Add asio standalone example (#133)

* Add asio standalone example * Mark VERSION explicitly Without this version information, CPM's versioning mechanism may break in some cases. Also add comments for compile definition on Windows. * Use aync-tcp-echo-server as the example * Add boost software license to the demo source Co-authored-by: Lars Melchior <TheLartians@users.noreply.github.com> Co-authored-by: Lars Melchior <TheLartians@users.noreply.github.com>
2025-11-25 05:37:28 -05:00 · 2020-06-24 18:40:12 +08:00
parent 9ec279c75f
commit f8afae6eb3
2 changed files with 197 additions and 0 deletions
--- a/examples/asio-standalone/CMakeLists.txt
+++ b/examples/asio-standalone/CMakeLists.txt
@@ -0,0 +1,79 @@
+cmake_minimum_required(VERSION 3.14 FATAL_ERROR)
+
+project(CPMExampleASIOStandalone)
+
+# ---- Dependencies ----
+
+include(../../cmake/CPM.cmake)
+
+find_package(Threads REQUIRED)
+
+CPMAddPackage(
+  NAME asio
+  VERSION 1.16.1
+  GITHUB_REPOSITORY chriskohlhoff/asio
+  GIT_TAG asio-1-16-1   # asio uses non-standard version tag, we must specify GIT_TAG
+)
+
+# ASIO doesn't use CMake, we have to configure it manually.
+# Extra notes for using on Windows:
+# 1) If _WIN32_WINNT is not set, ASIO assumes _WIN32_WINNT=0x0501, i.e. Windows XP target,
+# which is definitely not the platform which most users target.
+# 2) WIN32_LEAN_AND_MEAN is defined to make Winsock2 work.
+if(asio_ADDED)
+  add_library(asio INTERFACE)
+
+  target_include_directories(asio
+    INTERFACE ${asio_SOURCE_DIR}/asio/include
+  )
+
+  target_compile_definitions(asio
+    INTERFACE
+      ASIO_STANDALONE
+      ASIO_NO_DEPRECATED
+  )
+
+  target_link_libraries(asio
+    INTERFACE
+      Threads::Threads
+  )
+
+  if(WIN32)
+    # macro see @ https://stackoverflow.com/a/40217291/1746503
+    macro(get_win32_winnt version)
+      if (CMAKE_SYSTEM_VERSION)
+        set(ver ${CMAKE_SYSTEM_VERSION})
+        string(REGEX MATCH "^([0-9]+).([0-9])" ver ${ver})
+        string(REGEX MATCH "^([0-9]+)" verMajor ${ver})
+        # Check for Windows 10, b/c we'll need to convert to hex 'A'.
+        if ("${verMajor}" MATCHES "10")
+          set(verMajor "A")
+          string(REGEX REPLACE "^([0-9]+)" ${verMajor} ver ${ver})
+        endif ("${verMajor}" MATCHES "10")
+        # Remove all remaining '.' characters.
+        string(REPLACE "." "" ver ${ver})
+        # Prepend each digit with a zero.
+        string(REGEX REPLACE "([0-9A-Z])" "0\\1" ver ${ver})
+        set(${version} "0x${ver}")
+      endif()
+    endmacro()
+
+    if(NOT DEFINED _WIN32_WINNT)
+      get_win32_winnt(ver)
+      set(_WIN32_WINNT ${ver})
+    endif()
+
+    message(STATUS "Set _WIN32_WINNET=${_WIN32_WINNT}")
+
+    target_compile_definitions(asio
+      INTERFACE
+        _WIN32_WINNT=${_WIN32_WINNT}
+        WIN32_LEAN_AND_MEAN
+    )
+  endif()
+endif()
+
+# ---- Executable ----
+
+add_executable(CPMExampleASIOStandalone main.cpp)
+target_link_libraries(CPMExampleASIOStandalone asio)
--- a/examples/asio-standalone/main.cpp
+++ b/examples/asio-standalone/main.cpp
@@ -0,0 +1,118 @@
+//
+// async_tcp_echo_server.cpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2020 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+#include <utility>
+
+#include "asio.hpp"
+
+// An asynchronous tcp echo server.
+// See https://think-async.com/Asio/asio-1.16.1/src/examples/cpp11/echo/async_tcp_echo_server.cpp
+
+using asio::ip::tcp;
+
+class session
+  : public std::enable_shared_from_this<session>
+{
+public:
+  session(tcp::socket socket)
+    : socket_(std::move(socket))
+  {
+  }
+
+  void start()
+  {
+    do_read();
+  }
+
+private:
+  void do_read()
+  {
+    auto self(shared_from_this());
+    socket_.async_read_some(asio::buffer(data_, max_length),
+        [this, self](std::error_code ec, std::size_t length)
+        {
+          if (!ec)
+          {
+            do_write(length);
+          }
+        });
+  }
+
+  void do_write(std::size_t length)
+  {
+    auto self(shared_from_this());
+    asio::async_write(socket_, asio::buffer(data_, length),
+        [this, self](std::error_code ec, std::size_t /*length*/)
+        {
+          if (!ec)
+          {
+            do_read();
+          }
+        });
+  }
+
+  tcp::socket socket_;
+  enum { max_length = 1024 };
+  char data_[max_length];
+};
+
+class server
+{
+public:
+  server(asio::io_context& io_context, short port)
+    : acceptor_(io_context, tcp::endpoint(tcp::v4(), port))
+  {
+    do_accept();
+  }
+
+private:
+  void do_accept()
+  {
+    acceptor_.async_accept(
+        [this](std::error_code ec, tcp::socket socket)
+        {
+          if (!ec)
+          {
+            std::make_shared<session>(std::move(socket))->start();
+          }
+
+          do_accept();
+        });
+  }
+
+  tcp::acceptor acceptor_;
+};
+
+int main(int argc, char* argv[])
+{
+  try
+  {
+    if (argc != 2)
+    {
+      std::cerr << "Usage: async_tcp_echo_server <port>\n";
+      return 1;
+    }
+
+    asio::io_context io_context;
+
+    server s(io_context, std::atoi(argv[1]));
+
+    io_context.run();
+  }
+  catch (std::exception& e)
+  {
+    std::cerr << "Exception: " << e.what() << "\n";
+  }
+
+  return 0;
+}