ValidatorSite.h

//------------------------------------------------------------------------------
/*
    This file is part of rippled: https://github.com/ripple/rippled
    Copyright (c) 2016 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_APP_MISC_VALIDATORSITE_H_INCLUDED
#define RIPPLE_APP_MISC_VALIDATORSITE_H_INCLUDED
 
#include <xrpld/app/main/Application.h>
#include <xrpld/app/misc/ValidatorList.h>
#include <xrpld/app/misc/detail/Work.h>
 
#include <xrpl/basics/Log.h>
#include <xrpl/basics/StringUtilities.h>
#include <xrpl/json/json_value.h>
 
#include <boost/asio.hpp>
 
#include <mutex>
#include <optional>
 
namespace ripple {
 
class ValidatorSite
{
    friend class Work;
 
private:
    using error_code = boost::system::error_code;
    using clock_type = std::chrono::system_clock;
    using endpoint_type = boost::asio::ip::tcp::endpoint;
 
    struct Site
    {
        struct Status
        {
            clock_type::time_point refreshed;
            ListDisposition disposition;
            std::string message;
        };
 
        struct Resource
        {
            explicit Resource(std::string uri_);
            std::string const uri;
            parsedURL pUrl;
        };
 
        explicit Site(std::string uri);
 
        std::shared_ptr<Resource> loadedResource;
 
        std::shared_ptr<Resource> startingResource;
 
        std::shared_ptr<Resource> activeResource;
 
        unsigned short redirCount;
        std::chrono::minutes refreshInterval;
        clock_type::time_point nextRefresh;
        std::optional<Status> lastRefreshStatus;
        endpoint_type lastRequestEndpoint;
        bool lastRequestSuccessful;
    };
 
    Application& app_;
    beast::Journal const j_;
 
    // If both mutex are to be locked at the same time, `sites_mutex_` must be
    // locked before `state_mutex_` or we may deadlock.
    std::mutex mutable sites_mutex_;
    std::mutex mutable state_mutex_;
 
    std::condition_variable cv_;
    std::weak_ptr<detail::Work> work_;
    boost::asio::basic_waitable_timer<clock_type> timer_;
 
    // A list is currently being fetched from a site
    std::atomic<bool> fetching_;
 
    // One or more lists are due to be fetched
    std::atomic<bool> pending_;
    std::atomic<bool> stopping_;
 
    // The configured list of URIs for fetching lists
    std::vector<Site> sites_;
 
    // time to allow for requests to complete
    std::chrono::seconds const requestTimeout_;
 
public:
    ValidatorSite(
        Application& app,
        std::optional<beast::Journal> j = std::nullopt,
        std::chrono::seconds timeout = std::chrono::seconds{20});
    ~ValidatorSite();
 
    bool
    load(std::vector<std::string> const& siteURIs);
 
    void
    start();
 
    void
    join();
 
    void
    stop();
 
    Json::Value
    getJson() const;
 
private:
    bool
    load(
        std::vector<std::string> const& siteURIs,
        std::lock_guard<std::mutex> const&);
 
    void
    setTimer(
        std::lock_guard<std::mutex> const&,
        std::lock_guard<std::mutex> const&);
 
    void
    onRequestTimeout(std::size_t siteIdx, error_code const& ec);
 
    void
    onTimer(std::size_t siteIdx, error_code const& ec);
 
    void
    onSiteFetch(
        boost::system::error_code const& ec,
        endpoint_type const& endpoint,
        detail::response_type&& res,
        std::size_t siteIdx);
 
    void
    onTextFetch(
        boost::system::error_code const& ec,
        std::string const& res,
        std::size_t siteIdx);
 
    void
    makeRequest(
        std::shared_ptr<Site::Resource> resource,
        std::size_t siteIdx,
        std::lock_guard<std::mutex> const&);
 
    void
    parseJsonResponse(
        std::string const& res,
        std::size_t siteIdx,
        std::lock_guard<std::mutex> const&);
 
    std::shared_ptr<Site::Resource>
    processRedirect(
        detail::response_type& res,
        std::size_t siteIdx,
        std::lock_guard<std::mutex> const&);
 
    bool
    missingSite(std::lock_guard<std::mutex> const&);
};
 
}  // namespace ripple
 
#endif