Assemble the cache_id to use for a given block.
The cache_id string reflects the viewing context for the current block instance, obtained by concatenating the relevant context information (user, page, ...) according to the block's cache settings (BLOCK_CACHE_* constants). Two block instances can use the same cached content when they share the same cache_id.
Theme and language contexts are automatically differentiated.
$block: The block to get the cache_id from.
The string used as cache_id for the block.
function _block_get_cache_id($block) {
global $user;
// User 1 being out of the regular 'roles define permissions' schema,
// it brings too many chances of having unwanted output get in the cache
// and later be served to other users. We therefore exclude user 1 from
// block caching.
if (variable_get('block_cache', FALSE) && !in_array($block->cache, array(
DRUPAL_NO_CACHE,
DRUPAL_CACHE_CUSTOM,
)) && $user->uid != 1) {
// Start with common sub-patterns: block identification, theme, language.
$cid_parts[] = $block->module;
$cid_parts[] = $block->delta;
drupal_alter('block_cid_parts', $cid_parts, $block);
$cid_parts = array_merge($cid_parts, drupal_render_cid_parts($block->cache));
return implode(':', $cid_parts);
}
}