From f9046105b8f19b6defc669c1bc28b0b3bad7642b Mon Sep 17 00:00:00 2001
From: Tomasz Narloch <csthomas@users.noreply.github.com>
Date: Fri, 28 Apr 2017 22:05:10 +0200
Subject: [PATCH] Remove empty locked cache file if callback function terminate
 process (#15592)

* Remove empty locked cache file if callback function terminate process

* Add comments and @
---
 libraries/joomla/cache/storage/file.php | 32 +++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/libraries/joomla/cache/storage/file.php b/libraries/joomla/cache/storage/file.php
index f2dba86e5f9ab..0c849755f868f 100644
--- a/libraries/joomla/cache/storage/file.php
+++ b/libraries/joomla/cache/storage/file.php
@@ -45,6 +45,32 @@ public function __construct($options = array())
 	{
 		parent::__construct($options);
 		$this->_root = $options['cachebase'];
+
+		// Workaround for php 5.3
+		$locked_files = &$this->_locked_files;
+
+		// Remove empty locked files at script shutdown.
+		$clearAtShutdown = function () use (&$locked_files)
+		{
+			foreach ($locked_files as $path => $handle)
+			{
+				if (is_resource($handle))
+				{
+					@flock($handle, LOCK_UN);
+					@fclose($handle);
+				}
+
+				// Delete only the existing file if it is empty.
+				if (@filesize($path) === 0)
+				{
+					@unlink($path);
+				}
+
+				unset($locked_files[$path]);
+			}
+		};
+
+		register_shutdown_function($clearAtShutdown);
 	}
 
 	/**
@@ -420,6 +446,12 @@ protected function _checkExpire($id, $group)
 				return false;
 			}
 
+			// If now the file does not exist then return false too.
+			if (@filesize($path) == 0)
+			{
+				return false;
+			}
+
 			return true;
 		}