1 // @(#)root/base:$Id$
2 // Author: Fons Rademakers 14/07/2002
3
4 /*************************************************************************
5 * Copyright (C) 1995-2002, Rene Brun and Fons Rademakers. *
6 * All rights reserved. *
7 * *
8 * For the licensing terms see $ROOTSYS/LICENSE. *
9 * For the list of contributors see $ROOTSYS/README/CREDITS. *
10 *************************************************************************/
11
12 #ifndef ROOT_TVirtualMutex
13 #define ROOT_TVirtualMutex
14
15
16 //////////////////////////////////////////////////////////////////////////
17 // //
18 // TVirtualMutex //
19 // //
20 // This class implements a mutex interface. The actual work is done via //
21 // TMutex which is available as soon as the thread library is loaded. //
22 // //
23 //////////////////////////////////////////////////////////////////////////
24
25 #ifndef ROOT_TObject
26 #include "TObject.h"
27 #endif
28
29 class TVirtualMutex;
30
31 // Global mutex set in TThread::Init
32 R__EXTERN TVirtualMutex *gGlobalMutex;
33
34 class TVirtualMutex : public TObject {
35
36 public:
37 TVirtualMutex(Bool_t /* recursive */ = kFALSE) { }
38 virtual ~TVirtualMutex() { }
39
40 virtual Int_t Lock() = 0;
41 virtual Int_t TryLock() = 0;
42 virtual Int_t UnLock() = 0;
43 virtual Int_t CleanUp() = 0;
44 Int_t Acquire() { return Lock(); }
45 Int_t Release() { return UnLock(); }
46
47 virtual TVirtualMutex *Factory(Bool_t /*recursive*/ = kFALSE) = 0;
48
49 ClassDef(TVirtualMutex,0) // Virtual mutex lock class
50 };
51
52
53 //////////////////////////////////////////////////////////////////////////
54 // //
55 // TLockGuard //
56 // //
57 // This class provides mutex resource management in a guaranteed and //
58 // exception safe way. Use like this: //
59 // { //
60 // TLockGuard guard(mutex); //
61 // ... // do something //
62 // } //
63 // when guard goes out of scope the mutex is unlocked in the TLockGuard //
64 // destructor. The exception mechanism takes care of calling the dtors //
65 // of local objects so it is exception safe. //
66 // //
67 //////////////////////////////////////////////////////////////////////////
68
69 class TLockGuard {
70
71 private:
72 TVirtualMutex *fMutex;
73
74 TLockGuard(const TLockGuard&); // not implemented
75 TLockGuard& operator=(const TLockGuard&); // not implemented
76
77 public:
78 TLockGuard(TVirtualMutex *mutex)
79 : fMutex(mutex) { if (fMutex) fMutex->Lock(); }
80 virtual ~TLockGuard() { if (fMutex) fMutex->UnLock(); }
81
82 ClassDef(TLockGuard,0) // Exception safe locking/unlocking of mutex
83 };
84
85 // Zero overhead macros in case not compiled with thread support
86 #if defined (_REENTRANT) || defined (WIN32)
87 #define R__LOCKGUARD(mutex) TLockGuard _R__UNIQUE_(R__guard)(mutex)
88 #define R__LOCKGUARD2(mutex) \
89 if (gGlobalMutex && !mutex) { \
90 gGlobalMutex->Lock(); \
91 if (!mutex) \
92 mutex = gGlobalMutex->Factory(kTRUE); \
93 gGlobalMutex->UnLock(); \
94 } \
95 R__LOCKGUARD(mutex)
96 #else
97 #define R__LOCKGUARD(mutex) if (mutex) { }
98 #define R__LOCKGUARD2(mutex) if (mutex) { }
99 #endif
100
101 #endif
102