blob: 486606f3768dbaae1c21705435a25f9f3043bbfc [file] [log] [blame]
package buildutil
// This logic was copied from stringsFlag from $GOROOT/src/cmd/go/build.go.
import "fmt"
const TagsFlagDoc = "a list of `build tags` to consider satisfied during the build. " +
"For more information about build tags, see the description of " +
"build constraints in the documentation for the go/build package"
// TagsFlag is an implementation of the flag.Value and flag.Getter interfaces that parses
// a flag value in the same manner as go build's -tags flag and
// populates a []string slice.
//
// See $GOROOT/src/go/build/doc.go for description of build tags.
// See $GOROOT/src/cmd/go/doc.go for description of 'go build -tags' flag.
//
// Example:
// flag.Var((*buildutil.TagsFlag)(&build.Default.BuildTags), "tags", buildutil.TagsFlagDoc)
type TagsFlag []string
func (v *TagsFlag) Set(s string) error {
var err error
*v, err = splitQuotedFields(s)
if *v == nil {
*v = []string{}
}
return err
}
func (v *TagsFlag) Get() interface{} { return *v }
func splitQuotedFields(s string) ([]string, error) {
// Split fields allowing '' or "" around elements.
// Quotes further inside the string do not count.
var f []string
for len(s) > 0 {
for len(s) > 0 && isSpaceByte(s[0]) {
s = s[1:]
}
if len(s) == 0 {
break
}
// Accepted quoted string. No unescaping inside.
if s[0] == '"' || s[0] == '\'' {
quote := s[0]
s = s[1:]
i := 0
for i < len(s) && s[i] != quote {
i++
}
if i >= len(s) {
return nil, fmt.Errorf("unterminated %c string", quote)
}
f = append(f, s[:i])
s = s[i+1:]
continue
}
i := 0
for i < len(s) && !isSpaceByte(s[i]) {
i++
}
f = append(f, s[:i])
s = s[i:]
}
return f, nil
}
func (v *TagsFlag) String() string {
return "<tagsFlag>"
}
func isSpaceByte(c byte) bool {
return c == ' ' || c == '\t' || c == '\n' || c == '\r'
}