materio-base-d7/sites/all/modules/contrib/seo/metatag/metatag_favicons/metatag_favicons.module

<?php

/**
 * @file
 * Primary hook implementations for Metatag:favicons.
 */

/**
 * Implements hook_ctools_plugin_api().
 */
function metatag_favicons_ctools_plugin_api($owner, $api) {
  if ($owner == 'metatag' && $api == 'metatag') {
    return array('version' => 1);
  }
}

/**
 * Implements hook_theme().
 */
function metatag_favicons_theme() {
  $info['metatag_favicon'] = array(
    'render element' => 'element',
  );

  $info['metatag_mask_icon'] = array(
    'render element' => 'element',
  );

  $info['metatag_shortcut_icon'] = array(
    'render element' => 'element',
  );
  return $info;
}

/**
 * Implements hoko_html_head_alter().
 *
 * Remove the default shortcut icon if one was set by Metatag.
 */
function metatag_favicons_html_head_alter(&$elements) {
  if (isset($elements['metatag_shortcut icon'])) {
    foreach ($elements as $key => $element) {
      if (isset($element['#tag']) && $element['#tag'] == 'link') {
        if (isset($element['#attributes']) && is_array($element['#attributes'])) {
          if (isset($element['#attributes']['rel'])) {
            if ($element['#attributes']['rel'] == 'shortcut icon') {
              unset($elements[$key]);
            }
          }
        }
      }
    }
  }
}

/**
 * Theme callback for a favicon meta tag.
 *
 * The format is:
 * <link rel="[rel]" href="[value]" sizes="[sizes]" />
 */
function theme_metatag_favicon($variables) {
  $element = &$variables['element'];
  $args = array(
    '#rel' => 'rel',
    '#value' => 'href',
    '#sizes' => 'sizes',
    '#mask' => 'mask',
  );
  element_set_attributes($element, $args);
  unset($element['#value']);
  return theme('html_tag', $variables);
}

/**
 * Theme callback for the mask-icon meta tag.
 *
 * The format is:
 * <link rel="mask-icon" href="[value]" sizes="[sizes]" />
 */
function theme_metatag_mask_icon($variables) {
  $element = &$variables['element'];

  $args = array(
    '#rel' => 'rel',
    '#value' => 'href',
    '#color' => 'color',
  );
  element_set_attributes($element, $args);
  unset($element['#value']);
  return theme('html_tag', $variables);
}

/**
 * Theme callback for a shortcut icon meta tag.
 *
 * The format is:
 * <link rel="[rel]" href="[value]" type="[type]" />
 */
function theme_metatag_shortcut_icon($variables) {
  $element = &$variables['element'];

  // Extract the MIME type.
  $element['#type'] = metatag_favicons_get_mime_type($element['#value']);

  $args = array(
    '#rel' => 'rel',
    '#value' => 'href',
    '#type' => 'type',
  );
  element_set_attributes($element, $args);
  unset($element['#value']);
  return theme('html_tag', $variables);
}

/**
 * Helper function to get the theme's favicon URL.
 *
 * @return string
 *  The absolute URL to the favicon, empty string if not found.
 */
function metatag_favicons_get_theme_favicon() {
  $favicon_url = '';

  // Is the favicon enabled?
  if (theme_get_setting('toggle_favicon')) {
    $favicon_url = theme_get_setting('favicon');
  }

  return $favicon_url;
}

/**
 * Returns the correct MIME type for favicons.
 *
 * @param string $uri
 *   The URI, or URL, of the favicon to be checked.
 *
 * @return string
 *  The MIME type on success, an empty string on failure.
 */
function metatag_favicons_get_mime_type($uri) {
  // URLs must have a file extension in order for this to work.
  $extension_dot = strrpos($uri, '.');
  if (!$extension_dot) {
    return '';
  }
  // Return the proper MIME type based on the extension.
  $extension = strtolower(substr($uri, $extension_dot + 1));
  switch ($extension) {
    case 'ico':
      return 'image/vnd.microsoft.icon';

    case 'jpg':
    case 'jpeg':
      return 'image/jpeg';

    case 'svg':
      return 'image/svg+xml';

    case 'gif':
    case 'png':
      return 'image/' . $extension;

    default:
      return '';
  }
}