Backend.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2012, 2013 Ripple Labs Inc.
 
    Permission to use, copy, modify, and/or distribute this software for any
    purpose  with  or without fee is hereby granted, provided that the above
    copyright notice and this permission notice appear in all copies.
 
    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
 
#ifndef RIPPLE_NODESTORE_BACKEND_H_INCLUDED
#define RIPPLE_NODESTORE_BACKEND_H_INCLUDED
 
#include <ripple/nodestore/Types.h>
#include <atomic>
#include <cstdint>
 
namespace ripple {
namespace NodeStore {
 
class Backend
{
public:
    template <typename T>
    struct Counters
    {
        Counters() = default;
        Counters(Counters const&) = default;
 
        template <typename U>
        Counters(Counters<U> const& other)
            : writeDurationUs(other.writeDurationUs)
            , writeRetries(other.writeRetries)
            , writesDelayed(other.writesDelayed)
            , readRetries(other.readRetries)
            , readErrors(other.readErrors)
        {
        }
 
        T writeDurationUs = {};
        T writeRetries = {};
        T writesDelayed = {};
        T readRetries = {};
        T readErrors = {};
    };
 
    virtual ~Backend() = default;
 
    virtual std::string
    getName() = 0;
 
    virtual void
    open(bool createIfMissing = true) = 0;
 
    virtual bool
    isOpen() = 0;
 
    virtual void
    close() = 0;
 
    virtual Status
    fetch(void const* key, std::shared_ptr<NodeObject>* pObject) = 0;
 
    virtual bool
    canFetchBatch() = 0;
 
    virtual std::pair<std::vector<std::shared_ptr<NodeObject>>, Status>
    fetchBatch(std::vector<uint256 const*> const& hashes) = 0;
 
    virtual void
    store(std::shared_ptr<NodeObject> const& object) = 0;
 
    virtual void
    storeBatch(Batch const& batch) = 0;
 
    virtual void
    sync() = 0;
 
    virtual void
    for_each(std::function<void(std::shared_ptr<NodeObject>)> f) = 0;
 
    virtual int
    getWriteLoad() = 0;
 
    virtual void
    setDeletePath() = 0;
 
    virtual void
    verify() = 0;
 
    virtual int
    fdRequired() const = 0;
 
    virtual std::optional<Counters<std::uint64_t>>
    counters() const
    {
        return std::nullopt;
    }
 
    bool
    backed() const
    {
        return fdRequired();
    }
};
 
}  // namespace NodeStore
}  // namespace ripple
 
#endif