memgraph/src/storage/v2/storage.cpp

// 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 "storage/v2/storage.hpp"

namespace memgraph::storage {

using OOMExceptionEnabler = utils::MemoryTracker::OutOfMemoryExceptionEnabler;

auto AdvanceToVisibleVertex(utils::SkipList<Vertex>::Iterator it, utils::SkipList<Vertex>::Iterator end,
                            std::optional<VertexAccessor> *vertex, Transaction *tx, View view, Indices *indices,
                            Constraints *constraints, Config::Items config) {
  while (it != end) {
    *vertex = VertexAccessor::Create(&*it, tx, indices, constraints, config, view);
    if (!*vertex) {
      ++it;
      continue;
    }
    break;
  }
  return it;
}

AllVerticesIterable::Iterator::Iterator(AllVerticesIterable *self, utils::SkipList<Vertex>::Iterator it)
    : self_(self),
      it_(AdvanceToVisibleVertex(it, self->vertices_accessor_.end(), &self->vertex_, self->transaction_, self->view_,
                                 self->indices_, self_->constraints_, self->config_)) {}

VertexAccessor AllVerticesIterable::Iterator::operator*() const { return *self_->vertex_; }

AllVerticesIterable::Iterator &AllVerticesIterable::Iterator::operator++() {
  ++it_;
  it_ = AdvanceToVisibleVertex(it_, self_->vertices_accessor_.end(), &self_->vertex_, self_->transaction_, self_->view_,
                               self_->indices_, self_->constraints_, self_->config_);
  return *this;
}

VerticesIterable::VerticesIterable(AllVerticesIterable vertices) : type_(Type::ALL) {
  new (&all_vertices_) AllVerticesIterable(std::move(vertices));
}

VerticesIterable::VerticesIterable(LabelIndex::Iterable vertices) : type_(Type::BY_LABEL) {
  new (&vertices_by_label_) LabelIndex::Iterable(std::move(vertices));
}

VerticesIterable::VerticesIterable(LabelPropertyIndex::Iterable vertices) : type_(Type::BY_LABEL_PROPERTY) {
  new (&vertices_by_label_property_) LabelPropertyIndex::Iterable(std::move(vertices));
}

VerticesIterable::VerticesIterable(VerticesIterable &&other) noexcept : type_(other.type_) {
  switch (other.type_) {
    case Type::ALL:
      new (&all_vertices_) AllVerticesIterable(std::move(other.all_vertices_));
      break;
    case Type::BY_LABEL:
      new (&vertices_by_label_) LabelIndex::Iterable(std::move(other.vertices_by_label_));
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&vertices_by_label_property_) LabelPropertyIndex::Iterable(std::move(other.vertices_by_label_property_));
      break;
  }
}

VerticesIterable &VerticesIterable::operator=(VerticesIterable &&other) noexcept {
  switch (type_) {
    case Type::ALL:
      all_vertices_.AllVerticesIterable::~AllVerticesIterable();
      break;
    case Type::BY_LABEL:
      vertices_by_label_.LabelIndex::Iterable::~Iterable();
      break;
    case Type::BY_LABEL_PROPERTY:
      vertices_by_label_property_.LabelPropertyIndex::Iterable::~Iterable();
      break;
  }
  type_ = other.type_;
  switch (other.type_) {
    case Type::ALL:
      new (&all_vertices_) AllVerticesIterable(std::move(other.all_vertices_));
      break;
    case Type::BY_LABEL:
      new (&vertices_by_label_) LabelIndex::Iterable(std::move(other.vertices_by_label_));
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&vertices_by_label_property_) LabelPropertyIndex::Iterable(std::move(other.vertices_by_label_property_));
      break;
  }
  return *this;
}

VerticesIterable::~VerticesIterable() {
  switch (type_) {
    case Type::ALL:
      all_vertices_.AllVerticesIterable::~AllVerticesIterable();
      break;
    case Type::BY_LABEL:
      vertices_by_label_.LabelIndex::Iterable::~Iterable();
      break;
    case Type::BY_LABEL_PROPERTY:
      vertices_by_label_property_.LabelPropertyIndex::Iterable::~Iterable();
      break;
  }
}

VerticesIterable::Iterator VerticesIterable::begin() {
  switch (type_) {
    case Type::ALL:
      return Iterator(all_vertices_.begin());
    case Type::BY_LABEL:
      return Iterator(vertices_by_label_.begin());
    case Type::BY_LABEL_PROPERTY:
      return Iterator(vertices_by_label_property_.begin());
  }
}

VerticesIterable::Iterator VerticesIterable::end() {
  switch (type_) {
    case Type::ALL:
      return Iterator(all_vertices_.end());
    case Type::BY_LABEL:
      return Iterator(vertices_by_label_.end());
    case Type::BY_LABEL_PROPERTY:
      return Iterator(vertices_by_label_property_.end());
  }
}

VerticesIterable::Iterator::Iterator(AllVerticesIterable::Iterator it) : type_(Type::ALL) {
  new (&all_it_) AllVerticesIterable::Iterator(std::move(it));
}

VerticesIterable::Iterator::Iterator(LabelIndex::Iterable::Iterator it) : type_(Type::BY_LABEL) {
  new (&by_label_it_) LabelIndex::Iterable::Iterator(std::move(it));
}

VerticesIterable::Iterator::Iterator(LabelPropertyIndex::Iterable::Iterator it) : type_(Type::BY_LABEL_PROPERTY) {
  new (&by_label_property_it_) LabelPropertyIndex::Iterable::Iterator(std::move(it));
}

VerticesIterable::Iterator::Iterator(const VerticesIterable::Iterator &other) : type_(other.type_) {
  switch (other.type_) {
    case Type::ALL:
      new (&all_it_) AllVerticesIterable::Iterator(other.all_it_);
      break;
    case Type::BY_LABEL:
      new (&by_label_it_) LabelIndex::Iterable::Iterator(other.by_label_it_);
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&by_label_property_it_) LabelPropertyIndex::Iterable::Iterator(other.by_label_property_it_);
      break;
  }
}

VerticesIterable::Iterator &VerticesIterable::Iterator::operator=(const VerticesIterable::Iterator &other) {
  Destroy();
  type_ = other.type_;
  switch (other.type_) {
    case Type::ALL:
      new (&all_it_) AllVerticesIterable::Iterator(other.all_it_);
      break;
    case Type::BY_LABEL:
      new (&by_label_it_) LabelIndex::Iterable::Iterator(other.by_label_it_);
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&by_label_property_it_) LabelPropertyIndex::Iterable::Iterator(other.by_label_property_it_);
      break;
  }
  return *this;
}

VerticesIterable::Iterator::Iterator(VerticesIterable::Iterator &&other) noexcept : type_(other.type_) {
  switch (other.type_) {
    case Type::ALL:
      new (&all_it_) AllVerticesIterable::Iterator(std::move(other.all_it_));
      break;
    case Type::BY_LABEL:
      new (&by_label_it_) LabelIndex::Iterable::Iterator(std::move(other.by_label_it_));
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&by_label_property_it_) LabelPropertyIndex::Iterable::Iterator(std::move(other.by_label_property_it_));
      break;
  }
}

VerticesIterable::Iterator &VerticesIterable::Iterator::operator=(VerticesIterable::Iterator &&other) noexcept {
  Destroy();
  type_ = other.type_;
  switch (other.type_) {
    case Type::ALL:
      new (&all_it_) AllVerticesIterable::Iterator(std::move(other.all_it_));
      break;
    case Type::BY_LABEL:
      new (&by_label_it_) LabelIndex::Iterable::Iterator(std::move(other.by_label_it_));
      break;
    case Type::BY_LABEL_PROPERTY:
      new (&by_label_property_it_) LabelPropertyIndex::Iterable::Iterator(std::move(other.by_label_property_it_));
      break;
  }
  return *this;
}

VerticesIterable::Iterator::~Iterator() { Destroy(); }

void VerticesIterable::Iterator::Destroy() noexcept {
  switch (type_) {
    case Type::ALL:
      all_it_.AllVerticesIterable::Iterator::~Iterator();
      break;
    case Type::BY_LABEL:
      by_label_it_.LabelIndex::Iterable::Iterator::~Iterator();
      break;
    case Type::BY_LABEL_PROPERTY:
      by_label_property_it_.LabelPropertyIndex::Iterable::Iterator::~Iterator();
      break;
  }
}

VertexAccessor VerticesIterable::Iterator::operator*() const {
  switch (type_) {
    case Type::ALL:
      return *all_it_;
    case Type::BY_LABEL:
      return *by_label_it_;
    case Type::BY_LABEL_PROPERTY:
      return *by_label_property_it_;
  }
}

VerticesIterable::Iterator &VerticesIterable::Iterator::operator++() {
  switch (type_) {
    case Type::ALL:
      ++all_it_;
      break;
    case Type::BY_LABEL:
      ++by_label_it_;
      break;
    case Type::BY_LABEL_PROPERTY:
      ++by_label_property_it_;
      break;
  }
  return *this;
}

bool VerticesIterable::Iterator::operator==(const Iterator &other) const {
  switch (type_) {
    case Type::ALL:
      return all_it_ == other.all_it_;
    case Type::BY_LABEL:
      return by_label_it_ == other.by_label_it_;
    case Type::BY_LABEL_PROPERTY:
      return by_label_property_it_ == other.by_label_property_it_;
  }
}

Storage::Accessor::Accessor(Storage *storage, IsolationLevel isolation_level, StorageMode storage_mode)
    : storage_(storage),
      // The lock must be acquired before creating the transaction object to
      // prevent freshly created transactions from dangling in an active state
      // during exclusive operations.
      storage_guard_(storage_->main_lock_),
      transaction_(storage->CreateTransaction(isolation_level, storage_mode)),
      is_transaction_active_(true) {}

Storage::Accessor::Accessor(Accessor &&other) noexcept
    : storage_(other.storage_),
      storage_guard_(std::move(other.storage_guard_)),
      transaction_(std::move(other.transaction_)),
      commit_timestamp_(other.commit_timestamp_),
      is_transaction_active_(other.is_transaction_active_) {
  // Don't allow the other accessor to abort our transaction in destructor.
  other.is_transaction_active_ = false;
  other.commit_timestamp_.reset();
}

}  // namespace memgraph::storage