) const { … }

  ImmutableMap<KeyT, ValT> asImmutableMap() const { … }

  bool operator==(const ImmutableMapRef &RHS) const { … }

  bool operator!=(const ImmutableMapRef &RHS) const { … }

  bool isEmpty() const { … }

  //===--------------------------------------------------===//
  // For testing.
  //===--------------------------------------------------===//

  void verify() const { … }

  //===--------------------------------------------------===//
  // Iterators.
  //===--------------------------------------------------===//

  class iterator : public ImutAVLValueIterator<ImmutableMapRef> {
    friend class ImmutableMapRef;

    iterator() = default;
    explicit iterator(TreeTy *Tree) : iterator::ImutAVLValueIterator(Tree) {}

  public:
    key_type_ref getKey() const { return (*this)->first; }
    data_type_ref getData() const { return (*this)->second; }
  };

  iterator begin() const { … }
  iterator end() const { … }

  data_type *lookup(key_type_ref K) const { … }

  /// getMaxElement - Returns the <key,value> pair in the ImmutableMap for
  ///  which key is the highest in the ordering of keys in the map.  This
  ///  method returns NULL if the map is empty.
  value_type* getMaxElement() const { … }

  //===--------------------------------------------------===//
  // Utility methods.
  //===--------------------------------------------------===//

  unsigned getHeight() const { … }

  static inline void Profile(FoldingSetNodeID &ID, const ImmutableMapRef &M) { … }

  inline void Profile(FoldingSetNodeID &ID) const { … }
};

} // end namespace llvm

#endif // LLVM_ADT_IMMUTABLEMAP_H