diff -r 61bc0f252b2b -r bac7acad7cb3 camerauis/cameraxui/cxengine/inc/cxestatemachinebase.h --- a/camerauis/cameraxui/cxengine/inc/cxestatemachinebase.h Tue Aug 31 15:03:46 2010 +0300 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,133 +0,0 @@ -/* -* Copyright (c) 2009-2010 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: -* -*/ - -#ifndef CXESTATEMACHINEBASE_H -#define CXESTATEMACHINEBASE_H - -#include -#include -#include "cxeerror.h" - -class CxeState; - -/** -* CxeStateMachineBase is used as the base class for all finite state machines in the -* engine. It's not a fully functional state machine in the sense that it does not provide any -* mechanism for handling events that would trigged state changes. Instead, -* it relies on the derived class to call setState() whenever the state -* should change. The derived class should also provide a list of states -* and allowed transitions so that CxeStateMachineBase can verify that each state -* change is valid. A pure virtual function, handleStateChanged() should be -* implemented by derived classes to handle notifing other interested objects about -* the state change. This class cannot emit the signals itself, because it does not -* derived from QObject and it handles all state IDs as plain integers instead of the -* preferred class specific enumerations. -* -* CxeStateMachineBase does not derive from QObject to make easier for the engine -* control implementation classes to derive from it. Additionally we avoid the overhead -* brought by QObject. -* -* CxeStateMachineBase class is to be used for unit testing. Engine class should derive -* from CxeStateMachine class. -*/ - -class CxeStateMachineBase -{ -public: - /** - * CxeStateMachine constructor. - * @sa addState setInitialState - * @param stateMachineName Name for this state machine (used for debug prints) - */ - CxeStateMachineBase(const char *stateMachineName); - virtual ~CxeStateMachineBase(); - -protected: - /** - * Add a new state to the machine. Takes ownership of state. - * - * @param state A CxeState object defining a name, ID, and allowed transitions for the - * new state. The CxeState ID must be unique and not to contain overlapping bits with other - * state ids, since bitwise AND operator is used for the state ids. - * @return False if adding failed due to incorrect id. - */ - virtual bool addState(CxeState *state); - - /** - * Initiate a state transition from current state to a given state ID. In cases that - * current state is same as the new state, method returns without doing anything. If the state - * transition is invalid, this function return false. - * - * @param stateId State ID of the new state - * @param error Optional error code to be associated with the transition - * @return False if state change fails. True if changing is allowed, or the current state is same - * as the new state. - */ - virtual bool setState(int stateId, CxeError::Id error = CxeError::None); - - /** - * Set the initial state of the state machine. Can be called only once. - * This method will panic, if initial state is unknown, or initial state has already - * been set. - * - * @param stateId State ID for the initial state. - * @return False if state to be set intial state is not known, or initial - * state has already been set. - */ - virtual bool setInitialState(int stateId); - - /** - * Pure virtual function to be implemented by derived classes. Called when state changes. - * The implementation should emit a signal informing interested parties of a state change. - * - * @param newStateId State ID for the new state - * @param error An error code associated with the state transition - */ - virtual void handleStateChanged(int newStateId, CxeError::Id error) = 0; - - /** - * Get current state ID. It is recommended for derived classes to create - * a new method (typically called state()) which returns the current state ID - * typecasted into a class specific enumeration. - * @return Current state ID - */ - int stateId() const; - - /** - * Verify if a state transition is possible. - * @param newStateId State ID of the new state. - * @return Whether state transition is possible. - */ - bool verifyStateChange(int newStateId); - -private: - - //! Hash table of all states. stateId as key - QHash mStates; - - //! All states ORed together - int mStateBitsUsed; - - //! Current state - int mStateId; - - //! Name of this state machine (for debug prints) - QString mName; - -}; - -#endif // CXESTATEMACHINEBASE_H