go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/data/text/color/strip.go (about)

     1  // Copyright 2019 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package color
    16  
    17  import (
    18  	"bytes"
    19  	"io"
    20  )
    21  
    22  // StripWriter strips all color codes.
    23  type StripWriter struct {
    24  	io.Writer
    25  }
    26  
    27  var colorStart = []byte("\033[")
    28  
    29  func (w *StripWriter) Write(p []byte) (n int, err error) {
    30  	for len(p) > 0 {
    31  		var toWrite []byte
    32  		start := bytes.Index(p, colorStart)
    33  		if start != -1 {
    34  			relEnd := bytes.IndexRune(p[start:], 'm')
    35  			if relEnd != -1 {
    36  				toWrite = p[:start]
    37  				p = p[start+relEnd+1:]
    38  			}
    39  		}
    40  		if toWrite == nil {
    41  			toWrite = p
    42  			p = nil
    43  		}
    44  
    45  		var wrote int
    46  		wrote, err = w.Writer.Write(toWrite)
    47  		n += wrote
    48  		if err != nil {
    49  			break
    50  		}
    51  	}
    52  	return
    53  }