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.

1 files changed, 41 insertions, 52 deletions

diff --git a/drivers/unix/os_unix.cpp b/drivers/unix/os_unix.cpp
index 75c8a153f6..29fe73f170 100644
--- a/drivers/unix/os_unix.cpp
+++ b/drivers/unix/os_unix.cpp
@@ -64,39 +64,7 @@
 #include <string.h>
 #include <sys/time.h>
 #include <sys/wait.h>
-
-extern bool _print_error_enabled;
-
-void OS_Unix::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 (!_print_error_enabled)
-		return;
-
-	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("\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:
-			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:
-			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:
-			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;
-	}
-}
+#include <unistd.h>
 
 void OS_Unix::debug_break() {
 
@@ -165,29 +133,16 @@ void OS_Unix::initialize_core() {
 	}
 }
 
-void OS_Unix::finalize_core() {
+void OS_Unix::initialize_logger() {
+	Vector<Logger *> loggers;
+	loggers.push_back(memnew(UnixTerminalLogger));
+	loggers.push_back(memnew(RotatedFileLogger("user://logs/log.txt")));
+	_set_logger(memnew(CompositeLogger(loggers)));
 }
 
-void OS_Unix::vprint(const char *p_format, va_list p_list, bool p_stder) {
-
-	if (p_stder) {
-
-		vfprintf(stderr, p_format, p_list);
-		fflush(stderr);
-	} else {
-
-		vprintf(p_format, p_list);
-		fflush(stdout);
-	}
+void OS_Unix::finalize_core() {
 }
 
-void OS_Unix::print(const char *p_format, ...) {
-
-	va_list argp;
-	va_start(argp, p_format);
-	vprintf(p_format, argp);
-	va_end(argp);
-}
 void OS_Unix::alert(const String &p_alert, const String &p_title) {
 
 	fprintf(stderr, "ERROR: %s\n", p_alert.utf8().get_data());
@@ -559,4 +514,38 @@ String OS_Unix::get_executable_path() const {
 #endif
 }
 
+void UnixTerminalLogger::log_error(const char *p_function, const char *p_file, int p_line, const char *p_code, const char *p_rationale, ErrorType p_type) {
+	if (!should_log(true)) {
+		return;
+	}
+
+	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:
+			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:
+			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:
+			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:
+			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;
+	}
+}
+
+UnixTerminalLogger::~UnixTerminalLogger() {}
+
 #endif