diff core/modules/jsonapi/src/JsonApiResource/LinkCollection.php @ 18:af1871eacc83

Update to Drupal core 8.7.1

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/core/modules/jsonapi/src/JsonApiResource/LinkCollection.php	Thu May 09 15:33:08 2019 +0100
@@ -0,0 +1,199 @@
+<?php
+
+namespace Drupal\jsonapi\JsonApiResource;
+
+use Drupal\Component\Assertion\Inspector;
+
+/**
+ * Contains a set of JSON:API Link objects.
+ *
+ * @internal JSON:API maintains no PHP API. The API is the HTTP API. This class
+ *   may change at any time and could break any dependencies on it.
+ *
+ * @see https://www.drupal.org/project/jsonapi/issues/3032787
+ * @see jsonapi.api.php
+ */
+final class LinkCollection implements \IteratorAggregate {
+
+  /**
+   * The links in the collection, keyed by unique strings.
+   *
+   * @var \Drupal\jsonapi\JsonApiResource\Link[]
+   */
+  protected $links;
+
+  /**
+   * The link context.
+   *
+   * All links objects exist within a context object. Links form a relationship
+   * between a source IRI and target IRI. A context is the link's source.
+   *
+   * @var \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel|\Drupal\jsonapi\JsonApiResource\ResourceObject
+   *
+   * @see https://tools.ietf.org/html/rfc8288#section-3.2
+   */
+  protected $context;
+
+  /**
+   * LinkCollection constructor.
+   *
+   * @param \Drupal\jsonapi\JsonApiResource\Link[] $links
+   *   An associated array of key names and JSON:API Link objects.
+   * @param \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel|\Drupal\jsonapi\JsonApiResource\ResourceObject $context
+   *   (internal use only) The context object. Use the self::withContext()
+   *   method to establish a context. This should be done automatically when
+   *   a LinkCollection is passed into a context object.
+   */
+  public function __construct(array $links, $context = NULL) {
+    assert(Inspector::assertAll(function ($key) {
+      return static::validKey($key);
+    }, array_keys($links)));
+    assert(Inspector::assertAll(function ($link) {
+      return $link instanceof Link || is_array($link) && Inspector::assertAllObjects($link, Link::class);
+    }, $links));
+    assert(is_null($context) || Inspector::assertAllObjects([$context], JsonApiDocumentTopLevel::class, ResourceObject::class));
+    ksort($links);
+    $this->links = array_map(function ($link) {
+      return is_array($link) ? $link : [$link];
+    }, $links);
+    $this->context = $context;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function getIterator() {
+    assert(!is_null($this->context), 'A LinkCollection is invalid unless a context has been established.');
+    return new \ArrayIterator($this->links);
+  }
+
+  /**
+   * Gets a new LinkCollection with the given link inserted.
+   *
+   * @param string $key
+   *   A key for the link. If the key already exists and the link shares an href
+   *   with an existing link with that key, those links will be merged together.
+   * @param \Drupal\jsonapi\JsonApiResource\Link $new_link
+   *   The link to insert.
+   *
+   * @return static
+   *   A new LinkCollection with the given link inserted or merged with the
+   *   current set of links.
+   */
+  public function withLink($key, Link $new_link) {
+    assert(static::validKey($key));
+    $merged = $this->links;
+    if (isset($merged[$key])) {
+      foreach ($merged[$key] as $index => $existing_link) {
+        if (Link::compare($existing_link, $new_link) === 0) {
+          $merged[$key][$index] = Link::merge($existing_link, $new_link);
+          return new static($merged, $this->context);
+        }
+      }
+    }
+    $merged[$key][] = $new_link;
+    return new static($merged, $this->context);
+  }
+
+  /**
+   * Whether a link with the given key exists.
+   *
+   * @param string $key
+   *   The key.
+   *
+   * @return bool
+   *   TRUE if a link with the given key exist, FALSE otherwise.
+   */
+  public function hasLinkWithKey($key) {
+    return array_key_exists($key, $this->links);
+  }
+
+  /**
+   * Establishes a new context for a LinkCollection.
+   *
+   * @param \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel|\Drupal\jsonapi\JsonApiResource\ResourceObject $context
+   *   The new context object.
+   *
+   * @return static
+   *   A new LinkCollection with the given context.
+   */
+  public function withContext($context) {
+    return new static($this->links, $context);
+  }
+
+  /**
+   * Gets the LinkCollection's context object.
+   *
+   * @return \Drupal\jsonapi\JsonApiResource\JsonApiDocumentTopLevel|\Drupal\jsonapi\JsonApiResource\ResourceObject
+   *   The LinkCollection's context.
+   */
+  public function getContext() {
+    assert(!is_null($this->context), 'A LinkCollection is invalid unless a context has been established.');
+    return $this->context;
+  }
+
+  /**
+   * Filters a LinkCollection using the provided callback.
+   *
+   * @param callable $f
+   *   The filter callback. The callback has the signature below.
+   *
+   * @code
+   *   boolean callback(string $key, \Drupal\jsonapi\JsonApiResource\Link $link, mixed $context))
+   * @endcode
+   *
+   * @return \Drupal\jsonapi\JsonApiResource\LinkCollection
+   *   A new, filtered LinkCollection.
+   */
+  public function filter(callable $f) {
+    $links = iterator_to_array($this);
+    $filtered = array_reduce(array_keys($links), function ($filtered, $key) use ($links, $f) {
+      if ($f($key, $links[$key], $this->context)) {
+        $filtered[$key] = $links[$key];
+      }
+      return $filtered;
+    }, []);
+    return new LinkCollection($filtered, $this->context);
+  }
+
+  /**
+   * Merges two LinkCollections.
+   *
+   * @param \Drupal\jsonapi\JsonApiResource\LinkCollection $a
+   *   The first link collection.
+   * @param \Drupal\jsonapi\JsonApiResource\LinkCollection $b
+   *   The second link collection.
+   *
+   * @return \Drupal\jsonapi\JsonApiResource\LinkCollection
+   *   A new LinkCollection with the links of both inputs.
+   */
+  public static function merge(LinkCollection $a, LinkCollection $b) {
+    assert($a->getContext() === $b->getContext());
+    $merged = new LinkCollection([], $a->getContext());
+    foreach ($a as $key => $links) {
+      $merged = array_reduce($links, function (self $merged, Link $link) use ($key) {
+        return $merged->withLink($key, $link);
+      }, $merged);
+    }
+    foreach ($b as $key => $links) {
+      $merged = array_reduce($links, function (self $merged, Link $link) use ($key) {
+        return $merged->withLink($key, $link);
+      }, $merged);
+    }
+    return $merged;
+  }
+
+  /**
+   * Ensures that a link key is valid.
+   *
+   * @param string $key
+   *   A key name.
+   *
+   * @return bool
+   *   TRUE if the key is valid, FALSE otherwise.
+   */
+  protected static function validKey($key) {
+    return is_string($key) && !is_numeric($key) && strpos($key, ':') === FALSE;
+  }
+
+}