Disables a text format.
There is no core facility to re-enable a disabled format. It is not deleted to keep information for contrib and to make sure the format ID is never reused. As there might be content using the disabled format, this would lead to data corruption.
$format: The text format object to be disabled.
function filter_format_disable($format) {
db_update('filter_format')
->fields(array(
'status' => 0,
))
->condition('format', $format->format)
->execute();
// Allow modules to react on text format deletion.
module_invoke_all('filter_format_disable', $format);
// Clear the filter cache whenever a text format is disabled.
filter_formats_reset();
cache_clear_all($format->format . ':', 'cache_filter', TRUE);
}