mirror of
https://github.com/danog/PHP-Parser.git
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d98a65086b
The emulative lexer is a single dirty hack so it needs a few more comments :)
180 lines
7.7 KiB
PHP
180 lines
7.7 KiB
PHP
<?php
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/**
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* ATTENTION: This code is WRITE-ONLY. Do not try to read it.
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*/
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class PHPParser_Lexer_Emulative extends PHPParser_Lexer
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{
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protected static $keywords = array(
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// PHP 5.4
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'callable' => PHPParser_Parser::T_CALLABLE,
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'insteadof' => PHPParser_Parser::T_INSTEADOF,
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'trait' => PHPParser_Parser::T_TRAIT,
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'__trait__' => PHPParser_Parser::T_TRAIT_C,
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// PHP 5.3
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'__dir__' => PHPParser_Parser::T_DIR,
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'goto' => PHPParser_Parser::T_GOTO,
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'namespace' => PHPParser_Parser::T_NAMESPACE,
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'__namespace__' => PHPParser_Parser::T_NS_C,
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);
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protected $inObjectAccess;
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public function __construct($code) {
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$this->inObjectAccess = false;
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// on PHP 5.4 don't do anything
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if (version_compare(PHP_VERSION, '5.4.0RC1', '>=')) {
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parent::__construct($code);
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} else {
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$code = $this->preprocessCode($code);
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parent::__construct($code);
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$this->postprocessTokens();
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}
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}
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/*
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* Replaces new features in the code by ~__EMU__{NAME}__{DATA}__~ sequences.
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* ~LABEL~ is never valid PHP code, that's why we can (to some degree) safely
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* use it here.
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* Later when preprocessing the tokens these sequences will either be replaced
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* by real tokens or replaced with their original content (e.g. if they occured
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* inside a string, i.e. a place where they don't have a special meaning).
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*/
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protected function preprocessCode($code) {
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// binary notation (0b010101101001...)
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$code = preg_replace('(\b0b[01]+\b)', '~__EMU__BINARY__$0__~', $code);
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if (version_compare(PHP_VERSION, '5.3.0', '<')) {
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// namespace separator (backslash not followed by some special characters,
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// which are not valid after a NS separator, but would cause problems with
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// escape sequence parsing if one would replace the backslash there)
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$code = preg_replace('(\\\\(?!["\'`$\\\\]))', '~__EMU__NS__~', $code);
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// nowdoc (<<<'ABC'\ncontent\nABC;)
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$code = preg_replace_callback(
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'((*BSR_ANYCRLF) # set \R to (?>\r\n|\r|\n)
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(b?<<<[\t ]*\'([a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*)\'\R) # opening token
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((?:(?!\2;?\R).*\R)*) # content
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(\2) # closing token
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(?=;?\R) # must be followed by newline (with optional semicolon)
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)x',
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array($this, 'encodeNowdocCallback'),
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$code
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);
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}
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return $code;
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}
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/*
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* As nowdocs can have arbitrary content but LABELs can only contain a certain
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* range of characters, the nowdoc content is encoded as hex and separated by
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* 'x' tokens. So the result of the encoding will look like this:
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* ~__EMU__NOWDOC__{HEX(START_TOKEN)}x{HEX(CONTENT)}x{HEX(END_TOKEN)}~
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*/
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public function encodeNowdocCallback(array $matches) {
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return '~__EMU__NOWDOC__'
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. bin2hex($matches[1]) . 'x' . bin2hex($matches[3]) . 'x' . bin2hex($matches[4])
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. '__~';
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}
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/*
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* Replaces the ~__EMU__...~ sequences with real tokens or their original
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* value.
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*/
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protected function postprocessTokens() {
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// we need to manually iterate and manage a count because we'll change
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// the tokens array on the way
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for ($i = 0, $c = count($this->tokens); $i < $c; ++$i) {
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// first check that the following tokens are form ~LABEL~,
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// then match the __EMU__... sequence.
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if ('~' === $this->tokens[$i]
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&& isset($this->tokens[$i + 2])
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&& '~' === $this->tokens[$i + 2]
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&& T_STRING === $this->tokens[$i + 1][0]
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&& preg_match('(^__EMU__([A-Z]++)__(?:([A-Za-z0-9]++)__)?$)', $this->tokens[$i + 1][1], $matches)
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) {
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if ('BINARY' === $matches[1]) {
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// the binary number can either be an integer or a double, so return a LNUMBER
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// or DNUMBER respectively
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$replace = array(
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array(is_int(bindec($matches[2])) ? T_LNUMBER : T_DNUMBER, $matches[2], $this->tokens[$i + 1][2])
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);
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} elseif ('NS' === $matches[1]) {
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// a \ single char token is returned here and replaced by a
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// PHPParser_Parser::T_NS_SEPARATOR token in ->lex(). This hacks around the
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// limitations arising from T_NS_SEPARATOR not being defined on 5.3
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$replace = array('\\');
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} elseif ('NOWDOC' === $matches[1]) {
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// decode the encoded nowdoc payload; pack('H*' is bin2hex( for 5.3
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list($start, $content, $end) = explode('x', $matches[2]);
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list($start, $content, $end) = array(pack('H*', $start), pack('H*', $content), pack('H*', $end));
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$replace = array();
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$replace[] = array(T_START_HEREDOC, $start, $this->tokens[$i + 1][2]);
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if ('' !== $content) {
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$replace[] = array(T_ENCAPSED_AND_WHITESPACE, $content, -1);
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}
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$replace[] = array(T_END_HEREDOC, $end, -1);
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} else {
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// just ignore all other __EMU__ sequences
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continue;
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}
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array_splice($this->tokens, $i, 3, $replace);
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$c -= 3 - count($replace);
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// for multichar tokens (e.g. strings) replace any ~__EMU__...~ sequences
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// in their content with the original character sequence
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} elseif (is_array($this->tokens[$i])
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&& 0 !== strpos($this->tokens[$i][1], '__EMU__')
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) {
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$this->tokens[$i][1] = preg_replace_callback(
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'(~__EMU__([A-Z]++)__(?:([A-Za-z0-9]++)__)?~)',
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array($this, 'restoreContentCallback'),
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$this->tokens[$i][1]
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);
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}
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}
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}
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/*
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* This method is a callback for restoring EMU sequences in
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* multichar tokens (like strings) to their original value.
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*/
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public function restoreContentCallback(array $matches) {
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if ('BINARY' === $matches[1]) {
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return $matches[2];
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} elseif ('NS' === $matches[1]) {
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return '\\';
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} elseif ('NOWDOC' === $matches[1]) {
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list($start, $content, $end) = explode('x', $matches[2]);
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return pack('H*', $start) . pack('H*', $content) . pack('H*', $end);
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} else {
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return $matches[0];
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}
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}
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public function lex(&$value = null, &$line = null, &$docComment = null) {
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$token = parent::lex($value, $line, $docComment);
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// replace new keywords by their respective tokens. This is not done
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// if we currently are in an object access (e.g. in $obj->namespace
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// "namespace" stays a T_STRING tokens and isn't converted to T_NAMESPACE)
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if (PHPParser_Parser::T_STRING === $token && !$this->inObjectAccess) {
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if (isset(self::$keywords[strtolower($value)])) {
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return self::$keywords[strtolower($value)];
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}
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// backslashes are replaced by T_NS_SEPARATOR tokens
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} elseif (92 === $token) { // ord('\\')
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return PHPParser_Parser::T_NS_SEPARATOR;
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// keep track of whether we currently are in an object access (after ->)
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} elseif (PHPParser_Parser::T_OBJECT_OPERATOR === $token) {
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$this->inObjectAccess = true;
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} else {
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$this->inObjectAccess = false;
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}
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return $token;
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}
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} |