SkMutex_pthread.h revision d9947f605a335363b0a0541d6d8cb7a7113ed788 
1/*
2 * Copyright 2013 Google Inc.
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8#ifndef SkMutex_pthread_DEFINED
9#define SkMutex_pthread_DEFINED
10
11/** Posix pthread_mutex based mutex. */
12
13#ifdef SK_DEBUG_PTHREAD_MUTEX
14#include "SkTypes.h"
15#define SkDEBUGCODE_PTHREAD_MUTEX(code) code
16#else
17#define SkDEBUGCODE_PTHREAD_MUTEX(code)
18#ifndef SkDebugf
19    void SkDebugf(const char format[], ...);
20#endif
21#endif
22
23#include <errno.h>
24#include <pthread.h>
25
26// A SkBaseMutex is a POD structure that can be directly initialized
27// at declaration time with SK_DECLARE_STATIC/GLOBAL_MUTEX. This avoids the
28// generation of a static initializer in the final machine code (and
29// a corresponding static finalizer).
30struct SkBaseMutex {
31    void acquire() { pthread_mutex_lock(&fMutex); }
32    void release() { pthread_mutex_unlock(&fMutex); }
33    pthread_mutex_t fMutex;
34};
35
36// A normal mutex that requires to be initialized through normal C++ construction,
37// i.e. when it's a member of another class, or allocated on the heap.
38class SkMutex : public SkBaseMutex {
39public:
40    SkMutex() {
41        SkDEBUGCODE_PTHREAD_MUTEX(int status = )pthread_mutex_init(&fMutex, NULL);
42        SkDEBUGCODE_PTHREAD_MUTEX(
43            if (status != 0) {
44                print_pthread_error(status);
45                SkASSERT(0 == status);
46            }
47        )
48    }
49
50    ~SkMutex() {
51        SkDEBUGCODE_PTHREAD_MUTEX(int status = )pthread_mutex_destroy(&fMutex);
52        SkDEBUGCODE_PTHREAD_MUTEX(
53            if (status != 0) {
54                print_pthread_error(status);
55                SkASSERT(0 == status);
56            }
57        )
58    }
59
60private:
61    SkMutex(const SkMutex&);
62    SkMutex& operator=(const SkMutex&);
63
64    static void print_pthread_error(int status) {
65        switch (status) {
66        case 0: // success
67            break;
68        case EINVAL:
69            SkDebugf("pthread error [%d] EINVAL\n", status);
70            break;
71        case EBUSY:
72            SkDebugf("pthread error [%d] EBUSY\n", status);
73            break;
74        default:
75            SkDebugf("pthread error [%d] unknown\n", status);
76            break;
77        }
78    }
79};
80
81// Using POD-style initialization prevents the generation of a static initializer.
82#define SK_DECLARE_STATIC_MUTEX(name) static SkBaseMutex name = { PTHREAD_MUTEX_INITIALIZER }
83
84// Special case used when the static mutex must be available globally.
85#define SK_DECLARE_GLOBAL_MUTEX(name) SkBaseMutex name = { PTHREAD_MUTEX_INITIALIZER }
86
87#endif
88