aboutsummaryrefslogtreecommitdiffstats
path: root/ui/build/util.go
blob: 37ac6b9a70ca64316f9dd8dcfa51a933c9236c74 (plain)
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
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
// Copyright 2017 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 build

import (
	"bytes"
	"io"
	"os"
	"path/filepath"
	"strings"
	"syscall"
	"unsafe"
)

// indexList finds the index of a string in a []string
func indexList(s string, list []string) int {
	for i, l := range list {
		if l == s {
			return i
		}
	}

	return -1
}

// inList determines whether a string is in a []string
func inList(s string, list []string) bool {
	return indexList(s, list) != -1
}

// ensureDirectoriesExist is a shortcut to os.MkdirAll, sending errors to the ctx logger.
func ensureDirectoriesExist(ctx Context, dirs ...string) {
	for _, dir := range dirs {
		err := os.MkdirAll(dir, 0777)
		if err != nil {
			ctx.Fatalf("Error creating %s: %q\n", dir, err)
		}
	}
}

// ensureEmptyFileExists ensures that the containing directory exists, and the
// specified file exists. If it doesn't exist, it will write an empty file.
func ensureEmptyFileExists(ctx Context, file string) {
	ensureDirectoriesExist(ctx, filepath.Dir(file))
	if _, err := os.Stat(file); os.IsNotExist(err) {
		f, err := os.Create(file)
		if err != nil {
			ctx.Fatalf("Error creating %s: %q\n", file, err)
		}
		f.Close()
	} else if err != nil {
		ctx.Fatalf("Error checking %s: %q\n", file, err)
	}
}

// singleUnquote is similar to strconv.Unquote, but can handle multi-character strings inside single quotes.
func singleUnquote(str string) (string, bool) {
	if len(str) < 2 || str[0] != '\'' || str[len(str)-1] != '\'' {
		return "", false
	}
	return str[1 : len(str)-1], true
}

// decodeKeyValue decodes a key=value string
func decodeKeyValue(str string) (string, string, bool) {
	idx := strings.IndexRune(str, '=')
	if idx == -1 {
		return "", "", false
	}
	return str[:idx], str[idx+1:], true
}

func isTerminal(w io.Writer) bool {
	if f, ok := w.(*os.File); ok {
		var termios syscall.Termios
		_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
			ioctlGetTermios, uintptr(unsafe.Pointer(&termios)),
			0, 0, 0)
		return err == 0
	}
	return false
}

func termWidth(w io.Writer) (int, bool) {
	if f, ok := w.(*os.File); ok {
		var winsize struct {
			ws_row, ws_column    uint16
			ws_xpixel, ws_ypixel uint16
		}
		_, _, err := syscall.Syscall6(syscall.SYS_IOCTL, f.Fd(),
			syscall.TIOCGWINSZ, uintptr(unsafe.Pointer(&winsize)),
			0, 0, 0)
		return int(winsize.ws_column), err == 0
	}
	return 0, false
}

// stripAnsiEscapes strips ANSI control codes from a byte array in place.
func stripAnsiEscapes(input []byte) []byte {
	// read represents the remaining part of input that needs to be processed.
	read := input
	// write represents where we should be writing in input.
	// It will share the same backing store as input so that we make our modifications
	// in place.
	write := input

	// advance will copy count bytes from read to write and advance those slices
	advance := func(write, read []byte, count int) ([]byte, []byte) {
		copy(write, read[:count])
		return write[count:], read[count:]
	}

	for {
		// Find the next escape sequence
		i := bytes.IndexByte(read, 0x1b)
		// If it isn't found, or if there isn't room for <ESC>[, finish
		if i == -1 || i+1 >= len(read) {
			copy(write, read)
			break
		}

		// Not a CSI code, continue searching
		if read[i+1] != '[' {
			write, read = advance(write, read, i+1)
			continue
		}

		// Found a CSI code, advance up to the <ESC>
		write, read = advance(write, read, i)

		// Find the end of the CSI code
		i = bytes.IndexFunc(read, func(r rune) bool {
			return (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z')
		})
		if i == -1 {
			// We didn't find the end of the code, just remove the rest
			i = len(read) - 1
		}

		// Strip off the end marker too
		i = i + 1

		// Skip the reader forward and reduce final length by that amount
		read = read[i:]
		input = input[:len(input)-i]
	}

	return input
}