Use a shared string for example HTTP server doc roots

fix #1109

example/http/server/coro-ssl/http_server_coro_ssl.cpp

@@ -256,7 +256,7 @@ void
 do_session(
     tcp::socket& socket,
     ssl::context& ctx,
-    std::string const& doc_root,
+    std::shared_ptr<std::string const> const& doc_root,
     boost::asio::yield_context yield)
 {
     bool close = false;
@@ -287,7 +287,7 @@ do_session(
             return fail(ec, "read");
 
         // Send the response
-        handle_request(doc_root, std::move(req), lambda);
+        handle_request(*doc_root, std::move(req), lambda);
         if(ec)
             return fail(ec, "write");
         if(close)
@@ -314,7 +314,7 @@ do_listen(
     boost::asio::io_context& ioc,
     ssl::context& ctx,
     tcp::endpoint endpoint,
-    std::string const& doc_root,
+    std::shared_ptr<std::string const> const& doc_root,
     boost::asio::yield_context yield)
 {
     boost::system::error_code ec;
@@ -371,7 +371,7 @@ int main(int argc, char* argv[])
     }
     auto const address = boost::asio::ip::make_address(argv[1]);
     auto const port = static_cast<unsigned short>(std::atoi(argv[2]));
-    std::string const doc_root = argv[3];
+    auto const doc_root = std::make_shared<std::string>(argv[3]);
     auto const threads = std::max<int>(1, std::atoi(argv[4]));
 
     // The io_context is required for all I/O