drupal_alter
Definition
drupal_alter($type, &$data)
drupal/includes/common.inc, line 3143
Description
Hands off structured Drupal arrays to type-specific *_alter implementations.
This dispatch function hands off structured Drupal arrays to type-specific *_alter implementations. It ensures a consistent interface for all altering operations.
Parameters
$type The data type of the structured array. 'form', 'links', 'node_content', and so on are several examples.
$data The structured array to be altered.
... Any additional params will be passed on to the called hook_$type_alter functions.
Related topics
Name | Description |
|---|---|
| Input validation | Functions to validate user input. |
Code
function drupal_alter($type, &$data) {
// PHP's func_get_args() always returns copies of params, not references, so
// drupal_alter() can only manipulate data that comes in via the required first
// param. For the edge case functions that must pass in an arbitrary number of
// alterable parameters (hook_form_alter() being the best example), an array of
// those params can be placed in the __drupal_alter_by_ref key of the $data
// array. This is somewhat ugly, but is an unavoidable consequence of a flexible
// drupal_alter() function, and the limitations of func_get_args().
// @todo: Remove this in Drupal 7.
if (is_array($data) && isset($data['__drupal_alter_by_ref'])) {
$by_ref_parameters = $data['__drupal_alter_by_ref'];
unset($data['__drupal_alter_by_ref']);
}
// Hang onto a reference to the data array so that it isn't blown away later.
// Also, merge in any parameters that need to be passed by reference.
$args = array(&$data);
if (isset($by_ref_parameters)) {
$args = array_merge($args, $by_ref_parameters);
}
// Now, use func_get_args() to pull in any additional parameters passed into
// the drupal_alter() call.
$additional_args = func_get_args();
array_shift($additional_args);
array_shift($additional_args);
$args = array_merge($args, $additional_args);
foreach (module_implements($type . '_alter') as $module) {
$function = $module . '_' . $type . '_alter';
call_user_func_array($function, $args);
}
}