<?php

/**
 * @file
 * Provides breadcrumbs as configurable blocks.
 */

/**
 * Implements MODULE_preprocess_HOOK().
 */
function breadcrumb_preprocess_page(&$variables) {
  // Preemptively set the 'breadcrumb' variable, so that template_process_page()
  // performs nothing, and this module can render the breadcrumb as a block
  // instead.
  $variables['breadcrumb'] = '';
}

/**
 * Implements hook_block_list().
 */
function breadcrumb_block_info() {
  $blocks['breadcrumb'] = array(
    'info' => t('Breadcrumb'),
  );
  return $blocks;
}

/**
 * Implements hook_block_view().
 */
function breadcrumb_block_view($delta) {
  $block = array();
  if ($delta == 'breadcrumb') {
    // Use a #pre_render callback instead of theme() or drupal_get_breadcrumb(),
    // so breadcrumb building/retrieval happens similarly late as
    // template_process_page(), and thus, accounts for potential customizations.
    $block['content'] = array(
      '#pre_render' => array('breadcrumb_pre_render_breadcrumb'),
      '#theme' => 'breadcrumb',
    );
  }
  return $block;
}

/**
 * #pre_render callback for #theme 'breadcrumb' elements.
 */
function breadcrumb_pre_render_breadcrumb($element) {
  $element['#breadcrumb'] = drupal_get_breadcrumb();
  return $element;
}