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1 /*
2  * Copyright © 2007  Chris Wilson
3  * Copyright © 2009,2010  Red Hat, Inc.
4  * Copyright © 2011,2012  Google, Inc.
5  *
6  *  This is part of HarfBuzz, a text shaping library.
7  *
8  * Permission is hereby granted, without written agreement and without
9  * license or royalty fees, to use, copy, modify, and distribute this
10  * software and its documentation for any purpose, provided that the
11  * above copyright notice and the following two paragraphs appear in
12  * all copies of this software.
13  *
14  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
15  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
16  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
17  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
18  * DAMAGE.
19  *
20  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
21  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
22  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
23  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
24  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
25  *
26  * Contributor(s):
27  *	Chris Wilson <chris@chris-wilson.co.uk>
28  * Red Hat Author(s): Behdad Esfahbod
29  * Google Author(s): Behdad Esfahbod
30  */
31 
32 #ifndef HB_MUTEX_HH
33 #define HB_MUTEX_HH
34 
35 #include "hb.hh"
36 
37 
38 /* mutex */
39 
40 /* We need external help for these */
41 
42 #if defined(HB_MUTEX_IMPL_INIT) \
43  && defined(hb_mutex_impl_init) \
44  && defined(hb_mutex_impl_lock) \
45  && defined(hb_mutex_impl_unlock) \
46  && defined(hb_mutex_impl_finish)
47 
48 /* Defined externally, i.e. in config.h; must have typedef'ed hb_mutex_impl_t as well. */
49 
50 
51 #elif !defined(HB_NO_MT) && defined(_WIN32)
52 
53 #include <windows.h>
54 typedef CRITICAL_SECTION hb_mutex_impl_t;
55 #define HB_MUTEX_IMPL_INIT	{0}
56 #if defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)
57 #define hb_mutex_impl_init(M)	InitializeCriticalSectionEx (M, 0, 0)
58 #else
59 #define hb_mutex_impl_init(M)	InitializeCriticalSection (M)
60 #endif
61 #define hb_mutex_impl_lock(M)	EnterCriticalSection (M)
62 #define hb_mutex_impl_unlock(M)	LeaveCriticalSection (M)
63 #define hb_mutex_impl_finish(M)	DeleteCriticalSection (M)
64 
65 
66 #elif !defined(HB_NO_MT) && (defined(HAVE_PTHREAD) || defined(__APPLE__))
67 
68 #include <pthread.h>
69 typedef pthread_mutex_t hb_mutex_impl_t;
70 #define HB_MUTEX_IMPL_INIT	PTHREAD_MUTEX_INITIALIZER
71 #define hb_mutex_impl_init(M)	pthread_mutex_init (M, nullptr)
72 #define hb_mutex_impl_lock(M)	pthread_mutex_lock (M)
73 #define hb_mutex_impl_unlock(M)	pthread_mutex_unlock (M)
74 #define hb_mutex_impl_finish(M)	pthread_mutex_destroy (M)
75 
76 
77 #elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)
78 
79 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
80 # include <sched.h>
81 # define HB_SCHED_YIELD() sched_yield ()
82 #else
83 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END
84 #endif
85 
86 /* This actually is not a totally awful implementation. */
87 typedef volatile int hb_mutex_impl_t;
88 #define HB_MUTEX_IMPL_INIT	0
89 #define hb_mutex_impl_init(M)	*(M) = 0
90 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (__sync_lock_test_and_set((M), 1)) HB_SCHED_YIELD (); } HB_STMT_END
91 #define hb_mutex_impl_unlock(M)	__sync_lock_release (M)
92 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
93 
94 
95 #elif !defined(HB_NO_MT)
96 
97 #if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
98 # include <sched.h>
99 # define HB_SCHED_YIELD() sched_yield ()
100 #else
101 # define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END
102 #endif
103 
104 #define HB_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */
105 typedef volatile int hb_mutex_impl_t;
106 #define HB_MUTEX_IMPL_INIT	0
107 #define hb_mutex_impl_init(M)	*(M) = 0
108 #define hb_mutex_impl_lock(M)	HB_STMT_START { while (*(M)) HB_SCHED_YIELD (); (*(M))++; } HB_STMT_END
109 #define hb_mutex_impl_unlock(M)	(*(M))--;
110 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
111 
112 
113 #else /* HB_NO_MT */
114 
115 typedef int hb_mutex_impl_t;
116 #define HB_MUTEX_IMPL_INIT	0
117 #define hb_mutex_impl_init(M)	HB_STMT_START {} HB_STMT_END
118 #define hb_mutex_impl_lock(M)	HB_STMT_START {} HB_STMT_END
119 #define hb_mutex_impl_unlock(M)	HB_STMT_START {} HB_STMT_END
120 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
121 
122 
123 #endif
124 
125 
126 #define HB_MUTEX_INIT		{HB_MUTEX_IMPL_INIT}
127 
128 struct hb_mutex_t
129 {
130   /* TODO Add tracing. */
131 
132   hb_mutex_impl_t m;
133 
inithb_mutex_t134   void init   () { hb_mutex_impl_init   (&m); }
lockhb_mutex_t135   void lock   () { hb_mutex_impl_lock   (&m); }
unlockhb_mutex_t136   void unlock () { hb_mutex_impl_unlock (&m); }
finihb_mutex_t137   void fini ()   { hb_mutex_impl_finish (&m); }
138 };
139 
140 struct hb_lock_t
141 {
hb_lock_thb_lock_t142   hb_lock_t (hb_mutex_t &mutex_) : mutex (mutex_) { mutex.lock (); }
~hb_lock_thb_lock_t143   ~hb_lock_t () { mutex.unlock (); }
144   private:
145   hb_mutex_t &mutex;
146 };
147 
148 
149 #endif /* HB_MUTEX_HH */
150