Release the Abseil Logging library

PiperOrigin-RevId: 470080638
Change-Id: I8d9ddfabc7704c383ed5a73abf0411f4c58a4bf7

1 files changed, 189 insertions, 0 deletions

diff --git a/absl/log/internal/log_format.cc b/absl/log/internal/log_format.cc
new file mode 100644
index 00000000..b10a656b
--- /dev/null
+++ b/absl/log/internal/log_format.cc
@@ -0,0 +1,189 @@
+//
+// 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/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 {
+
+// 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(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(ci.cs.month(), p);
+  p += 2;
+  absl::numbers_internal::PutTwoDigits(ci.cs.day(), p);
+  p += 2;
+  *p++ = ' ';
+  absl::numbers_internal::PutTwoDigits(ci.cs.hour(), p);
+  p += 2;
+  *p++ = ':';
+  absl::numbers_internal::PutTwoDigits(ci.cs.minute(), p);
+  p += 2;
+  *p++ = ':';
+  absl::numbers_internal::PutTwoDigits(ci.cs.second(), p);
+  p += 2;
+  *p++ = '.';
+  const int64_t usecs = absl::ToInt64Microseconds(ci.subsecond);
+  absl::numbers_internal::PutTwoDigits(usecs / 10000, p);
+  p += 2;
+  absl::numbers_internal::PutTwoDigits(usecs / 100 % 100, p);
+  p += 2;
+  absl::numbers_internal::PutTwoDigits(usecs % 100, p);
+  p += 2;
+  *p++ = ' ';
+  constexpr bool unsigned_tid_t = !std::is_signed<log_internal::Tid>::value;
+  if ((unsigned_tid_t || tid >= 0) && tid < 10) *p++ = ' ';
+  if ((unsigned_tid_t || tid > -10) && tid < 100) *p++ = ' ';
+  if ((unsigned_tid_t || tid > -100) && tid < 1000) *p++ = ' ';
+  if ((unsigned_tid_t || tid > -1000) && tid < 10000) *p++ = ' ';
+  if ((unsigned_tid_t || tid > -10000) && tid < 100000) *p++ = ' ';
+  if ((unsigned_tid_t || tid > -100000) && tid < 1000000) *p++ = ' ';
+  p = absl::numbers_internal::FastIntToBuffer(tid, p);
+  *p++ = ' ';
+  const size_t bytes_formatted = p - buf.data();
+  buf.remove_prefix(bytes_formatted);
+  return bytes_formatted;
+}
+
+// Copies into `dst` as many bytes of `src` as will fit, then advances `dst`
+// past the copied bytes and returns the number of bytes written.
+size_t AppendTruncated(absl::string_view src, absl::Span<char>& dst) {
+  if (src.size() > dst.size()) src = src.substr(0, dst.size());
+  memcpy(dst.data(), src.data(), src.size());
+  dst.remove_prefix(src.size());
+  return src.size();
+}
+
+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 = 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,
+                             absl::string_view message) {
+  return absl::StrFormat(
+      "%c%02d%02d %02d:%02d:%02d.%06d %7d %s:%d] %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, 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, absl::Span<char>& buf) {
+  auto prefix_size = FormatBoundedFields(severity, timestamp, tid, buf);
+  prefix_size += AppendTruncated(basename, buf);
+  prefix_size += FormatLineNumber(line, buf);
+  return prefix_size;
+}
+
+}  // namespace log_internal
+ABSL_NAMESPACE_END
+}  // namespace absl