JClaveau\Async\DeferredCallChain

Complexity

Total Complexity

42

Size/Duplication

Total Lines	295
Duplicated Lines	0 %

Importance

Changes	5
Bugs	0	Features	0

12 Methods

Rating	Name	Duplication	Size	Complexity
B	checkTarget()	0	36	10
A	offsetGet()	0	7	1
A	__toString()	0	26	5
A	__call()	0	8	1
A	jsonSerialize()	0	3	1
A	__construct()	0	4	2
A	offsetSet()	0	4	1
B	exceptionTrownFromMagicCall()	0	18	8
B	__invoke()	0	40	8
A	checkMethodIsReallyCallable()	0	26	3
A	offsetUnset()	0	4	1
A	offsetExists()	0	4	1

<?php
/**
 * DeferredCallChain
 *
 * @package php-deferred-callchain
 * @author  Jean Claveau
 */
namespace JClaveau\Async;
use       JClaveau\Async\Exceptions\BadTargetClassException;
use       JClaveau\Async\Exceptions\BadTargetTypeException;
use       JClaveau\Async\Exceptions\UndefinedTargetClassException;
use       JClaveau\Async\Exceptions\BadTargetInterfaceException;
use       JClaveau\Async\Exceptions\TargetAlreadyDefinedException;
use       BadMethodCallException;

/**
 * This class stores an arbitrary stack of calls (methods or array entries access)
 * that will be callable on any future variable.
 */
class DeferredCallChain implements \JsonSerializable, \ArrayAccess
{
    use \JClaveau\Traits\Fluent\New_;
    use FunctionCallTrait;
    
    /** @var array $stack The stack of deferred calls */
    protected $stack = [];

    /** @var mixed $expectedTarget The stack of deferred calls */
    protected $expectedTarget;

    /**
     * Constructor 
     * 
     * @param string $key The entry to acces
     */
    public function __construct($class_type_or_instance=null)
    {
        if ($class_type_or_instance) {
            $this->expectedTarget = $class_type_or_instance;
        }
    }

    /**
     * ArrayAccess interface
     *
     * @param string $key The entry to acces
     */
    public function &offsetGet($key)
    {
        $this->stack[] = [
            'entry' => $key,
        ];

        return $this;
    }

    /**
     * Stores any call in the the stack.
     *
     * @param  string $method
     * @param  array  $arguments
     *
     * @return $this
     */
    public final function __call($method, array $arguments)
    {
        $this->stack[] = [
            'method'    => $method,
            'arguments' => $arguments,
        ];

        return $this;
    }

    /**
     * For implementing JsonSerializable interface.
     *
     * @see https://secure.php.net/manual/en/jsonserializable.jsonserialize.php
     */
    public function jsonSerialize()
    {
        return $this->stack;
    }

    /**
     * Outputs the PHP code producing the current call chain while it's casted
     * as a string.
     *
     * @return string The PHP code corresponding to this call chain
     */
    public function __toString()
    {
        $string = '(new ' . get_called_class();
        if (is_string($this->expectedTarget)) {
            $string .= '(' . var_export($this->expectedTarget, true) . ')';
        }
        elseif (is_object($this->expectedTarget)) {
            $string .= '( ' . get_class($this->expectedTarget) . '#' . spl_object_id($this->expectedTarget) . ' )';
        }
        $string .= ')';

        foreach ($this->stack as $i => $call) {
            if (isset($call['method'])) {
                $string .= '->';
                $string .= $call['method'].'(';
                $string .= implode(', ', array_map(function($argument) {
                    return var_export($argument, true);
                }, $call['arguments']));
                $string .= ')';
            }
            else {
                $string .= '[' . var_export($call['entry'], true) . ']';
            }
        }

        return $string;
    }

    /**
     * Checks that the provided target matches the type/class/interface
     * given during construction.
     * 
     * @param  mixed $target
     * @return mixed $target Checked
     */
    protected function checkTarget($target)
    {
        if (is_object($this->expectedTarget)) {
            if ($target) {
                throw new TargetAlreadyDefinedException($this, $this->expectedTarget, $target);
            }
            
            $out = $this->expectedTarget;
        }
        elseif (is_string($this->expectedTarget)) {
            if (class_exists($this->expectedTarget)) {
                if (! $target instanceof $this->expectedTarget) {
                    throw new BadTargetClassException($this, $this->expectedTarget, $target);
                }
            }
            elseif (interface_exists($this->expectedTarget)) {
                if (! $target instanceof $this->expectedTarget) {
                    throw new BadTargetInterfaceException($this, $this->expectedTarget, $target);
                }
            }
            elseif (type_exists($this->expectedTarget)) {
                if (gettype($target) != $this->expectedTarget) {
                    throw new BadTargetTypeException($this, $this->expectedTarget, $target);
                }
            }
            else {
                throw new UndefinedTargetClassException($this, $this->expectedTarget);
            }
            
            $out = $target;
        }
        else {
            $out = $target;
        }
        
        return $out;
    }

    /**
     * Calling a method coded inside a magic __call can produce a 
     * BadMethodCallException and thus not be a callable.
     * 
     * @param mixed  $current_chained_subject
     * @param string $method_name
     * @param array  $arguments
     * 
     * @return bool $is_called
     */
    protected function checkMethodIsReallyCallable(
        &$current_chained_subject, 
        $method_name,
        $arguments
    ) {
        $is_called = true;
        try {
            $current_chained_subject = call_user_func_array(
                [$current_chained_subject, $method_name], 
                $arguments
            );
        }
        catch (\BadMethodCallException $e) {
            if ($this->exceptionTrownFromMagicCall(
                $e->getTrace(),
                $current_chained_subject,
                $method_name
            )) {
                $is_called = false;
            }
            else {
                throw $e;
            }
        }
        
        return $is_called;
    }

    /**
     * Checks if the exception having $trace is thrown from à __call
     * magic method.
     * 
     * @return bool $is_called
     */
    protected function exceptionTrownFromMagicCall(
        $trace, 
        $current_chained_subject,
        $method_name
    ) {
        $call_user_func_array_position = PHP_VERSION_ID < 70000 ? 2 : 1;
        
        return  $trace[0]['function'] == '__call'
            &&  $trace[0]['class'] == get_class($current_chained_subject)
            && (
                    $trace[$call_user_func_array_position]['file'] == __FILE__
                &&  $trace[$call_user_func_array_position]['function'] == 'call_user_func_array'
            )
            && (
                // The magic method call doesn't exist in the stack with PHP 7
                    PHP_VERSION_ID < 70000
                &&  $trace[1]['function'] == $method_name
                &&  $trace[1]['class'] == get_class($current_chained_subject)
            )
            ;
    }

    /**
     * Invoking the instance produces the call of the stack
     *
     * @param  mixed $target The target to apply the callchain on
     * @return mixde The value returned once the call chain is called uppon $target

The type JClaveau\Async\mixde was not found. Maybe you did not declare it correctly or list all dependencies?

     */
    public function __invoke($target=null)
    {
        $out = $this->checkTarget($target);
        
        foreach ($this->stack as $i => $call) {
            $is_called = false;
            try {
                if (isset($call['method'])) {
                    if (is_callable([$out, $call['method']])) {
                        $is_called = $this->checkMethodIsReallyCallable(
                            $out,
                            $call['method'],
                            $call['arguments']
                        );
                    }
                    
                    if (! $is_called && is_callable($call['method'])) {
                        $arguments = $this->prepareArgs($call['arguments'], $out);
                        $out = call_user_func_array($call['method'], $arguments);
                        $is_called = true;
                    }
                    
                    if (! $is_called) {
                        throw new \BadMethodCallException(
                            $call['method'] . "() is neither a method of " . get_class($out)
                            . " nor a function"
                        );
                    }
                }
                else {
                    $out = $out[ $call['entry'] ];
                }
            }
            catch (\Exception $e) {
                // Throw $e with the good stack (usage exception)
                throw $e;
            }
        }

        return $out;
    }

    /**
     * Unused part of the ArrayAccess interface
     *
     * @param  $offset
     * @param  $value
     * @throws \BadMethodCallException
     */
    public function offsetSet($offset, $value)
    {
        throw new BadMethodCallException(
            "not implemented"
        );
    }

    /**
     * Unused part of the ArrayAccess interface
     *
     * @param  $offset
     * @throws \BadMethodCallException
     */
    public function offsetExists($offset)
    {
        throw new BadMethodCallException(
            "not implemented"
        );
    }

    /**
     * Unused part of the ArrayAccess interface
     *
     * @param  $offset
     * @throws \BadMethodCallException
     */
    public function offsetUnset($offset)
    {
        throw new BadMethodCallException(
            "not implemented"
        );
    }

    /**/
}