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  */
18 template<typename TSubclass> class GrNonAtomicRef : public SkNoncopyable {
19 public:
GrNonAtomicRef()20     GrNonAtomicRef() : fRefCnt(1) {}
21 
22 #ifdef SK_DEBUG
~GrNonAtomicRef()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 
unique()31     bool unique() const { return 1 == fRefCnt; }
32 
ref()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 
unref()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 
48 private:
49     mutable int32_t fRefCnt;
50 
51     typedef SkNoncopyable INHERITED;
52 };
53 
GrTDeleteNonAtomicRef(const T * ref)54 template<typename T> inline void GrTDeleteNonAtomicRef(const T* ref) {
55     delete ref;
56 }
57 
58 #endif
59