go-org-orgwiki/org/inline.go
Niklas Fasching da99094e20 Fix explicit line break parsing
It's possible for the input to end right after the explicit line break,
i.e. after the second \. This currently leads to an out of range index into
input (as the for loop starts with start+2 and [start:start+1] is the \\).
2019-01-12 20:08:17 +01:00

315 lines
9.2 KiB
Go

package org
import (
"fmt"
"path"
"regexp"
"strings"
"time"
"unicode"
)
type Text struct {
Content string
IsRaw bool
}
type LineBreak struct{ Count int }
type ExplicitLineBreak struct{}
type StatisticToken struct{ Content string }
type Timestamp struct {
Time time.Time
IsDate bool
Interval string
}
type Emphasis struct {
Kind string
Content []Node
}
type FootnoteLink struct {
Name string
Definition *FootnoteDefinition
}
type RegularLink struct {
Protocol string
Description []Node
URL string
AutoLink bool
}
var validURLCharacters = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-._~:/?#[]@!$&'()*+,;="
var autolinkProtocols = regexp.MustCompile(`^(https?|ftp|file)$`)
var imageExtensionRegexp = regexp.MustCompile(`^[.](png|gif|jpe?g|svg|tiff?)$`)
var videoExtensionRegexp = regexp.MustCompile(`^[.](webm|mp4)$`)
var subScriptSuperScriptRegexp = regexp.MustCompile(`^([_^]){([^{}]+?)}`)
var timestampRegexp = regexp.MustCompile(`^<(\d{4}-\d{2}-\d{2})( [A-Za-z]+)?( \d{2}:\d{2})?( \+\d+[dwmy])?>`)
var footnoteRegexp = regexp.MustCompile(`^\[fn:([\w-]+?)(:(.*?))?\]`)
var statisticsTokenRegexp = regexp.MustCompile(`^\[(\d+/\d+|\d+%)\]`)
var timestampFormat = "2006-01-02 Mon 15:04"
var datestampFormat = "2006-01-02 Mon"
func (d *Document) parseInline(input string) (nodes []Node) {
previous, current := 0, 0
for current < len(input) {
rewind, consumed, node := 0, 0, (Node)(nil)
switch input[current] {
case '^':
consumed, node = d.parseSubOrSuperScript(input, current)
case '_':
consumed, node = d.parseSubScriptOrEmphasis(input, current)
case '*', '/', '+':
consumed, node = d.parseEmphasis(input, current, false)
case '=', '~':
consumed, node = d.parseEmphasis(input, current, true)
case '[':
consumed, node = d.parseOpeningBracket(input, current)
case '<':
consumed, node = d.parseTimestamp(input, current)
case '\\':
consumed, node = d.parseExplicitLineBreak(input, current)
case '\n':
consumed, node = d.parseLineBreak(input, current)
case ':':
rewind, consumed, node = d.parseAutoLink(input, current)
current -= rewind
}
if consumed != 0 {
if current > previous {
nodes = append(nodes, Text{input[previous:current], false})
}
if node != nil {
nodes = append(nodes, node)
}
current += consumed
previous = current
} else {
current++
}
}
if previous < len(input) {
nodes = append(nodes, Text{input[previous:], false})
}
return nodes
}
func (d *Document) parseRawInline(input string) (nodes []Node) {
previous, current := 0, 0
for current < len(input) {
if input[current] == '\n' {
consumed, node := d.parseLineBreak(input, current)
if current > previous {
nodes = append(nodes, Text{input[previous:current], true})
}
nodes = append(nodes, node)
current += consumed
previous = current
} else {
current++
}
}
if previous < len(input) {
nodes = append(nodes, Text{input[previous:], true})
}
return nodes
}
func (d *Document) parseLineBreak(input string, start int) (int, Node) {
i := start
for ; i < len(input) && input[i] == '\n'; i++ {
}
return i - start, LineBreak{i - start}
}
func (d *Document) parseExplicitLineBreak(input string, start int) (int, Node) {
if start == 0 || input[start-1] == '\n' || start+2 >= len(input) || input[start+1] != '\\' {
return 0, nil
}
for i := start + 2; unicode.IsSpace(rune(input[i])); i++ {
if i >= len(input) || input[i] == '\n' {
return i + 1 - start, ExplicitLineBreak{}
}
}
return 0, nil
}
func (d *Document) parseSubOrSuperScript(input string, start int) (int, Node) {
if m := subScriptSuperScriptRegexp.FindStringSubmatch(input[start:]); m != nil {
return len(m[2]) + 3, Emphasis{m[1] + "{}", []Node{Text{m[2], false}}}
}
return 0, nil
}
func (d *Document) parseSubScriptOrEmphasis(input string, start int) (int, Node) {
if consumed, node := d.parseSubOrSuperScript(input, start); consumed != 0 {
return consumed, node
}
return d.parseEmphasis(input, start, false)
}
func (d *Document) parseOpeningBracket(input string, start int) (int, Node) {
if len(input[start:]) >= 2 && input[start] == '[' && input[start+1] == '[' {
return d.parseRegularLink(input, start)
} else if footnoteRegexp.MatchString(input[start:]) {
return d.parseFootnoteReference(input, start)
} else if statisticsTokenRegexp.MatchString(input[start:]) {
return d.parseStatisticToken(input, start)
}
return 0, nil
}
func (d *Document) parseFootnoteReference(input string, start int) (int, Node) {
if m := footnoteRegexp.FindStringSubmatch(input[start:]); m != nil {
name, definition := m[1], m[3]
link := FootnoteLink{name, nil}
if definition != "" {
link.Definition = &FootnoteDefinition{name, []Node{Paragraph{d.parseInline(definition)}}, true}
d.addFootnote(name, link.Definition)
}
return len(m[0]), link
}
return 0, nil
}
func (d *Document) parseStatisticToken(input string, start int) (int, Node) {
if m := statisticsTokenRegexp.FindStringSubmatch(input[start:]); m != nil {
return len(m[1]) + 2, StatisticToken{m[1]}
}
return 0, nil
}
func (d *Document) parseAutoLink(input string, start int) (int, int, Node) {
if !d.AutoLink || start == 0 || len(input[start:]) < 3 || input[start:start+3] != "://" {
return 0, 0, nil
}
protocolStart, protocol := start-1, ""
for ; protocolStart > 0; protocolStart-- {
if !unicode.IsLetter(rune(input[protocolStart])) {
protocolStart++
break
}
}
if m := autolinkProtocols.FindStringSubmatch(input[protocolStart:start]); m != nil {
protocol = m[1]
} else {
return 0, 0, nil
}
end := start
for ; end < len(input) && strings.ContainsRune(validURLCharacters, rune(input[end])); end++ {
}
path := input[start:end]
if path == "://" {
return 0, 0, nil
}
return len(protocol), len(path + protocol), RegularLink{protocol, nil, protocol + path, true}
}
func (d *Document) parseRegularLink(input string, start int) (int, Node) {
input = input[start:]
if len(input) < 3 || input[:2] != "[[" || input[2] == '[' {
return 0, nil
}
end := strings.Index(input, "]]")
if end == -1 {
return 0, nil
}
rawLinkParts := strings.Split(input[2:end], "][")
description, link := ([]Node)(nil), rawLinkParts[0]
if len(rawLinkParts) == 2 {
link, description = rawLinkParts[0], d.parseInline(rawLinkParts[1])
}
if strings.ContainsRune(link, '\n') {
return 0, nil
}
consumed := end + 2
protocol, linkParts := "", strings.SplitN(link, ":", 2)
if len(linkParts) == 2 {
protocol = linkParts[0]
}
return consumed, RegularLink{protocol, description, link, false}
}
func (d *Document) parseTimestamp(input string, start int) (int, Node) {
if m := timestampRegexp.FindStringSubmatch(input[start:]); m != nil {
ddmmyy, hhmm, interval, isDate := m[1], m[3], strings.TrimSpace(m[4]), false
if hhmm == "" {
hhmm, isDate = "00:00", true
}
t, err := time.Parse(timestampFormat, fmt.Sprintf("%s Mon %s", ddmmyy, hhmm))
if err != nil {
return 0, nil
}
timestamp := Timestamp{t, isDate, interval}
return len(m[0]), timestamp
}
return 0, nil
}
func (d *Document) parseEmphasis(input string, start int, isRaw bool) (int, Node) {
marker, i := input[start], start
if !hasValidPreAndBorderChars(input, i) {
return 0, nil
}
for i, consumedNewLines := i+1, 0; i < len(input) && consumedNewLines <= d.MaxEmphasisNewLines; i++ {
if input[i] == '\n' {
consumedNewLines++
}
if input[i] == marker && i != start+1 && hasValidPostAndBorderChars(input, i) {
if isRaw {
return i + 1 - start, Emphasis{input[start : start+1], d.parseRawInline(input[start+1 : i])}
}
return i + 1 - start, Emphasis{input[start : start+1], d.parseInline(input[start+1 : i])}
}
}
return 0, nil
}
// see org-emphasis-regexp-components (emacs elisp variable)
func hasValidPreAndBorderChars(input string, i int) bool {
return (i+1 >= len(input) || isValidBorderChar(rune(input[i+1]))) && (i == 0 || isValidPreChar(rune(input[i-1])))
}
func hasValidPostAndBorderChars(input string, i int) bool {
return (i == 0 || isValidBorderChar(rune(input[i-1]))) && (i+1 >= len(input) || isValidPostChar(rune(input[i+1])))
}
func isValidPreChar(r rune) bool {
return unicode.IsSpace(r) || strings.ContainsRune(`-({'"`, r)
}
func isValidPostChar(r rune) bool {
return unicode.IsSpace(r) || strings.ContainsRune(`-.,:!?;'")}[`, r)
}
func isValidBorderChar(r rune) bool { return !unicode.IsSpace(r) }
func (l RegularLink) Kind() string {
if p := l.Protocol; l.Description != nil || (p != "" && p != "file" && p != "http" && p != "https") {
return "regular"
}
if imageExtensionRegexp.MatchString(path.Ext(l.URL)) {
return "image"
}
if videoExtensionRegexp.MatchString(path.Ext(l.URL)) {
return "video"
}
return "regular"
}
func (n Text) String() string { return orgWriter.nodesAsString(n) }
func (n LineBreak) String() string { return orgWriter.nodesAsString(n) }
func (n ExplicitLineBreak) String() string { return orgWriter.nodesAsString(n) }
func (n StatisticToken) String() string { return orgWriter.nodesAsString(n) }
func (n Emphasis) String() string { return orgWriter.nodesAsString(n) }
func (n FootnoteLink) String() string { return orgWriter.nodesAsString(n) }
func (n RegularLink) String() string { return orgWriter.nodesAsString(n) }
func (n Timestamp) String() string { return orgWriter.nodesAsString(n) }