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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 "SkNoncopyable.h"
     12 #include "SkRefCnt.h"
     13 #include "SkTArray.h"
     14 
     15 /**
     16  * A simple non-atomic ref used in the GrBackendApi when we don't want to pay for the overhead of a
     17  * threadsafe ref counted object
     18  */
     19 template<typename TSubclass> class GrNonAtomicRef : public SkNoncopyable {
     20 public:
     21     GrNonAtomicRef() : fRefCnt(1) {}
     22 
     23 #ifdef SK_DEBUG
     24     ~GrNonAtomicRef() {
     25         // fRefCnt can be one when a subclass is created statically
     26         SkASSERT((0 == fRefCnt || 1 == fRefCnt));
     27         // Set to invalid values.
     28         fRefCnt = -10;
     29     }
     30 #endif
     31 
     32     bool unique() const { return 1 == fRefCnt; }
     33 
     34     void ref() const {
     35         // Once the ref cnt reaches zero it should never be ref'ed again.
     36         SkASSERT(fRefCnt > 0);
     37         ++fRefCnt;
     38     }
     39 
     40     void unref() const {
     41         SkASSERT(fRefCnt > 0);
     42         --fRefCnt;
     43         if (0 == fRefCnt) {
     44             GrTDeleteNonAtomicRef(static_cast<const TSubclass*>(this));
     45             return;
     46         }
     47     }
     48 
     49 private:
     50     mutable int32_t fRefCnt;
     51 
     52     typedef SkNoncopyable INHERITED;
     53 };
     54 
     55 template<typename T> inline void GrTDeleteNonAtomicRef(const T* ref) {
     56     delete ref;
     57 }
     58 
     59 #endif
     60