// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package language
import (
"sort"
"strings"
)
// A Builder allows constructing a Tag from individual components.
// Its main user is Compose in the top-level language package.
type Builder struct {
Tag Tag
private string // the x extension
variants []string
extensions []string
}
// Make returns a new Tag from the current settings.
func (b *Builder) Make() Tag {
t := b.Tag
if len(b.extensions) > 0 || len(b.variants) > 0 {
sort.Sort(sortVariants(b.variants))
sort.Strings(b.extensions)
if b.private != "" {
b.extensions = append(b.extensions, b.private)
}
n := maxCoreSize + tokenLen(b.variants...) + tokenLen(b.extensions...)
buf := make([]byte, n)
p := t.genCoreBytes(buf)
t.pVariant = byte(p)
p += appendTokens(buf[p:], b.variants...)
t.pExt = uint16(p)
p += appendTokens(buf[p:], b.extensions...)
t.str = string(buf[:p])
// We may not always need to remake the string, but when or when not
// to do so is rather tricky.
scan := makeScanner(buf[:p])
t, _ = parse(&scan, "")
return t
} else if b.private != "" {
t.str = b.private
t.RemakeString()
}
return t
}
// SetTag copies all the settings from a given Tag. Any previously set values
// are discarded.
func (b *Builder) SetTag(t Tag) {
b.Tag.LangID = t.LangID
b.Tag.RegionID = t.RegionID
b.Tag.ScriptID = t.ScriptID
// TODO: optimize
b.variants = b.variants[:0]
if variants := t.Variants(); variants != "" {
for _, vr := range strings.Split(variants[1:], "-") {
b.variants = append(b.variants, vr)
}
}
b.extensions, b.private = b.extensions[:0], ""
for _, e := range t.Extensions() {
b.AddExt(e)
}
}
// AddExt adds extension e to the tag. e must be a valid extension as returned
// by Tag.Extension. If the extension already exists, it will be discarded,
// except for a -u extension, where non-existing key-type pairs will added.
func (b *Builder) AddExt(e string) {
if e[0] == 'x' {
if b.private == "" {
b.private = e
}
return
}
for i, s := range b.extensions {
if s[0] == e[0] {
if e[0] == 'u' {
b.extensions[i] += e[1:]
}
return
}
}
b.extensions = append(b.extensions, e)
}
// SetExt sets the extension e to the tag. e must be a valid extension as
// returned by Tag.Extension. If the extension already exists, it will be
// overwritten, except for a -u extension, where the individual key-type pairs
// will be set.
func (b *Builder) SetExt(e string) {
if e[0] == 'x' {
b.private = e
return
}
for i, s := range b.extensions {
if s[0] == e[0] {
if e[0] == 'u' {
b.extensions[i] = e + s[1:]
} else {
b.extensions[i] = e
}
return
}
}
b.extensions = append(b.extensions, e)
}
// AddVariant adds any number of variants.
func (b *Builder) AddVariant(v ...string) {
for _, v := range v {
if v != "" {
b.variants = append(b.variants, v)
}
}
}
// ClearVariants removes any variants previously added, including those
// copied from a Tag in SetTag.
func (b *Builder) ClearVariants() {
b.variants = b.variants[:0]
}
// ClearExtensions removes any extensions previously added, including those
// copied from a Tag in SetTag.
func (b *Builder) ClearExtensions() {
b.private = ""
b.extensions = b.extensions[:0]
}
func tokenLen(token ...string) (n int) {
for _, t := range token {
n += len(t) + 1
}
return
}
func appendTokens(b []byte, token ...string) int {
p := 0
for _, t := range token {
b[p] = '-'
copy(b[p+1:], t)
p += 1 + len(t)
}
return p
}
type sortVariants []string
func (s sortVariants) Len() int {
return len(s)
}
func (s sortVariants) Swap(i, j int) {
s[j], s[i] = s[i], s[j]
}
func (s sortVariants) Less(i, j int) bool {
return variantIndex[s[i]] < variantIndex[s[j]]
}
