1 files changed, 63 insertions, 0 deletions
diff --git a/logger/logsystem.go b/logger/logsystem.go
new file mode 100644
index 000000000..8458b938f
--- /dev/null
+++ b/logger/logsystem.go
@@ -0,0 +1,63 @@
+package logger
+
+import (
+	"io"
+	"log"
+	"sync/atomic"
+)
+
+// LogSystem is implemented by log output devices.
+// All methods can be called concurrently from multiple goroutines.
+type LogSystem interface {
+	GetLogLevel() LogLevel
+	SetLogLevel(i LogLevel)
+	LogPrint(LogLevel, string)
+}
+
+// NewStdLogSystem creates a LogSystem that prints to the given writer.
+// The flag values are defined package log.
+func NewStdLogSystem(writer io.Writer, flags int, level LogLevel) LogSystem {
+	logger := log.New(writer, "", flags)
+	return &stdLogSystem{logger, uint32(level)}
+}
+
+type stdLogSystem struct {
+	logger *log.Logger
+	level  uint32
+}
+
+func (t *stdLogSystem) LogPrint(level LogLevel, msg string) {
+	t.logger.Print(msg)
+}
+
+func (t *stdLogSystem) SetLogLevel(i LogLevel) {
+	atomic.StoreUint32(&t.level, uint32(i))
+}
+
+func (t *stdLogSystem) GetLogLevel() LogLevel {
+	return LogLevel(atomic.LoadUint32(&t.level))
+}
+
+// NewRawLogSystem creates a LogSystem that prints to the given writer without
+// adding extra information. Suitable for preformatted output
+func NewRawLogSystem(writer io.Writer, flags int, level LogLevel) LogSystem {
+	logger := log.New(writer, "", 0)
+	return &rawLogSystem{logger, uint32(level)}
+}
+
+type rawLogSystem struct {
+	logger *log.Logger
+	level  uint32
+}
+
+func (t *rawLogSystem) LogPrint(level LogLevel, msg string) {
+	t.logger.Print(msg)
+}
+
+func (t *rawLogSystem) SetLogLevel(i LogLevel) {
+	atomic.StoreUint32(&t.level, uint32(i))
+}
+
+func (t *rawLogSystem) GetLogLevel() LogLevel {
+	return LogLevel(atomic.LoadUint32(&t.level))
+}