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create/src/App/AutoTransaction.h
wmayer 749361d2f3 App: modernize C++11
* use nullptr
2022-03-23 17:29:23 +01:00

134 lines
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C++

/****************************************************************************
* Copyright (c) 2019 Zheng Lei (realthunder) <realthunder.dev@gmail.com> *
* *
* This file is part of the FreeCAD CAx development system. *
* *
* This library is free software; you can redistribute it and/or *
* modify it under the terms of the GNU Library General Public *
* License as published by the Free Software Foundation; either *
* version 2 of the License, or (at your option) any later version. *
* *
* This library is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU Library General Public License for more details. *
* *
* You should have received a copy of the GNU Library General Public *
* License along with this library; see the file COPYING.LIB. If not, *
* write to the Free Software Foundation, Inc., 59 Temple Place, *
* Suite 330, Boston, MA 02111-1307, USA *
* *
****************************************************************************/
#ifndef APP_AUTOTRANSACTION_H
#define APP_AUTOTRANSACTION_H
#include <cstddef>
namespace App {
class Application;
/// Helper class to manager transaction (i.e. undo/redo)
class AppExport AutoTransaction {
private:
/// Private new operator to prevent heap allocation
void* operator new (std::size_t) = delete;
public:
/** Constructor
*
* @param name: optional new transaction name on construction
* @param tmpName: if true and a new transaction is setup, the name given is
* considered as temporary, and subsequent construction of this class (or
* calling Application::setActiveTransaction()) can override the transaction
* name.
*
* The constructor increments an internal counter
* (Application::_activeTransactionGuard). The counter prevents any new
* active transaction being setup. It also prevents close (i.e. commits) the
* current active transaction until it reaches zero. It does not have any
* effect on aborting transaction, though.
*/
AutoTransaction(const char *name=nullptr, bool tmpName=false);
/** Destructor
*
* This destructor decrease an internal counter
* (Application::_activeTransactionGuard), and will commit any current
* active transaction when the counter reaches zero.
*/
~AutoTransaction();
/** Close or abort the transaction
*
* This function can be used to explicitly close (i.e. commit) the
* transaction, if the current transaction ID matches the one created inside
* the constructor. For aborting, it will abort any current transaction
*/
void close(bool abort=false);
/** Enable/Disable any AutoTransaction instance in the current stack
*
* Once disabled, any empty temporary named transaction is closed. If there
* are non-empty or non-temporary named active transaction, it will not be
* auto closed.
*
* This function may be used in, for example, Gui::Document::setEdit() to
* allow a transaction live past any command scope.
*/
static void setEnable(bool enable);
private:
int tid = 0;
};
/** Helper class to lock a transaction from being closed or aborted.
*
* The helper class is used to protect some critical transaction from being
* closed prematurely, e.g. when deleting some object.
*/
class AppExport TransactionLocker {
public:
/** Constructor
* @param lock: whether to activate the lock
*/
TransactionLocker(bool lock=true);
/** Destructor
* Unlock the transaction is this locker is active
*/
~TransactionLocker();
/** Activate or deactivate this locker
* @param enable: whether to activate the locker
*
* An internal counter is used to support recursive locker. When activated,
* the current active transaction cannot be closed or aborted. But the
* closing call (Application::closeActiveTransaction()) will be remembered,
* and performed when the internal lock counter reaches zero.
*/
void activate(bool enable);
/// Check if the locker is active
bool isActive() const {return active;}
/// Check if transaction is being locked
static bool isLocked();
friend class Application;
private:
/// Private new operator to prevent heap allocation
void* operator new (std::size_t) = delete;
private:
bool active;
};
} // namespace App
#endif // APP_AUTOTRANSACTION_H