BUGFIX Re-enabled "Unused files" tab in AssetAdmin (fixed memory problems)

MINOR Moved getUsedFilesList() and getAssetList() from AssetAdmin to Folder (needed for Folder->getCMSFields()), changed their visibility from private to protected

git-svn-id: svn://svn.silverstripe.com/silverstripe/open/modules/sapphire/trunk@55081 467b73ca-7a2a-4603-9d3b-597d59a354a9

filesystem/Folder.php

@@ -391,8 +391,7 @@ class Folder extends File {
 					new LiteralField("UploadIframe",
 						$this->getUploadIframe()
 					)
-				)/* This has been disabled for now because of it's mass memory consumption
+				),
-				,
 				new Tab(_t('AssetAdmin.UNUSEDFILESTAB', "Unused files"),
 				    new LiteralField("UnusedAssets",
 	                    "<div id=\"UnusedAssets\"><h2>"._t('AssetAdmin.UNUSEDFILESTITLE', 'Unused files')."</h2>"
@@ -405,7 +404,7 @@ class Folder extends File {
 	                            <button class=\"action\">"._t('AssetAdmin.DELETEUNUSEDTHUMBNAILS', 'Delete unused thumbnails')."</button>
 	                        </div>"
 	                )     
-	            )*/
+	            )
 		    ),
 			new HiddenField("ID")
 		);
@@ -414,6 +413,69 @@ class Folder extends File {
 		
 		return $fields;
 	}
+	
+	/**
+     * Creates table for displaying unused files.
+     *
+     * @returns AssetTableField
+     */
+	protected function getAssetList() {
+		$where = $this->getUsedFilesList();
+        $assetList = new AssetTableField(
+            $this,
+            "AssetList",
+            "File", 
+			array("Title" => _t('AssetAdmin.TITLE', "Title"), "LinkedURL" => _t('AssetAdmin.FILENAME', "Filename")), 
+            "",
+            $where
+        );
+		$assetList->setPopupCaption(_t('AssetAdmin.VIEWASSET', "View Asset"));
+        $assetList->setPermissions(array("show","delete"));
+        $assetList->Markable = false;
+        return $assetList;
+        
+	}
+	
+	/**
+     * Looks for files used in system and create where clause which contains all ID's of files.
+     * 
+     * @returns String where clause which will work as filter.
+     */
+	protected function getUsedFilesList() {
+	    $result = DB::query("SELECT DISTINCT FileID FROM SiteTree_ImageTracking");
+        $usedFiles = array();
+	    $where = "";
+        if($result->numRecords() > 0) {
+            while($nextResult = $result->next()){
+                $where .= $nextResult['FileID'] . ','; 
+            }        
+        }
+        $classes = ClassInfo::subclassesFor('SiteTree');
+        foreach($classes as $className) {
+            $query = singleton($className)->extendedSQL();
+            $ids = $query->execute()->column();
+            if(!count($ids)) continue;
+            
+            foreach(singleton($className)->has_one() as $fieldName => $joinClass) {
+                if($joinClass == 'Image' || $joinClass == 'File')  {
+                	foreach($ids as $id) {
+                		$object = DataObject::get_by_id($className, $id);
+                		if($object->$fieldName != NULL) $usedFiles[] = $object->$fieldName;
+		                unset($object);
+                    }
+                } elseif($joinClass == 'Folder') {
+                    // @todo 
+                }
+            }
+        }
+        foreach($usedFiles as $file) {
+            $where .= $file->ID . ',';     
+        }
+        if($where == "") return "(ClassName = 'File' OR ClassName =  'Image')";
+        $where = substr($where,0,strlen($where)-1);
+        $where = "`File`.ID NOT IN (" . $where . ") AND (ClassName = 'File' OR ClassName =  'Image')";
+        return $where;
+	}
 
 	/**
 	 * Display the upload form.  Returns an iframe tag that will show admin/assets/uploadiframe.