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, 59 insertions, 34 deletions

diff --git a/platform/osx/os_osx.h b/platform/osx/os_osx.h
index 6c81da04f5..ed67107e9e 100644
--- a/platform/osx/os_osx.h
+++ b/platform/osx/os_osx.h
@@ -129,6 +129,7 @@ protected:
 	virtual const char *get_video_driver_name(int p_driver) const;
 	virtual VideoMode get_default_video_mode() const;
 
+	virtual void initialize_logger();
 	virtual void initialize_core();
 	virtual void initialize(const VideoMode &p_desired, int p_video_driver, int p_audio_driver);
 	virtual void finalize();
@@ -143,8 +144,6 @@ public:
 
 	virtual String get_name();
 
-	virtual 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 = ERR_ERROR);
-
 	virtual void alert(const String &p_alert, const String &p_title = "ALERT!");
 
 	virtual void set_cursor_shape(CursorShape p_shape);
diff --git a/platform/osx/os_osx.mm b/platform/osx/os_osx.mm
index 9a26adc155..e4f6ca1a34 100644
--- a/platform/osx/os_osx.mm
+++ b/platform/osx/os_osx.mm
@@ -1145,43 +1145,67 @@ String OS_OSX::get_name() {
 	return "OSX";
 }
 
-void OS_OSX::print_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type) {
-
 #if MAC_OS_X_VERSION_MAX_ALLOWED >= 101200
-	if (!_print_error_enabled)
-		return;
-
-	const char *err_details;
-	if (p_rationale && p_rationale[0])
-		err_details = p_rationale;
-	else
-		err_details = p_code;
+class OSXTerminalLogger : public StdLogger {
+public:
+	virtual void log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type = ERR_ERROR) {
+		if (!should_log(true)) {
+			return;
+		}
 
-	switch (p_type) {
-		case ERR_ERROR:
-			os_log_error(OS_LOG_DEFAULT, "ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.", p_function, err_details, p_file, p_line);
-			print("\E[1;31mERROR: %s: \E[0m\E[1m%s\n", p_function, err_details);
-			print("\E[0;31m   At: %s:%i.\E[0m\n", p_file, p_line);
-			break;
-		case ERR_WARNING:
-			os_log_info(OS_LOG_DEFAULT, "WARNING: %{public}s: %{public}s\nAt: %{public}s:%i.", p_function, err_details, p_file, p_line);
-			print("\E[1;33mWARNING: %s: \E[0m\E[1m%s\n", p_function, err_details);
-			print("\E[0;33m   At: %s:%i.\E[0m\n", p_file, p_line);
-			break;
-		case ERR_SCRIPT:
-			os_log_error(OS_LOG_DEFAULT, "SCRIPT ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.", p_function, err_details, p_file, p_line);
-			print("\E[1;35mSCRIPT ERROR: %s: \E[0m\E[1m%s\n", p_function, err_details);
-			print("\E[0;35m   At: %s:%i.\E[0m\n", p_file, p_line);
-			break;
-		case ERR_SHADER:
-			os_log_error(OS_LOG_DEFAULT, "SHADER ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.", p_function, err_details, p_file, p_line);
-			print("\E[1;36mSHADER ERROR: %s: \E[0m\E[1m%s\n", p_function, err_details);
-			print("\E[0;36m   At: %s:%i.\E[0m\n", p_file, p_line);
-			break;
+		const char *err_details;
+		if (p_rationale && p_rationale[0])
+			err_details = p_rationale;
+		else
+			err_details = p_code;
+
+		switch (p_type) {
+			case ERR_WARNING:
+				os_log_info(OS_LOG_DEFAULT,
+						"WARNING: %{public}s: %{public}s\nAt: %{public}s:%i.",
+						p_function, err_details, p_file, p_line);
+				logf_error("\E[1;33mWARNING: %s: \E[0m\E[1m%s\n", p_function,
+						err_details);
+				logf_error("\E[0;33m   At: %s:%i.\E[0m\n", p_file, p_line);
+				break;
+			case ERR_SCRIPT:
+				os_log_error(OS_LOG_DEFAULT,
+						"SCRIPT ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.",
+						p_function, err_details, p_file, p_line);
+				logf_error("\E[1;35mSCRIPT ERROR: %s: \E[0m\E[1m%s\n", p_function,
+						err_details);
+				logf_error("\E[0;35m   At: %s:%i.\E[0m\n", p_file, p_line);
+				break;
+			case ERR_SHADER:
+				os_log_error(OS_LOG_DEFAULT,
+						"SHADER ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.",
+						p_function, err_details, p_file, p_line);
+				logf_error("\E[1;36mSHADER ERROR: %s: \E[0m\E[1m%s\n", p_function,
+						err_details);
+				logf_error("\E[0;36m   At: %s:%i.\E[0m\n", p_file, p_line);
+				break;
+			case ERR_ERROR:
+			default:
+				os_log_error(OS_LOG_DEFAULT,
+						"ERROR: %{public}s: %{public}s\nAt: %{public}s:%i.",
+						p_function, err_details, p_file, p_line);
+				logf_error("\E[1;31mERROR: %s: \E[0m\E[1m%s\n", p_function, err_details);
+				logf_error("\E[0;31m   At: %s:%i.\E[0m\n", p_file, p_line);
+				break;
+		}
 	}
+};
+
 #else
-	OS_Unix::print_error(p_function, p_file, p_line, p_code, p_rationale, p_type);
+
+typedef UnixTerminalLogger OSXTerminalLogger;
 #endif
+
+void OS_OSX::initialize_logger() {
+	Vector<Logger *> loggers;
+	loggers.push_back(memnew(OSXTerminalLogger));
+	loggers.push_back(memnew(RotatedFileLogger("user://logs/log.txt")));
+	_set_logger(memnew(CompositeLogger(loggers)));
 }
 
 void OS_OSX::alert(const String &p_alert, const String &p_title) {
@@ -2003,6 +2027,8 @@ OS_OSX::OS_OSX() {
 	window_size = Vector2(1024, 600);
 	zoomed = false;
 	display_scale = 1.0;
+
+	_set_logger(memnew(OSXTerminalLogger));
 }
 
 bool OS_OSX::_check_internal_feature_support(const String &p_feature) {