stdmutex.h raw

   1  // Copyright (c) 2009-2010 Satoshi Nakamoto
   2  // Copyright (c) 2009-present The Bitcoin Core developers
   3  // Distributed under the MIT software license, see the accompanying
   4  // file COPYING or http://www.opensource.org/licenses/mit-license.php.
   5  
   6  #ifndef BITCOIN_UTIL_STDMUTEX_H
   7  #define BITCOIN_UTIL_STDMUTEX_H
   8  
   9  // This header declares threading primitives compatible with Clang
  10  // Thread Safety Analysis and provides appropriate annotation macros.
  11  #include <threadsafety.h> // IWYU pragma: export
  12  
  13  #include <util/macros.h>
  14  
  15  #include <mutex>
  16  
  17  // StdMutex provides an annotated version of std::mutex for us,
  18  // and should only be used when sync.h Mutex/LOCK/etc are not usable.
  19  class LOCKABLE StdMutex : public std::mutex
  20  {
  21  public:
  22  #ifdef __clang__
  23      //! For negative capabilities in the Clang Thread Safety Analysis.
  24      //! A negative requirement uses the EXCLUSIVE_LOCKS_REQUIRED attribute, in conjunction
  25      //! with the ! operator, to indicate that a mutex should not be held.
  26      const StdMutex& operator!() const { return *this; }
  27  #endif // __clang__
  28  
  29      // StdMutex::Guard provides an annotated version of std::lock_guard for us.
  30      class SCOPED_LOCKABLE Guard : public std::lock_guard<StdMutex>
  31      {
  32      public:
  33          explicit Guard(StdMutex& cs) EXCLUSIVE_LOCK_FUNCTION(cs) : std::lock_guard<StdMutex>(cs) {}
  34          ~Guard() UNLOCK_FUNCTION() = default;
  35      };
  36  
  37      static inline StdMutex& CheckNotHeld(StdMutex& cs) EXCLUSIVE_LOCKS_REQUIRED(!cs) LOCK_RETURNED(cs) { return cs; }
  38  };
  39  
  40  // Provide STDLOCK(..) wrapper around StdMutex::Guard that checks the lock is not already held
  41  #define STDLOCK(cs) StdMutex::Guard BITCOIN_UNIQUE_NAME(criticalblock){StdMutex::CheckNotHeld(cs)}
  42  
  43  #endif // BITCOIN_UTIL_STDMUTEX_H
  44