From 3d43918dc24a89bccac1b52e92acf1e2b120bcf0 Mon Sep 17 00:00:00 2001
From: Florian Fischer <florian.fl.fischer@fau.de>
Date: Thu, 4 Feb 2021 18:48:50 +0100
Subject: [PATCH] Add callback based EchoServer implementation
---
apps/EchoServerCallback.cpp | 118 ++++++++++++++++++++++++++++++++++++
apps/meson.build | 6 ++
2 files changed, 124 insertions(+)
create mode 100644 apps/EchoServerCallback.cpp
diff --git a/apps/EchoServerCallback.cpp b/apps/EchoServerCallback.cpp
new file mode 100644
index 00000000..b6b6a29e
--- /dev/null
+++ b/apps/EchoServerCallback.cpp
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: LGPL-3.0-or-later
+// Copyright © 2020-2021 Florian Fischer
+#include <sys/socket.h>
+
+#include <array>
+#include <cerrno>
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+
+#include "Common.hpp"
+#include "Debug.hpp"
+#include "Runtime.hpp"
+#include "io.hpp"
+#include "io/Future.hpp"
+
+using SendFuture = emper::io::SendFuture;
+using RecvFuture = emper::io::RecvFuture;
+
+const std::string HOST = "::";
+const std::string PORT = "12345";
+
+const size_t BUF_SIZE = 1024;
+
+class Client {
+ public:
+ int sockfd;
+ size_t bytes_recv;
+ size_t bytes_send;
+ std::array<char, BUF_SIZE> buf;
+
+ Client(int socket) : sockfd(socket), bytes_recv(0), bytes_send(0) {}
+
+ void submitSend() {
+ SendFuture sf(sockfd, &buf[bytes_send], bytes_recv - bytes_send, MSG_NOSIGNAL);
+ sf.setCallback([this](int32_t bytes_send) { this->onSend(bytes_send); });
+ sf.submit();
+ }
+
+ void onSend(int32_t res) {
+ if (unlikely(res < 0)) {
+ LOGE("server send failed: " << strerror(errno));
+ emper::io::closeAndForget(sockfd);
+ return;
+ }
+
+ bytes_send += res;
+
+ // Send again
+ if (bytes_send < bytes_recv) {
+ submitSend();
+ return;
+ }
+
+ submitRecv();
+ }
+
+ void submitRecv() {
+ bytes_send = 0;
+ RecvFuture rf(sockfd, buf.data(), BUF_SIZE, 0);
+ rf.setCallback([this](int32_t bytes_recv) { this->onRecv(bytes_recv); });
+ rf.submit();
+ }
+
+ void onRecv(int32_t res) {
+ if (unlikely(res <= 0)) {
+ // socket was shutdown
+ if (res < 0) {
+ LOGE("server read failed:" << strerror(errno));
+ }
+
+ emper::io::closeAndForget(sockfd);
+ return;
+ }
+
+ bytes_recv = res;
+
+ if (unlikely(bytes_recv == 5 && strncmp("quit\n", buf.data(), bytes_recv) == 0)) {
+ exit(EXIT_SUCCESS);
+ }
+
+ submitSend();
+ }
+};
+
+auto main(int argc, char* argv[]) -> int {
+ std::string host = HOST;
+ std::string port = PORT;
+
+ if (argc > 2) {
+ std::cerr << "Usage: " << argv[0] << " [port]" << std::endl;
+ exit(EXIT_FAILURE);
+ }
+
+ if (argc > 1) {
+ port = std::string(argv[1]);
+ }
+
+ std::cout << "Echoserver listening on " << host << ":" << port << std::endl;
+
+ Runtime runtime;
+ auto* listener = emper::io::tcp_listener(host, port, [](int socket) {
+ auto* client = new Client(socket);
+ client->submitRecv();
+ });
+
+ if (!listener) {
+ exit(EXIT_FAILURE);
+ }
+
+ runtime.scheduleFromAnywhere(*listener);
+
+ runtime.waitUntilFinished();
+
+ return EXIT_FAILURE;
+}
diff --git a/apps/meson.build b/apps/meson.build
index 015a15df..44ff1edb 100644
--- a/apps/meson.build
+++ b/apps/meson.build
@@ -16,6 +16,12 @@ echoserver_exe = executable(
dependencies: emper_dep,
)
+echoserver_callback_exe = executable(
+ 'echoserver_callback',
+ 'EchoServerCallback.cpp',
+ dependencies: emper_dep,
+)
+
echoclient_exe = executable(
'echoclient',
'EchoClient.cpp',
--
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