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esphome/esphome/components/logger/task_log_buffer_libretiny.h
2026-02-11 15:43:55 +00:00

104 lines
4.3 KiB
C++

#pragma once
#ifdef USE_LIBRETINY
#include "esphome/core/defines.h"
#include "esphome/core/helpers.h"
#ifdef USE_ESPHOME_TASK_LOG_BUFFER
#include <cstdarg>
#include <cstddef>
#include <cstring>
#include <FreeRTOS.h>
#include <semphr.h>
#include <task.h>
namespace esphome::logger {
/**
* @brief Task log buffer for LibreTiny platform using mutex-protected circular buffer.
*
* Why This Is Critical:
* Without thread-safe logging, when a non-main task logs a message, it would directly
* call the logger which builds a protobuf message in a shared buffer. If this happens
* while the main loop is also using that buffer (e.g., sending API responses), the
* buffer gets corrupted, sending garbage to all connected API clients and breaking
* their connections. This buffer ensures log messages from other tasks are queued
* safely and processed only from the main loop.
*
* Threading Model: Multi-Producer Single-Consumer (MPSC)
* - Multiple FreeRTOS tasks can safely call send_message_thread_safe() concurrently
* - Only the main loop task calls borrow_message_main_loop() and release_message_main_loop()
*
* This uses a simple circular buffer protected by a FreeRTOS mutex. Unlike ESP32,
* LibreTiny lacks hardware atomic support (ARM968E-S has no LDREX/STREX), so we use
* a volatile counter for fast has_messages() checks instead of atomics.
*
* Design:
* - Variable-size messages with header + text stored contiguously (NOSPLIT style)
* - FreeRTOS mutex protects all buffer operations
* - Volatile counter enables fast has_messages() without lock overhead
* - If message doesn't fit at end, padding is added and message wraps to start
*/
class TaskLogBuffer {
public:
// Structure for a log message header (text data follows immediately after)
struct LogMessage {
const char *tag; // We store the pointer, assuming tags are static
char thread_name[16]; // Store thread name directly (only used for non-main threads)
uint16_t text_length; // Length of the message text (up to ~64KB)
uint16_t line; // Source code line number
uint8_t level; // Log level (0-7)
// Methods for accessing message contents
inline char *text_data() { return reinterpret_cast<char *>(this) + sizeof(LogMessage); }
inline const char *text_data() const { return reinterpret_cast<const char *>(this) + sizeof(LogMessage); }
};
// Padding marker level to indicate wrap-around point (stored in LogMessage.level field)
// Valid log levels are 0-7, so 0xFF cannot be a real message
static constexpr uint8_t PADDING_MARKER_LEVEL = 0xFF;
// Constructor that takes a total buffer size
explicit TaskLogBuffer(size_t total_buffer_size);
~TaskLogBuffer();
// NOT thread-safe - borrow a message from the buffer, only call from main loop
bool borrow_message_main_loop(LogMessage *&message, uint16_t &text_length);
// NOT thread-safe - release a message buffer, only call from main loop
void release_message_main_loop();
// Thread-safe - send a message to the buffer from any thread
bool send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
const char *format, va_list args);
// Fast check using volatile counter - no lock needed
// Worst case: miss a message for one loop iteration (~8ms at 7000 loops/min)
inline bool HOT has_messages() const { return this->message_count_ != 0; }
// Get the total buffer size in bytes
inline size_t size() const { return this->size_; }
private:
// Calculate total size needed for a message (header + text + null terminator)
static inline size_t message_total_size(size_t text_length) { return sizeof(LogMessage) + text_length + 1; }
// Calculate available contiguous space at write position
size_t available_contiguous_space() const;
uint8_t *storage_{nullptr}; // Pointer to allocated memory
size_t size_{0}; // Size of allocated memory
size_t head_{0}; // Write position
size_t tail_{0}; // Read position
SemaphoreHandle_t mutex_{nullptr}; // FreeRTOS mutex for thread safety
volatile uint16_t message_count_{0}; // Fast check counter (dirty read OK)
size_t current_message_size_{0}; // Size of currently borrowed message
};
} // namespace esphome::logger
#endif // USE_ESPHOME_TASK_LOG_BUFFER
#endif // USE_LIBRETINY