logging.h

#pragma once

#include <syscall.h>
#include <unistd.h>

#include <cassert>
#include <chrono>

#include "config.h"

#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)

namespace madfs {
struct FatalException : public std::exception {};
}  // namespace madfs

/*
 * The following macros used for assertion and logging
 * Defined as macros since we want to have access to __FILE__ and __LINE__
 */
#define MADFS_FPRINTF(file, fmt, ...)                                   \
  do {                                                                  \
    auto now = std::chrono::high_resolution_clock::now();               \
    std::chrono::duration<double> sec = now.time_since_epoch();         \
    const char *s = strrchr(__FILE__, '/');                             \
    const char *caller_filename = s ? s + 1 : __FILE__;                 \
    fprintf(file, "[Thread %d] %f [%14s:%-3d] " fmt "\n", ::madfs::tid, \
            sec.count(), caller_filename, __LINE__, ##__VA_ARGS__);     \
  } while (0)

// PANIC_IF is active for both debug and release modes
#define PANIC_IF(expr, msg, ...)                                 \
  do {                                                           \
    if (likely(!(expr))) break;                                  \
    MADFS_FPRINTF(stderr, "[PANIC] " msg ": %m", ##__VA_ARGS__); \
    assert(false);                                               \
    throw ::madfs::FatalException();                             \
  } while (0)
#define PANIC(msg, ...) PANIC_IF(true, msg, ##__VA_ARGS__)

// LOG_* are not active in release mode
#define MADFS_LOG(level, msg, ...)                                         \
  do {                                                                     \
    if constexpr (!::madfs::BuildOptions::debug) break;                    \
    if (level < ::madfs::runtime_options.log_level) break;                 \
    constexpr const char *level_str_arr[] = {                              \
        "[\u001b[37mTRACE\u001b[0m]",                                      \
        "[\u001b[32mDEBUG\u001b[0m]",                                      \
        "[\u001b[34mINFO\u001b[0m] ",                                      \
        "[\u001b[31mWARN\u001b[0m] ",                                      \
    };                                                                     \
    constexpr const char *level_str = level_str_arr[level];                \
    if (::madfs::log_file == nullptr) ::madfs::log_file = stderr;          \
    MADFS_FPRINTF(::madfs::log_file, "%s " msg, level_str, ##__VA_ARGS__); \
  } while (0)

#define LOG_TRACE(msg, ...) MADFS_LOG(0, msg, ##__VA_ARGS__)
#define LOG_DEBUG(msg, ...) MADFS_LOG(1, msg, ##__VA_ARGS__)
#define LOG_INFO(msg, ...) MADFS_LOG(2, msg, ##__VA_ARGS__)
#define LOG_WARN(msg, ...) MADFS_LOG(3, msg, ##__VA_ARGS__)

namespace madfs {
inline __attribute__((tls_model("initial-exec"))) thread_local const pid_t tid =
    static_cast<pid_t>(syscall(SYS_gettid));
inline FILE *log_file = stderr;
}  // namespace madfs