1/*
2 * Copyright 2015 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 GrNonAtomicRef_DEFINED
9#define GrNonAtomicRef_DEFINED
10
11#include "SkRefCnt.h"
12#include "SkTArray.h"
13
14/**
15 * A simple non-atomic ref used in the GrBackend when we don't want to pay for the overhead of a
16 * threadsafe ref counted object
17 */
18template<typename TSubclass> class GrNonAtomicRef : public SkNoncopyable {
19public:
20    GrNonAtomicRef() : fRefCnt(1) {}
21
22#ifdef SK_DEBUG
23    ~GrNonAtomicRef() {
24        // fRefCnt can be one when a subclass is created statically
25        SkASSERT((0 == fRefCnt || 1 == fRefCnt));
26        // Set to invalid values.
27        fRefCnt = -10;
28    }
29#endif
30
31    bool unique() const { return 1 == fRefCnt; }
32
33    void ref() const {
34        // Once the ref cnt reaches zero it should never be ref'ed again.
35        SkASSERT(fRefCnt > 0);
36        ++fRefCnt;
37    }
38
39    void unref() const {
40        SkASSERT(fRefCnt > 0);
41        --fRefCnt;
42        if (0 == fRefCnt) {
43            GrTDeleteNonAtomicRef(static_cast<const TSubclass*>(this));
44            return;
45        }
46    }
47
48private:
49    mutable int32_t fRefCnt;
50
51    typedef SkNoncopyable INHERITED;
52};
53
54template<typename T> inline void GrTDeleteNonAtomicRef(const T* ref) {
55    delete ref;
56}
57
58#endif
59