forked from GNUsocial/gnu-social
		
	
		
			
				
	
	
		
			287 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
			
		
		
	
	
			287 lines
		
	
	
		
			11 KiB
		
	
	
	
		
			PHP
		
	
	
	
	
	
<?php
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namespace PhpParser;
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class Lexer
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{
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    protected $code;
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    protected $tokens;
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    protected $pos;
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    protected $line;
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    protected $filePos;
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    protected $tokenMap;
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    protected $dropTokens;
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    protected $usedAttributes;
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    /**
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     * Creates a Lexer.
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     *
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     * @param array $options Options array. Currently only the 'usedAttributes' option is supported,
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     *                       which is an array of attributes to add to the AST nodes. Possible attributes
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     *                       are: 'comments', 'startLine', 'endLine', 'startTokenPos', 'endTokenPos',
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     *                       'startFilePos', 'endFilePos'. The option defaults to the first three.
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     *                       For more info see getNextToken() docs.
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     */
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    public function __construct(array $options = array()) {
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        // map from internal tokens to PhpParser tokens
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        $this->tokenMap = $this->createTokenMap();
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        // map of tokens to drop while lexing (the map is only used for isset lookup,
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        // that's why the value is simply set to 1; the value is never actually used.)
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        $this->dropTokens = array_fill_keys(array(T_WHITESPACE, T_OPEN_TAG), 1);
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        // the usedAttributes member is a map of the used attribute names to a dummy
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        // value (here "true")
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        $options += array(
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            'usedAttributes' => array('comments', 'startLine', 'endLine'),
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        );
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        $this->usedAttributes = array_fill_keys($options['usedAttributes'], true);
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    }
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    /**
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     * Initializes the lexer for lexing the provided source code.
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     *
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     * @param string $code The source code to lex
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     *
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     * @throws Error on lexing errors (unterminated comment or unexpected character)
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     */
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    public function startLexing($code) {
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        $scream = ini_set('xdebug.scream', '0');
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        $this->resetErrors();
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        $this->tokens = @token_get_all($code);
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        $this->handleErrors();
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        if (false !== $scream) {
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            ini_set('xdebug.scream', $scream);
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        }
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        $this->code = $code; // keep the code around for __halt_compiler() handling
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        $this->pos  = -1;
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        $this->line =  1;
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        $this->filePos = 0;
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    }
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    protected function resetErrors() {
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        // set error_get_last() to defined state by forcing an undefined variable error
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        set_error_handler(function() { return false; }, 0);
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        @$undefinedVariable;
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        restore_error_handler();
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    }
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    protected function handleErrors() {
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        $error = error_get_last();
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        if (preg_match(
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            '~^Unterminated comment starting line ([0-9]+)$~',
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            $error['message'], $matches
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        )) {
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            throw new Error('Unterminated comment', (int) $matches[1]);
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        }
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        if (preg_match(
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            '~^Unexpected character in input:  \'(.)\' \(ASCII=([0-9]+)\)~s',
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            $error['message'], $matches
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        )) {
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            throw new Error(sprintf(
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                'Unexpected character "%s" (ASCII %d)',
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                $matches[1], $matches[2]
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            ));
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        }
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        // PHP cuts error message after null byte, so need special case
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        if (preg_match('~^Unexpected character in input:  \'$~', $error['message'])) {
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            throw new Error('Unexpected null byte');
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        }
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    }
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    /**
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     * Fetches the next token.
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     *
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     * The available attributes are determined by the 'usedAttributes' option, which can
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     * be specified in the constructor. The following attributes are supported:
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     *
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     *  * 'comments'      => Array of PhpParser\Comment or PhpParser\Comment\Doc instances,
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     *                       representing all comments that occurred between the previous
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     *                       non-discarded token and the current one.
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     *  * 'startLine'     => Line in which the node starts.
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     *  * 'endLine'       => Line in which the node ends.
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     *  * 'startTokenPos' => Offset into the token array of the first token in the node.
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     *  * 'endTokenPos'   => Offset into the token array of the last token in the node.
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     *  * 'startFilePos'  => Offset into the code string of the first character that is part of the node.
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     *  * 'endFilePos'    => Offset into the code string of the last character that is part of the node
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     *
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     * @param mixed $value           Variable to store token content in
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     * @param mixed $startAttributes Variable to store start attributes in
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     * @param mixed $endAttributes   Variable to store end attributes in
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     *
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     * @return int Token id
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     */
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    public function getNextToken(&$value = null, &$startAttributes = null, &$endAttributes = null) {
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        $startAttributes = array();
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        $endAttributes   = array();
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        while (1) {
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            if (isset($this->tokens[++$this->pos])) {
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                $token = $this->tokens[$this->pos];
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            } else {
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                // EOF token with ID 0
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                $token = "\0";
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            }
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            if (isset($this->usedAttributes['startTokenPos'])) {
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                $startAttributes['startTokenPos'] = $this->pos;
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            }
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            if (isset($this->usedAttributes['startFilePos'])) {
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                $startAttributes['startFilePos'] = $this->filePos;
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            }
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            if (is_string($token)) {
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                // bug in token_get_all
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                if ('b"' === $token) {
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                    $value = 'b"';
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                    $this->filePos += 2;
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                    $id = ord('"');
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                } else {
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                    $value = $token;
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                    $this->filePos += 1;
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                    $id = ord($token);
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                }
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                if (isset($this->usedAttributes['startLine'])) {
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                    $startAttributes['startLine'] = $this->line;
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                }
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                if (isset($this->usedAttributes['endLine'])) {
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                    $endAttributes['endLine'] = $this->line;
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                }
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                if (isset($this->usedAttributes['endTokenPos'])) {
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                    $endAttributes['endTokenPos'] = $this->pos;
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                }
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                if (isset($this->usedAttributes['endFilePos'])) {
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                    $endAttributes['endFilePos'] = $this->filePos - 1;
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                }
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                return $id;
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            } else {
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                $this->line += substr_count($token[1], "\n");
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                $this->filePos += strlen($token[1]);
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                if (T_COMMENT === $token[0]) {
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                    if (isset($this->usedAttributes['comments'])) {
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                        $startAttributes['comments'][] = new Comment($token[1], $token[2]);
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                    }
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                } elseif (T_DOC_COMMENT === $token[0]) {
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                    if (isset($this->usedAttributes['comments'])) {
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                        $startAttributes['comments'][] = new Comment\Doc($token[1], $token[2]);
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                    }
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                } elseif (!isset($this->dropTokens[$token[0]])) {
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                    $value = $token[1];
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                    if (isset($this->usedAttributes['startLine'])) {
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                        $startAttributes['startLine'] = $token[2];
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                    }
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                    if (isset($this->usedAttributes['endLine'])) {
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                        $endAttributes['endLine'] = $this->line;
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                    }
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                    if (isset($this->usedAttributes['endTokenPos'])) {
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                        $endAttributes['endTokenPos'] = $this->pos;
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                    }
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                    if (isset($this->usedAttributes['endFilePos'])) {
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                        $endAttributes['endFilePos'] = $this->filePos - 1;
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                    }
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                    return $this->tokenMap[$token[0]];
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                }
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            }
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        }
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        throw new \RuntimeException('Reached end of lexer loop');
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    }
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    /**
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     * Returns the token array for current code.
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     *
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     * The token array is in the same format as provided by the
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     * token_get_all() function and does not discard tokens (i.e.
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     * whitespace and comments are included). The token position
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     * attributes are against this token array.
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     *
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     * @return array Array of tokens in token_get_all() format
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     */
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    public function getTokens() {
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        return $this->tokens;
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    }
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    /**
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     * Handles __halt_compiler() by returning the text after it.
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     *
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     * @return string Remaining text
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     */
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    public function handleHaltCompiler() {
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        // text after T_HALT_COMPILER, still including ();
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        $textAfter = substr($this->code, $this->filePos);
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        // ensure that it is followed by ();
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        // this simplifies the situation, by not allowing any comments
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        // in between of the tokens.
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        if (!preg_match('~^\s*\(\s*\)\s*(?:;|\?>\r?\n?)~', $textAfter, $matches)) {
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            throw new Error('__HALT_COMPILER must be followed by "();"');
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        }
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        // prevent the lexer from returning any further tokens
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        $this->pos = count($this->tokens);
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        // return with (); removed
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        return (string) substr($textAfter, strlen($matches[0])); // (string) converts false to ''
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    }
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    /**
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     * Creates the token map.
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     *
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     * The token map maps the PHP internal token identifiers
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     * to the identifiers used by the Parser. Additionally it
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     * maps T_OPEN_TAG_WITH_ECHO to T_ECHO and T_CLOSE_TAG to ';'.
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     *
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     * @return array The token map
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     */
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    protected function createTokenMap() {
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        $tokenMap = array();
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        // 256 is the minimum possible token number, as everything below
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        // it is an ASCII value
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        for ($i = 256; $i < 1000; ++$i) {
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            if (T_DOUBLE_COLON === $i) {
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                // T_DOUBLE_COLON is equivalent to T_PAAMAYIM_NEKUDOTAYIM
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                $tokenMap[$i] = Parser::T_PAAMAYIM_NEKUDOTAYIM;
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            } elseif(T_OPEN_TAG_WITH_ECHO === $i) {
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                // T_OPEN_TAG_WITH_ECHO with dropped T_OPEN_TAG results in T_ECHO
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                $tokenMap[$i] = Parser::T_ECHO;
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            } elseif(T_CLOSE_TAG === $i) {
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                // T_CLOSE_TAG is equivalent to ';'
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                $tokenMap[$i] = ord(';');
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            } elseif ('UNKNOWN' !== $name = token_name($i)) {
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                if ('T_HASHBANG' === $name) {
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                    // HHVM uses a special token for #! hashbang lines
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                    $tokenMap[$i] = Parser::T_INLINE_HTML;
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                } else if (defined($name = 'PhpParser\Parser::' . $name)) {
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                    // Other tokens can be mapped directly
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                    $tokenMap[$i] = constant($name);
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                }
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            }
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        }
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        // HHVM uses a special token for numbers that overflow to double
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        if (defined('T_ONUMBER')) {
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            $tokenMap[T_ONUMBER] = Parser::T_DNUMBER;
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        }
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        // HHVM also has a separate token for the __COMPILER_HALT_OFFSET__ constant
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        if (defined('T_COMPILER_HALT_OFFSET')) {
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            $tokenMap[T_COMPILER_HALT_OFFSET] = Parser::T_STRING;
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        }
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        return $tokenMap;
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    }
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}
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