db_fields['id']; $id = $element->$id_field; //display this element $this->has_children = ! empty( $children_elements[ $id ] ); if ( isset( $args[0] ) && is_array( $args[0] ) ) { $args[0]['has_children'] = $this->has_children; // Backwards compatibility. } $cb_args = array_merge( array(&$output, $element, $depth), $args); call_user_func_array(array($this, 'start_el'), $cb_args); // descend only when the depth is right and there are childrens for this element if ( ($max_depth == 0 || $max_depth > $depth+1 ) && isset( $children_elements[$id]) ) { foreach( $children_elements[ $id ] as $child ){ if ( !isset($newlevel) ) { $newlevel = true; //start the child delimiter $cb_args = array_merge( array(&$output, $depth), $args); call_user_func_array(array($this, 'start_lvl'), $cb_args); } $this->display_element( $child, $children_elements, $max_depth, $depth + 1, $args, $output ); } unset( $children_elements[ $id ] ); } if ( isset($newlevel) && $newlevel ){ //end the child delimiter $cb_args = array_merge( array(&$output, $depth), $args); call_user_func_array(array($this, 'end_lvl'), $cb_args); } //end this element $cb_args = array_merge( array(&$output, $element, $depth), $args); call_user_func_array(array($this, 'end_el'), $cb_args); } /** * Display array of elements hierarchically. * * Does not assume any existing order of elements. * * $max_depth = -1 means flatly display every element. * $max_depth = 0 means display all levels. * $max_depth > 0 specifies the number of display levels. * * @since 2.1.0 * * @param array $elements An array of elements. * @param int $max_depth The maximum hierarchical depth. * @return string The hierarchical item output. */ public function walk( $elements, $max_depth ) { $args = array_slice(func_get_args(), 2); $output = ''; //invalid parameter or nothing to walk if ( $max_depth < -1 || empty( $elements ) ) { return $output; } $parent_field = $this->db_fields['parent']; // flat display if ( -1 == $max_depth ) { $empty_array = array(); foreach ( $elements as $e ) $this->display_element( $e, $empty_array, 1, 0, $args, $output ); return $output; } /* * Need to display in hierarchical order. * Separate elements into two buckets: top level and children elements. * Children_elements is two dimensional array, eg. * Children_elements[10][] contains all sub-elements whose parent is 10. */ $top_level_elements = array(); $children_elements = array(); foreach ( $elements as $e) { if ( 0 == $e->$parent_field ) $top_level_elements[] = $e; else $children_elements[ $e->$parent_field ][] = $e; } /* * When none of the elements is top level. * Assume the first one must be root of the sub elements. */ if ( empty($top_level_elements) ) { $first = array_slice( $elements, 0, 1 ); $root = $first[0]; $top_level_elements = array(); $children_elements = array(); foreach ( $elements as $e) { if ( $root->$parent_field == $e->$parent_field ) $top_level_elements[] = $e; else $children_elements[ $e->$parent_field ][] = $e; } } foreach ( $top_level_elements as $e ) $this->display_element( $e, $children_elements, $max_depth, 0, $args, $output ); /* * If we are displaying all levels, and remaining children_elements is not empty, * then we got orphans, which should be displayed regardless. */ if ( ( $max_depth == 0 ) && count( $children_elements ) > 0 ) { $empty_array = array(); foreach ( $children_elements as $orphans ) foreach( $orphans as $op ) $this->display_element( $op, $empty_array, 1, 0, $args, $output ); } return $output; } /** * paged_walk() - produce a page of nested elements * * Given an array of hierarchical elements, the maximum depth, a specific page number, * and number of elements per page, this function first determines all top level root elements * belonging to that page, then lists them and all of their children in hierarchical order. * * $max_depth = 0 means display all levels. * $max_depth > 0 specifies the number of display levels. * * @since 2.7.0 * * @param array $elements * @param int $max_depth The maximum hierarchical depth. * @param int $page_num The specific page number, beginning with 1. * @param int $per_page * @return string XHTML of the specified page of elements */ public function paged_walk( $elements, $max_depth, $page_num, $per_page ) { if ( empty( $elements ) || $max_depth < -1 ) { return ''; } $args = array_slice( func_get_args(), 4 ); $output = ''; $parent_field = $this->db_fields['parent']; $count = -1; if ( -1 == $max_depth ) $total_top = count( $elements ); if ( $page_num < 1 || $per_page < 0 ) { // No paging $paging = false; $start = 0; if ( -1 == $max_depth ) $end = $total_top; $this->max_pages = 1; } else { $paging = true; $start = ( (int)$page_num - 1 ) * (int)$per_page; $end = $start + $per_page; if ( -1 == $max_depth ) $this->max_pages = ceil($total_top / $per_page); } // flat display if ( -1 == $max_depth ) { if ( !empty($args[0]['reverse_top_level']) ) { $elements = array_reverse( $elements ); $oldstart = $start; $start = $total_top - $end; $end = $total_top - $oldstart; } $empty_array = array(); foreach ( $elements as $e ) { $count++; if ( $count < $start ) continue; if ( $count >= $end ) break; $this->display_element( $e, $empty_array, 1, 0, $args, $output ); } return $output; } /* * Separate elements into two buckets: top level and children elements. * Children_elements is two dimensional array, e.g. * $children_elements[10][] contains all sub-elements whose parent is 10. */ $top_level_elements = array(); $children_elements = array(); foreach ( $elements as $e) { if ( 0 == $e->$parent_field ) $top_level_elements[] = $e; else $children_elements[ $e->$parent_field ][] = $e; } $total_top = count( $top_level_elements ); if ( $paging ) $this->max_pages = ceil($total_top / $per_page); else $end = $total_top; if ( !empty($args[0]['reverse_top_level']) ) { $top_level_elements = array_reverse( $top_level_elements ); $oldstart = $start; $start = $total_top - $end; $end = $total_top - $oldstart; } if ( !empty($args[0]['reverse_children']) ) { foreach ( $children_elements as $parent => $children ) $children_elements[$parent] = array_reverse( $children ); } foreach ( $top_level_elements as $e ) { $count++; // For the last page, need to unset earlier children in order to keep track of orphans. if ( $end >= $total_top && $count < $start ) $this->unset_children( $e, $children_elements ); if ( $count < $start ) continue; if ( $count >= $end ) break; $this->display_element( $e, $children_elements, $max_depth, 0, $args, $output ); } if ( $end >= $total_top && count( $children_elements ) > 0 ) { $empty_array = array(); foreach ( $children_elements as $orphans ) foreach( $orphans as $op ) $this->display_element( $op, $empty_array, 1, 0, $args, $output ); } return $output; } /** * * @param array $elements * @return int */ public function get_number_of_root_elements( $elements ){ $num = 0; $parent_field = $this->db_fields['parent']; foreach ( $elements as $e) { if ( 0 == $e->$parent_field ) $num++; } return $num; } /** * Unset all the children for a given top level element. * * @param object $e * @param array $children_elements */ public function unset_children( $e, &$children_elements ){ if ( ! $e || ! $children_elements ) { return; } $id_field = $this->db_fields['id']; $id = $e->$id_field; if ( !empty($children_elements[$id]) && is_array($children_elements[$id]) ) foreach ( (array) $children_elements[$id] as $child ) $this->unset_children( $child, $children_elements ); unset( $children_elements[ $id ] ); } } // Walker