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      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:
     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 
     48 private:
     49     mutable int32_t fRefCnt;
     50 
     51     typedef SkNoncopyable INHERITED;
     52 };
     53 
     54 template<typename T> inline void GrTDeleteNonAtomicRef(const T* ref) {
     55     delete ref;
     56 }
     57 
     58 #endif
     59