56 lines
1.2 KiB
C++
56 lines
1.2 KiB
C++
#ifndef MEMGRAPH_THREADING_SYNC_TIMED_SPINLOCK_HPP
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#define MEMGRAPH_THREADING_SYNC_TIMED_SPINLOCK_HPP
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#include <atomic>
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#include <chrono>
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#include <stdexcept>
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#include <unistd.h>
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class LockExpiredError : public std::runtime_error
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{
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using runtime_error::runtime_error;
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};
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class TimedSpinLock
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{
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public:
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TimedSpinLock(std::chrono::seconds expiration)
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: expiration(expiration) {}
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TimedSpinLock(std::chrono::milliseconds expiration)
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: expiration(expiration) {}
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void lock()
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{
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using clock = std::chrono::high_resolution_clock;
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auto start = clock::now();
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while(lock_flag.test_and_set(std::memory_order_acquire))
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{
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// how long have we been locked? if we exceeded the expiration
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// time, throw an exception and stop being blocked because this
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// might be a deadlock!
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if(clock::now() - start > expiration)
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throw LockExpiredError("This lock has expired");
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usleep(250);
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}
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}
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void unlock()
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{
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lock_flag.clear(std::memory_order_release);
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}
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private:
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std::chrono::milliseconds expiration;
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// guaranteed by standard to be lock free!
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std::atomic_flag lock_flag = ATOMIC_FLAG_INIT;
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};
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#endif
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