149 lines
3.0 KiB
Go
149 lines
3.0 KiB
Go
// Copyright 2019 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package tableofcontents
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import (
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"strings"
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)
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type Headers []Header
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type Header struct {
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ID string
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Text string
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Headers Headers
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}
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func (h Header) IsZero() bool {
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return h.ID == "" && h.Text == ""
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}
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type Root struct {
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Headers Headers
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}
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func (toc *Root) AddAt(h Header, y, x int) {
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for i := len(toc.Headers); i <= y; i++ {
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toc.Headers = append(toc.Headers, Header{})
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}
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if x == 0 {
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toc.Headers[y] = h
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return
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}
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header := &toc.Headers[y]
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for i := 1; i < x; i++ {
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if len(header.Headers) == 0 {
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header.Headers = append(header.Headers, Header{})
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}
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header = &header.Headers[len(header.Headers)-1]
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}
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header.Headers = append(header.Headers, h)
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}
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func (toc Root) ToHTML(startLevel, stopLevel int) string {
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b := &tocBuilder{
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s: strings.Builder{},
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h: toc.Headers,
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startLevel: startLevel,
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stopLevel: stopLevel,
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}
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b.Build()
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return b.s.String()
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}
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type tocBuilder struct {
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s strings.Builder
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h Headers
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startLevel int
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stopLevel int
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}
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func (b *tocBuilder) Build() {
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b.buildHeaders2(b.h)
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}
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func (b *tocBuilder) buildHeaders2(h Headers) {
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b.s.WriteString("<nav id=\"TableOfContents\">")
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b.buildHeaders(1, 0, b.h)
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b.s.WriteString("</nav>")
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}
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func (b *tocBuilder) buildHeaders(level, indent int, h Headers) {
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if level < b.startLevel {
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for _, h := range h {
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b.buildHeaders(level+1, indent, h.Headers)
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}
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return
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}
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if b.stopLevel != -1 && level > b.stopLevel {
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return
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}
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hasChildren := len(h) > 0
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if hasChildren {
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b.s.WriteString("\n")
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b.indent(indent + 1)
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b.s.WriteString("<ul>\n")
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}
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for _, h := range h {
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b.buildHeader(level+1, indent+2, h)
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}
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if hasChildren {
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b.indent(indent + 1)
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b.s.WriteString("</ul>")
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b.s.WriteString("\n")
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b.indent(indent)
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}
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}
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func (b *tocBuilder) buildHeader(level, indent int, h Header) {
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b.indent(indent)
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b.s.WriteString("<li>")
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if !h.IsZero() {
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b.s.WriteString("<a href=\"#" + h.ID + "\">" + h.Text + "</a>")
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}
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b.buildHeaders(level, indent, h.Headers)
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b.s.WriteString("</li>\n")
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}
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func (b *tocBuilder) indent(n int) {
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for i := 0; i < n; i++ {
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b.s.WriteString(" ")
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}
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}
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var DefaultConfig = Config{
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StartLevel: 2,
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EndLevel: 3,
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}
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type Config struct {
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// Heading start level to include in the table of contents, starting
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// at h1 (inclusive).
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StartLevel int
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// Heading end level, inclusive, to include in the table of contents.
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// Default is 3, a value of -1 will include everything.
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EndLevel int
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}
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