Add a `UriParser` for generic URIs

package com.fsck.k9.message.html

import java.util.regex.Pattern

/**

 * Matches the URI generic syntax.

 *

 * See [RFC 3986](https://www.rfc-editor.org/rfc/rfc3986).

 */

class GenericUriParser : UriParser {

    override fun parseUri(text: CharSequence, startPos: Int): UriMatch? {

        val matcher = PATTERN.matcher(text)

        if (!matcher.find(startPos) || matcher.start() != startPos) return null

        val startIndex = matcher.start()

        val endIndex = matcher.end()

        val uri = text.subSequence(startIndex, endIndex)

        return UriMatch(startIndex, endIndex, uri)

    }

    companion object {

        private const val SCHEME = "[a-zA-Z][a-zA-Z0-9+.\\-]*"

        private const val AUTHORITY = "[a-zA-Z0-9\\-._~%!\$&'()*+,;=:\\[\\]@]*"

        private const val PATH = "[a-zA-Z0-9\\-._~%!\$&'()*+,;=:@/]*"

        private const val QUERY = "[a-zA-Z0-9\\-._~%!\$&'()*+,;=:@/?]*"

        private const val FRAGMENT = "[a-zA-Z0-9\\-._~%!\$&'()*+,;=:@/?]*"

        // This regular expression matches more than allowed by the generic URI syntax. So we might end up linkifying

        // text that is not a proper URI. We leave apps actually handling the URI when the user clicks on such a link

        // to deal with this case.

        private val PATTERN = Pattern.compile("$SCHEME:(?://$AUTHORITY)?(?:$PATH)?(?:\\?$QUERY)?(?:#$FRAGMENT)?")

    }

}

object UriMatcher {

    private val SUPPORTED_URIS = run {

        val httpUriParser = HttpUriParser()

        val genericUriParser = GenericUriParser()

        mapOf(

            "http:" to httpUriParser,

            "https:" to httpUriParser,

            "rtsp:" to httpUriParser

            "mailto:" to genericUriParser,

            "matrix:" to genericUriParser,

            "rtsp:" to httpUriParser,

            "xmpp:" to genericUriParser,

        )

    }

package com.fsck.k9.message.html

import com.google.common.truth.Truth.assertThat

import kotlin.test.assertNotNull

import org.junit.Test

class GenericUriParserTest {

    private val parser = GenericUriParser()

    @Test

    fun `mailto URIs`() {

        // Examples from RFC 6068

        assertUriValid("mailto:chris@example.com")

        assertUriValid("mailto:infobot@example.com?subject=current-issue")

        assertUriValid("mailto:infobot@example.com?body=send%20current-issue")

        assertUriValid("mailto:infobot@example.com?body=send%20current-issue%0D%0Asend%20index")

        assertUriValid("mailto:list@example.org?In-Reply-To=%3C3469A91.D10AF4C@example.com%3E")

        assertUriValid("mailto:majordomo@example.com?body=subscribe%20bamboo-l")

        assertUriValid("mailto:joe@example.com?cc=bob@example.com&body=hello")

        assertUriValid("mailto:gorby%25kremvax@example.com")

        assertUriValid("mailto:unlikely%3Faddress@example.com?blat=foop")

        assertUriValid("mailto:%22not%40me%22@example.org")

        assertUriValid("mailto:%22oh%5C%5Cno%22@example.org")

        assertUriValid("mailto:%22%5C%5C%5C%22it's%5C%20ugly%5C%5C%5C%22%22@example.org")

        assertUriValid("mailto:user@example.org?subject=caf%C3%A9")

        assertUriValid("mailto:user@example.org?subject=%3D%3Futf-8%3FQ%3Fcaf%3DC3%3DA9%3F%3D")

        assertUriValid("mailto:user@example.org?subject=%3D%3Fiso-8859-1%3FQ%3Fcaf%3DE9%3F%3D")

        assertUriValid("mailto:user@example.org?subject=caf%C3%A9&body=caf%C3%A9")

        assertUriValid("mailto:user@%E7%B4%8D%E8%B1%86.example.org?subject=Test&body=NATTO")

    }

    @Test

    fun `XMPP URIs`() {

        // Examples from RFC 5122

        assertUriValid("xmpp:node@example.com")

        assertUriValid("xmpp://guest@example.com")

        assertUriValid("xmpp://guest@example.com/support@example.com?message")

        assertUriValid("xmpp:support@example.com?message")

        assertUriValid("xmpp:example-node@example.com/some-resource")

        assertUriValid("xmpp:example.com")

        assertUriValid("xmpp:example-node@example.com?message")

        assertUriValid("xmpp:example-node@example.com?message;subject=Hello%20World")

        assertUriValid("xmpp:nasty!%23\$%25()*+,-.;=%3F%5B%5C%5D%5E_%60%7B%7C%7D~node@example.com")

        assertUriValid("xmpp:node@example.com/repulsive%20!%23%22\$%25&'()*+,-.%2F:;%3C=%3E%3F%40%5B%5C%5D%5E_%60%7B%7C%7D~resource")

        assertUriValid("xmpp:ji%C5%99i@%C4%8Dechy.example/v%20Praze")

    }

    @Test

    fun `matrix URIs`() {

        // Examples from MSC 2312

        assertUriValid("matrix:r/someroom:example.org")

        assertUriValid("matrix:u/me:example.org")

        assertUriValid("matrix:r/someroom:example.org/e/Arbitrary_Event_Id")

        assertUriValid("matrix:u/her:example.org")

        assertUriValid("matrix:u/her:example.org?action=chat")

        assertUriValid("matrix:roomid/rid:example.org")

        assertUriValid("matrix:r/us:example.org")

        assertUriValid("matrix:roomid/rid:example.org?action=join&via=example2.org")

        assertUriValid("matrix:r/us:example.org?action=join")

        assertUriValid("matrix:r/us:example.org/e/lol823y4bcp3qo4")

        assertUriValid("matrix:roomid/rid:example.org/event/lol823y4bcp3qo4?via=example2.org")

    }

    private fun assertUriValid(input: String) {

        val result = parser.parseUri(input, 0)

        assertNotNull(result) { uriMatch ->

            assertThat(uriMatch.uri).isEqualTo(input)

        }

    }

}