added simple, fast, and efficient logging

src/lib/utils/log.cpp

@@ -0,0 +1,140 @@
+/*
+ * 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/.
+ */
+
+#include "log.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <time.h>
+#include <sys/time.h>
+#include <stdarg.h>
+
+using namespace std;
+
+/** the name of each @a LogFacility. */
+static const char *facilityNames[] = {
+	"main",
+	"network",
+	"bus",
+	"update",
+	"all",
+	NULL
+};
+
+/** the name of each @a LogLevel. */
+static const char* levelNames[] = {
+	"none",
+	"error",
+	"notice",
+	"info",
+	"debug",
+	NULL
+};
+
+/** the bit combination of currently active log facilities (1 << @a LogFacility). */
+static int logFacilites = LF_ALL;
+
+/** the current log level. */
+static LogLevel logLevel = ll_notice;
+
+/** the current log FILE. */
+static FILE* logFile = stdout;
+
+bool setLogFacilities(const char* facilities)
+{
+	char *opt = (char*)facilities, *value = NULL;
+	int newFacilites = 0;
+	while (*opt) {
+		int val = getsubopt(&opt, (char *const *)facilityNames, &value);
+		if (val < 0 || val > lf_COUNT || value)
+			return false;
+		if (val == lf_COUNT) {
+			newFacilites = LF_ALL;
+			break;
+		}
+		newFacilites |= 1<<val;
+	}
+
+	logFacilites = newFacilites;
+	return true;
+}
+
+bool setLogLevel(const char* level)
+{
+	char *opt = (char*)level, *value = NULL;
+	int newLevel = 0;
+	if (*opt) {
+		int val = getsubopt(&opt, (char *const *)levelNames, &value);
+		if (val < 0 || val >= ll_COUNT || value || *opt)
+			return false;
+		newLevel = val;
+	}
+
+	logLevel = (LogLevel)newLevel;
+	return true;
+}
+
+bool setLogFile(const char* filename)
+{
+	FILE* newFile = fopen(filename, "w");
+	if (newFile == NULL)
+		return false;
+
+	closeLogFile();
+	logFile = newFile;
+	return true;
+}
+
+void closeLogFile()
+{
+	if (logFile != NULL) {
+		fclose(logFile);
+		logFile = NULL;
+	}
+}
+
+bool needsLog(const LogFacility facility, const LogLevel level)
+{
+	return ((logFacilites & (1<<facility)) != 0)
+		&& (logLevel >= level);
+}
+
+void logWrite(const LogFacility facility, const LogLevel level, const char* message, ...)
+{
+	struct timespec ts;
+	struct tm* tm;
+
+	clock_gettime(CLOCK_REALTIME, &ts);
+	tm = localtime(&ts.tv_sec);
+
+	char* buf;
+	va_list ap;
+	va_start(ap, message);
+
+	if (vasprintf(&buf, message, ap) >= 0 && buf) {
+		fprintf(logFile, "%04d-%02d-%02d %02d:%02d:%02d.%03ld [%s %s] %s\n",
+			tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
+			tm->tm_hour, tm->tm_min, tm->tm_sec, ts.tv_nsec/1000000,
+			facilityNames[facility], levelNames[level], buf);
+		fflush(logFile);
+	}
+
+	va_end(ap);
+	if (buf)
+		free(buf);
+}