interface ContextHandlerInterface

interface ContextHandlerInterface {
    
    /**
     * Determines plugins whose constraints are satisfied by a set of contexts.
     *
     * @todo Use context definition objects after
     *   https://www.drupal.org/node/2281635.
     *
     * @param \Drupal\Component\Plugin\Context\ContextInterface[] $contexts
     *   An array of contexts.
     * @param array $definitions
     *   An array of plugin definitions.
     *
     * @return array
     *   An array of plugin definitions.
     */
    public function filterPluginDefinitionsByContexts(array $contexts, array $definitions);
    
    /**
     * Checks a set of requirements against a set of contexts.
     *
     * @todo Use context definition objects after
     *   https://www.drupal.org/node/2281635.
     *
     * @param \Drupal\Component\Plugin\Context\ContextInterface[] $contexts
     *   An array of available contexts.
     * @param \Drupal\Core\TypedData\DataDefinitionInterface[] $requirements
     *   An array of requirements.
     *
     * @return bool
     *   TRUE if all of the requirements are satisfied by the context, FALSE
     *   otherwise.
     */
    public function checkRequirements(array $contexts, array $requirements);
    
    /**
     * Determines which contexts satisfy the constraints of a given definition.
     *
     * @todo Use context definition objects after
     *   https://www.drupal.org/node/2281635.
     *
     * @param \Drupal\Component\Plugin\Context\ContextInterface[] $contexts
     *   An array of contexts.
     * @param \Drupal\Core\Plugin\Context\ContextDefinitionInterface $definition
     *   The definition to satisfy.
     *
     * @return \Drupal\Component\Plugin\Context\ContextInterface[]
     *   An array of matching contexts.
     */
    public function getMatchingContexts(array $contexts, ContextDefinitionInterface $definition);
    
    /**
     * Prepares a plugin for evaluation.
     *
     * @param \Drupal\Core\Plugin\ContextAwarePluginInterface $plugin
     *   A plugin about to be evaluated.
     * @param \Drupal\Core\Plugin\Context\ContextInterface[] $contexts
     *   An array of contexts to set on the plugin. They will only be set if they
     *   match the plugin's context definitions.
     * @param array $mappings
     *   (optional) A mapping of the expected assignment names to their context
     *   names. For example, if one of the $contexts is named 'current_user', but the
     *   plugin expects a context named 'user', then this map would contain
     *   'user' => 'current_user'.
     *
     * @throws \Drupal\Component\Plugin\Exception\ContextException
     *   Thrown when a context assignment was not satisfied.
     * @throws \Drupal\Component\Plugin\Exception\MissingValueContextException
     *   Thrown when a context is provided but has no value. Only thrown if
     *   no contexts are missing.
     */
    public function applyContextMapping(ContextAwarePluginInterface $plugin, $contexts, $mappings = []);

}