From bb7793d3093ed1a409c38f096b3543a7af26fcf5 Mon Sep 17 00:00:00 2001
From: Dan Paulat <dpaulat@gmail.com>
Date: Sat, 28 May 2022 14:37:39 -0500
Subject: [PATCH] Use boost::asio for asynchronous processing

---
 scwx-qt/source/scwx/qt/main/main.cpp | 36 ++++++++++++++++++++++++++++
 wxdata/include/scwx/util/threads.hpp |  8 ++++---
 wxdata/source/scwx/util/threads.cpp  | 15 ++++++++++++
 wxdata/wxdata.cmake                  |  1 +
 4 files changed, 57 insertions(+), 3 deletions(-)
 create mode 100644 wxdata/source/scwx/util/threads.cpp

diff --git a/scwx-qt/source/scwx/qt/main/main.cpp b/scwx-qt/source/scwx/qt/main/main.cpp
index 528d2f48..422d464b 100644
--- a/scwx-qt/source/scwx/qt/main/main.cpp
+++ b/scwx-qt/source/scwx/qt/main/main.cpp
@@ -3,30 +3,66 @@
 #include <scwx/qt/manager/resource_manager.hpp>
 #include <scwx/qt/manager/settings_manager.hpp>
 #include <scwx/util/logger.hpp>
+#include <scwx/util/threads.hpp>
 
 #include <aws/core/Aws.h>
+#include <boost/asio.hpp>
 #include <spdlog/spdlog.h>
 #include <QApplication>
 
+static const std::string logPrefix_ = "scwx::main";
+static const auto        logger_    = scwx::util::Logger::Create(logPrefix_);
+
 int main(int argc, char* argv[])
 {
+   // Initialize logger
    scwx::util::Logger::Initialize();
    spdlog::set_level(spdlog::level::debug);
 
    QCoreApplication::setApplicationName("Supercell Wx");
 
+   // Start the io_context main loop
+   boost::asio::io_context& ioContext = scwx::util::io_context();
+   auto                     work      = boost::asio::make_work_guard(ioContext);
+   boost::asio::thread_pool threadPool {4};
+   boost::asio::post(threadPool,
+                     [&]()
+                     {
+                        while (true)
+                        {
+                           try
+                           {
+                              ioContext.run();
+                              break; // run() exited normally
+                           }
+                           catch (std::exception& ex)
+                           {
+                              // Log exception and continue
+                              logger_->error(ex.what());
+                           }
+                        }
+                     });
+
+   // Initialize AWS SDK
    Aws::SDKOptions awsSdkOptions;
    Aws::InitAPI(awsSdkOptions);
 
+   // Initialize application
    scwx::qt::config::RadarSite::Initialize();
    scwx::qt::manager::SettingsManager::Initialize();
    scwx::qt::manager::ResourceManager::PreLoad();
 
+   // Run Qt main loop
    QApplication               a(argc, argv);
    scwx::qt::main::MainWindow w;
    w.show();
    int result = a.exec();
 
+   // Gracefully stop the io_context main loop
+   work.reset();
+   threadPool.join();
+
+   // Shutdown AWS SDK
    Aws::ShutdownAPI(awsSdkOptions);
 
    return result;
diff --git a/wxdata/include/scwx/util/threads.hpp b/wxdata/include/scwx/util/threads.hpp
index ef0a5cb0..441105b6 100644
--- a/wxdata/include/scwx/util/threads.hpp
+++ b/wxdata/include/scwx/util/threads.hpp
@@ -1,15 +1,17 @@
-#include <future>
+#include <boost/asio/io_context.hpp>
+#include <boost/asio/post.hpp>
 
 namespace scwx
 {
 namespace util
 {
 
+boost::asio::io_context& io_context();
+
 template<class F>
 void async(F&& f)
 {
-   auto future = std::make_shared<std::future<void>>();
-   *future     = std::async(std::launch::async, [future, f]() { f(); });
+   boost::asio::post(io_context(), f);
 }
 
 } // namespace util
diff --git a/wxdata/source/scwx/util/threads.cpp b/wxdata/source/scwx/util/threads.cpp
new file mode 100644
index 00000000..2b179c36
--- /dev/null
+++ b/wxdata/source/scwx/util/threads.cpp
@@ -0,0 +1,15 @@
+#include <scwx/util/threads.hpp>
+
+namespace scwx
+{
+namespace util
+{
+
+boost::asio::io_context& io_context()
+{
+   static boost::asio::io_context ioContext {};
+   return ioContext;
+}
+
+} // namespace util
+} // namespace scwx
diff --git a/wxdata/wxdata.cmake b/wxdata/wxdata.cmake
index 50a40872..ee41fba6 100644
--- a/wxdata/wxdata.cmake
+++ b/wxdata/wxdata.cmake
@@ -54,6 +54,7 @@ set(SRC_UTIL source/scwx/util/float.cpp
              source/scwx/util/rangebuf.cpp
              source/scwx/util/streams.cpp
              source/scwx/util/time.cpp
+             source/scwx/util/threads.cpp
              source/scwx/util/vectorbuf.cpp)
 set(HDR_WSR88D include/scwx/wsr88d/ar2v_file.hpp
                include/scwx/wsr88d/level3_file.hpp