namespace PhpParser\Lexer;
+use PhpParser\Error;
+use PhpParser\ErrorHandler;
+
class Emulative extends \PhpParser\Lexer
{
- /* No features requiring emulation have been added in PHP > 7.0 */
-}
+ const PHP_7_3 = '7.3.0dev';
+
+ /**
+ * @var array Patches used to reverse changes introduced in the code
+ */
+ private $patches;
+
+ public function startLexing(string $code, ErrorHandler $errorHandler = null) {
+ $this->patches = [];
+ $preparedCode = $this->prepareCode($code);
+ if (null === $preparedCode) {
+ // Nothing to emulate, yay
+ parent::startLexing($code, $errorHandler);
+ return;
+ }
+
+ $collector = new ErrorHandler\Collecting();
+ parent::startLexing($preparedCode, $collector);
+ $this->fixupTokens();
+
+ $errors = $collector->getErrors();
+ if (!empty($errors)) {
+ $this->fixupErrors($errors);
+ foreach ($errors as $error) {
+ $errorHandler->handleError($error);
+ }
+ }
+ }
+
+ /**
+ * Prepares code for emulation. If nothing has to be emulated null is returned.
+ *
+ * @param string $code
+ * @return null|string
+ */
+ private function prepareCode(string $code) {
+ if (version_compare(\PHP_VERSION, self::PHP_7_3, '>=')) {
+ return null;
+ }
+
+ if (strpos($code, '<<<') === false) {
+ // Definitely doesn't contain heredoc/nowdoc
+ return null;
+ }
+
+ $flexibleDocStringRegex = <<<'REGEX'
+/<<<[ \t]*(['"]?)([a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*)\1\r?\n
+(?:.*\r?\n)*?
+(?<indentation>\h*)\2(?![a-zA-Z_\x80-\xff])(?<separator>(?:;?[\r\n])?)/x
+REGEX;
+ if (!preg_match_all($flexibleDocStringRegex, $code, $matches, PREG_SET_ORDER|PREG_OFFSET_CAPTURE)) {
+ // No heredoc/nowdoc found
+ return null;
+ }
+
+ // Keep track of how much we need to adjust string offsets due to the modifications we
+ // already made
+ $posDelta = 0;
+ foreach ($matches as $match) {
+ $indentation = $match['indentation'][0];
+ $indentationStart = $match['indentation'][1];
+
+ $separator = $match['separator'][0];
+ $separatorStart = $match['separator'][1];
+
+ if ($indentation === '' && $separator !== '') {
+ // Ordinary heredoc/nowdoc
+ continue;
+ }
+
+ if ($indentation !== '') {
+ // Remove indentation
+ $indentationLen = strlen($indentation);
+ $code = substr_replace($code, '', $indentationStart + $posDelta, $indentationLen);
+ $this->patches[] = [$indentationStart + $posDelta, 'add', $indentation];
+ $posDelta -= $indentationLen;
+ }
+
+ if ($separator === '') {
+ // Insert newline as separator
+ $code = substr_replace($code, "\n", $separatorStart + $posDelta, 0);
+ $this->patches[] = [$separatorStart + $posDelta, 'remove', "\n"];
+ $posDelta += 1;
+ }
+ }
+
+ if (empty($this->patches)) {
+ // We did not end up emulating anything
+ return null;
+ }
+
+ return $code;
+ }
+
+ private function fixupTokens() {
+ assert(count($this->patches) > 0);
+
+ // Load first patch
+ $patchIdx = 0;
+ list($patchPos, $patchType, $patchText) = $this->patches[$patchIdx];
+
+ // We use a manual loop over the tokens, because we modify the array on the fly
+ $pos = 0;
+ for ($i = 0, $c = \count($this->tokens); $i < $c; $i++) {
+ $token = $this->tokens[$i];
+ if (\is_string($token)) {
+ // We assume that patches don't apply to string tokens
+ $pos += \strlen($token);
+ continue;
+ }
+
+ $len = \strlen($token[1]);
+ $posDelta = 0;
+ while ($patchPos >= $pos && $patchPos < $pos + $len) {
+ $patchTextLen = \strlen($patchText);
+ if ($patchType === 'remove') {
+ if ($patchPos === $pos && $patchTextLen === $len) {
+ // Remove token entirely
+ array_splice($this->tokens, $i, 1, []);
+ $i--;
+ $c--;
+ } else {
+ // Remove from token string
+ $this->tokens[$i][1] = substr_replace(
+ $token[1], '', $patchPos - $pos + $posDelta, $patchTextLen
+ );
+ $posDelta -= $patchTextLen;
+ }
+ } elseif ($patchType === 'add') {
+ // Insert into the token string
+ $this->tokens[$i][1] = substr_replace(
+ $token[1], $patchText, $patchPos - $pos + $posDelta, 0
+ );
+ $posDelta += $patchTextLen;
+ } else {
+ assert(false);
+ }
+
+ // Fetch the next patch
+ $patchIdx++;
+ if ($patchIdx >= \count($this->patches)) {
+ // No more patches, we're done
+ return;
+ }
+
+ list($patchPos, $patchType, $patchText) = $this->patches[$patchIdx];
+
+ // Multiple patches may apply to the same token. Reload the current one to check
+ // If the new patch applies
+ $token = $this->tokens[$i];
+ }
+
+ $pos += $len;
+ }
+
+ // A patch did not apply
+ assert(false);
+ }
+
+ /**
+ * Fixup line and position information in errors.
+ *
+ * @param Error[] $errors
+ */
+ private function fixupErrors(array $errors) {
+ foreach ($errors as $error) {
+ $attrs = $error->getAttributes();
+
+ $posDelta = 0;
+ $lineDelta = 0;
+ foreach ($this->patches as $patch) {
+ list($patchPos, $patchType, $patchText) = $patch;
+ if ($patchPos >= $attrs['startFilePos']) {
+ // No longer relevant
+ break;
+ }
+
+ if ($patchType === 'add') {
+ $posDelta += strlen($patchText);
+ $lineDelta += substr_count($patchText, "\n");
+ } else {
+ $posDelta -= strlen($patchText);
+ $lineDelta -= substr_count($patchText, "\n");
+ }
+ }
+
+ $attrs['startFilePos'] += $posDelta;
+ $attrs['endFilePos'] += $posDelta;
+ $attrs['startLine'] += $lineDelta;
+ $attrs['endLine'] += $lineDelta;
+ $error->setAttributes($attrs);
+ }
+ }
+}
\ No newline at end of file
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