Lock.h

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/*
 * Copyright (C) 1996-2023 The Squid Software Foundation and contributors
 *
 * Squid software is distributed under GPLv2+ license and includes
 * contributions from numerous individuals and organizations.
 * Please see the COPYING and CONTRIBUTORS files for details.
 */
 
#ifndef SQUID_SRC_BASE_LOCK_H
#define SQUID_SRC_BASE_LOCK_H
 
class Lock
{
public:
    Lock():count_(0) {}
 
    virtual ~Lock() { assert(count_ == 0); }
 
    void lock() const {
#if defined(LOCKCOUNT_DEBUG)
        debugs(0,1, "Incrementing this " << static_cast<void*>(this) << " from count " << count_);
#endif
        assert(count_ < UINT32_MAX);
        ++count_;
    }
 
    uint32_t unlock() const {
#if defined(LOCKCOUNT_DEBUG)
        debugs(0,1, "Decrementing this " << static_cast<void*>(this) << " from count " << count_);
#endif
        assert(count_ > 0);
        return --count_;
    }
 
    uint32_t LockCount() const { return count_; }
 
private:
    mutable uint32_t count_; 
};
 
// For clarity we provide some aliases for the tracking mechanisms
// using Lock so that we can easily see what type of smart pointers
// are to be used for the child object.
// NP: CbcPointer<> and RefCount<> pointers should be used consistently
//     for any given child class type
 
#define RefCountable virtual Lock
 
#endif /* SQUID_SRC_BASE_LOCK_H */