stream.h

#ifndef UVW_STREAM_INCLUDE_H
#define UVW_STREAM_INCLUDE_H
 
#include <algorithm>
#include <cstddef>
#include <iterator>
#include <memory>
#include <utility>
#include <uv.h>
#include "config.h"
#include "handle.hpp"
#include "loop.h"
#include "request.hpp"
 
namespace uvw {

struct connect_event {};

struct end_event {};

struct listen_event {};

struct shutdown_event {};

struct write_event {};

struct data_event {
    explicit data_event(std::unique_ptr<char[]> buf, std::size_t len) noexcept;
 
    std::unique_ptr<char[]> data; 
    std::size_t length;           
};
 
namespace details {
 
class connect_req final: public request<connect_req, uv_connect_t, connect_event> {
    static void connect_callback(uv_connect_t *req, int status);
 
public:
    using request::request;
 
    template<typename F, typename... Args>
    auto connect(F &&f, Args &&...args) -> std::enable_if_t<std::is_same_v<decltype(std::forward<F>(f)(raw(), std::forward<Args>(args)..., &connect_callback)), void>, int> {
        std::forward<F>(f)(raw(), std::forward<Args>(args)..., &connect_callback);
        return this->leak_if(0);
    }
 
    template<typename F, typename... Args>
    auto connect(F &&f, Args &&...args) -> std::enable_if_t<!std::is_same_v<decltype(std::forward<F>(f)(raw(), std::forward<Args>(args)..., &connect_callback)), void>, int> {
        return this->leak_if(std::forward<F>(f)(raw(), std::forward<Args>(args)..., &connect_callback));
    }
};
 
class shutdown_req final: public request<shutdown_req, uv_shutdown_t, shutdown_event> {
    static void shoutdown_callback(uv_shutdown_t *req, int status);
 
public:
    using request::request;
 
    int shutdown(uv_stream_t *hndl);
};
 
template<typename Deleter>
class write_req final: public request<write_req<Deleter>, uv_write_t, write_event> {
    static void write_callback(uv_write_t *req, int status) {
        if(auto ptr = request<write_req<Deleter>, uv_write_t, write_event>::reserve(req); status) {
            ptr->publish(error_event{status});
        } else {
            ptr->publish(write_event{});
        }
    }
 
public:
    write_req(loop::token token, std::shared_ptr<loop> parent, std::unique_ptr<char[], Deleter> dt, unsigned int len)
        : request<write_req<Deleter>, uv_write_t, write_event>{token, std::move(parent)},
          data{std::move(dt)},
          buf{uv_buf_init(data.get(), len)} {}
 
    int write(uv_stream_t *hndl) {
        return this->leak_if(uv_write(this->raw(), hndl, &buf, 1, &write_callback));
    }
 
    int write(uv_stream_t *hndl, uv_stream_t *send) {
        return this->leak_if(uv_write2(this->raw(), hndl, &buf, 1, send, &write_callback));
    }
 
private:
    std::unique_ptr<char[], Deleter> data;
    uv_buf_t buf;
};
 
} // namespace details

template<typename T, typename U, typename... E>
class stream_handle: public handle<T, U, listen_event, end_event, connect_event, shutdown_event, data_event, write_event, E...> {
    using base = handle<T, U, listen_event, end_event, connect_event, shutdown_event, data_event, write_event, E...>;
 
    template<typename, typename, typename...>
    friend class stream_handle;
 
    static constexpr unsigned int DEFAULT_BACKLOG = 128;
 
    static void read_callback(uv_stream_t *hndl, ssize_t nread, const uv_buf_t *buf) {
        T &ref = *(static_cast<T *>(hndl->data));
        // data will be destroyed no matter of what the value of nread is
        std::unique_ptr<char[]> data{buf->base};
 
        // nread == 0 is ignored (see http://docs.libuv.org/en/v1.x/stream.html)
        // equivalent to EAGAIN/EWOULDBLOCK, it shouldn't be treated as an error
        // for we don't have data to emit though, it's fine to suppress it
 
        if(nread == UV_EOF) {
            // end of stream
            ref.publish(end_event{});
        } else if(nread > 0) {
            // data available
            ref.publish(data_event{std::move(data), static_cast<std::size_t>(nread)});
        } else if(nread < 0) {
            // transmission error
            ref.publish(error_event(nread));
        }
    }
 
    static void listen_callback(uv_stream_t *hndl, int status) {
        if(T &ref = *(static_cast<T *>(hndl->data)); status) {
            ref.publish(error_event{status});
        } else {
            ref.publish(listen_event{});
        }
    }
 
    uv_stream_t *as_uv_stream() {
        return reinterpret_cast<uv_stream_t *>(this->raw());
    }
 
    const uv_stream_t *as_uv_stream() const {
        return reinterpret_cast<const uv_stream_t *>(this->raw());
    }
 
public:
#ifdef _MSC_VER
    stream_handle(loop::token token, std::shared_ptr<loop> ref)
        : base{token, std::move(ref)} {}
#else
    using base::base;
#endif

    int shutdown() {
        auto listener = [ptr = this->shared_from_this()](const auto &event, const auto &) {
            ptr->publish(event);
        };
 
        auto shutdown = this->parent().template resource<details::shutdown_req>();
        shutdown->template on<error_event>(listener);
        shutdown->template on<shutdown_event>(listener);
 
        return shutdown->shutdown(as_uv_stream());
    }

    int listen(int backlog = DEFAULT_BACKLOG) {
        return uv_listen(as_uv_stream(), backlog, &listen_callback);
    }

    template<typename S>
    int accept(S &ref) {
        return uv_accept(as_uv_stream(), ref.as_uv_stream());
    }

    int read() {
        return uv_read_start(as_uv_stream(), &details::common_alloc_callback, &read_callback);
    }

    template<auto Alloc>
    int read() {
        return uv_read_start(as_uv_stream(), &details::common_alloc_callback<T, Alloc>, &read_callback);
    }

    int stop() {
        return uv_read_stop(as_uv_stream());
    }

    template<typename Deleter>
    int write(std::unique_ptr<char[], Deleter> data, unsigned int len) {
        auto req = this->parent().template resource<details::write_req<Deleter>>(std::move(data), len);
        auto listener = [ptr = this->shared_from_this()](const auto &event, const auto &) {
            ptr->publish(event);
        };
 
        req->template on<error_event>(listener);
        req->template on<write_event>(listener);
 
        return req->write(as_uv_stream());
    }

    int write(char *data, unsigned int len) {
        auto req = this->parent().template resource<details::write_req<void (*)(char *)>>(std::unique_ptr<char[], void (*)(char *)>{data, [](char *) {}}, len);
        auto listener = [ptr = this->shared_from_this()](const auto &event, const auto &) {
            ptr->publish(event);
        };
 
        req->template on<error_event>(listener);
        req->template on<write_event>(listener);
 
        return req->write(as_uv_stream());
    }

    template<typename S, typename Deleter>
    int write(S &send, std::unique_ptr<char[], Deleter> data, unsigned int len) {
        auto req = this->parent().template resource<details::write_req<Deleter>>(std::move(data), len);
        auto listener = [ptr = this->shared_from_this()](const auto &event, const auto &) {
            ptr->publish(event);
        };
 
        req->template on<error_event>(listener);
        req->template on<write_event>(listener);
 
        return req->write(as_uv_stream(), send.as_uv_stream());
    }

    template<typename S>
    int write(S &send, char *data, unsigned int len) {
        auto req = this->parent().template resource<details::write_req<void (*)(char *)>>(std::unique_ptr<char[], void (*)(char *)>{data, [](char *) {}}, len);
        auto listener = [ptr = this->shared_from_this()](const auto &event, const auto &) {
            ptr->publish(event);
        };
 
        req->template on<error_event>(listener);
        req->template on<write_event>(listener);
 
        return req->write(as_uv_stream(), send.as_uv_stream());
    }

    int try_write(std::unique_ptr<char[]> data, unsigned int len) {
        uv_buf_t bufs[] = {uv_buf_init(data.get(), len)};
        return uv_try_write(as_uv_stream(), bufs, 1);
    }

    template<typename V, typename W>
    int try_write(std::unique_ptr<char[]> data, unsigned int len, stream_handle<V, W> &send) {
        uv_buf_t bufs[] = {uv_buf_init(data.get(), len)};
        return uv_try_write2(as_uv_stream(), bufs, 1, send.raw());
    }

    int try_write(char *data, unsigned int len) {
        uv_buf_t bufs[] = {uv_buf_init(data, len)};
        return uv_try_write(as_uv_stream(), bufs, 1);
    }

    template<typename V, typename W>
    int try_write(char *data, unsigned int len, stream_handle<V, W> &send) {
        uv_buf_t bufs[] = {uv_buf_init(data, len)};
        return uv_try_write2(as_uv_stream(), bufs, 1, send.raw());
    }

    bool readable() const noexcept {
        return (uv_is_readable(as_uv_stream()) == 1);
    }

    bool writable() const noexcept {
        return (uv_is_writable(as_uv_stream()) == 1);
    }

    bool blocking(bool enable = false) {
        return (0 == uv_stream_set_blocking(as_uv_stream(), enable));
    }

    size_t write_queue_size() const noexcept {
        return uv_stream_get_write_queue_size(as_uv_stream());
    }
};
 
} // namespace uvw
 
#ifndef UVW_AS_LIB
#    include "stream.cpp"
#endif
 
#endif // UVW_STREAM_INCLUDE_H