1 /*
2  *  Copyright (C) 2005-2018 Team Kodi
3  *  This file is part of Kodi - https://kodi.tv
4  *
5  *  SPDX-License-Identifier: GPL-2.0-or-later
6  *  See LICENSES/README.md for more information.
7  */
8 
9 #pragma once
10 
11 #include "threads/Condition.h"
12 #include "threads/Helpers.h"
13 #include "threads/SingleLock.h"
14 
15 /**
16  * A CSharedSection is a mutex that satisfies the Shared Lockable concept (see Lockables.h).
17  */
18 class CSharedSection
19 {
20   CCriticalSection sec;
21   XbmcThreads::ConditionVariable actualCv;
22   XbmcThreads::TightConditionVariable<XbmcThreads::InversePredicate<unsigned int&> > cond;
23 
24   unsigned int sharedCount = 0;
25 
26 public:
CSharedSection()27   inline CSharedSection() : cond(actualCv,XbmcThreads::InversePredicate<unsigned int&>(sharedCount)) {}
28 
lock()29   inline void lock() { CSingleLock l(sec); while (sharedCount) cond.wait(l); sec.lock(); }
try_lock()30   inline bool try_lock() { return (sec.try_lock() ? ((sharedCount == 0) ? true : (sec.unlock(), false)) : false); }
unlock()31   inline void unlock() { sec.unlock(); }
32 
lock_shared()33   inline void lock_shared() { CSingleLock l(sec); sharedCount++; }
try_lock_shared()34   inline bool try_lock_shared() { return (sec.try_lock() ? sharedCount++, sec.unlock(), true : false); }
unlock_shared()35   inline void unlock_shared() { CSingleLock l(sec); sharedCount--; if (!sharedCount) { cond.notifyAll(); } }
36 };
37 
38 class CSharedLock : public XbmcThreads::SharedLock<CSharedSection>
39 {
40 public:
CSharedLock(CSharedSection & cs)41   inline explicit CSharedLock(CSharedSection& cs) : XbmcThreads::SharedLock<CSharedSection>(cs) {}
42 
IsOwner()43   inline bool IsOwner() const { return owns_lock(); }
Enter()44   inline void Enter() { lock(); }
Leave()45   inline void Leave() { unlock(); }
46 };
47 
48 class CExclusiveLock : public XbmcThreads::UniqueLock<CSharedSection>
49 {
50 public:
CExclusiveLock(CSharedSection & cs)51   inline explicit CExclusiveLock(CSharedSection& cs) : XbmcThreads::UniqueLock<CSharedSection>(cs) {}
52 
IsOwner()53   inline bool IsOwner() const { return owns_lock(); }
Leave()54   inline void Leave() { unlock(); }
Enter()55   inline void Enter() { lock(); }
56 };
57 
58