DatabaseCon.h

#pragma once
 
#include <xrpl/core/PerfLog.h>
#include <xrpl/core/ServiceRegistry.h>
#include <xrpl/core/StartUpType.h>
#include <xrpl/rdb/DBInit.h>
#include <xrpl/rdb/SociDB.h>
 
#include <boost/filesystem/path.hpp>
 
#include <mutex>
#include <optional>
#include <string>
 
namespace soci {
class session;
}  // namespace soci
 
namespace xrpl {
 
class LockedSociSession
{
public:
    using mutex = std::recursive_mutex;
 
private:
    std::shared_ptr<soci::session> session_;
    std::unique_lock<mutex> lock_;
 
public:
    LockedSociSession(std::shared_ptr<soci::session> it, mutex& m)
        : session_(std::move(it)), lock_(m)
    {
    }
    LockedSociSession(LockedSociSession&& rhs) noexcept
        : session_(std::move(rhs.session_)), lock_(std::move(rhs.lock_))
    {
    }
    LockedSociSession() = delete;
    LockedSociSession(LockedSociSession const& rhs) = delete;
    LockedSociSession&
    operator=(LockedSociSession const& rhs) = delete;
 
    soci::session*
    get()
    {
        return session_.get();
    }
    soci::session&
    operator*()
    {
        return *session_;
    }
    soci::session*
    operator->()
    {
        return session_.get();
    }
    explicit
    operator bool() const
    {
        return bool(session_);
    }
};
 
class DatabaseCon
{
public:
    struct Setup
    {
        explicit Setup() = default;
 
        StartUpType startUp = StartUpType::Normal;
        bool standAlone = false;
        boost::filesystem::path dataDir;
        // Indicates whether or not to return the `globalPragma`
        // from commonPragma()
        bool useGlobalPragma = false;
 
        std::vector<std::string> const*
        commonPragma() const
        {
            XRPL_ASSERT(
                !useGlobalPragma || globalPragma,
                "xrpl::DatabaseCon::Setup::commonPragma : consistent global "
                "pragma");
            return useGlobalPragma && globalPragma ? globalPragma.get() : nullptr;
        }
 
        static std::unique_ptr<std::vector<std::string> const> globalPragma;
        std::array<std::string, 4> txPragma;
        std::array<std::string, 1> lgrPragma;
    };
 
    struct CheckpointerSetup
    {
        JobQueue* jobQueue;
        std::reference_wrapper<ServiceRegistry> registry;
    };
 
    template <std::size_t N, std::size_t M>
    DatabaseCon(
        Setup const& setup,
        std::string const& dbName,
        std::array<std::string, N> const& pragma,
        std::array<char const*, M> const& initSQL,
        beast::Journal journal)
        // Use temporary files or regular DB files?
        : DatabaseCon(
              setup.standAlone && setup.startUp != StartUpType::Load &&
                      setup.startUp != StartUpType::LoadFile && setup.startUp != StartUpType::Replay
                  ? ""
                  : (setup.dataDir / dbName),
              setup.commonPragma(),
              pragma,
              initSQL,
              journal)
    {
    }
 
    // Use this constructor to setup checkpointing
    template <std::size_t N, std::size_t M>
    DatabaseCon(
        Setup const& setup,
        std::string const& dbName,
        std::array<std::string, N> const& pragma,
        std::array<char const*, M> const& initSQL,
        CheckpointerSetup const& checkpointerSetup,
        beast::Journal journal)
        : DatabaseCon(setup, dbName, pragma, initSQL, journal)
    {
        setupCheckpointing(checkpointerSetup.jobQueue, checkpointerSetup.registry.get());
    }
 
    template <std::size_t N, std::size_t M>
    DatabaseCon(
        boost::filesystem::path const& dataDir,
        std::string const& dbName,
        std::array<std::string, N> const& pragma,
        std::array<char const*, M> const& initSQL,
        beast::Journal journal)
        : DatabaseCon(dataDir / dbName, nullptr, pragma, initSQL, journal)
    {
    }
 
    // Use this constructor to setup checkpointing
    template <std::size_t N, std::size_t M>
    DatabaseCon(
        boost::filesystem::path const& dataDir,
        std::string const& dbName,
        std::array<std::string, N> const& pragma,
        std::array<char const*, M> const& initSQL,
        CheckpointerSetup const& checkpointerSetup,
        beast::Journal journal)
        : DatabaseCon(dataDir, dbName, pragma, initSQL, journal)
    {
        setupCheckpointing(checkpointerSetup.jobQueue, checkpointerSetup.registry.get());
    }
 
    ~DatabaseCon();
 
    soci::session&
    getSession()
    {
        return *session_;
    }
 
    LockedSociSession
    checkoutDb()
    {
        using namespace std::chrono_literals;
        LockedSociSession session = perf::measureDurationAndLog(
            [&]() { return LockedSociSession(session_, lock_); }, "checkoutDb", 10ms, j_);
 
        return session;
    }
 
private:
    void
    setupCheckpointing(JobQueue*, ServiceRegistry&);
 
    template <std::size_t N, std::size_t M>
    DatabaseCon(
        boost::filesystem::path const& pPath,
        std::vector<std::string> const* commonPragma,
        std::array<std::string, N> const& pragma,
        std::array<char const*, M> const& initSQL,
        beast::Journal journal)
        : session_(std::make_shared<soci::session>()), j_(journal)
    {
        open(*session_, "sqlite", pPath.string());
 
        for (auto const& p : pragma)
        {
            soci::statement st = session_->prepare << p;
            st.execute(true);
        }
 
        if (commonPragma)
        {
            for (auto const& p : *commonPragma)
            {
                soci::statement st = session_->prepare << p;
                st.execute(true);
            }
        }
 
        for (auto const& sql : initSQL)
        {
            soci::statement st = session_->prepare << sql;
            st.execute(true);
        }
    }
 
    LockedSociSession::mutex lock_;
 
    // checkpointer may outlive the DatabaseCon when the checkpointer jobQueue
    // callback locks a weak pointer and the DatabaseCon is then destroyed. In
    // this case, the checkpointer needs to make sure it doesn't use an already
    // destroyed session. Thus this class keeps a shared_ptr to the session (so
    // the checkpointer can keep a weak_ptr) and the checkpointer is a
    // shared_ptr in this class. session_ will never be null.
    std::shared_ptr<soci::session> const session_;
    std::shared_ptr<Checkpointer> checkpointer_;
 
    beast::Journal const j_;
};
 
// Return the checkpointer from its id. If the checkpointer no longer exists, an
// nullptr is returned
std::shared_ptr<Checkpointer>
checkpointerFromId(std::uintptr_t id);
 
}  // namespace xrpl