xref: /aoo42x/main/sal/osl/os2/mutex.c (revision 647f063d)
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21 
22 
23 
24 #include <sys/fmutex.h>
25 
26 #include "system.h"
27 
28 #include <osl/mutex.h>
29 #include <osl/diagnose.h>
30 
31 /*
32     Implementation notes:
33     The void* hidden by oslMutex points to an OS/2 mutex semaphore.
34 */
35 typedef struct _oslMutexImpl {
36 	HMTX				m_Mutex;
37 	int 				m_Locks;
38 	ULONG				m_Owner;
39 	ULONG				m_Requests;
40 } oslMutexImpl;
41 
42 // static mutex to control access to private members of oslMutexImpl
43 static HMTX MutexLock = 0;
44 
45 /*****************************************************************************/
46 /* osl_createMutex */
47 /*****************************************************************************/
osl_createMutex()48 oslMutex SAL_CALL osl_createMutex()
49 {
50 	oslMutexImpl *pMutexImpl;
51     HMTX hMutex;
52     APIRET rc;
53 
54 	pMutexImpl= (oslMutexImpl*)calloc(sizeof(oslMutexImpl), 1);
55 	OSL_ASSERT(pMutexImpl); /* alloc successful? */
56 
57     /* create semaphore */
58     rc = DosCreateMutexSem( NULL, &pMutexImpl->m_Mutex, 0, FALSE );
59     if( rc != 0 )
60 	{
61 		free(pMutexImpl);
62         return NULL;
63 	}
64 
65 	// create static mutex for private members
66 	if (MutexLock == 0)
67 		DosCreateMutexSem( NULL, &MutexLock, 0, FALSE );
68 
69 	return (oslMutex)pMutexImpl;
70 }
71 
72 /*****************************************************************************/
73 /* osl_destroyMutex */
74 /*****************************************************************************/
osl_destroyMutex(oslMutex Mutex)75 void SAL_CALL osl_destroyMutex(oslMutex Mutex)
76 {
77 	oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
78 	if (pMutexImpl)
79 	{
80 		DosCloseMutexSem( pMutexImpl->m_Mutex);
81 		free(pMutexImpl);
82 	}
83 }
84 
85 /*****************************************************************************/
86 /* osl_acquireMutex */
87 /*****************************************************************************/
osl_acquireMutex(oslMutex Mutex)88 sal_Bool SAL_CALL osl_acquireMutex(oslMutex Mutex)
89 {
90 	oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
91     APIRET rc = 0;
92     OSL_ASSERT(Mutex);
93 
94 	DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
95 	pMutexImpl->m_Requests++;
96 	DosReleaseMutexSem( MutexLock);
97 
98 	rc = DosRequestMutexSem( pMutexImpl->m_Mutex, SEM_INDEFINITE_WAIT );
99 
100 	DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
101 	pMutexImpl->m_Requests--;
102 	if (pMutexImpl->m_Locks++ == 0)
103 		pMutexImpl->m_Owner = _gettid();
104 	DosReleaseMutexSem( MutexLock);
105 
106     return( rc == 0 );
107 }
108 
109 /*****************************************************************************/
110 /* osl_tryToAcquireMutex */
111 /*****************************************************************************/
osl_tryToAcquireMutex(oslMutex Mutex)112 sal_Bool SAL_CALL osl_tryToAcquireMutex(oslMutex Mutex)
113 {
114 	sal_Bool 	 ret = sal_False;
115 	oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
116     OSL_ASSERT(Mutex);
117 
118 	DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
119 
120 	if ( ((pMutexImpl->m_Requests == 0) && (pMutexImpl->m_Locks == 0)) ||
121 		 (pMutexImpl->m_Owner == _gettid()) )
122 		ret = osl_acquireMutex(Mutex);
123 
124 	DosReleaseMutexSem( MutexLock);
125 
126     return ret;
127 }
128 
129 /*****************************************************************************/
130 /* osl_releaseMutex */
131 /*****************************************************************************/
osl_releaseMutex(oslMutex Mutex)132 sal_Bool SAL_CALL osl_releaseMutex(oslMutex Mutex)
133 {
134 	oslMutexImpl *pMutexImpl = (oslMutexImpl *)Mutex;
135     APIRET rc;
136     OSL_ASSERT(Mutex);
137 
138 	DosRequestMutexSem( MutexLock, SEM_INDEFINITE_WAIT );
139 
140 	if (--(pMutexImpl->m_Locks) == 0)
141 		pMutexImpl->m_Owner = 0;
142 
143 	DosReleaseMutexSem( MutexLock);
144 
145     rc = DosReleaseMutexSem( pMutexImpl->m_Mutex);
146 
147     return sal_True;
148 }
149 
150 
151 
152 /*****************************************************************************/
153 /* osl_getGlobalMutex */
154 /*****************************************************************************/
155 
156 oslMutex g_Mutex = NULL;
157 
osl_getGlobalMutex(void)158 oslMutex * SAL_CALL osl_getGlobalMutex(void)
159 {
160 	if (g_Mutex == NULL)
161 		g_Mutex = osl_createMutex();
162 	return &g_Mutex;
163 }
164