gotosocial/vendor/github.com/russross/blackfriday/v2/markdown.go
Tobi Smethurst 98263a7de6
Grand test fixup (#138)
* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig
2021-08-12 21:03:24 +02:00

951 lines
26 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.
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": {},
"del": {},
"div": {},
"dl": {},
"fieldset": {},
"form": {},
"h1": {},
"h2": {},
"h3": {},
"h4": {},
"h5": {},
"h6": {},
"iframe": {},
"ins": {},
"math": {},
"noscript": {},
"ol": {},
"pre": {},
"p": {},
"script": {},
"style": {},
"table": {},
"ul": {},
// HTML5
"address": {},
"article": {},
"aside": {},
"canvas": {},
"figcaption": {},
"figure": {},
"footer": {},
"header": {},
"hgroup": {},
"main": {},
"nav": {},
"output": {},
"progress": {},
"section": {},
"video": {},
}
// 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.
// Finally, there are inline footnotes such as:
//
// Inline footnotes^[Also supported.] provide a quick inline explanation,
// but are rendered at the bottom of the document.
//
// 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 ishorizontalspace(c) || isverticalspace(c)
}
// Test if a character is a horizontal whitespace character.
func ishorizontalspace(c byte) bool {
return c == ' ' || c == '\t'
}
// Test if a character is a vertical character.
func isverticalspace(c byte) bool {
return 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]
}