5 files changed, 15 insertions, 10 deletions
diff --git a/phpBB/phpbb/cache/driver/apcu.php b/phpBB/phpbb/cache/driver/apcu.php
index 40192e4026..c96cf0de57 100644
--- a/phpBB/phpbb/cache/driver/apcu.php
+++ b/phpBB/phpbb/cache/driver/apcu.php
@@ -25,7 +25,11 @@ class apcu extends \phpbb\cache\driver\memory
 	*/
 	function purge()
 	{
-		apcu_clear_cache();
+		/*
+		* Use an iterator to selectively delete our cache entries without disturbing
+		* any other cache users (e.g. other phpBB boards hosted on this server)
+		*/
+		apcu_delete(new \APCUIterator('#^' . $this->key_prefix . '#'));
 
 		parent::purge();
 	}
diff --git a/phpBB/phpbb/cache/driver/base.php b/phpBB/phpbb/cache/driver/base.php
index f4b3dc278d..3eca521148 100644
--- a/phpBB/phpbb/cache/driver/base.php
+++ b/phpBB/phpbb/cache/driver/base.php
@@ -123,7 +123,7 @@ abstract class base implements \phpbb\cache\driver\driver_interface
 	*/
 	function sql_fetchrow($query_id)
 	{
-		if ($this->sql_row_pointer[$query_id] < sizeof($this->sql_rowset[$query_id]))
+		if ($this->sql_row_pointer[$query_id] < count($this->sql_rowset[$query_id]))
 		{
 			return $this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]++];
 		}
@@ -136,7 +136,7 @@ abstract class base implements \phpbb\cache\driver\driver_interface
 	*/
 	function sql_fetchfield($query_id, $field)
 	{
-		if ($this->sql_row_pointer[$query_id] < sizeof($this->sql_rowset[$query_id]))
+		if ($this->sql_row_pointer[$query_id] < count($this->sql_rowset[$query_id]))
 		{
 			return (isset($this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]][$field])) ? $this->sql_rowset[$query_id][$this->sql_row_pointer[$query_id]++][$field] : false;
 		}
@@ -149,7 +149,7 @@ abstract class base implements \phpbb\cache\driver\driver_interface
 	*/
 	function sql_rowseek($rownum, $query_id)
 	{
-		if ($rownum >= sizeof($this->sql_rowset[$query_id]))
+		if ($rownum >= count($this->sql_rowset[$query_id]))
 		{
 			return false;
 		}
diff --git a/phpBB/phpbb/cache/driver/file.php b/phpBB/phpbb/cache/driver/file.php
index e9d2ba8e04..de6f444251 100644
--- a/phpBB/phpbb/cache/driver/file.php
+++ b/phpBB/phpbb/cache/driver/file.php
@@ -135,7 +135,7 @@ class file extends \phpbb\cache\driver\base
 
 		if (file_exists($this->cache_dir . 'data_global.' . $phpEx))
 		{
-			if (!sizeof($this->vars))
+			if (!count($this->vars))
 			{
 				$this->load();
 			}
@@ -290,7 +290,7 @@ class file extends \phpbb\cache\driver\base
 		}
 		else
 		{
-			if (!sizeof($this->vars))
+			if (!count($this->vars))
 			{
 				$this->load();
 			}
diff --git a/phpBB/phpbb/cache/driver/memory.php b/phpBB/phpbb/cache/driver/memory.php
index cc03804705..eba9549877 100644
--- a/phpBB/phpbb/cache/driver/memory.php
+++ b/phpBB/phpbb/cache/driver/memory.php
@@ -51,10 +51,11 @@ abstract class memory extends \phpbb\cache\driver\base
 	function load()
 	{
 		// grab the global cache
-		$this->vars = $this->_read('global');
+		$data = $this->_read('global');
 
-		if ($this->vars !== false)
+		if ($data !== false)
 		{
+			$this->vars = $data;
 			return true;
 		}
 
@@ -188,7 +189,7 @@ abstract class memory extends \phpbb\cache\driver\base
 		}
 		else
 		{
-			if (!sizeof($this->vars))
+			if (!count($this->vars))
 			{
 				$this->load();
 			}
diff --git a/phpBB/phpbb/cache/service.php b/phpBB/phpbb/cache/service.php
index 8a4366fed1..502ae27625 100644
--- a/phpBB/phpbb/cache/service.php
+++ b/phpBB/phpbb/cache/service.php
@@ -227,7 +227,7 @@ class service
 				// Store allowed extensions forum wise
 				if ($row['allow_group'])
 				{
-					$extensions['_allowed_post'][$extension] = (!sizeof($allowed_forums)) ? 0 : $allowed_forums;
+					$extensions['_allowed_post'][$extension] = (!count($allowed_forums)) ? 0 : $allowed_forums;
 				}
 
 				if ($row['allow_in_pm'])