Ken Van Hoeylandt
133 lines
3.3 KiB
C++
133 lines
3.3 KiB
C++
/**
|
|
* Dispatcher is a thread-safe code execution queue.
|
|
*/
|
|
#pragma once
|
|
|
|
#include "EventGroup.h"
|
|
#include "Mutex.h"
|
|
#include "kernel/Kernel.h"
|
|
|
|
#ifdef ESP_PLATFORM
|
|
#include <esp_log.h>
|
|
#endif
|
|
|
|
#include <functional>
|
|
#include <memory>
|
|
#include <queue>
|
|
|
|
namespace tt {
|
|
|
|
/**
|
|
* A thread-safe way to defer code execution.
|
|
* Generally, one task would dispatch the execution,
|
|
* while the other thread consumes and executes the work.
|
|
*/
|
|
class Dispatcher final {
|
|
|
|
static constexpr auto TAG = "Dispatcher";
|
|
static constexpr EventBits_t BACKPRESSURE_WARNING_COUNT = 100U;
|
|
static constexpr EventBits_t WAIT_FLAG = 1U;
|
|
|
|
public:
|
|
|
|
typedef std::function<void()> Function;
|
|
|
|
private:
|
|
|
|
Mutex mutex;
|
|
std::queue<Function> queue = {};
|
|
EventGroup eventFlag;
|
|
bool shutdown = false;
|
|
|
|
public:
|
|
|
|
explicit Dispatcher() = default;
|
|
|
|
~Dispatcher() {
|
|
shutdown = true;
|
|
if (mutex.lock()) {
|
|
mutex.unlock();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Queue a function to be consumed elsewhere.
|
|
* @param[in] function the function to execute elsewhere
|
|
* @param[in] timeout lock acquisition timeout
|
|
* @return true if dispatching was successful (timeout not reached)
|
|
*/
|
|
bool dispatch(Function function, TickType_t timeout = kernel::MAX_TICKS) {
|
|
// Mutate
|
|
if (!mutex.lock(timeout)) {
|
|
#ifdef ESP_PLATFORM
|
|
ESP_LOGE(TAG, "Mutex acquisition timeout");
|
|
#endif
|
|
return false;
|
|
}
|
|
|
|
if (shutdown) {
|
|
return false;
|
|
}
|
|
|
|
queue.push(std::move(function));
|
|
if (queue.size() == BACKPRESSURE_WARNING_COUNT) {
|
|
#ifdef ESP_PLATFORM
|
|
ESP_LOGW(TAG, "Backpressure: You're not consuming fast enough (100 queued)");
|
|
#endif
|
|
}
|
|
mutex.unlock();
|
|
if (!eventFlag.set(WAIT_FLAG)) {
|
|
#ifdef ESP_PLATFORM
|
|
ESP_LOGE(TAG, "Failed to set flag");
|
|
#endif
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Consume 1 or more dispatched function (if any) until the queue is empty.
|
|
* @warning The timeout is only the wait time before consuming the message! It is not a limit to the total execution time when calling this method.
|
|
* @param[in] timeout the ticks to wait for a message
|
|
* @return the amount of messages that were consumed
|
|
*/
|
|
uint32_t consume(TickType_t timeout = kernel::MAX_TICKS) {
|
|
// Wait for signal
|
|
if (!eventFlag.wait(WAIT_FLAG, false, true, timeout)) {
|
|
return 0;
|
|
}
|
|
|
|
if (shutdown) {
|
|
return 0;
|
|
}
|
|
|
|
// Mutate
|
|
bool processing = true;
|
|
uint32_t consumed = 0;
|
|
do {
|
|
if (mutex.lock(10)) {
|
|
if (!queue.empty()) {
|
|
auto function = queue.front();
|
|
queue.pop();
|
|
consumed++;
|
|
processing = !queue.empty();
|
|
// Don't keep lock as callback might be slow
|
|
mutex.unlock();
|
|
function();
|
|
} else {
|
|
processing = false;
|
|
mutex.unlock();
|
|
}
|
|
} else {
|
|
#ifdef ESP_PLATFORM
|
|
ESP_LOGW(TAG, "Mutex acquisition timeout");
|
|
#endif
|
|
}
|
|
|
|
} while (processing && !shutdown);
|
|
|
|
return consumed;
|
|
}
|
|
};
|
|
|
|
} // namespace
|