xref: /aoo41x/main/framework/inc/threadhelp/irwlock.h (revision cdf0e10c)
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27 
28 #ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_
29 #define __FRAMEWORK_THREADHELP_IRWLOCK_H_
30 
31 //_________________________________________________________________________________________________________________
32 //	includes
33 //_________________________________________________________________________________________________________________
34 
35 //_________________________________________________________________________________________________________________
36 //	namespace
37 //_________________________________________________________________________________________________________________
38 
39 namespace framework{
40 
41 //_________________________________________________________________________________________________________________
42 //	declarations
43 //_________________________________________________________________________________________________________________
44 
45 /*-************************************************************************************************************//**
46 	@descr			A guard (specialy a write guard) support different internal working states.
47 					His lock can set for reading or writing/reading! Or he was unlocked by user ...
48 *//*-*************************************************************************************************************/
49 enum ELockMode
50 {
51 	E_NOLOCK	,
52 	E_READLOCK	,
53 	E_WRITELOCK
54 };
55 
56 /*-************************************************************************************************************//**
57 	@descr			We implement two guards for using an rw-lock. But if you wish to implement
58 					different rw-locks to you will have problems by using with same guard implementation!
59 					Thats why we define this "pure virtual base class" ...
60 					All rw-locks must support this base interface for working and all guard must use this one too!
61 *//*-*************************************************************************************************************/
62 class IRWLock
63 {
64 	//-------------------------------------------------------------------------------------------------------------
65 	//	public methods
66 	//-------------------------------------------------------------------------------------------------------------
67 	public:
68 
69 		/*-****************************************************************************************************//**
70 			@descr		These functions must be supported by a derived class!
71 							acquireReadAccess()		-try to register thread as reader
72 							releaseReadAccess()		-unregister thread as reader
73 							acquireWriteAccess()	-try to register thread as writer
74 							releaseWriteAccess()	-unregister thread as writer
75 							downgradeWriteAccess()	-make writer to reader
76 		*//*-*****************************************************************************************************/
77         virtual void acquireReadAccess    () =0;
78         virtual void releaseReadAccess    () =0;
79         virtual void acquireWriteAccess   () =0;
80         virtual void releaseWriteAccess   () =0;
81         virtual void downgradeWriteAccess () =0;
82 
83 };		//	class IRWLock
84 
85 }		//	namespace framework
86 
87 #endif	//	#ifndef __FRAMEWORK_THREADHELP_IRWLOCK_H_
88