File: flag.go

package info (click to toggle)
golang-github-urfave-cli-v2 2.2.0-3
  • links: PTS, VCS
  • area: main
  • in suites: bookworm, bullseye, sid
  • size: 6,376 kB
  • sloc: sh: 17; makefile: 4
file content (388 lines) | stat: -rw-r--r-- 9,639 bytes parent folder | download
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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
package cli

import (
	"flag"
	"fmt"
	"io/ioutil"
	"reflect"
	"regexp"
	"runtime"
	"strconv"
	"strings"
	"syscall"
	"time"
)

const defaultPlaceholder = "value"

var (
	slPfx = fmt.Sprintf("sl:::%d:::", time.Now().UTC().UnixNano())

	commaWhitespace = regexp.MustCompile("[, ]+.*")
)

// BashCompletionFlag enables bash-completion for all commands and subcommands
var BashCompletionFlag Flag = &BoolFlag{
	Name:   "generate-bash-completion",
	Hidden: true,
}

// VersionFlag prints the version for the application
var VersionFlag Flag = &BoolFlag{
	Name:    "version",
	Aliases: []string{"v"},
	Usage:   "print the version",
}

// HelpFlag prints the help for all commands and subcommands.
// Set to nil to disable the flag.  The subcommand
// will still be added unless HideHelp or HideHelpCommand is set to true.
var HelpFlag Flag = &BoolFlag{
	Name:    "help",
	Aliases: []string{"h"},
	Usage:   "show help",
}

// FlagStringer converts a flag definition to a string. This is used by help
// to display a flag.
var FlagStringer FlagStringFunc = stringifyFlag

// Serializer is used to circumvent the limitations of flag.FlagSet.Set
type Serializer interface {
	Serialize() string
}

// FlagNamePrefixer converts a full flag name and its placeholder into the help
// message flag prefix. This is used by the default FlagStringer.
var FlagNamePrefixer FlagNamePrefixFunc = prefixedNames

// FlagEnvHinter annotates flag help message with the environment variable
// details. This is used by the default FlagStringer.
var FlagEnvHinter FlagEnvHintFunc = withEnvHint

// FlagFileHinter annotates flag help message with the environment variable
// details. This is used by the default FlagStringer.
var FlagFileHinter FlagFileHintFunc = withFileHint

// FlagsByName is a slice of Flag.
type FlagsByName []Flag

func (f FlagsByName) Len() int {
	return len(f)
}

func (f FlagsByName) Less(i, j int) bool {
	if len(f[j].Names()) == 0 {
		return false
	} else if len(f[i].Names()) == 0 {
		return true
	}
	return lexicographicLess(f[i].Names()[0], f[j].Names()[0])
}

func (f FlagsByName) Swap(i, j int) {
	f[i], f[j] = f[j], f[i]
}

// Flag is a common interface related to parsing flags in cli.
// For more advanced flag parsing techniques, it is recommended that
// this interface be implemented.
type Flag interface {
	fmt.Stringer
	// Apply Flag settings to the given flag set
	Apply(*flag.FlagSet) error
	Names() []string
	IsSet() bool
}

// RequiredFlag is an interface that allows us to mark flags as required
// it allows flags required flags to be backwards compatible with the Flag interface
type RequiredFlag interface {
	Flag

	IsRequired() bool
}

// DocGenerationFlag is an interface that allows documentation generation for the flag
type DocGenerationFlag interface {
	Flag

	// TakesValue returns true if the flag takes a value, otherwise false
	TakesValue() bool

	// GetUsage returns the usage string for the flag
	GetUsage() string

	// GetValue returns the flags value as string representation and an empty
	// string if the flag takes no value at all.
	GetValue() string
}

func flagSet(name string, flags []Flag) (*flag.FlagSet, error) {
	set := flag.NewFlagSet(name, flag.ContinueOnError)

	for _, f := range flags {
		if err := f.Apply(set); err != nil {
			return nil, err
		}
	}
	set.SetOutput(ioutil.Discard)
	return set, nil
}

func visibleFlags(fl []Flag) []Flag {
	var visible []Flag
	for _, f := range fl {
		field := flagValue(f).FieldByName("Hidden")
		if !field.IsValid() || !field.Bool() {
			visible = append(visible, f)
		}
	}
	return visible
}

func prefixFor(name string) (prefix string) {
	if len(name) == 1 {
		prefix = "-"
	} else {
		prefix = "--"
	}

	return
}

// Returns the placeholder, if any, and the unquoted usage string.
func unquoteUsage(usage string) (string, string) {
	for i := 0; i < len(usage); i++ {
		if usage[i] == '`' {
			for j := i + 1; j < len(usage); j++ {
				if usage[j] == '`' {
					name := usage[i+1 : j]
					usage = usage[:i] + name + usage[j+1:]
					return name, usage
				}
			}
			break
		}
	}
	return "", usage
}

func prefixedNames(names []string, placeholder string) string {
	var prefixed string
	for i, name := range names {
		if name == "" {
			continue
		}

		prefixed += prefixFor(name) + name
		if placeholder != "" {
			prefixed += " " + placeholder
		}
		if i < len(names)-1 {
			prefixed += ", "
		}
	}
	return prefixed
}

func withEnvHint(envVars []string, str string) string {
	envText := ""
	if envVars != nil && len(envVars) > 0 {
		prefix := "$"
		suffix := ""
		sep := ", $"
		if runtime.GOOS == "windows" {
			prefix = "%"
			suffix = "%"
			sep = "%, %"
		}

		envText = fmt.Sprintf(" [%s%s%s]", prefix, strings.Join(envVars, sep), suffix)
	}
	return str + envText
}

func flagNames(name string, aliases []string) []string {
	var ret []string

	for _, part := range append([]string{name}, aliases...) {
		// v1 -> v2 migration warning zone:
		// Strip off anything after the first found comma or space, which
		// *hopefully* makes it a tiny bit more obvious that unexpected behavior is
		// caused by using the v1 form of stringly typed "Name".
		ret = append(ret, commaWhitespace.ReplaceAllString(part, ""))
	}

	return ret
}

func flagStringSliceField(f Flag, name string) []string {
	fv := flagValue(f)
	field := fv.FieldByName(name)

	if field.IsValid() {
		return field.Interface().([]string)
	}

	return []string{}
}

func withFileHint(filePath, str string) string {
	fileText := ""
	if filePath != "" {
		fileText = fmt.Sprintf(" [%s]", filePath)
	}
	return str + fileText
}

func flagValue(f Flag) reflect.Value {
	fv := reflect.ValueOf(f)
	for fv.Kind() == reflect.Ptr {
		fv = reflect.Indirect(fv)
	}
	return fv
}

func formatDefault(format string) string {
	return " (default: " + format + ")"
}

func stringifyFlag(f Flag) string {
	fv := flagValue(f)

	switch f := f.(type) {
	case *IntSliceFlag:
		return withEnvHint(flagStringSliceField(f, "EnvVars"),
			stringifyIntSliceFlag(f))
	case *Int64SliceFlag:
		return withEnvHint(flagStringSliceField(f, "EnvVars"),
			stringifyInt64SliceFlag(f))
	case *Float64SliceFlag:
		return withEnvHint(flagStringSliceField(f, "EnvVars"),
			stringifyFloat64SliceFlag(f))
	case *StringSliceFlag:
		return withEnvHint(flagStringSliceField(f, "EnvVars"),
			stringifyStringSliceFlag(f))
	}

	placeholder, usage := unquoteUsage(fv.FieldByName("Usage").String())

	needsPlaceholder := false
	defaultValueString := ""
	val := fv.FieldByName("Value")
	if val.IsValid() {
		needsPlaceholder = val.Kind() != reflect.Bool
		defaultValueString = fmt.Sprintf(formatDefault("%v"), val.Interface())

		if val.Kind() == reflect.String && val.String() != "" {
			defaultValueString = fmt.Sprintf(formatDefault("%q"), val.String())
		}
	}

	helpText := fv.FieldByName("DefaultText")
	if helpText.IsValid() && helpText.String() != "" {
		needsPlaceholder = val.Kind() != reflect.Bool
		defaultValueString = fmt.Sprintf(formatDefault("%s"), helpText.String())
	}

	if defaultValueString == formatDefault("") {
		defaultValueString = ""
	}

	if needsPlaceholder && placeholder == "" {
		placeholder = defaultPlaceholder
	}

	usageWithDefault := strings.TrimSpace(usage + defaultValueString)

	return withEnvHint(flagStringSliceField(f, "EnvVars"),
		fmt.Sprintf("%s\t%s", prefixedNames(f.Names(), placeholder), usageWithDefault))
}

func stringifyIntSliceFlag(f *IntSliceFlag) string {
	var defaultVals []string
	if f.Value != nil && len(f.Value.Value()) > 0 {
		for _, i := range f.Value.Value() {
			defaultVals = append(defaultVals, strconv.Itoa(i))
		}
	}

	return stringifySliceFlag(f.Usage, f.Names(), defaultVals)
}

func stringifyInt64SliceFlag(f *Int64SliceFlag) string {
	var defaultVals []string
	if f.Value != nil && len(f.Value.Value()) > 0 {
		for _, i := range f.Value.Value() {
			defaultVals = append(defaultVals, strconv.FormatInt(i, 10))
		}
	}

	return stringifySliceFlag(f.Usage, f.Names(), defaultVals)
}

func stringifyFloat64SliceFlag(f *Float64SliceFlag) string {
	var defaultVals []string

	if f.Value != nil && len(f.Value.Value()) > 0 {
		for _, i := range f.Value.Value() {
			defaultVals = append(defaultVals, strings.TrimRight(strings.TrimRight(fmt.Sprintf("%f", i), "0"), "."))
		}
	}

	return stringifySliceFlag(f.Usage, f.Names(), defaultVals)
}

func stringifyStringSliceFlag(f *StringSliceFlag) string {
	var defaultVals []string
	if f.Value != nil && len(f.Value.Value()) > 0 {
		for _, s := range f.Value.Value() {
			if len(s) > 0 {
				defaultVals = append(defaultVals, strconv.Quote(s))
			}
		}
	}

	return stringifySliceFlag(f.Usage, f.Names(), defaultVals)
}

func stringifySliceFlag(usage string, names, defaultVals []string) string {
	placeholder, usage := unquoteUsage(usage)
	if placeholder == "" {
		placeholder = defaultPlaceholder
	}

	defaultVal := ""
	if len(defaultVals) > 0 {
		defaultVal = fmt.Sprintf(formatDefault("%s"), strings.Join(defaultVals, ", "))
	}

	usageWithDefault := strings.TrimSpace(fmt.Sprintf("%s%s", usage, defaultVal))
	return fmt.Sprintf("%s\t%s", prefixedNames(names, placeholder), usageWithDefault)
}

func hasFlag(flags []Flag, fl Flag) bool {
	for _, existing := range flags {
		if fl == existing {
			return true
		}
	}

	return false
}

func flagFromEnvOrFile(envVars []string, filePath string) (val string, ok bool) {
	for _, envVar := range envVars {
		envVar = strings.TrimSpace(envVar)
		if val, ok := syscall.Getenv(envVar); ok {
			return val, true
		}
	}
	for _, fileVar := range strings.Split(filePath, ",") {
		if data, err := ioutil.ReadFile(fileVar); err == nil {
			return string(data), true
		}
	}
	return "", false
}