A generic collection of callbacks for event types represented as a bitmask, intended to be wrapped for each usage. More...

#include <util/u_generic_callbacks.hpp>

Public Types
using	callback_t = CallbackType

using	event_t = EventBitflagType

using	mask_t = detail::mask_from_enum_t< EventBitflagType >

Public Member Functions
void	addCallback (CallbackType callback, mask_t event_mask, void *userdata)
	Add a new callback entry with the given callback function pointer, event mask, and user data. More...

int	removeCallback (CallbackType callback, mask_t event_mask, void *userdata, unsigned int num_skip=0, int max_remove=-1)
	Remove some number of callback entries matching the given callback function pointer, event mask, and user data. More...

bool	contains (CallbackType callback, mask_t event_mask, void *userdata)
	See if the collection contains at least one matching callback. More...

template<typename F >
int	invokeCallbacks (EventBitflagType event, F &&invoker)
	Invokes the callbacks, by passing the ones we should run to your "invoker" to add any desired context/event data and forward the call. More...

Detailed Description

template<typename CallbackType, typename EventBitflagType>
struct xrt::auxiliary::util::GenericCallbacks< CallbackType, EventBitflagType >

A generic collection of callbacks for event types represented as a bitmask, intended to be wrapped for each usage.

A registered callback may identify one or more event types (bits in the bitmask) that it wants to be invoked for. A userdata void pointer is also stored for each callback. Bitmasks are tested at invocation time, and the general callback format allows for callbacks to indicate they should be removed from the collection. Actually calling each callback is left to a consumer-provided "invoker" to allow adding context and event data to the call. The "invoker" also allows the option of whether or how to expose the self-removal capability: yours might simply always return "false".

This generic structure supports callbacks that are included multiple times in the collection, if the consuming code needs it. GenericCallbacks::contains may be used by consuming code before conditionally calling addCallback, to limit to a single instance in a collection.

Template Parameters

CallbackType	the function pointer type to store for each callback.
EventBitflagType	the event enum type.

Member Function Documentation

◆ addCallback()

template<typename CallbackType , typename EventBitflagType >

void xrt::auxiliary::util::GenericCallbacks< CallbackType, EventBitflagType >::addCallback	(	CallbackType	callback,
		mask_t	event_mask,
		void *	userdata
	)

inline

Add a new callback entry with the given callback function pointer, event mask, and user data.

New callback entries are always added at the end of the collection.

Referenced by android_lifecycle_callbacks::android_lifecycle_callbacks_register_callback().

◆ contains()

template<typename CallbackType , typename EventBitflagType >

bool xrt::auxiliary::util::GenericCallbacks< CallbackType, EventBitflagType >::contains	(	CallbackType	callback,
		mask_t	event_mask,
		void *	userdata
	)

inline

See if the collection contains at least one matching callback.

Parameters

callback	The callback function pointer. Tested for equality with each callback entry.
event_mask	The callback event mask. Tested for equality with each callback entry.
userdata	The opaque user data pointer. Tested for equality with each callback entry.

Returns: true if a matching callback is found.

◆ invokeCallbacks()

template<typename CallbackType , typename EventBitflagType >

template<typename F >

int xrt::auxiliary::util::GenericCallbacks< CallbackType, EventBitflagType >::invokeCallbacks	(	EventBitflagType	event,
		F &&	invoker
	)

inline

Invokes the callbacks, by passing the ones we should run to your "invoker" to add any desired context/event data and forward the call.

Callbacks are called in order, filtering out those whose event mask does not include the given event.

Parameters

event	The event type to invoke callbacks for.
invoker	A function/functor accepting the event, a callback function pointer, and the callback entry's userdata as parameters, and returning true if the callback should be removed from the collection. It is assumed that the invoker will add any additional context or event data and call the provided callback.

Typically, a lambda with some captures and a single return statement will be sufficient for an invoker.

Returns: the number of callbacks run

◆ removeCallback()

template<typename CallbackType , typename EventBitflagType >

int xrt::auxiliary::util::GenericCallbacks< CallbackType, EventBitflagType >::removeCallback	(	CallbackType	callback,
		mask_t	event_mask,
		void *	userdata,
		unsigned int	num_skip = `0`,
		int	max_remove = `-1`
	)

inline

Remove some number of callback entries matching the given callback function pointer, event mask, and user data.

Parameters

callback	The callback function pointer. Tested for equality with each callback entry.
event_mask	The callback event mask. Tested for equality with each callback entry.
userdata	The opaque user data pointer. Tested for equality with each callback entry.
num_skip	The number of matches to skip before starting to remove callbacks. Defaults to 0.
max_remove	The number of matches to remove, or negative if no limit. Defaults to -1.

Returns: the number of callbacks removed.

Referenced by android_lifecycle_callbacks::android_lifecycle_callbacks_remove_callback().

The documentation for this struct was generated from the following file:

auxiliary/util/u_generic_callbacks.hpp

Public Types

Public Member Functions

Detailed Description

Member Function Documentation

◆ addCallback()

◆ contains()

◆ invokeCallbacks()

◆ removeCallback()