General: Reduce cell caching overhead using dirty flag to ensure that cells are only rewritten to the cache if they have actually been changed

git-svn-id: https://phpexcel.svn.codeplex.com/svn/trunk@72227 2327b42d-5241-43d6-9e2a-de5ac946f064

Classes/PHPExcel/CachedObjectStorage/APC.php

@@ -41,12 +41,15 @@ class PHPExcel_CachedObjectStorage_APC extends PHPExcel_CachedObjectStorage_Cach
 
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			if (!apc_store($this->_cachePrefix.$this->_currentObjectID.'.cache',serialize($this->_currentObject),$this->_cacheTime)) {
 				$this->__destruct();
 				throw new Exception('Failed to store cell '.$cellID.' in APC');
 			}
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -67,6 +70,7 @@ class PHPExcel_CachedObjectStorage_APC extends PHPExcel_CachedObjectStorage_Cach
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/CacheBase.php

@@ -57,6 +57,13 @@ class PHPExcel_CachedObjectStorage_CacheBase {
 	protected $_currentObjectID = null;
 
 
+	/**
+	 *	Flag indicating whether the currently active Cell requires saving
+	 *
+	 *	@var boolean
+	 */
+	protected $_currentCellIsDirty = true;
+
 	/**
 	 *	An array of cells or cell pointers for the worksheet cells held in this cache,
 	 *		and indexed by their coordinate address within the worksheet
@@ -118,6 +125,7 @@ class PHPExcel_CachedObjectStorage_CacheBase {
 			$this->_cellCache[$pCoord]->detach();
 			unset($this->_cellCache[$pCoord]);
 		}
+		$this->_currentCellIsDirty = false;
 	}	//	function deleteCacheData()
 
 

Classes/PHPExcel/CachedObjectStorage/DiscISAM.php

@@ -40,6 +40,7 @@ class PHPExcel_CachedObjectStorage_DiscISAM extends PHPExcel_CachedObjectStorage
 
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			fseek($this->_fileHandle,0,SEEK_END);
@@ -48,6 +49,8 @@ class PHPExcel_CachedObjectStorage_DiscISAM extends PHPExcel_CachedObjectStorage
 			$this->_cellCache[$this->_currentObjectID]	= array('ptr' => $offset,
 																'sz'  => ftell($this->_fileHandle) - $offset
 															   );
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -67,6 +70,7 @@ class PHPExcel_CachedObjectStorage_DiscISAM extends PHPExcel_CachedObjectStorage
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/Memcache.php

@@ -43,6 +43,7 @@ class PHPExcel_CachedObjectStorage_Memcache extends PHPExcel_CachedObjectStorage
 
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			$obj = serialize($this->_currentObject);
@@ -52,6 +53,8 @@ class PHPExcel_CachedObjectStorage_Memcache extends PHPExcel_CachedObjectStorage
 					throw new Exception('Failed to store cell '.$cellID.' in MemCache');
 				}
 			}
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -72,6 +75,7 @@ class PHPExcel_CachedObjectStorage_Memcache extends PHPExcel_CachedObjectStorage
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/MemoryGZip.php

@@ -36,9 +36,12 @@
 class PHPExcel_CachedObjectStorage_MemoryGZip extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache {
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			$this->_cellCache[$this->_currentObjectID] = gzdeflate(serialize($this->_currentObject));
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -58,6 +61,7 @@ class PHPExcel_CachedObjectStorage_MemoryGZip extends PHPExcel_CachedObjectStora
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/MemorySerialized.php

@@ -36,9 +36,12 @@
 class PHPExcel_CachedObjectStorage_MemorySerialized extends PHPExcel_CachedObjectStorage_CacheBase implements PHPExcel_CachedObjectStorage_ICache {
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			$this->_cellCache[$this->_currentObjectID] = serialize($this->_currentObject);
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -58,6 +61,7 @@ class PHPExcel_CachedObjectStorage_MemorySerialized extends PHPExcel_CachedObjec
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/PHPTemp.php

@@ -41,6 +41,7 @@ class PHPExcel_CachedObjectStorage_PHPTemp extends PHPExcel_CachedObjectStorage_
 	private $_memoryCacheSize = null;
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			fseek($this->_fileHandle,0,SEEK_END);
@@ -49,6 +50,8 @@ class PHPExcel_CachedObjectStorage_PHPTemp extends PHPExcel_CachedObjectStorage_
 			$this->_cellCache[$this->_currentObjectID]	= array('ptr' => $offset,
 																'sz'  => ftell($this->_fileHandle) - $offset
 															   );
+			$this->_currentCellIsDirty = false;
+		}
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
 
@@ -68,6 +71,7 @@ class PHPExcel_CachedObjectStorage_PHPTemp extends PHPExcel_CachedObjectStorage_
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

Classes/PHPExcel/CachedObjectStorage/Wincache.php

@@ -41,6 +41,7 @@ class PHPExcel_CachedObjectStorage_Wincache extends PHPExcel_CachedObjectStorage
 
 
 	private function _storeData() {
+		if ($this->_currentCellIsDirty) {
 			$this->_currentObject->detach();
 
 			$obj = serialize($this->_currentObject);
@@ -55,6 +56,8 @@ class PHPExcel_CachedObjectStorage_Wincache extends PHPExcel_CachedObjectStorage
 					throw new Exception('Failed to store cell '.$cellID.' in WinCache');
 				}
 			}
+			$this->_currentCellIsDirty = false;
+		}
 
 		$this->_currentObjectID = $this->_currentObject = null;
 	}	//	function _storeData()
@@ -76,6 +79,7 @@ class PHPExcel_CachedObjectStorage_Wincache extends PHPExcel_CachedObjectStorage
 
 		$this->_currentObjectID = $pCoord;
 		$this->_currentObject = $cell;
+		$this->_currentCellIsDirty = true;
 
 		return $cell;
 	}	//	function addCacheData()

changelog.txt

@@ -25,6 +25,7 @@
 
 Fixed in SVN:
 - General:  (MBaker) Fix to build to ensure that Examples are included with the documentation
+- General:  (MBaker) Reduce cell caching overhead using dirty flag to ensure that cells are only rewritten to the cache if they have actually been changed
 - Bugfix:   (MBaker) Work item 15459 - Invalid cell coordinate in Autofilter for Excel2007 Writer
 - Bugfix:   (MBaker) Work item 15518 - PCLZip library issue
 - Bugfix:   (MBaker) Work item 15537 - Excel2007 Reader canRead function bug