/[svn]/linuxsampler/trunk/src/common/Ref.h
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Diff of /linuxsampler/trunk/src/common/Ref.h

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revision 3768 by schoenebeck, Fri May 15 19:52:31 2020 UTC revision 3769 by schoenebeck, Fri May 15 20:16:39 2020 UTC
# Line 41  Line 41 
41  # define LS_REF_ATOMIC 1  # define LS_REF_ATOMIC 1
42  #endif  #endif
43    
44  //NOTE: We are using our own atomic implementation instead of std::atomic of the  //NOTE: We are using our own atomic implementation for atomic increment and
45  // C++ STL, because our atomic implementation is lock-free and wait-free. The  // decrement instead of std::atomic of the C++ STL, because our atomic
46  // C++ standard just recommends, but does not guarantee lock-free implementation  // implementation is lock-free and wait-free. The C++ standard just recommends,
47  // (state of the C++20 standard as of 2020-04-27):  // but does not guarantee lock-free implementation (state of the C++20 standard
48    // as of 2020-04-27):
49  // https://en.cppreference.com/w/cpp/atomic/atomic/is_lock_free  // https://en.cppreference.com/w/cpp/atomic/atomic/is_lock_free
50    // For CAS though we simply use the STL version, since it is only used on
51    // resource deallocation, which is not real-time safe anyway.
52  #if LS_REF_ATOMIC  #if LS_REF_ATOMIC
53  # include "atomic.h"  # include "atomic.h"
54  # include <stdatomic.h>  # include <atomic>
 # if __STDC_NO_ATOMICS__  
 #  undef LS_REF_ATOMIC  
 #  warning Ref<> class will not be thread safe, since compiler does not support C11 atomics!  
 # endif  
55  #else  #else
56  # warning Ref<> class will not be thread safe (feature explicitly disabled)!  # warning Ref<> class will not be thread safe (feature explicitly disabled)!
57  #endif  #endif
# Line 93  namespace LinuxSampler { Line 92  namespace LinuxSampler {
92                  ptr(p)                  ptr(p)
93              {              {
94                  #if LS_REF_ATOMIC                  #if LS_REF_ATOMIC
95                  atomic_store(&zombi, released);                  std::atomic_store(&zombi, released);
96                  #endif                  #endif
97                  #if LS_REF_VERBOSE_DEBUG_MSG                  #if LS_REF_VERBOSE_DEBUG_MSG
98                  printf("Ref %p: new counter (refs=%d)\n", ptr,                  printf("Ref %p: new counter (refs=%d)\n", ptr,
# Line 156  namespace LinuxSampler { Line 155  namespace LinuxSampler {
155                  # endif                  # endif
156                  if (!zero) return;                  if (!zero) return;
157                  bool expect = false;                  bool expect = false;
158                  bool release = atomic_compare_exchange_strong(&zombi, &expect, true);                  bool release = std::atomic_compare_exchange_strong(&zombi, &expect, true);
159                  if (release) deletePtr();                  if (release) deletePtr();
160                  #else                  #else
161                  if (!references) return;                  if (!references) return;
# Line 197  namespace LinuxSampler { Line 196  namespace LinuxSampler {
196    
197              #if LS_REF_ATOMIC              #if LS_REF_ATOMIC
198              atomic_t references;              atomic_t references;
199              atomic_bool zombi; ///< @c false if not released yet, @c true once @c ptr was released              std::atomic<bool> zombi; ///< @c false if not released yet, @c true once @c ptr was released
200              #else              #else
201              int references;              int references;
202              #endif              #endif
# Line 299  namespace LinuxSampler { Line 298  namespace LinuxSampler {
298      public:      public:
299          typedef RefBase<T_BASE> RefBaseT;          typedef RefBase<T_BASE> RefBaseT;
300          typedef typename RefBase<T_BASE>::RefCounter RefCounter;          typedef typename RefBase<T_BASE>::RefCounter RefCounter;
301            
302          Ref() : RefBaseT() {          Ref() : RefBaseT() {
303              #if LS_REF_VERBOSE_DEBUG_MSG              #if LS_REF_VERBOSE_DEBUG_MSG
304              printf("Ref empty ctor Ref:%p\n", this);              printf("Ref empty ctor Ref:%p\n", this);
# Line 379  namespace LinuxSampler { Line 378  namespace LinuxSampler {
378          inline operator RefBaseT&() {          inline operator RefBaseT&() {
379              return *this;              return *this;
380          }          }
381            
382          inline operator const RefBaseT&() const {          inline operator const RefBaseT&() const {
383              return *this;              return *this;
384          }          }
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