Reimplement e_tree_model sorting in pure PHP

Eliminated e107 dependency on the MySQL/MariaDB CREATE PROCEDURE permission

As a bonus, any attempt to use e107's native custom sorting (e.g.
`?field=cat_name&asc=desc`) will preserve the correct tree hierarchy.  The past
behavior was to sort as requested but keep showing depth, even though the
apparent tree hierarchy would be wrong.

Fixes: #3015
Supercedes: #2929

e107_handlers/admin_ui.php

@@ -4209,8 +4209,8 @@ class e_admin_controller_ui extends e_admin_controller
 			elseif($this->sortField && $this->sortParent && !deftrue('e_DEBUG_TREESORT')) // automated 'tree' sorting.
 			{
 			//	$qry = "SELECT SQL_CALC_FOUND_ROWS a. *, CASE WHEN a.".$this->sortParent." = 0 THEN a.".$this->sortField." ELSE b.".$this->sortField." + (( a.".$this->sortField.")/1000) END AS treesort FROM `#".$this->table."` AS a LEFT JOIN `#".$this->table."` AS b ON a.".$this->sortParent." = b.".$this->pid;
-				$qry                = $this->getParentChildQry();
+				$qry                = $this->getParentChildQry(true);
-				$this->listOrder	= '_treesort '; // .$this->sortField;
+				//$this->listOrder	= '_treesort '; // .$this->sortField;
 			//	$this->orderStep    = ($this->orderStep === 1) ? 100 : $this->orderStep;
 			}
 			else
@@ -4337,84 +4337,18 @@ class e_admin_controller_ui extends e_admin_controller
 
 	/**
 	 * Return a Parent/Child SQL Query based on sortParent and sortField variables
+	 *
+	 * Note: Since 2018-01-28, the queries were replaced with pure PHP sorting. See:
+	 *       https://github.com/e107inc/e107/issues/3015
+	 *
 	 * @param bool|false $orderby - include 'ORDER BY' in the qry.
 	 * @return string
 	 */
 	public function getParentChildQry($orderby=false)
 	{
-
+		return "SELECT SQL_CALC_FOUND_ROWS * FROM `#".$this->getTableName()."` ";
-		$parent= $this->getSortParent();
+		// Use the following return statement to break e107 native sorting but speed up tree creation by presorting for e_tree_model::arrayToTree()
-		$table = $this->getTableName();
+		#return "SELECT SQL_CALC_FOUND_ROWS * FROM `#".$this->getTableName()."` ORDER BY ".$this->getSortParent().", ".$this->getSortField();
-		$pid = $this->getPrimaryName();
-		$order = $this->getSortField();
-
-
-
-		$sql = "DROP FUNCTION IF EXISTS `getDepth` ;";
-
-		e107::getDb()->gen($sql);
-
-
-		$sql = "
-		CREATE FUNCTION `getDepth` (project_id INT) RETURNS int
-		BEGIN
-		    DECLARE depth INT;
-		    SET depth=1;
-
-		    WHILE project_id > 0 DO
-
-		        SELECT IFNULL(".$parent.",-1)
-		        INTO project_id
-		        FROM ( SELECT ".$parent." FROM `#".$table."` WHERE ".$pid." = project_id) AS t;
-
-		        IF project_id > 0 THEN
-		            SET depth = depth + 1;
-		        END IF;
-
-		    END WHILE;
-
-		    RETURN depth;
-
-		END
-		;
-		";
-
-
-		e107::getDb()->gen($sql);
-
-		$sql = "DROP FUNCTION IF EXISTS `getTreeSort`;";
-
-		e107::getDb()->gen($sql);
-        $sql = "
-        CREATE FUNCTION getTreeSort(incid INT)
-        RETURNS CHAR(255)
-        BEGIN
-                SET @parentstr = CONVERT(incid, CHAR);
-                SET @parent = -1;
-                label1: WHILE @parent != 0 DO
-                        SET @parent = (SELECT ".$parent." FROM `#".$table."` WHERE ".$pid." =incid);
-                        SET @order = (SELECT ".$order." FROM `#".$table."` WHERE ".$pid." =incid);
-                        SET @parentstr = CONCAT(if(@parent = 0,'',@parent), LPAD(@order,4,0), @parentstr);
-                        SET incid = @parent;
-                END WHILE label1;
-
-                RETURN @parentstr;
-        END
-   ;
-
-        ";
-
-
-        e107::getDb()->gen($sql);
-
-        $qry =  "SELECT SQL_CALC_FOUND_ROWS *, getTreeSort(".$pid.") as _treesort, getDepth(".$pid.") as _depth FROM `#".$table."` ";
-
-		if($orderby === true)
-		{
-			$qry .= " ORDER BY _treesort";
-		}
-
-		return $qry;
 	}
 
 
@@ -6256,7 +6190,14 @@ class e_admin_ui extends e_admin_controller_ui
 			->setFieldIdName($this->pid)
             ->setUrl($this->url)
 			->setMessageStackName('admin_ui_tree_'.$this->table)
-			->setParams(array('model_class' => 'e_admin_model', 'model_message_stack' => 'admin_ui_model_'.$this->table ,'db_query' => $this->listQry));
+			->setParams(array('model_class' => 'e_admin_model',
+			                  'model_message_stack' => 'admin_ui_model_'.$this->table ,
+			                  'db_query' => $this->listQry,
+			                  // Information necessary for PHP-based tree sort
+			                  'sort_parent' => $this->getSortParent(),
+			                  'sort_field' => $this->getSortField(),
+			                  'primary_field' => $this->getPrimaryName(),
+			                  ));
 
 		return $this;
 	}

e107_handlers/model_class.php

@@ -3331,7 +3331,12 @@ class e_tree_model extends e_front_model
 			if($sql->gen($this->getParam('db_query'), $this->getParam('db_debug') ? true : false))
 			{
 				$this->_total = is_integer($sql->total_results) ? $sql->total_results : false; //requires SQL_CALC_FOUND_ROWS in query - see db handler
-				while($tmp = $sql->db_Fetch())
+				$rows = self::flatTreeFromArray($sql->rows(),
+				                                $this->getParam('primary_field'),
+				                                $this->getParam('sort_parent'),
+				                                $this->getParam('sort_field')
+				                                );
+				foreach($rows as $tmp)
 				{
 					$tmp = new $class_name($tmp);
 					if($this->getParam('model_message_stack'))
@@ -3372,6 +3377,84 @@ class e_tree_model extends e_front_model
 		return $this;
 	}
 
+	/**
+	 * Depth-first sort a relational array with a parent field and a sort order field
+	 * @param array $rows Relational array with a parent field and a sort order field
+	 * @param string $primary_field The field name of the primary key (matches children to parents)
+	 * @param string $sort_parent The field name whose value is the parent ID
+	 * @param string $sort_field The field name whose value is the sort order in the current tree node
+	 * @return array Input array sorted depth-first as if it were a tree
+	 */
+	private static function flatTreeFromArray($rows, $primary_field, $sort_parent, $sort_field)
+	{
+		$rows_tree = self::arrayToTree($rows, $primary_field, $sort_parent);
+		return self::flattenTree($rows_tree, $sort_field);
+	}
+
+	/**
+	 * Converts a relational array with a parent field and a sort order field to a tree
+	 * @param array $rows Relational array with a parent field and a sort order field
+	 * @param string $primary_field The field name of the primary key (matches children to parents)
+	 * @param string $sort_parent The field name whose value is the parent ID
+	 * @return array Multidimensional array with child nodes under the "_children" key
+	 */
+	private static function arrayToTree($rows, $primary_field, $sort_parent)
+	{
+		$nodes = array();
+		$root = array($primary_field => 0);
+		$nodes[] = &$root;
+
+		while(!empty($nodes))
+		{
+			$node = &$nodes[0];
+			array_shift($nodes);
+			foreach($rows as $key => $row)
+			{
+				if(intval($row[$sort_parent]) === intval($node[$primary_field]))
+				{
+					$node['_children'][] = &$row;
+					unset($rows[$key]);
+					$nodes[] = &$row;
+					unset($row);
+				}
+			}
+		}
+
+		return array(0 => $root);
+	}
+
+	/**
+	 * Flattens a tree into a depth-first array, sorting each node by a field's values
+	 * @param array $tree Tree with child nodes under the "_children" key
+	 * @param string $sort_field The field name whose value is the sort order in the current tree node
+	 * @param int $depth The depth that this level of recursion is entering
+	 * @return array One-dimensional array in depth-first order with depth indicated by the "_depth" key
+	 */
+	private static function flattenTree($tree, $sort_field = null, $depth = 0)
+	{
+		$flat = array();
+
+		foreach($tree as $item)
+		{
+			$children = $item['_children'];
+			unset($item['_children']);
+			$item['_depth'] = $depth;
+			if($depth > 0)
+				$flat[] = $item;
+			if(is_array($children))
+			{
+				uasort($children, function($node1, $node2)
+				{
+					if(intval($node1[$sort_field]) === intval($node2[$sort_field])) return 0;
+					return intval($node1[$sort_field]) < intval($node2[$sort_field]) ? -1 : 1;
+				});
+				$flat = array_merge($flat, self::flattenTree($children, $sort_field, $depth+1));
+			}
+		}
+
+		return $flat;
+	}
+
 	/**
 	 * Get single model instance from the collection
 	 * @param integer $node_id