関数 wp_find_hierarchy_loop_tortoise_hare()
定義ファイル :/blog/wp-includes/functions.php 21
wp_find_hierarchy_loop_tortoise_hare()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 | /** * 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. * * @since 3.1.0 * @access private * * @param callback $callback Function that accepts ( ID, callback_arg, ... ) and outputs parent_ID. * @param int $start The ID to start the loop check at. * @param array $override Optional. An array of ( ID => parent_ID, ... ) to use instead of $callback. * Default empty array. * @param array $callback_args Optional. Additional arguments to send to $callback. Default empty array. * @param bool $_return_loop Optional. 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). Default false. * @return mixed Scalar ID of some arbitrary member of the loop, or array of IDs of all members of loop if * $_return_loop */ function wp_find_hierarchy_loop_tortoise_hare( $callback, $start, $override = array(), $callback_args = array(), $_return_loop = false ) { $tortoise = $hare = $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] = $return[$evanescent_hare] = $return[$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; } |