task_log_buffer_libretiny.h

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#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 {
 
class TaskLogBufferLibreTiny {
 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 TaskLogBufferLibreTiny(size_t total_buffer_size);
  ~TaskLogBufferLibreTiny();
 
  // NOT thread-safe - borrow a message from the buffer, only call from main loop
  bool borrow_message_main_loop(LogMessage **message, const char **text);
 
  // 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, TaskHandle_t task_handle,
                                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