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/*
* Copyright 2023 jacqueline <me@jacqueline.id.au>
*
* SPDX-License-Identifier: GPL-3.0-only
*/
#pragma once
#include <atomic>
#include <functional>
#include <future>
#include <memory>
#include <memory_resource>
#include <string>
#include "esp_heap_caps.h"
#include "freertos/FreeRTOS.h"
#include "freertos/portmacro.h"
#include "freertos/projdefs.h"
#include "freertos/queue.h"
#include "freertos/task.h"
#include "span.hpp"
namespace tasks {
/*
* Enumeration of every task (basically a thread) started within the firmware.
* These are centralised so that it is easier to reason about the relative
* priorities of tasks, as well as the amount and location of memory allocated
* to each one.
*/
enum class Type {
// The main UI task. This runs the LVGL main loop.
kUi,
// The main audio pipeline task. Decodes files into PCM stream.
kAudioDecoder,
// Second audio task. Converts the PCM stream into one suitable for the
// current output (e.g. downsampling for bluetooth).
kAudioConverter,
// Task for running database queries.
kDatabase,
// Task for async background work
kBackgroundWorker,
};
template <Type t>
auto Name() -> std::pmr::string;
template <Type t>
auto AllocateStack() -> cpp::span<StackType_t>;
template <Type t>
auto Priority() -> UBaseType_t;
auto PersistentMain(void* fn) -> void;
template <Type t>
auto StartPersistent(const std::function<void(void)>& fn) -> void {
StaticTask_t* task_buffer = static_cast<StaticTask_t*>(heap_caps_malloc(
sizeof(StaticTask_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT));
cpp::span<StackType_t> stack = AllocateStack<t>();
xTaskCreateStatic(&PersistentMain, Name<t>().c_str(), stack.size(),
new std::function<void(void)>(fn), Priority<t>(),
stack.data(), task_buffer);
}
template <Type t>
auto StartPersistent(BaseType_t core, const std::function<void(void)>& fn)
-> void {
StaticTask_t* task_buffer = static_cast<StaticTask_t*>(heap_caps_malloc(
sizeof(StaticTask_t), MALLOC_CAP_INTERNAL | MALLOC_CAP_8BIT));
cpp::span<StackType_t> stack = AllocateStack<t>();
xTaskCreateStaticPinnedToCore(&PersistentMain, Name<t>().c_str(),
stack.size(), new std::function<void(void)>(fn),
Priority<t>(), stack.data(), task_buffer, core);
}
class WorkerPool {
private:
QueueHandle_t queue_;
using WorkItem = std::function<void(void)>*;
static auto Main(void* instance);
public:
WorkerPool();
~WorkerPool();
/*
* Schedules the given function to be executed on the worker task, and
* asynchronously returns the result as a future.
*/
template <typename T>
auto Dispatch(const std::function<T(void)> fn) -> std::future<T> {
std::shared_ptr<std::promise<T>> promise =
std::make_shared<std::promise<T>>();
WorkItem item =
new std::function([=]() { promise->set_value(std::invoke(fn)); });
xQueueSend(queue_, &item, portMAX_DELAY);
return promise->get_future();
}
WorkerPool(const WorkerPool&) = delete;
WorkerPool& operator=(const WorkerPool&) = delete;
};
/* Specialisation of Evaluate for functions that return nothing. */
template <>
auto WorkerPool::Dispatch(const std::function<void(void)> fn)
-> std::future<void>;
} // namespace tasks
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