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memgraph/src/query/frame_change.hpp
2023-05-29 17:52:20 +02:00

123 lines
4.3 KiB
C++

// Copyright 2023 Memgraph Ltd.
//
// Use of this software is governed by the Business Source License
// included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
// License, and you may not use this file except in compliance with the Business Source License.
//
// As of the Change Date specified in that file, in accordance with
// the Business Source License, use of this software will be governed
// by the Apache License, Version 2.0, included in the file
// licenses/APL.txt.
#include "query/typed_value.hpp"
#include "utils/memory.hpp"
#include "utils/pmr/unordered_map.hpp"
#include "utils/pmr/vector.hpp"
namespace memgraph::query {
// Key is hash output, value is vector of unique elements
using CachedType = utils::pmr::unordered_map<size_t, std::vector<TypedValue>>;
struct CachedValue {
// Cached value, this can be probably templateized
CachedType cache_;
explicit CachedValue(utils::MemoryResource *mem) : cache_(mem) {}
CachedValue(CachedType &&cache, memgraph::utils::MemoryResource *memory) : cache_(std::move(cache), memory) {}
CachedValue(const CachedValue &other, memgraph::utils::MemoryResource *memory) : cache_(other.cache_, memory) {}
CachedValue(CachedValue &&other, memgraph::utils::MemoryResource *memory) : cache_(std::move(other.cache_), memory) {}
CachedValue(CachedValue &&other) noexcept = delete;
/// Copy construction without memgraph::utils::MemoryResource is not allowed.
CachedValue(const CachedValue &) = delete;
CachedValue &operator=(const CachedValue &) = delete;
CachedValue &operator=(CachedValue &&) = delete;
~CachedValue() = default;
memgraph::utils::MemoryResource *GetMemoryResource() const noexcept {
return cache_.get_allocator().GetMemoryResource();
}
// Func to check if cache_ contains value
bool CacheValue(const TypedValue &value) {
if (!value.IsList()) {
return false;
}
const auto &list = value.ValueList();
TypedValue::Hash hash{};
for (const TypedValue &element : list) {
const auto key = hash(element);
auto &vector_values = cache_[key];
if (!IsValueInVec(vector_values, element)) {
vector_values.push_back(element);
}
}
return true;
}
// Func to cache_value inside cache_
bool ContainsValue(const TypedValue &value) const {
TypedValue::Hash hash{};
const auto key = hash(value);
if (cache_.contains(key)) {
return IsValueInVec(cache_.at(key), value);
}
return false;
}
private:
bool IsValueInVec(const std::vector<TypedValue> &vec_values, const TypedValue &value) const {
return std::any_of(vec_values.begin(), vec_values.end(), [&value](auto &vec_value) {
const auto is_value_equal = vec_value == value;
if (is_value_equal.IsNull()) return false;
return is_value_equal.ValueBool();
});
}
};
// Class tracks keys for which user can cache values which help with faster search or faster retrieval
// in the future.
class FrameChangeCollector {
public:
explicit FrameChangeCollector(utils::MemoryResource *mem) : tracked_values_(mem){};
// Add tracking key to cache later value
CachedValue &AddTrackingKey(const std::string &key) {
const auto &[it, _] = tracked_values_.emplace(key, tracked_values_.get_allocator().GetMemoryResource());
return it->second;
}
// Is key tracked
bool IsKeyTracked(const std::string &key) const { return tracked_values_.contains(key); }
// Is value for given key cached
bool IsKeyValueCached(const std::string &key) const {
return tracked_values_.contains(key) && !tracked_values_.at(key).cache_.empty();
}
// Reset value for tracking key
bool ResetTrackingValue(const std::string &key) {
if (tracked_values_.contains(key)) {
tracked_values_.erase(key);
AddTrackingKey(key);
}
return true;
}
// Get value cached for tracking key, throws if key is not in tracked
CachedValue &GetCachedValue(const std::string &key) { return tracked_values_.at(key); }
// Checks for keys tracked
bool IsTrackingValues() const { return !tracked_values_.empty(); }
private:
// Key is output of utils::GetFrameChangeId, value is utils::pmr::unordered_map
memgraph::utils::pmr::unordered_map<std::string, CachedValue> tracked_values_;
};
} // namespace memgraph::query