rocksdb/util/stderr_logger.cc

64 lines
2.2 KiB
C++

// Copyright (c) Meta Platforms, Inc. and affiliates.
//
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#include "util/stderr_logger.h"
#include "port/malloc.h"
#include "port/sys_time.h"
namespace ROCKSDB_NAMESPACE {
StderrLogger::~StderrLogger() {
if (log_prefix != nullptr) {
free((void*)log_prefix);
}
}
void StderrLogger::Logv(const char* format, va_list ap) {
const uint64_t thread_id = Env::Default()->GetThreadID();
port::TimeVal now_tv;
port::GetTimeOfDay(&now_tv, nullptr);
const time_t seconds = now_tv.tv_sec;
struct tm t;
port::LocalTimeR(&seconds, &t);
// The string we eventually log has three parts: the context (time, thread),
// optional user-supplied prefix, and the actual log message (the "suffix").
//
// We compute their lengths so that we can allocate a buffer big enough to
// print it. The context string (with the date and thread id) is really only
// 44 bytes, but we allocate 50 to be safe.
//
// ctx_len = 44 = ( 4+ 1+ 2+1+2+ 1+2+ 1+2+ 1+ 2+1+6+ 1+16+1)
const char* ctx_prefix_fmt = "%04d/%02d/%02d-%02d:%02d:%02d.%06d %llx %s";
size_t ctx_len = 50;
va_list ap_copy;
va_copy(ap_copy, ap);
const size_t log_suffix_len = vsnprintf(nullptr, 0, format, ap_copy);
va_end(ap_copy);
// Allocate space for the context, log_prefix, and log itself
// Extra byte for null termination
size_t buf_len = ctx_len + log_prefix_len + log_suffix_len + 1;
std::unique_ptr<char[]> buf(new char[buf_len]);
// If the logger was created without a prefix, the prefix is a nullptr
const char* prefix = log_prefix == nullptr ? "" : log_prefix;
// Write out the context and prefix string
int written =
snprintf(buf.get(), ctx_len + log_prefix_len, ctx_prefix_fmt,
t.tm_year + 1900, t.tm_mon + 1, t.tm_mday, t.tm_hour, t.tm_min,
t.tm_sec, static_cast<int>(now_tv.tv_usec),
static_cast<long long unsigned int>(thread_id), prefix);
written += vsnprintf(buf.get() + written, log_suffix_len, format, ap);
buf[written] = '\0';
fprintf(stderr, "%s%c", buf.get(), '\n');
}
} // namespace ROCKSDB_NAMESPACE