Go\Instrument\Transformer\ConstructorExecutionTransformer

Complexity

Total Complexity

14

Size/Duplication

Total Lines	121
Duplicated Lines	0 %

Coupling/Cohesion

Components	2
Dependencies	5

Test Coverage

Coverage

94.44%

Importance

Changes

0

5 Methods

Rating	Name	Duplication	Size	Complexity
A	getInstance()	0	9	2
B	transform()	0	31	5
A	__get()	0	4	1
A	__call()	0	4	1
B	construct()	0	24	5

<?php
declare(strict_types = 1);
/*
 * Go! AOP framework
 *
 * @copyright Copyright 2014, Lisachenko Alexander <lisachenko.it@gmail.com>
 *
 * This source file is subject to the license that is bundled
 * with this source code in the file LICENSE.
 */

namespace Go\Instrument\Transformer;

use Go\Aop\Framework\ReflectionConstructorInvocation;
use Go\Core\AspectContainer;
use PhpParser\Node;
use PhpParser\NodeTraverser;

/**
 * Transforms the source code to add an ability to intercept new instances creation
 *
 * @see https://github.com/php/php-src/blob/master/Zend/zend_language_parser.y
 *
 */
class ConstructorExecutionTransformer implements SourceTransformer
{
    /**
     * List of constructor invocations per class
     *
     * @var array|ReflectionConstructorInvocation[]
     */
    private static $constructorInvocationsCache = [];

    /**
     * Singletone
     *
     * @return static
     */
    public static function getInstance()
    {
        static $instance;
        if (!$instance) {
            $instance = new static;
        }

        return $instance;
    }

    /**
     * Rewrites all "new" expressions with our implementation
     *
     * @param StreamMetaData $metadata Metadata for source
     *
     * @return string See RESULT_XXX constants in the interface
     */
    public function transform(StreamMetaData $metadata): string
    {
        $newExpressionFinder = new NodeFinderVisitor([Node\Expr\New_::class]);

        // TODO: move this logic into walkSyntaxTree(Visitor $nodeVistor) method
        $traverser = new NodeTraverser();
        $traverser->addVisitor($newExpressionFinder);
        $traverser->traverse($metadata->syntaxTree);

        /** @var Node\Expr\New_[] $newExpressions */
        $newExpressions = $newExpressionFinder->getFoundNodes();

        if (empty($newExpressions)) {
            return self::RESULT_ABSTAIN;
        }

        foreach ($newExpressions as $newExpressionNode) {
            $startPosition = $newExpressionNode->getAttribute('startTokenPos');

            $metadata->tokenStream[$startPosition][1] = '\\' . __CLASS__ . '::getInstance()->{';
            if ($metadata->tokenStream[$startPosition+1][0] === T_WHITESPACE) {
                unset($metadata->tokenStream[$startPosition+1]);
            }
            $isExplicitClass  = $newExpressionNode->class instanceof Node\Name;
            $endClassNamePos  = $newExpressionNode->class->getAttribute('endTokenPos');
            $expressionSuffix = $isExplicitClass ? '::class}' : '}';
            $metadata->tokenStream[$endClassNamePos][1] .= $expressionSuffix;
        }

        return self::RESULT_TRANSFORMED;
    }

    /**
     * Magic interceptor for instance creation
     *
     * @param string $className Name of the class to construct
     *
     * @return object Instance of required object
     */
    public function __get($className)
    {
        return static::construct($className);
    }

    /**
     * Magic interceptor for instance creation
     *
     * @param string $className Name of the class to construct
     * @param array $args Arguments for the constructor
     *
     * @return object Instance of required object
     */
    public function __call($className, array $args)
    {
        return static::construct($className, $args);
    }

    /**
     * Default implementation for accessing joinpoint or creating a new one on-fly
     *
     * @param string $fullClassName Name of the class to create
     * @param array $arguments Arguments for constructor
     *
     * @return object
     */
    protected static function construct(string $fullClassName, array $arguments = [])
    {
        $fullClassName = ltrim($fullClassName, '\\');
        if (!isset(self::$constructorInvocationsCache[$fullClassName])) {
            $invocation = null;
            $dynamicInit = AspectContainer::INIT_PREFIX . ':root';
            try {
                $joinPointsRef = new \ReflectionProperty($fullClassName, '__joinPoints');
                $joinPointsRef->setAccessible(true);
                $joinPoints = $joinPointsRef->getValue();
                if (isset($joinPoints[$dynamicInit])) {
                    $invocation = $joinPoints[$dynamicInit];
                }
            } catch (\ReflectionException $e) {
                $invocation = null;
            }
            if (!$invocation) {
                $invocation = new ReflectionConstructorInvocation($fullClassName, 'root', []);
            }
            self::$constructorInvocationsCache[$fullClassName] = $invocation;
        }

        return self::$constructorInvocationsCache[$fullClassName]->__invoke($arguments);
    }
}