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// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.
package markdown
import (
"strings"
)
type continuation struct {
Indentation int
Remaining Range
}
type Block interface {
Continuation(indentation int, r Range) *continuation
AddLine(indentation int, r Range) bool
Close()
AllowsBlockStarts() bool
HasTrailingBlankLine() bool
}
type blockBase struct{}
func (*blockBase) AddLine(indentation int, r Range) bool { return false }
func (*blockBase) Close() {}
func (*blockBase) AllowsBlockStarts() bool { return true }
func (*blockBase) HasTrailingBlankLine() bool { return false }
type ContainerBlock interface {
Block
AddChild(openBlocks []Block) []Block
}
type Range struct {
Position int
End int
}
func closeBlocks(blocks []Block, referenceDefinitions []*ReferenceDefinition) []*ReferenceDefinition {
for _, block := range blocks {
block.Close()
if p, ok := block.(*Paragraph); ok && len(p.ReferenceDefinitions) > 0 {
referenceDefinitions = append(referenceDefinitions, p.ReferenceDefinitions...)
}
}
return referenceDefinitions
}
func ParseBlocks(markdown string, lines []Line) (*Document, []*ReferenceDefinition) {
document := &Document{}
var referenceDefinitions []*ReferenceDefinition
openBlocks := []Block{document}
for _, line := range lines {
r := line.Range
lastMatchIndex := 0
indentation, indentationBytes := countIndentation(markdown, r)
r = Range{r.Position + indentationBytes, r.End}
for i, block := range openBlocks {
if continuation := block.Continuation(indentation, r); continuation != nil {
indentation = continuation.Indentation
r = continuation.Remaining
additionalIndentation, additionalIndentationBytes := countIndentation(markdown, r)
r = Range{r.Position + additionalIndentationBytes, r.End}
indentation += additionalIndentation
lastMatchIndex = i
} else {
break
}
}
if openBlocks[lastMatchIndex].AllowsBlockStarts() {
if newBlocks := blockStart(markdown, indentation, r, openBlocks[:lastMatchIndex+1], openBlocks[lastMatchIndex+1:]); newBlocks != nil {
didAdd := false
for i := lastMatchIndex; i >= 0; i-- {
if container, ok := openBlocks[i].(ContainerBlock); ok {
if addedBlocks := container.AddChild(newBlocks); addedBlocks != nil {
referenceDefinitions = closeBlocks(openBlocks[i+1:], referenceDefinitions)
openBlocks = openBlocks[:i+1]
openBlocks = append(openBlocks, addedBlocks...)
didAdd = true
break
}
}
}
if didAdd {
continue
}
}
}
isBlank := strings.TrimSpace(markdown[r.Position:r.End]) == ""
if paragraph, ok := openBlocks[len(openBlocks)-1].(*Paragraph); ok && !isBlank {
paragraph.Text = append(paragraph.Text, r)
continue
}
referenceDefinitions = closeBlocks(openBlocks[lastMatchIndex+1:], referenceDefinitions)
openBlocks = openBlocks[:lastMatchIndex+1]
if openBlocks[lastMatchIndex].AddLine(indentation, r) {
continue
}
if paragraph := newParagraph(markdown, r); paragraph != nil {
for i := lastMatchIndex; i >= 0; i-- {
if container, ok := openBlocks[i].(ContainerBlock); ok {
if newBlocks := container.AddChild([]Block{paragraph}); newBlocks != nil {
referenceDefinitions = closeBlocks(openBlocks[i+1:], referenceDefinitions)
openBlocks = openBlocks[:i+1]
openBlocks = append(openBlocks, newBlocks...)
break
}
}
}
}
}
referenceDefinitions = closeBlocks(openBlocks, referenceDefinitions)
return document, referenceDefinitions
}
func blockStart(markdown string, indentation int, r Range, matchedBlocks, unmatchedBlocks []Block) []Block {
if r.Position >= r.End {
return nil
}
if start := blockQuoteStart(markdown, indentation, r); start != nil {
return start
} else if start := listStart(markdown, indentation, r, matchedBlocks, unmatchedBlocks); start != nil {
return start
} else if start := indentedCodeStart(markdown, indentation, r, matchedBlocks, unmatchedBlocks); start != nil {
return start
} else if start := fencedCodeStart(markdown, indentation, r); start != nil {
return start
}
return nil
}
func blockStartOrParagraph(markdown string, indentation int, r Range, matchedBlocks, unmatchedBlocks []Block) []Block {
if start := blockStart(markdown, indentation, r, matchedBlocks, unmatchedBlocks); start != nil {
return start
}
if paragraph := newParagraph(markdown, r); paragraph != nil {
return []Block{paragraph}
}
return nil
}
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