// Copyright (c) 2024, Google Inc.
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//
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//
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// Author: Maxim Lifantsev
//
// Thread-safe logging routines that do not allocate any memory or
// acquire any locks, and can therefore be used by low-level memory
// allocation and synchronization code.

#ifndef GLOG_RAW_LOGGING_H
#define GLOG_RAW_LOGGING_H

#if defined(GLOG_USE_GLOG_EXPORT)
#  include "glog/export.h"
#endif

#if !defined(GLOG_EXPORT)
#  error <glog/raw_logging.h> was not included correctly. See the documentation for how to consume the library.
#endif

#include "glog/log_severity.h"
#include "glog/vlog_is_on.h"

namespace google {

// This is similar to LOG(severity) << format... and VLOG(level) << format..,
// but
// * it is to be used ONLY by low-level modules that can't use normal LOG()
// * it is desiged to be a low-level logger that does not allocate any
//   memory and does not need any locks, hence:
// * it logs straight and ONLY to STDERR w/o buffering
// * it uses an explicit format and arguments list
// * it will silently chop off really long message strings
// Usage example:
//   RAW_LOG(ERROR, "Failed foo with %i: %s", status, error);
//   RAW_VLOG(3, "status is %i", status);
// These will print an almost standard log lines like this to stderr only:
//   E20200821 211317 file.cc:123] RAW: Failed foo with 22: bad_file
//   I20200821 211317 file.cc:142] RAW: status is 20
#define RAW_LOG(severity, ...)         \
  do {                                 \
    switch (google::GLOG_##severity) { \
      case 0:                          \
        RAW_LOG_INFO(__VA_ARGS__);     \
        break;                         \
      case 1:                          \
        RAW_LOG_WARNING(__VA_ARGS__);  \
        break;                         \
      case 2:                          \
        RAW_LOG_ERROR(__VA_ARGS__);    \
        break;                         \
      case 3:                          \
        RAW_LOG_FATAL(__VA_ARGS__);    \
        break;                         \
      default:                         \
        break;                         \
    }                                  \
  } while (0)

// The following STRIP_LOG testing is performed in the header file so that it's
// possible to completely compile out the logging code and the log messages.
#if !defined(STRIP_LOG) || STRIP_LOG == 0
#  define RAW_VLOG(verboselevel, ...) \
    do {                              \
      if (VLOG_IS_ON(verboselevel)) { \
        RAW_LOG_INFO(__VA_ARGS__);    \
      }                               \
    } while (0)
#else
#  define RAW_VLOG(verboselevel, ...) RawLogStub__(0, __VA_ARGS__)
#endif  // STRIP_LOG == 0

#if !defined(STRIP_LOG) || STRIP_LOG == 0
#  define RAW_LOG_INFO(...) \
    google::RawLog__(google::GLOG_INFO, __FILE__, __LINE__, __VA_ARGS__)
#else
#  define RAW_LOG_INFO(...) google::RawLogStub__(0, __VA_ARGS__)
#endif  // STRIP_LOG == 0

#if !defined(STRIP_LOG) || STRIP_LOG <= 1
#  define RAW_LOG_WARNING(...) \
    google::RawLog__(google::GLOG_WARNING, __FILE__, __LINE__, __VA_ARGS__)
#else
#  define RAW_LOG_WARNING(...) google::RawLogStub__(0, __VA_ARGS__)
#endif  // STRIP_LOG <= 1

#if !defined(STRIP_LOG) || STRIP_LOG <= 2
#  define RAW_LOG_ERROR(...) \
    google::RawLog__(google::GLOG_ERROR, __FILE__, __LINE__, __VA_ARGS__)
#else
#  define RAW_LOG_ERROR(...) google::RawLogStub__(0, __VA_ARGS__)
#endif  // STRIP_LOG <= 2

#if !defined(STRIP_LOG) || STRIP_LOG <= 3
#  define RAW_LOG_FATAL(...) \
    google::RawLog__(google::GLOG_FATAL, __FILE__, __LINE__, __VA_ARGS__)
#else
#  define RAW_LOG_FATAL(...)                \
    do {                                    \
      google::RawLogStub__(0, __VA_ARGS__); \
      exit(EXIT_FAILURE);                   \
    } while (0)
#endif  // STRIP_LOG <= 3

// Similar to CHECK(condition) << message,
// but for low-level modules: we use only RAW_LOG that does not allocate memory.
// We do not want to provide args list here to encourage this usage:
//   if (!cond)  RAW_LOG(FATAL, "foo ...", hard_to_compute_args);
// so that the args are not computed when not needed.
#define RAW_CHECK(condition, message)                             \
  do {                                                            \
    if (!(condition)) {                                           \
      RAW_LOG(FATAL, "Check %s failed: %s", #condition, message); \
    }                                                             \
  } while (0)

// Debug versions of RAW_LOG and RAW_CHECK
#ifndef NDEBUG

#  define RAW_DLOG(severity, ...) RAW_LOG(severity, __VA_ARGS__)
#  define RAW_DCHECK(condition, message) RAW_CHECK(condition, message)

#else  // NDEBUG

#  define RAW_DLOG(severity, ...) \
    while (false) RAW_LOG(severity, __VA_ARGS__)
#  define RAW_DCHECK(condition, message) \
    while (false) RAW_CHECK(condition, message)

#endif  // NDEBUG

// Stub log function used to work around for unused variable warnings when
// building with STRIP_LOG > 0.
static inline void RawLogStub__(int /* ignored */, ...) {}

// Helper function to implement RAW_LOG and RAW_VLOG
// Logs format... at "severity" level, reporting it
// as called from file:line.
// This does not allocate memory or acquire locks.
GLOG_EXPORT void RawLog__(LogSeverity severity, const char* file, int line,
                          const char* format, ...)
#if defined(__has_attribute)
#  if __has_attribute(used)
    __attribute__((__format__(__printf__, 4, 5)))
#  endif
#endif
    ;
}  // namespace google

#endif  // GLOG_RAW_LOGGING_H
