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 | #pragma once |
27 | |
28 | #include "SQLTransactionState.h" |
29 | |
30 | namespace WebCore { |
31 | |
32 | template<typename T> |
33 | class SQLTransactionStateMachine { |
34 | public: |
35 | virtual ~SQLTransactionStateMachine() = default; |
36 | |
37 | protected: |
38 | SQLTransactionStateMachine(); |
39 | |
40 | typedef void (T::*StateFunction)(); |
41 | virtual StateFunction stateFunctionFor(SQLTransactionState) = 0; |
42 | |
43 | void setStateToRequestedState(); |
44 | void runStateMachine(); |
45 | |
46 | SQLTransactionState m_nextState; |
47 | SQLTransactionState m_requestedState; |
48 | |
49 | #ifndef NDEBUG |
50 | // The state audit trail (i.e. bread crumbs) keeps track of up to the last |
51 | // s_sizeOfStateAuditTrail states that the state machine enters. The audit |
52 | // trail is updated before entering each state. This is for debugging use |
53 | // only. |
54 | static const int s_sizeOfStateAuditTrail = 20; |
55 | int m_nextStateAuditEntry; |
56 | SQLTransactionState m_stateAuditTrail[s_sizeOfStateAuditTrail]; |
57 | #endif |
58 | }; |
59 | |
60 | #if !LOG_DISABLED |
61 | extern const char* nameForSQLTransactionState(SQLTransactionState); |
62 | #endif |
63 | |
64 | template<typename T> |
65 | SQLTransactionStateMachine<T>::SQLTransactionStateMachine() |
66 | : m_nextState(SQLTransactionState::Idle) |
67 | , m_requestedState(SQLTransactionState::Idle) |
68 | #ifndef NDEBUG |
69 | , m_nextStateAuditEntry(0) |
70 | #endif |
71 | { |
72 | #ifndef NDEBUG |
73 | for (int i = 0; i < s_sizeOfStateAuditTrail; i++) |
74 | m_stateAuditTrail[i] = SQLTransactionState::NumberOfStates; |
75 | #endif |
76 | } |
77 | |
78 | template<typename T> |
79 | void SQLTransactionStateMachine<T>::setStateToRequestedState() |
80 | { |
81 | ASSERT(m_nextState == SQLTransactionState::Idle); |
82 | ASSERT(m_requestedState != SQLTransactionState::Idle); |
83 | m_nextState = m_requestedState; |
84 | m_requestedState = SQLTransactionState::Idle; |
85 | } |
86 | |
87 | template<typename T> |
88 | void SQLTransactionStateMachine<T>::runStateMachine() |
89 | { |
90 | ASSERT(SQLTransactionState::End < SQLTransactionState::Idle); |
91 | |
92 | if (m_nextState <= SQLTransactionState::Idle) |
93 | return; |
94 | |
95 | ASSERT(m_nextState < SQLTransactionState::NumberOfStates); |
96 | |
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 | |
105 | (static_cast<T*>(this)->*stateFunction)(); |
106 | m_nextState = SQLTransactionState::Idle; |
107 | } |
108 | |
109 | } // namespace WebCore |
110 | |