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<?php
declare(strict_types=1);
/*
* This file is part of the league/commonmark package.
*
* (c) Colin O'Dell <colinodell@gmail.com>
*
* Original code based on the CommonMark JS reference parser (https://bitly.com/commonmark-js)
* - (c) John MacFarlane
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace League\CommonMark\Reference;
use League\CommonMark\Parser\Cursor;
use League\CommonMark\Util\LinkParserHelper;
final class ReferenceParser
{
// Looking for the start of a definition, i.e. `[`
private const START_DEFINITION = 0;
// Looking for and parsing the label, i.e. `[foo]` within `[foo]`
private const LABEL = 1;
// Parsing the destination, i.e. `/url` in `[foo]: /url`
private const DESTINATION = 2;
// Looking for the start of a title, i.e. the first `"` in `[foo]: /url "title"`
private const START_TITLE = 3;
// Parsing the content of the title, i.e. `title` in `[foo]: /url "title"`
private const TITLE = 4;
// End state, no matter what kind of lines we add, they won't be references
private const PARAGRAPH = 5;
/** @psalm-readonly-allow-private-mutation */
private string $paragraph = '';
/**
* @var array<int, ReferenceInterface>
*
* @psalm-readonly-allow-private-mutation
*/
private array $references = [];
/** @psalm-readonly-allow-private-mutation */
private int $state = self::START_DEFINITION;
/** @psalm-readonly-allow-private-mutation */
private ?string $label = null;
/** @psalm-readonly-allow-private-mutation */
private ?string $destination = null;
/**
* @var string string
*
* @psalm-readonly-allow-private-mutation
*/
private string $title = '';
/** @psalm-readonly-allow-private-mutation */
private ?string $titleDelimiter = null;
/** @psalm-readonly-allow-private-mutation */
private bool $referenceValid = false;
public function getParagraphContent(): string
{
return $this->paragraph;
}
/**
* @return ReferenceInterface[]
*/
public function getReferences(): iterable
{
$this->finishReference();
return $this->references;
}
public function hasReferences(): bool
{
return $this->references !== [];
}
public function parse(string $line): void
{
if ($this->paragraph !== '') {
$this->paragraph .= "\n";
}
$this->paragraph .= $line;
$cursor = new Cursor($line);
while (! $cursor->isAtEnd()) {
$result = false;
switch ($this->state) {
case self::PARAGRAPH:
// We're in a paragraph now. Link reference definitions can only appear at the beginning, so once
// we're in a paragraph, there's no going back.
return;
case self::START_DEFINITION:
$result = $this->parseStartDefinition($cursor);
break;
case self::LABEL:
$result = $this->parseLabel($cursor);
break;
case self::DESTINATION:
$result = $this->parseDestination($cursor);
break;
case self::START_TITLE:
$result = $this->parseStartTitle($cursor);
break;
case self::TITLE:
$result = $this->parseTitle($cursor);
break;
default:
// this should never happen
break;
}
if (! $result) {
$this->state = self::PARAGRAPH;
return;
}
}
}
private function parseStartDefinition(Cursor $cursor): bool
{
$cursor->advanceToNextNonSpaceOrTab();
if ($cursor->isAtEnd() || $cursor->getCurrentCharacter() !== '[') {
return false;
}
$this->state = self::LABEL;
$this->label = '';
$cursor->advance();
if ($cursor->isAtEnd()) {
$this->label .= "\n";
}
return true;
}
private function parseLabel(Cursor $cursor): bool
{
$cursor->advanceToNextNonSpaceOrTab();
$partialLabel = LinkParserHelper::parsePartialLinkLabel($cursor);
if ($partialLabel === null) {
return false;
}
\assert($this->label !== null);
$this->label .= $partialLabel;
if ($cursor->isAtEnd()) {
// label might continue on next line
$this->label .= "\n";
return true;
}
if ($cursor->getCurrentCharacter() !== ']') {
return false;
}
$cursor->advance();
// end of label
if ($cursor->getCurrentCharacter() !== ':') {
return false;
}
$cursor->advance();
// spec: A link label can have at most 999 characters inside the square brackets
if (\mb_strlen($this->label, 'UTF-8') > 999) {
return false;
}
// spec: A link label must contain at least one non-whitespace character
if (\trim($this->label) === '') {
return false;
}
$cursor->advanceToNextNonSpaceOrTab();
$this->state = self::DESTINATION;
return true;
}
private function parseDestination(Cursor $cursor): bool
{
$cursor->advanceToNextNonSpaceOrTab();
$destination = LinkParserHelper::parseLinkDestination($cursor);
if ($destination === null) {
return false;
}
$this->destination = $destination;
$advanced = $cursor->advanceToNextNonSpaceOrTab();
if ($cursor->isAtEnd()) {
// Destination was at end of line, so this is a valid reference for sure (and maybe a title).
// If not at end of line, wait for title to be valid first.
$this->referenceValid = true;
$this->paragraph = '';
} elseif ($advanced === 0) {
// spec: The title must be separated from the link destination by whitespace
return false;
}
$this->state = self::START_TITLE;
return true;
}
private function parseStartTitle(Cursor $cursor): bool
{
$cursor->advanceToNextNonSpaceOrTab();
if ($cursor->isAtEnd()) {
$this->state = self::START_DEFINITION;
return true;
}
$this->titleDelimiter = null;
switch ($c = $cursor->getCurrentCharacter()) {
case '"':
case "'":
$this->titleDelimiter = $c;
break;
case '(':
$this->titleDelimiter = ')';
break;
default:
// no title delimter found
break;
}
if ($this->titleDelimiter !== null) {
$this->state = self::TITLE;
$cursor->advance();
if ($cursor->isAtEnd()) {
$this->title .= "\n";
}
} else {
$this->finishReference();
// There might be another reference instead, try that for the same character.
$this->state = self::START_DEFINITION;
}
return true;
}
private function parseTitle(Cursor $cursor): bool
{
\assert($this->titleDelimiter !== null);
$title = LinkParserHelper::parsePartialLinkTitle($cursor, $this->titleDelimiter);
if ($title === null) {
// Invalid title, stop
return false;
}
// Did we find the end delimiter?
$endDelimiterFound = false;
if (\substr($title, -1) === $this->titleDelimiter) {
$endDelimiterFound = true;
// Chop it off
$title = \substr($title, 0, -1);
}
$this->title .= $title;
if (! $endDelimiterFound && $cursor->isAtEnd()) {
// Title still going, continue on next line
$this->title .= "\n";
return true;
}
// We either hit the end delimiter or some extra whitespace
$cursor->advanceToNextNonSpaceOrTab();
if (! $cursor->isAtEnd()) {
// spec: No further non-whitespace characters may occur on the line.
return false;
}
$this->referenceValid = true;
$this->finishReference();
$this->paragraph = '';
// See if there's another definition
$this->state = self::START_DEFINITION;
return true;
}
private function finishReference(): void
{
if (! $this->referenceValid) {
return;
}
/** @psalm-suppress PossiblyNullArgument -- these can't possibly be null if we're in this state */
$this->references[] = new Reference($this->label, $this->destination, $this->title);
$this->label = null;
$this->referenceValid = false;
$this->destination = null;
$this->title = '';
$this->titleDelimiter = null;
}
}
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