ref: 8a1c637c4494751046142e0ef345fce38fc1431b
dir: /tpl/strings/truncate.go/
// Copyright 2016 The Hugo Authors. All rights reserved. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. package strings import ( "errors" "html" "html/template" "regexp" "unicode" "unicode/utf8" "github.com/spf13/cast" ) var ( tagRE = regexp.MustCompile(`^<(/)?([^ ]+?)(?:(\s*/)| .*?)?>`) htmlSinglets = map[string]bool{ "br": true, "col": true, "link": true, "base": true, "img": true, "param": true, "area": true, "hr": true, "input": true, } ) type htmlTag struct { name string pos int openTag bool } // Truncate truncates a given string to the specified length. func (ns *Namespace) Truncate(a interface{}, options ...interface{}) (template.HTML, error) { length, err := cast.ToIntE(a) if err != nil { return "", err } var textParam interface{} var ellipsis string switch len(options) { case 0: return "", errors.New("truncate requires a length and a string") case 1: textParam = options[0] ellipsis = " …" case 2: textParam = options[1] ellipsis, err = cast.ToStringE(options[0]) if err != nil { return "", errors.New("ellipsis must be a string") } if _, ok := options[0].(template.HTML); !ok { ellipsis = html.EscapeString(ellipsis) } default: return "", errors.New("too many arguments passed to truncate") } if err != nil { return "", errors.New("text to truncate must be a string") } text, err := cast.ToStringE(textParam) if err != nil { return "", errors.New("text must be a string") } _, isHTML := textParam.(template.HTML) if utf8.RuneCountInString(text) <= length { if isHTML { return template.HTML(text), nil } return template.HTML(html.EscapeString(text)), nil } tags := []htmlTag{} var lastWordIndex, lastNonSpace, currentLen, endTextPos, nextTag int for i, r := range text { if i < nextTag { continue } if isHTML { // Make sure we keep tag of HTML tags slice := text[i:] m := tagRE.FindStringSubmatchIndex(slice) if len(m) > 0 && m[0] == 0 { nextTag = i + m[1] tagname := slice[m[4]:m[5]] lastWordIndex = lastNonSpace _, singlet := htmlSinglets[tagname] if !singlet && m[6] == -1 { tags = append(tags, htmlTag{name: tagname, pos: i, openTag: m[2] == -1}) } continue } } currentLen++ if unicode.IsSpace(r) { lastWordIndex = lastNonSpace } else if unicode.In(r, unicode.Han, unicode.Hangul, unicode.Hiragana, unicode.Katakana) { lastWordIndex = i } else { lastNonSpace = i + utf8.RuneLen(r) } if currentLen > length { if lastWordIndex == 0 { endTextPos = i } else { endTextPos = lastWordIndex } out := text[0:endTextPos] if isHTML { out += ellipsis // Close out any open HTML tags var currentTag *htmlTag for i := len(tags) - 1; i >= 0; i-- { tag := tags[i] if tag.pos >= endTextPos || currentTag != nil { if currentTag != nil && currentTag.name == tag.name { currentTag = nil } continue } if tag.openTag { out += ("</" + tag.name + ">") } else { currentTag = &tag } } return template.HTML(out), nil } return template.HTML(html.EscapeString(out) + ellipsis), nil } } if isHTML { return template.HTML(text), nil } return template.HTML(html.EscapeString(text)), nil }