From 90bd600c5025ede4db99122f13dfb07b27de46ae Mon Sep 17 00:00:00 2001
From: Egor Tensin <Egor.Tensin@gmail.com>
Date: Sat, 30 Nov 2019 01:38:08 +0300
Subject: initial commit

---
 server/session.cpp | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 server/session.cpp

(limited to 'server/session.cpp')

diff --git a/server/session.cpp b/server/session.cpp
new file mode 100644
index 0000000..409ca5a
--- /dev/null
+++ b/server/session.cpp
@@ -0,0 +1,113 @@
+#include "error.hpp"
+#include "log.hpp"
+#include "parser.hpp"
+#include "session.hpp"
+#include "session_manager.hpp"
+
+#include <boost/asio.hpp>
+#include <boost/lexical_cast.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/system/system_error.hpp>
+
+#include <cstddef>
+
+#include <exception>
+#include <string>
+#include <utility>
+
+namespace math::server {
+namespace {
+
+std::string reply_to_string(double result) {
+    return boost::lexical_cast<std::string>(result);
+}
+
+std::string calc_reply(const std::string& input) {
+    std::string reply;
+    try {
+        reply = reply_to_string(Parser{input}.exec());
+    } catch (const std::exception& e) {
+        reply = e.what();
+    }
+    return reply;
+}
+
+}
+
+Session::Session(SessionManager& mgr, boost::asio::io_context& io_context)
+    : m_session_mgr{mgr}, m_strand{io_context}, m_socket{io_context}
+{ }
+
+boost::asio::ip::tcp::socket& Session::socket() {
+    return m_socket;
+}
+
+void Session::start() {
+    read();
+}
+
+void Session::stop() {
+    close();
+}
+
+void Session::close() {
+    try {
+        m_socket.shutdown(boost::asio::ip::tcp::socket::shutdown_both);
+        m_socket.close();
+    } catch (const boost::system::system_error& e) {
+        throw Error{e.what()};
+    }
+}
+
+void Session::read() {
+    const auto self = shared_from_this();
+
+    // Stop at LF
+    boost::asio::async_read_until(m_socket, m_buffer, '\n', boost::asio::bind_executor(m_strand,
+        [this, self] (const boost::system::error_code& ec, std::size_t bytes) {
+            handle_read(ec, bytes);
+        }));
+}
+
+void Session::handle_read(const boost::system::error_code& ec, std::size_t bytes) {
+    if (ec) {
+        log::error("%1%: %2%", __func__, ec.message());
+        m_session_mgr.stop(shared_from_this());
+        return;
+    }
+
+    write(calc_reply(consume_input(bytes)));
+}
+
+std::string Session::consume_input(std::size_t bytes) {
+    const auto data = boost::asio::buffer_cast<const char*>(m_buffer.data());
+    const std::string input{data, bytes - 1};
+    m_buffer.consume(bytes);
+    return input;
+}
+
+void Session::write(std::string output) {
+    const auto self = shared_from_this();
+
+    // Include CR (so that Windows' telnet client works)
+    output += "\r\n";
+
+    boost::asio::const_buffer buffer{output.c_str(), output.length()};
+
+    boost::asio::async_write(m_socket, std::move(buffer), boost::asio::bind_executor(m_strand,
+        [this, self] (const boost::system::error_code& ec, std::size_t bytes) {
+            handle_write(ec, bytes);
+        }));
+}
+
+void Session::handle_write(const boost::system::error_code& ec, std::size_t bytes) {
+    if (ec) {
+        log::error("%1%: %2%", __func__, ec.message());
+        m_session_mgr.stop(shared_from_this());
+        return;
+    }
+
+    read();
+}
+
+}
-- 
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