<?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
*
* Additional code based on commonmark-java (https://github.com/commonmark/commonmark-java)
* - (c) Atlassian Pty Ltd
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace League\CommonMark\Parser;
use League\CommonMark\Environment\EnvironmentInterface;
use League\CommonMark\Event\DocumentParsedEvent;
use League\CommonMark\Event\DocumentPreParsedEvent;
use League\CommonMark\Exception\CommonMarkException;
use League\CommonMark\Input\MarkdownInput;
use League\CommonMark\Node\Block\Document;
use League\CommonMark\Node\Block\Paragraph;
use League\CommonMark\Parser\Block\BlockContinueParserInterface;
use League\CommonMark\Parser\Block\BlockContinueParserWithInlinesInterface;
use League\CommonMark\Parser\Block\BlockStart;
use League\CommonMark\Parser\Block\BlockStartParserInterface;
use League\CommonMark\Parser\Block\DocumentBlockParser;
use League\CommonMark\Parser\Block\ParagraphParser;
use League\CommonMark\Reference\ReferenceInterface;
use League\CommonMark\Reference\ReferenceMap;
final class MarkdownParser implements MarkdownParserInterface
{
/** @psalm-readonly */
private EnvironmentInterface $environment;
/** @psalm-readonly-allow-private-mutation */
private int $maxNestingLevel;
/** @psalm-readonly-allow-private-mutation */
private ReferenceMap $referenceMap;
/** @psalm-readonly-allow-private-mutation */
private int $lineNumber = 0;
/** @psalm-readonly-allow-private-mutation */
private Cursor $cursor;
/**
* @var array<int, BlockContinueParserInterface>
*
* @psalm-readonly-allow-private-mutation
*/
private array $activeBlockParsers = [];
/**
* @var array<int, BlockContinueParserWithInlinesInterface>
*
* @psalm-readonly-allow-private-mutation
*/
private array $closedBlockParsers = [];
public function __construct(EnvironmentInterface $environment)
{
$this->environment = $environment;
}
private function initialize(): void
{
$this->referenceMap = new ReferenceMap();
$this->lineNumber = 0;
$this->activeBlockParsers = [];
$this->closedBlockParsers = [];
$this->maxNestingLevel = $this->environment->getConfiguration()->get('max_nesting_level');
}
/**
* @throws CommonMarkException
*/
public function parse(string $input): Document
{
$this->initialize();
$documentParser = new DocumentBlockParser($this->referenceMap);
$this->activateBlockParser($documentParser);
$preParsedEvent = new DocumentPreParsedEvent($documentParser->getBlock(), new MarkdownInput($input));
$this->environment->dispatch($preParsedEvent);
$markdownInput = $preParsedEvent->getMarkdown();
foreach ($markdownInput->getLines() as $lineNumber => $line) {
$this->lineNumber = $lineNumber;
$this->parseLine($line);
}
// finalizeAndProcess
$this->closeBlockParsers(\count($this->activeBlockParsers), $this->lineNumber);
$this->processInlines();
$this->environment->dispatch(new DocumentParsedEvent($documentParser->getBlock()));
return $documentParser->getBlock();
}
/**
* Analyze a line of text and update the document appropriately. We parse markdown text by calling this on each
* line of input, then finalizing the document.
*/
private function parseLine(string $line): void
{
$this->cursor = new Cursor($line);
$matches = $this->parseBlockContinuation();
if ($matches === null) {
return;
}
$unmatchedBlocks = \count($this->activeBlockParsers) - $matches;
$blockParser = $this->activeBlockParsers[$matches - 1];
$startedNewBlock = false;
// Unless last matched container is a code block, try new container starts,
// adding children to the last matched container:
$tryBlockStarts = $blockParser->getBlock() instanceof Paragraph || $blockParser->isContainer();
while ($tryBlockStarts) {
// this is a little performance optimization
if ($this->cursor->isBlank()) {
$this->cursor->advanceToEnd();
break;
}
if ($blockParser->getBlock()->getDepth() >= $this->maxNestingLevel) {
break;
}
$blockStart = $this->findBlockStart($blockParser);
if ($blockStart === null || $blockStart->isAborting()) {
$this->cursor->advanceToNextNonSpaceOrTab();
break;
}
if (($state = $blockStart->getCursorState()) !== null) {
$this->cursor->restoreState($state);
}
$startedNewBlock = true;
// We're starting a new block. If we have any previous blocks that need to be closed, we need to do it now.
if ($unmatchedBlocks > 0) {
$this->closeBlockParsers($unmatchedBlocks, $this->lineNumber - 1);
$unmatchedBlocks = 0;
}
if ($blockStart->isReplaceActiveBlockParser()) {
$this->prepareActiveBlockParserForReplacement();
}
foreach ($blockStart->getBlockParsers() as $newBlockParser) {
$blockParser = $this->addChild($newBlockParser);
$tryBlockStarts = $newBlockParser->isContainer();
}
}
// What remains at the offset is a text line. Add the text to the appropriate block.
// First check for a lazy paragraph continuation:
if (! $startedNewBlock && ! $this->cursor->isBlank() && $this->getActiveBlockParser()->canHaveLazyContinuationLines()) {
$this->getActiveBlockParser()->addLine($this->cursor->getRemainder());
} else {
// finalize any blocks not matched
if ($unmatchedBlocks > 0) {
$this->closeBlockParsers($unmatchedBlocks, $this->lineNumber);
}
if (! $blockParser->isContainer()) {
$this->getActiveBlockParser()->addLine($this->cursor->getRemainder());
} elseif (! $this->cursor->isBlank()) {
$this->addChild(new ParagraphParser());
$this->getActiveBlockParser()->addLine($this->cursor->getRemainder());
}
}
}
private function parseBlockContinuation(): ?int
{
// For each containing block, try to parse the associated line start.
// The document will always match, so we can skip the first block parser and start at 1 matches
$matches = 1;
for ($i = 1; $i < \count($this->activeBlockParsers); $i++) {
$blockParser = $this->activeBlockParsers[$i];
$blockContinue = $blockParser->tryContinue(clone $this->cursor, $this->getActiveBlockParser());
if ($blockContinue === null) {
break;
}
if ($blockContinue->isFinalize()) {
$this->closeBlockParsers(\count($this->activeBlockParsers) - $i, $this->lineNumber);
return null;
}
if (($state = $blockContinue->getCursorState()) !== null) {
$this->cursor->restoreState($state);
}
$matches++;
}
return $matches;
}
private function findBlockStart(BlockContinueParserInterface $lastMatchedBlockParser): ?BlockStart
{
$matchedBlockParser = new MarkdownParserState($this->getActiveBlockParser(), $lastMatchedBlockParser);
foreach ($this->environment->getBlockStartParsers() as $blockStartParser) {
\assert($blockStartParser instanceof BlockStartParserInterface);
if (($result = $blockStartParser->tryStart(clone $this->cursor, $matchedBlockParser)) !== null) {
return $result;
}
}
return null;
}
private function closeBlockParsers(int $count, int $endLineNumber): void
{
for ($i = 0; $i < $count; $i++) {
$blockParser = $this->deactivateBlockParser();
$this->finalize($blockParser, $endLineNumber);
// phpcs:disable SlevomatCodingStandard.ControlStructures.EarlyExit.EarlyExitNotUsed
if ($blockParser instanceof BlockContinueParserWithInlinesInterface) {
// Remember for inline parsing
$this->closedBlockParsers[] = $blockParser;
}
}
}
/**
* Finalize a block. Close it and do any necessary postprocessing, e.g. creating string_content from strings,
* setting the 'tight' or 'loose' status of a list, and parsing the beginnings of paragraphs for reference
* definitions.
*/
private function finalize(BlockContinueParserInterface $blockParser, int $endLineNumber): void
{
if ($blockParser instanceof ParagraphParser) {
$this->updateReferenceMap($blockParser->getReferences());
}
$blockParser->getBlock()->setEndLine($endLineNumber);
$blockParser->closeBlock();
}
/**
* Walk through a block & children recursively, parsing string content into inline content where appropriate.
*/
private function processInlines(): void
{
$p = new InlineParserEngine($this->environment, $this->referenceMap);
foreach ($this->closedBlockParsers as $blockParser) {
$blockParser->parseInlines($p);
}
}
/**
* Add block of type tag as a child of the tip. If the tip can't accept children, close and finalize it and try
* its parent, and so on til we find a block that can accept children.
*/
private function addChild(BlockContinueParserInterface $blockParser): BlockContinueParserInterface
{
$blockParser->getBlock()->setStartLine($this->lineNumber);
while (! $this->getActiveBlockParser()->canContain($blockParser->getBlock())) {
$this->closeBlockParsers(1, $this->lineNumber - 1);
}
$this->getActiveBlockParser()->getBlock()->appendChild($blockParser->getBlock());
$this->activateBlockParser($blockParser);
return $blockParser;
}
private function activateBlockParser(BlockContinueParserInterface $blockParser): void
{
$this->activeBlockParsers[] = $blockParser;
}
/**
* @throws ParserLogicException
*/
private function deactivateBlockParser(): BlockContinueParserInterface
{
$popped = \array_pop($this->activeBlockParsers);
if ($popped === null) {
throw new ParserLogicException('The last block parser should not be deactivated');
}
return $popped;
}
private function prepareActiveBlockParserForReplacement(): void
{
// Note that we don't want to parse inlines or finalize this block, as it's getting replaced.
$old = $this->deactivateBlockParser();
if ($old instanceof ParagraphParser) {
$this->updateReferenceMap($old->getReferences());
}
$old->getBlock()->detach();
}
/**
* @param ReferenceInterface[] $references
*/
private function updateReferenceMap(iterable $references): void
{
foreach ($references as $reference) {
if (! $this->referenceMap->contains($reference->getLabel())) {
$this->referenceMap->add($reference);
}
}
}
/**
* @throws ParserLogicException
*/
public function getActiveBlockParser(): BlockContinueParserInterface
{
$active = \end($this->activeBlockParsers);
if ($active === false) {
throw new ParserLogicException('No active block parsers are available');
}
return $active;
}
}