/* * Copyright (c) 2017 Apple Inc. All Rights Reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #ifndef _SEC_ACTION_H_ #define _SEC_ACTION_H_ #include <dispatch/dispatch.h> /* * Simple dispatch-based mechanism to coalesce high-frequency actions like * notifications. Sample usage: * * static void * notify_frequent_event(void) * { * static dispatch_once_t once; * static sec_action_t action; * * dispatch_once(&once, ^{ * action = sec_action_create("frequent_event", 2); * sec_action_set_handler(action, ^{ * (void)notify_post("com.apple.frequent_event"); * }); * }); * * sec_action_perform(action); * } * * The above will prevent com.apple.frequent_event from being posted more than * once every 2 seconds. For example, if notify_frequent_event is called 1000 times * over the span of 1.9s, the handler will be called twice, at 0s and 2s (approx). * * Default behavior is to perform actions on a queue with the same QOS as the caller. * If the action should be performed on a specific serial queue, the function * sec_action_create_with_queue can alternatively be used. */ typedef dispatch_source_t sec_action_t; __BEGIN_DECLS DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NONNULL_ALL DISPATCH_NOTHROW sec_action_t sec_action_create(const char *label, uint64_t interval); DISPATCH_MALLOC DISPATCH_RETURNS_RETAINED DISPATCH_WARN_RESULT DISPATCH_NOTHROW sec_action_t sec_action_create_with_queue(dispatch_queue_t queue, const char *label, uint64_t interval); DISPATCH_NONNULL_ALL DISPATCH_NOTHROW void sec_action_set_handler(sec_action_t action, dispatch_block_t handler); DISPATCH_NONNULL_ALL void sec_action_perform(sec_action_t action); __END_DECLS #endif /* _SEC_ACTION_H_ */