function drupal_render_cid_parts

Returns cache ID parts for building a cache ID.

Parameters

$granularity: One or more cache granularity constants. For example, to cache separately for each user, use DRUPAL_CACHE_PER_USER. To cache separately for each page and role, use the expression:

DRUPAL_CACHE_PER_PAGE | DRUPAL_CACHE_PER_ROLE;

Return value

An array of cache ID parts, always containing the active theme. If the locale module is enabled it also contains the active language. If $granularity was passed in, more parts are added.

File

includes/common.inc, line 6552

Code

function drupal_render_cid_parts($granularity = NULL) {
    global $theme, $base_root, $user;
    $cid_parts[] = $theme;
    // If Locale is enabled but we have only one language we do not need it as cid
    // part.
    if (drupal_multilingual()) {
        foreach (language_types_configurable() as $language_type) {
            $cid_parts[] = $GLOBALS[$language_type]->language;
        }
    }
    if (!empty($granularity)) {
        $cache_per_role = $granularity & DRUPAL_CACHE_PER_ROLE;
        $cache_per_user = $granularity & DRUPAL_CACHE_PER_USER;
        // User 1 has special permissions outside of the role system, so when
        // caching per role is requested, it should cache per user instead.
        if ($user->uid == 1 && $cache_per_role) {
            $cache_per_user = TRUE;
            $cache_per_role = FALSE;
        }
        // 'PER_ROLE' and 'PER_USER' are mutually exclusive. 'PER_USER' can be a
        // resource drag for sites with many users, so when a module is being
        // equivocal, we favor the less expensive 'PER_ROLE' pattern.
        if ($cache_per_role) {
            $cid_parts[] = 'r.' . implode(',', array_keys($user->roles));
        }
        elseif ($cache_per_user) {
            $cid_parts[] = "u.{$user->uid}";
        }
        if ($granularity & DRUPAL_CACHE_PER_PAGE) {
            $cid_parts[] = $base_root . request_uri();
        }
    }
    return $cid_parts;
}