1
2 /*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10 #ifndef SkThread_platform_DEFINED
11 #define SkThread_platform_DEFINED
12
13 #if defined(SK_BUILD_FOR_ANDROID)
14
15 #if defined(SK_BUILD_FOR_ANDROID_NDK)
16
17 #include <stdint.h>
18
19 /* Just use the GCC atomic intrinsics. They're supported by the NDK toolchain,
20 * have reasonable performance, and provide full memory barriers
21 */
sk_atomic_inc(int32_t * addr)22 static __attribute__((always_inline)) int32_t sk_atomic_inc(int32_t *addr) {
23 return __sync_fetch_and_add(addr, 1);
24 }
25
sk_atomic_dec(int32_t * addr)26 static __attribute__((always_inline)) int32_t sk_atomic_dec(int32_t *addr) {
27 return __sync_fetch_and_add(addr, -1);
28 }
29
30 #else // !SK_BUILD_FOR_ANDROID_NDK
31
32 /* The platform atomics operations are slightly more efficient than the
33 * GCC built-ins, so use them.
34 */
35 #include <utils/Atomic.h>
36
37 #define sk_atomic_inc(addr) android_atomic_inc(addr)
38 #define sk_atomic_dec(addr) android_atomic_dec(addr)
39
40 #endif // !SK_BUILD_FOR_ANDROID_NDK
41
42 #else // !SK_BUILD_FOR_ANDROID
43
44 /** Implemented by the porting layer, this function adds 1 to the int specified
45 by the address (in a thread-safe manner), and returns the previous value.
46 */
47 SK_API int32_t sk_atomic_inc(int32_t* addr);
48 /** Implemented by the porting layer, this function subtracts 1 to the int
49 specified by the address (in a thread-safe manner), and returns the previous
50 value.
51 */
52 SK_API int32_t sk_atomic_dec(int32_t* addr);
53
54 #endif // !SK_BUILD_FOR_ANDROID
55
56 #ifdef SK_USE_POSIX_THREADS
57
58 #include <pthread.h>
59
60 // A SkBaseMutex is a POD structure that can be directly initialized
61 // at declaration time with SK_DECLARE_STATIC/GLOBAL_MUTEX. This avoids the
62 // generation of a static initializer in the final machine code (and
63 // a corresponding static finalizer).
64 //
65 struct SkBaseMutex {
acquireSkBaseMutex66 void acquire() { pthread_mutex_lock(&fMutex); }
releaseSkBaseMutex67 void release() { pthread_mutex_unlock(&fMutex); }
68 pthread_mutex_t fMutex;
69 };
70
71 // Using POD-style initialization prevents the generation of a static initializer
72 // and keeps the acquire() implementation small and fast.
73 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name = { PTHREAD_MUTEX_INITIALIZER }
74
75 // Special case used when the static mutex must be available globally.
76 #define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name = { PTHREAD_MUTEX_INITIALIZER }
77
78 #define SK_DECLARE_MUTEX_ARRAY(name, count) SkBaseMutex name[count] = { PTHREAD_MUTEX_INITIALIZER }
79
80 // A normal mutex that requires to be initialized through normal C++ construction,
81 // i.e. when it's a member of another class, or allocated on the heap.
82 class SkMutex : public SkBaseMutex, SkNoncopyable {
83 public:
84 SkMutex();
85 ~SkMutex();
86 };
87
88 #else // !SK_USE_POSIX_THREADS
89
90 // In the generic case, SkBaseMutex and SkMutex are the same thing, and we
91 // can't easily get rid of static initializers.
92 //
93 class SkMutex : SkNoncopyable {
94 public:
95 SkMutex();
96 ~SkMutex();
97
98 void acquire();
99 void release();
100
101 private:
102 bool fIsGlobal;
103 enum {
104 kStorageIntCount = 64
105 };
106 uint32_t fStorage[kStorageIntCount];
107 };
108
109 typedef SkMutex SkBaseMutex;
110
111 #define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name
112 #define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name
113 #define SK_DECLARE_MUTEX_ARRAY(name, count) SkBaseMutex name[count]
114
115 #endif // !SK_USE_POSIX_THREADS
116
117
118 #endif
119