book_blocks-8.x-1.4/book_blocks.module

<?php

/**
 * @file
 * Allows users to create and organize related content in an outline.
 */

use Drupal\Core\Routing\RouteMatchInterface;
use Drupal\Core\Url;

/**
 * Implements hook_help().
 */
function book_blocks_help($route_name, RouteMatchInterface $route_match) {
  switch ($route_name) {
    case 'help.page.book_blocks':
      $output = '';
      $output .= '<h2>' . t('Module description') . '</h2>';
      $output .= '<p>' . t('The built-in Book module has a couple of useful
        blocks including a list of children (Children), navigation,
        Table of Contents (includes a link to the top page),
        and Edit (combination of navigation, TOC and edit links).') . '</p>';
      return $output;

    break;
  }
}

/**
 * Implements hook_theme().
 */
function book_blocks_theme() {
  return [
    'book_blocks_navigation' => [
      'variables' => ['book_link' => NULL],
    ],
    'book_blocks_edit' => [
      'variables' => [
        'book_link' => NULL,
        'css' => '',
        'toc' => FALSE,
        'nav' => FALSE,
        'icons' => FALSE,
        'left_link' => NULL,
        'middle_link' => NULL,
        'right_link' => NULL,
        'sibling_link' => NULL,
        'child_link' => NULL,
        'print_link' => NULL,
        'my_element_id' => NULL,
        'module_path' => base_path() . \Drupal::service('module_handler')->getModule('book_blocks')->getPath(),
      ],
    ],
    'book_blocks_children' => [
      'variables' => ['book_link' => NULL],
    ],
  ];
}

/**
 * Get URL String from nid.
 *
 * @param int $nid
 *
 * @return string
 */
function _book_block_url($nid) {
  return Url::fromRoute('entity.node.canonical', ['node' => $nid])->toString();
}

/**
 * Prepares variables for book_blocks templates.
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_link: An associative array of book link properties.
 *     Properties used: bid, link_title, depth, pid, nid.
 */
function _template_preprocess_book_blocks(&$variables) {
  $book_link = $variables['book_link'];

  // Provide extra variables for themers. Not needed by default.
  $variables['book_id'] = $book_link['bid'];
  $variables['book_title'] = $book_link['title'];
  $variables['book_url'] = _book_block_url($book_link['bid']);
  $variables['current_depth'] = $book_link['depth'];
  $variables['tree'] = '';

  /** @var \Drupal\book\BookOutline $book_outline */
  $book_outline = \Drupal::service('book.outline');

  if ($book_link['nid']) {
    $build = [];

    if ($prev = $book_outline->prevLink($book_link)) {
      $prev_href = _book_block_url($prev['nid']);
      $build['#attached']['html_head_link'][][] = [
        'rel' => 'prev',
        'href' => $prev_href,
      ];
      $variables['prev_url'] = $prev_href;
      $variables['prev_title'] = $prev['title'];
    }

    /** @var \Drupal\book\BookManagerInterface $book_manager */
    $book_manager = \Drupal::service('book.manager');
    if ($book_link['pid'] && $parent = $book_manager->loadBookLink($book_link['pid'])) {
      $parent_href = _book_block_url($book_link['pid']);
      $build['#attached']['html_head_link'][][] = [
        'rel' => 'up',
        'href' => $parent_href,
      ];
      $variables['parent_url'] = $parent_href;
      $variables['parent_title'] = $parent['title'];
    }

    if ($next = $book_outline->nextLink($book_link)) {
      $next_href = _book_block_url($next['nid']);
      $build['#attached']['html_head_link'][][] = [
        'rel' => 'next',
        'href' => $next_href,
      ];
      $variables['next_url'] = $next_href;
      $variables['next_title'] = $next['title'];
    }
  }

  if (!empty($build)) {
    \Drupal::service('renderer')->render($build);
  }

  $variables['has_links'] = FALSE;
  // Link variables to filter for values and set state of the flag variable.
  $links = ['prev_url', 'prev_title', 'parent_url', 'parent_title', 'next_url', 'next_title'];
  foreach ($links as $link) {
    if (isset($variables[$link])) {
      // Flag when there is a value.
      $variables['has_links'] = TRUE;
    }
    else {
      // Set empty to prevent notices.
      $variables[$link] = '';
    }
  }
}

/**
 * Prepares variables for book navigation templates.
 *
 * Default template: book-blocks-navigation.html.twig.
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_link: An associative array of book link properties.
 *     Properties used: bid, link_title, depth, pid, nid.
 */
function template_preprocess_book_blocks_navigation(&$variables) {
  _template_preprocess_book_blocks($variables);
}

/**
 * Prepares variables for book navigation templates.
 *
 * Default template: book-blocks-edit.html.twig.
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_link: An associative array of book link properties.
 *     Properties used: bid, link_title, depth, pid, nid.
 */
function template_preprocess_book_blocks_edit(&$variables) {
  _template_preprocess_book_blocks($variables);
}

/**
 * Prepares variables for book navigation templates.
 *
 * Default template: book-blocks-children.html.twig.
 *
 * @param array $variables
 *   An associative array containing the following key:
 *   - book_link: An associative array of book link properties.
 *     Properties used: bid, link_title, depth, pid, nid.
 */
function template_preprocess_book_blocks_children(&$variables) {
  _template_preprocess_book_blocks($variables);

  $book_outline = \Drupal::service('book.outline');
  $variables['tree'] = $book_outline->childrenLinks($variables['book_link']);
}