vlc_atomic.h File Reference

Atomic operations do not require locking, but they are not very powerful. More...

Include dependency graph for vlc_atomic.h:

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Data Structures
struct	vlc_atomic_rc_t

Macros
#define	VLC_STATIC_RC

Typedefs
typedef struct vlc_atomic_rc_t	vlc_atomic_rc_t

Functions
static void	vlc_atomic_rc_init (vlc_atomic_rc_t *rc)
	Init the RC to 1. More...
static void	vlc_atomic_rc_inc (vlc_atomic_rc_t *rc)
	Increment the RC. More...
static bool	vlc_atomic_rc_dec (vlc_atomic_rc_t *rc)
	Decrement the RC and return true if it reaches 0. More...
static uintptr_t	vlc_atomic_rc_get (const vlc_atomic_rc_t *rc)
	Returns the current reference count. More...
void	vlc_atomic_wait (void *addr, unsigned val)
	Waits on an address. More...
int	vlc_atomic_timedwait (void *addr, unsigned val, vlc_tick_t deadline)
	Waits on an address with a time-out. More...
int	vlc_atomic_timedwait_daytime (void *addr, unsigned val, time_t deadline)
void	vlc_atomic_notify_one (void *addr)
	Wakes up one thread on an address. More...
void	vlc_atomic_notify_all (void *addr)
	Wakes up all thread on an address. More...

Detailed Description

Atomic operations do not require locking, but they are not very powerful.

Macro Definition Documentation

VLC_STATIC_RC

#define VLC_STATIC_RC

Value:

    { \
    .refs = ATOMIC_VAR_INIT(0) \
}

Typedef Documentation

vlc_atomic_rc_t

typedef struct vlc_atomic_rc_t vlc_atomic_rc_t

Function Documentation

vlc_atomic_notify_all()

void vlc_atomic_notify_all

(

void *

addr

)

Wakes up all thread on an address.

Wakes up all threads sleeping on the specified address (if any). Any thread sleeping within a call to vlc_atomic_wait() or vlc_atomic_timedwait() with the specified address as first call parameter will be woken up.

Parameters

addr	address identifying which threads to wake up

References wait_bucket::lock, vlc_futex_wake(), vlc_umtx_wake(), wait_bucket::wait, wait_bucket_get(), and wait_bucket::waiters.

Referenced by vlc_atomic_notify_one(), vlc_latch_count_down_ready(), vlc_once_complete(), and vlc_queuedmutex_unlock().

vlc_atomic_notify_one()

void vlc_atomic_notify_one

(

void *

addr

)

Wakes up one thread on an address.

Wakes up (at least) one of the thread sleeping on the specified address. The address must be equal to the first parameter given by at least one thread sleeping within the vlc_atomic_wait() or vlc_atomic_timedwait() functions. If no threads are found, this function does nothing.

Parameters

addr	address identifying which threads may be woken up

References vlc_atomic_notify_all(), vlc_futex_wake(), and vlc_umtx_wake().

Referenced by vlc_cancel(), vlc_cond_signal_waiter(), vlc_mutex_unlock(), vlc_rcu_read_unlock(), and vlc_sem_post().

vlc_atomic_rc_dec()

static bool vlc_atomic_rc_dec ( vlc_atomic_rc_t *  rc )

inlinestatic

Decrement the RC and return true if it reaches 0.

References vlc_atomic_rc_t::refs, and vlc_assert.

Referenced by addon_entry_Release(), aout_Release(), EsRelease(), input_item_Release(), input_resource_Release(), input_source_Release(), picture_pool_Destroy(), picture_Release(), TaskRelease(), vlc_ancillary_Release(), vlc_decoder_device_Release(), vlc_input_attachment_Release(), vlc_media_source_Release(), vlc_media_tree_Release(), vlc_player_title_list_Release(), vlc_playlist_item_Release(), vlc_renderer_item_release(), vlc_thumbnailer_DestroyRequest(), vlc_video_context_Release(), and vout_Release().

vlc_atomic_rc_get()

static uintptr_t vlc_atomic_rc_get ( const vlc_atomic_rc_t *  rc )

inlinestatic

Returns the current reference count.

This is not safe to use for logic and must only be used for debugging or assertion purposes

References vlc_atomic_rc_t::refs.

Referenced by picture_Destroy(), picture_pool_Get(), and picture_pool_Wait().

vlc_atomic_rc_inc()

static void vlc_atomic_rc_inc ( vlc_atomic_rc_t *  rc )

inlinestatic

Increment the RC.

References vlc_atomic_rc_t::refs, vlc_assert, and VLC_UNUSED.

Referenced by addon_entry_Hold(), aout_Hold(), EsHold(), input_item_Hold(), input_resource_Hold(), input_source_Hold(), picture_Hold(), picture_pool_ClonePicture(), RequestCommon(), vlc_ancillary_Hold(), vlc_decoder_device_Hold(), vlc_input_attachment_Hold(), vlc_media_source_Hold(), vlc_media_tree_Hold(), vlc_player_title_list_Hold(), vlc_playlist_item_Hold(), vlc_renderer_item_hold(), vlc_video_context_Hold(), and vout_Hold().

vlc_atomic_rc_init()

static void vlc_atomic_rc_init ( vlc_atomic_rc_t *  rc )

inlinestatic

Init the RC to 1.

References vlc_atomic_rc_t::refs.

Referenced by addon_entry_New(), aout_New(), EsOutAddLocked(), input_item_NewExt(), input_resource_New(), InputSourceNew(), picture_InitPrivate(), picture_pool_New(), TaskNew(), vlc_ancillary_CreateWithFreeCb(), vlc_decoder_device_Create(), vlc_input_attachment_New(), vlc_media_source_New(), vlc_media_tree_New(), vlc_player_title_list_Create(), vlc_playlist_item_New(), vlc_renderer_item_new(), vlc_video_context_Create(), and vout_CreateCommon().

vlc_atomic_timedwait()

int vlc_atomic_timedwait	(	void *	addr,
		unsigned	val,
		vlc_tick_t	deadline
	)

Waits on an address with a time-out.

This function operates as vlc_atomic_wait() but provides an additional time-out. If the deadline is reached, the thread resumes and the function returns.

Parameters

addr	address to check for
val	value to match at the address
deadline	deadline to wait until

Return values

0	the function was woken up before the time-out
ETIMEDOUT	the deadline was reached

References count, wait_bucket::lock, MS_FROM_VLC_TICK, unlikely, vlc_assert_unreachable, vlc_atomic_timedwait_timespec(), vlc_cleanup_pop, vlc_cleanup_push, vlc_futex_wait(), vlc_testcancel(), VLC_TICK_FROM_MS, vlc_tick_now(), vlc_tick_to_timespec(), vlc_timespec_adjust(), vlc_umtx_wait(), vlc_WaitForSingleObject(), wait_bucket::wait, wait_bucket_enter(), and wait_bucket_leave().

Referenced by vlc_cond_timedwait(), vlc_sem_timedwait(), and vlc_tick_wait().

vlc_atomic_timedwait_daytime()

int vlc_atomic_timedwait_daytime	(	void *	addr,
		unsigned	val,
		time_t	deadline
	)

References count, wait_bucket::lock, timespec::tv_sec, unlikely, vlc_assert_unreachable, vlc_atomic_timedwait_timespec(), vlc_cleanup_pop, vlc_cleanup_push, vlc_futex_wait(), vlc_testcancel(), vlc_timespec_adjust(), vlc_WaitForSingleObject(), wait_bucket::wait, wait_bucket_enter(), and wait_bucket_leave().

Referenced by vlc_cond_timedwait_daytime().

vlc_atomic_wait()

void vlc_atomic_wait	(	void *	addr,
		unsigned	val
	)

Waits on an address.

Puts the calling thread to sleep if a specific unsigned 32-bits value is stored at a specified address. The thread will sleep until it is woken up by a call to vlc_atomic_notify_one() or vlc_atomic_notify_all() in another thread, or spuriously.

If the value does not match, do nothing and return immediately.

Parameters

addr	address to check for
val	value to match at the address

References count, wait_bucket::lock, vlc_cleanup_pop, vlc_cleanup_push, vlc_futex_wait(), vlc_testcancel(), vlc_umtx_wait(), vlc_WaitForSingleObject(), wait_bucket::wait, wait_bucket_enter(), and wait_bucket_leave().

Referenced by vlc_cond_wait(), vlc_latch_wait(), vlc_mutex_lock(), vlc_once_begin(), vlc_queuedmutex_lock(), vlc_rcu_synchronize(), and vlc_sem_wait().