Crafter.Network/interfaces/Crafter.Network-ClientTCP.cppm

//SPDX-License-Identifier: LGPL-3.0-only
//SPDX-FileCopyrightText: Copyright (C) 2026 Catcrafts®

module;
#ifndef CRAFTER_NETWORK_BROWSER
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <sys/uio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/ioctl.h>
#include <netdb.h>
#include <strings.h>
#include <cerrno>
#endif
export module Crafter.Network:ClientTCP;
import std;

#ifndef CRAFTER_NETWORK_BROWSER
namespace Crafter {
	export class SocketClosedException : public std::exception {
	public:
	const char* what() const noexcept override {
		return "Socket closed";
	}
};

	// A connect or a receive waited longer than its timeout.
	export class SocketTimeoutException : public std::exception {
	public:
	const char* what() const noexcept override {
		return "Socket timed out";
	}
};

	// The step of a connection a SocketErrorException failed at.
	export enum class SocketPhase {
		// getaddrinfo on the host name.
		Resolve,
		// socket() for an address the host resolved to.
		Open,
		// connect() to that address.
		Connect,
		Send,
		Receive,
	};

	// The error category of getaddrinfo's results (EAI_NONAME, EAI_AGAIN,
	// ...): a number space of its own that overlaps the errno values, so a
	// resolver code is never confused with an errno, and whose message() is
	// gai_strerror's text. One instance for the process, like
	// std::generic_category().
	export const std::error_category& ResolverCategory() noexcept;

	// A resolve, a socket(), a connect, a send or a receive that failed. A
	// std::system_error, so still a std::runtime_error for the handlers that
	// catch one: code() is the errno under std::generic_category(), or the
	// getaddrinfo result under ResolverCategory(), and what() is the text
	// ClientTCP has always thrown, the code's own text after it. `phase`
	// says which step failed. A caller that reports the cause in its own
	// words — "[Errno 111] Connection refused", say — takes code().value()
	// and code().message() instead of parsing what(), and compares code()
	// with std::errc::connection_refused instead of the number.
	export class SocketErrorException : public std::system_error {
	public:
		SocketErrorException(SocketPhase phase, std::error_code code, const std::string& what)
			: std::system_error(code, what), phase(phase) {}
		// Without a message of its own: what() is the code's text alone.
		SocketErrorException(SocketPhase phase, std::error_code code)
			: std::system_error(code), phase(phase) {}
		SocketPhase phase;
	};

	export class ClientTCP {
	public:
		int socketid;
        ClientTCP(int socket);
        // The host is resolved for IPv4 and IPv6 alike and every address it
        // resolves to is tried in turn, the way Python's
        // socket.create_connection does: `localhost` reaches a server that
        // listens on ::1 only, as a dev server on a recent Node does. The
        // first address that connects wins; when none does, what the last
        // one failed with is thrown — SocketErrorException, or
        // SocketTimeoutException for a timeout.
        //
        // A non-zero connectTimeout makes a connect nobody answers throw
        // SocketTimeoutException after that long, where it would otherwise
        // wait out the kernel's retries, about two minutes. It bounds each
        // address on its own. A refused connect fails at once either way.
        ClientTCP(const char* host, std::uint16_t port, std::chrono::milliseconds connectTimeout = std::chrono::milliseconds::zero());
		ClientTCP(std::string host, std::uint16_t port, std::chrono::milliseconds connectTimeout = std::chrono::milliseconds::zero());
        ~ClientTCP();
		ClientTCP(const ClientTCP&) = delete;
		ClientTCP(ClientTCP&& other) noexcept;
		void Connect(std::chrono::milliseconds timeout = std::chrono::milliseconds::zero());
		void Stop();
		// Turns Nagle's algorithm off (TCP_NODELAY), so a small write goes
		// out at once instead of waiting for the ACK of the one before it.
		// For small messages that must arrive promptly, such as a stream of
		// frames.
		void SetNoDelay(bool enabled);
		// A receive that waits longer than this throws
		// SocketTimeoutException, losing what a whole-buffer receive had read
		// so far. Zero, the default, waits for good.
		void SetReceiveTimeout(std::chrono::milliseconds timeout);
		void Send(const void* buffer, std::uint32_t size) const;
		// The receives return what arrived, at least one byte; asked for none,
		// none, at once, without looking at the socket. They throw
		// SocketClosedException once the peer has closed, and
		// SocketTimeoutException when a receive timeout runs out.
		std::vector<char> RecieveSync() const;
		std::vector<char> RecieveUntilCloseSync() const;
		std::vector<char> RecieveUntilFullSync(std::uint32_t bufferSize) const;
		std::vector<char> RecieveSync(std::uint32_t bufferSize) const;
		// Into `buffer`; returns how many bytes it put there.
        std::uint32_t RecieveSync(std::uint32_t bufferSize, void* buffer) const;
		// The same receives on Crafter.Thread's ThreadPool. What arrived goes
		// to the callback; what a receive throws goes to onError instead (an
		// empty one drops it), as an exception left to escape a pool task
		// would end the program.
		void RecieveAsync(std::function<void(std::vector<char>)> recieveCallback, std::function<void(std::exception_ptr)> onError) const;
		void RecieveUntilCloseAsync(std::function<void(std::vector<char>)> recieveCallback, std::function<void(std::exception_ptr)> onError) const;
        void RecieveAsync(std::uint32_t bufferSize, std::function<void(std::vector<char>)> recieveCallback, std::function<void(std::exception_ptr)> onError) const;
		void RecieveUntilFullAsync(std::uint32_t bufferSize, std::function<void(std::vector<char>)> recieveCallback, std::function<void(std::exception_ptr)> onError) const;
		// Into `buffer`, which must outlive the receive; the callback gets the count.
        void RecieveAsync(std::uint32_t bufferSize, std::function<void(std::uint32_t)> recieveCallback, char* buffer, std::function<void(std::exception_ptr)> onError) const;
	private:
		struct Address {
			sockaddr_storage storage;
			socklen_t length;
		};
		// What the host resolved to, in getaddrinfo's order; empty for a
		// socket handed over by accept().
		std::vector<Address> addresses;
	};
}
#endif