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// 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.
//
// -----------------------------------------------------------------------------
// File: log/log_entry.h
// -----------------------------------------------------------------------------
//
// This header declares `class absl::LogEntry`, which represents a log record as
// passed to `LogSink::Send`. Data returned by pointer or by reference or by
// `absl::string_view` must be copied if they are needed after the lifetime of
// the `absl::LogEntry`.
#ifndef ABSL_LOG_LOG_ENTRY_H_
#define ABSL_LOG_LOG_ENTRY_H_
#include <cstddef>
#include <string>
#include "absl/base/config.h"
#include "absl/base/log_severity.h"
#include "absl/log/internal/config.h"
#include "absl/strings/string_view.h"
#include "absl/time/time.h"
#include "absl/types/span.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace log_internal {
// Test only friend.
class LogEntryTestPeer;
class LogMessage;
} // namespace log_internal
// LogEntry
//
// Represents a single entry in a log, i.e., one log message.
//
// LogEntry is copyable and thread-compatible.
class LogEntry final {
public:
using tid_t = log_internal::Tid;
// For non-verbose log entries, `verbosity()` returns `kNoVerbosityLevel`.
static constexpr int kNoVerbosityLevel = -1;
static constexpr int kNoVerboseLevel = -1; // TO BE removed
LogEntry(const LogEntry&) = default;
LogEntry& operator=(const LogEntry&) = default;
// Source file and line where the log message occurred.
// Take special care not to dereference the pointers returned by
// source_filename() and source_basename() after the lifetime of the
// `LogEntry`. This will usually work, because these are usually backed by a
// statically allocated char array obtained from the `__FILE__` macro, but
// it is nevertheless incorrect and will be broken by statements like
// `LOG(INFO).AtLocation(...)` (see above). If you need the data later, you
// must copy it.
absl::string_view source_filename() const { return full_filename_; }
absl::string_view source_basename() const { return base_filename_; }
int source_line() const { return line_; }
// LogEntry::prefix()
//
// True unless cleared by LOG(...).NoPrefix(), which indicates suppression of
// the line prefix containing metadata like file, line, timestamp, etc.
bool prefix() const { return prefix_; }
// LogEntry::log_severity()
//
// Returns this LogEntry's severity.
absl::LogSeverity log_severity() const { return severity_; }
// LogEntry::verbosity()
//
// Returns this LogEntry's verbosity, or kNoVerbosityLevel for a non-verbose
// LogEntry.
int verbosity() const { return verbose_level_; }
// LogEntry::timestamp()
//
// Returns the time at which this LogEntry was written.
absl::Time timestamp() const { return timestamp_; }
// LogEntry::tid()
//
// Returns the id of the thread that wrote this LogEntry.
tid_t tid() const { return tid_; }
// Text-formatted version of the log message. An underlying buffer holds:
//
// * A prefix formed by formatting metadata (timestamp, filename, line number,
// etc.)
// * The streamed data
// * A newline
// * A nul terminator
//
// These methods give access to the most commonly-used substrings of the
// buffer's contents. Other combinations can be obtained with substring
// arithmetic.
absl::string_view text_message_with_prefix_and_newline() const {
return absl::string_view(
text_message_with_prefix_and_newline_and_nul_.data(),
text_message_with_prefix_and_newline_and_nul_.size() - 1);
}
absl::string_view text_message_with_prefix() const {
return absl::string_view(
text_message_with_prefix_and_newline_and_nul_.data(),
text_message_with_prefix_and_newline_and_nul_.size() - 2);
}
absl::string_view text_message_with_newline() const {
return absl::string_view(
text_message_with_prefix_and_newline_and_nul_.data() + prefix_len_,
text_message_with_prefix_and_newline_and_nul_.size() - prefix_len_ - 1);
}
absl::string_view text_message() const {
return absl::string_view(
text_message_with_prefix_and_newline_and_nul_.data() + prefix_len_,
text_message_with_prefix_and_newline_and_nul_.size() - prefix_len_ - 2);
}
const char* text_message_with_prefix_and_newline_c_str() const {
return text_message_with_prefix_and_newline_and_nul_.data();
}
// LogEntry::stacktrace()
//
// Optional stacktrace, e.g., for `FATAL` logs.
absl::string_view stacktrace() const { return stacktrace_; }
private:
LogEntry() = default;
absl::string_view full_filename_;
absl::string_view base_filename_;
int line_;
bool prefix_;
absl::LogSeverity severity_;
int verbose_level_; // >=0 for `VLOG`, etc.; otherwise `kNoVerbosityLevel`.
absl::Time timestamp_;
tid_t tid_;
absl::Span<const char> text_message_with_prefix_and_newline_and_nul_;
size_t prefix_len_;
std::string stacktrace_;
friend class log_internal::LogEntryTestPeer;
friend class log_internal::LogMessage;
};
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_LOG_LOG_ENTRY_H_
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