events.h

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// Copyright (c) 2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_SUPPORT_EVENTS_H
#define BITCOIN_SUPPORT_EVENTS_H
 
#include <ios>
#include <memory>
 
#include <event2/event.h>
#include <event2/http.h>
 
#define MAKE_RAII(type)                                                        \
    /* deleter */                                                              \
    struct type##_deleter {                                                    \
        void operator()(struct type *ob) {                                     \
            type##_free(ob);                                                   \
        }                                                                      \
    };                                                                         \
    /* unique ptr typedef */                                                   \
    typedef std::unique_ptr<struct type, type##_deleter> raii_##type
 
MAKE_RAII(event_base);
MAKE_RAII(event);
MAKE_RAII(evhttp);
MAKE_RAII(evhttp_request);
MAKE_RAII(evhttp_connection);
 
inline raii_event_base obtain_event_base() {
    auto result = raii_event_base(event_base_new());
    if (!result.get()) {
        throw std::runtime_error("cannot create event_base");
    }
    return result;
}
 
inline raii_event obtain_event(struct event_base *base, evutil_socket_t s,
                               short events, event_callback_fn cb, void *arg) {
    return raii_event(event_new(base, s, events, cb, arg));
}
 
inline raii_evhttp obtain_evhttp(struct event_base *base) {
    return raii_evhttp(evhttp_new(base));
}
 
inline raii_evhttp_request
obtain_evhttp_request(void (*cb)(struct evhttp_request *, void *), void *arg) {
    return raii_evhttp_request(evhttp_request_new(cb, arg));
}
 
inline raii_evhttp_connection
obtain_evhttp_connection_base(struct event_base *base, std::string host,
                              uint16_t port) {
    auto result = raii_evhttp_connection(
        evhttp_connection_base_new(base, nullptr, host.c_str(), port));
    if (!result.get()) {
        throw std::runtime_error("create connection failed");
    }
    return result;
}
 
#endif // BITCOIN_SUPPORT_EVENTS_H