safe_binary_mutex.h | Explore in Territory

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/*  safe_binary_mutex.h                                                   */
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#ifndef SAFE_BINARY_MUTEX_H
#define SAFE_BINARY_MUTEX_H

#include "core/error/error_macros.h"
#include "core/os/mutex.h"
#include "core/typedefs.h"

#ifdef THREADS_ENABLED

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wundefined-var-template"
#endif

// A very special kind of mutex, used in scenarios where these
// requirements hold at the same time:
// - Must be used with a condition variable (only binary mutexes are suitable).
// - Must have recursive semnantics (or simulate, as this one does).
// The implementation keeps the lock count in TS. Therefore, only
// one object of each version of the template can exists; hence the Tag argument.
// Tags must be unique across the Godot codebase.
// Also, don't forget to declare the thread_local variable on each use.
template <int Tag>
class SafeBinaryMutex { … };

MutexLock<SafeBinaryMutex<Tag>>;

#ifdef __clang__
#pragma clang diagnostic pop
#endif

#else // No threads.

template <int Tag>
class SafeBinaryMutex {
	struct TLSData {
		TLSData(SafeBinaryMutex<Tag> &p_mutex) {}
	};
	static thread_local TLSData tls_data;

public:
	void lock() const {}
	void unlock() const {}
};

template <int Tag>
class MutexLock<SafeBinaryMutex<Tag>> {
public:
	MutexLock(const SafeBinaryMutex<Tag> &p_mutex) {}
	~MutexLock() {}

	void temp_relock() const {}
	void temp_unlock() const {}
};

#endif // THREADS_ENABLED

#endif // SAFE_BINARY_MUTEX_H
godot/core/os/safe_binary_mutex.h
