ClassCollector.php

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<?php
class ClassCollector {
 
    protected $namespace = '';
 
    protected $classes;
 
    protected $startToken;
 
    protected $tokens;
 
    protected $alias;
 
    public function getClasses( $code ) {
        $this->namespace = '';
        $this->classes = [];
        $this->startToken = null;
        $this->alias = null;
        $this->tokens = [];
 
        // HACK: The PHP tokenizer is slow (T225730).
        // Speed it up by reducing the input to the three kinds of statement we care about:
        // - namespace X;
        // - [final] [abstract] class X … {}
        // - class_alias( … );
        $lines = [];
        $matches = null;
        preg_match_all(
            // phpcs:ignore Generic.Files.LineLength.TooLong
            '#^\t*(?:namespace |(final )?(abstract )?(class|interface|trait) |class_alias\‍()[^;{]+[;{]\s*\}?#m',
            $code,
            $matches
        );
        if ( isset( $matches[0][0] ) ) {
            foreach ( $matches[0] as $match ) {
                $match = trim( $match );
                if ( substr( $match, -1 ) === '{' ) {
                    // Keep it balanced
                    $match .= '}';
                }
                $lines[] = $match;
            }
        }
        $code = '<?php ' . implode( "\n", $lines ) . "\n";
 
        foreach ( token_get_all( $code ) as $token ) {
            if ( $this->startToken === null ) {
                $this->tryBeginExpect( $token );
            } else {
                $this->tryEndExpect( $token );
            }
        }
 
        return $this->classes;
    }
 
    protected function tryBeginExpect( $token ) {
        if ( is_string( $token ) ) {
            return;
        }
        // Note: When changing class name discovery logic,
        // AutoLoaderStructureTest.php may also need to be updated.
        switch ( $token[0] ) {
            case T_NAMESPACE:
            case T_CLASS:
            case T_INTERFACE:
            case T_TRAIT:
            case T_DOUBLE_COLON:
            case T_NEW:
                $this->startToken = $token;
                break;
            case T_STRING:
                if ( $token[1] === 'class_alias' ) {
                    $this->startToken = $token;
                    $this->alias = [];
                }
        }
    }
 
    protected function tryEndExpect( $token ) {
        // @phan-suppress-next-line PhanTypeArraySuspiciousNullable
        switch ( $this->startToken[0] ) {
            case T_DOUBLE_COLON:
                // Skip over T_CLASS after T_DOUBLE_COLON because this is something like
                // "self::static" which accesses the class name. It doesn't define a new class.
                $this->startToken = null;
                break;
            case T_NEW:
                // Skip over T_CLASS after T_NEW because this is a PHP 7 anonymous class.
                if ( !is_array( $token ) || $token[0] !== T_WHITESPACE ) {
                    $this->startToken = null;
                }
                break;
            case T_NAMESPACE:
                if ( $token === ';' || $token === '{' ) {
                    $this->namespace = $this->implodeTokens() . '\\';
                } else {
                    $this->tokens[] = $token;
                }
                break;
 
            case T_STRING:
                if ( $this->alias !== null ) {
                    // Flow 1 - Two string literals:
                    // - T_STRING  class_alias
                    // - '('
                    // - T_CONSTANT_ENCAPSED_STRING 'TargetClass'
                    // - ','
                    // - T_WHITESPACE
                    // - T_CONSTANT_ENCAPSED_STRING 'AliasName'
                    // - ')'
                    // Flow 2 - Use of ::class syntax for first parameter
                    // - T_STRING  class_alias
                    // - '('
                    // - T_STRING TargetClass
                    // - T_DOUBLE_COLON ::
                    // - T_CLASS class
                    // - ','
                    // - T_WHITESPACE
                    // - T_CONSTANT_ENCAPSED_STRING 'AliasName'
                    // - ')'
                    if ( $token === '(' ) {
                        // Start of a function call to class_alias()
                        $this->alias = [ 'target' => false, 'name' => false ];
                    } elseif ( $token === ',' ) {
                        // Record that we're past the first parameter
                        if ( $this->alias['target'] === false ) {
                            $this->alias['target'] = true;
                        }
                    } elseif ( is_array( $token ) && $token[0] === T_CONSTANT_ENCAPSED_STRING ) {
                        if ( $this->alias['target'] === true ) {
                            // We already saw a first argument, this must be the second.
                            // Strip quotes from the string literal.
                            $this->alias['name'] = self::stripQuotes( $token[1] );
                        }
                    } elseif ( $token === ')' ) {
                        // End of function call
                        $this->classes[] = $this->alias['name'];
                        $this->alias = null;
                        $this->startToken = null;
                    } elseif ( !is_array( $token ) || (
                            $token[0] !== T_STRING &&
                            $token[0] !== T_DOUBLE_COLON &&
                            $token[0] !== T_CLASS &&
                            $token[0] !== T_WHITESPACE
                        ) ) {
                        // Ignore this call to class_alias() - compat/Timestamp.php
                        $this->alias = null;
                        $this->startToken = null;
                    }
                }
                break;
 
            case T_CLASS:
            case T_INTERFACE:
            case T_TRAIT:
                $this->tokens[] = $token;
                if ( is_array( $token ) && $token[0] === T_STRING ) {
                    $this->classes[] = $this->namespace . $this->implodeTokens();
                }
        }
    }
 
    private static function stripQuotes( $str ) {
        return str_replace( '\\\\', '\\', substr( $str, 1, -1 ) );
    }
 
    protected function implodeTokens() {
        $content = [];
        foreach ( $this->tokens as $token ) {
            $content[] = is_string( $token ) ? $token : $token[1];
        }
 
        $this->tokens = [];
        $this->startToken = null;
 
        return trim( implode( '', $content ), " \n\t" );
    }
}