1/* 2 * Copyright (C) 2013 Apple Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY 14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR 17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY 21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26#ifndef SQLTransactionStateMachine_h 27#define SQLTransactionStateMachine_h 28 29#if ENABLE(SQL_DATABASE) 30 31#include "SQLTransactionState.h" 32#include <wtf/ThreadSafeRefCounted.h> 33 34namespace WebCore { 35 36template<typename T> 37class SQLTransactionStateMachine { 38public: 39 virtual ~SQLTransactionStateMachine() { } 40 41protected: 42 SQLTransactionStateMachine(); 43 44 typedef SQLTransactionState (T::* StateFunction)(); 45 virtual StateFunction stateFunctionFor(SQLTransactionState) = 0; 46 47 void setStateToRequestedState(); 48 void runStateMachine(); 49 50 SQLTransactionState m_nextState; 51 SQLTransactionState m_requestedState; 52 53#ifndef NDEBUG 54 // The state audit trail (i.e. bread crumbs) keeps track of up to the last 55 // s_sizeOfStateAuditTrail states that the state machine enters. The audit 56 // trail is updated before entering each state. This is for debugging use 57 // only. 58 static const int s_sizeOfStateAuditTrail = 20; 59 int m_nextStateAuditEntry; 60 SQLTransactionState m_stateAuditTrail[s_sizeOfStateAuditTrail]; 61#endif 62}; 63 64#if !LOG_DISABLED 65extern const char* nameForSQLTransactionState(SQLTransactionState); 66#endif 67 68template<typename T> 69SQLTransactionStateMachine<T>::SQLTransactionStateMachine() 70 : m_nextState(SQLTransactionState::Idle) 71 , m_requestedState(SQLTransactionState::Idle) 72#ifndef NDEBUG 73 , m_nextStateAuditEntry(0) 74#endif 75{ 76#ifndef NDEBUG 77 for (int i = 0; i < s_sizeOfStateAuditTrail; i++) 78 m_stateAuditTrail[i] = SQLTransactionState::NumberOfStates; 79#endif 80} 81 82template<typename T> 83void SQLTransactionStateMachine<T>::setStateToRequestedState() 84{ 85 ASSERT(m_nextState == SQLTransactionState::Idle); 86 ASSERT(m_requestedState != SQLTransactionState::Idle); 87 m_nextState = m_requestedState; 88 m_requestedState = SQLTransactionState::Idle; 89} 90 91template<typename T> 92void SQLTransactionStateMachine<T>::runStateMachine() 93{ 94 ASSERT(SQLTransactionState::End < SQLTransactionState::Idle); 95 while (m_nextState > SQLTransactionState::Idle) { 96 ASSERT(m_nextState < SQLTransactionState::NumberOfStates); 97 StateFunction stateFunction = stateFunctionFor(m_nextState); 98 ASSERT(stateFunction); 99 100#ifndef NDEBUG 101 m_stateAuditTrail[m_nextStateAuditEntry] = m_nextState; 102 m_nextStateAuditEntry = (m_nextStateAuditEntry + 1) % s_sizeOfStateAuditTrail; 103#endif 104 m_nextState = (static_cast<T*>(this)->*stateFunction)(); 105 } 106} 107 108} // namespace WebCore 109 110#endif // ENABLE(SQL_DATABASE) 111 112#endif // SQLTransactionStateMachine_h 113