BACKENDS: Add a basic logger implementation.

This is the logger I posted at our patch tracker. Item #3115757
"OSYSTEM: Basic logger". It includes the changes proposed by Max.

It is currently not hooked into any backend, since we still need to decide
where to log files, whether to have multiple log files etc.

svn-id: r54451

1 files changed, 107 insertions, 0 deletions

diff --git a/backends/log/log.cpp b/backends/log/log.cpp
new file mode 100644
index 0000000000..e7fb924189
--- /dev/null
+++ b/backends/log/log.cpp
@@ -0,0 +1,107 @@
+/* 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 2
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "backends/log/log.h"
+
+#include "common/stream.h"
+#include "common/str.h"
+#include "common/system.h"
+
+#include "base/version.h"
+
+namespace Backends {
+namespace Log {
+
+Log::Log(OSystem *system)
+    : _system(system), _stream(0), _startOfLine(true) {
+	assert(system);
+}
+
+void Log::open(Common::WriteStream *stream) {
+	// Close the previous log
+	close();
+
+	_stream = stream;
+
+	// Output information about the ScummVM version at the start of the log
+	// file
+	print(gScummVMFullVersion);
+	print("\n");
+	print(gScummVMFeatures);
+	print("\n");
+	print("--- Log opened.\n");
+}
+
+void Log::close() {
+	if (_stream) {
+		// Output a message to indicate that the log was closed successfully
+		print("--- Log closed successfully.\n");
+
+		delete _stream;
+		_stream = 0;
+	}
+}
+
+void Log::print(const char *message, const bool printTime) {
+	if (!_stream)
+		return;
+
+	while (*message) {
+		if (_startOfLine) {
+			_startOfLine = false;
+			if (printTime)
+				printTimeStamp();
+		}
+
+		const char *msgStart = message;
+		// scan for end of line/string
+		while (*message && *message != '\n')
+			++message;
+
+		if (*message == '\n') {
+			++message;
+			_startOfLine = true;
+		}
+
+		// TODO: It might be wise to check for write errors and/or incomplete
+		// writes here, since losing certain bits of the log is not nice.
+		_stream->write(msgStart, message - msgStart);
+	}
+
+	_stream->flush();
+}
+
+void Log::printTimeStamp() {
+	TimeDate date;
+	_system->getTimeAndDate(date);
+
+	_stream->writeString(Common::String::format("[%d-%02d-%02d %02d:%02d:%02d] ",
+	                     date.tm_year + 1900, date.tm_mon, date.tm_mday,
+	                     date.tm_hour, date.tm_min, date.tm_sec));
+}
+
+} // End of namespace Log
+} // End of namespace Backends
+