153 lines
4 KiB
Go
153 lines
4 KiB
Go
// Copyright 2015 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 precis
|
|
|
|
import (
|
|
"golang.org/x/text/cases"
|
|
"golang.org/x/text/language"
|
|
"golang.org/x/text/runes"
|
|
"golang.org/x/text/transform"
|
|
"golang.org/x/text/unicode/norm"
|
|
)
|
|
|
|
// An Option is used to define the behavior and rules of a Profile.
|
|
type Option func(*options)
|
|
|
|
type options struct {
|
|
// Preparation options
|
|
foldWidth bool
|
|
|
|
// Enforcement options
|
|
asciiLower bool
|
|
cases transform.SpanningTransformer
|
|
disallow runes.Set
|
|
norm transform.SpanningTransformer
|
|
additional []func() transform.SpanningTransformer
|
|
width transform.SpanningTransformer
|
|
disallowEmpty bool
|
|
bidiRule bool
|
|
|
|
// Comparison options
|
|
ignorecase bool
|
|
}
|
|
|
|
func getOpts(o ...Option) (res options) {
|
|
for _, f := range o {
|
|
f(&res)
|
|
}
|
|
// Using a SpanningTransformer, instead of norm.Form prevents an allocation
|
|
// down the road.
|
|
if res.norm == nil {
|
|
res.norm = norm.NFC
|
|
}
|
|
return
|
|
}
|
|
|
|
var (
|
|
// The IgnoreCase option causes the profile to perform a case insensitive
|
|
// comparison during the PRECIS comparison step.
|
|
IgnoreCase Option = ignoreCase
|
|
|
|
// The FoldWidth option causes the profile to map non-canonical wide and
|
|
// narrow variants to their decomposition mapping. This is useful for
|
|
// profiles that are based on the identifier class which would otherwise
|
|
// disallow such characters.
|
|
FoldWidth Option = foldWidth
|
|
|
|
// The DisallowEmpty option causes the enforcement step to return an error if
|
|
// the resulting string would be empty.
|
|
DisallowEmpty Option = disallowEmpty
|
|
|
|
// The BidiRule option causes the Bidi Rule defined in RFC 5893 to be
|
|
// applied.
|
|
BidiRule Option = bidiRule
|
|
)
|
|
|
|
var (
|
|
ignoreCase = func(o *options) {
|
|
o.ignorecase = true
|
|
}
|
|
foldWidth = func(o *options) {
|
|
o.foldWidth = true
|
|
}
|
|
disallowEmpty = func(o *options) {
|
|
o.disallowEmpty = true
|
|
}
|
|
bidiRule = func(o *options) {
|
|
o.bidiRule = true
|
|
}
|
|
)
|
|
|
|
// TODO: move this logic to package transform
|
|
|
|
type spanWrap struct{ transform.Transformer }
|
|
|
|
func (s spanWrap) Span(src []byte, atEOF bool) (n int, err error) {
|
|
return 0, transform.ErrEndOfSpan
|
|
}
|
|
|
|
// TODO: allow different types? For instance:
|
|
// func() transform.Transformer
|
|
// func() transform.SpanningTransformer
|
|
// func([]byte) bool // validation only
|
|
//
|
|
// Also, would be great if we could detect if a transformer is reentrant.
|
|
|
|
// The AdditionalMapping option defines the additional mapping rule for the
|
|
// Profile by applying Transformer's in sequence.
|
|
func AdditionalMapping(t ...func() transform.Transformer) Option {
|
|
return func(o *options) {
|
|
for _, f := range t {
|
|
sf := func() transform.SpanningTransformer {
|
|
return f().(transform.SpanningTransformer)
|
|
}
|
|
if _, ok := f().(transform.SpanningTransformer); !ok {
|
|
sf = func() transform.SpanningTransformer {
|
|
return spanWrap{f()}
|
|
}
|
|
}
|
|
o.additional = append(o.additional, sf)
|
|
}
|
|
}
|
|
}
|
|
|
|
// The Norm option defines a Profile's normalization rule. Defaults to NFC.
|
|
func Norm(f norm.Form) Option {
|
|
return func(o *options) {
|
|
o.norm = f
|
|
}
|
|
}
|
|
|
|
// The FoldCase option defines a Profile's case mapping rule. Options can be
|
|
// provided to determine the type of case folding used.
|
|
func FoldCase(opts ...cases.Option) Option {
|
|
return func(o *options) {
|
|
o.asciiLower = true
|
|
o.cases = cases.Fold(opts...)
|
|
}
|
|
}
|
|
|
|
// The LowerCase option defines a Profile's case mapping rule. Options can be
|
|
// provided to determine the type of case folding used.
|
|
func LowerCase(opts ...cases.Option) Option {
|
|
return func(o *options) {
|
|
o.asciiLower = true
|
|
if len(opts) == 0 {
|
|
o.cases = cases.Lower(language.Und, cases.HandleFinalSigma(false))
|
|
return
|
|
}
|
|
|
|
opts = append([]cases.Option{cases.HandleFinalSigma(false)}, opts...)
|
|
o.cases = cases.Lower(language.Und, opts...)
|
|
}
|
|
}
|
|
|
|
// The Disallow option further restricts a Profile's allowed characters beyond
|
|
// what is disallowed by the underlying string class.
|
|
func Disallow(set runes.Set) Option {
|
|
return func(o *options) {
|
|
o.disallow = set
|
|
}
|
|
}
|