Addon client: close connection if the player cancels the download

This ensures that the game won't interpret the rest of the addon as a
response for the client's next request.

Fixes #2203.

changelog

@@ -61,6 +61,7 @@ Version 1.13.10+dev:
    * Macro SCEPTRE_OF_FIRE_EFFECT damage increased to 15x4 so Sceptre is an
      improvement over the uncut ruby of fire (14x4) in TRoW.
  * Miscellaneous and bug fixes:
+   * Fixed crash after canceling add-on download (bug #2203)
    * Fixed ingame help showing units you haven't encountered (bug #2135)
    * Fixed the opacity IPF resetting to 0 if the value given was 100% or
      greater (bug #2185).

players_changelog

@@ -24,6 +24,7 @@ Version 1.13.10+dev:
    * Miscellaneous low-level optimizations in game rendering code, improving
      performance ingame by up to 50 %.
  * Miscellaneous and bug fixes:
+   * Fixed crash after canceling add-on download (bug #2203)
    * Fixed ingame help showing units you haven't encountered (bug #2135)
    * Fix recalls updating shroud immediately when "Delay Shroud Updates" is set
      (bug #2196)

src/addon/client.cpp

@@ -43,7 +43,6 @@ addons_client::addons_client(const std::string& address)
 	, host_()
 	, port_()
 	, conn_(nullptr)
-	, stat_(nullptr)
 	, last_error_()
 	, last_error_data_()
 {
@@ -516,40 +515,40 @@ void addons_client::send_simple_request(const std::string& request_string, confi
 }
 struct read_addon_connection_data : public network_transmission::connection_data
 {
-	read_addon_connection_data(network_asio::connection& conn) : conn_(conn) {}
+	read_addon_connection_data(network_asio::connection& conn, addons_client& client)
+		: conn_(conn), client_(client) {}
 	size_t total() override { return conn_.bytes_to_read(); }
 	virtual size_t current()  override { return conn_.bytes_read(); }
 	virtual bool finished() override { return conn_.done(); }
-	virtual void cancel() override { return conn_.cancel(); }
+	virtual void cancel() override { client_.connect(); }
 	virtual void poll() override { conn_.poll(); }
 	network_asio::connection& conn_;
+	addons_client& client_;
 };
 struct write_addon_connection_data : public network_transmission::connection_data
 {
-	write_addon_connection_data(network_asio::connection& conn) : conn_(conn) {}
+	write_addon_connection_data(network_asio::connection& conn, addons_client& client)
+		: conn_(conn), client_(client) {}
 	size_t total() override { return conn_.bytes_to_write(); }
 	virtual size_t current()  override { return conn_.bytes_written(); }
 	virtual bool finished() override { return conn_.done(); }
-	virtual void cancel() override { return conn_.cancel(); }
+	virtual void cancel() override { client_.connect(); }
 	virtual void poll() override { conn_.poll(); }
 	network_asio::connection& conn_;
+	addons_client& client_;
 };
 void addons_client::wait_for_transfer_done(const std::string& status_message, bool track_upload)
 {
 	check_connected();
 	std::unique_ptr<network_transmission::connection_data> cd;
 	if(track_upload)
-		cd.reset(new write_addon_connection_data{ *conn_ });
+		cd.reset(new write_addon_connection_data{*conn_, *this});
 	else
-		cd.reset(new read_addon_connection_data{ *conn_ });
-	if(!stat_) {
-		stat_.reset(new network_transmission(*cd, _("Add-ons Manager"), status_message));
-	} else {
-		stat_->set_subtitle(status_message);
-		stat_->set_connection_data(*cd);
-	}
+		cd.reset(new read_addon_connection_data{*conn_, *this});
 
-	if(!stat_->show()) {
+	gui2::dialogs::network_transmission stat(*cd, _("Add-ons Manager"), status_message);
+
+	if(!stat.show()) {
 		// Notify the caller chain that the user aborted the operation.
 		throw user_exit();
 	}

src/addon/client.hpp

@@ -122,7 +122,6 @@ private:
 	std::string host_;
 	std::string port_;
 	std::unique_ptr<network_asio::connection> conn_;
-	std::unique_ptr<gui2::dialogs::network_transmission> stat_;
 	std::string last_error_;
 	std::string last_error_data_;
 

src/gui/dialogs/network_transmission.cpp

@@ -73,11 +73,6 @@ network_transmission::network_transmission(
 	set_restore(true);
 }
 
-void network_transmission::set_subtitle(const std::string& subtitle)
-{
-	subtitle_ = subtitle;
-}
-
 void network_transmission::pre_show(window& window)
 {
 	// ***** ***** ***** ***** Set up the widgets ***** ***** ***** *****
@@ -94,7 +89,10 @@ void network_transmission::pre_show(window& window)
 void network_transmission::post_show(window& /*window*/)
 {
 	pump_monitor_.window_.reset();
-	connection_->cancel();
+
+	if(get_retval() == window::retval::CANCEL) {
+		connection_->cancel();
+	}
 }
 
 } // namespace dialogs

src/gui/dialogs/network_transmission.hpp

@@ -69,12 +69,6 @@ public:
 						  const std::string& title,
 						  const std::string& subtitle);
 
-	void set_subtitle(const std::string&);
-	void set_connection_data(connection_data& connection)
-	{
-		connection_ = &connection;
-	}
-
 protected:
 	/** Inherited from modal_dialog. */
 	virtual void pre_show(window& window) override;