NodeRevisionAccessCheck::checkAccess

public NodeRevisionAccessCheck::checkAccess(NodeInterface $node, AccountInterface $account, $op = 'view')

public function checkAccess(NodeInterface $node, AccountInterface $account, $op = 'view') {
  $map = array(
    'view' => 'view all revisions',
    'update' => 'revert all revisions',
    'delete' => 'delete all revisions',
  );
  $bundle = $node->bundle();
  $type_map = array(
    'view' => "view $bundle revisions",
    'update' => "revert $bundle revisions",
    'delete' => "delete $bundle revisions",
  );

  if (!$node || !isset($map[$op]) || !isset($type_map[$op])) {
    // If there was no node to check against, or the $op was not one of the
    // supported ones, we return access denied.
    return FALSE;
  }

  // Statically cache access by revision ID, language code, user account ID,
  // and operation.
  $langcode = $node->language()->getId();
  $cid = $node->getRevisionId() . ':' . $langcode . ':' . $account->id() . ':' . $op;

  if (!isset($this->access[$cid])) {
    // Perform basic permission checks first.
    if (!$account->hasPermission($map[$op]) && !$account->hasPermission($type_map[$op]) && !$account->hasPermission('administer nodes')) {
      $this->access[$cid] = FALSE;
      return FALSE;
    }

    // There should be at least two revisions. If the vid of the given node
    // and the vid of the default revision differ, then we already have two
    // different revisions so there is no need for a separate database check.
    // Also, if you try to revert to or delete the default revision, that's
    // not good.
    if ($node->isDefaultRevision() && ($this->nodeStorage->countDefaultLanguageRevisions($node) == 1 || $op == 'update' || $op == 'delete')) {
      $this->access[$cid] = FALSE;
    }
    elseif ($account->hasPermission('administer nodes')) {
      $this->access[$cid] = TRUE;
    }
    else {
      // First check the access to the default revision and finally, if the
      // node passed in is not the default revision then access to that, too.
      $this->access[$cid] = $this->nodeAccess->access($this->nodeStorage->load($node->id()), $op, $account) && ($node->isDefaultRevision() || $this->nodeAccess->access($node, $op, $account));
    }
  }

  return $this->access[$cid];
}