mylog.go

// Copyright (c) 2022 hxx258456
// github.com/hxx258456/mylog is licensed under Mulan PSL v2.

package mylog

import (
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"strconv"
)

// 日志级别
type Level int8

const (
	// 调试
	DebugLevel Level = iota
	// 信息
	InfoLevel
	// 警告
	WarnLevel
	// 错误
	ErrorLevel
	// 致命错误
	FatalLevel
	// 异常
	PanicLevel
	// defines an absent log level.
	NoLevel
	// 禁用
	Disabled

	// 堆栈跟踪
	TraceLevel Level = -1
	// Values less than TraceLevel are handled as numbers.
)

func (l Level) String() string {
	switch l {
	case TraceLevel:
		return LevelTraceValue
	case DebugLevel:
		return LevelDebugValue
	case InfoLevel:
		return LevelInfoValue
	case WarnLevel:
		return LevelWarnValue
	case ErrorLevel:
		return LevelErrorValue
	case FatalLevel:
		return LevelFatalValue
	case PanicLevel:
		return LevelPanicValue
	case Disabled:
		return "disabled"
	case NoLevel:
		return ""
	}
	return strconv.Itoa(int(l))
}

// level检查
func ParseLevel(levelStr string) (Level, error) {
	switch levelStr {
	case LevelFieldMarshalFunc(TraceLevel):
		return TraceLevel, nil
	case LevelFieldMarshalFunc(DebugLevel):
		return DebugLevel, nil
	case LevelFieldMarshalFunc(InfoLevel):
		return InfoLevel, nil
	case LevelFieldMarshalFunc(WarnLevel):
		return WarnLevel, nil
	case LevelFieldMarshalFunc(ErrorLevel):
		return ErrorLevel, nil
	case LevelFieldMarshalFunc(FatalLevel):
		return FatalLevel, nil
	case LevelFieldMarshalFunc(PanicLevel):
		return PanicLevel, nil
	case LevelFieldMarshalFunc(Disabled):
		return Disabled, nil
	case LevelFieldMarshalFunc(NoLevel):
		return NoLevel, nil
	}
	i, err := strconv.Atoi(levelStr)
	if err != nil {
		return NoLevel, errors.New("Unknown Level String: '" + levelStr + "', defaulting to NoLevel")
	}
	if i > 127 || i < -128 {
		return NoLevel, errors.New("Out-Of-Bounds Level: '" + strconv.Itoa(i) + "', defaulting to NoLevel")
	}
	return Level(i), nil
}

type Logger struct {
	w       LevelWriter
	level   Level
	sampler Sampler
	context []byte
	hooks   []Hook
	stack   bool
}

// 日志写入器,分辨同步还是异步
func New(w io.Writer) Logger {
	if w == nil {
		w = ioutil.Discard
	}
	lw, ok := w.(LevelWriter)
	if !ok {
		lw = levelWriterAdapter{w}
	}
	return Logger{w: lw, level: TraceLevel}
}

// Nop returns a disabled logger for which all operation are no-op.
func Nop() Logger {
	return New(nil).Level(Disabled)
}

// Output duplicates the current logger and sets w as its output.
func (l Logger) Output(w io.Writer) Logger {
	l2 := New(w)
	l2.level = l.level
	l2.sampler = l.sampler
	l2.stack = l.stack
	if len(l.hooks) > 0 {
		l2.hooks = append(l2.hooks, l.hooks...)
	}
	if l.context != nil {
		l2.context = make([]byte, len(l.context), cap(l.context))
		copy(l2.context, l.context)
	}
	return l2
}

// With creates a child logger with the field added to its context.
func (l Logger) With() Context {
	context := l.context
	l.context = make([]byte, 0, 500)
	if context != nil {
		l.context = append(l.context, context...)
	} else {
		// This is needed for AppendKey to not check len of input
		// thus making it inlinable
		l.context = enc.AppendBeginMarker(l.context)
	}
	return Context{l}
}

// UpdateContext updates the internal logger's context.
//
// Use this method with caution. If unsure, prefer the With method.
func (l *Logger) UpdateContext(update func(c Context) Context) {
	if l == disabledLogger {
		return
	}
	if cap(l.context) == 0 {
		l.context = make([]byte, 0, 500)
	}
	if len(l.context) == 0 {
		l.context = enc.AppendBeginMarker(l.context)
	}
	c := update(Context{*l})
	l.context = c.l.context
}

// Level creates a child logger with the minimum accepted level set to level.
func (l Logger) Level(lvl Level) Logger {
	l.level = lvl
	return l
}

// GetLevel returns the current Level of l.
func (l Logger) GetLevel() Level {
	return l.level
}

// Sample returns a logger with the s sampler.
func (l Logger) Sample(s Sampler) Logger {
	l.sampler = s
	return l
}

// Hook returns a logger with the h Hook.
func (l Logger) Hook(h Hook) Logger {
	l.hooks = append(l.hooks, h)
	return l
}

// Trace starts a new message with trace level.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Trace() *Event {
	return l.newEvent(TraceLevel, nil)
}

// Debug starts a new message with debug level.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Debug() *Event {
	return l.newEvent(DebugLevel, nil)
}

// Info starts a new message with info level.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Info() *Event {
	return l.newEvent(InfoLevel, nil)
}

// Warn starts a new message with warn level.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Warn() *Event {
	return l.newEvent(WarnLevel, nil)
}

// Error starts a new message with error level.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Error() *Event {
	return l.newEvent(ErrorLevel, nil)
}

// Err starts a new message with error level with err as a field if not nil or
// with info level if err is nil.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Err(err error) *Event {
	if err != nil {
		return l.Error().Err(err)
	}

	return l.Info()
}

// Fatal starts a new message with fatal level. The os.Exit(1) function
// is called by the Msg method, which terminates the program immediately.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Fatal() *Event {
	return l.newEvent(FatalLevel, func(msg string) { os.Exit(1) })
}

// Panic starts a new message with panic level. The panic() function
// is called by the Msg method, which stops the ordinary flow of a goroutine.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Panic() *Event {
	return l.newEvent(PanicLevel, func(msg string) { panic(msg) })
}

// WithLevel starts a new message with level. Unlike Fatal and Panic
// methods, WithLevel does not terminate the program or stop the ordinary
// flow of a goroutine when used with their respective levels.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) WithLevel(level Level) *Event {
	switch level {
	case TraceLevel:
		return l.Trace()
	case DebugLevel:
		return l.Debug()
	case InfoLevel:
		return l.Info()
	case WarnLevel:
		return l.Warn()
	case ErrorLevel:
		return l.Error()
	case FatalLevel:
		return l.newEvent(FatalLevel, nil)
	case PanicLevel:
		return l.newEvent(PanicLevel, nil)
	case NoLevel:
		return l.Log()
	case Disabled:
		return nil
	default:
		return l.newEvent(level, nil)
	}
}

// Log starts a new message with no level. Setting GlobalLevel to Disabled
// will still disable events produced by this method.
//
// You must call Msg on the returned event in order to send the event.
func (l *Logger) Log() *Event {
	return l.newEvent(NoLevel, nil)
}

// Print sends a log event using debug level and no extra field.
// Arguments are handled in the manner of fmt.Print.
func (l *Logger) Print(v ...interface{}) {
	if e := l.Debug(); e.Enabled() {
		e.CallerSkipFrame(1).Msg(fmt.Sprint(v...))
	}
}

// Printf sends a log event using debug level and no extra field.
// Arguments are handled in the manner of fmt.Printf.
func (l *Logger) Printf(format string, v ...interface{}) {
	if e := l.Debug(); e.Enabled() {
		e.CallerSkipFrame(1).Msg(fmt.Sprintf(format, v...))
	}
}

// Write implements the io.Writer interface. This is useful to set as a writer
// for the standard library log.
func (l Logger) Write(p []byte) (n int, err error) {
	n = len(p)
	if n > 0 && p[n-1] == '\n' {
		// Trim CR added by stdlog.
		p = p[0 : n-1]
	}
	l.Log().CallerSkipFrame(1).Msg(B2s(p))
	return
}

func (l *Logger) newEvent(level Level, done func(string)) *Event {
	enabled := l.should(level)
	if !enabled {
		if done != nil {
			done("")
		}
		return nil
	}
	e := newEvent(l.w, level)
	e.done = done
	e.ch = l.hooks
	if level != NoLevel && LevelFieldName != "" {
		e.Str(LevelFieldName, LevelFieldMarshalFunc(level))
	}
	if l.context != nil && len(l.context) > 1 {
		e.buf = enc.AppendObjectData(e.buf, l.context)
	}
	if l.stack {
		e.Stack()
	}
	return e
}

// should returns true if the log event should be logged.
func (l *Logger) should(lvl Level) bool {
	if lvl < l.level || lvl < GlobalLevel() {
		return false
	}
	if l.sampler != nil && !samplingDisabled() {
		return l.sampler.Sample(lvl)
	}
	return true
}