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//
// 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"
"unicode"
)
// Parse block-level data.
// Note: this function and many that it calls assume that
// the input buffer ends with a newline.
func (p *parser) block(out *bytes.Buffer, data []byte) {
if len(data) == 0 || data[len(data)-1] != '\n' {
panic("block input is missing terminating newline")
}
// 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 header:
//
// # Header 1
// ## Header 2
// ...
// ###### Header 6
if p.isPrefixHeader(data) {
data = data[p.prefixHeader(out, data):]
continue
}
// block of preformatted HTML:
//
// <div>
// ...
// </div>
if data[0] == '<' {
if i := p.html(out, data, true); i > 0 {
data = data[i:]
continue
}
}
// title block
//
// % stuff
// % more stuff
// % even more stuff
if p.flags&EXTENSION_TITLEBLOCK != 0 {
if data[0] == '%' {
if i := p.titleBlock(out, 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(out, data):]
continue
}
// fenced code block:
//
// ``` go
// func fact(n int) int {
// if n <= 1 {
// return n
// }
// return n * fact(n-1)
// }
// ```
if p.flags&EXTENSION_FENCED_CODE != 0 {
if i := p.fencedCodeBlock(out, data, true); i > 0 {
data = data[i:]
continue
}
}
// horizontal rule:
//
// ------
// or
// ******
// or
// ______
if p.isHRule(data) {
p.r.HRule(out)
var i int
for i = 0; 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(out, data):]
continue
}
// table:
//
// Name | Age | Phone
// ------|-----|---------
// Bob | 31 | 555-1234
// Alice | 27 | 555-4321
if p.flags&EXTENSION_TABLES != 0 {
if i := p.table(out, 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(out, data, 0):]
continue
}
// a numbered/ordered list:
//
// 1. Item 1
// 2. Item 2
if p.oliPrefix(data) > 0 {
data = data[p.list(out, data, LIST_TYPE_ORDERED):]
continue
}
// definition lists:
//
// Term 1
// : Definition a
// : Definition b
//
// Term 2
// : Definition c
if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
if p.dliPrefix(data) > 0 {
data = data[p.list(out, data, LIST_TYPE_DEFINITION):]
continue
}
}
// anything else must look like a normal paragraph
// note: this finds underlined headers, too
data = data[p.paragraph(out, data):]
}
p.nesting--
}
func (p *parser) isPrefixHeader(data []byte) bool {
if data[0] != '#' {
return false
}
if p.flags&EXTENSION_SPACE_HEADERS != 0 {
level := 0
for level < 6 && data[level] == '#' {
level++
}
if data[level] != ' ' {
return false
}
}
return true
}
func (p *parser) prefixHeader(out *bytes.Buffer, data []byte) int {
level := 0
for level < 6 && data[level] == '#' {
level++
}
i := skipChar(data, level, ' ')
end := skipUntilChar(data, i, '\n')
skip := end
id := ""
if p.flags&EXTENSION_HEADER_IDS != 0 {
j, k := 0, 0
// find start/end of header id
for j = i; j < end-1 && (data[j] != '{' || data[j+1] != '#'); j++ {
}
for k = j + 1; k < end && data[k] != '}'; k++ {
}
// extract header 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.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
id = SanitizedAnchorName(string(data[i:end]))
}
work := func() bool {
p.inline(out, data[i:end])
return true
}
p.r.Header(out, work, level, id)
}
return skip
}
func (p *parser) isUnderlinedHeader(data []byte) int {
// test of level 1 header
if data[0] == '=' {
i := skipChar(data, 1, '=')
i = skipChar(data, i, ' ')
if data[i] == '\n' {
return 1
} else {
return 0
}
}
// test of level 2 header
if data[0] == '-' {
i := skipChar(data, 1, '-')
i = skipChar(data, i, ' ')
if data[i] == '\n' {
return 2
} else {
return 0
}
}
return 0
}
func (p *parser) titleBlock(out *bytes.Buffer, 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"))
p.r.TitleBlock(out, data)
return len(data)
}
func (p *parser) html(out *bytes.Buffer, 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(out, data, doRender); size > 0 {
return size
}
// check for an <hr> tag
if size := p.htmlHr(out, data, doRender); size > 0 {
return size
}
// check for HTML CDATA
if size := p.htmlCDATA(out, 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--
}
p.r.BlockHtml(out, data[:end])
}
return i
}
func (p *parser) renderHTMLBlock(out *bytes.Buffer, data []byte, start int, doRender bool) int {
// html block needs to end with a blank line
if i := p.isEmpty(data[start:]); i > 0 {
size := start + i
if doRender {
// trim trailing newlines
end := size
for end > 0 && data[end-1] == '\n' {
end--
}
p.r.BlockHtml(out, data[:end])
}
return size
}
return 0
}
// HTML comment, lax form
func (p *parser) htmlComment(out *bytes.Buffer, data []byte, doRender bool) int {
i := p.inlineHTMLComment(out, data)
return p.renderHTMLBlock(out, data, i, doRender)
}
// HTML CDATA section
func (p *parser) htmlCDATA(out *bytes.Buffer, data []byte, doRender bool) int {
const cdataTag = "<![cdata["
const cdataTagLen = len(cdataTag)
if len(data) < cdataTagLen+1 {
return 0
}
if !bytes.Equal(bytes.ToLower(data[:cdataTagLen]), []byte(cdataTag)) {
return 0
}
i := cdataTagLen
// scan for an end-of-comment marker, across lines if necessary
for i < len(data) && !(data[i-2] == ']' && data[i-1] == ']' && data[i] == '>') {
i++
}
i++
// no end-of-comment marker
if i >= len(data) {
return 0
}
return p.renderHTMLBlock(out, data, i, doRender)
}
// HR, which is the only self-closing block tag considered
func (p *parser) htmlHr(out *bytes.Buffer, data []byte, doRender bool) int {
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 data[i] != '>' && data[i] != '\n' {
i++
}
if data[i] == '>' {
return p.renderHTMLBlock(out, data, i+1, doRender)
}
return 0
}
func (p *parser) htmlFindTag(data []byte) (string, bool) {
i := 0
for isalnum(data[i]) {
i++
}
key := string(data[:i])
if _, ok := blockTags[key]; ok {
return key, true
}
return "", false
}
func (p *parser) htmlFindEnd(tag string, data []byte) int {
// assume data[0] == '<' && data[1] == '/' already tested
// 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.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
return i
}
if skip = p.isEmpty(data[i:]); skip == 0 {
// following line must be blank
return 0
}
return i + skip
}
func (*parser) 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
}
}
return i + 1
}
func (*parser) 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 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.
// A final newline is mandatory to recognize the fence line, unless newlineOptional is true.
func isFenceLine(data []byte, syntax *string, oldmarker string, newlineOptional bool) (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 newlineOptional && 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 newlineOptional && 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 *parser) fencedCodeBlock(out *bytes.Buffer, data []byte, doRender bool) int {
var syntax string
beg, marker := isFenceLine(data, &syntax, "", false)
if beg == 0 || beg >= len(data) {
return 0
}
var work bytes.Buffer
for {
// safe to assume beg < len(data)
// check for the end of the code block
newlineOptional := !doRender
fenceEnd, _ := isFenceLine(data[beg:], nil, marker, newlineOptional)
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 {
p.r.BlockCode(out, work.Bytes(), syntax)
}
return beg
}
func (p *parser) table(out *bytes.Buffer, data []byte) int {
var header bytes.Buffer
i, columns := p.tableHeader(&header, data)
if i == 0 {
return 0
}
var body bytes.Buffer
for i < len(data) {
pipes, rowStart := 0, i
for ; data[i] != '\n'; i++ {
if data[i] == '|' {
pipes++
}
}
if pipes == 0 {
i = rowStart
break
}
// include the newline in data sent to tableRow
i++
p.tableRow(&body, data[rowStart:i], columns, false)
}
p.r.Table(out, header.Bytes(), body.Bytes(), columns)
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 *parser) tableHeader(out *bytes.Buffer, data []byte) (size int, columns []int) {
i := 0
colCount := 1
for i = 0; 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
header := data[:i+1]
// 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([]int, 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 data[i] != '\n' {
dashes := 0
if data[i] == ':' {
i++
columns[col] |= TABLE_ALIGNMENT_LEFT
dashes++
}
for data[i] == '-' {
i++
dashes++
}
if data[i] == ':' {
i++
columns[col] |= TABLE_ALIGNMENT_RIGHT
dashes++
}
for data[i] == ' ' {
i++
}
// 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 data[i] == ' ' {
i++
}
// trailing junk found after last column
if col >= colCount && 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.tableRow(out, header, columns, true)
size = i + 1
return
}
func (p *parser) tableRow(out *bytes.Buffer, data []byte, columns []int, header bool) {
i, col := 0, 0
var rowWork bytes.Buffer
if data[i] == '|' && !isBackslashEscaped(data, i) {
i++
}
for col = 0; col < len(columns) && i < len(data); col++ {
for data[i] == ' ' {
i++
}
cellStart := i
for (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 && data[cellEnd-1] == ' ' {
cellEnd--
}
var cellWork bytes.Buffer
p.inline(&cellWork, data[cellStart:cellEnd])
if header {
p.r.TableHeaderCell(&rowWork, cellWork.Bytes(), columns[col])
} else {
p.r.TableCell(&rowWork, cellWork.Bytes(), columns[col])
}
}
// pad it out with empty columns to get the right number
for ; col < len(columns); col++ {
if header {
p.r.TableHeaderCell(&rowWork, nil, columns[col])
} else {
p.r.TableCell(&rowWork, nil, columns[col])
}
}
// silently ignore rows with too many cells
p.r.TableRow(out, rowWork.Bytes())
}
// returns blockquote prefix length
func (p *parser) quotePrefix(data []byte) int {
i := 0
for i < 3 && data[i] == ' ' {
i++
}
if data[i] == '>' {
if 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 *parser) 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 *parser) quote(out *bytes.Buffer, data []byte) int {
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 data[end] != '\n' {
if p.flags&EXTENSION_FENCED_CODE != 0 {
if i := p.fencedCodeBlock(out, data[end:], false); i > 0 {
// -1 to compensate for the extra end++ after the loop:
end += i - 1
break
}
}
end++
}
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
}
var cooked bytes.Buffer
p.block(&cooked, raw.Bytes())
p.r.BlockQuote(out, cooked.Bytes())
return end
}
// returns prefix length for block code
func (p *parser) codePrefix(data []byte) int {
if data[0] == ' ' && data[1] == ' ' && data[2] == ' ' && data[3] == ' ' {
return 4
}
return 0
}
func (p *parser) code(out *bytes.Buffer, data []byte) int {
var work bytes.Buffer
i := 0
for i < len(data) {
beg := i
for data[i] != '\n' {
i++
}
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 buffeu
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')
p.r.BlockCode(out, work.Bytes(), "")
return i
}
// returns unordered list item prefix
func (p *parser) uliPrefix(data []byte) int {
i := 0
// start with up to 3 spaces
for i < 3 && data[i] == ' ' {
i++
}
// need a *, +, or - followed by a space
if (data[i] != '*' && data[i] != '+' && data[i] != '-') ||
data[i+1] != ' ' {
return 0
}
return i + 2
}
// returns ordered list item prefix
func (p *parser) oliPrefix(data []byte) int {
i := 0
// start with up to 3 spaces
for i < 3 && data[i] == ' ' {
i++
}
// count the digits
start := i
for data[i] >= '0' && data[i] <= '9' {
i++
}
// we need >= 1 digits followed by a dot and a space
if start == i || data[i] != '.' || data[i+1] != ' ' {
return 0
}
return i + 2
}
// returns definition list item prefix
func (p *parser) dliPrefix(data []byte) int {
i := 0
// need a : followed by a spaces
if data[i] != ':' || data[i+1] != ' ' {
return 0
}
for data[i] == ' ' {
i++
}
return i + 2
}
// parse ordered or unordered list block
func (p *parser) list(out *bytes.Buffer, data []byte, flags int) int {
i := 0
flags |= LIST_ITEM_BEGINNING_OF_LIST
work := func() bool {
for i < len(data) {
skip := p.listItem(out, data[i:], &flags)
i += skip
if skip == 0 || flags&LIST_ITEM_END_OF_LIST != 0 {
break
}
flags &= ^LIST_ITEM_BEGINNING_OF_LIST
}
return true
}
p.r.List(out, work, flags)
return i
}
// Parse a single list item.
// Assumes initial prefix is already removed if this is a sublist.
func (p *parser) listItem(out *bytes.Buffer, data []byte, flags *int) int {
// keep track of the indentation of the first line
itemIndent := 0
for itemIndent < 3 && data[itemIndent] == ' ' {
itemIndent++
}
i := p.uliPrefix(data)
if i == 0 {
i = p.oliPrefix(data)
}
if i == 0 {
i = p.dliPrefix(data)
// reset definition term flag
if i > 0 {
*flags &= ^LIST_TYPE_TERM
}
}
if i == 0 {
// if in defnition list, set term flag and continue
if *flags&LIST_TYPE_DEFINITION != 0 {
*flags |= LIST_TYPE_TERM
} else {
return 0
}
}
// skip leading whitespace on first line
for data[i] == ' ' {
i++
}
// find the end of the line
line := i
for i > 0 && 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 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
raw.Write(data[line:i])
line = i
continue
}
// calculate the indentation
indent := 0
for indent < 4 && line+indent < i && data[line+indent] == ' ' {
indent++
}
chunk := data[line+indent : 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 {
// end the list if the type changed after a blank line
if indent <= itemIndent &&
((*flags&LIST_TYPE_ORDERED != 0 && p.uliPrefix(chunk) > 0) ||
(*flags&LIST_TYPE_ORDERED == 0 && p.oliPrefix(chunk) > 0)) {
*flags |= LIST_ITEM_END_OF_LIST
break gatherlines
}
*flags |= LIST_ITEM_CONTAINS_BLOCK
}
// 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 header?
case p.isPrefixHeader(chunk):
// if the header is not indented, it is not nested in the list
// and thus ends the list
if containsBlankLine && indent < 4 {
*flags |= LIST_ITEM_END_OF_LIST
break gatherlines
}
*flags |= LIST_ITEM_CONTAINS_BLOCK
// 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&LIST_TYPE_DEFINITION != 0 && i < len(data)-1 {
// is the next item still a part of this list?
next := i
for data[next] != '\n' {
next++
}
for next < len(data)-1 && data[next] == '\n' {
next++
}
if i < len(data)-1 && data[i] != ':' && data[next] != ':' {
*flags |= LIST_ITEM_END_OF_LIST
}
} else {
*flags |= LIST_ITEM_END_OF_LIST
}
break gatherlines
// a blank line means this should be parsed as a block
case containsBlankLine:
*flags |= LIST_ITEM_CONTAINS_BLOCK
}
containsBlankLine = false
// add the line into the working buffer without prefix
raw.Write(data[line+indent : i])
line = i
}
// If reached end of data, the Renderer.ListItem call we're going to make below
// is definitely the last in the list.
if line >= len(data) {
*flags |= LIST_ITEM_END_OF_LIST
}
rawBytes := raw.Bytes()
// render the contents of the list item
var cooked bytes.Buffer
if *flags&LIST_ITEM_CONTAINS_BLOCK != 0 && *flags&LIST_TYPE_TERM == 0 {
// intermediate render of block item, except for definition term
if sublist > 0 {
p.block(&cooked, rawBytes[:sublist])
p.block(&cooked, rawBytes[sublist:])
} else {
p.block(&cooked, rawBytes)
}
} else {
// intermediate render of inline item
if sublist > 0 {
p.inline(&cooked, rawBytes[:sublist])
p.block(&cooked, rawBytes[sublist:])
} else {
p.inline(&cooked, rawBytes)
}
}
// render the actual list item
cookedBytes := cooked.Bytes()
parsedEnd := len(cookedBytes)
// strip trailing newlines
for parsedEnd > 0 && cookedBytes[parsedEnd-1] == '\n' {
parsedEnd--
}
p.r.ListItem(out, cookedBytes[:parsedEnd], *flags)
return line
}
// render a single paragraph that has already been parsed out
func (p *parser) renderParagraph(out *bytes.Buffer, data []byte) {
if len(data) == 0 {
return
}
// trim leading spaces
beg := 0
for data[beg] == ' ' {
beg++
}
// trim trailing newline
end := len(data) - 1
// trim trailing spaces
for end > beg && data[end-1] == ' ' {
end--
}
work := func() bool {
p.inline(out, data[beg:end])
return true
}
p.r.Paragraph(out, work)
}
func (p *parser) paragraph(out *bytes.Buffer, 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
// 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 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.flags&EXTENSION_DEFINITION_LISTS != 0 {
if i < len(data)-1 && data[i+1] == ':' {
return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
}
}
p.renderParagraph(out, data[:i])
return i + n
}
// an underline under some text marks a header, so our paragraph ended on prev line
if i > 0 {
if level := p.isUnderlinedHeader(current); level > 0 {
// render the paragraph
p.renderParagraph(out, data[:prev])
// ignore leading and trailing whitespace
eol := i - 1
for prev < eol && data[prev] == ' ' {
prev++
}
for eol > prev && data[eol-1] == ' ' {
eol--
}
// render the header
// this ugly double closure avoids forcing variables onto the heap
work := func(o *bytes.Buffer, pp *parser, d []byte) func() bool {
return func() bool {
pp.inline(o, d)
return true
}
}(out, p, data[prev:eol])
id := ""
if p.flags&EXTENSION_AUTO_HEADER_IDS != 0 {
id = SanitizedAnchorName(string(data[prev:eol]))
}
p.r.Header(out, work, level, id)
// find the end of the underline
for data[i] != '\n' {
i++
}
return i
}
}
// if the next line starts a block of HTML, then the paragraph ends here
if p.flags&EXTENSION_LAX_HTML_BLOCKS != 0 {
if data[i] == '<' && p.html(out, current, false) > 0 {
// rewind to before the HTML block
p.renderParagraph(out, data[:i])
return i
}
}
// if there's a prefixed header or a horizontal rule after this, paragraph is over
if p.isPrefixHeader(current) || p.isHRule(current) {
p.renderParagraph(out, data[:i])
return i
}
// if there's a fenced code block, paragraph is over
if p.flags&EXTENSION_FENCED_CODE != 0 {
if p.fencedCodeBlock(out, current, false) > 0 {
p.renderParagraph(out, data[:i])
return i
}
}
// if there's a definition list item, prev line is a definition term
if p.flags&EXTENSION_DEFINITION_LISTS != 0 {
if p.dliPrefix(current) != 0 {
return p.list(out, data[prev:], LIST_TYPE_DEFINITION)
}
}
// if there's a list after this, paragraph is over
if p.flags&EXTENSION_NO_EMPTY_LINE_BEFORE_BLOCK != 0 {
if p.uliPrefix(current) != 0 ||
p.oliPrefix(current) != 0 ||
p.quotePrefix(current) != 0 ||
p.codePrefix(current) != 0 {
p.renderParagraph(out, data[:i])
return i
}
}
// otherwise, scan to the beginning of the next line
for data[i] != '\n' {
i++
}
i++
}
p.renderParagraph(out, data[:i])
return i
}
// SanitizedAnchorName returns a sanitized anchor name for the given text.
//
// It implements the algorithm specified in the package comment.
func SanitizedAnchorName(text string) string {
var anchorName []rune
futureDash := false
for _, r := range text {
switch {
case unicode.IsLetter(r) || unicode.IsNumber(r):
if futureDash && len(anchorName) > 0 {
anchorName = append(anchorName, '-')
}
futureDash = false
anchorName = append(anchorName, unicode.ToLower(r))
default:
futureDash = true
}
}
return string(anchorName)
}