Checking in vendor folder for ease of using go get.

vendor/golang.org/x/text/secure/precis/options.go

@@ -0,0 +1,157 @@
+// 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
+	repeat        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
+	}
+	repeat = func(o *options) {
+		o.repeat = 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
+	}
+}