gosora/plugin_markdown.go

381 lines
8.6 KiB
Go

package main
import (
"strings"
"github.com/Azareal/Gosora/common"
)
var markdownMaxDepth = 25 // How deep the parser will go when parsing Markdown strings
var markdownUnclosedElement []byte
var markdownBoldTagOpen []byte
var markdownBoldTagClose []byte
var markdownItalicTagOpen []byte
var markdownItalicTagClose []byte
var markdownUnderlineTagOpen []byte
var markdownUnderlineTagClose []byte
var markdownStrikeTagOpen []byte
var markdownStrikeTagClose []byte
var markdownQuoteTagOpen []byte
var markdownQuoteTagClose []byte
var markdownH1TagOpen []byte
var markdownH1TagClose []byte
func init() {
common.Plugins.Add(&common.Plugin{UName: "markdown", Name: "Markdown", Author: "Azareal", URL: "https://github.com/Azareal", Init: initMarkdown, Deactivate: deactivateMarkdown})
}
func initMarkdown(plugin *common.Plugin) error {
plugin.AddHook("parse_assign", markdownParse)
markdownUnclosedElement = []byte("<span style='color: red;'>[Unclosed Element]</span>")
markdownBoldTagOpen = []byte("<b>")
markdownBoldTagClose = []byte("</b>")
markdownItalicTagOpen = []byte("<i>")
markdownItalicTagClose = []byte("</i>")
markdownUnderlineTagOpen = []byte("<u>")
markdownUnderlineTagClose = []byte("</u>")
markdownStrikeTagOpen = []byte("<s>")
markdownStrikeTagClose = []byte("</s>")
markdownQuoteTagOpen = []byte("<blockquote>")
markdownQuoteTagClose = []byte("</blockquote>")
markdownH1TagOpen = []byte("<h2>")
markdownH1TagClose = []byte("</h2>")
return nil
}
func deactivateMarkdown(plugin *common.Plugin) {
plugin.RemoveHook("parse_assign", markdownParse)
}
// An adapter for the parser, so that the parser can call itself recursively.
// This is less for the simple Markdown elements like bold and italics and more for the really complicated ones I plan on adding at some point.
func markdownParse(msg string) string {
msg = _markdownParse(msg+" ", 0)
if msg[len(msg)-1] == ' ' {
msg = msg[:len(msg)-1]
}
return msg
}
// Under Construction!
func _markdownParse(msg string, n int) string {
if n > markdownMaxDepth {
return "<span style='color: red;'>[Markdown Error: Overflowed the max depth of 20]</span>"
}
var outbytes []byte
var lastElement int
var breaking = false
common.DebugLogf("Initial Message: %+v\n", strings.Replace(msg, "\r", "\\r", -1))
for index := 0; index < len(msg); index++ {
var simpleMatch = func(char byte, o []byte, c []byte) {
var startIndex = index
if (index + 1) >= len(msg) {
breaking = true
return
}
index++
index = markdownSkipUntilChar(msg, index, char)
if (index-(startIndex+1)) < 1 || index >= len(msg) {
breaking = true
return
}
sIndex := startIndex + 1
lIndex := index
index++
outbytes = append(outbytes, msg[lastElement:startIndex]...)
outbytes = append(outbytes, o...)
// TODO: Implement this without as many type conversions
outbytes = append(outbytes, []byte(_markdownParse(msg[sIndex:lIndex], n+1))...)
outbytes = append(outbytes, c...)
lastElement = index
index--
}
var startLine = func() {
var startIndex = index
if (index + 1) >= len(msg) /*|| (index + 2) >= len(msg)*/ {
breaking = true
return
}
index++
index = markdownSkipUntilNotChar(msg, index, 32)
if (index + 1) >= len(msg) {
breaking = true
return
}
//index++
index = markdownSkipUntilStrongSpace(msg, index)
sIndex := startIndex + 1
lIndex := index
index++
outbytes = append(outbytes, msg[lastElement:startIndex]...)
outbytes = append(outbytes, markdownH1TagOpen...)
// TODO: Implement this without as many type conversions
//fmt.Println("msg[sIndex:lIndex]:", string(msg[sIndex:lIndex]))
// TODO: Quick hack to eliminate trailing spaces...
outbytes = append(outbytes, []byte(strings.TrimSpace(_markdownParse(msg[sIndex:lIndex], n+1)))...)
outbytes = append(outbytes, markdownH1TagClose...)
lastElement = index
index--
}
switch msg[index] {
// TODO: Do something slightly less hacky for skipping URLs
case '/':
if len(msg) > (index+2) && msg[index+1] == '/' {
for ; index < len(msg) && msg[index] != ' '; index++ {
}
index--
continue
}
case '_':
simpleMatch('_', markdownUnderlineTagOpen, markdownUnderlineTagClose)
if breaking {
break
}
case '~':
simpleMatch('~', markdownStrikeTagOpen, markdownStrikeTagClose)
if breaking {
break
}
case '*':
var startIndex = index
var italic = true
var bold = false
if (index + 2) < len(msg) {
if msg[index+1] == '*' {
bold = true
index++
if msg[index+1] != '*' {
italic = false
} else {
index++
}
}
}
// Does the string terminate abruptly?
if (index + 1) >= len(msg) {
break
}
index++
index = markdownSkipUntilAsterisk(msg, index)
if index >= len(msg) {
break
}
var preBreak = func() {
outbytes = append(outbytes, msg[lastElement:startIndex]...)
lastElement = startIndex
}
sIndex := startIndex
lIndex := index
if bold && italic {
if (index + 3) >= len(msg) {
preBreak()
break
}
index += 3
sIndex += 3
} else if bold {
if (index + 2) >= len(msg) {
preBreak()
break
}
index += 2
sIndex += 2
} else {
if (index + 1) >= len(msg) {
preBreak()
break
}
index++
sIndex++
}
if lIndex <= sIndex {
preBreak()
break
}
if sIndex < 0 || lIndex < 0 {
preBreak()
break
}
outbytes = append(outbytes, msg[lastElement:startIndex]...)
if bold {
outbytes = append(outbytes, markdownBoldTagOpen...)
}
if italic {
outbytes = append(outbytes, markdownItalicTagOpen...)
}
// TODO: Implement this without as many type conversions
outbytes = append(outbytes, []byte(_markdownParse(msg[sIndex:lIndex], n+1))...)
if italic {
outbytes = append(outbytes, markdownItalicTagClose...)
}
if bold {
outbytes = append(outbytes, markdownBoldTagClose...)
}
lastElement = index
index--
case '\\':
if (index + 1) < len(msg) {
if isMarkdownStartChar(msg[index+1]) && msg[index+1] != '\\' {
outbytes = append(outbytes, msg[lastElement:index]...)
index++
lastElement = index
}
}
// TODO: Add a inline quote variant
case '`':
simpleMatch('`', markdownQuoteTagOpen, markdownQuoteTagClose)
if breaking {
break
}
case 10: // newline
if (index + 1) >= len(msg) {
break
}
index++
if msg[index] != '#' {
continue
}
startLine()
if breaking {
break
}
case '#':
if index != 0 {
continue
}
startLine()
if breaking {
break
}
}
}
if len(outbytes) == 0 {
return msg
} else if lastElement < (len(msg) - 1) {
msg = string(outbytes) + msg[lastElement:]
return msg
}
return string(outbytes)
}
func isMarkdownStartChar(char byte) bool {
return char == '\\' || char == '~' || char == '_' || char == 10 || char == '`' || char == '*'
}
func markdownFindChar(data string, index int, char byte) bool {
for ; index < len(data); index++ {
item := data[index]
if item > 32 {
return (item == char)
}
}
return false
}
func markdownSkipUntilChar(data string, index int, char byte) int {
for ; index < len(data); index++ {
if data[index] == char {
break
}
}
return index
}
func markdownSkipUntilNotChar(data string, index int, char byte) int {
for ; index < len(data); index++ {
if data[index] != char {
break
}
}
return index
}
func markdownSkipUntilStrongSpace(data string, index int) int {
var inSpace = false
for ; index < len(data); index++ {
if inSpace && data[index] == 32 {
index--
break
} else if data[index] == 32 {
inSpace = true
} else if data[index] < 32 {
break
} else {
inSpace = false
}
}
return index
}
func markdownSkipUntilAsterisk(data string, index int) int {
SwitchLoop:
for ; index < len(data); index++ {
switch data[index] {
case 10:
if ((index + 1) < len(data)) && markdownFindChar(data, index, '*') {
index = markdownSkipList(data, index)
}
case '*':
break SwitchLoop
}
}
return index
}
// plugin_markdown doesn't support lists yet, but I want it to be easy to have nested lists when we do have them
func markdownSkipList(data string, index int) int {
var lastNewline int
var datalen = len(data)
for ; index < datalen; index++ {
SkipListInnerLoop:
if data[index] == 10 {
lastNewline = index
for ; index < datalen; index++ {
if data[index] > 32 {
break
} else if data[index] == 10 {
goto SkipListInnerLoop
}
}
if index >= datalen {
if data[index] != '*' && data[index] != '-' {
if (lastNewline + 1) < datalen {
return lastNewline + 1
}
return lastNewline
}
}
}
}
return index
}