Chris@0: <?php
Chris@0: 
Chris@0: namespace Drupal\Component\Utility;
Chris@0: 
Chris@0: /**
Chris@0:  * Resolves the arguments to pass to a callable.
Chris@0:  */
Chris@0: class ArgumentsResolver implements ArgumentsResolverInterface {
Chris@0: 
Chris@0:   /**
Chris@0:    * An associative array of parameter names to scalar candidate values.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $scalars;
Chris@0: 
Chris@0:   /**
Chris@0:    * An associative array of parameter names to object candidate values.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $objects;
Chris@0: 
Chris@0:   /**
Chris@0:    * An array object candidates tried on every parameter regardless of name.
Chris@0:    *
Chris@0:    * @var array
Chris@0:    */
Chris@0:   protected $wildcards;
Chris@0: 
Chris@0:   /**
Chris@0:    * Constructs a new ArgumentsResolver.
Chris@0:    *
Chris@0:    * @param array $scalars
Chris@0:    *   An associative array of parameter names to scalar candidate values.
Chris@0:    * @param object[] $objects
Chris@0:    *   An associative array of parameter names to object candidate values.
Chris@0:    * @param object[] $wildcards
Chris@0:    *   An array object candidates tried on every parameter regardless of its
Chris@0:    *   name.
Chris@0:    */
Chris@0:   public function __construct(array $scalars, array $objects, array $wildcards) {
Chris@0:     $this->scalars = $scalars;
Chris@0:     $this->objects = $objects;
Chris@0:     $this->wildcards = $wildcards;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * {@inheritdoc}
Chris@0:    */
Chris@0:   public function getArguments(callable $callable) {
Chris@0:     $arguments = [];
Chris@0:     foreach ($this->getReflector($callable)->getParameters() as $parameter) {
Chris@0:       $arguments[] = $this->getArgument($parameter);
Chris@0:     }
Chris@0:     return $arguments;
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets the argument value for a parameter.
Chris@0:    *
Chris@0:    * @param \ReflectionParameter $parameter
Chris@0:    *   The parameter of a callable to get the value for.
Chris@0:    *
Chris@0:    * @return mixed
Chris@0:    *   The value of the requested parameter value.
Chris@0:    *
Chris@0:    * @throws \RuntimeException
Chris@0:    *   Thrown when there is a missing parameter.
Chris@0:    */
Chris@0:   protected function getArgument(\ReflectionParameter $parameter) {
Chris@0:     $parameter_type_hint = $parameter->getClass();
Chris@0:     $parameter_name = $parameter->getName();
Chris@0: 
Chris@0:     // If the argument exists and is NULL, return it, regardless of
Chris@0:     // parameter type hint.
Chris@0:     if (!isset($this->objects[$parameter_name]) && array_key_exists($parameter_name, $this->objects)) {
Chris@0:       return NULL;
Chris@0:     }
Chris@0: 
Chris@0:     if ($parameter_type_hint) {
Chris@0:       // If the argument exists and complies with the type hint, return it.
Chris@0:       if (isset($this->objects[$parameter_name]) && is_object($this->objects[$parameter_name]) && $parameter_type_hint->isInstance($this->objects[$parameter_name])) {
Chris@0:         return $this->objects[$parameter_name];
Chris@0:       }
Chris@0:       // Otherwise, resolve wildcard arguments by type matching.
Chris@0:       foreach ($this->wildcards as $wildcard) {
Chris@0:         if ($parameter_type_hint->isInstance($wildcard)) {
Chris@0:           return $wildcard;
Chris@0:         }
Chris@0:       }
Chris@0:     }
Chris@0:     elseif (isset($this->scalars[$parameter_name])) {
Chris@0:       return $this->scalars[$parameter_name];
Chris@0:     }
Chris@0: 
Chris@0:     // If the callable provides a default value, use it.
Chris@0:     if ($parameter->isDefaultValueAvailable()) {
Chris@0:       return $parameter->getDefaultValue();
Chris@0:     }
Chris@0: 
Chris@0:     // Can't resolve it: call a method that throws an exception or can be
Chris@0:     // overridden to do something else.
Chris@0:     return $this->handleUnresolvedArgument($parameter);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Gets a reflector for the access check callable.
Chris@0:    *
Chris@0:    * The access checker may be either a procedural function (in which case the
Chris@0:    * callable is the function name) or a method (in which case the callable is
Chris@0:    * an array of the object and method name).
Chris@0:    *
Chris@0:    * @param callable $callable
Chris@0:    *   The callable (either a function or a method).
Chris@0:    *
Chris@0:    * @return \ReflectionFunctionAbstract
Chris@0:    *   The ReflectionMethod or ReflectionFunction to introspect the callable.
Chris@0:    */
Chris@0:   protected function getReflector(callable $callable) {
Chris@0:     return is_array($callable) ? new \ReflectionMethod($callable[0], $callable[1]) : new \ReflectionFunction($callable);
Chris@0:   }
Chris@0: 
Chris@0:   /**
Chris@0:    * Handles unresolved arguments for getArgument().
Chris@0:    *
Chris@0:    * Subclasses that override this method may return a default value
Chris@0:    * instead of throwing an exception.
Chris@0:    *
Chris@0:    * @throws \RuntimeException
Chris@0:    *   Thrown when there is a missing parameter.
Chris@0:    */
Chris@0:   protected function handleUnresolvedArgument(\ReflectionParameter $parameter) {
Chris@0:     $class = $parameter->getDeclaringClass();
Chris@0:     $function = $parameter->getDeclaringFunction();
Chris@0:     if ($class && !$function->isClosure()) {
Chris@0:       $function_name = $class->getName() . '::' . $function->getName();
Chris@0:     }
Chris@0:     else {
Chris@0:       $function_name = $function->getName();
Chris@0:     }
Chris@0:     throw new \RuntimeException(sprintf('Callable "%s" requires a value for the "$%s" argument.', $function_name, $parameter->getName()));
Chris@0:   }
Chris@0: 
Chris@0: }