github.com/timstclair/heapster@v0.20.0-alpha1/Godeps/_workspace/src/k8s.io/kubernetes/pkg/util/line_delimiter.go (about)

     1  /*
     2  Copyright 2015 The Kubernetes Authors All rights reserved.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8      http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package util
    18  
    19  import (
    20  	"bytes"
    21  	"io"
    22  	"strings"
    23  )
    24  
    25  // A Line Delimiter is a filter that will
    26  type LineDelimiter struct {
    27  	output    io.Writer
    28  	delimiter []byte
    29  	buf       bytes.Buffer
    30  }
    31  
    32  // NewLineDelimiter allocates a new io.Writer that will split input on lines
    33  // and bracket each line with the delimiter string.  This can be useful in
    34  // output tests where it is difficult to see and test trailing whitespace.
    35  func NewLineDelimiter(output io.Writer, delimiter string) *LineDelimiter {
    36  	return &LineDelimiter{output: output, delimiter: []byte(delimiter)}
    37  }
    38  
    39  // Write writes buf to the LineDelimiter ld. The only errors returned are ones
    40  // encountered while writing to the underlying output stream.
    41  func (ld *LineDelimiter) Write(buf []byte) (n int, err error) {
    42  	return ld.buf.Write(buf)
    43  }
    44  
    45  // Flush all lines up until now.  This will assume insert a linebreak at the current point of the stream.
    46  func (ld *LineDelimiter) Flush() (err error) {
    47  	lines := strings.Split(ld.buf.String(), "\n")
    48  	for _, line := range lines {
    49  		if _, err = ld.output.Write(ld.delimiter); err != nil {
    50  			return
    51  		}
    52  		if _, err = ld.output.Write([]byte(line)); err != nil {
    53  			return
    54  		}
    55  		if _, err = ld.output.Write(ld.delimiter); err != nil {
    56  			return
    57  		}
    58  		if _, err = ld.output.Write([]byte("\n")); err != nil {
    59  			return
    60  		}
    61  	}
    62  	return
    63  }