Implements \Drupal\Core\Extension\ModuleHandlerInterface::alter().
Overrides ModuleHandlerInterface::alter
public function alter($type, &$data, &$context1 = NULL, &$context2 = NULL) {
// Most of the time, $type is passed as a string, so for performance,
// normalize it to that. When passed as an array, usually the first item in
// the array is a generic type, and additional items in the array are more
// specific variants of it, as in the case of array('form', 'form_FORM_ID').
if (is_array($type)) {
$cid = implode(',', $type);
$extra_types = $type;
$type = array_shift($extra_types);
// Allow if statements in this function to use the faster isset() rather
// than !empty() both when $type is passed as a string, or as an array with
// one item.
if (empty($extra_types)) {
unset($extra_types);
}
}
else {
$cid = $type;
}
// Some alter hooks are invoked many times per page request, so store the
// list of functions to call, and on subsequent calls, iterate through them
// quickly.
if (!isset($this->alterFunctions[$cid])) {
$this->alterFunctions[$cid] = array();
$hook = $type . '_alter';
$modules = $this
->getImplementations($hook);
if (!isset($extra_types)) {
// For the more common case of a single hook, we do not need to call
// function_exists(), since $this->getImplementations() returns only modules with
// implementations.
foreach ($modules as $module) {
$this->alterFunctions[$cid][] = $module . '_' . $hook;
}
}
else {
// For multiple hooks, we need $modules to contain every module that
// implements at least one of them.
$extra_modules = array();
foreach ($extra_types as $extra_type) {
$extra_modules = array_merge($extra_modules, $this
->getImplementations($extra_type . '_alter'));
}
// If any modules implement one of the extra hooks that do not implement
// the primary hook, we need to add them to the $modules array in their
// appropriate order. $this->getImplementations() can only return ordered
// implementations of a single hook. To get the ordered implementations
// of multiple hooks, we mimic the $this->getImplementations() logic of first
// ordering by $this->getModuleList(), and then calling
// $this->alter('module_implements').
if (array_diff($extra_modules, $modules)) {
// Merge the arrays and order by getModuleList().
$modules = array_intersect(array_keys($this->moduleList), array_merge($modules, $extra_modules));
// Since $this->getImplementations() already took care of loading the necessary
// include files, we can safely pass FALSE for the array values.
$implementations = array_fill_keys($modules, FALSE);
// Let modules adjust the order solely based on the primary hook. This
// ensures the same module order regardless of whether this if block
// runs. Calling $this->alter() recursively in this way does not result
// in an infinite loop, because this call is for a single $type, so we
// won't end up in this code block again.
$this
->alter('module_implements', $implementations, $hook);
$modules = array_keys($implementations);
}
foreach ($modules as $module) {
// Since $modules is a merged array, for any given module, we do not
// know whether it has any particular implementation, so we need a
// function_exists().
$function = $module . '_' . $hook;
if (function_exists($function)) {
$this->alterFunctions[$cid][] = $function;
}
foreach ($extra_types as $extra_type) {
$function = $module . '_' . $extra_type . '_alter';
if (function_exists($function)) {
$this->alterFunctions[$cid][] = $function;
}
}
}
}
// Allow the theme to alter variables after the theme system has been
// initialized.
global $theme, $base_theme_info;
if (isset($theme)) {
$theme_keys = array();
foreach ($base_theme_info as $base) {
$theme_keys[] = $base->name;
}
$theme_keys[] = $theme;
foreach ($theme_keys as $theme_key) {
$function = $theme_key . '_' . $hook;
if (function_exists($function)) {
$this->alterFunctions[$cid][] = $function;
}
if (isset($extra_types)) {
foreach ($extra_types as $extra_type) {
$function = $theme_key . '_' . $extra_type . '_alter';
if (function_exists($function)) {
$this->alterFunctions[$cid][] = $function;
}
}
}
}
}
}
foreach ($this->alterFunctions[$cid] as $function) {
$function($data, $context1, $context2);
}
}