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Add support for deferred executors. (#14859)

* Add support for deferred executors.

* More docs.

* Include from quantum.h

* Cleanup.

* Parameter checks

* Comments.

* qmk format-c

* I accidentally a few words.

* API name change.

* Apply suggestions from code review

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>

* Review comments.

* qmk format-c

* Review comments.

Co-authored-by: Sergey Vlasov <sigprof@gmail.com>
This commit is contained in:
Nick Brassel 2021-11-16 05:21:09 +11:00 committed by GitHub
parent b3ee124da6
commit 36d123e9c5
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9 changed files with 286 additions and 0 deletions

152
quantum/deferred_exec.c Normal file
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@ -0,0 +1,152 @@
// Copyright 2021 Nick Brassel (@tzarc)
// SPDX-License-Identifier: GPL-2.0-or-later
#include <stddef.h>
#include <timer.h>
#include <deferred_exec.h>
#ifndef MAX_DEFERRED_EXECUTORS
# define MAX_DEFERRED_EXECUTORS 8
#endif
typedef struct deferred_executor_t {
deferred_token token;
uint32_t trigger_time;
deferred_exec_callback callback;
void * cb_arg;
} deferred_executor_t;
static deferred_token current_token = 0;
static uint32_t last_deferred_exec_check = 0;
static deferred_executor_t executors[MAX_DEFERRED_EXECUTORS] = {0};
static inline bool token_can_be_used(deferred_token token) {
if (token == INVALID_DEFERRED_TOKEN) {
return false;
}
for (int i = 0; i < MAX_DEFERRED_EXECUTORS; ++i) {
if (executors[i].token == token) {
return false;
}
}
return true;
}
static inline deferred_token allocate_token(void) {
deferred_token first = ++current_token;
while (!token_can_be_used(current_token)) {
++current_token;
if (current_token == first) {
// If we've looped back around to the first, everything is already allocated (yikes!). Need to exit with a failure.
return INVALID_DEFERRED_TOKEN;
}
}
return current_token;
}
deferred_token defer_exec(uint32_t delay_ms, deferred_exec_callback callback, void *cb_arg) {
// Ignore queueing if it's a zero-time delay, or invalid callback
if (delay_ms == 0 || !callback) {
return INVALID_DEFERRED_TOKEN;
}
// Find an unused slot and claim it
for (int i = 0; i < MAX_DEFERRED_EXECUTORS; ++i) {
deferred_executor_t *entry = &executors[i];
if (entry->token == INVALID_DEFERRED_TOKEN) {
// Work out the new token value, dropping out if none were available
deferred_token token = allocate_token();
if (token == INVALID_DEFERRED_TOKEN) {
return false;
}
// Set up the executor table entry
entry->token = current_token;
entry->trigger_time = timer_read32() + delay_ms;
entry->callback = callback;
entry->cb_arg = cb_arg;
return current_token;
}
}
// None available
return INVALID_DEFERRED_TOKEN;
}
bool extend_deferred_exec(deferred_token token, uint32_t delay_ms) {
// Ignore queueing if it's a zero-time delay, or the token is not valid
if (delay_ms == 0 || token == INVALID_DEFERRED_TOKEN) {
return false;
}
// Find the entry corresponding to the token
for (int i = 0; i < MAX_DEFERRED_EXECUTORS; ++i) {
deferred_executor_t *entry = &executors[i];
if (entry->token == token) {
// Found it, extend the delay
entry->trigger_time = timer_read32() + delay_ms;
return true;
}
}
// Not found
return false;
}
bool cancel_deferred_exec(deferred_token token) {
// Ignore request if the token is not valid
if (token == INVALID_DEFERRED_TOKEN) {
return false;
}
// Find the entry corresponding to the token
for (int i = 0; i < MAX_DEFERRED_EXECUTORS; ++i) {
deferred_executor_t *entry = &executors[i];
if (entry->token == token) {
// Found it, cancel and clear the table entry
entry->token = INVALID_DEFERRED_TOKEN;
entry->trigger_time = 0;
entry->callback = NULL;
entry->cb_arg = NULL;
return true;
}
}
// Not found
return false;
}
void deferred_exec_task(void) {
uint32_t now = timer_read32();
// Throttle only once per millisecond
if (((int32_t)TIMER_DIFF_32(now, last_deferred_exec_check)) > 0) {
last_deferred_exec_check = now;
// Run through each of the executors
for (int i = 0; i < MAX_DEFERRED_EXECUTORS; ++i) {
deferred_executor_t *entry = &executors[i];
// Check if we're supposed to execute this entry
if (entry->token != INVALID_DEFERRED_TOKEN && ((int32_t)TIMER_DIFF_32(entry->trigger_time, now)) <= 0) {
// Invoke the callback and work work out if we should be requeued
uint32_t delay_ms = entry->callback(entry->trigger_time, entry->cb_arg);
// Update the trigger time if we have to repeat, otherwise clear it out
if (delay_ms > 0) {
// Intentionally add just the delay to the existing trigger time -- this ensures the next
// invocation is with respect to the previous trigger, rather than when it got to execution. Under
// normal circumstances this won't cause issue, but if another executor is invoked that takes a
// considerable length of time, then this ensures best-effort timing between invocations.
entry->trigger_time += delay_ms;
} else {
// If it was zero, then the callback is cancelling repeated execution. Free up the slot.
entry->token = INVALID_DEFERRED_TOKEN;
entry->trigger_time = 0;
entry->callback = NULL;
entry->cb_arg = NULL;
}
}
}
}
}

38
quantum/deferred_exec.h Normal file
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// Copyright 2021 Nick Brassel (@tzarc)
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <stdbool.h>
#include <stdint.h>
// A token that can be used to cancel an existing deferred execution.
typedef uint8_t deferred_token;
#define INVALID_DEFERRED_TOKEN 0
// Callback to execute.
// -- Parameter trigger_time: the intended trigger time to execute the callback -- equivalent time-space as timer_read32()
// cb_arg: the callback argument specified when enqueueing the deferred executor
// -- Return value: Non-zero re-queues the callback to execute after the returned number of milliseconds. Zero cancels repeated execution.
typedef uint32_t (*deferred_exec_callback)(uint32_t trigger_time, void *cb_arg);
// Configures the supplied deferred executor to be executed after the required number of milliseconds.
// -- Parameter delay_ms: the number of milliseconds before executing the callback
// -- callback: the executor to invoke
// -- cb_arg: the argument to pass to the executor, may be NULL if unused by the executor
// -- Return value: a token usable for cancellation, or INVALID_DEFERRED_TOKEN if an error occurred
deferred_token defer_exec(uint32_t delay_ms, deferred_exec_callback callback, void *cb_arg);
// Allows for extending the timeframe before an existing deferred execution is invoked.
// -- Parameter token: the returned value from defer_exec for the deferred execution you wish to extend.
// -- delay_ms: the new delay (with respect to the current time)
// -- Return value: if the token was found, and the delay was extended
bool extend_deferred_exec(deferred_token token, uint32_t delay_ms);
// Allows for cancellation of an existing deferred execution.
// -- Parameter token: the returned value from defer_exec for the deferred execution you wish to cancel.
// -- Return value: if the token was found, and the executor was cancelled
bool cancel_deferred_exec(deferred_token token);
// Forward declaration for the main loop in order to execute any deferred executors. Should not be invoked by keyboard/user code.
void deferred_exec_task(void);

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@ -43,6 +43,10 @@ void protocol_task(void) {
protocol_post_task();
}
#ifdef DEFERRED_EXEC_ENABLE
void deferred_exec_task(void);
#endif // DEFERRED_EXEC_ENABLE
/** \brief Main
*
* FIXME: Needs doc
@ -58,6 +62,12 @@ int main(void) {
/* Main loop */
while (true) {
protocol_task();
#ifdef DEFERRED_EXEC_ENABLE
// Run deferred executions
deferred_exec_task();
#endif // DEFERRED_EXEC_ENABLE
housekeeping_task();
}
}

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@ -54,6 +54,10 @@
#include <stddef.h>
#include <stdlib.h>
#ifdef DEFERRED_EXEC_ENABLE
# include "deferred_exec.h"
#endif
extern layer_state_t default_layer_state;
#ifndef NO_ACTION_LAYER