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- #pragma once
- #include "../C/Baselib_Lock.h"
- #include "Time.h"
- namespace baselib
- {
- BASELIB_CPP_INTERFACE
- {
- // In computer science, a lock or mutex (from mutual exclusion) is a synchronization mechanism for enforcing limits on access to a resource in an environment
- // where there are many threads of execution. A lock is designed to enforce a mutual exclusion concurrency control policy.
- //
- // "Lock (computer science)", Wikipedia: The Free Encyclopedia
- // https://en.wikipedia.org/w/index.php?title=Lock_(computer_science)&oldid=875674239
- class Lock
- {
- public:
- // non-copyable
- Lock(const Lock& other) = delete;
- Lock& operator=(const Lock& other) = delete;
- // non-movable (strictly speaking not needed but listed to signal intent)
- Lock(Lock&& other) = delete;
- Lock& operator=(Lock&& other) = delete;
- // Creates a lock synchronization primitive.
- // If there are not enough system resources to create a lock, process abort is triggered.
- Lock()
- {
- Baselib_Lock_CreateInplace(&m_LockData);
- }
- // Reclaim resources and memory held by lock.
- // If threads are waiting on the lock, calling free may trigger an assert and may cause process abort.
- ~Lock()
- {
- Baselib_Lock_FreeInplace(&m_LockData);
- }
- // Acquire lock.
- //
- // If lock is held, either by this or another thread, then the function wait for lock to be released.
- //
- // This function is guaranteed to emit an acquire barrier.
- inline void Acquire()
- {
- return Baselib_Lock_Acquire(&m_LockData);
- }
- // Try to acquire lock and return immediately.
- // If lock is held, either by this or another thread, then lock is not acquired and function return false.
- //
- // When a lock is acquired this function is guaranteed to emit an acquire barrier.
- //
- // Return: true if lock was acquired.
- COMPILER_WARN_UNUSED_RESULT
- FORCE_INLINE bool TryAcquire()
- {
- return Baselib_Lock_TryAcquire(&m_LockData);
- }
- // Try to acquire lock.
- // If lock is held, either by this or another thread, then the function wait for timeoutInMilliseconds for lock to be released.
- //
- // When a lock is acquired this function is guaranteed to emit an acquire barrier.
- //
- // TryAcquire with a zero timeout differs from TryAcquire() in that TryAcquire() is guaranteed to be a user space operation
- // while TryAcquire with zero timeout may enter the kernel and cause a context switch.
- //
- // Timeout passed to this function may be subject to system clock resolution.
- // If the system clock has a resolution of e.g. 16ms that means this function may exit with a timeout error 16ms earlier than originally scheduled.
- //
- // Return: true if lock was acquired.
- COMPILER_WARN_UNUSED_RESULT
- FORCE_INLINE bool TryTimedAcquire(const timeout_ms timeoutInMilliseconds)
- {
- return Baselib_Lock_TryTimedAcquire(&m_LockData, timeoutInMilliseconds.count());
- }
- // Release lock and make it available to other threads.
- //
- // This function can be called from any thread, not only the thread that acquired the lock.
- // If no lock was previously held calling this function result in a no-op.
- //
- // When the lock is released this function is guaranteed to emit a release barrier.
- FORCE_INLINE void Release()
- {
- return Baselib_Lock_Release(&m_LockData);
- }
- // Acquire lock and invoke user defined function.
- // If lock is held, either by this or another thread, then the function wait for lock to be released.
- //
- // When a lock is acquired this function is guaranteed to emit an acquire barrier.
- //
- // Example usage:
- // lock.AcquireScoped([] {
- // enteredCriticalSection++;
- // });
- template<class FunctionType>
- FORCE_INLINE void AcquireScoped(const FunctionType& func)
- {
- ReleaseOnDestroy releaseScope(*this);
- Acquire();
- func();
- }
- // Try to acquire lock and invoke user defined function.
- // If lock is held, either by this or another thread, then lock is not acquired and function return false.
- // On failure to obtain lock the user defined function is not invoked.
- //
- // When a lock is acquired this function is guaranteed to emit an acquire barrier.
- //
- // Example usage:
- // lock.TryAcquireScoped([] {
- // enteredCriticalSection++;
- // });
- //
- // Return: true if lock was acquired.
- template<class FunctionType>
- FORCE_INLINE bool TryAcquireScoped(const FunctionType& func)
- {
- if (TryAcquire())
- {
- ReleaseOnDestroy releaseScope(*this);
- func();
- return true;
- }
- return false;
- }
- // Try to acquire lock and invoke user defined function.
- // If lock is held, either by this or another thread, then the function wait for timeoutInMilliseconds for lock to be released.
- // On failure to obtain lock the user defined function is not invoked.
- //
- // When a lock is acquired this function is guaranteed to emit an acquire barrier.
- //
- // Timeout passed to this function may be subject to system clock resolution.
- // If the system clock has a resolution of e.g. 16ms that means this function may exit with a timeout error 16ms earlier than originally scheduled.
- //
- // Example usage:
- // bool lockAcquired = lock.TryTimedAcquireScoped(std::chrono::minutes(1), [] {
- // enteredCriticalSection++;
- // });
- // assert(lockAcquired);
- //
- // Return: true if lock was acquired.
- template<class FunctionType>
- FORCE_INLINE bool TryTimedAcquireScoped(const timeout_ms timeoutInMilliseconds, const FunctionType& func)
- {
- if (TryTimedAcquire(timeoutInMilliseconds))
- {
- ReleaseOnDestroy releaseScope(*this);
- func();
- return true;
- }
- return false;
- }
- private:
- class ReleaseOnDestroy
- {
- public:
- FORCE_INLINE ReleaseOnDestroy(Lock& lockReference) : m_LockReference(lockReference) {}
- FORCE_INLINE ~ReleaseOnDestroy() { m_LockReference.Release(); }
- private:
- Lock& m_LockReference;
- };
- Baselib_Lock m_LockData;
- };
- }
- }
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