| // |
| // 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" |
| |
| "github.com/shurcooL/sanitized_anchor_name" |
| ) |
| |
| // 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.fencedCode(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 = sanitized_anchor_name.Create(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 |
| } |
| |
| // 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 |
| } |
| |
| // HTML comment, lax form |
| func (p *parser) htmlComment(out *bytes.Buffer, data []byte, doRender bool) int { |
| i := p.inlineHtmlComment(out, 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-- |
| } |
| p.r.BlockHtml(out, data[:end]) |
| } |
| return size |
| } |
| return 0 |
| } |
| |
| // 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] == '>' { |
| 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-- |
| } |
| p.r.BlockHtml(out, data[:end]) |
| } |
| return size |
| } |
| } |
| |
| 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 (p *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 (p *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 |
| } |
| |
| func (p *parser) isFencedCode(data []byte, syntax **string, oldmarker string) (skip int, marker string) { |
| i, size := 0, 0 |
| skip = 0 |
| |
| // skip up to three spaces |
| for i < len(data) && i < 3 && data[i] == ' ' { |
| i++ |
| } |
| if i >= len(data) { |
| return |
| } |
| |
| // check for the marker characters: ~ or ` |
| if data[i] != '~' && data[i] != '`' { |
| return |
| } |
| |
| c := data[i] |
| |
| // the whole line must be the same char or whitespace |
| for i < len(data) && data[i] == c { |
| size++ |
| i++ |
| } |
| |
| if i >= len(data) { |
| return |
| } |
| |
| // the marker char must occur at least 3 times |
| if size < 3 { |
| return |
| } |
| marker = string(data[i-size : i]) |
| |
| // if this is the end marker, it must match the beginning marker |
| if oldmarker != "" && marker != oldmarker { |
| return |
| } |
| |
| if syntax != nil { |
| syn := 0 |
| i = skipChar(data, i, ' ') |
| |
| if i >= len(data) { |
| return |
| } |
| |
| 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 |
| } |
| |
| // 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++ |
| } |
| } |
| |
| language := string(data[syntaxStart : syntaxStart+syn]) |
| *syntax = &language |
| } |
| |
| i = skipChar(data, i, ' ') |
| if i >= len(data) || data[i] != '\n' { |
| return |
| } |
| |
| skip = i + 1 |
| return |
| } |
| |
| func (p *parser) fencedCode(out *bytes.Buffer, data []byte, doRender bool) int { |
| var lang *string |
| beg, marker := p.isFencedCode(data, &lang, "") |
| 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 |
| fenceEnd, _ := p.isFencedCode(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 |
| } |
| |
| syntax := "" |
| if lang != nil { |
| syntax = *lang |
| } |
| |
| 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.fencedCode(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 |
| 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 { |
| *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: |
| raw.WriteByte('\n') |
| *flags |= LIST_ITEM_CONTAINS_BLOCK |
| } |
| |
| // if this line was preceeded 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+indent : i]) |
| |
| line = i |
| } |
| |
| 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 = sanitized_anchor_name.Create(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.fencedCode(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 |
| } |