Chris@13: <?php declare(strict_types=1);
Chris@0: 
Chris@0: namespace PhpParser\Lexer;
Chris@0: 
Chris@17: use PhpParser\Error;
Chris@17: use PhpParser\ErrorHandler;
Chris@17: use PhpParser\Parser;
Chris@17: 
Chris@0: class Emulative extends \PhpParser\Lexer
Chris@0: {
Chris@17:     const PHP_7_3 = '7.3.0dev';
Chris@17:     const PHP_7_4 = '7.4.0dev';
Chris@17: 
Chris@17:     const FLEXIBLE_DOC_STRING_REGEX = <<<'REGEX'
Chris@17: /<<<[ \t]*(['"]?)([a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*)\1\r?\n
Chris@17: (?:.*\r?\n)*?
Chris@17: (?<indentation>\h*)\2(?![a-zA-Z_\x80-\xff])(?<separator>(?:;?[\r\n])?)/x
Chris@17: REGEX;
Chris@17: 
Chris@17:     const T_COALESCE_EQUAL = 1007;
Chris@17: 
Chris@17:     /**
Chris@17:      * @var mixed[] Patches used to reverse changes introduced in the code
Chris@17:      */
Chris@17:     private $patches = [];
Chris@17: 
Chris@17:     /**
Chris@17:      * @param mixed[] $options
Chris@17:      */
Chris@17:     public function __construct(array $options = [])
Chris@17:     {
Chris@17:         parent::__construct($options);
Chris@17: 
Chris@17:         // add emulated tokens here
Chris@17:         $this->tokenMap[self::T_COALESCE_EQUAL] = Parser\Tokens::T_COALESCE_EQUAL;
Chris@17:     }
Chris@17: 
Chris@17:     public function startLexing(string $code, ErrorHandler $errorHandler = null) {
Chris@17:         $this->patches = [];
Chris@17: 
Chris@17:         if ($this->isEmulationNeeded($code) === false) {
Chris@17:             // Nothing to emulate, yay
Chris@17:             parent::startLexing($code, $errorHandler);
Chris@17:             return;
Chris@17:         }
Chris@17: 
Chris@17:         $collector = new ErrorHandler\Collecting();
Chris@17: 
Chris@17:         // 1. emulation of heredoc and nowdoc new syntax
Chris@17:         $preparedCode = $this->processHeredocNowdoc($code);
Chris@17:         parent::startLexing($preparedCode, $collector);
Chris@17: 
Chris@17:         // 2. emulation of ??= token
Chris@17:         $this->processCoaleseEqual($code);
Chris@17:         $this->fixupTokens();
Chris@17: 
Chris@17:         $errors = $collector->getErrors();
Chris@17:         if (!empty($errors)) {
Chris@17:             $this->fixupErrors($errors);
Chris@17:             foreach ($errors as $error) {
Chris@17:                 $errorHandler->handleError($error);
Chris@17:             }
Chris@17:         }
Chris@17:     }
Chris@17: 
Chris@17:     private function isCoalesceEqualEmulationNeeded(string $code): bool
Chris@17:     {
Chris@17:         // skip version where this works without emulation
Chris@17:         if (version_compare(\PHP_VERSION, self::PHP_7_4, '>=')) {
Chris@17:             return false;
Chris@17:         }
Chris@17: 
Chris@17:         return strpos($code, '??=') !== false;
Chris@17:     }
Chris@17: 
Chris@17:     private function processCoaleseEqual(string $code)
Chris@17:     {
Chris@17:         if ($this->isCoalesceEqualEmulationNeeded($code) === false) {
Chris@17:             return;
Chris@17:         }
Chris@17: 
Chris@17:         // We need to manually iterate and manage a count because we'll change
Chris@17:         // the tokens array on the way
Chris@17:         $line = 1;
Chris@17:         for ($i = 0, $c = count($this->tokens); $i < $c; ++$i) {
Chris@17:             if (isset($this->tokens[$i + 1])) {
Chris@17:                 if ($this->tokens[$i][0] === T_COALESCE && $this->tokens[$i + 1] === '=') {
Chris@17:                     array_splice($this->tokens, $i, 2, [
Chris@17:                         [self::T_COALESCE_EQUAL, '??=', $line]
Chris@17:                     ]);
Chris@17:                     $c--;
Chris@17:                     continue;
Chris@17:                 }
Chris@17:             }
Chris@17:             if (\is_array($this->tokens[$i])) {
Chris@17:                 $line += substr_count($this->tokens[$i][1], "\n");
Chris@17:             }
Chris@17:         }
Chris@17:     }
Chris@17: 
Chris@17:     private function isHeredocNowdocEmulationNeeded(string $code): bool
Chris@17:     {
Chris@17:         // skip version where this works without emulation
Chris@17:         if (version_compare(\PHP_VERSION, self::PHP_7_3, '>=')) {
Chris@17:             return false;
Chris@17:         }
Chris@17: 
Chris@17:         return strpos($code, '<<<') !== false;
Chris@17:     }
Chris@17: 
Chris@17:     private function processHeredocNowdoc(string $code): string
Chris@17:     {
Chris@17:         if ($this->isHeredocNowdocEmulationNeeded($code) === false) {
Chris@17:             return $code;
Chris@17:         }
Chris@17: 
Chris@17:         if (!preg_match_all(self::FLEXIBLE_DOC_STRING_REGEX, $code, $matches, PREG_SET_ORDER|PREG_OFFSET_CAPTURE)) {
Chris@17:             // No heredoc/nowdoc found
Chris@17:             return $code;
Chris@17:         }
Chris@17: 
Chris@17:         // Keep track of how much we need to adjust string offsets due to the modifications we
Chris@17:         // already made
Chris@17:         $posDelta = 0;
Chris@17:         foreach ($matches as $match) {
Chris@17:             $indentation = $match['indentation'][0];
Chris@17:             $indentationStart = $match['indentation'][1];
Chris@17: 
Chris@17:             $separator = $match['separator'][0];
Chris@17:             $separatorStart = $match['separator'][1];
Chris@17: 
Chris@17:             if ($indentation === '' && $separator !== '') {
Chris@17:                 // Ordinary heredoc/nowdoc
Chris@17:                 continue;
Chris@17:             }
Chris@17: 
Chris@17:             if ($indentation !== '') {
Chris@17:                 // Remove indentation
Chris@17:                 $indentationLen = strlen($indentation);
Chris@17:                 $code = substr_replace($code, '', $indentationStart + $posDelta, $indentationLen);
Chris@17:                 $this->patches[] = [$indentationStart + $posDelta, 'add', $indentation];
Chris@17:                 $posDelta -= $indentationLen;
Chris@17:             }
Chris@17: 
Chris@17:             if ($separator === '') {
Chris@17:                 // Insert newline as separator
Chris@17:                 $code = substr_replace($code, "\n", $separatorStart + $posDelta, 0);
Chris@17:                 $this->patches[] = [$separatorStart + $posDelta, 'remove', "\n"];
Chris@17:                 $posDelta += 1;
Chris@17:             }
Chris@17:         }
Chris@17: 
Chris@17:         return $code;
Chris@17:     }
Chris@17: 
Chris@17:     private function isEmulationNeeded(string $code): bool
Chris@17:     {
Chris@17:         if ($this->isHeredocNowdocEmulationNeeded($code)) {
Chris@17:             return true;
Chris@17:         }
Chris@17: 
Chris@17:         if ($this->isCoalesceEqualEmulationNeeded($code)) {
Chris@17:             return true;
Chris@17:         }
Chris@17: 
Chris@17:         return false;
Chris@17:     }
Chris@17: 
Chris@17:     private function fixupTokens()
Chris@17:     {
Chris@17:         if (\count($this->patches) === 0) {
Chris@17:             return;
Chris@17:         }
Chris@17: 
Chris@17:         // Load first patch
Chris@17:         $patchIdx = 0;
Chris@17: 
Chris@17:         list($patchPos, $patchType, $patchText) = $this->patches[$patchIdx];
Chris@17: 
Chris@17:         // We use a manual loop over the tokens, because we modify the array on the fly
Chris@17:         $pos = 0;
Chris@17:         for ($i = 0, $c = \count($this->tokens); $i < $c; $i++) {
Chris@17:             $token = $this->tokens[$i];
Chris@17:             if (\is_string($token)) {
Chris@17:                 // We assume that patches don't apply to string tokens
Chris@17:                 $pos += \strlen($token);
Chris@17:                 continue;
Chris@17:             }
Chris@17: 
Chris@17:             $len = \strlen($token[1]);
Chris@17:             $posDelta = 0;
Chris@17:             while ($patchPos >= $pos && $patchPos < $pos + $len) {
Chris@17:                 $patchTextLen = \strlen($patchText);
Chris@17:                 if ($patchType === 'remove') {
Chris@17:                     if ($patchPos === $pos && $patchTextLen === $len) {
Chris@17:                         // Remove token entirely
Chris@17:                         array_splice($this->tokens, $i, 1, []);
Chris@17:                         $i--;
Chris@17:                         $c--;
Chris@17:                     } else {
Chris@17:                         // Remove from token string
Chris@17:                         $this->tokens[$i][1] = substr_replace(
Chris@17:                             $token[1], '', $patchPos - $pos + $posDelta, $patchTextLen
Chris@17:                         );
Chris@17:                         $posDelta -= $patchTextLen;
Chris@17:                     }
Chris@17:                 } elseif ($patchType === 'add') {
Chris@17:                     // Insert into the token string
Chris@17:                     $this->tokens[$i][1] = substr_replace(
Chris@17:                         $token[1], $patchText, $patchPos - $pos + $posDelta, 0
Chris@17:                     );
Chris@17:                     $posDelta += $patchTextLen;
Chris@17:                 } else {
Chris@17:                     assert(false);
Chris@17:                 }
Chris@17: 
Chris@17:                 // Fetch the next patch
Chris@17:                 $patchIdx++;
Chris@17:                 if ($patchIdx >= \count($this->patches)) {
Chris@17:                     // No more patches, we're done
Chris@17:                     return;
Chris@17:                 }
Chris@17: 
Chris@17:                 list($patchPos, $patchType, $patchText) = $this->patches[$patchIdx];
Chris@17: 
Chris@17:                 // Multiple patches may apply to the same token. Reload the current one to check
Chris@17:                 // If the new patch applies
Chris@17:                 $token = $this->tokens[$i];
Chris@17:             }
Chris@17: 
Chris@17:             $pos += $len;
Chris@17:         }
Chris@17: 
Chris@17:         // A patch did not apply
Chris@17:         assert(false);
Chris@17:     }
Chris@17: 
Chris@17:     /**
Chris@17:      * Fixup line and position information in errors.
Chris@17:      *
Chris@17:      * @param Error[] $errors
Chris@17:      */
Chris@17:     private function fixupErrors(array $errors) {
Chris@17:         foreach ($errors as $error) {
Chris@17:             $attrs = $error->getAttributes();
Chris@17: 
Chris@17:             $posDelta = 0;
Chris@17:             $lineDelta = 0;
Chris@17:             foreach ($this->patches as $patch) {
Chris@17:                 list($patchPos, $patchType, $patchText) = $patch;
Chris@17:                 if ($patchPos >= $attrs['startFilePos']) {
Chris@17:                     // No longer relevant
Chris@17:                     break;
Chris@17:                 }
Chris@17: 
Chris@17:                 if ($patchType === 'add') {
Chris@17:                     $posDelta += strlen($patchText);
Chris@17:                     $lineDelta += substr_count($patchText, "\n");
Chris@17:                 } else {
Chris@17:                     $posDelta -= strlen($patchText);
Chris@17:                     $lineDelta -= substr_count($patchText, "\n");
Chris@17:                 }
Chris@17:             }
Chris@17: 
Chris@17:             $attrs['startFilePos'] += $posDelta;
Chris@17:             $attrs['endFilePos'] += $posDelta;
Chris@17:             $attrs['startLine'] += $lineDelta;
Chris@17:             $attrs['endLine'] += $lineDelta;
Chris@17:             $error->setAttributes($attrs);
Chris@17:         }
Chris@17:     }
Chris@0: }