1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
|
// Copyright 2018 Google Inc. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package terminal provides a set of interfaces that can be used to interact
// with the terminal (including falling back when the terminal is detected to
// be a redirect or other dumb terminal)
package terminal
import (
"fmt"
"io"
"os"
)
// Writer provides an interface to write temporary and permanent messages to
// the terminal.
//
// The terminal is considered to be a dumb terminal if TERM==dumb, or if a
// terminal isn't detected on stdout/stderr (generally because it's a pipe or
// file). Dumb terminals will strip out all ANSI escape sequences, including
// colors.
type Writer interface {
// Print prints the string to the terminal, overwriting any current
// status being displayed.
//
// On a dumb terminal, the status messages will be kept.
Print(str string)
// Finish ensures that the output ends with a newline (preserving any
// current status line that is current displayed).
//
// This does nothing on dumb terminals.
Finish()
// Write implements the io.Writer interface. This is primarily so that
// the logger can use this interface to print to stderr without
// breaking the other semantics of this interface.
//
// Try to use any of the other functions if possible.
Write(p []byte) (n int, err error)
isSmartTerminal() bool
termWidth() (int, bool)
}
// NewWriter creates a new Writer based on the stdio and the TERM
// environment variable.
func NewWriter(stdio StdioInterface) Writer {
w := &writerImpl{
stdio: stdio,
}
return w
}
type writerImpl struct {
stdio StdioInterface
}
func (w *writerImpl) Print(str string) {
fmt.Fprint(w.stdio.Stdout(), str)
if len(str) == 0 || str[len(str)-1] != '\n' {
fmt.Fprint(w.stdio.Stdout(), "\n")
}
}
func (w *writerImpl) Finish() {}
func (w *writerImpl) Write(p []byte) (n int, err error) {
return w.stdio.Stdout().Write(p)
}
func (w *writerImpl) isSmartTerminal() bool {
return isSmartTerminal(w.stdio.Stdout())
}
func (w *writerImpl) termWidth() (int, bool) {
return termWidth(w.stdio.Stdout())
}
// StdioInterface represents a set of stdin/stdout/stderr Reader/Writers
type StdioInterface interface {
Stdin() io.Reader
Stdout() io.Writer
Stderr() io.Writer
}
// StdioImpl uses the OS stdin/stdout/stderr to implement StdioInterface
type StdioImpl struct{}
func (StdioImpl) Stdin() io.Reader { return os.Stdin }
func (StdioImpl) Stdout() io.Writer { return os.Stdout }
func (StdioImpl) Stderr() io.Writer { return os.Stderr }
var _ StdioInterface = StdioImpl{}
type customStdio struct {
stdin io.Reader
stdout io.Writer
stderr io.Writer
}
func NewCustomStdio(stdin io.Reader, stdout, stderr io.Writer) StdioInterface {
return customStdio{stdin, stdout, stderr}
}
func (c customStdio) Stdin() io.Reader { return c.stdin }
func (c customStdio) Stdout() io.Writer { return c.stdout }
func (c customStdio) Stderr() io.Writer { return c.stderr }
var _ StdioInterface = customStdio{}
|
