NOTE: This class is not thread-safe. More...

#include <reader_writer_lock.hpp>

Collaboration diagram for m::detail::reader_writer_mutex_internal:

Public Member Functions
uint16_t	readers_waiting () const

uint16_t	readers_active () const

uint16_t	writers_waiting () const

bool	writer_active () const

bool	reader_wants_upgrade () const

void	request_read_lock ()
	Inform others that we want to acquire a read lock.

void	request_write_lock ()
	Inform others that we want to acquire the write lock.

bool	try_request_upgrade ()
	Try to request an upgrade.

bool	can_acquire_read_lock () const
	The mutex is in a state where a reader can acquire a reader (shared) lock.

bool	can_acquire_write_lock () const
	The mutex is in a state where a writer can acquire a write (exclusive) lock.

bool	can_upgrade_lock () const
	The mutex is in a state where a reader can claim the write (exclusive) lock.

void	acquire_read_lock ()
	Acquires a previously requested read lock.

void	acquire_write_lock ()

void	release_read_lock ()
	Releases a previously acquired read lock.

void	release_write_lock ()

void	upgrade_lock ()
	Upgrades an already held read lock to a write lock, after previously requesting to upgrade.

Private Attributes
uint16_t	readers_waiting_ {0}
	The number of readers waiting to acquire a read lock.

uint16_t	writers_waiting_ {0}
	The number of writers waiting to acquire the singular write lock.

uint16_t	readers_active_ {0}
	The number of currently active readers, i.e.

bool	writer_active_ {false}
	As there can be at most one active writer, we track this information with a `bool`.

bool	reader_wants_upgrade_ {false}
	Whether a single reader wants to upgrade to a writer.

Detailed Description

NOTE: This class is not thread-safe.

It is the duty of the user to guard accesses to instances of this class.

Definition at line 18 of file reader_writer_lock.hpp.

Member Function Documentation

◆ acquire_read_lock()

void m::detail::reader_writer_mutex_internal::acquire_read_lock ( )

inline

Acquires a previously requested read lock.

Definition at line 72 of file reader_writer_lock.hpp.

References can_acquire_read_lock(), M_insist, readers_active_, readers_waiting(), and readers_waiting_.

Referenced by m::reader_writer_mutex::lock_read(), and m::reader_writer_mutex::try_lock_read().

◆ acquire_write_lock()

void m::detail::reader_writer_mutex_internal::acquire_write_lock ( )

inline

Definition at line 79 of file reader_writer_lock.hpp.

References can_acquire_write_lock(), M_insist, writer_active_, writers_waiting(), and writers_waiting_.

Referenced by m::reader_writer_mutex::lock_write(), m::reader_writer_mutex::try_lock_write(), and upgrade_lock().

◆ can_acquire_read_lock()

bool m::detail::reader_writer_mutex_internal::can_acquire_read_lock ( ) const

inline

The mutex is in a state where a reader can acquire a reader (shared) lock.

Definition at line 59 of file reader_writer_lock.hpp.

References m::and, reader_wants_upgrade(), writer_active(), and writers_waiting().

Referenced by acquire_read_lock(), m::reader_writer_mutex::lock_read(), and m::reader_writer_mutex::try_lock_read().

◆ can_acquire_write_lock()

bool m::detail::reader_writer_mutex_internal::can_acquire_write_lock ( ) const

inline

The mutex is in a state where a writer can acquire a write (exclusive) lock.

Definition at line 63 of file reader_writer_lock.hpp.

References m::and, readers_active(), and writer_active().

Referenced by acquire_write_lock(), m::reader_writer_mutex::lock_write(), and m::reader_writer_mutex::try_lock_write().

◆ can_upgrade_lock()

bool m::detail::reader_writer_mutex_internal::can_upgrade_lock ( ) const

inline

The mutex is in a state where a reader can claim the write (exclusive) lock.

Definition at line 65 of file reader_writer_lock.hpp.

References m::and, M_insist, reader_wants_upgrade(), readers_active(), writer_active(), and writers_waiting().

Referenced by m::reader_writer_mutex::upgrade(), and upgrade_lock().

◆ reader_wants_upgrade()

bool m::detail::reader_writer_mutex_internal::reader_wants_upgrade ( ) const

inline

Definition at line 38 of file reader_writer_lock.hpp.

References reader_wants_upgrade_.

Referenced by can_acquire_read_lock(), can_upgrade_lock(), try_request_upgrade(), m::reader_writer_mutex::unlock_read(), and m::reader_writer_mutex::upgrade().

◆ readers_active()

uint16_t m::detail::reader_writer_mutex_internal::readers_active ( ) const

inline

Definition at line 35 of file reader_writer_lock.hpp.

References readers_active_.

Referenced by can_acquire_write_lock(), can_upgrade_lock(), release_read_lock(), release_write_lock(), m::reader_writer_mutex::unlock_read(), m::reader_writer_mutex::unlock_write(), and upgrade_lock().

◆ readers_waiting()

uint16_t m::detail::reader_writer_mutex_internal::readers_waiting ( ) const

inline

Definition at line 34 of file reader_writer_lock.hpp.

References readers_waiting_.

Referenced by acquire_read_lock(), and m::reader_writer_mutex::unlock_write().

◆ release_read_lock()

void m::detail::reader_writer_mutex_internal::release_read_lock ( )

inline

Releases a previously acquired read lock.

Definition at line 87 of file reader_writer_lock.hpp.

References M_insist, readers_active(), readers_active_, and writer_active().

Referenced by m::reader_writer_mutex::unlock_read(), and upgrade_lock().

◆ release_write_lock()

void m::detail::reader_writer_mutex_internal::release_write_lock ( )

inline

Definition at line 94 of file reader_writer_lock.hpp.

References M_insist, readers_active(), writer_active(), and writer_active_.

Referenced by m::reader_writer_mutex::unlock_write().

◆ request_read_lock()

void m::detail::reader_writer_mutex_internal::request_read_lock ( )

inline

Inform others that we want to acquire a read lock.

Definition at line 41 of file reader_writer_lock.hpp.

References readers_waiting_.

Referenced by m::reader_writer_mutex::lock_read(), and m::reader_writer_mutex::try_lock_read().

◆ request_write_lock()

void m::detail::reader_writer_mutex_internal::request_write_lock ( )

inline

Inform others that we want to acquire the write lock.

Definition at line 43 of file reader_writer_lock.hpp.

References writers_waiting_.

Referenced by m::reader_writer_mutex::lock_write(), m::reader_writer_mutex::try_lock_write(), and try_request_upgrade().

◆ try_request_upgrade()

bool m::detail::reader_writer_mutex_internal::try_request_upgrade ( )

inline

Try to request an upgrade.

On success, inform others that we want to upgrade our held read lock to the write lock. When request succeeds, upgrading afterwards is guaranteed to terminate eventually.