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moby--moby/pkg/useragent/useragent.go

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// Package useragent provides helper functions to pack
// version information into a single User-Agent header.
package useragent
import (
"strings"
)
// VersionInfo is used to model UserAgent versions.
type VersionInfo struct {
Name string
Version string
}
func (vi *VersionInfo) isValid() bool {
const stopChars = " \t\r\n/"
name := vi.Name
vers := vi.Version
if len(name) == 0 || strings.ContainsAny(name, stopChars) {
return false
}
if len(vers) == 0 || strings.ContainsAny(vers, stopChars) {
return false
}
return true
}
// AppendVersions converts versions to a string and appends the string to the string base.
//
// Each VersionInfo will be converted to a string in the format of
// "product/version", where the "product" is get from the name field, while
// version is get from the version field. Several pieces of version information
// will be concatenated and separated by space.
//
// Example:
// AppendVersions("base", VersionInfo{"foo", "1.0"}, VersionInfo{"bar", "2.0"})
// results in "base foo/1.0 bar/2.0".
func AppendVersions(base string, versions ...VersionInfo) string {
if len(versions) == 0 {
return base
}
verstrs := make([]string, 0, 1+len(versions))
if len(base) > 0 {
verstrs = append(verstrs, base)
}
for _, v := range versions {
if !v.isValid() {
continue
}
verstrs = append(verstrs, v.Name+"/"+v.Version)
}
return strings.Join(verstrs, " ")
}