--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/photosgallery/collectionframework/thumbnailcreator/inc/glxtntaskmanager.h	Thu Dec 17 08:45:44 2009 +0200
@@ -0,0 +1,151 @@
+/*
+* Copyright (c) 2008-2009 Nokia Corporation and/or its subsidiary(-ies). 
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:    Task manager for multiple tasks. Allows asynchronosity and 
+*                tracking/callback for long running tasks.
+*
+*/
+
+
+
+
+/**
+ * @internal reviewed 30/07/2007 by Simon Brooks
+ */
+
+#ifndef C_GLXTNTASKMANAGER_H
+#define C_GLXTNTASKMANAGER_H
+
+#include "glxtnstd.h"
+#include <glxmediaid.h>
+#include <e32base.h>
+
+// Forward declarations
+class CGlxtnTask;
+class MGlxtnThumbnailStorage;
+
+/**
+ * Active object which maintains a priority queue of long running tasks, and
+ * provides callback upon task completion or error.
+ *
+ * The highest priority task in the queue which has @ref CGlxtnTask::TState "state"
+ * EStarting is started and the task manager's RunL then delegates to the task's
+ * RunL until the task is complete, or is cancelled.  The task is then deleted
+ * and another task is started, if any are ready to start.
+ *
+ * The task manager's DoCancel and RunError methods also delegate to the current
+ * task, if any.
+ *
+ * @ingroup glx_thumbnail_creator
+ */
+NONSHARABLE_CLASS(CGlxtnTaskManager) : public CActive
+    {
+public:
+	enum TExecutionOrder
+		{
+		ELastOut,	// Old tasks with the same priority get executed before the new task
+		EFirstOut	// New task gets executed before other tasks with the same priority
+		};
+public:
+    /**
+     * Static constructor.
+     */
+    static CGlxtnTaskManager* NewL();
+    
+    /**
+     * Destructor.
+     */
+    ~CGlxtnTaskManager();
+    
+public:
+    /**
+     * @returns CVieTask task at an index
+     */
+
+    inline CGlxtnTask* Task(TInt aIndex) const { return iTasks[aIndex]; };
+
+     /**
+      * Returns the highest priority task with the id.
+      * If there are multiple tasks with same id and priority, 
+      * returns the one of those that will be executed first 
+      */
+   	CGlxtnTask* Task(const TGlxtnTaskId& aId) const;
+
+    /**
+     * Adds a task to the task list.  If no task is currently running, the task
+     * is started.
+     *
+     * @param aTask Task to add.  Takes ownership, task is deleted if a leave occurs.
+     *
+     * @param aExecutionOrder -if ELastOut, the tast gets added to the bottom 
+     *					  	  of the queue of the tasks with the same priority 
+     * 					      as the new tasks. This means that the task is 
+     *						  executed after the previously added tasks (with 
+     *						  same priority) have been run.
+     *						  -if EFirstOut, the task gets added to the top,
+     *						  and will be executed before the other tasks
+     *						  with the same priority (unless more tasks added 
+     *						  later, of course)
+     */
+    void AddTaskL(CGlxtnTask* aTask, TExecutionOrder aExecutionOrder = ELastOut);
+
+    /**
+     * Cancel all tasks relating to a given media item.
+     * @param aItemId ID of media item.
+     */
+    void CancelTasks(const TGlxMediaId& aItemId);
+
+    /**
+     * Cancel all tasks using a given storage.
+     * @param aClient Reference to thumbnail storage.
+     */
+    void CancelTasks(MGlxtnThumbnailStorage* aStorage);
+
+    /**
+     * Gets the total task count
+     *
+     * @return TInt task count
+     */
+    inline TInt TaskCount() const { return iTasks.Count(); };
+
+protected:
+    /**
+     * Constructors
+     */
+    CGlxtnTaskManager();
+    void ConstructL(); 
+
+private: // From CActive
+	void RunL();		
+	void DoCancel();
+    TInt RunError(TInt aError);
+
+private:
+    /**
+     * Issue a self-completing request causing RunL to be called.
+     */
+    void AsyncRun();
+
+private:
+    /**
+     * Task list in priority order
+     */
+    RPointerArray<CGlxtnTask> iTasks;
+    
+    /**
+     * Task that is currently being run.
+     */
+    CGlxtnTask* iCurrentTask;
+    };
+
+#endif // C_GLXTNTASKMANAGER_H