Extract logging logic

Previously logging logic was scattered over OS class implementations
with plenty of duplication. Major changes in this commit:

 - Extracted logging logic into a separate Logger hierarchy. It allows
   easy configuration of logging mechanism depending on compile-time or
   run-time configuration.

 - Implemented RotatedFileLogger which is usually used with StdLogger,
   providing persistency of logs. It is often important to be able to
   obtain logs of the game even in production to be able to understand
   what happened prior to some problem. On mobile there previously was
   no way to obtain the logs aside from having the device connected to
   your machine.

 - flush() is not performed in release mode for every logged line. It
   is only performed for errors.

2 files changed, 11 insertions, 53 deletions

diff --git a/platform/uwp/os_uwp.cpp b/platform/uwp/os_uwp.cpp
index b909ccccd6..031c714514 100644
--- a/platform/uwp/os_uwp.cpp
+++ b/platform/uwp/os_uwp.cpp
@@ -40,6 +40,7 @@
 #include "platform/windows/packet_peer_udp_winsock.h"
 #include "platform/windows/stream_peer_winsock.h"
 #include "platform/windows/tcp_server_winsock.h"
+#include "platform/windows/windows_terminal_logger.h"
 #include "project_settings.h"
 #include "servers/audio_server.h"
 #include "servers/visual/visual_server_raster.h"
@@ -182,6 +183,13 @@ void OSUWP::initialize_core() {
 	cursor_shape = CURSOR_ARROW;
 }
 
+void OSUWP::initialize_logger() {
+	Vector<Logger *> loggers;
+	loggers.push_back(memnew(WindowsTerminalLogger));
+	loggers.push_back(memnew(RotatedFileLogger("user://logs/log.txt")));
+	_set_logger(memnew(CompositeLogger(loggers)));
+}
+
 bool OSUWP::can_draw() const {
 
 	return !minimized;
@@ -371,32 +379,6 @@ void OSUWP::finalize() {
 void OSUWP::finalize_core() {
 }
 
-void OSUWP::vprint(const char *p_format, va_list p_list, bool p_stderr) {
-
-	char buf[16384 + 1];
-	int len = vsnprintf(buf, 16384, p_format, p_list);
-	if (len <= 0)
-		return;
-	buf[len] = 0;
-
-	int wlen = MultiByteToWideChar(CP_UTF8, 0, buf, len, NULL, 0);
-	if (wlen < 0)
-		return;
-
-	wchar_t *wbuf = (wchar_t *)malloc((len + 1) * sizeof(wchar_t));
-	MultiByteToWideChar(CP_UTF8, 0, buf, len, wbuf, wlen);
-	wbuf[wlen] = 0;
-
-	if (p_stderr)
-		fwprintf(stderr, L"%s", wbuf);
-	else
-		wprintf(L"%s", wbuf);
-
-	free(wbuf);
-
-	fflush(stdout);
-};
-
 void OSUWP::alert(const String &p_alert, const String &p_title) {
 
 	Platform::String ^ alert = ref new Platform::String(p_alert.c_str());
@@ -520,30 +502,6 @@ OS::VideoMode OSUWP::get_video_mode(int p_screen) const {
 void OSUWP::get_fullscreen_mode_list(List<VideoMode> *p_list, int p_screen) const {
 }
 
-void OSUWP::print_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type) {
-
-	const char *err_details;
-	if (p_rationale && p_rationale[0])
-		err_details = p_rationale;
-	else
-		err_details = p_code;
-
-	switch (p_type) {
-		case ERR_ERROR:
-			print("ERROR: %s: %s\n", p_function, err_details);
-			print("   At: %s:%i\n", p_file, p_line);
-			break;
-		case ERR_WARNING:
-			print("WARNING: %s: %s\n", p_function, err_details);
-			print("     At: %s:%i\n", p_file, p_line);
-			break;
-		case ERR_SCRIPT:
-			print("SCRIPT ERROR: %s: %s\n", p_function, err_details);
-			print("          At: %s:%i\n", p_file, p_line);
-			break;
-	}
-}
-
 String OSUWP::get_name() {
 
 	return "UWP";
@@ -890,6 +848,8 @@ OSUWP::OSUWP() {
 	mouse_mode_changed = CreateEvent(NULL, TRUE, FALSE, L"os_mouse_mode_changed");
 
 	AudioDriverManager::add_driver(&audio_driver);
+
+	_set_logger(memnew(WindowsTerminalLogger));
 }
 
 OSUWP::~OSUWP() {
diff --git a/platform/uwp/os_uwp.h b/platform/uwp/os_uwp.h
index a7a5d32cb9..df38faa8e1 100644
--- a/platform/uwp/os_uwp.h
+++ b/platform/uwp/os_uwp.h
@@ -163,6 +163,7 @@ protected:
 	virtual int get_audio_driver_count() const;
 	virtual const char *get_audio_driver_name(int p_driver) const;
 
+	virtual void initialize_logger();
 	virtual void initialize_core();
 	virtual void initialize(const VideoMode &p_desired, int p_video_driver, int p_audio_driver);
 
@@ -180,9 +181,6 @@ public:
 	// Event to send to the app wrapper
 	HANDLE mouse_mode_changed;
 
-	void print_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type);
-
-	virtual void vprint(const char *p_format, va_list p_list, bool p_stderr = false);
 	virtual void alert(const String &p_alert, const String &p_title = "ALERT!");
 	String get_stdin_string(bool p_block);