--- /dev/null
+package net.pterodactylus.sone.text
+
+import freenet.keys.FreenetURI
+import freenet.support.Base64
+import net.pterodactylus.sone.data.Sone
+import net.pterodactylus.sone.data.impl.IdOnlySone
+import net.pterodactylus.sone.database.PostProvider
+import net.pterodactylus.sone.database.SoneProvider
+import net.pterodactylus.sone.text.LinkType.CHK
+import net.pterodactylus.sone.text.LinkType.FREEMAIL
+import net.pterodactylus.sone.text.LinkType.HTTP
+import net.pterodactylus.sone.text.LinkType.HTTPS
+import net.pterodactylus.sone.text.LinkType.KSK
+import net.pterodactylus.sone.text.LinkType.POST
+import net.pterodactylus.sone.text.LinkType.SONE
+import net.pterodactylus.sone.text.LinkType.SSK
+import net.pterodactylus.sone.text.LinkType.USK
+import net.pterodactylus.sone.utils.let
+import org.bitpedia.util.Base32
+import java.net.MalformedURLException
+
+/**
+ * [Parser] implementation that can recognize Freenet URIs.
+ */
+class SoneTextParser(private val soneProvider: SoneProvider?, private val postProvider: PostProvider?) {
+
+ fun parse(source: String, context: SoneTextParserContext?) =
+ source.split("\n")
+ .dropWhile { it.trim() == "" }
+ .dropLastWhile { it.trim() == "" }
+ .mergeMultipleEmptyLines()
+ .flatMap { splitLineIntoParts(it, context) }
+ .removeEmptyPlainTextParts()
+ .mergeAdjacentPlainTextParts()
+
+ private fun splitLineIntoParts(line: String, context: SoneTextParserContext?) =
+ generateSequence(PlainTextPart("") as Part to line) { remainder ->
+ if (remainder.second == "")
+ null
+ else
+ LinkType.values()
+ .mapNotNull { it.findNext(remainder.second) }
+ .minBy { it.position }
+ .let {
+ when {
+ it == null -> PlainTextPart(remainder.second) to ""
+ it.position == 0 -> it.toPart(context) to it.remainder
+ else -> PlainTextPart(remainder.second.substring(0, it.position)) to (it.link + it.remainder)
+ }
+ }
+ }.map { it.first }.toList()
+
+ private fun NextLink.toPart(context: SoneTextParserContext?) = when (linkType) {
+ KSK, CHK -> try {
+ FreenetURI(link).let { freenetUri ->
+ FreenetLinkPart(
+ link,
+ if (freenetUri.isKSK) {
+ freenetUri.guessableKey
+ } else {
+ freenetUri.metaString ?: freenetUri.docName ?: link.substring(0, 9)
+ },
+ link.split('?').first()
+ )
+ }
+ } catch (e: MalformedURLException) {
+ PlainTextPart(link)
+ }
+ SSK, USK ->
+ try {
+ FreenetLinkPart(link, FreenetURI(link).docName, trusted = context?.routingKey?.contentEquals(FreenetURI(link).routingKey) == true)
+ } catch (e: MalformedURLException) {
+ PlainTextPart(link)
+ }
+ SONE -> link.substring(7).let { SonePart(soneProvider?.getSone(it)?.orNull() ?: IdOnlySone(it)) }
+ POST -> postProvider?.getPost(link.substring(7))?.let { PostPart(it) } ?: PlainTextPart(link)
+ FREEMAIL -> link.indexOf('@').let { atSign ->
+ link.substring(atSign + 1, link.length - 9).let { freemailId ->
+ FreemailPart(link.substring(0, atSign), freemailId, freemailId.decodedId)
+ }
+ }
+ HTTP, HTTPS -> LinkPart(link, link
+ .withoutProtocol
+ .withoutWwwPrefix
+ .withoutUrlParameters
+ .withoutMiddlePathComponents
+ .withoutTrailingSlash)
+ }
+
+}
+
+private fun List<String>.mergeMultipleEmptyLines() = fold(emptyList<String>()) { previous, current ->
+ if (previous.isEmpty()) {
+ previous + current
+ } else {
+ if ((previous.last() == "\n") && (current == "")) {
+ previous
+ } else {
+ previous + ("\n" + current)
+ }
+ }
+}
+
+private fun List<Part>.mergeAdjacentPlainTextParts() = fold(emptyList<Part>()) { parts, part ->
+ if ((parts.lastOrNull() is PlainTextPart) && (part is PlainTextPart)) {
+ parts.dropLast(1) + PlainTextPart(parts.last().text + part.text)
+ } else {
+ parts + part
+ }
+}
+
+private fun List<Part>.removeEmptyPlainTextParts() = filterNot { it == PlainTextPart("") }
+
+private val String.decodedId: String get() = Base64.encode(Base32.decode(this))
+private val String.withoutProtocol get() = substring(indexOf("//") + 2)
+private val String.withoutUrlParameters get() = split('?').first()
+
+private val String.withoutWwwPrefix
+ get() = split("/")
+ .replaceFirst { it.split(".").dropWhile { it == "www" }.joinToString(".") }
+ .joinToString("/")
+
+private fun <T> List<T>.replaceFirst(replacement: (T) -> T) = mapIndexed { index, element ->
+ if (index == 0) replacement(element) else element
+}
+
+private val String.withoutMiddlePathComponents
+ get() = split("/").let {
+ if (it.size > 2) {
+ "${it.first()}/…/${it.last()}"
+ } else {
+ it.joinToString("/")
+ }
+ }
+private val String.withoutTrailingSlash get() = if (endsWith("/")) substring(0, length - 1) else this
+private val SoneTextParserContext.routingKey: ByteArray? get() = postingSone?.routingKey
+private val Sone.routingKey: ByteArray get() = Base64.decode(id)
+
+private enum class LinkType(private val scheme: String, private val freenetLink: Boolean) {
+
+ KSK("KSK@", true),
+ CHK("CHK@", true),
+ SSK("SSK@", true),
+ USK("USK@", true),
+ HTTP("http://", false),
+ HTTPS("https://", false),
+ SONE("sone://", false) {
+ override fun validateLinkLength(length: Int) = length.takeIf { it == 50 }
+ },
+ POST("post://", false),
+ FREEMAIL("", true) {
+ override fun findNext(line: String): NextLink? {
+ val nextFreemailSuffix = line.indexOf(".freemail").takeIf { it >= 54 } ?: return null
+ if (line[nextFreemailSuffix - 53] != '@') return null
+ if (!line.substring(nextFreemailSuffix - 52, nextFreemailSuffix).matches(Regex("^[a-z2-7]*\$"))) return null
+ val firstCharacterIndex = generateSequence(nextFreemailSuffix - 53) {
+ it.minus(1).takeIf { (it >= 0) && line[it].validLocalPart }
+ }.lastOrNull() ?: return null
+ return NextLink(firstCharacterIndex, this, line.substring(firstCharacterIndex, nextFreemailSuffix + 9), line.substring(nextFreemailSuffix + 9))
+ }
+
+ private val Char.validLocalPart get() = (this in ('A'..'Z')) || (this in ('a'..'z')) || (this in ('0'..'9')) || (this == '-') || (this == '_') || (this == '.')
+ };
+
+ open fun findNext(line: String): NextLink? {
+ val nextLinkPosition = line.indexOf(scheme).takeIf { it != -1 } ?: return null
+ val endOfLink = line.substring(nextLinkPosition).findEndOfLink().validate() ?: return null
+ val link = line.substring(nextLinkPosition, nextLinkPosition + endOfLink)
+ val realNextLinkPosition = if (freenetLink && line.substring(0, nextLinkPosition).endsWith("freenet:")) nextLinkPosition - 8 else nextLinkPosition
+ return NextLink(realNextLinkPosition, this, link, line.substring(nextLinkPosition + endOfLink))
+ }
+
+ private fun String.findEndOfLink() =
+ substring(0, whitespace.find(this)?.range?.start ?: length)
+ .dropLastWhile(::isPunctuation)
+ .upToFirstUnmatchedParen()
+
+ private fun Int.validate() = validateLinkLength(this)
+ protected open fun validateLinkLength(length: Int) = length.takeIf { it > scheme.length }
+
+ private fun String.upToFirstUnmatchedParen() =
+ foldIndexed(Pair<Int, Int?>(0, null)) { index, (openParens, firstUnmatchedParen), currentChar ->
+ when (currentChar) {
+ '(' -> (openParens + 1) to firstUnmatchedParen
+ ')' -> ((openParens - 1) to (if (openParens == 0) (firstUnmatchedParen ?: index) else firstUnmatchedParen))
+ else -> openParens to firstUnmatchedParen
+ }
+ }.second ?: length
+
+}
+
+private val punctuationChars = listOf('.', ',', '?', '!')
+private fun isPunctuation(char: Char) = char in punctuationChars
+
+private val whitespace = Regex("[\\u000a\u0020\u00a0\u1680\u180e\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u200c\u200d\u202f\u205f\u2060\u2800\u3000]")
+
+private data class NextLink(val position: Int, val linkType: LinkType, val link: String, val remainder: String)
projects / Sone.git / blobdiff