// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2018 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_THREADSAFETY_H
#define BITCOIN_THREADSAFETY_H

#ifdef __clang__
// TL;DR Add GUARDED_BY(mutex) to member variables. The others are
// rarely necessary. Ex: int nFoo GUARDED_BY(cs_foo);
//
// See https://clang.llvm.org/docs/ThreadSafetyAnalysis.html
// for documentation.  The clang compiler can do advanced static analysis
// of locking when given the -Wthread-safety option.
#define LOCKABLE __attribute__((lockable))
#define SCOPED_LOCKABLE __attribute__((scoped_lockable))
#define GUARDED_BY(x) __attribute__((guarded_by(x)))
#define GUARDED_VAR __attribute__((guarded_var))
#define PT_GUARDED_BY(x) __attribute__((pt_guarded_by(x)))
#define PT_GUARDED_VAR __attribute__((pt_guarded_var))
#define ACQUIRED_AFTER(...) __attribute__((acquired_after(__VA_ARGS__)))
#define ACQUIRED_BEFORE(...) __attribute__((acquired_before(__VA_ARGS__)))
#define EXCLUSIVE_LOCK_FUNCTION(...) __attribute__((exclusive_lock_function(__VA_ARGS__)))
#define SHARED_LOCK_FUNCTION(...) __attribute__((shared_lock_function(__VA_ARGS__)))
#define EXCLUSIVE_TRYLOCK_FUNCTION(...) __attribute__((exclusive_trylock_function(__VA_ARGS__)))
#define SHARED_TRYLOCK_FUNCTION(...) __attribute__((shared_trylock_function(__VA_ARGS__)))
#define UNLOCK_FUNCTION(...) __attribute__((unlock_function(__VA_ARGS__)))
#define LOCK_RETURNED(x) __attribute__((lock_returned(x)))
#define LOCKS_EXCLUDED(...) __attribute__((locks_excluded(__VA_ARGS__)))
#define EXCLUSIVE_LOCKS_REQUIRED(...) __attribute__((exclusive_locks_required(__VA_ARGS__)))
#define SHARED_LOCKS_REQUIRED(...) __attribute__((shared_locks_required(__VA_ARGS__)))
#define NO_THREAD_SAFETY_ANALYSIS __attribute__((no_thread_safety_analysis))
#define ASSERT_EXCLUSIVE_LOCK(...) __attribute((assert_exclusive_lock(__VA_ARGS__)))
#else
#define LOCKABLE
#define SCOPED_LOCKABLE
#define GUARDED_BY(x)
#define GUARDED_VAR
#define PT_GUARDED_BY(x)
#define PT_GUARDED_VAR
#define ACQUIRED_AFTER(...)
#define ACQUIRED_BEFORE(...)
#define EXCLUSIVE_LOCK_FUNCTION(...)
#define SHARED_LOCK_FUNCTION(...)
#define EXCLUSIVE_TRYLOCK_FUNCTION(...)
#define SHARED_TRYLOCK_FUNCTION(...)
#define UNLOCK_FUNCTION(...)
#define LOCK_RETURNED(x)
#define LOCKS_EXCLUDED(...)
#define EXCLUSIVE_LOCKS_REQUIRED(...)
#define SHARED_LOCKS_REQUIRED(...)
#define NO_THREAD_SAFETY_ANALYSIS
#define ASSERT_EXCLUSIVE_LOCK(...)
#endif // __GNUC__

// Utility class for indicating to compiler thread analysis that a mutex is
// locked (when it couldn't be determined otherwise).
struct SCOPED_LOCKABLE LockAnnotation
{
    template <typename Mutex>
    explicit LockAnnotation(Mutex& mutex) EXCLUSIVE_LOCK_FUNCTION(mutex)
    {
    }
    ~LockAnnotation() UNLOCK_FUNCTION() {}
};

#endif // BITCOIN_THREADSAFETY_H
