mirror of
https://codeberg.org/forgejo/forgejo
synced 2024-12-14 07:21:58 +01:00
951 lines
26 KiB
Go
951 lines
26 KiB
Go
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// Blackfriday Markdown Processor
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// Available at http://github.com/russross/blackfriday
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//
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// Copyright © 2011 Russ Ross <russ@russross.com>.
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// Distributed under the Simplified BSD License.
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// See README.md for details.
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package blackfriday
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import (
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"bytes"
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"fmt"
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"io"
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"strings"
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"unicode/utf8"
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)
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//
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// Markdown parsing and processing
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//
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// Version string of the package. Appears in the rendered document when
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// CompletePage flag is on.
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const Version = "2.0"
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// Extensions is a bitwise or'ed collection of enabled Blackfriday's
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// extensions.
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type Extensions int
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// These are the supported markdown parsing extensions.
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// OR these values together to select multiple extensions.
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const (
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NoExtensions Extensions = 0
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NoIntraEmphasis Extensions = 1 << iota // Ignore emphasis markers inside words
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Tables // Render tables
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FencedCode // Render fenced code blocks
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Autolink // Detect embedded URLs that are not explicitly marked
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Strikethrough // Strikethrough text using ~~test~~
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LaxHTMLBlocks // Loosen up HTML block parsing rules
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SpaceHeadings // Be strict about prefix heading rules
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HardLineBreak // Translate newlines into line breaks
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TabSizeEight // Expand tabs to eight spaces instead of four
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Footnotes // Pandoc-style footnotes
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NoEmptyLineBeforeBlock // No need to insert an empty line to start a (code, quote, ordered list, unordered list) block
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HeadingIDs // specify heading IDs with {#id}
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Titleblock // Titleblock ala pandoc
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AutoHeadingIDs // Create the heading ID from the text
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BackslashLineBreak // Translate trailing backslashes into line breaks
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DefinitionLists // Render definition lists
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CommonHTMLFlags HTMLFlags = UseXHTML | Smartypants |
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SmartypantsFractions | SmartypantsDashes | SmartypantsLatexDashes
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CommonExtensions Extensions = NoIntraEmphasis | Tables | FencedCode |
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Autolink | Strikethrough | SpaceHeadings | HeadingIDs |
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BackslashLineBreak | DefinitionLists
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)
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// ListType contains bitwise or'ed flags for list and list item objects.
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type ListType int
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// These are the possible flag values for the ListItem renderer.
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// Multiple flag values may be ORed together.
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// These are mostly of interest if you are writing a new output format.
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const (
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ListTypeOrdered ListType = 1 << iota
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ListTypeDefinition
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ListTypeTerm
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ListItemContainsBlock
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ListItemBeginningOfList // TODO: figure out if this is of any use now
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ListItemEndOfList
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)
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// CellAlignFlags holds a type of alignment in a table cell.
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type CellAlignFlags int
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// These are the possible flag values for the table cell renderer.
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// Only a single one of these values will be used; they are not ORed together.
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// These are mostly of interest if you are writing a new output format.
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const (
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TableAlignmentLeft CellAlignFlags = 1 << iota
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TableAlignmentRight
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TableAlignmentCenter = (TableAlignmentLeft | TableAlignmentRight)
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)
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// The size of a tab stop.
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const (
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TabSizeDefault = 4
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TabSizeDouble = 8
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)
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// blockTags is a set of tags that are recognized as HTML block tags.
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// Any of these can be included in markdown text without special escaping.
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var blockTags = map[string]struct{}{
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"blockquote": {},
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"del": {},
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"div": {},
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"dl": {},
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"fieldset": {},
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"form": {},
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"h1": {},
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"h2": {},
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"h3": {},
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"h4": {},
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"h5": {},
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"h6": {},
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"iframe": {},
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"ins": {},
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"math": {},
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"noscript": {},
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"ol": {},
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"pre": {},
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"p": {},
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"script": {},
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"style": {},
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"table": {},
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"ul": {},
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// HTML5
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"address": {},
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"article": {},
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"aside": {},
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"canvas": {},
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"figcaption": {},
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"figure": {},
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"footer": {},
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"header": {},
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"hgroup": {},
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"main": {},
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"nav": {},
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"output": {},
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"progress": {},
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"section": {},
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"video": {},
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}
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// Renderer is the rendering interface. This is mostly of interest if you are
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// implementing a new rendering format.
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//
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// Only an HTML implementation is provided in this repository, see the README
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// for external implementations.
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type Renderer interface {
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// RenderNode is the main rendering method. It will be called once for
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// every leaf node and twice for every non-leaf node (first with
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// entering=true, then with entering=false). The method should write its
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// rendition of the node to the supplied writer w.
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RenderNode(w io.Writer, node *Node, entering bool) WalkStatus
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// RenderHeader is a method that allows the renderer to produce some
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// content preceding the main body of the output document. The header is
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// understood in the broad sense here. For example, the default HTML
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// renderer will write not only the HTML document preamble, but also the
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// table of contents if it was requested.
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//
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// The method will be passed an entire document tree, in case a particular
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// implementation needs to inspect it to produce output.
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//
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// The output should be written to the supplied writer w. If your
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// implementation has no header to write, supply an empty implementation.
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RenderHeader(w io.Writer, ast *Node)
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// RenderFooter is a symmetric counterpart of RenderHeader.
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RenderFooter(w io.Writer, ast *Node)
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}
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// Callback functions for inline parsing. One such function is defined
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// for each character that triggers a response when parsing inline data.
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type inlineParser func(p *Markdown, data []byte, offset int) (int, *Node)
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// Markdown is a type that holds extensions and the runtime state used by
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// Parse, and the renderer. You can not use it directly, construct it with New.
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type Markdown struct {
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renderer Renderer
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referenceOverride ReferenceOverrideFunc
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refs map[string]*reference
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inlineCallback [256]inlineParser
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extensions Extensions
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nesting int
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maxNesting int
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insideLink bool
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// Footnotes need to be ordered as well as available to quickly check for
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// presence. If a ref is also a footnote, it's stored both in refs and here
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// in notes. Slice is nil if footnotes not enabled.
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notes []*reference
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doc *Node
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tip *Node // = doc
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oldTip *Node
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lastMatchedContainer *Node // = doc
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allClosed bool
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}
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func (p *Markdown) getRef(refid string) (ref *reference, found bool) {
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if p.referenceOverride != nil {
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r, overridden := p.referenceOverride(refid)
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if overridden {
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if r == nil {
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return nil, false
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}
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return &reference{
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link: []byte(r.Link),
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title: []byte(r.Title),
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noteID: 0,
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hasBlock: false,
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text: []byte(r.Text)}, true
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}
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}
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// refs are case insensitive
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ref, found = p.refs[strings.ToLower(refid)]
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return ref, found
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}
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func (p *Markdown) finalize(block *Node) {
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above := block.Parent
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block.open = false
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p.tip = above
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}
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func (p *Markdown) addChild(node NodeType, offset uint32) *Node {
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return p.addExistingChild(NewNode(node), offset)
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}
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func (p *Markdown) addExistingChild(node *Node, offset uint32) *Node {
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for !p.tip.canContain(node.Type) {
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p.finalize(p.tip)
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}
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p.tip.AppendChild(node)
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p.tip = node
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return node
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}
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func (p *Markdown) closeUnmatchedBlocks() {
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if !p.allClosed {
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for p.oldTip != p.lastMatchedContainer {
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parent := p.oldTip.Parent
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p.finalize(p.oldTip)
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p.oldTip = parent
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}
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p.allClosed = true
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}
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}
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//
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//
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// Public interface
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//
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//
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// Reference represents the details of a link.
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// See the documentation in Options for more details on use-case.
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type Reference struct {
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// Link is usually the URL the reference points to.
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Link string
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// Title is the alternate text describing the link in more detail.
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Title string
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// Text is the optional text to override the ref with if the syntax used was
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// [refid][]
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Text string
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}
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// ReferenceOverrideFunc is expected to be called with a reference string and
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// return either a valid Reference type that the reference string maps to or
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// nil. If overridden is false, the default reference logic will be executed.
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// See the documentation in Options for more details on use-case.
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type ReferenceOverrideFunc func(reference string) (ref *Reference, overridden bool)
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// New constructs a Markdown processor. You can use the same With* functions as
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// for Run() to customize parser's behavior and the renderer.
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func New(opts ...Option) *Markdown {
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var p Markdown
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for _, opt := range opts {
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opt(&p)
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}
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p.refs = make(map[string]*reference)
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p.maxNesting = 16
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p.insideLink = false
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docNode := NewNode(Document)
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p.doc = docNode
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p.tip = docNode
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p.oldTip = docNode
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p.lastMatchedContainer = docNode
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p.allClosed = true
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// register inline parsers
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p.inlineCallback[' '] = maybeLineBreak
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p.inlineCallback['*'] = emphasis
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p.inlineCallback['_'] = emphasis
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if p.extensions&Strikethrough != 0 {
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p.inlineCallback['~'] = emphasis
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}
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p.inlineCallback['`'] = codeSpan
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p.inlineCallback['\n'] = lineBreak
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p.inlineCallback['['] = link
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p.inlineCallback['<'] = leftAngle
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p.inlineCallback['\\'] = escape
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p.inlineCallback['&'] = entity
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p.inlineCallback['!'] = maybeImage
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p.inlineCallback['^'] = maybeInlineFootnote
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if p.extensions&Autolink != 0 {
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p.inlineCallback['h'] = maybeAutoLink
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p.inlineCallback['m'] = maybeAutoLink
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p.inlineCallback['f'] = maybeAutoLink
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p.inlineCallback['H'] = maybeAutoLink
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p.inlineCallback['M'] = maybeAutoLink
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p.inlineCallback['F'] = maybeAutoLink
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}
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if p.extensions&Footnotes != 0 {
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p.notes = make([]*reference, 0)
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}
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return &p
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}
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// Option customizes the Markdown processor's default behavior.
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type Option func(*Markdown)
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// WithRenderer allows you to override the default renderer.
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func WithRenderer(r Renderer) Option {
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return func(p *Markdown) {
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p.renderer = r
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}
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}
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// WithExtensions allows you to pick some of the many extensions provided by
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// Blackfriday. You can bitwise OR them.
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func WithExtensions(e Extensions) Option {
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return func(p *Markdown) {
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p.extensions = e
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}
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}
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// WithNoExtensions turns off all extensions and custom behavior.
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func WithNoExtensions() Option {
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return func(p *Markdown) {
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p.extensions = NoExtensions
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p.renderer = NewHTMLRenderer(HTMLRendererParameters{
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Flags: HTMLFlagsNone,
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})
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}
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}
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// WithRefOverride sets an optional function callback that is called every
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// time a reference is resolved.
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//
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// In Markdown, the link reference syntax can be made to resolve a link to
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// a reference instead of an inline URL, in one of the following ways:
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//
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// * [link text][refid]
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// * [refid][]
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//
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// Usually, the refid is defined at the bottom of the Markdown document. If
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// this override function is provided, the refid is passed to the override
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// function first, before consulting the defined refids at the bottom. If
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// the override function indicates an override did not occur, the refids at
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// the bottom will be used to fill in the link details.
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func WithRefOverride(o ReferenceOverrideFunc) Option {
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return func(p *Markdown) {
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p.referenceOverride = o
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}
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}
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// Run is the main entry point to Blackfriday. It parses and renders a
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// block of markdown-encoded text.
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//
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// The simplest invocation of Run takes one argument, input:
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// output := Run(input)
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// This will parse the input with CommonExtensions enabled and render it with
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// the default HTMLRenderer (with CommonHTMLFlags).
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//
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// Variadic arguments opts can customize the default behavior. Since Markdown
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// type does not contain exported fields, you can not use it directly. Instead,
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// use the With* functions. For example, this will call the most basic
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// functionality, with no extensions:
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// output := Run(input, WithNoExtensions())
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//
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// You can use any number of With* arguments, even contradicting ones. They
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// will be applied in order of appearance and the latter will override the
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// former:
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// output := Run(input, WithNoExtensions(), WithExtensions(exts),
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// WithRenderer(yourRenderer))
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func Run(input []byte, opts ...Option) []byte {
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r := NewHTMLRenderer(HTMLRendererParameters{
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Flags: CommonHTMLFlags,
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})
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optList := []Option{WithRenderer(r), WithExtensions(CommonExtensions)}
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optList = append(optList, opts...)
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parser := New(optList...)
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ast := parser.Parse(input)
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var buf bytes.Buffer
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parser.renderer.RenderHeader(&buf, ast)
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ast.Walk(func(node *Node, entering bool) WalkStatus {
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return parser.renderer.RenderNode(&buf, node, entering)
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})
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parser.renderer.RenderFooter(&buf, ast)
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return buf.Bytes()
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}
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// Parse is an entry point to the parsing part of Blackfriday. It takes an
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// input markdown document and produces a syntax tree for its contents. This
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// tree can then be rendered with a default or custom renderer, or
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// analyzed/transformed by the caller to whatever non-standard needs they have.
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// The return value is the root node of the syntax tree.
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func (p *Markdown) Parse(input []byte) *Node {
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p.block(input)
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// Walk the tree and finish up some of unfinished blocks
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for p.tip != nil {
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p.finalize(p.tip)
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}
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// Walk the tree again and process inline markdown in each block
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p.doc.Walk(func(node *Node, entering bool) WalkStatus {
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if node.Type == Paragraph || node.Type == Heading || node.Type == TableCell {
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p.inline(node, node.content)
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node.content = nil
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}
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return GoToNext
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})
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p.parseRefsToAST()
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return p.doc
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}
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func (p *Markdown) parseRefsToAST() {
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if p.extensions&Footnotes == 0 || len(p.notes) == 0 {
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return
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}
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p.tip = p.doc
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block := p.addBlock(List, nil)
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block.IsFootnotesList = true
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block.ListFlags = ListTypeOrdered
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flags := ListItemBeginningOfList
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// Note: this loop is intentionally explicit, not range-form. This is
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// because the body of the loop will append nested footnotes to p.notes and
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// we need to process those late additions. Range form would only walk over
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// the fixed initial set.
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for i := 0; i < len(p.notes); i++ {
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ref := p.notes[i]
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p.addExistingChild(ref.footnote, 0)
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block := ref.footnote
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block.ListFlags = flags | ListTypeOrdered
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block.RefLink = ref.link
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if ref.hasBlock {
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flags |= ListItemContainsBlock
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p.block(ref.title)
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} 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]
|
||
|
}
|