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wp_find_hierarchy_loop_tortoise_hare() WP 3.1.0

Use the "The Tortoise and the Hare" algorithm to detect loops.

For every step of the algorithm, the hare takes two steps and the tortoise one. If the hare ever laps the tortoise, there must be a loop.

Хуков нет.

Возвращает

Разное. Scalar ID of some arbitrary member of the loop, or array of IDs of all members of loop if $_return_loop

Использование

wp_find_hierarchy_loop_tortoise_hare( $callback, $start, $override, $callback_args, $_return_loop );
$callback(callable) (обязательный)
Function that accepts ( ID, callback_arg, ... ) and outputs parent_ID.
$start(число) (обязательный)
The ID to start the loop check at.
$override(массив)
An array of ( ID => parent_ID, ... ) to use instead of $callback.
По умолчанию: empty array
$callback_args(массив)
Additional arguments to send to $callback.
По умолчанию: empty array
$_return_loop(true/false)
Return loop members or just detect presence of loop? Only set to true if you already know the given $start is part of a loop (otherwise the returned array might include branches).
По умолчанию: false

Список изменений

С версии 3.1.0 Введена.

Код wp_find_hierarchy_loop_tortoise_hare() WP 5.5.3

<?php
function wp_find_hierarchy_loop_tortoise_hare( $callback, $start, $override = array(), $callback_args = array(), $_return_loop = false ) {
	$tortoise        = $start;
	$hare            = $start;
	$evanescent_hare = $start;
	$return          = array();

	// Set evanescent_hare to one past hare.
	// Increment hare two steps.
	while (
		$tortoise
	&&
		( $evanescent_hare = isset( $override[ $hare ] ) ? $override[ $hare ] : call_user_func_array( $callback, array_merge( array( $hare ), $callback_args ) ) )
	&&
		( $hare = isset( $override[ $evanescent_hare ] ) ? $override[ $evanescent_hare ] : call_user_func_array( $callback, array_merge( array( $evanescent_hare ), $callback_args ) ) )
	) {
		if ( $_return_loop ) {
			$return[ $tortoise ]        = true;
			$return[ $evanescent_hare ] = true;
			$return[ $hare ]            = true;
		}

		// Tortoise got lapped - must be a loop.
		if ( $tortoise == $evanescent_hare || $tortoise == $hare ) {
			return $_return_loop ? $return : $tortoise;
		}

		// Increment tortoise by one step.
		$tortoise = isset( $override[ $tortoise ] ) ? $override[ $tortoise ] : call_user_func_array( $callback, array_merge( array( $tortoise ), $callback_args ) );
	}

	return false;
}