interface ContextProviderInterface

interface ContextProviderInterface {
    
    /**
     * Gets runtime context values for the given context IDs.
     *
     * For context-aware plugins to function correctly, all of the contexts that
     * they require must be populated with values. So this method should set a
     * value for each context that it adds. For example:
     *
     * @code
     *   // Determine a specific node to pass as context to a block.
     *   $node = ...
     *
     *   // Set that specific node as the value of the 'node' context.
     *   $context = EntityContext::fromEntity($node);
     *   return ['node' => $context];
     * @endcode
     *
     * On the other hand, there are cases, on which providers no longer are
     * possible to provide context objects, even without the value, so the caller
     * should not expect it.
     *
     * @param string[] $unqualified_context_ids
     *   The requested context IDs. The context provider must only return contexts
     *   for those IDs.
     *
     * @return \Drupal\Core\Plugin\Context\ContextInterface[]
     *   The determined available contexts, keyed by the unqualified context_id.
     *
     * @see \Drupal\Core\Plugin\Context\ContextProviderInterface:getAvailableContexts()
     */
    public function getRuntimeContexts(array $unqualified_context_ids);
    
    /**
     * Gets all available contexts for the purposes of configuration.
     *
     * When a context aware plugin is being configured, the configuration UI must
     * know which named contexts are potentially available, but does not care
     * about the value, since the value can be different for each request, and
     * might not be available at all during the configuration UI's request.
     *
     * For example:
     * @code
     *   // During configuration, there is no specific node to pass as context.
     *   // However, inform the system that a context named 'node' is
     *   // available, and provide its definition, so that context aware plugins
     *   // can be configured to use it. When the plugin, for example a block,
     *   // needs to evaluate the context, the value of this context will be
     *   // supplied by getRuntimeContexts().
     *   $context = EntityContext::fromEntityTypeId('node');
     *   return ['node' => $context];
     * @endcode
     *
     * @return \Drupal\Core\Plugin\Context\ContextInterface[]
     *   All available contexts keyed by the unqualified context ID.
     *
     * @see \Drupal\Core\Plugin\Context\ContextProviderInterface::getRuntimeContext()
     */
    public function getAvailableContexts();

}