stream_server_base.h

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// uvco (c) 2024 Lewin Bormann. See LICENSE for specific terms.
 
#pragma once
 
#include <fmt/core.h>
#include <uv.h>
 
#include "uvco/internal/internal_utils.h"
#include "uvco/promise/multipromise.h"
#include "uvco/promise/promise.h"
 
#include <coroutine>
#include <memory>
#include <optional>
#include <variant>
#include <vector>
 
namespace uvco {
 
 
template <typename UvStreamType> struct UvStreamInitHelper {
  static void init(uv_loop_t * /*loop*/, UvStreamType * /*stream*/) {
    BOOST_ASSERT_MSG(false, "UvStreamInit not specialized for this type");
  }
};
 
template <typename UvStreamType, typename StreamType> class StreamServerBase {
public:
  StreamServerBase(const StreamServerBase &) = delete;
  StreamServerBase(StreamServerBase &&) = default;
  StreamServerBase &operator=(const StreamServerBase &) = delete;
  StreamServerBase &operator=(StreamServerBase &&) = default;
  ~StreamServerBase();
 
  MultiPromise<StreamType> listen(int backlog = 128);
 
  Promise<void> close();
 
protected:
  explicit StreamServerBase(std::unique_ptr<UvStreamType> socket)
      : socket_{std::move(socket)} {}
  std::unique_ptr<UvStreamType> socket_;
 
private:
  static void onNewConnection(uv_stream_t *stream, uv_status status);
 
  struct ConnectionAwaiter_ {
    explicit ConnectionAwaiter_(UvStreamType &socket) : socket_{socket} {
      accepted_.reserve(4);
    }
    [[nodiscard]] bool await_ready() const;
    bool await_suspend(std::coroutine_handle<> handle);
    // Returns true if one or more connections were accepted.
    // Returns false if the listener should stop.
    [[nodiscard]] bool await_resume() const { return !stopped_; }
 
    void stop();
 
    UvStreamType &socket_;
    std::optional<std::coroutine_handle<>> handle_;
 
    // Set of accepted connections or errors.
    using Accepted = std::variant<uv_status, StreamType>;
    std::vector<Accepted> accepted_;
 
    bool stopped_ = false;
  };
};
 
// Implementation contained in stream_server_base_impl.cc, where it's
// instantiated for the currently two socket types using it (UnixServer and
// TcpServer). Include stream_server_base_impl.h to obtain declarations for
// those specializations.
 
 
} // namespace uvco