CasperSecurity
<?php declare(strict_types=1);
namespace PhpParser\Lexer;
use PhpParser\Error;
use PhpParser\ErrorHandler;
use PhpParser\Lexer;
use PhpParser\Lexer\TokenEmulator\AttributeEmulator;
use PhpParser\Lexer\TokenEmulator\EnumTokenEmulator;
use PhpParser\Lexer\TokenEmulator\CoaleseEqualTokenEmulator;
use PhpParser\Lexer\TokenEmulator\FlexibleDocStringEmulator;
use PhpParser\Lexer\TokenEmulator\FnTokenEmulator;
use PhpParser\Lexer\TokenEmulator\MatchTokenEmulator;
use PhpParser\Lexer\TokenEmulator\NullsafeTokenEmulator;
use PhpParser\Lexer\TokenEmulator\NumericLiteralSeparatorEmulator;
use PhpParser\Lexer\TokenEmulator\ReverseEmulator;
use PhpParser\Lexer\TokenEmulator\TokenEmulator;
class Emulative extends Lexer
{
const PHP_7_3 = '7.3dev';
const PHP_7_4 = '7.4dev';
const PHP_8_0 = '8.0dev';
const PHP_8_1 = '8.1dev';
/** @var mixed[] Patches used to reverse changes introduced in the code */
private $patches = [];
/** @var TokenEmulator[] */
private $emulators = [];
/** @var string */
private $targetPhpVersion;
/**
* @param mixed[] $options Lexer options. In addition to the usual options,
* accepts a 'phpVersion' string that specifies the
* version to emulated. Defaults to newest supported.
*/
public function __construct(array $options = [])
{
$this->targetPhpVersion = $options['phpVersion'] ?? Emulative::PHP_8_1;
unset($options['phpVersion']);
parent::__construct($options);
$emulators = [
new FlexibleDocStringEmulator(),
new FnTokenEmulator(),
new MatchTokenEmulator(),
new CoaleseEqualTokenEmulator(),
new NumericLiteralSeparatorEmulator(),
new NullsafeTokenEmulator(),
new AttributeEmulator(),
new EnumTokenEmulator(),
];
// Collect emulators that are relevant for the PHP version we're running
// and the PHP version we're targeting for emulation.
foreach ($emulators as $emulator) {
$emulatorPhpVersion = $emulator->getPhpVersion();
if ($this->isForwardEmulationNeeded($emulatorPhpVersion)) {
$this->emulators[] = $emulator;
} else if ($this->isReverseEmulationNeeded($emulatorPhpVersion)) {
$this->emulators[] = new ReverseEmulator($emulator);
}
}
}
public function startLexing(string $code, ErrorHandler $errorHandler = null) {
$emulators = array_filter($this->emulators, function($emulator) use($code) {
return $emulator->isEmulationNeeded($code);
});
if (empty($emulators)) {
// Nothing to emulate, yay
parent::startLexing($code, $errorHandler);
return;
}
$this->patches = [];
foreach ($emulators as $emulator) {
$code = $emulator->preprocessCode($code, $this->patches);
}
$collector = new ErrorHandler\Collecting();
parent::startLexing($code, $collector);
$this->sortPatches();
$this->fixupTokens();
$errors = $collector->getErrors();
if (!empty($errors)) {
$this->fixupErrors($errors);
foreach ($errors as $error) {
$errorHandler->handleError($error);
}
}
foreach ($emulators as $emulator) {
$this->tokens = $emulator->emulate($code, $this->tokens);
}
}
private function isForwardEmulationNeeded(string $emulatorPhpVersion): bool {
return version_compare(\PHP_VERSION, $emulatorPhpVersion, '<')
&& version_compare($this->targetPhpVersion, $emulatorPhpVersion, '>=');
}
private function isReverseEmulationNeeded(string $emulatorPhpVersion): bool {
return version_compare(\PHP_VERSION, $emulatorPhpVersion, '>=')
&& version_compare($this->targetPhpVersion, $emulatorPhpVersion, '<');
}
private function sortPatches()
{
// Patches may be contributed by different emulators.
// Make sure they are sorted by increasing patch position.
usort($this->patches, function($p1, $p2) {
return $p1[0] <=> $p2[0];
});
}
private function fixupTokens()
{
if (\count($this->patches) === 0) {
return;
}
// 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($token)) {
if ($patchPos === $pos) {
// Only support replacement for string tokens.
assert($patchType === 'replace');
$this->tokens[$i] = $patchText;
// Fetch the next patch
$patchIdx++;
if ($patchIdx >= \count($this->patches)) {
// No more patches, we're done
return;
}
list($patchPos, $patchType, $patchText) = $this->patches[$patchIdx];
}
$pos += \strlen($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 += $patchTextLen;
} else if ($patchType === 'replace') {
// Replace inside the token string
$this->tokens[$i][1] = substr_replace(
$token[1], $patchText, $patchPos - $pos + $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 if ($patchType === 'remove') {
$posDelta -= strlen($patchText);
$lineDelta -= substr_count($patchText, "\n");
}
}
$attrs['startFilePos'] += $posDelta;
$attrs['endFilePos'] += $posDelta;
$attrs['startLine'] += $lineDelta;
$attrs['endLine'] += $lineDelta;
$error->setAttributes($attrs);
}
}
}