//

// Copyright 2022 The Abseil Authors.

//

// Licensed under the Apache License, Version 2.0 (the "License");

// you may not use this file except in compliance with the License.

// You may obtain a copy of the License at

//

//      https://www.apache.org/licenses/LICENSE-2.0

//

// Unless required by applicable law or agreed to in writing, software

// distributed under the License is distributed on an "AS IS" BASIS,

// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

// See the License for the specific language governing permissions and

// limitations under the License.

#include "absl/log/internal/log_format.h"

#include <string.h>

#ifdef _MSC_VER

#include <winsock2.h>  // For timeval

#else

#include <sys/time.h>

#endif

#include <cstddef>

#include <cstdint>

#include <limits>

#include <string>

#include <type_traits>

#include "absl/base/config.h"

#include "absl/base/log_severity.h"

#include "absl/base/optimization.h"

#include "absl/log/internal/append_truncated.h"

#include "absl/log/internal/config.h"

#include "absl/log/internal/globals.h"

#include "absl/strings/numbers.h"

#include "absl/strings/str_format.h"

#include "absl/strings/string_view.h"

#include "absl/time/civil_time.h"

#include "absl/time/time.h"

#include "absl/types/span.h"

namespace absl {

ABSL_NAMESPACE_BEGIN

namespace log_internal {

namespace {

// This templated function avoids compiler warnings about tautological

// comparisons when log_internal::Tid is unsigned. It can be replaced with a

// constexpr if once the minimum C++ version Abseil supports is C++17.

template <typename T>

inline std::enable_if_t<!std::is_signed<T>::value>

PutLeadingWhitespace(T tid, char*& p) {

  if (tid < 10) *p++ = ' ';

  if (tid < 100) *p++ = ' ';

  if (tid < 1000) *p++ = ' ';

  if (tid < 10000) *p++ = ' ';

  if (tid < 100000) *p++ = ' ';

  if (tid < 1000000) *p++ = ' ';

}

template <typename T>

inline std::enable_if_t<std::is_signed<T>::value>

PutLeadingWhitespace(T tid, char*& p) {

  if (tid >= 0 && tid < 10) *p++ = ' ';

  if (tid > -10 && tid < 100) *p++ = ' ';

  if (tid > -100 && tid < 1000) *p++ = ' ';

  if (tid > -1000 && tid < 10000) *p++ = ' ';

  if (tid > -10000 && tid < 100000) *p++ = ' ';

  if (tid > -100000 && tid < 1000000) *p++ = ' ';

}

// The fields before the filename are all fixed-width except for the thread ID,

// which is of bounded width.

size_t FormatBoundedFields(absl::LogSeverity severity, absl::Time timestamp,

                           log_internal::Tid tid, absl::Span<char>& buf) {

  constexpr size_t kBoundedFieldsMaxLen =

      sizeof("SMMDD HH:MM:SS.NNNNNN  ") +

      (1 + std::numeric_limits<log_internal::Tid>::digits10 + 1) - sizeof("");

  if (ABSL_PREDICT_FALSE(buf.size() < kBoundedFieldsMaxLen)) {

    // We don't bother trying to truncate these fields if the buffer is too

    // short (or almost too short) because it would require doing a lot more

    // length checking (slow) and it should never happen.  A 15kB buffer should

    // be enough for anyone.  Instead we mark `buf` full without writing

    // anything.

    buf.remove_suffix(buf.size());

    return 0;

  }

  // We can't call absl::LocalTime(), localtime_r(), or anything else here that

  // isn't async-signal-safe. We can only use the time zone if it has already

  // been loaded.

  const absl::TimeZone* tz = absl::log_internal::TimeZone();

  if (ABSL_PREDICT_FALSE(tz == nullptr)) {

    // If a time zone hasn't been set yet because we are logging before the

    // logging library has been initialized, we fallback to a simpler, slower

    // method. Just report the raw Unix time in seconds. We cram this into the

    // normal time format for the benefit of parsers.

    auto tv = absl::ToTimeval(timestamp);

    int snprintf_result = absl::SNPrintF(

        buf.data(), buf.size(), "%c0000 00:00:%02d.%06d %7d ",

        absl::LogSeverityName(severity)[0], static_cast<int>(tv.tv_sec),

        static_cast<int>(tv.tv_usec), static_cast<int>(tid));

    if (snprintf_result >= 0) {

      buf.remove_prefix(static_cast<size_t>(snprintf_result));

      return static_cast<size_t>(snprintf_result);

    }

    return 0;

  }

  char* p = buf.data();

  *p++ = absl::LogSeverityName(severity)[0];

  const absl::TimeZone::CivilInfo ci = tz->At(timestamp);

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.month()), p);

  p += 2;

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.day()), p);

  p += 2;

  *p++ = ' ';

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.hour()), p);

  p += 2;

  *p++ = ':';

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.minute()),

                                       p);

  p += 2;

  *p++ = ':';

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(ci.cs.second()),

                                       p);

  p += 2;

  *p++ = '.';

  const int64_t usecs = absl::ToInt64Microseconds(ci.subsecond);

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs / 10000), p);

  p += 2;

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs / 100 % 100),

                                       p);

  p += 2;

  absl::numbers_internal::PutTwoDigits(static_cast<uint32_t>(usecs % 100), p);

  p += 2;

  *p++ = ' ';

  PutLeadingWhitespace(tid, p);

  p = absl::numbers_internal::FastIntToBuffer(tid, p);

  *p++ = ' ';

  const size_t bytes_formatted = static_cast<size_t>(p - buf.data());

  buf.remove_prefix(bytes_formatted);

  return bytes_formatted;

}

size_t FormatLineNumber(int line, absl::Span<char>& buf) {

  constexpr size_t kLineFieldMaxLen =

      sizeof(":] ") + (1 + std::numeric_limits<int>::digits10 + 1) - sizeof("");

  if (ABSL_PREDICT_FALSE(buf.size() < kLineFieldMaxLen)) {

    // As above, we don't bother trying to truncate this if the buffer is too

    // short and it should never happen.

    buf.remove_suffix(buf.size());

    return 0;

  }

  char* p = buf.data();

  *p++ = ':';

  p = absl::numbers_internal::FastIntToBuffer(line, p);

  *p++ = ']';

  *p++ = ' ';

  const size_t bytes_formatted = static_cast<size_t>(p - buf.data());

  buf.remove_prefix(bytes_formatted);

  return bytes_formatted;

}

}  // namespace

std::string FormatLogMessage(absl::LogSeverity severity,

                             absl::CivilSecond civil_second,

                             absl::Duration subsecond, log_internal::Tid tid,

                             absl::string_view basename, int line,

                             PrefixFormat format, absl::string_view message) {

  return absl::StrFormat(

      "%c%02d%02d %02d:%02d:%02d.%06d %7d %s:%d] %s%s",

      absl::LogSeverityName(severity)[0], civil_second.month(),

      civil_second.day(), civil_second.hour(), civil_second.minute(),

      civil_second.second(), absl::ToInt64Microseconds(subsecond), tid,

      basename, line, format == PrefixFormat::kRaw ? "RAW: " : "", message);

}

// This method is fairly hot, and the library always passes a huge `buf`, so we

// save some bounds-checking cycles by not trying to do precise truncation.

// Truncating at a field boundary is probably a better UX anyway.

//

// The prefix is written in three parts, each of which does a single

// bounds-check and truncation:

// 1. severity, timestamp, and thread ID

// 2. filename

// 3. line number and bracket

size_t FormatLogPrefix(absl::LogSeverity severity, absl::Time timestamp,

                       log_internal::Tid tid, absl::string_view basename,

                       int line, PrefixFormat format, absl::Span<char>& buf) {

  auto prefix_size = FormatBoundedFields(severity, timestamp, tid, buf);

  prefix_size += log_internal::AppendTruncated(basename, buf);

  prefix_size += FormatLineNumber(line, buf);

  if (format == PrefixFormat::kRaw)

    prefix_size += log_internal::AppendTruncated("RAW: ", buf);

  return prefix_size;

}

}  // namespace log_internal

ABSL_NAMESPACE_END

}  // namespace absl