Make the fuchsia mojo/public repo the source of truth.

mojo/public/cpp/bindings/map.h

-// Copyright 2014 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#ifndef MOJO_PUBLIC_CPP_BINDINGS_MAP_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_MAP_H_
-
-#include <map>
-#include <type_traits>
-
-#include "mojo/public/cpp/bindings/lib/map_internal.h"
-#include "mojo/public/cpp/bindings/lib/template_util.h"
-
-namespace mojo {
-
-// A move-only map that can handle move-only values. Map has the following
-// characteristics:
-//   - The map itself can be null, and this is distinct from empty.
-//   - Keys must not be move-only.
-//   - The Key-type's "<" operator is used to sort the entries, and also is
-//     used to determine equality of the key values.
-//   - There can only be one entry per unique key.
-//   - Values of move-only types will be moved into the Map when they are added
-//     using the insert() method.
-template <typename Key, typename Value>
-class Map {
- public:
-  // Map keys cannot be move only classes.
-  static_assert(!internal::IsMoveOnlyType<Key>::value,
-                "Map keys cannot be move only types.");
-
-  using KeyType = Key;
-  using ValueType = Value;
-
-  using Traits =
-      internal::MapTraits<KeyType,
-                          ValueType,
-                          internal::IsMoveOnlyType<ValueType>::value>;
-  using ValueForwardType = typename Traits::ValueForwardType;
-
-  using Data_ =
-      internal::Map_Data<typename internal::WrapperTraits<KeyType>::DataType,
-                         typename internal::WrapperTraits<ValueType>::DataType>;
-
-  Map() : is_null_(true) {}
-
-  // Constructs a non-null Map containing the specified |keys| mapped to the
-  // corresponding |values|.
-  Map(mojo::Array<KeyType> keys, mojo::Array<ValueType> values)
-      : is_null_(false) {
-    MOJO_DCHECK(keys.size() == values.size());
-    for (size_t i = 0; i < keys.size(); ++i)
-      Traits::Insert(&map_, keys[i], values[i]);
-  }
-
-  ~Map() {}
-
-  Map(Map&& other) : is_null_(true) { Take(&other); }
-  Map& operator=(Map&& other) {
-    Take(&other);
-    return *this;
-  }
-
-  // Copies the contents of some other type of map into a new Map using a
-  // TypeConverter. A TypeConverter for std::map to Map is defined below.
-  template <typename U>
-  static Map From(const U& other) {
-    return TypeConverter<Map, U>::Convert(other);
-  }
-
-  // Copies the contents of the Map into some other type of map. A TypeConverter
-  // for Map to std::map is defined below.
-  template <typename U>
-  U To() const {
-    return TypeConverter<U, Map>::Convert(*this);
-  }
-
-  // Destroys the contents of the Map and leaves it in the null state.
-  void reset() {
-    map_.clear();
-    is_null_ = true;
-  }
-
-  // Tests as true if non-null, false if null.
-  explicit operator bool() const { return !is_null_; }
-
-  bool is_null() const { return is_null_; }
-
-  // Indicates the number of keys in the map.
-  size_t size() const { return map_.size(); }
-
-  void mark_non_null() { is_null_ = false; }
-
-  // Inserts a key-value pair into the map, moving the value by calling its
-  // Pass() method if it is a move-only type. Like std::map, this does not
-  // insert |value| if |key| is already a member of the map.
-  void insert(const KeyType& key, ValueForwardType value) {
-    is_null_ = false;
-    Traits::Insert(&map_, key, value);
-  }
-
-  // Returns a reference to the value associated with the specified key,
-  // crashing the process if the key is not present in the map.
-  ValueType& at(const KeyType& key) { return map_.at(key); }
-  const ValueType& at(const KeyType& key) const { return map_.at(key); }
-
-  // Returns a reference to the value associated with the specified key,
-  // creating a new entry if the key is not already present in the map. A
-  // newly-created value will be value-initialized (meaning that it will be
-  // initialized by the default constructor of the value type, if any, or else
-  // will be zero-initialized).
-  ValueType& operator[](const KeyType& key) {
-    is_null_ = false;
-    return map_[key];
-  }
-
-  // Swaps the contents of this Map with another Map of the same type (including
-  // nullness).
-  void Swap(Map<KeyType, ValueType>* other) {
-    std::swap(is_null_, other->is_null_);
-    map_.swap(other->map_);
-  }
-
-  // Swaps the contents of this Map with an std::map containing keys and values
-  // of the same type. Since std::map cannot represent the null state, the
-  // std::map will be empty if Map is null. The Map will always be left in a
-  // non-null state.
-  void Swap(std::map<KeyType, ValueType>* other) {
-    is_null_ = false;
-    map_.swap(*other);
-  }
-
-  // Returns a new Map that contains a copy of the contents of this map.  If the
-  // values are of a type that is designated move-only, they will be cloned
-  // using the Clone() method of the type. Please note that calling this method
-  // will fail compilation if the value type cannot be cloned (which usually
-  // means that it is a Mojo handle type or a type that contains Mojo handles).
-  Map Clone() const {
-    Map result;
-    result.is_null_ = is_null_;
-    Traits::Clone(map_, &result.map_);
-    return result;
-  }
-
-  // Indicates whether the contents of this map are equal to those of another
-  // Map (including nullness). Keys are compared by the != operator. Values are
-  // compared as follows:
-  //   - Map, Array, Struct, or StructPtr values are compared by their Equals()
-  //     method.
-  //   - ScopedHandleBase-derived types are compared by their handles.
-  //   - Values of other types are compared by their "==" operator.
-  bool Equals(const Map& other) const {
-    if (is_null() != other.is_null())
-      return false;
-    if (size() != other.size())
-      return false;
-    auto i = cbegin();
-    auto j = other.cbegin();
-    while (i != cend()) {
-      if (i.GetKey() != j.GetKey())
-        return false;
-      if (!internal::ValueTraits<ValueType>::Equals(i.GetValue(), j.GetValue()))
-        return false;
-      ++i;
-      ++j;
-    }
-    return true;
-  }
-
- private:
-  // A Map Iterator, templated for mutable and const iterator behaviour.
-  // If |IsConstIterator| is true, the iterator behaves like a const-iterator.
-  //
-  // TODO(vardhan):  Make this adhere to the BidirectionalIterator concept.
-  enum class IteratorMutability { kConst, kMutable };
-  template <IteratorMutability MutabilityType = IteratorMutability::kMutable>
-  class InternalIterator {
-    using InternalIteratorType = typename std::conditional<
-        MutabilityType == IteratorMutability::kConst,
-        typename std::map<KeyType, ValueType>::const_iterator,
-        typename std::map<KeyType, ValueType>::iterator>::type;
-
-    using ReturnValueType =
-        typename std::conditional<MutabilityType == IteratorMutability::kConst,
-                                  const ValueType&,
-                                  ValueType&>::type;
-
-   public:
-    InternalIterator() : it_() {}
-    InternalIterator(InternalIteratorType it) : it_(it) {}
-
-    // The key is always a const reference, but the value is conditional on
-    // whether this is a const iterator or not.
-    const KeyType& GetKey() { return it_->first; }
-    ReturnValueType GetValue() { return it_->second; }
-
-    InternalIterator& operator++() {
-      ++it_;
-      return *this;
-    }
-    InternalIterator<MutabilityType> operator++(int) {
-      InternalIterator<MutabilityType> original(*this);
-      ++it_;
-      return original;
-    }
-    InternalIterator& operator--() {
-      --it_;
-      return *this;
-    }
-    InternalIterator<MutabilityType> operator--(int) {
-      InternalIterator<MutabilityType> original(*this);
-      --it_;
-      return original;
-    }
-    bool operator!=(const InternalIterator& rhs) const {
-      return it_ != rhs.it_;
-    }
-    bool operator==(const InternalIterator& rhs) const {
-      return it_ == rhs.it_;
-    }
-
-   private:
-    InternalIteratorType it_;
-  };
-
- public:
-  using MapIterator = InternalIterator<IteratorMutability::kMutable>;
-  using ConstMapIterator = InternalIterator<IteratorMutability::kConst>;
-
-  // Provide read-only and mutable iteration over map members in a way similar
-  // to STL collections.
-  ConstMapIterator cbegin() const { return ConstMapIterator(map_.cbegin()); }
-  ConstMapIterator cend() const { return ConstMapIterator(map_.cend()); }
-  MapIterator begin() { return MapIterator(map_.begin()); }
-  MapIterator end() { return MapIterator(map_.end()); }
-
-  // Returns the iterator pointing to the entry for |key|, if present, or else
-  // returns |cend()| or |end()|, respectively.
-  ConstMapIterator find(const KeyType& key) const {
-    return ConstMapIterator(map_.find(key));
-  }
-  MapIterator find(const KeyType& key) { return MapIterator(map_.find(key)); }
-
- private:
-  void Take(Map* other) {
-    reset();
-    Swap(other);
-  }
-
-  std::map<KeyType, ValueType> map_;
-  bool is_null_;
-
-  MOJO_MOVE_ONLY_TYPE(Map);
-};
-
-// Copies the contents of an std::map to a new Map, optionally changing the
-// types of the keys and values along the way using TypeConverter.
-template <typename MojoKey,
-          typename MojoValue,
-          typename STLKey,
-          typename STLValue>
-struct TypeConverter<Map<MojoKey, MojoValue>, std::map<STLKey, STLValue>> {
-  static Map<MojoKey, MojoValue> Convert(
-      const std::map<STLKey, STLValue>& input) {
-    Map<MojoKey, MojoValue> result;
-    result.mark_non_null();
-    for (auto& pair : input) {
-      result.insert(TypeConverter<MojoKey, STLKey>::Convert(pair.first),
-                    TypeConverter<MojoValue, STLValue>::Convert(pair.second));
-    }
-    return result;
-  }
-};
-
-// Copies the contents of a Map to an std::map, optionally changing the types of
-// the keys and values along the way using TypeConverter.
-template <typename MojoKey,
-          typename MojoValue,
-          typename STLKey,
-          typename STLValue>
-struct TypeConverter<std::map<STLKey, STLValue>, Map<MojoKey, MojoValue>> {
-  static std::map<STLKey, STLValue> Convert(
-      const Map<MojoKey, MojoValue>& input) {
-    std::map<STLKey, STLValue> result;
-    if (!input.is_null()) {
-      for (auto it = input.cbegin(); it != input.cend(); ++it) {
-        result.insert(std::make_pair(
-            TypeConverter<STLKey, MojoKey>::Convert(it.GetKey()),
-            TypeConverter<STLValue, MojoValue>::Convert(it.GetValue())));
-      }
-    }
-    return result;
-  }
-};
-
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_MAP_H_