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#       1                 :            : // Copyright (c) 2009-2010 Satoshi Nakamoto
#       2                 :            : // Copyright (c) 2009-2020 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_THREADSAFETY_H
#       7                 :            : #define BITCOIN_THREADSAFETY_H
#       8                 :            : 
#       9                 :            : #include <mutex>
#      10                 :            : 
#      11                 :            : #ifdef __clang__
#      12                 :            : // TL;DR Add GUARDED_BY(mutex) to member variables. The others are
#      13                 :            : // rarely necessary. Ex: int nFoo GUARDED_BY(cs_foo);
#      14                 :            : //
#      15                 :            : // See https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
#      16                 :            : // for documentation.  The clang compiler can do advanced static analysis
#      17                 :            : // of locking when given the -Wthread-safety option.
#      18                 :            : #define LOCKABLE __attribute__((lockable))
#      19                 :            : #define SCOPED_LOCKABLE __attribute__((scoped_lockable))
#      20                 :            : #define GUARDED_BY(x) __attribute__((guarded_by(x)))
#      21                 :            : #define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x)))
#      22                 :            : #define ACQUIRED_AFTER(...) __attribute__((acquired_after(__VA_ARGS__)))
#      23                 :            : #define ACQUIRED_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__)))
#      24                 :            : #define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__)))
#      25                 :            : #define SHARED_LOCK_FUNCTION(...) __attribute__((shared_lock_function(__VA_ARGS__)))
#      26                 :            : #define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((exclusive_trylock_function(__VA_ARGS__)))
#      27                 :            : #define SHARED_TRYLOCK_FUNCTION(...) __attribute__((shared_trylock_function(__VA_ARGS__)))
#      28                 :            : #define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__)))
#      29                 :            : #define LOCK_RETURNED(x) __attribute__((lock_returned(x)))
#      30                 :            : #define LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
#      31                 :            : #define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__)))
#      32                 :            : #define SHARED_LOCKS_REQUIRED(...) __attribute__((shared_locks_required(__VA_ARGS__)))
#      33                 :            : #define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
#      34                 :            : #define ASSERT_EXCLUSIVE_LOCK(...) __attribute__((assert_exclusive_lock(__VA_ARGS__)))
#      35                 :            : #else
#      36                 :            : #define LOCKABLE
#      37                 :            : #define SCOPED_LOCKABLE
#      38                 :            : #define GUARDED_BY(x)
#      39                 :            : #define PT_GUARDED_BY(x)
#      40                 :            : #define ACQUIRED_AFTER(...)
#      41                 :            : #define ACQUIRED_BEFORE(...)
#      42                 :            : #define EXCLUSIVE_LOCK_FUNCTION(...)
#      43                 :            : #define SHARED_LOCK_FUNCTION(...)
#      44                 :            : #define EXCLUSIVE_TRYLOCK_FUNCTION(...)
#      45                 :            : #define SHARED_TRYLOCK_FUNCTION(...)
#      46                 :            : #define UNLOCK_FUNCTION(...)
#      47                 :            : #define LOCK_RETURNED(x)
#      48                 :            : #define LOCKS_EXCLUDED(...)
#      49                 :            : #define EXCLUSIVE_LOCKS_REQUIRED(...)
#      50                 :            : #define SHARED_LOCKS_REQUIRED(...)
#      51                 :            : #define NO_THREAD_SAFETY_ANALYSIS
#      52                 :            : #define ASSERT_EXCLUSIVE_LOCK(...)
#      53                 :            : #endif // __GNUC__
#      54                 :            : 
#      55                 :            : // StdMutex provides an annotated version of std::mutex for us,
#      56                 :            : // and should only be used when sync.h Mutex/LOCK/etc are not usable.
#      57                 :            : class LOCKABLE StdMutex : public std::mutex
#      58                 :            : {
#      59                 :            : public:
#      60                 :            : #ifdef __clang__
#      61                 :            :     //! For negative capabilities in the Clang Thread Safety Analysis.
#      62                 :            :     //! A negative requirement uses the EXCLUSIVE_LOCKS_REQUIRED attribute, in conjunction
#      63                 :            :     //! with the ! operator, to indicate that a mutex should not be held.
#      64                 :          0 :     const StdMutex& operator!() const { return *this; }
#      65                 :            : #endif // __clang__
#      66                 :            : };
#      67                 :            : 
#      68                 :            : // StdLockGuard provides an annotated version of std::lock_guard for us,
#      69                 :            : // and should only be used when sync.h Mutex/LOCK/etc are not usable.
#      70                 :            : class SCOPED_LOCKABLE StdLockGuard : public std::lock_guard<StdMutex>
#      71                 :            : {
#      72                 :            : public:
#      73                 :    8338884 :     explicit StdLockGuard(StdMutex& cs) EXCLUSIVE_LOCK_FUNCTION(cs) : std::lock_guard<StdMutex>(cs) {}
#      74                 :    8339193 :     ~StdLockGuard() UNLOCK_FUNCTION() {}
#      75                 :            : };
#      76                 :            : 
#      77                 :            : #endif // BITCOIN_THREADSAFETY_H