deferred_exec.h

  1// Copyright 2021 Nick Brassel (@tzarc)
  2// SPDX-License-Identifier: GPL-2.0-or-later
  3
  4#pragma once
  5
  6#include <stdbool.h>
  7#include <stdint.h>
  8#include <stdlib.h>
  9
 10//------------------------------------
 11// Common
 12//------------------------------------
 13
 14/**
 15 * @typedef A token that can be used to cancel or extend an existing deferred execution.
 16 */
 17typedef uint8_t deferred_token;
 18
 19/**
 20 * @def The constant used to denote an invalid deferred execution token.
 21 */
 22#define INVALID_DEFERRED_TOKEN 0
 23
 24/**
 25 * @typedef Callback to execute.
 26 * @param trigger_time[in] the intended trigger time to execute the callback -- equivalent time-space as timer_read32()
 27 * @param cb_arg[in] the callback argument specified when enqueueing the deferred executor
 28 * @return non-zero re-queues the callback to execute after the returned number of milliseconds. Zero cancels repeated execution.
 29 */
 30typedef uint32_t (*deferred_exec_callback)(uint32_t trigger_time, void *cb_arg);
 31
 32//------------------------------------
 33// Basic API: used by user-mode code, guaranteed to not collide with core deferred execution
 34//------------------------------------
 35
 36/**
 37 * Configures the supplied deferred executor to be executed after the required number of milliseconds.
 38 *
 39 * @param delay_ms[in] the number of milliseconds before executing the callback
 40 * @param callback[in] the executor to invoke
 41 * @param cb_arg[in] the argument to pass to the executor, may be NULL if unused by the executor
 42 * @return a token usable for extension/cancellation, or INVALID_DEFERRED_TOKEN if an error occurred
 43 */
 44deferred_token defer_exec(uint32_t delay_ms, deferred_exec_callback callback, void *cb_arg);
 45
 46/**
 47 * Allows for extending the timeframe before an existing deferred execution is invoked.
 48 *
 49 * @param token[in] the returned value from defer_exec for the deferred execution you wish to extend
 50 * @param delay_ms[in] the number of milliseconds before executing the callback
 51 * @return true if the token was extended successfully, otherwise false
 52 */
 53bool extend_deferred_exec(deferred_token token, uint32_t delay_ms);
 54
 55/**
 56 * Allows for cancellation of an existing deferred execution.
 57 *
 58 * @param token[in] the returned value from defer_exec for the deferred execution you wish to cancel
 59 * @return true if the token was cancelled successfully, otherwise false
 60 */
 61bool cancel_deferred_exec(deferred_token token);
 62
 63/**
 64 * Forward declaration for the main loop in order to execute any deferred executors. Should not be invoked by keyboard/user code.
 65 */
 66void deferred_exec_task(void);
 67
 68//------------------------------------
 69// Advanced API: used when a custom-allocated table is used, primarily for core code.
 70//------------------------------------
 71
 72/**
 73 * @struct Structure for containing self-hosted deferred executor tables.
 74 * @brief Core-side code can use this to create their own tables without impacting on the use of users' ability to add deferred execution.
 75 *        Code outside deferred_exec.c should not worry about internals of this struct, and should just allocate the required number in an array.
 76 */
 77typedef struct deferred_executor_t {
 78    deferred_token         token;
 79    uint32_t               trigger_time;
 80    deferred_exec_callback callback;
 81    void *                 cb_arg;
 82} deferred_executor_t;
 83
 84/**
 85 * Configures the supplied deferred executor to be executed after the required number of milliseconds.
 86 *
 87 * @param table[in] the custom table used for storage
 88 * @param table_count[in] the number of available items in the table
 89 * @param delay_ms[in] the number of milliseconds before executing the callback
 90 * @param callback[in] the executor to invoke
 91 * @param cb_arg[in] the argument to pass to the executor, may be NULL if unused by the executor
 92 * @return a token usable for extension/cancellation, or INVALID_DEFERRED_TOKEN if an error occurred
 93 */
 94deferred_token defer_exec_advanced(deferred_executor_t *table, size_t table_count, uint32_t delay_ms, deferred_exec_callback callback, void *cb_arg);
 95
 96/**
 97 * Allows for extending the timeframe before an existing deferred execution is invoked.
 98 *
 99 * @param token[in] the returned value from defer_exec for the deferred execution you wish to extend
100 * @param delay_ms[in] the number of milliseconds before executing the callback
101 * @return true if the token was extended successfully, otherwise false
102 */
103bool extend_deferred_exec_advanced(deferred_executor_t *table, size_t table_count, deferred_token token, uint32_t delay_ms);
104
105/**
106 * Allows for cancellation of an existing deferred execution.
107 *
108 * @param token[in] the returned value from defer_exec for the deferred execution you wish to cancel
109 * @return true if the token was cancelled successfully, otherwise false
110 */
111bool cancel_deferred_exec_advanced(deferred_executor_t *table, size_t table_count, deferred_token token);
112
113/**
114 * Forward declaration for the main loop in order to execute any custom table deferred executors. Should not be invoked by keyboard/user code.
115 * Needed for any custom-allocated deferred execution tables. Any core tasks should add appropriate invocation to quantum/main.c.
116 *
117 * @param table[in] the custom table used for storage
118 * @param table_count[in] the number of available items in the table
119 * @param last_execution_time[in,out] the last execution time -- this will be checked first to determine if execution is needed, and updated if execution occurred
120 */
121void deferred_exec_advanced_task(deferred_executor_t *table, size_t table_count, uint32_t *last_execution_time);