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>
54typedef 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>
69typedef 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. */
87typedef 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. */
105typedef 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
115typedef 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
128struct hb_mutex_t
129{
130 /* TODO Add tracing. */
131
132 hb_mutex_impl_t m;
133
134 void init () { hb_mutex_impl_init (&m); }
135 void lock () { hb_mutex_impl_lock (&m); }
136 void unlock () { hb_mutex_impl_unlock (&m); }
137 void fini () { hb_mutex_impl_finish (&m); }
138};
139
140struct hb_lock_t
141{
142 hb_lock_t (hb_mutex_t &mutex_) : mutex (mutex_) { mutex.lock (); }
143 ~hb_lock_t () { mutex.unlock (); }
144 private:
145 hb_mutex_t &mutex;
146};
147
148
149#endif /* HB_MUTEX_HH */
150