maubot/vendor/gopkg.in/russross/blackfriday.v2/block.go
Tulir Asokan e26fc65cd0 Add dep
2018-07-06 16:08:50 +03:00

1550 lines
32 KiB
Go

//
// Blackfriday Markdown Processor
// Available at http://github.com/russross/blackfriday
//
// Copyright © 2011 Russ Ross <russ@russross.com>.
// Distributed under the Simplified BSD License.
// See README.md for details.
//
//
// Functions to parse block-level elements.
//
package blackfriday
import (
"bytes"
"html"
"regexp"
"github.com/shurcooL/sanitized_anchor_name"
)
const (
charEntity = "&(?:#x[a-f0-9]{1,8}|#[0-9]{1,8}|[a-z][a-z0-9]{1,31});"
escapable = "[!\"#$%&'()*+,./:;<=>?@[\\\\\\]^_`{|}~-]"
)
var (
reBackslashOrAmp = regexp.MustCompile("[\\&]")
reEntityOrEscapedChar = regexp.MustCompile("(?i)\\\\" + escapable + "|" + charEntity)
)
// Parse block-level data.
// Note: this function and many that it calls assume that
// the input buffer ends with a newline.
func (p *Markdown) block(data []byte) {
// this is called recursively: enforce a maximum depth
if p.nesting >= p.maxNesting {
return
}
p.nesting++
// parse out one block-level construct at a time
for len(data) > 0 {
// prefixed heading:
//
// # Heading 1
// ## Heading 2
// ...
// ###### Heading 6
if p.isPrefixHeading(data) {
data = data[p.prefixHeading(data):]
continue
}
// block of preformatted HTML:
//
// <div>
// ...
// </div>
if data[0] == '<' {
if i := p.html(data, true); i > 0 {
data = data[i:]
continue
}
}
// title block
//
// % stuff
// % more stuff
// % even more stuff
if p.extensions&Titleblock != 0 {
if data[0] == '%' {
if i := p.titleBlock(data, true); i > 0 {
data = data[i:]
continue
}
}
}
// blank lines. note: returns the # of bytes to skip
if i := p.isEmpty(data); i > 0 {
data = data[i:]
continue
}
// indented code block:
//
// func max(a, b int) int {
// if a > b {
// return a
// }
// return b
// }
if p.codePrefix(data) > 0 {
data = data[p.code(data):]
continue
}
// fenced code block:
//
// ``` go
// func fact(n int) int {
// if n <= 1 {
// return n
// }
// return n * fact(n-1)
// }
// ```
if p.extensions&FencedCode != 0 {
if i := p.fencedCodeBlock(data, true); i > 0 {
data = data[i:]
continue
}
}
// horizontal rule:
//
// ------
// or
// ******
// or
// ______
if p.isHRule(data) {
p.addBlock(HorizontalRule, nil)
var i int
for i = 0; i < len(data) && data[i] != '\n'; i++ {
}
data = data[i:]
continue
}
// block quote:
//
// > A big quote I found somewhere
// > on the web
if p.quotePrefix(data) > 0 {
data = data[p.quote(data):]
continue
}
// table:
//
// Name | Age | Phone
// ------|-----|---------
// Bob | 31 | 555-1234
// Alice | 27 | 555-4321
if p.extensions&Tables != 0 {
if i := p.table(data); i > 0 {
data = data[i:]
continue
}
}
// an itemized/unordered list:
//
// * Item 1
// * Item 2
//
// also works with + or -
if p.uliPrefix(data) > 0 {
data = data[p.list(data, 0):]
continue
}
// a numbered/ordered list:
//
// 1. Item 1
// 2. Item 2
if p.oliPrefix(data) > 0 {
data = data[p.list(data, ListTypeOrdered):]
continue
}
// definition lists:
//
// Term 1
// : Definition a
// : Definition b
//
// Term 2
// : Definition c
if p.extensions&DefinitionLists != 0 {
if p.dliPrefix(data) > 0 {
data = data[p.list(data, ListTypeDefinition):]
continue
}
}
// anything else must look like a normal paragraph
// note: this finds underlined headings, too
data = data[p.paragraph(data):]
}
p.nesting--
}
func (p *Markdown) addBlock(typ NodeType, content []byte) *Node {
p.closeUnmatchedBlocks()
container := p.addChild(typ, 0)
container.content = content
return container
}
func (p *Markdown) isPrefixHeading(data []byte) bool {
if data[0] != '#' {
return false
}
if p.extensions&SpaceHeadings != 0 {
level := 0
for level < 6 && level < len(data) && data[level] == '#' {
level++
}
if level == len(data) || data[level] != ' ' {
return false
}
}
return true
}
func (p *Markdown) prefixHeading(data []byte) int {
level := 0
for level < 6 && level < len(data) && data[level] == '#' {
level++
}
i := skipChar(data, level, ' ')
end := skipUntilChar(data, i, '\n')
skip := end
id := ""
if p.extensions&HeadingIDs != 0 {
j, k := 0, 0
// find start/end of heading id
for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
}
for k = j + 1; k < end && data[k] != '}'; k++ {
}
// extract heading id iff found
if j < end && k < end {
id = string(data[j+2 : k])
end = j
skip = k + 1
for end > 0 && data[end-1] == ' ' {
end--
}
}
}
for end > 0 && data[end-1] == '#' {
if isBackslashEscaped(data, end-1) {
break
}
end--
}
for end > 0 && data[end-1] == ' ' {
end--
}
if end > i {
if id == "" && p.extensions&AutoHeadingIDs != 0 {
id = sanitized_anchor_name.Create(string(data[i:end]))
}
block := p.addBlock(Heading, data[i:end])
block.HeadingID = id
block.Level = level
}
return skip
}
func (p *Markdown) isUnderlinedHeading(data []byte) int {
// test of level 1 heading
if data[0] == '=' {
i := skipChar(data, 1, '=')
i = skipChar(data, i, ' ')
if i < len(data) && data[i] == '\n' {
return 1
}
return 0
}
// test of level 2 heading
if data[0] == '-' {
i := skipChar(data, 1, '-')
i = skipChar(data, i, ' ')
if i < len(data) && data[i] == '\n' {
return 2
}
return 0
}
return 0
}
func (p *Markdown) titleBlock(data []byte, doRender bool) int {
if data[0] != '%' {
return 0
}
splitData := bytes.Split(data, []byte("\n"))
var i int
for idx, b := range splitData {
if !bytes.HasPrefix(b, []byte("%")) {
i = idx // - 1
break
}
}
data = bytes.Join(splitData[0:i], []byte("\n"))
consumed := len(data)
data = bytes.TrimPrefix(data, []byte("% "))
data = bytes.Replace(data, []byte("\n% "), []byte("\n"), -1)
block := p.addBlock(Heading, data)
block.Level = 1
block.IsTitleblock = true
return consumed
}
func (p *Markdown) html(data []byte, doRender bool) int {
var i, j int
// identify the opening tag
if data[0] != '<' {
return 0
}
curtag, tagfound := p.htmlFindTag(data[1:])
// handle special cases
if !tagfound {
// check for an HTML comment
if size := p.htmlComment(data, doRender); size > 0 {
return size
}
// check for an <hr> tag
if size := p.htmlHr(data, doRender); size > 0 {
return size
}
// no special case recognized
return 0
}
// look for an unindented matching closing tag
// followed by a blank line
found := false
/*
closetag := []byte("\n</" + curtag + ">")
j = len(curtag) + 1
for !found {
// scan for a closing tag at the beginning of a line
if skip := bytes.Index(data[j:], closetag); skip >= 0 {
j += skip + len(closetag)
} else {
break
}
// see if it is the only thing on the line
if skip := p.isEmpty(data[j:]); skip > 0 {
// see if it is followed by a blank line/eof
j += skip
if j >= len(data) {
found = true
i = j
} else {
if skip := p.isEmpty(data[j:]); skip > 0 {
j += skip
found = true
i = j
}
}
}
}
*/
// if not found, try a second pass looking for indented match
// but not if tag is "ins" or "del" (following original Markdown.pl)
if !found && curtag != "ins" && curtag != "del" {
i = 1
for i < len(data) {
i++
for i < len(data) && !(data[i-1] == '<' && data[i] == '/') {
i++
}
if i+2+len(curtag) >= len(data) {
break
}
j = p.htmlFindEnd(curtag, data[i-1:])
if j > 0 {
i += j - 1
found = true
break
}
}
}
if !found {
return 0
}
// the end of the block has been found
if doRender {
// trim newlines
end := i
for end > 0 && data[end-1] == '\n' {
end--
}
finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
}
return i
}
func finalizeHTMLBlock(block *Node) {
block.Literal = block.content
block.content = nil
}
// HTML comment, lax form
func (p *Markdown) htmlComment(data []byte, doRender bool) int {
i := p.inlineHTMLComment(data)
// needs to end with a blank line
if j := p.isEmpty(data[i:]); j > 0 {
size := i + j
if doRender {
// trim trailing newlines
end := size
for end > 0 && data[end-1] == '\n' {
end--
}
block := p.addBlock(HTMLBlock, data[:end])
finalizeHTMLBlock(block)
}
return size
}
return 0
}
// HR, which is the only self-closing block tag considered
func (p *Markdown) htmlHr(data []byte, doRender bool) int {
if len(data) < 4 {
return 0
}
if data[0] != '<' || (data[1] != 'h' && data[1] != 'H') || (data[2] != 'r' && data[2] != 'R') {
return 0
}
if data[3] != ' ' && data[3] != '/' && data[3] != '>' {
// not an <hr> tag after all; at least not a valid one
return 0
}
i := 3
for i < len(data) && data[i] != '>' && data[i] != '\n' {
i++
}
if i < len(data) && data[i] == '>' {
i++
if j := p.isEmpty(data[i:]); j > 0 {
size := i + j
if doRender {
// trim newlines
end := size
for end > 0 && data[end-1] == '\n' {
end--
}
finalizeHTMLBlock(p.addBlock(HTMLBlock, data[:end]))
}
return size
}
}
return 0
}
func (p *Markdown) htmlFindTag(data []byte) (string, bool) {
i := 0
for i < len(data) && isalnum(data[i]) {
i++
}
key := string(data[:i])
if _, ok := blockTags[key]; ok {
return key, true
}
return "", false
}
func (p *Markdown) htmlFindEnd(tag string, data []byte) int {
// assume data[0] == '<' && data[1] == '/' already tested
if tag == "hr" {
return 2
}
// check if tag is a match
closetag := []byte("</" + tag + ">")
if !bytes.HasPrefix(data, closetag) {
return 0
}
i := len(closetag)
// check that the rest of the line is blank
skip := 0
if skip = p.isEmpty(data[i:]); skip == 0 {
return 0
}
i += skip
skip = 0
if i >= len(data) {
return i
}
if p.extensions&LaxHTMLBlocks != 0 {
return i
}
if skip = p.isEmpty(data[i:]); skip == 0 {
// following line must be blank
return 0
}
return i + skip
}
func (*Markdown) isEmpty(data []byte) int {
// it is okay to call isEmpty on an empty buffer
if len(data) == 0 {
return 0
}
var i int
for i = 0; i < len(data) && data[i] != '\n'; i++ {
if data[i] != ' ' && data[i] != '\t' {
return 0
}
}
if i < len(data) && data[i] == '\n' {
i++
}
return i
}
func (*Markdown) isHRule(data []byte) bool {
i := 0
// skip up to three spaces
for i < 3 && data[i] == ' ' {
i++
}
// look at the hrule char
if data[i] != '*' && data[i] != '-' && data[i] != '_' {
return false
}
c := data[i]
// the whole line must be the char or whitespace
n := 0
for i < len(data) && data[i] != '\n' {
switch {
case data[i] == c:
n++
case data[i] != ' ':
return false
}
i++
}
return n >= 3
}
// isFenceLine checks if there's a fence line (e.g., ``` or ``` go) at the beginning of data,
// and returns the end index if so, or 0 otherwise. It also returns the marker found.
// If syntax is not nil, it gets set to the syntax specified in the fence line.
func isFenceLine(data []byte, syntax *string, oldmarker string) (end int, marker string) {
i, size := 0, 0
// skip up to three spaces
for i < len(data) && i < 3 && data[i] == ' ' {
i++
}
// check for the marker characters: ~ or `
if i >= len(data) {
return 0, ""
}
if data[i] != '~' && data[i] != '`' {
return 0, ""
}
c := data[i]
// the whole line must be the same char or whitespace
for i < len(data) && data[i] == c {
size++
i++
}
// the marker char must occur at least 3 times
if size < 3 {
return 0, ""
}
marker = string(data[i-size : i])
// if this is the end marker, it must match the beginning marker
if oldmarker != "" && marker != oldmarker {
return 0, ""
}
// TODO(shurcooL): It's probably a good idea to simplify the 2 code paths here
// into one, always get the syntax, and discard it if the caller doesn't care.
if syntax != nil {
syn := 0
i = skipChar(data, i, ' ')
if i >= len(data) {
if i == len(data) {
return i, marker
}
return 0, ""
}
syntaxStart := i
if data[i] == '{' {
i++
syntaxStart++
for i < len(data) && data[i] != '}' && data[i] != '\n' {
syn++
i++
}
if i >= len(data) || data[i] != '}' {
return 0, ""
}
// strip all whitespace at the beginning and the end
// of the {} block
for syn > 0 && isspace(data[syntaxStart]) {
syntaxStart++
syn--
}
for syn > 0 && isspace(data[syntaxStart+syn-1]) {
syn--
}
i++
} else {
for i < len(data) && !isspace(data[i]) {
syn++
i++
}
}
*syntax = string(data[syntaxStart : syntaxStart+syn])
}
i = skipChar(data, i, ' ')
if i >= len(data) || data[i] != '\n' {
if i == len(data) {
return i, marker
}
return 0, ""
}
return i + 1, marker // Take newline into account.
}
// fencedCodeBlock returns the end index if data contains a fenced code block at the beginning,
// or 0 otherwise. It writes to out if doRender is true, otherwise it has no side effects.
// If doRender is true, a final newline is mandatory to recognize the fenced code block.
func (p *Markdown) fencedCodeBlock(data []byte, doRender bool) int {
var syntax string
beg, marker := isFenceLine(data, &syntax, "")
if beg == 0 || beg >= len(data) {
return 0
}
var work bytes.Buffer
work.Write([]byte(syntax))
work.WriteByte('\n')
for {
// safe to assume beg < len(data)
// check for the end of the code block
fenceEnd, _ := isFenceLine(data[beg:], nil, marker)
if fenceEnd != 0 {
beg += fenceEnd
break
}
// copy the current line
end := skipUntilChar(data, beg, '\n') + 1
// did we reach the end of the buffer without a closing marker?
if end >= len(data) {
return 0
}
// verbatim copy to the working buffer
if doRender {
work.Write(data[beg:end])
}
beg = end
}
if doRender {
block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
block.IsFenced = true
finalizeCodeBlock(block)
}
return beg
}
func unescapeChar(str []byte) []byte {
if str[0] == '\\' {
return []byte{str[1]}
}
return []byte(html.UnescapeString(string(str)))
}
func unescapeString(str []byte) []byte {
if reBackslashOrAmp.Match(str) {
return reEntityOrEscapedChar.ReplaceAllFunc(str, unescapeChar)
}
return str
}
func finalizeCodeBlock(block *Node) {
if block.IsFenced {
newlinePos := bytes.IndexByte(block.content, '\n')
firstLine := block.content[:newlinePos]
rest := block.content[newlinePos+1:]
block.Info = unescapeString(bytes.Trim(firstLine, "\n"))
block.Literal = rest
} else {
block.Literal = block.content
}
block.content = nil
}
func (p *Markdown) table(data []byte) int {
table := p.addBlock(Table, nil)
i, columns := p.tableHeader(data)
if i == 0 {
p.tip = table.Parent
table.Unlink()
return 0
}
p.addBlock(TableBody, nil)
for i < len(data) {
pipes, rowStart := 0, i
for ; i < len(data) && data[i] != '\n'; i++ {
if data[i] == '|' {
pipes++
}
}
if pipes == 0 {
i = rowStart
break
}
// include the newline in data sent to tableRow
if i < len(data) && data[i] == '\n' {
i++
}
p.tableRow(data[rowStart:i], columns, false)
}
return i
}
// check if the specified position is preceded by an odd number of backslashes
func isBackslashEscaped(data []byte, i int) bool {
backslashes := 0
for i-backslashes-1 >= 0 && data[i-backslashes-1] == '\\' {
backslashes++
}
return backslashes&1 == 1
}
func (p *Markdown) tableHeader(data []byte) (size int, columns []CellAlignFlags) {
i := 0
colCount := 1
for i = 0; i < len(data) && data[i] != '\n'; i++ {
if data[i] == '|' && !isBackslashEscaped(data, i) {
colCount++
}
}
// doesn't look like a table header
if colCount == 1 {
return
}
// include the newline in the data sent to tableRow
j := i
if j < len(data) && data[j] == '\n' {
j++
}
header := data[:j]
// column count ignores pipes at beginning or end of line
if data[0] == '|' {
colCount--
}
if i > 2 && data[i-1] == '|' && !isBackslashEscaped(data, i-1) {
colCount--
}
columns = make([]CellAlignFlags, colCount)
// move on to the header underline
i++
if i >= len(data) {
return
}
if data[i] == '|' && !isBackslashEscaped(data, i) {
i++
}
i = skipChar(data, i, ' ')
// each column header is of form: / *:?-+:? *|/ with # dashes + # colons >= 3
// and trailing | optional on last column
col := 0
for i < len(data) && data[i] != '\n' {
dashes := 0
if data[i] == ':' {
i++
columns[col] |= TableAlignmentLeft
dashes++
}
for i < len(data) && data[i] == '-' {
i++
dashes++
}
if i < len(data) && data[i] == ':' {
i++
columns[col] |= TableAlignmentRight
dashes++
}
for i < len(data) && data[i] == ' ' {
i++
}
if i == len(data) {
return
}
// end of column test is messy
switch {
case dashes < 3:
// not a valid column
return
case data[i] == '|' && !isBackslashEscaped(data, i):
// marker found, now skip past trailing whitespace
col++
i++
for i < len(data) && data[i] == ' ' {
i++
}
// trailing junk found after last column
if col >= colCount && i < len(data) && data[i] != '\n' {
return
}
case (data[i] != '|' || isBackslashEscaped(data, i)) && col+1 < colCount:
// something else found where marker was required
return
case data[i] == '\n':
// marker is optional for the last column
col++
default:
// trailing junk found after last column
return
}
}
if col != colCount {
return
}
p.addBlock(TableHead, nil)
p.tableRow(header, columns, true)
size = i
if size < len(data) && data[size] == '\n' {
size++
}
return
}
func (p *Markdown) tableRow(data []byte, columns []CellAlignFlags, header bool) {
p.addBlock(TableRow, nil)
i, col := 0, 0
if data[i] == '|' && !isBackslashEscaped(data, i) {
i++
}
for col = 0; col < len(columns) && i < len(data); col++ {
for i < len(data) && data[i] == ' ' {
i++
}
cellStart := i
for i < len(data) && (data[i] != '|' || isBackslashEscaped(data, i)) && data[i] != '\n' {
i++
}
cellEnd := i
// skip the end-of-cell marker, possibly taking us past end of buffer
i++
for cellEnd > cellStart && cellEnd-1 < len(data) && data[cellEnd-1] == ' ' {
cellEnd--
}
cell := p.addBlock(TableCell, data[cellStart:cellEnd])
cell.IsHeader = header
cell.Align = columns[col]
}
// pad it out with empty columns to get the right number
for ; col < len(columns); col++ {
cell := p.addBlock(TableCell, nil)
cell.IsHeader = header
cell.Align = columns[col]
}
// silently ignore rows with too many cells
}
// returns blockquote prefix length
func (p *Markdown) quotePrefix(data []byte) int {
i := 0
for i < 3 && i < len(data) && data[i] == ' ' {
i++
}
if i < len(data) && data[i] == '>' {
if i+1 < len(data) && data[i+1] == ' ' {
return i + 2
}
return i + 1
}
return 0
}
// blockquote ends with at least one blank line
// followed by something without a blockquote prefix
func (p *Markdown) terminateBlockquote(data []byte, beg, end int) bool {
if p.isEmpty(data[beg:]) <= 0 {
return false
}
if end >= len(data) {
return true
}
return p.quotePrefix(data[end:]) == 0 && p.isEmpty(data[end:]) == 0
}
// parse a blockquote fragment
func (p *Markdown) quote(data []byte) int {
block := p.addBlock(BlockQuote, nil)
var raw bytes.Buffer
beg, end := 0, 0
for beg < len(data) {
end = beg
// Step over whole lines, collecting them. While doing that, check for
// fenced code and if one's found, incorporate it altogether,
// irregardless of any contents inside it
for end < len(data) && data[end] != '\n' {
if p.extensions&FencedCode != 0 {
if i := p.fencedCodeBlock(data[end:], false); i > 0 {
// -1 to compensate for the extra end++ after the loop:
end += i - 1
break
}
}
end++
}
if end < len(data) && data[end] == '\n' {
end++
}
if pre := p.quotePrefix(data[beg:]); pre > 0 {
// skip the prefix
beg += pre
} else if p.terminateBlockquote(data, beg, end) {
break
}
// this line is part of the blockquote
raw.Write(data[beg:end])
beg = end
}
p.block(raw.Bytes())
p.finalize(block)
return end
}
// returns prefix length for block code
func (p *Markdown) codePrefix(data []byte) int {
if len(data) >= 1 && data[0] == '\t' {
return 1
}
if len(data) >= 4 && data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
return 4
}
return 0
}
func (p *Markdown) code(data []byte) int {
var work bytes.Buffer
i := 0
for i < len(data) {
beg := i
for i < len(data) && data[i] != '\n' {
i++
}
if i < len(data) && data[i] == '\n' {
i++
}
blankline := p.isEmpty(data[beg:i]) > 0
if pre := p.codePrefix(data[beg:i]); pre > 0 {
beg += pre
} else if !blankline {
// non-empty, non-prefixed line breaks the pre
i = beg
break
}
// verbatim copy to the working buffer
if blankline {
work.WriteByte('\n')
} else {
work.Write(data[beg:i])
}
}
// trim all the \n off the end of work
workbytes := work.Bytes()
eol := len(workbytes)
for eol > 0 && workbytes[eol-1] == '\n' {
eol--
}
if eol != len(workbytes) {
work.Truncate(eol)
}
work.WriteByte('\n')
block := p.addBlock(CodeBlock, work.Bytes()) // TODO: get rid of temp buffer
block.IsFenced = false
finalizeCodeBlock(block)
return i
}
// returns unordered list item prefix
func (p *Markdown) uliPrefix(data []byte) int {
i := 0
// start with up to 3 spaces
for i < len(data) && i < 3 && data[i] == ' ' {
i++
}
if i >= len(data)-1 {
return 0
}
// need one of {'*', '+', '-'} followed by a space or a tab
if (data[i] != '*' && data[i] != '+' && data[i] != '-') ||
(data[i+1] != ' ' && data[i+1] != '\t') {
return 0
}
return i + 2
}
// returns ordered list item prefix
func (p *Markdown) oliPrefix(data []byte) int {
i := 0
// start with up to 3 spaces
for i < 3 && i < len(data) && data[i] == ' ' {
i++
}
// count the digits
start := i
for i < len(data) && data[i] >= '0' && data[i] <= '9' {
i++
}
if start == i || i >= len(data)-1 {
return 0
}
// we need >= 1 digits followed by a dot and a space or a tab
if data[i] != '.' || !(data[i+1] == ' ' || data[i+1] == '\t') {
return 0
}
return i + 2
}
// returns definition list item prefix
func (p *Markdown) dliPrefix(data []byte) int {
if len(data) < 2 {
return 0
}
i := 0
// need a ':' followed by a space or a tab
if data[i] != ':' || !(data[i+1] == ' ' || data[i+1] == '\t') {
return 0
}
for i < len(data) && data[i] == ' ' {
i++
}
return i + 2
}
// parse ordered or unordered list block
func (p *Markdown) list(data []byte, flags ListType) int {
i := 0
flags |= ListItemBeginningOfList
block := p.addBlock(List, nil)
block.ListFlags = flags
block.Tight = true
for i < len(data) {
skip := p.listItem(data[i:], &flags)
if flags&ListItemContainsBlock != 0 {
block.ListData.Tight = false
}
i += skip
if skip == 0 || flags&ListItemEndOfList != 0 {
break
}
flags &= ^ListItemBeginningOfList
}
above := block.Parent
finalizeList(block)
p.tip = above
return i
}
// Returns true if block ends with a blank line, descending if needed
// into lists and sublists.
func endsWithBlankLine(block *Node) bool {
// TODO: figure this out. Always false now.
for block != nil {
//if block.lastLineBlank {
//return true
//}
t := block.Type
if t == List || t == Item {
block = block.LastChild
} else {
break
}
}
return false
}
func finalizeList(block *Node) {
block.open = false
item := block.FirstChild
for item != nil {
// check for non-final list item ending with blank line:
if endsWithBlankLine(item) && item.Next != nil {
block.ListData.Tight = false
break
}
// recurse into children of list item, to see if there are spaces
// between any of them:
subItem := item.FirstChild
for subItem != nil {
if endsWithBlankLine(subItem) && (item.Next != nil || subItem.Next != nil) {
block.ListData.Tight = false
break
}
subItem = subItem.Next
}
item = item.Next
}
}
// Parse a single list item.
// Assumes initial prefix is already removed if this is a sublist.
func (p *Markdown) listItem(data []byte, flags *ListType) int {
// keep track of the indentation of the first line
itemIndent := 0
if data[0] == '\t' {
itemIndent += 4
} else {
for itemIndent < 3 && data[itemIndent] == ' ' {
itemIndent++
}
}
var bulletChar byte = '*'
i := p.uliPrefix(data)
if i == 0 {
i = p.oliPrefix(data)
} else {
bulletChar = data[i-2]
}
if i == 0 {
i = p.dliPrefix(data)
// reset definition term flag
if i > 0 {
*flags &= ^ListTypeTerm
}
}
if i == 0 {
// if in definition list, set term flag and continue
if *flags&ListTypeDefinition != 0 {
*flags |= ListTypeTerm
} else {
return 0
}
}
// skip leading whitespace on first line
for i < len(data) && data[i] == ' ' {
i++
}
// find the end of the line
line := i
for i > 0 && i < len(data) && data[i-1] != '\n' {
i++
}
// get working buffer
var raw bytes.Buffer
// put the first line into the working buffer
raw.Write(data[line:i])
line = i
// process the following lines
containsBlankLine := false
sublist := 0
gatherlines:
for line < len(data) {
i++
// find the end of this line
for i < len(data) && data[i-1] != '\n' {
i++
}
// if it is an empty line, guess that it is part of this item
// and move on to the next line
if p.isEmpty(data[line:i]) > 0 {
containsBlankLine = true
line = i
continue
}
// calculate the indentation
indent := 0
indentIndex := 0
if data[line] == '\t' {
indentIndex++
indent += 4
} else {
for indent < 4 && line+indent < i && data[line+indent] == ' ' {
indent++
indentIndex++
}
}
chunk := data[line+indentIndex : i]
// evaluate how this line fits in
switch {
// is this a nested list item?
case (p.uliPrefix(chunk) > 0 && !p.isHRule(chunk)) ||
p.oliPrefix(chunk) > 0 ||
p.dliPrefix(chunk) > 0:
if containsBlankLine {
*flags |= ListItemContainsBlock
}
// to be a nested list, it must be indented more
// if not, it is the next item in the same list
if indent <= itemIndent {
break gatherlines
}
// is this the first item in the nested list?
if sublist == 0 {
sublist = raw.Len()
}
// is this a nested prefix heading?
case p.isPrefixHeading(chunk):
// if the heading is not indented, it is not nested in the list
// and thus ends the list
if containsBlankLine && indent < 4 {
*flags |= ListItemEndOfList
break gatherlines
}
*flags |= ListItemContainsBlock
// anything following an empty line is only part
// of this item if it is indented 4 spaces
// (regardless of the indentation of the beginning of the item)
case containsBlankLine && indent < 4:
if *flags&ListTypeDefinition != 0 && i < len(data)-1 {
// is the next item still a part of this list?
next := i
for next < len(data) && data[next] != '\n' {
next++
}
for next < len(data)-1 && data[next] == '\n' {
next++
}
if i < len(data)-1 && data[i] != ':' && data[next] != ':' {
*flags |= ListItemEndOfList
}
} else {
*flags |= ListItemEndOfList
}
break gatherlines
// a blank line means this should be parsed as a block
case containsBlankLine:
raw.WriteByte('\n')
*flags |= ListItemContainsBlock
}
// if this line was preceded by one or more blanks,
// re-introduce the blank into the buffer
if containsBlankLine {
containsBlankLine = false
raw.WriteByte('\n')
}
// add the line into the working buffer without prefix
raw.Write(data[line+indentIndex : i])
line = i
}
rawBytes := raw.Bytes()
block := p.addBlock(Item, nil)
block.ListFlags = *flags
block.Tight = false
block.BulletChar = bulletChar
block.Delimiter = '.' // Only '.' is possible in Markdown, but ')' will also be possible in CommonMark
// render the contents of the list item
if *flags&ListItemContainsBlock != 0 && *flags&ListTypeTerm == 0 {
// intermediate render of block item, except for definition term
if sublist > 0 {
p.block(rawBytes[:sublist])
p.block(rawBytes[sublist:])
} else {
p.block(rawBytes)
}
} else {
// intermediate render of inline item
if sublist > 0 {
child := p.addChild(Paragraph, 0)
child.content = rawBytes[:sublist]
p.block(rawBytes[sublist:])
} else {
child := p.addChild(Paragraph, 0)
child.content = rawBytes
}
}
return line
}
// render a single paragraph that has already been parsed out
func (p *Markdown) renderParagraph(data []byte) {
if len(data) == 0 {
return
}
// trim leading spaces
beg := 0
for data[beg] == ' ' {
beg++
}
end := len(data)
// trim trailing newline
if data[len(data)-1] == '\n' {
end--
}
// trim trailing spaces
for end > beg && data[end-1] == ' ' {
end--
}
p.addBlock(Paragraph, data[beg:end])
}
func (p *Markdown) paragraph(data []byte) int {
// prev: index of 1st char of previous line
// line: index of 1st char of current line
// i: index of cursor/end of current line
var prev, line, i int
tabSize := TabSizeDefault
if p.extensions&TabSizeEight != 0 {
tabSize = TabSizeDouble
}
// keep going until we find something to mark the end of the paragraph
for i < len(data) {
// mark the beginning of the current line
prev = line
current := data[i:]
line = i
// did we find a reference or a footnote? If so, end a paragraph
// preceding it and report that we have consumed up to the end of that
// reference:
if refEnd := isReference(p, current, tabSize); refEnd > 0 {
p.renderParagraph(data[:i])
return i + refEnd
}
// did we find a blank line marking the end of the paragraph?
if n := p.isEmpty(current); n > 0 {
// did this blank line followed by a definition list item?
if p.extensions&DefinitionLists != 0 {
if i < len(data)-1 && data[i+1] == ':' {
return p.list(data[prev:], ListTypeDefinition)
}
}
p.renderParagraph(data[:i])
return i + n
}
// an underline under some text marks a heading, so our paragraph ended on prev line
if i > 0 {
if level := p.isUnderlinedHeading(current); level > 0 {
// render the paragraph
p.renderParagraph(data[:prev])
// ignore leading and trailing whitespace
eol := i - 1
for prev < eol && data[prev] == ' ' {
prev++
}
for eol > prev && data[eol-1] == ' ' {
eol--
}
id := ""
if p.extensions&AutoHeadingIDs != 0 {
id = sanitized_anchor_name.Create(string(data[prev:eol]))
}
block := p.addBlock(Heading, data[prev:eol])
block.Level = level
block.HeadingID = id
// find the end of the underline
for i < len(data) && data[i] != '\n' {
i++
}
return i
}
}
// if the next line starts a block of HTML, then the paragraph ends here
if p.extensions&LaxHTMLBlocks != 0 {
if data[i] == '<' && p.html(current, false) > 0 {
// rewind to before the HTML block
p.renderParagraph(data[:i])
return i
}
}
// if there's a prefixed heading or a horizontal rule after this, paragraph is over
if p.isPrefixHeading(current) || p.isHRule(current) {
p.renderParagraph(data[:i])
return i
}
// if there's a fenced code block, paragraph is over
if p.extensions&FencedCode != 0 {
if p.fencedCodeBlock(current, false) > 0 {
p.renderParagraph(data[:i])
return i
}
}
// if there's a definition list item, prev line is a definition term
if p.extensions&DefinitionLists != 0 {
if p.dliPrefix(current) != 0 {
ret := p.list(data[prev:], ListTypeDefinition)
return ret
}
}
// if there's a list after this, paragraph is over
if p.extensions&NoEmptyLineBeforeBlock != 0 {
if p.uliPrefix(current) != 0 ||
p.oliPrefix(current) != 0 ||
p.quotePrefix(current) != 0 ||
p.codePrefix(current) != 0 {
p.renderParagraph(data[:i])
return i
}
}
// otherwise, scan to the beginning of the next line
nl := bytes.IndexByte(data[i:], '\n')
if nl >= 0 {
i += nl + 1
} else {
i += len(data[i:])
}
}
p.renderParagraph(data[:i])
return i
}
func skipChar(data []byte, start int, char byte) int {
i := start
for i < len(data) && data[i] == char {
i++
}
return i
}
func skipUntilChar(text []byte, start int, char byte) int {
i := start
for i < len(text) && text[i] != char {
i++
}
return i
}