// // 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 codeBlockMarker := "" 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] if p.flags&EXTENSION_FENCED_CODE != 0 { // determine if in or out of codeblock // if in codeblock, ignore normal list processing _, marker := isFenceLine(chunk, nil, codeBlockMarker, false) if marker != "" { if codeBlockMarker == "" { // start of codeblock codeBlockMarker = marker } else { // end of codeblock. *flags |= LIST_ITEM_CONTAINS_BLOCK codeBlockMarker = "" } } // we are in a codeblock, write line, and continue if codeBlockMarker != "" || marker != "" { raw.Write(data[line+indent : i]) line = i continue gatherlines } } // 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) }