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
|
// Copyright 2018 The Bazel Authors. 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 flagfile installs a -flagfile command line flag.
// This package is only imported for the side effect of installing the flag
package flagfile
import (
"bufio"
"flag"
"fmt"
"io"
"os"
"strings"
)
type flagFile string
func (f *flagFile) String() string {
return string(*f)
}
func (f *flagFile) Get() interface{} {
return string(*f)
}
func (f *flagFile) Set(fn string) error {
file, err := os.Open(fn)
if err != nil {
return fmt.Errorf("error parsing flagfile %s: %v", fn, err)
}
defer file.Close()
fMap, err := parseFlags(bufio.NewReader(file))
if err != nil {
return err
}
for k, v := range fMap {
flag.Set(k, v)
}
return nil
}
// parseFlags parses the contents is a naive flag file parser.
func parseFlags(r *bufio.Reader) (map[string]string, error) {
fMap := make(map[string]string)
eof := false
for !eof {
line, err := r.ReadString('\n')
if err != nil && err != io.EOF {
return nil, err
}
if err == io.EOF {
eof = true
}
line = strings.TrimSpace(line)
if line == "" {
continue
}
// When Bazel is used to create flag files, it may create entries that are wrapped within
// quotations '--a=b'. Verify that it is balanced and strip first and last quotation.
if strings.HasPrefix(line, "'") || strings.HasPrefix(line, "\"") {
if !strings.HasSuffix(line, line[:1]) {
return nil, fmt.Errorf("error parsing flags, found unbalanced quotation marks around flag entry: %s", line)
}
line = line[1 : len(line)-1]
}
// Check that the flag has at least 1 "-" but no more than 2 ("-a" or "--a").
if !strings.HasPrefix(line, "-") || strings.HasPrefix(line, "---") {
return nil, fmt.Errorf("error parsing flags, expected flag start definition ('-' or '--') but, got: %s", line)
}
split := strings.SplitN(strings.TrimLeft(line, "-"), "=", 2)
k := split[0]
if len(split) == 2 {
fMap[k] = split[1]
continue
}
v, err := parseFlagValue(r)
if err != nil {
return nil, fmt.Errorf("error parsing flag value, got: %v", err)
}
fMap[k] = v
}
return fMap, nil
}
func parseFlagValue(r *bufio.Reader) (string, error) {
pBytes, err := r.Peek(2)
if err != nil && err != io.EOF {
return "", err
}
peeked := string(pBytes)
// If the next line starts with "-", "'-" or '"-' assume it is the beginning of a new flag definition.
if strings.HasPrefix(peeked, "-") || peeked == "'-" || peeked == "\"-" {
return "", nil
}
// Next line contains the flag value.
line, err := r.ReadString('\n')
if err != nil && err != io.EOF {
return "", err
}
return strings.TrimSpace(line), nil
}
func init() {
flag.Var(new(flagFile), "flagfile", "Path to flagfile containing flag values, --key=val on each line")
}
|
