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 */
22static __attribute__((always_inline)) int32_t sk_atomic_inc(int32_t *addr) {
23    return __sync_fetch_and_add(addr, 1);
24}
25
26static __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*/
47SK_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*/
52SK_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//
65struct SkBaseMutex {
66    void    acquire() { pthread_mutex_lock(&fMutex); }
67    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.
82class SkMutex : public SkBaseMutex, SkNoncopyable {
83public:
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//
93class SkMutex : SkNoncopyable {
94public:
95    SkMutex();
96    ~SkMutex();
97
98    void    acquire();
99    void    release();
100
101private:
102    bool fIsGlobal;
103    enum {
104        kStorageIntCount = 64
105    };
106    uint32_t    fStorage[kStorageIntCount];
107};
108
109typedef 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