go-hep.org/x/hep@v0.38.1/fwk/msgstream.go (about)

     1  // Copyright ©2017 The go-hep Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package fwk
     6  
     7  import (
     8  	"fmt"
     9  	"io"
    10  	"os"
    11  )
    12  
    13  // WriteSyncer is an io.Writer which can be sync'ed/flushed.
    14  type WriteSyncer interface {
    15  	io.Writer
    16  	Sync() error
    17  }
    18  
    19  type msgstream struct {
    20  	lvl Level
    21  	w   WriteSyncer
    22  	n   string
    23  }
    24  
    25  // NewMsgStream creates a new MsgStream value with name name and minimum
    26  // verbosity level lvl.
    27  // This MsgStream will print messages into w.
    28  func NewMsgStream(name string, lvl Level, w WriteSyncer) MsgStream {
    29  	return newMsgStream(name, lvl, w)
    30  }
    31  
    32  func newMsgStream(name string, lvl Level, w WriteSyncer) msgstream {
    33  	if w == nil {
    34  		w = os.Stdout
    35  	}
    36  
    37  	return msgstream{
    38  		lvl: lvl,
    39  		w:   w,
    40  		n:   fmt.Sprintf("%-20s ", name),
    41  	}
    42  }
    43  
    44  // Debugf displays a (formated) DBG message
    45  func (msg msgstream) Debugf(format string, a ...any) {
    46  	msg.Msg(LvlDebug, format, a...)
    47  }
    48  
    49  // Infof displays a (formated) INFO message
    50  func (msg msgstream) Infof(format string, a ...any) {
    51  	msg.Msg(LvlInfo, format, a...)
    52  }
    53  
    54  // Warnf displays a (formated) WARN message
    55  func (msg msgstream) Warnf(format string, a ...any) {
    56  	defer msg.flush()
    57  	msg.Msg(LvlWarning, format, a...)
    58  }
    59  
    60  // Errorf displays a (formated) ERR message
    61  func (msg msgstream) Errorf(format string, a ...any) {
    62  	defer msg.flush()
    63  	msg.Msg(LvlError, format, a...)
    64  }
    65  
    66  // Msg displays a (formated) message with level lvl.
    67  func (msg msgstream) Msg(lvl Level, format string, a ...any) {
    68  	if lvl < msg.lvl {
    69  		return
    70  	}
    71  	format = msg.n + msg.lvl.msgstring() + " " + format
    72  	fmt.Fprintf(msg.w, format, a...)
    73  }
    74  
    75  func (msg msgstream) flush() error {
    76  	return msg.w.Sync()
    77  }