add LogFlush config var for instant writes (disabled as default) (#2796)

 - remove deprecated LogSubsystems config var
 - config descriptions

doc/changelog.txt

@@ -17,6 +17,8 @@ Changes:
  ! remove selectkeys.txt support (use uikeys.txt instead)
  ! remove TASServer.jar (outdated, use http://springrts.com/wiki/Spring_on_a_LAN )
  ! send gameID and SDF filename with SERVER_STARTPLAYING to autohost
+ ! remove deprecated LogSubsystems config var
+ - add LogFlush config var for instant writes (disabled as default)
 
 Bugfixes:
  - dedicated server no longer consumes 100% CPU while waiting for gameID

rts/System/Log/FileSink.cpp

@@ -20,10 +20,11 @@ namespace {
 
 	struct LogFileDetails {
 		LogFileDetails(FILE* outStream = NULL, const std::string& sections = "",
-				int minLevel = LOG_LEVEL_ALL)
+				int minLevel = LOG_LEVEL_ALL, bool flush = true)
 			: outStream(outStream)
 			, sections(sections)
 			, minLevel(minLevel)
+			, flush(flush)
 		{}
 
 		FILE* GetOutStream() const {
@@ -35,11 +36,15 @@ namespace {
 					|| (sections.find("," + std::string(section) + ",")
 					!= std::string::npos)));
 		}
+		bool IsFlush() const{
+			return flush;
+		}
 
 	private:
 		FILE* outStream;
 		std::string sections;
 		int minLevel;
+		bool flush;
 	};
 	typedef std::map<std::string, LogFileDetails> logFiles_t;
 
@@ -105,17 +110,15 @@ namespace {
 		return (!log_file_getLogFiles().empty());
 	}
 
-	void log_file_writeToFile(FILE* outStream, const char* record) {
+	void log_file_writeToFile(FILE* outStream, const char* record, bool flush) {
 
 		char framePrefix[128] = {'\0'};
 		log_framePrefixer_createPrefix(framePrefix, sizeof(framePrefix));
 
 		FPRINTF(outStream, "%s%s\n", framePrefix, record);
 
-		// We never flush, but only close the stream before process exit.
-		// This decision was made in two engine dev meetings, the last one was
-		// at 26. September 2011.
-		//fflush(outStream);
+		if (flush)
+			fflush(outStream);
 	}
 
 	/**
@@ -130,7 +133,7 @@ namespace {
 			if (lfi->second.IsLogging(section, level)
 					&& (lfi->second.GetOutStream() != NULL))
 			{
-				log_file_writeToFile(lfi->second.GetOutStream(), record);
+				log_file_writeToFile(lfi->second.GetOutStream(), record, lfi->second.IsFlush());
 			}
 		}
 	}
@@ -182,7 +185,7 @@ namespace {
 extern "C" {
 #endif
 
-void log_file_addLogFile(const char* filePath, const char* sections, int minLevel) {
+void log_file_addLogFile(const char* filePath, const char* sections, int minLevel, bool flush) {
 
 	assert(filePath != NULL);
 
@@ -209,7 +212,7 @@ void log_file_addLogFile(const char* filePath, const char* sections, int minLeve
 	setvbuf(tmpStream, NULL, _IOFBF, (BUFSIZ < 8192) ? BUFSIZ : 8192); // limit buffer to 8kB
 
 	const std::string sectionsStr = (sections == NULL) ? "" : sections;
-	logFiles[filePathStr] = LogFileDetails(tmpStream, sectionsStr, minLevel);
+	logFiles[filePathStr] = LogFileDetails(tmpStream, sectionsStr, minLevel, flush);
 }
 
 void log_file_removeLogFile(const char* filePath) {

rts/System/Log/FileSink.h

@@ -26,10 +26,11 @@ extern "C" {
  * @param filePath the path to the log file
  * @param sections A list of comma separated sections to log to the file or
  *   NULL to log everything. To include the default section, you have to include
+ * @param flush instantly flush the logfile after data was written, will cause a slowdown
  *   ",,".
  */
 void log_file_addLogFile(const char* filePath, const char* sections = NULL,
-		int minLevel = LOG_LEVEL_ALL);
+		int minLevel = LOG_LEVEL_ALL, bool flush = false);
 
 void log_file_removeLogFile(const char* filePath);
 

rts/System/LogOutput.cpp

@@ -34,9 +34,12 @@
 /******************************************************************************/
 /******************************************************************************/
 
-CONFIG(std::string, RotateLogFiles).defaultValue("auto");
-CONFIG(std::string, LogSections).defaultValue("");
-CONFIG(std::string, LogSubsystems).defaultValue(""); // XXX deprecated on 22. August 2011, before the 0.83 release
+CONFIG(std::string, RotateLogFiles).defaultValue("auto")
+		.description("rotate logfiles, valid values are \"always\" (default in debug builds) and \"never\" (default in release builds).");
+CONFIG(std::string, LogSections).defaultValue("")
+		.description("Comma seperated list of enabled logsections, see infolog.txt / console output for possible values");
+CONFIG(bool, LogFlush).defaultValue(false)
+		.description("Instantly write to the logfile, use only for debugging as it will cause a slowdown");
 
 /******************************************************************************/
 /******************************************************************************/
@@ -158,7 +161,8 @@ void CLogOutput::Initialize()
 	/*filelog = new std::ofstream(filePath.c_str());
 	if (filelog->bad())
 		SafeDelete(filelog);*/
-	log_file_addLogFile(filePath.c_str());
+	const bool flush = configHandler->GetBool("LogFlush");
+	log_file_addLogFile(filePath.c_str(), NULL, LOG_LEVEL_ALL, flush);
 
 	initialized = true;
 	InitializeSections();
@@ -214,20 +218,14 @@ void CLogOutput::InitializeSections()
 	enabledSections += "Sound,";
 	#endif
 	enabledSections += StringToLower(configHandler->GetString("LogSections")) + ",";
-	enabledSections += StringToLower(configHandler->GetString("LogSubsystems")) + ","; // XXX deprecated on 22. August 2011, before the 0.83 release
 #endif
 
 	const char* const envSec = getenv("SPRING_LOG_SECTIONS");
-	const char* const envSubsys = getenv("SPRING_LOG_SUBSYSTEMS"); // XXX deprecated on 22. August 2011, before the 0.83 release
 	std::string env;
 	if (envSec != NULL) {
 		env += ",";
 		env += envSec;
 	}
-	if (envSubsys != NULL) {
-		env += ",";
-		env += envSubsys;
-	}
 
 	if (!env.empty()) {
 		// this allows to disable all sections from the env var