1
0
mirror of https://github.com/danog/blackfriday.git synced 2024-12-02 09:27:49 +01:00
blackfriday/block.go
Nathan Glenn 11635eb403 Accept info strings in code fences (#448)
* Accept info strings in code fences

According to the common mark standard, code fence info strings can be anything,
not just single words. Update the tests and parser accordingly.

The formatter already expected an info string with a language and HTML classes,
so this does not need to change. Update the LaTeX formatter to take the first
word of the info string as the language.

Fixes #410 (in v1).

* Don't output whole info string as code classes

This follows the common mark specification.

* run go fmt
2018-04-28 13:25:19 +03:00

1452 lines
30 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"
"strings"
"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 info string here
// 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, info *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 info string, and discard it if the caller doesn't care.
if info != nil {
infoLength := 0
i = skipChar(data, i, ' ')
if i >= len(data) {
if newlineOptional && i == len(data) {
return i, marker
}
return 0, ""
}
infoStart := i
if data[i] == '{' {
i++
infoStart++
for i < len(data) && data[i] != '}' && data[i] != '\n' {
infoLength++
i++
}
if i >= len(data) || data[i] != '}' {
return 0, ""
}
// strip all whitespace at the beginning and the end
// of the {} block
for infoLength > 0 && isspace(data[infoStart]) {
infoStart++
infoLength--
}
for infoLength > 0 && isspace(data[infoStart+infoLength-1]) {
infoLength--
}
i++
} else {
for i < len(data) && !isverticalspace(data[i]) {
infoLength++
i++
}
}
*info = strings.TrimSpace(string(data[infoStart : infoStart+infoLength]))
}
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 infoString string
beg, marker := isFenceLine(data, &infoString, "", 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(), infoString)
}
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)
}