Differential D20326 Diff 55629 src/server/storage/dbdeadlockcatcher.h

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src/server/storage/dbdeadlockcatcher.h

  • This file was copied from src/server/storage/dbexception.h.
1/* 1​/*
2 Copyright (c) 2012 Volker Krause <vkrause@kde.org> 2​ Copyright (c) 2019 David Faure <faure@kde.org>
3 3​
4 This library is free software; you can redistribute it and/or modify it 4​ This library is free software; you can redistribute it and/or modify it
5 under the terms of the GNU Library General Public License as published by 5​ under the terms of the GNU Library General Public License as published by
6 the Free Software Foundation; either version 2 of the License, or (at your 6​ the Free Software Foundation; either version 2 of the License, or (at your
7 option) any later version. 7​ option) any later version.
8 8​
9 This library is distributed in the hope that it will be useful, but WITHOUT 9​ This library is distributed in the hope that it will be useful, but WITHOUT
10 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10​ ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public 11​ FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public
12 License for more details. 12​ License for more details.
13 13​
14 You should have received a copy of the GNU Library General Public License 14​ You should have received a copy of the GNU Library General Public License
15 along with this library; see the file COPYING.LIB. If not, write to the 15​ along with this library; see the file COPYING.LIB. If not, write to the
16 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 16​ Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 02110-1301, USA. 17​ 02110-1301, USA.
18*/ 18​*/
19 19​
20#ifndef DBEXCEPTION_H 20​#ifndef AKONADI_DBDEADLOCKCATCHER_H
21#define DBEXCEPTION_H 21​#define AKONADI_DBDEADLOCKCATCHER_H
22 22​
23#include "exception.h" 23​#include "dbexception.h"
24 ​
25class QSqlQuery; ​
26 24​
27namespace Akonadi 25​namespace Akonadi
28{ 26​{
27​
29namespace Server 28​namespace Server
30{ 29​{
31 30​
32/** Exception for reporting SQL errors. */ 31​/**
33class DbException : public Exception 32​ This class catches DbDeadlockException (as emitted by QueryBuilder)
33​ and retries execution of the method when it happens, as required by
34​ SQL databases.
35​*/
36​class DbDeadlockCatcher
34{ 37​{
35public: 38​public:
36 explicit DbException(const QSqlQuery &query, const char *what = nullptr); 39​ template <typename Func>
37 const char *type() const throw() override; 40​ explicit DbDeadlockCatcher(Func &&func) { callFunc(func, 0); }
41​
42​private:
43​ static const int MaxRecursion = 5;
44​ template <typename Func>
45​ void callFunc(Func &&func, int recursionCounter) {
46​ try {
47​ func();
48​ } catch(const DbDeadlockException &) {
dvratilUnsubmitted
Not Done

Use a named constant instead of a magic number.

dvratil: Use a named constant instead of a magic number.
49​ if (recursionCounter == MaxRecursion) {
50​ throw;
51​ } else {
52​ callFunc(func, ++recursionCounter); // recurse
53​ }
54​ }
55​ }
38}; 56​};
39 57​
40} // namespace Server 58​} // namespace Server
41} // namespace Akonadi 59​} // namespace Akonadi
42 60​
43#endif // DBEXCEPTION_H 61​#endif