diff options
Diffstat (limited to 'vendor/gopkg.in/russross/blackfriday.v2/markdown.go')
| -rw-r--r-- | vendor/gopkg.in/russross/blackfriday.v2/markdown.go | 940 |
1 files changed, 940 insertions, 0 deletions
diff --git a/vendor/gopkg.in/russross/blackfriday.v2/markdown.go b/vendor/gopkg.in/russross/blackfriday.v2/markdown.go new file mode 100644 index 0000000..ff61cb0 --- /dev/null +++ b/vendor/gopkg.in/russross/blackfriday.v2/markdown.go @@ -0,0 +1,940 @@ +// 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. + +package blackfriday + +import ( + "bytes" + "fmt" + "io" + "strings" + "unicode/utf8" +) + +// +// Markdown parsing and processing +// + +// Version string of the package. Appears in the rendered document when +// CompletePage flag is on. +const Version = "2.0" + +// Extensions is a bitwise or'ed collection of enabled Blackfriday's +// extensions. +type Extensions int + +// These are the supported markdown parsing extensions. +// OR these values together to select multiple extensions. +const ( + NoExtensions Extensions = 0 + NoIntraEmphasis Extensions = 1 << iota // Ignore emphasis markers inside words + Tables // Render tables + FencedCode // Render fenced code blocks + Autolink // Detect embedded URLs that are not explicitly marked + Strikethrough // Strikethrough text using ~~test~~ + LaxHTMLBlocks // Loosen up HTML block parsing rules + SpaceHeadings // Be strict about prefix heading rules + HardLineBreak // Translate newlines into line breaks + TabSizeEight // Expand tabs to eight spaces instead of four + Footnotes // Pandoc-style footnotes + NoEmptyLineBeforeBlock // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block + HeadingIDs // specify heading IDs with {#id} + Titleblock // Titleblock ala pandoc + AutoHeadingIDs // Create the heading ID from the text + BackslashLineBreak // Translate trailing backslashes into line breaks + DefinitionLists // Render definition lists + + CommonHTMLFlags HTMLFlags = UseXHTML | Smartypants | + SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes + + CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode | + Autolink | Strikethrough | SpaceHeadings | HeadingIDs | + BackslashLineBreak | DefinitionLists +) + +// ListType contains bitwise or'ed flags for list and list item objects. +type ListType int + +// These are the possible flag values for the ListItem renderer. +// Multiple flag values may be ORed together. +// These are mostly of interest if you are writing a new output format. +const ( + ListTypeOrdered ListType = 1 << iota + ListTypeDefinition + ListTypeTerm + + ListItemContainsBlock + ListItemBeginningOfList // TODO: figure out if this is of any use now + ListItemEndOfList +) + +// CellAlignFlags holds a type of alignment in a table cell. +type CellAlignFlags int + +// These are the possible flag values for the table cell renderer. +// Only a single one of these values will be used; they are not ORed together. +// These are mostly of interest if you are writing a new output format. +const ( + TableAlignmentLeft CellAlignFlags = 1 << iota + TableAlignmentRight + TableAlignmentCenter = (TableAlignmentLeft | TableAlignmentRight) +) + +// The size of a tab stop. +const ( + TabSizeDefault = 4 + TabSizeDouble = 8 +) + +// blockTags is a set of tags that are recognized as HTML block tags. +// Any of these can be included in markdown text without special escaping. +var blockTags = map[string]struct{}{ + "blockquote": struct{}{}, + "del": struct{}{}, + "div": struct{}{}, + "dl": struct{}{}, + "fieldset": struct{}{}, + "form": struct{}{}, + "h1": struct{}{}, + "h2": struct{}{}, + "h3": struct{}{}, + "h4": struct{}{}, + "h5": struct{}{}, + "h6": struct{}{}, + "iframe": struct{}{}, + "ins": struct{}{}, + "math": struct{}{}, + "noscript": struct{}{}, + "ol": struct{}{}, + "pre": struct{}{}, + "p": struct{}{}, + "script": struct{}{}, + "style": struct{}{}, + "table": struct{}{}, + "ul": struct{}{}, + + // HTML5 + "address": struct{}{}, + "article": struct{}{}, + "aside": struct{}{}, + "canvas": struct{}{}, + "figcaption": struct{}{}, + "figure": struct{}{}, + "footer": struct{}{}, + "header": struct{}{}, + "hgroup": struct{}{}, + "main": struct{}{}, + "nav": struct{}{}, + "output": struct{}{}, + "progress": struct{}{}, + "section": struct{}{}, + "video": struct{}{}, +} + +// Renderer is the rendering interface. This is mostly of interest if you are +// implementing a new rendering format. +// +// Only an HTML implementation is provided in this repository, see the README +// for external implementations. +type Renderer interface { + // RenderNode is the main rendering method. It will be called once for + // every leaf node and twice for every non-leaf node (first with + // entering=true, then with entering=false). The method should write its + // rendition of the node to the supplied writer w. + RenderNode(w io.Writer, node *Node, entering bool) WalkStatus + + // RenderHeader is a method that allows the renderer to produce some + // content preceding the main body of the output document. The header is + // understood in the broad sense here. For example, the default HTML + // renderer will write not only the HTML document preamble, but also the + // table of contents if it was requested. + // + // The method will be passed an entire document tree, in case a particular + // implementation needs to inspect it to produce output. + // + // The output should be written to the supplied writer w. If your + // implementation has no header to write, supply an empty implementation. + RenderHeader(w io.Writer, ast *Node) + + // RenderFooter is a symmetric counterpart of RenderHeader. + RenderFooter(w io.Writer, ast *Node) +} + +// Callback functions for inline parsing. One such function is defined +// for each character that triggers a response when parsing inline data. +type inlineParser func(p *Markdown, data []byte, offset int) (int, *Node) + +// Markdown is a type that holds extensions and the runtime state used by +// Parse, and the renderer. You can not use it directly, construct it with New. +type Markdown struct { + renderer Renderer + referenceOverride ReferenceOverrideFunc + refs map[string]*reference + inlineCallback [256]inlineParser + extensions Extensions + nesting int + maxNesting int + insideLink bool + + // Footnotes need to be ordered as well as available to quickly check for + // presence. If a ref is also a footnote, it's stored both in refs and here + // in notes. Slice is nil if footnotes not enabled. + notes []*reference + + doc *Node + tip *Node // = doc + oldTip *Node + lastMatchedContainer *Node // = doc + allClosed bool +} + +func (p *Markdown) getRef(refid string) (ref *reference, found bool) { + if p.referenceOverride != nil { + r, overridden := p.referenceOverride(refid) + if overridden { + if r == nil { + return nil, false + } + return &reference{ + link: []byte(r.Link), + title: []byte(r.Title), + noteID: 0, + hasBlock: false, + text: []byte(r.Text)}, true + } + } + // refs are case insensitive + ref, found = p.refs[strings.ToLower(refid)] + return ref, found +} + +func (p *Markdown) finalize(block *Node) { + above := block.Parent + block.open = false + p.tip = above +} + +func (p *Markdown) addChild(node NodeType, offset uint32) *Node { + return p.addExistingChild(NewNode(node), offset) +} + +func (p *Markdown) addExistingChild(node *Node, offset uint32) *Node { + for !p.tip.canContain(node.Type) { + p.finalize(p.tip) + } + p.tip.AppendChild(node) + p.tip = node + return node +} + +func (p *Markdown) closeUnmatchedBlocks() { + if !p.allClosed { + for p.oldTip != p.lastMatchedContainer { + parent := p.oldTip.Parent + p.finalize(p.oldTip) + p.oldTip = parent + } + p.allClosed = true + } +} + +// +// +// Public interface +// +// + +// Reference represents the details of a link. +// See the documentation in Options for more details on use-case. +type Reference struct { + // Link is usually the URL the reference points to. + Link string + // Title is the alternate text describing the link in more detail. + Title string + // Text is the optional text to override the ref with if the syntax used was + // [refid][] + Text string +} + +// ReferenceOverrideFunc is expected to be called with a reference string and +// return either a valid Reference type that the reference string maps to or +// nil. If overridden is false, the default reference logic will be executed. +// See the documentation in Options for more details on use-case. +type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool) + +// New constructs a Markdown processor. You can use the same With* functions as +// for Run() to customize parser's behavior and the renderer. +func New(opts ...Option) *Markdown { + var p Markdown + for _, opt := range opts { + opt(&p) + } + p.refs = make(map[string]*reference) + p.maxNesting = 16 + p.insideLink = false + docNode := NewNode(Document) + p.doc = docNode + p.tip = docNode + p.oldTip = docNode + p.lastMatchedContainer = docNode + p.allClosed = true + // register inline parsers + p.inlineCallback[' '] = maybeLineBreak + p.inlineCallback['*'] = emphasis + p.inlineCallback['_'] = emphasis + if p.extensions&Strikethrough != 0 { + p.inlineCallback['~'] = emphasis + } + p.inlineCallback['`'] = codeSpan + p.inlineCallback['\n'] = lineBreak + p.inlineCallback['['] = link + p.inlineCallback['<'] = leftAngle + p.inlineCallback['\\'] = escape + p.inlineCallback['&'] = entity + p.inlineCallback['!'] = maybeImage + p.inlineCallback['^'] = maybeInlineFootnote + if p.extensions&Autolink != 0 { + p.inlineCallback['h'] = maybeAutoLink + p.inlineCallback['m'] = maybeAutoLink + p.inlineCallback['f'] = maybeAutoLink + p.inlineCallback['H'] = maybeAutoLink + p.inlineCallback['M'] = maybeAutoLink + p.inlineCallback['F'] = maybeAutoLink + } + if p.extensions&Footnotes != 0 { + p.notes = make([]*reference, 0) + } + return &p +} + +// Option customizes the Markdown processor's default behavior. +type Option func(*Markdown) + +// WithRenderer allows you to override the default renderer. +func WithRenderer(r Renderer) Option { + return func(p *Markdown) { + p.renderer = r + } +} + +// WithExtensions allows you to pick some of the many extensions provided by +// Blackfriday. You can bitwise OR them. +func WithExtensions(e Extensions) Option { + return func(p *Markdown) { + p.extensions = e + } +} + +// WithNoExtensions turns off all extensions and custom behavior. +func WithNoExtensions() Option { + return func(p *Markdown) { + p.extensions = NoExtensions + p.renderer = NewHTMLRenderer(HTMLRendererParameters{ + Flags: HTMLFlagsNone, + }) + } +} + +// WithRefOverride sets an optional function callback that is called every +// time a reference is resolved. +// +// In Markdown, the link reference syntax can be made to resolve a link to +// a reference instead of an inline URL, in one of the following ways: +// +// * [link text][refid] +// * [refid][] +// +// Usually, the refid is defined at the bottom of the Markdown document. If +// this override function is provided, the refid is passed to the override +// function first, before consulting the defined refids at the bottom. If +// the override function indicates an override did not occur, the refids at +// the bottom will be used to fill in the link details. +func WithRefOverride(o ReferenceOverrideFunc) Option { + return func(p *Markdown) { + p.referenceOverride = o + } +} + +// Run is the main entry point to Blackfriday. It parses and renders a +// block of markdown-encoded text. +// +// The simplest invocation of Run takes one argument, input: +// output := Run(input) +// This will parse the input with CommonExtensions enabled and render it with +// the default HTMLRenderer (with CommonHTMLFlags). +// +// Variadic arguments opts can customize the default behavior. Since Markdown +// type does not contain exported fields, you can not use it directly. Instead, +// use the With* functions. For example, this will call the most basic +// functionality, with no extensions: +// output := Run(input, WithNoExtensions()) +// +// You can use any number of With* arguments, even contradicting ones. They +// will be applied in order of appearance and the latter will override the +// former: +// output := Run(input, WithNoExtensions(), WithExtensions(exts), +// WithRenderer(yourRenderer)) +func Run(input []byte, opts ...Option) []byte { + r := NewHTMLRenderer(HTMLRendererParameters{ + Flags: CommonHTMLFlags, + }) + optList := []Option{WithRenderer(r), WithExtensions(CommonExtensions)} + optList = append(optList, opts...) + parser := New(optList...) + ast := parser.Parse(input) + var buf bytes.Buffer + parser.renderer.RenderHeader(&buf, ast) + ast.Walk(func(node *Node, entering bool) WalkStatus { + return parser.renderer.RenderNode(&buf, node, entering) + }) + parser.renderer.RenderFooter(&buf, ast) + return buf.Bytes() +} + +// Parse is an entry point to the parsing part of Blackfriday. It takes an +// input markdown document and produces a syntax tree for its contents. This +// tree can then be rendered with a default or custom renderer, or +// analyzed/transformed by the caller to whatever non-standard needs they have. +// The return value is the root node of the syntax tree. +func (p *Markdown) Parse(input []byte) *Node { + p.block(input) + // Walk the tree and finish up some of unfinished blocks + for p.tip != nil { + p.finalize(p.tip) + } + // Walk the tree again and process inline markdown in each block + p.doc.Walk(func(node *Node, entering bool) WalkStatus { + if node.Type == Paragraph || node.Type == Heading || node.Type == TableCell { + p.inline(node, node.content) + node.content = nil + } + return GoToNext + }) + p.parseRefsToAST() + return p.doc +} + +func (p *Markdown) parseRefsToAST() { + if p.extensions&Footnotes == 0 || len(p.notes) == 0 { + return + } + p.tip = p.doc + block := p.addBlock(List, nil) + block.IsFootnotesList = true + block.ListFlags = ListTypeOrdered + flags := ListItemBeginningOfList + // Note: this loop is intentionally explicit, not range-form. This is + // because the body of the loop will append nested footnotes to p.notes and + // we need to process those late additions. Range form would only walk over + // the fixed initial set. + for i := 0; i < len(p.notes); i++ { + ref := p.notes[i] + p.addExistingChild(ref.footnote, 0) + block := ref.footnote + block.ListFlags = flags | ListTypeOrdered + block.RefLink = ref.link + if ref.hasBlock { + flags |= ListItemContainsBlock + p.block(ref.title) + } else { + p.inline(block, ref.title) + } + flags &^= ListItemBeginningOfList | ListItemContainsBlock + } + above := block.Parent + finalizeList(block) + p.tip = above + block.Walk(func(node *Node, entering bool) WalkStatus { + if node.Type == Paragraph || node.Type == Heading { + p.inline(node, node.content) + node.content = nil + } + return GoToNext + }) +} + +// +// Link references +// +// This section implements support for references that (usually) appear +// as footnotes in a document, and can be referenced anywhere in the document. +// The basic format is: +// +// [1]: http://www.google.com/ "Google" +// [2]: http://www.github.com/ "Github" +// +// Anywhere in the document, the reference can be linked by referring to its +// label, i.e., 1 and 2 in this example, as in: +// +// This library is hosted on [Github][2], a git hosting site. +// +// Actual footnotes as specified in Pandoc and supported by some other Markdown +// libraries such as php-markdown are also taken care of. They look like this: +// +// This sentence needs a bit of further explanation.[^note] +// +// [^note]: This is the explanation. +// +// Footnotes should be placed at the end of the document in an ordered list. +// Inline footnotes such as: +// +// Inline footnotes^[Not supported.] also exist. +// +// are not yet supported. + +// reference holds all information necessary for a reference-style links or +// footnotes. +// +// Consider this markdown with reference-style links: +// +// [link][ref] +// +// [ref]: /url/ "tooltip title" +// +// It will be ultimately converted to this HTML: +// +// <p><a href=\"/url/\" title=\"title\">link</a></p> +// +// And a reference structure will be populated as follows: +// +// p.refs["ref"] = &reference{ +// link: "/url/", +// title: "tooltip title", +// } +// +// Alternatively, reference can contain information about a footnote. Consider +// this markdown: +// +// Text needing a footnote.[^a] +// +// [^a]: This is the note +// +// A reference structure will be populated as follows: +// +// p.refs["a"] = &reference{ +// link: "a", +// title: "This is the note", +// noteID: <some positive int>, +// } +// +// TODO: As you can see, it begs for splitting into two dedicated structures +// for refs and for footnotes. +type reference struct { + link []byte + title []byte + noteID int // 0 if not a footnote ref + hasBlock bool + footnote *Node // a link to the Item node within a list of footnotes + + text []byte // only gets populated by refOverride feature with Reference.Text +} + +func (r *reference) String() string { + return fmt.Sprintf("{link: %q, title: %q, text: %q, noteID: %d, hasBlock: %v}", + r.link, r.title, r.text, r.noteID, r.hasBlock) +} + +// Check whether or not data starts with a reference link. +// If so, it is parsed and stored in the list of references +// (in the render struct). +// Returns the number of bytes to skip to move past it, +// or zero if the first line is not a reference. +func isReference(p *Markdown, data []byte, tabSize int) int { + // up to 3 optional leading spaces + if len(data) < 4 { + return 0 + } + i := 0 + for i < 3 && data[i] == ' ' { + i++ + } + + noteID := 0 + + // id part: anything but a newline between brackets + if data[i] != '[' { + return 0 + } + i++ + if p.extensions&Footnotes != 0 { + if i < len(data) && data[i] == '^' { + // we can set it to anything here because the proper noteIds will + // be assigned later during the second pass. It just has to be != 0 + noteID = 1 + i++ + } + } + idOffset := i + for i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != ']' { + i++ + } + if i >= len(data) || data[i] != ']' { + return 0 + } + idEnd := i + // footnotes can have empty ID, like this: [^], but a reference can not be + // empty like this: []. Break early if it's not a footnote and there's no ID + if noteID == 0 && idOffset == idEnd { + return 0 + } + // spacer: colon (space | tab)* newline? (space | tab)* + i++ + if i >= len(data) || data[i] != ':' { + return 0 + } + i++ + for i < len(data) && (data[i] == ' ' || data[i] == '\t') { + i++ + } + if i < len(data) && (data[i] == '\n' || data[i] == '\r') { + i++ + if i < len(data) && data[i] == '\n' && data[i-1] == '\r' { + i++ + } + } + for i < len(data) && (data[i] == ' ' || data[i] == '\t') { + i++ + } + if i >= len(data) { + return 0 + } + + var ( + linkOffset, linkEnd int + titleOffset, titleEnd int + lineEnd int + raw []byte + hasBlock bool + ) + + if p.extensions&Footnotes != 0 && noteID != 0 { + linkOffset, linkEnd, raw, hasBlock = scanFootnote(p, data, i, tabSize) + lineEnd = linkEnd + } else { + linkOffset, linkEnd, titleOffset, titleEnd, lineEnd = scanLinkRef(p, data, i) + } + if lineEnd == 0 { + return 0 + } + + // a valid ref has been found + + ref := &reference{ + noteID: noteID, + hasBlock: hasBlock, + } + + if noteID > 0 { + // reusing the link field for the id since footnotes don't have links + ref.link = data[idOffset:idEnd] + // if footnote, it's not really a title, it's the contained text + ref.title = raw + } else { + ref.link = data[linkOffset:linkEnd] + ref.title = data[titleOffset:titleEnd] + } + + // id matches are case-insensitive + id := string(bytes.ToLower(data[idOffset:idEnd])) + + p.refs[id] = ref + + return lineEnd +} + +func scanLinkRef(p *Markdown, data []byte, i int) (linkOffset, linkEnd, titleOffset, titleEnd, lineEnd int) { + // link: whitespace-free sequence, optionally between angle brackets + if data[i] == '<' { + i++ + } + linkOffset = i + for i < len(data) && data[i] != ' ' && data[i] != '\t' && data[i] != '\n' && data[i] != '\r' { + i++ + } + linkEnd = i + if data[linkOffset] == '<' && data[linkEnd-1] == '>' { + linkOffset++ + linkEnd-- + } + + // optional spacer: (space | tab)* (newline | '\'' | '"' | '(' ) + for i < len(data) && (data[i] == ' ' || data[i] == '\t') { + i++ + } + if i < len(data) && data[i] != '\n' && data[i] != '\r' && data[i] != '\'' && data[i] != '"' && data[i] != '(' { + return + } + + // compute end-of-line + if i >= len(data) || data[i] == '\r' || data[i] == '\n' { + lineEnd = i + } + if i+1 < len(data) && data[i] == '\r' && data[i+1] == '\n' { + lineEnd++ + } + + // optional (space|tab)* spacer after a newline + if lineEnd > 0 { + i = lineEnd + 1 + for i < len(data) && (data[i] == ' ' || data[i] == '\t') { + i++ + } + } + + // optional title: any non-newline sequence enclosed in '"() alone on its line + if i+1 < len(data) && (data[i] == '\'' || data[i] == '"' || data[i] == '(') { + i++ + titleOffset = i + + // look for EOL + for i < len(data) && data[i] != '\n' && data[i] != '\r' { + i++ + } + if i+1 < len(data) && data[i] == '\n' && data[i+1] == '\r' { + titleEnd = i + 1 + } else { + titleEnd = i + } + + // step back + i-- + for i > titleOffset && (data[i] == ' ' || data[i] == '\t') { + i-- + } + if i > titleOffset && (data[i] == '\'' || data[i] == '"' || data[i] == ')') { + lineEnd = titleEnd + titleEnd = i + } + } + + return +} + +// The first bit of this logic is the same as Parser.listItem, but the rest +// is much simpler. This function simply finds the entire block and shifts it +// over by one tab if it is indeed a block (just returns the line if it's not). +// blockEnd is the end of the section in the input buffer, and contents is the +// extracted text that was shifted over one tab. It will need to be rendered at +// the end of the document. +func scanFootnote(p *Markdown, data []byte, i, indentSize int) (blockStart, blockEnd int, contents []byte, hasBlock bool) { + if i == 0 || len(data) == 0 { + return + } + + // skip leading whitespace on first line + for i < len(data) && data[i] == ' ' { + i++ + } + + blockStart = i + + // find the end of the line + blockEnd = i + for i < len(data) && data[i-1] != '\n' { + i++ + } + + // get working buffer + var raw bytes.Buffer + + // put the first line into the working buffer + raw.Write(data[blockEnd:i]) + blockEnd = i + + // process the following lines + containsBlankLine := false + +gatherLines: + for blockEnd < len(data) { + i++ + + // find the end of this line + for i < len(data) && data[i-1] != '\n' { + i++ + } + + // if it is an empty line, guess that it is part of this item + // and move on to the next line + if p.isEmpty(data[blockEnd:i]) > 0 { + containsBlankLine = true + blockEnd = i + continue + } + + n := 0 + if n = isIndented(data[blockEnd:i], indentSize); n == 0 { + // this is the end of the block. + // we don't want to include this last line in the index. + break gatherLines + } + + // if there were blank lines before this one, insert a new one now + if containsBlankLine { + raw.WriteByte('\n') + containsBlankLine = false + } + + // get rid of that first tab, write to buffer + raw.Write(data[blockEnd+n : i]) + hasBlock = true + + blockEnd = i + } + + if data[blockEnd-1] != '\n' { + raw.WriteByte('\n') + } + + contents = raw.Bytes() + + return +} + +// +// +// Miscellaneous helper functions +// +// + +// Test if a character is a punctuation symbol. +// Taken from a private function in regexp in the stdlib. +func ispunct(c byte) bool { + for _, r := range []byte("!\"#$%&'()*+,-./:;<=>?@[\\]^_`{|}~") { + if c == r { + return true + } + } + return false +} + +// Test if a character is a whitespace character. +func isspace(c byte) bool { + return c == ' ' || c == '\t' || c == '\n' || c == '\r' || c == '\f' || c == '\v' +} + +// Test if a character is letter. +func isletter(c byte) bool { + return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') +} + +// Test if a character is a letter or a digit. +// TODO: check when this is looking for ASCII alnum and when it should use unicode +func isalnum(c byte) bool { + return (c >= '0' && c <= '9') || isletter(c) +} + +// Replace tab characters with spaces, aligning to the next TAB_SIZE column. +// always ends output with a newline +func expandTabs(out *bytes.Buffer, line []byte, tabSize int) { + // first, check for common cases: no tabs, or only tabs at beginning of line + i, prefix := 0, 0 + slowcase := false + for i = 0; i < len(line); i++ { + if line[i] == '\t' { + if prefix == i { + prefix++ + } else { + slowcase = true + break + } + } + } + + // no need to decode runes if all tabs are at the beginning of the line + if !slowcase { + for i = 0; i < prefix*tabSize; i++ { + out.WriteByte(' ') + } + out.Write(line[prefix:]) + return + } + + // the slow case: we need to count runes to figure out how + // many spaces to insert for each tab + column := 0 + i = 0 + for i < len(line) { + start := i + for i < len(line) && line[i] != '\t' { + _, size := utf8.DecodeRune(line[i:]) + i += size + column++ + } + + if i > start { + out.Write(line[start:i]) + } + + if i >= len(line) { + break + } + + for { + out.WriteByte(' ') + column++ + if column%tabSize == 0 { + break + } + } + + i++ + } +} + +// Find if a line counts as indented or not. +// Returns number of characters the indent is (0 = not indented). +func isIndented(data []byte, indentSize int) int { + if len(data) == 0 { + return 0 + } + if data[0] == '\t' { + return 1 + } + if len(data) < indentSize { + return 0 + } + for i := 0; i < indentSize; i++ { + if data[i] != ' ' { + return 0 + } + } + return indentSize +} + +// Create a url-safe slug for fragments +func slugify(in []byte) []byte { + if len(in) == 0 { + return in + } + out := make([]byte, 0, len(in)) + sym := false + + for _, ch := range in { + if isalnum(ch) { + sym = false + out = append(out, ch) + } else if sym { + continue + } else { + out = append(out, '-') + sym = true + } + } + var a, b int + var ch byte + for a, ch = range out { + if ch != '-' { + break + } + } + for b = len(out) - 1; b > 0; b-- { + if out[b] != '-' { + break + } + } + return out[a : b+1] +} |