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cc / base / list_container_helper.h [blame]
// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_BASE_LIST_CONTAINER_HELPER_H_
#define CC_BASE_LIST_CONTAINER_HELPER_H_
#include <stddef.h>
#include <memory>
#include "base/memory/raw_ptr_exclusion.h"
#include "cc/base/base_export.h"
namespace cc {
// Helper class for ListContainer non-templated logic. All methods are private,
// and only exposed to friend classes.
// For usage, see comments in ListContainer (list_container.h).
class CC_BASE_EXPORT ListContainerHelper final {
private:
template <typename T>
friend class ListContainer;
explicit ListContainerHelper(size_t alignment,
size_t max_size_for_derived_class,
size_t num_of_elements_to_reserve_for);
ListContainerHelper(const ListContainerHelper&) = delete;
~ListContainerHelper();
ListContainerHelper& operator=(const ListContainerHelper&) = delete;
// This class deals only with char* and void*. It does allocation and passing
// out raw pointers, as well as memory deallocation when being destroyed.
class CharAllocator;
// This class points to a certain position inside memory of
// CharAllocator. It is a base class for ListContainer iterators.
struct CC_BASE_EXPORT PositionInCharAllocator {
// `ptr_to_container` is not a raw_ptr<...> for performance reasons (based
// on analysis of sampling profiler data and tab_search:top100:2020).
RAW_PTR_EXCLUSION CharAllocator* ptr_to_container = nullptr;
size_t vector_index = 0;
// `item_iterator` is not a raw_ptr<...> for performance reasons (based on
// analysis of sampling profiler data and tab_search:top100:2020).
RAW_PTR_EXCLUSION char* item_iterator = nullptr;
PositionInCharAllocator() = default;
PositionInCharAllocator(const PositionInCharAllocator& other);
PositionInCharAllocator& operator=(const PositionInCharAllocator& other);
PositionInCharAllocator(CharAllocator* container,
size_t vector_ind,
char* item_iter);
bool operator==(const PositionInCharAllocator& other) const;
bool operator!=(const PositionInCharAllocator& other) const;
PositionInCharAllocator Increment();
PositionInCharAllocator ReverseIncrement();
};
// Iterator classes that can be used to access data.
/////////////////////////////////////////////////////////////////
class CC_BASE_EXPORT Iterator : public PositionInCharAllocator {
// This class is only defined to forward iterate through
// CharAllocator.
public:
Iterator() = default;
Iterator(CharAllocator* container,
size_t vector_ind,
char* item_iter,
size_t index);
~Iterator();
size_t index() const;
protected:
// This is used to track how many increment has happened since begin(). It
// is used to avoid double increment at places an index reference is
// needed. For iterator this means begin() corresponds to index 0 and end()
// corresponds to index |size|.
size_t index_ = 0;
};
class CC_BASE_EXPORT ConstIterator : public PositionInCharAllocator {
// This class is only defined to forward iterate through
// CharAllocator.
public:
ConstIterator() = default;
ConstIterator(CharAllocator* container,
size_t vector_ind,
char* item_iter,
size_t index);
ConstIterator(const Iterator& other); // NOLINT
~ConstIterator();
size_t index() const;
protected:
// This is used to track how many increment has happened since begin(). It
// is used to avoid double increment at places an index reference is
// needed. For iterator this means begin() corresponds to index 0 and end()
// corresponds to index |size|.
size_t index_ = 0;
};
class CC_BASE_EXPORT ReverseIterator : public PositionInCharAllocator {
// This class is only defined to reverse iterate through
// CharAllocator.
public:
ReverseIterator() = default;
ReverseIterator(CharAllocator* container,
size_t vector_ind,
char* item_iter,
size_t index);
~ReverseIterator();
size_t index() const;
protected:
// This is used to track how many increment has happened since rbegin(). It
// is used to avoid double increment at places an index reference is
// needed. For reverse iterator this means rbegin() corresponds to index 0
// and rend() corresponds to index |size|.
size_t index_ = 0;
};
class CC_BASE_EXPORT ConstReverseIterator : public PositionInCharAllocator {
// This class is only defined to reverse iterate through
// CharAllocator.
public:
ConstReverseIterator() = default;
ConstReverseIterator(CharAllocator* container,
size_t vector_ind,
char* item_iter,
size_t index);
ConstReverseIterator(const ReverseIterator& other); // NOLINT
~ConstReverseIterator();
size_t index() const;
protected:
// This is used to track how many increment has happened since rbegin(). It
// is used to avoid double increment at places an index reference is
// needed. For reverse iterator this means rbegin() corresponds to index 0
// and rend() corresponds to index |size|.
size_t index_ = 0;
};
// Unlike the ListContainer methods, these do not invoke element destructors.
void RemoveLast();
void EraseAndInvalidateAllPointers(Iterator* position);
void InsertBeforeAndInvalidateAllPointers(Iterator* position,
size_t number_of_elements);
ConstReverseIterator crbegin() const;
ConstReverseIterator crend() const;
ReverseIterator rbegin();
ReverseIterator rend();
ConstIterator cbegin() const;
ConstIterator cend() const;
Iterator begin();
Iterator end();
Iterator IteratorAt(size_t index);
ConstIterator IteratorAt(size_t index) const;
size_t size() const;
bool empty() const;
size_t MaxSizeForDerivedClass() const;
size_t GetCapacityInBytes() const;
// Unlike the ListContainer method, this one does not invoke element
// destructors.
void clear();
size_t AvailableSizeWithoutAnotherAllocationForTesting() const;
// Hands out memory location for an element at the end of data structure.
void* Allocate(size_t alignment, size_t size_of_actual_element_in_bytes);
std::unique_ptr<CharAllocator> data_;
};
} // namespace cc
#endif // CC_BASE_LIST_CONTAINER_HELPER_H_