From a415c29efee45520ae252d2aa28f1083a521cd7b Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Wed, 17 Apr 2024 09:56:49 +0200
Subject: Adding upstream version 6.4.3+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 wp-includes/class-wp-walker.php | 449 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 449 insertions(+)
 create mode 100644 wp-includes/class-wp-walker.php

(limited to 'wp-includes/class-wp-walker.php')

diff --git a/wp-includes/class-wp-walker.php b/wp-includes/class-wp-walker.php
new file mode 100644
index 0000000..d8c00a3
--- /dev/null
+++ b/wp-includes/class-wp-walker.php
@@ -0,0 +1,449 @@
+<?php
+/**
+ * A class for displaying various tree-like structures.
+ *
+ * Extend the Walker class to use it, see examples below. Child classes
+ * do not need to implement all of the abstract methods in the class. The child
+ * only needs to implement the methods that are needed.
+ *
+ * @since 2.1.0
+ *
+ * @package WordPress
+ * @abstract
+ */
+#[AllowDynamicProperties]
+class Walker {
+	/**
+	 * What the class handles.
+	 *
+	 * @since 2.1.0
+	 * @var string
+	 */
+	public $tree_type;
+
+	/**
+	 * DB fields to use.
+	 *
+	 * @since 2.1.0
+	 * @var string[]
+	 */
+	public $db_fields;
+
+	/**
+	 * Max number of pages walked by the paged walker.
+	 *
+	 * @since 2.7.0
+	 * @var int
+	 */
+	public $max_pages = 1;
+
+	/**
+	 * Whether the current element has children or not.
+	 *
+	 * To be used in start_el().
+	 *
+	 * @since 4.0.0
+	 * @var bool
+	 */
+	public $has_children;
+
+	/**
+	 * Starts the list before the elements are added.
+	 *
+	 * The $args parameter holds additional values that may be used with the child
+	 * class methods. This method is called at the start of the output list.
+	 *
+	 * @since 2.1.0
+	 * @abstract
+	 *
+	 * @param string $output Used to append additional content (passed by reference).
+	 * @param int    $depth  Depth of the item.
+	 * @param array  $args   An array of additional arguments.
+	 */
+	public function start_lvl( &$output, $depth = 0, $args = array() ) {}
+
+	/**
+	 * Ends the list of after the elements are added.
+	 *
+	 * The $args parameter holds additional values that may be used with the child
+	 * class methods. This method finishes the list at the end of output of the elements.
+	 *
+	 * @since 2.1.0
+	 * @abstract
+	 *
+	 * @param string $output Used to append additional content (passed by reference).
+	 * @param int    $depth  Depth of the item.
+	 * @param array  $args   An array of additional arguments.
+	 */
+	public function end_lvl( &$output, $depth = 0, $args = array() ) {}
+
+	/**
+	 * Starts the element output.
+	 *
+	 * The $args parameter holds additional values that may be used with the child
+	 * class methods. Also includes the element output.
+	 *
+	 * @since 2.1.0
+	 * @since 5.9.0 Renamed `$object` (a PHP reserved keyword) to `$data_object` for PHP 8 named parameter support.
+	 * @abstract
+	 *
+	 * @param string $output            Used to append additional content (passed by reference).
+	 * @param object $data_object       The data object.
+	 * @param int    $depth             Depth of the item.
+	 * @param array  $args              An array of additional arguments.
+	 * @param int    $current_object_id Optional. ID of the current item. Default 0.
+	 */
+	public function start_el( &$output, $data_object, $depth = 0, $args = array(), $current_object_id = 0 ) {}
+
+	/**
+	 * Ends the element output, if needed.
+	 *
+	 * The $args parameter holds additional values that may be used with the child class methods.
+	 *
+	 * @since 2.1.0
+	 * @since 5.9.0 Renamed `$object` (a PHP reserved keyword) to `$data_object` for PHP 8 named parameter support.
+	 * @abstract
+	 *
+	 * @param string $output      Used to append additional content (passed by reference).
+	 * @param object $data_object The data object.
+	 * @param int    $depth       Depth of the item.
+	 * @param array  $args        An array of additional arguments.
+	 */
+	public function end_el( &$output, $data_object, $depth = 0, $args = array() ) {}
+
+	/**
+	 * Traverses elements to create list from elements.
+	 *
+	 * Display one element if the element doesn't have any children otherwise,
+	 * display the element and its children. Will only traverse up to the max
+	 * depth and no ignore elements under that depth. It is possible to set the
+	 * max depth to include all depths, see walk() method.
+	 *
+	 * This method should not be called directly, use the walk() method instead.
+	 *
+	 * @since 2.5.0
+	 *
+	 * @param object $element           Data object.
+	 * @param array  $children_elements List of elements to continue traversing (passed by reference).
+	 * @param int    $max_depth         Max depth to traverse.
+	 * @param int    $depth             Depth of current element.
+	 * @param array  $args              An array of arguments.
+	 * @param string $output            Used to append additional content (passed by reference).
+	 */
+	public function display_element( $element, &$children_elements, $max_depth, $depth, $args, &$output ) {
+		if ( ! $element ) {
+			return;
+		}
+
+		$id_field = $this->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; // Back-compat.
+		}
+
+		$this->start_el( $output, $element, $depth, ...array_values( $args ) );
+
+		// Descend only when the depth is right and there are children for this element.
+		if ( ( 0 == $max_depth || $max_depth > $depth + 1 ) && isset( $children_elements[ $id ] ) ) {
+
+			foreach ( $children_elements[ $id ] as $child ) {
+
+				if ( ! isset( $newlevel ) ) {
+					$newlevel = true;
+					// Start the child delimiter.
+					$this->start_lvl( $output, $depth, ...array_values( $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.
+			$this->end_lvl( $output, $depth, ...array_values( $args ) );
+		}
+
+		// End this element.
+		$this->end_el( $output, $element, $depth, ...array_values( $args ) );
+	}
+
+	/**
+	 * Displays 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.
+	 * $max_depth > 0 specifies the number of display levels.
+	 *
+	 * @since 2.1.0
+	 * @since 5.3.0 Formalized the existing `...$args` parameter by adding it
+	 *              to the function signature.
+	 *
+	 * @param array $elements  An array of elements.
+	 * @param int   $max_depth The maximum hierarchical depth.
+	 * @param mixed ...$args   Optional additional arguments.
+	 * @return string The hierarchical item output.
+	 */
+	public function walk( $elements, $max_depth, ...$args ) {
+		$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. Example:
+		 * Children_elements[10][] contains all sub-elements whose parent is 10.
+		 */
+		$top_level_elements = array();
+		$children_elements  = array();
+		foreach ( $elements as $e ) {
+			if ( empty( $e->$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 ( ( 0 == $max_depth ) && 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;
+	}
+
+	/**
+	 * Produces 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.
+	 * $max_depth > 0 specifies the number of display levels.
+	 *
+	 * @since 2.7.0
+	 * @since 5.3.0 Formalized the existing `...$args` parameter by adding it
+	 *              to the function signature.
+	 *
+	 * @param array $elements  An array of elements.
+	 * @param int   $max_depth The maximum hierarchical depth.
+	 * @param int   $page_num  The specific page number, beginning with 1.
+	 * @param int   $per_page  Number of elements per page.
+	 * @param mixed ...$args   Optional additional arguments.
+	 * @return string XHTML of the specified page of elements.
+	 */
+	public function paged_walk( $elements, $max_depth, $page_num, $per_page, ...$args ) {
+		if ( empty( $elements ) || $max_depth < -1 ) {
+			return '';
+		}
+
+		$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 ( empty( $e->$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;
+	}
+
+	/**
+	 * Calculates the total number of root elements.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @param array $elements Elements to list.
+	 * @return int Number of root elements.
+	 */
+	public function get_number_of_root_elements( $elements ) {
+		$num          = 0;
+		$parent_field = $this->db_fields['parent'];
+
+		foreach ( $elements as $e ) {
+			if ( empty( $e->$parent_field ) ) {
+				++$num;
+			}
+		}
+		return $num;
+	}
+
+	/**
+	 * Unsets all the children for a given top level element.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @param object $element           The top level element.
+	 * @param array  $children_elements The children elements.
+	 */
+	public function unset_children( $element, &$children_elements ) {
+		if ( ! $element || ! $children_elements ) {
+			return;
+		}
+
+		$id_field = $this->db_fields['id'];
+		$id       = $element->$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 ] );
+	}
+}
-- 
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