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moby--moby/pkg/stringutils/stringutils.go
allencloud 7c3657065c change minor mistake of spelling
Signed-off-by: allencloud <allen.sun@daocloud.io>
2016-12-20 21:05:19 +08:00

101 lines
2.4 KiB
Go

// Package stringutils provides helper functions for dealing with strings.
package stringutils
import (
"bytes"
"math/rand"
"strings"
"github.com/docker/docker/pkg/random"
)
// GenerateRandomAlphaOnlyString generates an alphabetical random string with length n.
func GenerateRandomAlphaOnlyString(n int) string {
// make a really long string
letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
b := make([]byte, n)
for i := range b {
b[i] = letters[random.Rand.Intn(len(letters))]
}
return string(b)
}
// GenerateRandomASCIIString generates an ASCII random string with length n.
func GenerateRandomASCIIString(n int) string {
chars := "abcdefghijklmnopqrstuvwxyz" +
"ABCDEFGHIJKLMNOPQRSTUVWXYZ" +
"~!@#$%^&*()-_+={}[]\\|<,>.?/\"';:` "
res := make([]byte, n)
for i := 0; i < n; i++ {
res[i] = chars[rand.Intn(len(chars))]
}
return string(res)
}
// Ellipsis truncates a string to fit within maxlen, and appends ellipsis (...).
// For maxlen of 3 and lower, no ellipsis is appended.
func Ellipsis(s string, maxlen int) string {
r := []rune(s)
if len(r) <= maxlen {
return s
}
if maxlen <= 3 {
return string(r[:maxlen])
}
return string(r[:maxlen-3]) + "..."
}
// Truncate truncates a string to maxlen.
func Truncate(s string, maxlen int) string {
r := []rune(s)
if len(r) <= maxlen {
return s
}
return string(r[:maxlen])
}
// InSlice tests whether a string is contained in a slice of strings or not.
// Comparison is case insensitive
func InSlice(slice []string, s string) bool {
for _, ss := range slice {
if strings.ToLower(s) == strings.ToLower(ss) {
return true
}
}
return false
}
func quote(word string, buf *bytes.Buffer) {
// Bail out early for "simple" strings
if word != "" && !strings.ContainsAny(word, "\\'\"`${[|&;<>()~*?! \t\n") {
buf.WriteString(word)
return
}
buf.WriteString("'")
for i := 0; i < len(word); i++ {
b := word[i]
if b == '\'' {
// Replace literal ' with a close ', a \', and an open '
buf.WriteString("'\\''")
} else {
buf.WriteByte(b)
}
}
buf.WriteString("'")
}
// ShellQuoteArguments takes a list of strings and escapes them so they will be
// handled right when passed as arguments to a program via a shell
func ShellQuoteArguments(args []string) string {
var buf bytes.Buffer
for i, arg := range args {
if i != 0 {
buf.WriteByte(' ')
}
quote(arg, &buf)
}
return buf.String()
}