Files
rippled/modules/beast_core/threads/beast_SpinLock.h
Vinnie Falco 43e6d345e4 General beast update, fixes, optimizations, features:
* Clean ups, optimizations, and new File::commonDocumentsDirectory enum
* Replace sortArray with std::sort for performance
* More error tolerance in XML parser, speedups
* Refactor some byte-order mark detection code
* Add String::appendCharPointer overloads
* More XML parser optimisations and better error detection
* Misc performance tweaks
* Fixes for support of non utf8 strings
* Increased precision when storing strings in XmlElement
* Minor clean-ups
* Minor fix to XmlDocument
* Cleanups to CriticalSection and related synchronization primitives
* Fix DynamicArray unit test
2013-09-10 10:36:46 -07:00

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//------------------------------------------------------------------------------
/*
This file is part of Beast: https://github.com/vinniefalco/Beast
Copyright 2013, Vinnie Falco <vinnie.falco@gmail.com>
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 BEAST_SPINLOCK_H_INCLUDED
#define BEAST_SPINLOCK_H_INCLUDED
//==============================================================================
/**
A simple spin-lock class that can be used as a simple, low-overhead mutex for
uncontended situations.
Note that unlike a CriticalSection, this type of lock is not re-entrant, and may
be less efficient when used it a highly contended situation, but it's very small and
requires almost no initialisation.
It's most appropriate for simple situations where you're only going to hold the
lock for a very brief time.
@see CriticalSection
*/
class BEAST_API SpinLock : public Uncopyable
{
public:
inline SpinLock() noexcept {}
inline ~SpinLock() noexcept {}
/** Acquires the lock.
This will block until the lock has been successfully acquired by this thread.
Note that a SpinLock is NOT re-entrant, and is not smart enough to know whether the
caller thread already has the lock - so if a thread tries to acquire a lock that it
already holds, this method will never return!
It's strongly recommended that you never call this method directly - instead use the
ScopedLockType class to manage the locking using an RAII pattern instead.
*/
void enter() const noexcept;
/** Attempts to acquire the lock, returning true if this was successful. */
inline bool tryEnter() const noexcept
{
return lock.compareAndSetBool (1, 0);
}
/** Releases the lock. */
inline void exit() const noexcept
{
bassert (lock.value == 1); // Agh! Releasing a lock that isn't currently held!
lock = 0;
}
//==============================================================================
/** Provides the type of scoped lock to use for locking a SpinLock. */
typedef GenericScopedLock <SpinLock> ScopedLockType;
/** Provides the type of scoped unlocker to use with a SpinLock. */
typedef GenericScopedUnlock <SpinLock> ScopedUnlockType;
private:
//==============================================================================
mutable Atomic<int> lock;
};
#endif // BEAST_SPINLOCK_H_INCLUDED