Changeset 8939

Timestamp:

09/19/2008 06:59:47 AM (17 years ago)

Author:

ryan

Message:

Add paging to Walker class. Props hailin. fixes #7743

File:

• trunk/wp-includes/classes.php (modified) (4 diffs)

trunk/wp-includes/classes.php

@@ -486 +486 @@
      * PHP4 Constructor - Does nothing.
      *
-     * Call main() method when ready to run setup. 
+     * Call main() method when ready to run setup.
      *
      * @since 2.0.0
@@ -819 +819 @@
         $id = $element->$id_field;
 
-        // descend only the depth is right and there are chilrens for this element
+        // 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]) ) {
 
@@ -918 +918 @@
             $this->display_element( $e, $children_elements, $max_depth, 0, $args, $output );
 
-        /* 
-         * if we are displaying all levels, and remaining children_elements is not empty, 
+        /*
+         * if we are displaying all levels, and remaining children_elements is not empty,
          * then we got orphans, which should be displayed regardless
          */
@@ -930 +930 @@
 
          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.
+     *
+     * @package WordPress
+     * @since 2.7
+     * @param $max_depth = 0  means display all levels; $max_depth > 0  specifies the number of display levels.
+     * @param $page_num the specific page number, beginning with 1.
+     * @return XHTML of the specified page of elements
+     */
+    function paged_walk( $elements, $max_depth, $page_num, $per_page ) {
+
+        /* sanity check */
+        if ( empty($elements) || $max_depth < 0 )
+            return '';
+
+        $args = array_slice( func_get_args(), 4 );
+        $output = '';
+
+        $id_field = $this->db_fields['id'];
+        $parent_field = $this->db_fields['parent'];
+
+        /*
+         * seperate 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;
+        }
+
+        $count = -1;
+        $total_top = count( $top_level_elements );
+        if ( $page_num < 1 || $per_page < 0  ) {
+            $start = 0;
+            $end = $total_top;
+        } else {
+            $start = ( (int)$page_num - 1 ) * (int)$per_page;
+            $end   = $start + $per_page;
+        }
+
+        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;
+    }
+
+    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
+    function unset_children( $e, &$children_elements ){
+
+        if ( !$e || !$children_elements )
+            return;
+
+        $id_field = $this->db_fields['id'];
+        $id = $e->$id_field;
+
+        foreach ( (array)$children_elements[$id] as $child )
+            $this->unset_children( $child, $children_elements );
+
+        unset( $children_elements[$id] );
+
     }
 }