Files
xahaud/src/ripple/basics/ScopedLock.h
Howard Hinnant 595912f82d Remove unused GenericScopedLock and GenericScopedTryLock.
* Update documentation of GenericScopedUnlock.
2016-05-10 17:38:38 -04:00

106 lines
3.3 KiB
C++

//------------------------------------------------------------------------------
/*
This file is part of rippled: https://github.com/ripple/rippled
Copyright (c) 2012, 2013 Ripple Labs Inc.
Portions of this file are from JUCE.
Copyright (c) 2013 - Raw Material Software Ltd.
Please visit http://www.juce.com
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL , DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
//==============================================================================
#ifndef RIPPLE_BASICS_SCOPEDLOCK_H_INCLUDED
#define RIPPLE_BASICS_SCOPEDLOCK_H_INCLUDED
namespace ripple
{
//==============================================================================
/**
Automatically unlocks and re-locks a mutex object.
This is the reverse of a std::lock_guard object - instead of locking the mutex
for the lifetime of this object, it unlocks it.
Make sure you don't try to unlock mutexes that aren't actually locked!
e.g. @code
std::mutex mut;
for (;;)
{
std::lock_guard<std::mutex> myScopedLock{mut};
// mut is now locked
... do some stuff with it locked ..
while (xyz)
{
... do some stuff with it locked ..
GenericScopedUnlock<std::mutex> unlocker{mut};
// mut is now unlocked for the remainder of this block,
// and re-locked at the end.
...do some stuff with it unlocked ...
} // mut gets locked here.
} // mut gets unlocked here
@endcode
*/
template <class MutexType>
class GenericScopedUnlock
{
MutexType& lock_;
public:
/** Creates a GenericScopedUnlock.
As soon as it is created, this will unlock the CriticalSection, and
when the ScopedLock object is deleted, the CriticalSection will
be re-locked.
Make sure this object is created and deleted by the same thread,
otherwise there are no guarantees what will happen! Best just to use it
as a local stack object, rather than creating one with the new() operator.
*/
explicit GenericScopedUnlock (MutexType& lock) noexcept
: lock_ (lock)
{
lock.unlock();
}
GenericScopedUnlock (GenericScopedUnlock const&) = delete;
GenericScopedUnlock& operator= (GenericScopedUnlock const&) = delete;
/** Destructor.
The CriticalSection will be unlocked when the destructor is called.
Make sure this object is created and deleted by the same thread,
otherwise there are no guarantees what will happen!
*/
~GenericScopedUnlock() noexcept(false)
{
lock_.lock();
}
};
} // ripple
#endif