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sections.go
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sections.go
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package search
import (
"github.com/russross/blackfriday/v2"
"github.com/sourcegraph/docsite/internal/search/query"
"github.com/sourcegraph/docsite/markdown"
)
type SectionResult struct {
ID string // the URL fragment (without "#") of the section, or empty if in the first section
IDStack []string // the stack of section IDs
Title string // the section title
TitleStack []string // the stack of section titles
Excerpts []string // the match excerpt
}
func documentSectionResults(data string, query query.Query) ([]SectionResult, error) {
type stackEntry struct {
id string
title string
level int
}
stack := []stackEntry{{}}
cur := func() stackEntry { return stack[len(stack)-1] }
ast := markdown.NewParser(markdown.NewBfRenderer()).Parse([]byte(data))
markdown.SetHeadingIDs(ast)
var results []SectionResult
addResult := func(excerpts []string) {
stackIDs := make([]string, len(stack))
stackTitles := make([]string, len(stack))
for i, e := range stack {
stackIDs[i] = e.id
stackTitles[i] = e.title
}
e := cur()
// If last section result was in the same section, just append the excerpt instead of
// creating a new section result.
if len(results) > 0 {
last := results[len(results)-1]
if lastResultIsSameSection := last.ID == e.id; lastResultIsSameSection {
last.Excerpts = append(last.Excerpts, excerpts...)
return
}
}
results = append(results, SectionResult{
ID: e.id,
IDStack: stackIDs,
Title: e.title,
TitleStack: stackTitles,
Excerpts: excerpts,
})
}
ast.Walk(func(node *blackfriday.Node, entering bool) blackfriday.WalkStatus {
if entering && node.Type == blackfriday.Heading {
for node.Level <= cur().level {
stack = stack[:len(stack)-1]
}
// For the document top title heading, use the empty ID.
var id string
if !markdown.IsDocumentTopTitleHeadingNode(node) {
id = node.HeadingID
}
stack = append(stack, stackEntry{
id: id,
title: string(markdown.RenderText(node)),
level: node.Level,
})
}
if entering && (node.Type == blackfriday.Paragraph || node.Type == blackfriday.Item || node.Type == blackfriday.Heading || node.Type == blackfriday.BlockQuote || node.Type == blackfriday.Code) {
text := string(markdown.RenderText(node))
if matches := query.FindAllIndex(text); len(matches) > 0 {
// Don't include excerpts for heading because all of the heading is considered the
// match.
var excerpts []string
if node.Type != blackfriday.Heading {
excerpts = make([]string, len(matches))
for i, match := range matches {
const excerptMaxLength = 220
excerpts[i] = excerpt(text, match[0], match[1], excerptMaxLength)
}
}
// Remove the previous heading-only match for the same section, if any. A match with
// an excerpt is strictly better than one without.
if len(results) > 0 {
last := results[len(results)-1]
if last.ID == cur().id && len(last.Excerpts) == 0 {
results = results[:len(results)-1]
}
}
addResult(excerpts)
return blackfriday.SkipChildren
}
}
return blackfriday.GoToNext
})
return results, nil
}