php-parser/lib/PhpParser/Lexer.php
Nikita Popov c758510a37 Add support for PHP 8.1
With the introduction of intersection types, PHP now lexes the
token '&' either as T_AMPERSAND_(NOT_)FOLLOWED_BY_VAR_OR_VARARG.
This completely breaks parsing of any code containing '&'.

Fix this by canonicalizing to the new token format (unconditionally,
independent of emulation) and adjusting the parser to use the two
new tokens.

This doesn't add actual support for intersection types yet.
2021-07-09 16:52:58 +02:00

559 lines
23 KiB
PHP

<?php declare(strict_types=1);
namespace PhpParser;
use PhpParser\Parser\Tokens;
class Lexer
{
protected $code;
protected $tokens;
protected $pos;
protected $line;
protected $filePos;
protected $prevCloseTagHasNewline;
protected $tokenMap;
protected $dropTokens;
protected $identifierTokens;
private $attributeStartLineUsed;
private $attributeEndLineUsed;
private $attributeStartTokenPosUsed;
private $attributeEndTokenPosUsed;
private $attributeStartFilePosUsed;
private $attributeEndFilePosUsed;
private $attributeCommentsUsed;
/**
* Creates a Lexer.
*
* @param array $options Options array. Currently only the 'usedAttributes' option is supported,
* which is an array of attributes to add to the AST nodes. Possible
* attributes are: 'comments', 'startLine', 'endLine', 'startTokenPos',
* 'endTokenPos', 'startFilePos', 'endFilePos'. The option defaults to the
* first three. For more info see getNextToken() docs.
*/
public function __construct(array $options = []) {
// Create Map from internal tokens to PhpParser tokens.
$this->defineCompatibilityTokens();
$this->tokenMap = $this->createTokenMap();
$this->identifierTokens = $this->createIdentifierTokenMap();
// map of tokens to drop while lexing (the map is only used for isset lookup,
// that's why the value is simply set to 1; the value is never actually used.)
$this->dropTokens = array_fill_keys(
[\T_WHITESPACE, \T_OPEN_TAG, \T_COMMENT, \T_DOC_COMMENT, \T_BAD_CHARACTER], 1
);
$defaultAttributes = ['comments', 'startLine', 'endLine'];
$usedAttributes = array_fill_keys($options['usedAttributes'] ?? $defaultAttributes, true);
// Create individual boolean properties to make these checks faster.
$this->attributeStartLineUsed = isset($usedAttributes['startLine']);
$this->attributeEndLineUsed = isset($usedAttributes['endLine']);
$this->attributeStartTokenPosUsed = isset($usedAttributes['startTokenPos']);
$this->attributeEndTokenPosUsed = isset($usedAttributes['endTokenPos']);
$this->attributeStartFilePosUsed = isset($usedAttributes['startFilePos']);
$this->attributeEndFilePosUsed = isset($usedAttributes['endFilePos']);
$this->attributeCommentsUsed = isset($usedAttributes['comments']);
}
/**
* Initializes the lexer for lexing the provided source code.
*
* This function does not throw if lexing errors occur. Instead, errors may be retrieved using
* the getErrors() method.
*
* @param string $code The source code to lex
* @param ErrorHandler|null $errorHandler Error handler to use for lexing errors. Defaults to
* ErrorHandler\Throwing
*/
public function startLexing(string $code, ErrorHandler $errorHandler = null) {
if (null === $errorHandler) {
$errorHandler = new ErrorHandler\Throwing();
}
$this->code = $code; // keep the code around for __halt_compiler() handling
$this->pos = -1;
$this->line = 1;
$this->filePos = 0;
// If inline HTML occurs without preceding code, treat it as if it had a leading newline.
// This ensures proper composability, because having a newline is the "safe" assumption.
$this->prevCloseTagHasNewline = true;
$scream = ini_set('xdebug.scream', '0');
$this->tokens = @token_get_all($code);
$this->postprocessTokens($errorHandler);
if (false !== $scream) {
ini_set('xdebug.scream', $scream);
}
}
private function handleInvalidCharacterRange($start, $end, $line, ErrorHandler $errorHandler) {
$tokens = [];
for ($i = $start; $i < $end; $i++) {
$chr = $this->code[$i];
if ($chr === "\0") {
// PHP cuts error message after null byte, so need special case
$errorMsg = 'Unexpected null byte';
} else {
$errorMsg = sprintf(
'Unexpected character "%s" (ASCII %d)', $chr, ord($chr)
);
}
$tokens[] = [\T_BAD_CHARACTER, $chr, $line];
$errorHandler->handleError(new Error($errorMsg, [
'startLine' => $line,
'endLine' => $line,
'startFilePos' => $i,
'endFilePos' => $i,
]));
}
return $tokens;
}
/**
* Check whether comment token is unterminated.
*
* @return bool
*/
private function isUnterminatedComment($token) : bool {
return ($token[0] === \T_COMMENT || $token[0] === \T_DOC_COMMENT)
&& substr($token[1], 0, 2) === '/*'
&& substr($token[1], -2) !== '*/';
}
protected function postprocessTokens(ErrorHandler $errorHandler) {
// PHP's error handling for token_get_all() is rather bad, so if we want detailed
// error information we need to compute it ourselves. Invalid character errors are
// detected by finding "gaps" in the token array. Unterminated comments are detected
// by checking if a trailing comment has a "*/" at the end.
//
// Additionally, we perform a number of canonicalizations here:
// * Use the PHP 8.0 comment format, which does not include trailing whitespace anymore.
// * Use PHP 8.0 T_NAME_* tokens.
// * Use PHP 8.1 T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG and
// T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG tokens used to disambiguate intersection types.
$filePos = 0;
$line = 1;
$numTokens = \count($this->tokens);
for ($i = 0; $i < $numTokens; $i++) {
$token = $this->tokens[$i];
// Since PHP 7.4 invalid characters are represented by a T_BAD_CHARACTER token.
// In this case we only need to emit an error.
if ($token[0] === \T_BAD_CHARACTER) {
$this->handleInvalidCharacterRange($filePos, $filePos + 1, $line, $errorHandler);
}
if ($token[0] === \T_COMMENT && substr($token[1], 0, 2) !== '/*'
&& preg_match('/(\r\n|\n|\r)$/D', $token[1], $matches)) {
$trailingNewline = $matches[0];
$token[1] = substr($token[1], 0, -strlen($trailingNewline));
$this->tokens[$i] = $token;
if (isset($this->tokens[$i + 1]) && $this->tokens[$i + 1][0] === \T_WHITESPACE) {
// Move trailing newline into following T_WHITESPACE token, if it already exists.
$this->tokens[$i + 1][1] = $trailingNewline . $this->tokens[$i + 1][1];
$this->tokens[$i + 1][2]--;
} else {
// Otherwise, we need to create a new T_WHITESPACE token.
array_splice($this->tokens, $i + 1, 0, [
[\T_WHITESPACE, $trailingNewline, $line],
]);
$numTokens++;
}
}
// Emulate PHP 8 T_NAME_* tokens, by combining sequences of T_NS_SEPARATOR and T_STRING
// into a single token.
if (\is_array($token)
&& ($token[0] === \T_NS_SEPARATOR || isset($this->identifierTokens[$token[0]]))) {
$lastWasSeparator = $token[0] === \T_NS_SEPARATOR;
$text = $token[1];
for ($j = $i + 1; isset($this->tokens[$j]); $j++) {
if ($lastWasSeparator) {
if (!isset($this->identifierTokens[$this->tokens[$j][0]])) {
break;
}
$lastWasSeparator = false;
} else {
if ($this->tokens[$j][0] !== \T_NS_SEPARATOR) {
break;
}
$lastWasSeparator = true;
}
$text .= $this->tokens[$j][1];
}
if ($lastWasSeparator) {
// Trailing separator is not part of the name.
$j--;
$text = substr($text, 0, -1);
}
if ($j > $i + 1) {
if ($token[0] === \T_NS_SEPARATOR) {
$type = \T_NAME_FULLY_QUALIFIED;
} else if ($token[0] === \T_NAMESPACE) {
$type = \T_NAME_RELATIVE;
} else {
$type = \T_NAME_QUALIFIED;
}
$token = [$type, $text, $line];
array_splice($this->tokens, $i, $j - $i, [$token]);
$numTokens -= $j - $i - 1;
}
}
if ($token === '&') {
$next = $i + 1;
while (isset($this->tokens[$next]) && $this->tokens[$next][0] === \T_WHITESPACE) {
$next++;
}
$followedByVarOrVarArg = isset($this->tokens[$next]) &&
($this->tokens[$next][0] === \T_VARIABLE || $this->tokens[$next][0] === \T_ELLIPSIS);
$this->tokens[$i] = $token = [
$followedByVarOrVarArg
? \T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG
: \T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG,
'&',
$line,
];
}
$tokenValue = \is_string($token) ? $token : $token[1];
$tokenLen = \strlen($tokenValue);
if (substr($this->code, $filePos, $tokenLen) !== $tokenValue) {
// Something is missing, must be an invalid character
$nextFilePos = strpos($this->code, $tokenValue, $filePos);
$badCharTokens = $this->handleInvalidCharacterRange(
$filePos, $nextFilePos, $line, $errorHandler);
$filePos = (int) $nextFilePos;
array_splice($this->tokens, $i, 0, $badCharTokens);
$numTokens += \count($badCharTokens);
$i += \count($badCharTokens);
}
$filePos += $tokenLen;
$line += substr_count($tokenValue, "\n");
}
if ($filePos !== \strlen($this->code)) {
if (substr($this->code, $filePos, 2) === '/*') {
// Unlike PHP, HHVM will drop unterminated comments entirely
$comment = substr($this->code, $filePos);
$errorHandler->handleError(new Error('Unterminated comment', [
'startLine' => $line,
'endLine' => $line + substr_count($comment, "\n"),
'startFilePos' => $filePos,
'endFilePos' => $filePos + \strlen($comment),
]));
// Emulate the PHP behavior
$isDocComment = isset($comment[3]) && $comment[3] === '*';
$this->tokens[] = [$isDocComment ? \T_DOC_COMMENT : \T_COMMENT, $comment, $line];
} else {
// Invalid characters at the end of the input
$badCharTokens = $this->handleInvalidCharacterRange(
$filePos, \strlen($this->code), $line, $errorHandler);
$this->tokens = array_merge($this->tokens, $badCharTokens);
}
return;
}
if (count($this->tokens) > 0) {
// Check for unterminated comment
$lastToken = $this->tokens[count($this->tokens) - 1];
if ($this->isUnterminatedComment($lastToken)) {
$errorHandler->handleError(new Error('Unterminated comment', [
'startLine' => $line - substr_count($lastToken[1], "\n"),
'endLine' => $line,
'startFilePos' => $filePos - \strlen($lastToken[1]),
'endFilePos' => $filePos,
]));
}
}
}
/**
* Fetches the next token.
*
* The available attributes are determined by the 'usedAttributes' option, which can
* be specified in the constructor. The following attributes are supported:
*
* * 'comments' => Array of PhpParser\Comment or PhpParser\Comment\Doc instances,
* representing all comments that occurred between the previous
* non-discarded token and the current one.
* * 'startLine' => Line in which the node starts.
* * 'endLine' => Line in which the node ends.
* * 'startTokenPos' => Offset into the token array of the first token in the node.
* * 'endTokenPos' => Offset into the token array of the last token in the node.
* * 'startFilePos' => Offset into the code string of the first character that is part of the node.
* * 'endFilePos' => Offset into the code string of the last character that is part of the node.
*
* @param mixed $value Variable to store token content in
* @param mixed $startAttributes Variable to store start attributes in
* @param mixed $endAttributes Variable to store end attributes in
*
* @return int Token id
*/
public function getNextToken(&$value = null, &$startAttributes = null, &$endAttributes = null) : int {
$startAttributes = [];
$endAttributes = [];
while (1) {
if (isset($this->tokens[++$this->pos])) {
$token = $this->tokens[$this->pos];
} else {
// EOF token with ID 0
$token = "\0";
}
if ($this->attributeStartLineUsed) {
$startAttributes['startLine'] = $this->line;
}
if ($this->attributeStartTokenPosUsed) {
$startAttributes['startTokenPos'] = $this->pos;
}
if ($this->attributeStartFilePosUsed) {
$startAttributes['startFilePos'] = $this->filePos;
}
if (\is_string($token)) {
$value = $token;
if (isset($token[1])) {
// bug in token_get_all
$this->filePos += 2;
$id = ord('"');
} else {
$this->filePos += 1;
$id = ord($token);
}
} elseif (!isset($this->dropTokens[$token[0]])) {
$value = $token[1];
$id = $this->tokenMap[$token[0]];
if (\T_CLOSE_TAG === $token[0]) {
$this->prevCloseTagHasNewline = false !== strpos($token[1], "\n")
|| false !== strpos($token[1], "\r");
} elseif (\T_INLINE_HTML === $token[0]) {
$startAttributes['hasLeadingNewline'] = $this->prevCloseTagHasNewline;
}
$this->line += substr_count($value, "\n");
$this->filePos += \strlen($value);
} else {
$origLine = $this->line;
$origFilePos = $this->filePos;
$this->line += substr_count($token[1], "\n");
$this->filePos += \strlen($token[1]);
if (\T_COMMENT === $token[0] || \T_DOC_COMMENT === $token[0]) {
if ($this->attributeCommentsUsed) {
$comment = \T_DOC_COMMENT === $token[0]
? new Comment\Doc($token[1],
$origLine, $origFilePos, $this->pos,
$this->line, $this->filePos - 1, $this->pos)
: new Comment($token[1],
$origLine, $origFilePos, $this->pos,
$this->line, $this->filePos - 1, $this->pos);
$startAttributes['comments'][] = $comment;
}
}
continue;
}
if ($this->attributeEndLineUsed) {
$endAttributes['endLine'] = $this->line;
}
if ($this->attributeEndTokenPosUsed) {
$endAttributes['endTokenPos'] = $this->pos;
}
if ($this->attributeEndFilePosUsed) {
$endAttributes['endFilePos'] = $this->filePos - 1;
}
return $id;
}
throw new \RuntimeException('Reached end of lexer loop');
}
/**
* Returns the token array for current code.
*
* The token array is in the same format as provided by the
* token_get_all() function and does not discard tokens (i.e.
* whitespace and comments are included). The token position
* attributes are against this token array.
*
* @return array Array of tokens in token_get_all() format
*/
public function getTokens() : array {
return $this->tokens;
}
/**
* Handles __halt_compiler() by returning the text after it.
*
* @return string Remaining text
*/
public function handleHaltCompiler() : string {
// text after T_HALT_COMPILER, still including ();
$textAfter = substr($this->code, $this->filePos);
// ensure that it is followed by ();
// this simplifies the situation, by not allowing any comments
// in between of the tokens.
if (!preg_match('~^\s*\(\s*\)\s*(?:;|\?>\r?\n?)~', $textAfter, $matches)) {
throw new Error('__HALT_COMPILER must be followed by "();"');
}
// prevent the lexer from returning any further tokens
$this->pos = count($this->tokens);
// return with (); removed
return substr($textAfter, strlen($matches[0]));
}
private function defineCompatibilityTokens() {
static $compatTokensDefined = false;
if ($compatTokensDefined) {
return;
}
$compatTokens = [
// PHP 7.4
'T_BAD_CHARACTER',
'T_FN',
'T_COALESCE_EQUAL',
// PHP 8.0
'T_NAME_QUALIFIED',
'T_NAME_FULLY_QUALIFIED',
'T_NAME_RELATIVE',
'T_MATCH',
'T_NULLSAFE_OBJECT_OPERATOR',
'T_ATTRIBUTE',
// PHP 8.1
'T_ENUM',
'T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG',
'T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG',
];
// PHP-Parser might be used together with another library that also emulates some or all
// of these tokens. Perform a sanity-check that all already defined tokens have been
// assigned a unique ID.
$usedTokenIds = [];
foreach ($compatTokens as $token) {
if (\defined($token)) {
$tokenId = \constant($token);
$clashingToken = $usedTokenIds[$tokenId] ?? null;
if ($clashingToken !== null) {
throw new \Error(sprintf(
'Token %s has same ID as token %s, ' .
'you may be using a library with broken token emulation',
$token, $clashingToken
));
}
$usedTokenIds[$tokenId] = $token;
}
}
// Now define any tokens that have not yet been emulated. Try to assign IDs from -1
// downwards, but skip any IDs that may already be in use.
$newTokenId = -1;
foreach ($compatTokens as $token) {
if (!\defined($token)) {
while (isset($usedTokenIds[$newTokenId])) {
$newTokenId--;
}
\define($token, $newTokenId);
$newTokenId--;
}
}
$compatTokensDefined = true;
}
/**
* Creates the token map.
*
* The token map maps the PHP internal token identifiers
* to the identifiers used by the Parser. Additionally it
* maps T_OPEN_TAG_WITH_ECHO to T_ECHO and T_CLOSE_TAG to ';'.
*
* @return array The token map
*/
protected function createTokenMap() : array {
$tokenMap = [];
// 256 is the minimum possible token number, as everything below
// it is an ASCII value
for ($i = 256; $i < 1000; ++$i) {
if (\T_DOUBLE_COLON === $i) {
// T_DOUBLE_COLON is equivalent to T_PAAMAYIM_NEKUDOTAYIM
$tokenMap[$i] = Tokens::T_PAAMAYIM_NEKUDOTAYIM;
} elseif(\T_OPEN_TAG_WITH_ECHO === $i) {
// T_OPEN_TAG_WITH_ECHO with dropped T_OPEN_TAG results in T_ECHO
$tokenMap[$i] = Tokens::T_ECHO;
} elseif(\T_CLOSE_TAG === $i) {
// T_CLOSE_TAG is equivalent to ';'
$tokenMap[$i] = ord(';');
} elseif ('UNKNOWN' !== $name = token_name($i)) {
if ('T_HASHBANG' === $name) {
// HHVM uses a special token for #! hashbang lines
$tokenMap[$i] = Tokens::T_INLINE_HTML;
} elseif (defined($name = Tokens::class . '::' . $name)) {
// Other tokens can be mapped directly
$tokenMap[$i] = constant($name);
}
}
}
// HHVM uses a special token for numbers that overflow to double
if (defined('T_ONUMBER')) {
$tokenMap[\T_ONUMBER] = Tokens::T_DNUMBER;
}
// HHVM also has a separate token for the __COMPILER_HALT_OFFSET__ constant
if (defined('T_COMPILER_HALT_OFFSET')) {
$tokenMap[\T_COMPILER_HALT_OFFSET] = Tokens::T_STRING;
}
// Assign tokens for which we define compatibility constants, as token_name() does not know them.
$tokenMap[\T_FN] = Tokens::T_FN;
$tokenMap[\T_COALESCE_EQUAL] = Tokens::T_COALESCE_EQUAL;
$tokenMap[\T_NAME_QUALIFIED] = Tokens::T_NAME_QUALIFIED;
$tokenMap[\T_NAME_FULLY_QUALIFIED] = Tokens::T_NAME_FULLY_QUALIFIED;
$tokenMap[\T_NAME_RELATIVE] = Tokens::T_NAME_RELATIVE;
$tokenMap[\T_MATCH] = Tokens::T_MATCH;
$tokenMap[\T_NULLSAFE_OBJECT_OPERATOR] = Tokens::T_NULLSAFE_OBJECT_OPERATOR;
$tokenMap[\T_ATTRIBUTE] = Tokens::T_ATTRIBUTE;
$tokenMap[\T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG] = Tokens::T_AMPERSAND_NOT_FOLLOWED_BY_VAR_OR_VARARG;
$tokenMap[\T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG] = Tokens::T_AMPERSAND_FOLLOWED_BY_VAR_OR_VARARG;
$tokenMap[\T_ENUM] = Tokens::T_ENUM;
return $tokenMap;
}
private function createIdentifierTokenMap(): array {
// Based on semi_reserved production.
return array_fill_keys([
\T_STRING,
\T_STATIC, \T_ABSTRACT, \T_FINAL, \T_PRIVATE, \T_PROTECTED, \T_PUBLIC,
\T_INCLUDE, \T_INCLUDE_ONCE, \T_EVAL, \T_REQUIRE, \T_REQUIRE_ONCE, \T_LOGICAL_OR, \T_LOGICAL_XOR, \T_LOGICAL_AND,
\T_INSTANCEOF, \T_NEW, \T_CLONE, \T_EXIT, \T_IF, \T_ELSEIF, \T_ELSE, \T_ENDIF, \T_ECHO, \T_DO, \T_WHILE,
\T_ENDWHILE, \T_FOR, \T_ENDFOR, \T_FOREACH, \T_ENDFOREACH, \T_DECLARE, \T_ENDDECLARE, \T_AS, \T_TRY, \T_CATCH,
\T_FINALLY, \T_THROW, \T_USE, \T_INSTEADOF, \T_GLOBAL, \T_VAR, \T_UNSET, \T_ISSET, \T_EMPTY, \T_CONTINUE, \T_GOTO,
\T_FUNCTION, \T_CONST, \T_RETURN, \T_PRINT, \T_YIELD, \T_LIST, \T_SWITCH, \T_ENDSWITCH, \T_CASE, \T_DEFAULT,
\T_BREAK, \T_ARRAY, \T_CALLABLE, \T_EXTENDS, \T_IMPLEMENTS, \T_NAMESPACE, \T_TRAIT, \T_INTERFACE, \T_CLASS,
\T_CLASS_C, \T_TRAIT_C, \T_FUNC_C, \T_METHOD_C, \T_LINE, \T_FILE, \T_DIR, \T_NS_C, \T_HALT_COMPILER, \T_FN,
\T_MATCH,
], true);
}
}