From f6aa1ca1aa6737924a86fa74f6b332375fa0f048 Mon Sep 17 00:00:00 2001
From: Ralf Becker <ralfbecker@outdoor-training.de>
Date: Tue, 23 Oct 2012 07:49:42 +0000
Subject: [PATCH] * API: only cache in APC by default, if it has at least 64M
 of shared memory, otherwise use filesystem

---
 phpgwapi/inc/class.egw_cache.inc.php     | 13 +++++-----
 phpgwapi/inc/class.egw_cache_apc.inc.php | 33 ++++++++++++++++++++++++
 2 files changed, 39 insertions(+), 7 deletions(-)

diff --git a/phpgwapi/inc/class.egw_cache.inc.php b/phpgwapi/inc/class.egw_cache.inc.php
index a938d0fab8..271b7942f4 100644
--- a/phpgwapi/inc/class.egw_cache.inc.php
+++ b/phpgwapi/inc/class.egw_cache.inc.php
@@ -518,13 +518,6 @@ class egw_cache
 	}
 }
 
-// setting apc as default provide, if apc_fetch function exists AND not cli or apc enabled for cli
-if (is_null(egw_cache::$default_provider))
-{
-	egw_cache::$default_provider = function_exists('apc_fetch') && (PHP_SAPI != 'cli' || ini_get('apc.enable_cli')) ?
-		'egw_cache_apc' : 'egw_cache_files';
-}
-
 /**
  * Interface for a caching provider for tree and instance level
  *
@@ -623,6 +616,12 @@ abstract class egw_cache_provider_check implements egw_cache_provider
 	}
 }
 
+// setting apc as default provider, if apc_fetch function exists AND further checks in egw_cache_apc recommed it
+if (is_null(egw_cache::$default_provider))
+{
+	egw_cache::$default_provider = function_exists('apc_fetch') && egw_cache_apc::available() ? 'egw_cache_apc' : 'egw_cache_files';
+}
+
 // some testcode, if this file is called via it's URL
 // can be run on command-line: sudo php -d apc.enable_cli=1 -f phpgwapi/inc/class.egw_cache.inc.php
 /*if (isset($_SERVER['SCRIPT_FILENAME']) && realpath($_SERVER['SCRIPT_FILENAME']) == __FILE__)
diff --git a/phpgwapi/inc/class.egw_cache_apc.inc.php b/phpgwapi/inc/class.egw_cache_apc.inc.php
index 649735a623..6cc83c0645 100644
--- a/phpgwapi/inc/class.egw_cache_apc.inc.php
+++ b/phpgwapi/inc/class.egw_cache_apc.inc.php
@@ -40,6 +40,39 @@ class egw_cache_apc extends egw_cache_provider_check implements egw_cache_provid
 		}
 	}
 
+	/**
+	 * Check if APC is available for caching user data
+	 *
+	 * Default shared memory size of 32M is just enough for the byte code cache,
+	 * but not for caching user data, we only use APC by default if we have at least 64M.
+	 *
+	 * @return boolean true: apc available, false: not
+	 */
+	public static function available()
+	{
+		$available = false;
+		if (function_exists('apc_fetch') && (PHP_SAPI != 'cli' || ini_get('apc.enable_cli')))
+		{
+			$size = ini_get('apc.shm_size');
+
+			switch(strtoupper(substr($size, -1)))
+			{
+				case 'G':
+					$size *= 1024;
+				case 'M':
+					$size *= 1024;
+				case 'K':
+					$size *= 1024;
+			}
+			$size *= ini_get('apc.shm_segments');
+
+			// only cache in APC, if we have at least 64M available (default is 32M)
+			$available = $size >= 64*1024*1024;
+		}
+		//error_log(__METHOD__."() size=$size returning ".array2string($available));
+		return $available;
+	}
+
 	/**
 	 * Stores some data in the cache
 	 *