safe_point.h

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#pragma once
 
#include <neograph/api.h>
#include <neograph/graph/checkpoint.h>
 
#include <memory>
#include <optional>
#include <string>
 
namespace neograph::graph {
 
class GraphEngine;
class CancelToken;
 
struct GraphGenerationIdentity {
    std::string core_name;
    std::string core_generation_id;
 
    bool operator==(const GraphGenerationIdentity&) const = default;
};
 
class NEOGRAPH_API GraphSafePoint final {
public:
    GraphSafePoint(const GraphSafePoint&) = default;
    GraphSafePoint& operator=(const GraphSafePoint&) = default;
 
    const GraphGenerationIdentity& generation() const noexcept;
    const Checkpoint& checkpoint() const noexcept;
 
private:
    struct Impl;
    GraphSafePoint(GraphGenerationIdentity generation, Checkpoint checkpoint);
    std::shared_ptr<const Impl> impl_;
 
    friend class GraphSafePointRequest;
};
 
class NEOGRAPH_API GraphSafePointRequest final {
public:
    explicit GraphSafePointRequest(GraphGenerationIdentity expected_generation);
    GraphSafePointRequest(const GraphSafePointRequest&) = delete;
    GraphSafePointRequest& operator=(const GraphSafePointRequest&) = delete;
    ~GraphSafePointRequest();
 
    bool request() noexcept;
    bool requested() const noexcept;
    bool captured() const noexcept;
    bool closed() const noexcept;
    GraphGenerationIdentity expected_generation() const;
    std::optional<GraphSafePoint> safe_point() const;
 
private:
    struct Impl;
    std::unique_ptr<Impl> impl_;
 
    bool attach(const GraphGenerationIdentity& generation) noexcept;
    bool capture(const GraphGenerationIdentity& generation,
                 Checkpoint checkpoint,
                 const CancelToken* cancellation);
    void close() noexcept;
    void reject() noexcept;
 
    friend class GraphEngine;
};
 
}  // namespace neograph::graph