Adding upstream version 2.52.6.

Signed-off-by: Daniel Baumann <daniel@debian.org>

log/log.go

@@ -0,0 +1,100 @@
+package log
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"os"
+)
+
+var logger AllLogger = &defaultLogger{
+	stdlog: log.New(os.Stderr, "", log.LstdFlags|log.Lshortfile|log.Lmicroseconds),
+	depth:  4,
+}
+
+// Logger is a logger interface that provides logging function with levels.
+type Logger interface {
+	Trace(v ...interface{})
+	Debug(v ...interface{})
+	Info(v ...interface{})
+	Warn(v ...interface{})
+	Error(v ...interface{})
+	Fatal(v ...interface{})
+	Panic(v ...interface{})
+}
+
+// FormatLogger is a logger interface that output logs with a format.
+type FormatLogger interface {
+	Tracef(format string, v ...interface{})
+	Debugf(format string, v ...interface{})
+	Infof(format string, v ...interface{})
+	Warnf(format string, v ...interface{})
+	Errorf(format string, v ...interface{})
+	Fatalf(format string, v ...interface{})
+	Panicf(format string, v ...interface{})
+}
+
+// WithLogger is a logger interface that output logs with a message and key-value pairs.
+type WithLogger interface {
+	Tracew(msg string, keysAndValues ...interface{})
+	Debugw(msg string, keysAndValues ...interface{})
+	Infow(msg string, keysAndValues ...interface{})
+	Warnw(msg string, keysAndValues ...interface{})
+	Errorw(msg string, keysAndValues ...interface{})
+	Fatalw(msg string, keysAndValues ...interface{})
+	Panicw(msg string, keysAndValues ...interface{})
+}
+
+type CommonLogger interface {
+	Logger
+	FormatLogger
+	WithLogger
+}
+
+// ControlLogger provides methods to config a logger.
+type ControlLogger interface {
+	SetLevel(Level)
+	SetOutput(io.Writer)
+}
+
+// AllLogger is the combination of Logger, FormatLogger, CtxLogger and ControlLogger.
+// Custom extensions can be made through AllLogger
+type AllLogger interface {
+	CommonLogger
+	ControlLogger
+	WithContext(ctx context.Context) CommonLogger
+}
+
+// Level defines the priority of a log message.
+// When a logger is configured with a level, any log message with a lower
+// log level (smaller by integer comparison) will not be output.
+type Level int
+
+// The levels of logs.
+const (
+	LevelTrace Level = iota
+	LevelDebug
+	LevelInfo
+	LevelWarn
+	LevelError
+	LevelFatal
+	LevelPanic
+)
+
+var strs = []string{
+	"[Trace] ",
+	"[Debug] ",
+	"[Info] ",
+	"[Warn] ",
+	"[Error] ",
+	"[Fatal] ",
+	"[Panic] ",
+}
+
+func (lv Level) toString() string {
+	if lv >= LevelTrace && lv <= LevelPanic {
+		return strs[lv]
+	}
+	return fmt.Sprintf("[?%d] ", lv)
+}