From 66b6717e6b3ec2cd9ced7040cd330d7add19dcb6 Mon Sep 17 00:00:00 2001
From: Andrey Andreev <narf@devilix.net>
Date: Tue, 29 Aug 2017 16:01:18 +0300
Subject: Polish changes from & add changelog entry for PR #5242

Also, further simplified the join() logic
---
 system/database/DB_query_builder.php | 37 ++++++++----------------------------
 1 file changed, 8 insertions(+), 29 deletions(-)

(limited to 'system')

diff --git a/system/database/DB_query_builder.php b/system/database/DB_query_builder.php
index 9564e8870..d35d84d6d 100644
--- a/system/database/DB_query_builder.php
+++ b/system/database/DB_query_builder.php
@@ -525,26 +525,8 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 	 */
 	public function join($table, $cond, $type = '', $escape = NULL)
 	{
-		$natural_join = FALSE;
-
-		if ($type !== '')
-		{
-			$type = strtoupper(trim($type));
-
-			if (in_array($type, array('LEFT', 'RIGHT', 'OUTER', 'INNER', 'LEFT OUTER', 'RIGHT OUTER'), TRUE))
-			{
-				$type .= ' ';
-			}
-			elseif (in_array($type, array('NATURAL', 'NATURAL LEFT', 'NATURAL RIGHT', 'NATURAL LEFT OUTER', 'NATURAL RIGHT OUTER'), TRUE))
-			{
-				$type .= ' ';
-				$natural_join = TRUE;
-			}
-			else
-			{
-				$type = '';
-			}
-		}
+		$type = strtoupper(trim($type));
+		preg_match('#^(NATURAL(?=\s|$)\s*)?((LEFT|RIGHT)(?=\s|$))?\s*(INNER|OUTER)?$#', $type) OR $type = '';
 
 		// Extract any aliases that might exist. We use this information
 		// in the protect_identifiers to know whether to add a table prefix
@@ -552,7 +534,11 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 
 		is_bool($escape) OR $escape = $this->_protect_identifiers;
 
-		if ( ! $this->_has_operator($cond))
+		if (strpos($type, 'NATURAL') === 0)
+		{
+			$cond = '';
+		}
+		elseif ( ! $this->_has_operator($cond))
 		{
 			$cond = ' USING ('.($escape ? $this->escape_identifiers($cond) : $cond).')';
 		}
@@ -601,14 +587,7 @@ abstract class CI_DB_query_builder extends CI_DB_driver {
 		}
 
 		// Assemble the JOIN statement
-		if ($natural_join === FALSE)
-		{
-			$this->qb_join[] = $join = $type.'JOIN '.$table.$cond;
-		}
-		else
-		{
-			$this->qb_join[] = $join = $type.'JOIN '.$table;
-		}
+		$this->qb_join[] = $join = $type.' JOIN '.$table.$cond;
 
 		if ($this->qb_caching === TRUE)
 		{
-- 
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