OnlineLibrary

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package log
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import (
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	"fmt"
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	"io"
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	"path/filepath"
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	"runtime"
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	"strings"
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	"sync"
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	"time"
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)
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type Level int
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const (
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	Error Level = iota
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	Info
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	Warning
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	Debug
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)
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func (l Level) String() string {
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	switch l {
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	case Error:
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		return "ERROR"
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	case Info:
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		return "INFO"
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	case Warning:
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		return "WARNING"
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	case Debug:
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		return "DEBUG"
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	default:
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		return "UNKNOWN"
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	}
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}
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func StringToLevel(str string) (Level, error) {
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	switch str {
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	case Error.String():
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		return Error, nil
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	case Info.String():
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		return Info, nil
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	case Warning.String():
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		return Warning, nil
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	case Debug.String():
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		return Debug, nil
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	default:
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		return 0, fmt.Errorf("%v is not a supported log level", str)
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	}
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}
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type Logger struct {
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	mu     sync.Mutex
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	level  Level
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	indent string
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	out    io.Writer
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}
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func New(out io.Writer, level Level, indent string) *Logger {
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	return &Logger{out: out, level: level, indent: indent}
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}
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func (l *Logger) log(calldepth int, level Level, format string, args ...any) {
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	l.mu.Lock()
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	defer l.mu.Unlock()
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	if l.level < level || l.out == nil {
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		return
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	}
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	hour, min, sec := time.Now().Clock()
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	clock := fmt.Sprintf("%02d:%02d:%02d", hour, min, sec)
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	_, file, line, ok := runtime.Caller(calldepth)
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	if !ok {
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		file = "???"
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		line = 0
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	}
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	msg := fmt.Sprintf(strings.ReplaceAll(format, "\n", "\n"+l.indent), args...)
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	fmt.Fprintf(l.out, "%v - %v:%v (%v):\r\n%v%v\r\n", level, filepath.Base(file), line, clock, l.indent, msg)
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}
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func (l *Logger) Error(format string, args ...any) {
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	l.log(2, Error, format, args...)
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}
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func (l *Logger) Info(format string, args ...any) {
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	l.log(2, Info, format, args...)
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}
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func (l *Logger) Warning(format string, args ...any) {
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	l.log(2, Warning, format, args...)
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}
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func (l *Logger) Debug(format string, args ...any) {
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	l.log(2, Debug, format, args...)
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}
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func (l *Logger) SetOutput(out io.Writer) {
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	l.mu.Lock()
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	defer l.mu.Unlock()
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	l.out = out
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}
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func (l *Logger) SetLevel(level Level) error {
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	l.mu.Lock()
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	defer l.mu.Unlock()
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	if level < Error || level > Debug {
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		return fmt.Errorf("unsupported log level: %v", level)
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	}
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	l.level = level
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	return nil
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}
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func (l *Logger) Level() Level {
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	l.mu.Lock()
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	defer l.mu.Unlock()
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	return l.level
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}
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func (l *Logger) SupportedLevels() []Level {
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	return []Level{Error, Info, Warning, Debug}
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}
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