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backends/log/log.h

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef BACKENDS_LOG_LOG_H
+#define BACKENDS_LOG_LOG_H
+
+#include "common/scummsys.h"
+
+class OSystem;
+
+namespace Common {
+class WriteStream;
+} // End of namespace Common
+
+namespace Backends {
+namespace Log {
+
+/**
+ * Log file writer.
+ *
+ * This can be used by the backends to implement file logging functionality.
+ */
+class Log {
+public:
+	/**
+	 * Constructor for the logger object.
+	 *
+	 * @param system The OSystem instance to use. Must be non-null.
+	 */
+	Log(OSystem *system);
+	~Log() { close(); }
+
+	/**
+	 * Opens a new log file.
+	 *
+	 * The previous log, which was handled by this logger, will be closed
+	 * before the new stream is associated.
+	 *
+	 * The current implemention will always call flush after data is written
+	 * to the log file. It might thus be wise to pass an unbuffered write
+	 * stream here to avoid unnecessary overhead.
+	 * @see Common::WriteStream::flush
+	 *
+	 * Calling open with stream being 0 is valid and will result in the same
+	 * behavior as calling close, but it may have additional overhead.
+	 * @see close
+	 *
+	 * This function will output information about the ScummVM version and
+	 * the features built into ScummVM automatically. It will also add a short
+	 * notice to indicate that the log was opened successfully.
+	 *
+	 * @param stream Stream where to output the log contents.
+	 *               Note that the stream will be deleted by the logger.
+	 */
+	void open(Common::WriteStream *stream);
+
+	/**
+	 * Closes the current log file.
+	 *
+	 * This function will output a line saying that the log was closed
+	 * successfully. This can be used to check whether a log is incomplete
+	 * because of whatever reasons.
+	 */
+	void close();
+
+	/**
+	 * Prints a message to the log stream.
+	 *
+	 * This has optional support to output a timestamp on every new line.
+	 * The timestamp will look like: "[YYYY-MM-DD HH:MM:SS] ".
+	 * Printing of a timestamp is done by default.
+	 *
+	 * It might be noteworthy that this function does not append a new line
+	 * to the given message.
+	 *
+	 * In case no stream is associated with this logger, this function will
+	 * quit immediately.
+	 *
+	 * @param message            The message to write.
+	 * @param printTimeOnNewline Whether to print a timestamp on the start of
+	 *                           a new line.
+	 */
+	void print(const char *message, const bool printTimeOnNewline = true);
+private:
+	/**
+	 * Prints a time stamp in the form: "[YYYY-MM-DD HH:MM:SS] ".
+	 */
+	void printTimeStamp();
+
+	/**
+	 * The OSystem instance used to query data like the time.
+	 */
+	OSystem *_system;
+
+	/**
+	 * Where to write the output too.
+	 */
+	Common::WriteStream *_stream;
+
+	/**
+	 * Whether we are at the start of a line.
+	 */
+	bool _startOfLine;
+};
+
+} // End of namespace Log
+} // End of namespace Backends
+
+#endif