added simple, fast, and efficient logging

src/lib/utils/log.h

@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) John Baier 2014-2015 <ebusd@johnm.de>
+ *
+ * This file is part of ebusd.
+ *
+ * ebusd is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ebusd is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with ebusd. If not, see http://www.gnu.org/licenses/.
+ */
+
+#ifndef LIBUTILS_LOG_H_
+#define LIBUTILS_LOG_H_
+
+/** \file log.h */
+
+/** the available log facilities. */
+enum LogFacility {
+	lf_main=0,  //!< main loop
+	lf_network, //!< network related
+	lf_bus,     //!< eBUS related
+	lf_update,  //!< updates found while listening to the bus
+	lf_COUNT=4  //!< number of available log facilities
+};
+
+/** macro for enabling all log facilities. */
+#define LF_ALL ((1<<lf_main) | (1<<lf_network) | (1<<lf_bus) | (1<<lf_update))
+
+/** the available log levels. */
+enum LogLevel {
+	ll_none=0, //!< no level at all
+	ll_error,  //!< error message
+	ll_notice, //!< important message
+	ll_info,   //!< informational message
+	ll_debug,  //!< debugging message (normally suppressed)
+	ll_COUNT=5 //!< number of available log levels
+};
+
+/**
+ * Set the log facilities from the string.
+ * @param facilities the string to parse the facilities from (separated by comma).
+ * @return true on success, false on error.
+ */
+bool setLogFacilities(const char* facilities);
+
+/**
+ * Parse the log level from the string.
+ * @param level the level as string.
+ * @return true on success, false on error.
+ */
+bool setLogLevel(const char* level);
+
+/**
+ * Set the log file to use.
+ * @param filename the name of the log file to use.
+ * @return true on success, false on error.
+ */
+bool setLogFile(const char* filename);
+
+/**
+ * Close the log file if necessary.
+ */
+void closeLogFile();
+
+/**
+ * Return whether logging is needed for the specified facility and level.
+ * @param facility the @a LogFacility of the message to check.
+ * @param level the @a LogLevel of the message to check.
+ * @return true when logging is needed for the specified facility and level.
+ */
+bool needsLog(const LogFacility facility, const LogLevel level);
+
+/**
+ * Log the message for the specified @a LogFacility and @a LogLevel (even if logging is not needed for the facility/level).
+ * @param facility the @a LogFacility of the message to log.
+ * @param level the @a LogLevel of the message to log.
+ * @param message the message to log.
+ * @param ... variable arguments depending on the @a message.
+ */
+void logWrite(const LogFacility facility, const LogLevel level, const char* message, ...);
+
+/** A macro that calls the logging function only if needed. */
+#define LOG(facility, level, ...) (needsLog(facility, level) ? logWrite(facility, level, __VA_ARGS__) : void(0))
+
+/** A macro for an error message that calls the logging function only if needed. */
+#define logError(facility, ...) (needsLog(facility, ll_error) ? logWrite(facility, ll_error, __VA_ARGS__) : void(0))
+
+/** A macro for a notice message that calls the logging function only if needed. */
+#define logNotice(facility, ...) (needsLog(facility, ll_notice) ? logWrite(facility, ll_notice, __VA_ARGS__) : void(0))
+
+/** A macro for an info message that calls the logging function only if needed. */
+#define logInfo(facility, ...) (needsLog(facility, ll_info) ? logWrite(facility, ll_info, __VA_ARGS__) : void(0))
+
+/** A macro for a debug message that calls the logging function only if needed. */
+#define logDebug(facility, ...) (needsLog(facility, ll_debug) ? logWrite(facility, ll_debug, __VA_ARGS__) : void(0))
+
+
+#endif // LIBUTILS_LOG_H_