Squashed 'third_party/glog/' content from commit 9ef754a3023

git-subtree-dir: third_party/glog
git-subtree-split: 9ef754a3023e6fd10f20fe53dfca96dd898182e3

1 files changed, 2344 insertions, 0 deletions

diff --git a/src/logging.cc b/src/logging.cc
new file mode 100644
index 000000000000..ddcf91007358
--- /dev/null
+++ b/src/logging.cc
@@ -0,0 +1,2344 @@
+// Copyright (c) 1999, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#define _GNU_SOURCE 1 // needed for O_NOFOLLOW and pread()/pwrite()
+
+#include "utilities.h"
+
+#include <algorithm>
+#include <assert.h>
+#include <iomanip>
+#include <string>
+#ifdef HAVE_UNISTD_H
+# include <unistd.h>  // For _exit.
+#endif
+#include <climits>
+#include <sys/types.h>
+#include <sys/stat.h>
+#ifdef HAVE_SYS_UTSNAME_H
+# include <sys/utsname.h>  // For uname.
+#endif
+#include <time.h>
+#include <fcntl.h>
+#include <cstdio>
+#include <iostream>
+#include <stdarg.h>
+#include <stdlib.h>
+#ifdef HAVE_PWD_H
+# include <pwd.h>
+#endif
+#ifdef HAVE_SYSLOG_H
+# include <syslog.h>
+#endif
+#include <vector>
+#include <errno.h>                   // for errno
+#include <sstream>
+#ifdef OS_WINDOWS
+#include "windows/dirent.h"
+#else
+#include <dirent.h> // for automatic removal of old logs
+#endif
+#include "base/commandlineflags.h"        // to get the program name
+#include "glog/logging.h"
+#include "glog/raw_logging.h"
+#include "base/googleinit.h"
+
+#ifdef HAVE_STACKTRACE
+# include "stacktrace.h"
+#endif
+
+using std::string;
+using std::vector;
+using std::setw;
+using std::setfill;
+using std::hex;
+using std::dec;
+using std::min;
+using std::ostream;
+using std::ostringstream;
+
+using std::FILE;
+using std::fwrite;
+using std::fclose;
+using std::fflush;
+using std::fprintf;
+using std::perror;
+
+#ifdef __QNX__
+using std::fdopen;
+#endif
+
+#ifdef _WIN32
+#define fdopen _fdopen
+#endif
+
+// There is no thread annotation support.
+#define EXCLUSIVE_LOCKS_REQUIRED(mu)
+
+static bool BoolFromEnv(const char *varname, bool defval) {
+  const char* const valstr = getenv(varname);
+  if (!valstr) {
+    return defval;
+  }
+  return memchr("tTyY1\0", valstr[0], 6) != NULL;
+}
+
+GLOG_DEFINE_bool(timestamp_in_logfile_name,
+                 BoolFromEnv("GOOGLE_TIMESTAMP_IN_LOGFILE_NAME", true),
+                 "put a timestamp at the end of the log file name");
+GLOG_DEFINE_bool(logtostderr, BoolFromEnv("GOOGLE_LOGTOSTDERR", false),
+                 "log messages go to stderr instead of logfiles");
+GLOG_DEFINE_bool(alsologtostderr, BoolFromEnv("GOOGLE_ALSOLOGTOSTDERR", false),
+                 "log messages go to stderr in addition to logfiles");
+GLOG_DEFINE_bool(colorlogtostderr, false,
+                 "color messages logged to stderr (if supported by terminal)");
+#ifdef OS_LINUX
+GLOG_DEFINE_bool(drop_log_memory, true, "Drop in-memory buffers of log contents. "
+                 "Logs can grow very quickly and they are rarely read before they "
+                 "need to be evicted from memory. Instead, drop them from memory "
+                 "as soon as they are flushed to disk.");
+#endif
+
+// By default, errors (including fatal errors) get logged to stderr as
+// well as the file.
+//
+// The default is ERROR instead of FATAL so that users can see problems
+// when they run a program without having to look in another file.
+DEFINE_int32(stderrthreshold,
+             GOOGLE_NAMESPACE::GLOG_ERROR,
+             "log messages at or above this level are copied to stderr in "
+             "addition to logfiles.  This flag obsoletes --alsologtostderr.");
+
+GLOG_DEFINE_string(alsologtoemail, "",
+                   "log messages go to these email addresses "
+                   "in addition to logfiles");
+GLOG_DEFINE_bool(log_prefix, true,
+                 "Prepend the log prefix to the start of each log line");
+GLOG_DEFINE_int32(minloglevel, 0, "Messages logged at a lower level than this don't "
+                  "actually get logged anywhere");
+GLOG_DEFINE_int32(logbuflevel, 0,
+                  "Buffer log messages logged at this level or lower"
+                  " (-1 means don't buffer; 0 means buffer INFO only;"
+                  " ...)");
+GLOG_DEFINE_int32(logbufsecs, 30,
+                  "Buffer log messages for at most this many seconds");
+GLOG_DEFINE_int32(logemaillevel, 999,
+                  "Email log messages logged at this level or higher"
+                  " (0 means email all; 3 means email FATAL only;"
+                  " ...)");
+GLOG_DEFINE_string(logmailer, "/bin/mail",
+                   "Mailer used to send logging email");
+
+// Compute the default value for --log_dir
+static const char* DefaultLogDir() {
+  const char* env;
+  env = getenv("GOOGLE_LOG_DIR");
+  if (env != NULL && env[0] != '\0') {
+    return env;
+  }
+  env = getenv("TEST_TMPDIR");
+  if (env != NULL && env[0] != '\0') {
+    return env;
+  }
+  return "";
+}
+
+GLOG_DEFINE_int32(logfile_mode, 0664, "Log file mode/permissions.");
+
+GLOG_DEFINE_string(log_dir, DefaultLogDir(),
+                   "If specified, logfiles are written into this directory instead "
+                   "of the default logging directory.");
+GLOG_DEFINE_string(log_link, "", "Put additional links to the log "
+                   "files in this directory");
+
+GLOG_DEFINE_int32(max_log_size, 1800,
+                  "approx. maximum log file size (in MB). A value of 0 will "
+                  "be silently overridden to 1.");
+
+GLOG_DEFINE_bool(stop_logging_if_full_disk, false,
+                 "Stop attempting to log to disk if the disk is full.");
+
+GLOG_DEFINE_string(log_backtrace_at, "",
+                   "Emit a backtrace when logging at file:linenum.");
+
+// TODO(hamaji): consider windows
+#define PATH_SEPARATOR '/'
+
+#ifndef HAVE_PREAD
+#if defined(OS_WINDOWS)
+#include <basetsd.h>
+#define ssize_t SSIZE_T
+#endif
+static ssize_t pread(int fd, void* buf, size_t count, off_t offset) {
+  off_t orig_offset = lseek(fd, 0, SEEK_CUR);
+  if (orig_offset == (off_t)-1)
+    return -1;
+  if (lseek(fd, offset, SEEK_CUR) == (off_t)-1)
+    return -1;
+  ssize_t len = read(fd, buf, count);
+  if (len < 0)
+    return len;
+  if (lseek(fd, orig_offset, SEEK_SET) == (off_t)-1)
+    return -1;
+  return len;
+}
+#endif  // !HAVE_PREAD
+
+#ifndef HAVE_PWRITE
+static ssize_t pwrite(int fd, void* buf, size_t count, off_t offset) {
+  off_t orig_offset = lseek(fd, 0, SEEK_CUR);
+  if (orig_offset == (off_t)-1)
+    return -1;
+  if (lseek(fd, offset, SEEK_CUR) == (off_t)-1)
+    return -1;
+  ssize_t len = write(fd, buf, count);
+  if (len < 0)
+    return len;
+  if (lseek(fd, orig_offset, SEEK_SET) == (off_t)-1)
+    return -1;
+  return len;
+}
+#endif  // !HAVE_PWRITE
+
+static void GetHostName(string* hostname) {
+#if defined(HAVE_SYS_UTSNAME_H)
+  struct utsname buf;
+  if (0 != uname(&buf)) {
+    // ensure null termination on failure
+    *buf.nodename = '\0';
+  }
+  *hostname = buf.nodename;
+#elif defined(OS_WINDOWS)
+  char buf[MAX_COMPUTERNAME_LENGTH + 1];
+  DWORD len = MAX_COMPUTERNAME_LENGTH + 1;
+  if (GetComputerNameA(buf, &len)) {
+    *hostname = buf;
+  } else {
+    hostname->clear();
+  }
+#else
+# warning There is no way to retrieve the host name.
+  *hostname = "(unknown)";
+#endif
+}
+
+// Returns true iff terminal supports using colors in output.
+static bool TerminalSupportsColor() {
+  bool term_supports_color = false;
+#ifdef OS_WINDOWS
+  // on Windows TERM variable is usually not set, but the console does
+  // support colors.
+  term_supports_color = true;
+#else
+  // On non-Windows platforms, we rely on the TERM variable.
+  const char* const term = getenv("TERM");
+  if (term != NULL && term[0] != '\0') {
+    term_supports_color =
+      !strcmp(term, "xterm") ||
+      !strcmp(term, "xterm-color") ||
+      !strcmp(term, "xterm-256color") ||
+      !strcmp(term, "screen-256color") ||
+      !strcmp(term, "konsole") ||
+      !strcmp(term, "konsole-16color") ||
+      !strcmp(term, "konsole-256color") ||
+      !strcmp(term, "screen") ||
+      !strcmp(term, "linux") ||
+      !strcmp(term, "cygwin");
+  }
+#endif
+  return term_supports_color;
+}
+
+_START_GOOGLE_NAMESPACE_
+
+enum GLogColor {
+  COLOR_DEFAULT,
+  COLOR_RED,
+  COLOR_GREEN,
+  COLOR_YELLOW
+};
+
+static GLogColor SeverityToColor(LogSeverity severity) {
+  assert(severity >= 0 && severity < NUM_SEVERITIES);
+  GLogColor color = COLOR_DEFAULT;
+  switch (severity) {
+  case GLOG_INFO:
+    color = COLOR_DEFAULT;
+    break;
+  case GLOG_WARNING:
+    color = COLOR_YELLOW;
+    break;
+  case GLOG_ERROR:
+  case GLOG_FATAL:
+    color = COLOR_RED;
+    break;
+  default:
+    // should never get here.
+    assert(false);
+  }
+  return color;
+}
+
+#ifdef OS_WINDOWS
+
+// Returns the character attribute for the given color.
+static WORD GetColorAttribute(GLogColor color) {
+  switch (color) {
+    case COLOR_RED:    return FOREGROUND_RED;
+    case COLOR_GREEN:  return FOREGROUND_GREEN;
+    case COLOR_YELLOW: return FOREGROUND_RED | FOREGROUND_GREEN;
+    default:           return 0;
+  }
+}
+
+#else
+
+// Returns the ANSI color code for the given color.
+static const char* GetAnsiColorCode(GLogColor color) {
+  switch (color) {
+  case COLOR_RED:     return "1";
+  case COLOR_GREEN:   return "2";
+  case COLOR_YELLOW:  return "3";
+  case COLOR_DEFAULT:  return "";
+  };
+  return NULL; // stop warning about return type.
+}
+
+#endif  // OS_WINDOWS
+
+// Safely get max_log_size, overriding to 1 if it somehow gets defined as 0
+static int32 MaxLogSize() {
+  return (FLAGS_max_log_size > 0 ? FLAGS_max_log_size : 1);
+}
+
+// An arbitrary limit on the length of a single log message.  This
+// is so that streaming can be done more efficiently.
+const size_t LogMessage::kMaxLogMessageLen = 30000;
+
+struct LogMessage::LogMessageData  {
+  LogMessageData();
+
+  int preserved_errno_;      // preserved errno
+  // Buffer space; contains complete message text.
+  char message_text_[LogMessage::kMaxLogMessageLen+1];
+  LogStream stream_;
+  char severity_;      // What level is this LogMessage logged at?
+  int line_;                 // line number where logging call is.
+  void (LogMessage::*send_method_)();  // Call this in destructor to send
+  union {  // At most one of these is used: union to keep the size low.
+    LogSink* sink_;             // NULL or sink to send message to
+    std::vector<std::string>* outvec_; // NULL or vector to push message onto
+    std::string* message_;             // NULL or string to write message into
+  };
+  time_t timestamp_;            // Time of creation of LogMessage
+  struct ::tm tm_time_;         // Time of creation of LogMessage
+  int32 usecs_;                   // Time of creation of LogMessage - microseconds part
+  size_t num_prefix_chars_;     // # of chars of prefix in this message
+  size_t num_chars_to_log_;     // # of chars of msg to send to log
+  size_t num_chars_to_syslog_;  // # of chars of msg to send to syslog
+  const char* basename_;        // basename of file that called LOG
+  const char* fullname_;        // fullname of file that called LOG
+  bool has_been_flushed_;       // false => data has not been flushed
+  bool first_fatal_;            // true => this was first fatal msg
+
+ private:
+  LogMessageData(const LogMessageData&);
+  void operator=(const LogMessageData&);
+};
+
+// A mutex that allows only one thread to log at a time, to keep things from
+// getting jumbled.  Some other very uncommon logging operations (like
+// changing the destination file for log messages of a given severity) also
+// lock this mutex.  Please be sure that anybody who might possibly need to
+// lock it does so.
+static Mutex log_mutex;
+
+// Number of messages sent at each severity.  Under log_mutex.
+int64 LogMessage::num_messages_[NUM_SEVERITIES] = {0, 0, 0, 0};
+
+// Globally disable log writing (if disk is full)
+static bool stop_writing = false;
+
+const char*const LogSeverityNames[NUM_SEVERITIES] = {
+  "INFO", "WARNING", "ERROR", "FATAL"
+};
+
+// Has the user called SetExitOnDFatal(true)?
+static bool exit_on_dfatal = true;
+
+const char* GetLogSeverityName(LogSeverity severity) {
+  return LogSeverityNames[severity];
+}
+
+static bool SendEmailInternal(const char*dest, const char *subject,
+                              const char*body, bool use_logging);
+
+base::Logger::~Logger() {
+}
+
+namespace {
+
+// Encapsulates all file-system related state
+class LogFileObject : public base::Logger {
+ public:
+  LogFileObject(LogSeverity severity, const char* base_filename);
+  ~LogFileObject();
+
+  virtual void Write(bool force_flush, // Should we force a flush here?
+                     time_t timestamp,  // Timestamp for this entry
+                     const char* message,
+                     int message_len);
+
+  // Configuration options
+  void SetBasename(const char* basename);
+  void SetExtension(const char* ext);
+  void SetSymlinkBasename(const char* symlink_basename);
+
+  // Normal flushing routine
+  virtual void Flush();
+
+  // It is the actual file length for the system loggers,
+  // i.e., INFO, ERROR, etc.
+  virtual uint32 LogSize() {
+    MutexLock l(&lock_);
+    return file_length_;
+  }
+
+  // Internal flush routine.  Exposed so that FlushLogFilesUnsafe()
+  // can avoid grabbing a lock.  Usually Flush() calls it after
+  // acquiring lock_.
+  void FlushUnlocked();
+
+ private:
+  static const uint32 kRolloverAttemptFrequency = 0x20;
+
+  Mutex lock_;
+  bool base_filename_selected_;
+  string base_filename_;
+  string symlink_basename_;
+  string filename_extension_;     // option users can specify (eg to add port#)
+  FILE* file_;
+  LogSeverity severity_;
+  uint32 bytes_since_flush_;
+  uint32 dropped_mem_length_;
+  uint32 file_length_;
+  unsigned int rollover_attempt_;
+  int64 next_flush_time_;         // cycle count at which to flush log
+
+  // Actually create a logfile using the value of base_filename_ and the
+  // optional argument time_pid_string
+  // REQUIRES: lock_ is held
+  bool CreateLogfile(const string& time_pid_string);
+};
+
+}  // namespace
+
+class LogDestination {
+ public:
+  friend class LogMessage;
+  friend void ReprintFatalMessage();
+  friend base::Logger* base::GetLogger(LogSeverity);
+  friend void base::SetLogger(LogSeverity, base::Logger*);
+
+  // These methods are just forwarded to by their global versions.
+  static void SetLogDestination(LogSeverity severity,
+				const char* base_filename);
+  static void SetLogSymlink(LogSeverity severity,
+                            const char* symlink_basename);
+  static void AddLogSink(LogSink *destination);
+  static void RemoveLogSink(LogSink *destination);
+  static void SetLogFilenameExtension(const char* filename_extension);
+  static void SetStderrLogging(LogSeverity min_severity);
+  static void SetEmailLogging(LogSeverity min_severity, const char* addresses);
+  static void LogToStderr();
+  // Flush all log files that are at least at the given severity level
+  static void FlushLogFiles(int min_severity);
+  static void FlushLogFilesUnsafe(int min_severity);
+
+  // we set the maximum size of our packet to be 1400, the logic being
+  // to prevent fragmentation.
+  // Really this number is arbitrary.
+  static const int kNetworkBytes = 1400;
+
+  static const string& hostname();
+  static const bool& terminal_supports_color() {
+    return terminal_supports_color_;
+  }
+
+  static void DeleteLogDestinations();
+
+ private:
+  LogDestination(LogSeverity severity, const char* base_filename);
+  ~LogDestination();
+
+  // Take a log message of a particular severity and log it to stderr
+  // iff it's of a high enough severity to deserve it.
+  static void MaybeLogToStderr(LogSeverity severity, const char* message,
+			       size_t len);
+
+  // Take a log message of a particular severity and log it to email
+  // iff it's of a high enough severity to deserve it.
+  static void MaybeLogToEmail(LogSeverity severity, const char* message,
+			      size_t len);
+  // Take a log message of a particular severity and log it to a file
+  // iff the base filename is not "" (which means "don't log to me")
+  static void MaybeLogToLogfile(LogSeverity severity,
+                                time_t timestamp,
+				const char* message, size_t len);
+  // Take a log message of a particular severity and log it to the file
+  // for that severity and also for all files with severity less than
+  // this severity.
+  static void LogToAllLogfiles(LogSeverity severity,
+                               time_t timestamp,
+                               const char* message, size_t len);
+
+  // Send logging info to all registered sinks.
+  static void LogToSinks(LogSeverity severity,
+                         const char *full_filename,
+                         const char *base_filename,
+                         int line,
+                         const struct ::tm* tm_time,
+                         const char* message,
+                         size_t message_len,
+                         int32 usecs);
+
+  // Wait for all registered sinks via WaitTillSent
+  // including the optional one in "data".
+  static void WaitForSinks(LogMessage::LogMessageData* data);
+
+  static LogDestination* log_destination(LogSeverity severity);
+
+  LogFileObject fileobject_;
+  base::Logger* logger_;      // Either &fileobject_, or wrapper around it
+
+  static LogDestination* log_destinations_[NUM_SEVERITIES];
+  static LogSeverity email_logging_severity_;
+  static string addresses_;
+  static string hostname_;
+  static bool terminal_supports_color_;
+
+  // arbitrary global logging destinations.
+  static vector<LogSink*>* sinks_;
+
+  // Protects the vector sinks_,
+  // but not the LogSink objects its elements reference.
+  static Mutex sink_mutex_;
+
+  // Disallow
+  LogDestination(const LogDestination&);
+  LogDestination& operator=(const LogDestination&);
+};
+
+// Errors do not get logged to email by default.
+LogSeverity LogDestination::email_logging_severity_ = 99999;
+
+string LogDestination::addresses_;
+string LogDestination::hostname_;
+
+vector<LogSink*>* LogDestination::sinks_ = NULL;
+Mutex LogDestination::sink_mutex_;
+bool LogDestination::terminal_supports_color_ = TerminalSupportsColor();
+
+/* static */
+const string& LogDestination::hostname() {
+  if (hostname_.empty()) {
+    GetHostName(&hostname_);
+    if (hostname_.empty()) {
+      hostname_ = "(unknown)";
+    }
+  }
+  return hostname_;
+}
+
+LogDestination::LogDestination(LogSeverity severity,
+                               const char* base_filename)
+  : fileobject_(severity, base_filename),
+    logger_(&fileobject_) {
+}
+
+LogDestination::~LogDestination() {
+  if (logger_ && logger_ != &fileobject_) {
+    // Delete user-specified logger set via SetLogger().
+    delete logger_;
+  }
+}
+
+inline void LogDestination::FlushLogFilesUnsafe(int min_severity) {
+  // assume we have the log_mutex or we simply don't care
+  // about it
+  for (int i = min_severity; i < NUM_SEVERITIES; i++) {
+    LogDestination* log = log_destinations_[i];
+    if (log != NULL) {
+      // Flush the base fileobject_ logger directly instead of going
+      // through any wrappers to reduce chance of deadlock.
+      log->fileobject_.FlushUnlocked();
+    }
+  }
+}
+
+inline void LogDestination::FlushLogFiles(int min_severity) {
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&log_mutex);
+  for (int i = min_severity; i < NUM_SEVERITIES; i++) {
+    LogDestination* log = log_destination(i);
+    if (log != NULL) {
+      log->logger_->Flush();
+    }
+  }
+}
+
+inline void LogDestination::SetLogDestination(LogSeverity severity,
+					      const char* base_filename) {
+  assert(severity >= 0 && severity < NUM_SEVERITIES);
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&log_mutex);
+  log_destination(severity)->fileobject_.SetBasename(base_filename);
+}
+
+inline void LogDestination::SetLogSymlink(LogSeverity severity,
+                                          const char* symlink_basename) {
+  CHECK_GE(severity, 0);
+  CHECK_LT(severity, NUM_SEVERITIES);
+  MutexLock l(&log_mutex);
+  log_destination(severity)->fileobject_.SetSymlinkBasename(symlink_basename);
+}
+
+inline void LogDestination::AddLogSink(LogSink *destination) {
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&sink_mutex_);
+  if (!sinks_)  sinks_ = new vector<LogSink*>;
+  sinks_->push_back(destination);
+}
+
+inline void LogDestination::RemoveLogSink(LogSink *destination) {
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&sink_mutex_);
+  // This doesn't keep the sinks in order, but who cares?
+  if (sinks_) {
+    for (int i = sinks_->size() - 1; i >= 0; i--) {
+      if ((*sinks_)[i] == destination) {
+        (*sinks_)[i] = (*sinks_)[sinks_->size() - 1];
+        sinks_->pop_back();
+        break;
+      }
+    }
+  }
+}
+
+inline void LogDestination::SetLogFilenameExtension(const char* ext) {
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&log_mutex);
+  for ( int severity = 0; severity < NUM_SEVERITIES; ++severity ) {
+    log_destination(severity)->fileobject_.SetExtension(ext);
+  }
+}
+
+inline void LogDestination::SetStderrLogging(LogSeverity min_severity) {
+  assert(min_severity >= 0 && min_severity < NUM_SEVERITIES);
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&log_mutex);
+  FLAGS_stderrthreshold = min_severity;
+}
+
+inline void LogDestination::LogToStderr() {
+  // *Don't* put this stuff in a mutex lock, since SetStderrLogging &
+  // SetLogDestination already do the locking!
+  SetStderrLogging(0);            // thus everything is "also" logged to stderr
+  for ( int i = 0; i < NUM_SEVERITIES; ++i ) {
+    SetLogDestination(i, "");     // "" turns off logging to a logfile
+  }
+}
+
+inline void LogDestination::SetEmailLogging(LogSeverity min_severity,
+					    const char* addresses) {
+  assert(min_severity >= 0 && min_severity < NUM_SEVERITIES);
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // all this stuff.
+  MutexLock l(&log_mutex);
+  LogDestination::email_logging_severity_ = min_severity;
+  LogDestination::addresses_ = addresses;
+}
+
+static void ColoredWriteToStderr(LogSeverity severity,
+                                 const char* message, size_t len) {
+  const GLogColor color =
+      (LogDestination::terminal_supports_color() && FLAGS_colorlogtostderr) ?
+      SeverityToColor(severity) : COLOR_DEFAULT;
+
+  // Avoid using cerr from this module since we may get called during
+  // exit code, and cerr may be partially or fully destroyed by then.
+  if (COLOR_DEFAULT == color) {
+    fwrite(message, len, 1, stderr);
+    return;
+  }
+#ifdef OS_WINDOWS
+  const HANDLE stderr_handle = GetStdHandle(STD_ERROR_HANDLE);
+
+  // Gets the current text color.
+  CONSOLE_SCREEN_BUFFER_INFO buffer_info;
+  GetConsoleScreenBufferInfo(stderr_handle, &buffer_info);
+  const WORD old_color_attrs = buffer_info.wAttributes;
+
+  // We need to flush the stream buffers into the console before each
+  // SetConsoleTextAttribute call lest it affect the text that is already
+  // printed but has not yet reached the console.
+  fflush(stderr);
+  SetConsoleTextAttribute(stderr_handle,
+                          GetColorAttribute(color) | FOREGROUND_INTENSITY);
+  fwrite(message, len, 1, stderr);
+  fflush(stderr);
+  // Restores the text color.
+  SetConsoleTextAttribute(stderr_handle, old_color_attrs);
+#else
+  fprintf(stderr, "\033[0;3%sm", GetAnsiColorCode(color));
+  fwrite(message, len, 1, stderr);
+  fprintf(stderr, "\033[m");  // Resets the terminal to default.
+#endif  // OS_WINDOWS
+}
+
+static void WriteToStderr(const char* message, size_t len) {
+  // Avoid using cerr from this module since we may get called during
+  // exit code, and cerr may be partially or fully destroyed by then.
+  fwrite(message, len, 1, stderr);
+}
+
+inline void LogDestination::MaybeLogToStderr(LogSeverity severity,
+					     const char* message, size_t len) {
+  if ((severity >= FLAGS_stderrthreshold) || FLAGS_alsologtostderr) {
+    ColoredWriteToStderr(severity, message, len);
+#ifdef OS_WINDOWS
+    // On Windows, also output to the debugger
+    ::OutputDebugStringA(string(message,len).c_str());
+#endif
+  }
+}
+
+
+inline void LogDestination::MaybeLogToEmail(LogSeverity severity,
+					    const char* message, size_t len) {
+  if (severity >= email_logging_severity_ ||
+      severity >= FLAGS_logemaillevel) {
+    string to(FLAGS_alsologtoemail);
+    if (!addresses_.empty()) {
+      if (!to.empty()) {
+        to += ",";
+      }
+      to += addresses_;
+    }
+    const string subject(string("[LOG] ") + LogSeverityNames[severity] + ": " +
+                         glog_internal_namespace_::ProgramInvocationShortName());
+    string body(hostname());
+    body += "\n\n";
+    body.append(message, len);
+
+    // should NOT use SendEmail().  The caller of this function holds the
+    // log_mutex and SendEmail() calls LOG/VLOG which will block trying to
+    // acquire the log_mutex object.  Use SendEmailInternal() and set
+    // use_logging to false.
+    SendEmailInternal(to.c_str(), subject.c_str(), body.c_str(), false);
+  }
+}
+
+
+inline void LogDestination::MaybeLogToLogfile(LogSeverity severity,
+                                              time_t timestamp,
+					      const char* message,
+					      size_t len) {
+  const bool should_flush = severity > FLAGS_logbuflevel;
+  LogDestination* destination = log_destination(severity);
+  destination->logger_->Write(should_flush, timestamp, message, len);
+}
+
+inline void LogDestination::LogToAllLogfiles(LogSeverity severity,
+                                             time_t timestamp,
+                                             const char* message,
+                                             size_t len) {
+
+  if ( FLAGS_logtostderr ) {           // global flag: never log to file
+    ColoredWriteToStderr(severity, message, len);
+  } else {
+    for (int i = severity; i >= 0; --i)
+      LogDestination::MaybeLogToLogfile(i, timestamp, message, len);
+  }
+}
+
+inline void LogDestination::LogToSinks(LogSeverity severity,
+                                       const char *full_filename,
+                                       const char *base_filename,
+                                       int line,
+                                       const struct ::tm* tm_time,
+                                       const char* message,
+                                       size_t message_len,
+                                       int32 usecs) {
+  ReaderMutexLock l(&sink_mutex_);
+  if (sinks_) {
+    for (int i = sinks_->size() - 1; i >= 0; i--) {
+      (*sinks_)[i]->send(severity, full_filename, base_filename,
+                         line, tm_time, message, message_len, usecs);
+    }
+  }
+}
+
+inline void LogDestination::WaitForSinks(LogMessage::LogMessageData* data) {
+  ReaderMutexLock l(&sink_mutex_);
+  if (sinks_) {
+    for (int i = sinks_->size() - 1; i >= 0; i--) {
+      (*sinks_)[i]->WaitTillSent();
+    }
+  }
+  const bool send_to_sink =
+      (data->send_method_ == &LogMessage::SendToSink) ||
+      (data->send_method_ == &LogMessage::SendToSinkAndLog);
+  if (send_to_sink && data->sink_ != NULL) {
+    data->sink_->WaitTillSent();
+  }
+}
+
+LogDestination* LogDestination::log_destinations_[NUM_SEVERITIES];
+
+inline LogDestination* LogDestination::log_destination(LogSeverity severity) {
+  assert(severity >=0 && severity < NUM_SEVERITIES);
+  if (!log_destinations_[severity]) {
+    log_destinations_[severity] = new LogDestination(severity, NULL);
+  }
+  return log_destinations_[severity];
+}
+
+void LogDestination::DeleteLogDestinations() {
+  for (int severity = 0; severity < NUM_SEVERITIES; ++severity) {
+    delete log_destinations_[severity];
+    log_destinations_[severity] = NULL;
+  }
+  MutexLock l(&sink_mutex_);
+  delete sinks_;
+  sinks_ = NULL;
+}
+
+namespace {
+
+bool IsGlogLog(const string& filename) {
+  // Check if filename matches the pattern of a glog file:
+  // "<program name>.<hostname>.<user name>.log...".
+  const int kKeywordCount = 4;
+  std::string keywords[kKeywordCount] = {
+    glog_internal_namespace_::ProgramInvocationShortName(),
+    LogDestination::hostname(),
+    MyUserName(),
+    "log"
+  };
+
+  int start_pos = 0;
+  for (int i = 0; i < kKeywordCount; i++) {
+    if (filename.find(keywords[i], start_pos) == filename.npos) {
+      return false;
+    }
+    start_pos += keywords[i].size() + 1;
+  }
+  return true;
+}
+
+bool LastModifiedOver(const string& filepath, int days) {
+  // Try to get the last modified time of this file.
+  struct stat file_stat;
+
+  if (stat(filepath.c_str(), &file_stat) == 0) {
+    // A day is 86400 seconds, so 7 days is 86400 * 7 = 604800 seconds.
+    time_t last_modified_time = file_stat.st_mtime;
+    time_t current_time = time(NULL);
+    return difftime(current_time, last_modified_time) > days * 86400;
+  }
+
+  // If failed to get file stat, don't return true!
+  return false;
+}
+
+vector<string> GetOverdueLogNames(string log_directory, int days) {
+  // The names of overdue logs.
+  vector<string> overdue_log_names;
+
+  // Try to get all files within log_directory.
+  DIR *dir;
+  struct dirent *ent;
+
+  char dir_delim = '/';
+#ifdef OS_WINDOWS
+  dir_delim = '\\';
+#endif
+
+  // If log_directory doesn't end with a slash, append a slash to it.
+  if (log_directory.at(log_directory.size() - 1) != dir_delim) {
+    log_directory += dir_delim;
+  }
+
+  if ((dir=opendir(log_directory.c_str()))) {
+    while ((ent=readdir(dir))) {
+      if (!strcmp(ent->d_name, ".") || !strcmp(ent->d_name, "..")) {
+        continue;
+      }
+      string filepath = log_directory + ent->d_name;
+      if (IsGlogLog(ent->d_name) && LastModifiedOver(filepath, days)) {
+        overdue_log_names.push_back(filepath);
+      }
+    }
+    closedir(dir);
+  }
+
+  return overdue_log_names;
+}
+
+// Is log_cleaner enabled?
+// This option can be enabled by calling google::EnableLogCleaner(days)
+bool log_cleaner_enabled_;
+int log_cleaner_overdue_days_ = 7;
+
+} // namespace
+
+
+namespace {
+
+LogFileObject::LogFileObject(LogSeverity severity,
+                             const char* base_filename)
+  : base_filename_selected_(base_filename != NULL),
+    base_filename_((base_filename != NULL) ? base_filename : ""),
+    symlink_basename_(glog_internal_namespace_::ProgramInvocationShortName()),
+    filename_extension_(),
+    file_(NULL),
+    severity_(severity),
+    bytes_since_flush_(0),
+    dropped_mem_length_(0),
+    file_length_(0),
+    rollover_attempt_(kRolloverAttemptFrequency-1),
+    next_flush_time_(0) {
+  assert(severity >= 0);
+  assert(severity < NUM_SEVERITIES);
+}
+
+LogFileObject::~LogFileObject() {
+  MutexLock l(&lock_);
+  if (file_ != NULL) {
+    fclose(file_);
+    file_ = NULL;
+  }
+}
+
+void LogFileObject::SetBasename(const char* basename) {
+  MutexLock l(&lock_);
+  base_filename_selected_ = true;
+  if (base_filename_ != basename) {
+    // Get rid of old log file since we are changing names
+    if (file_ != NULL) {
+      fclose(file_);
+      file_ = NULL;
+      rollover_attempt_ = kRolloverAttemptFrequency-1;
+    }
+    base_filename_ = basename;
+  }
+}
+
+void LogFileObject::SetExtension(const char* ext) {
+  MutexLock l(&lock_);
+  if (filename_extension_ != ext) {
+    // Get rid of old log file since we are changing names
+    if (file_ != NULL) {
+      fclose(file_);
+      file_ = NULL;
+      rollover_attempt_ = kRolloverAttemptFrequency-1;
+    }
+    filename_extension_ = ext;
+  }
+}
+
+void LogFileObject::SetSymlinkBasename(const char* symlink_basename) {
+  MutexLock l(&lock_);
+  symlink_basename_ = symlink_basename;
+}
+
+void LogFileObject::Flush() {
+  MutexLock l(&lock_);
+  FlushUnlocked();
+}
+
+void LogFileObject::FlushUnlocked(){
+  if (file_ != NULL) {
+    fflush(file_);
+    bytes_since_flush_ = 0;
+  }
+  // Figure out when we are due for another flush.
+  const int64 next = (FLAGS_logbufsecs
+                      * static_cast<int64>(1000000));  // in usec
+  next_flush_time_ = CycleClock_Now() + UsecToCycles(next);
+}
+
+bool LogFileObject::CreateLogfile(const string& time_pid_string) {
+  string string_filename = base_filename_+filename_extension_;
+  if (FLAGS_timestamp_in_logfile_name) {
+    string_filename += time_pid_string;
+  }
+  const char* filename = string_filename.c_str();
+  //only write to files, create if non-existant.
+  int flags = O_WRONLY | O_CREAT;
+  if (FLAGS_timestamp_in_logfile_name) {
+    //demand that the file is unique for our timestamp (fail if it exists).
+    flags = flags | O_EXCL;
+  }
+  int fd = open(filename, flags, FLAGS_logfile_mode);
+  if (fd == -1) return false;
+#ifdef HAVE_FCNTL
+  // Mark the file close-on-exec. We don't really care if this fails
+  fcntl(fd, F_SETFD, FD_CLOEXEC);
+
+  // Mark the file as exclusive write access to avoid two clients logging to the
+  // same file. This applies particularly when !FLAGS_timestamp_in_logfile_name
+  // (otherwise open would fail because the O_EXCL flag on similar filename).
+  // locks are released on unlock or close() automatically, only after log is
+  // released.
+  // This will work after a fork as it is not inherited (not stored in the fd).
+  // Lock will not be lost because the file is opened with exclusive lock (write)
+  // and we will never read from it inside the process.
+  // TODO windows implementation of this (as flock is not available on mingw).
+  static struct flock w_lock;
+
+  w_lock.l_type = F_WRLCK;
+  w_lock.l_start = 0;
+  w_lock.l_whence = SEEK_SET;
+  w_lock.l_len = 0;
+
+  int wlock_ret = fcntl(fd, F_SETLK, &w_lock);
+  if (wlock_ret == -1) {
+      close(fd); //as we are failing already, do not check errors here
+      return false;
+  }
+#endif
+
+  //fdopen in append mode so if the file exists it will fseek to the end
+  file_ = fdopen(fd, "a");  // Make a FILE*.
+  if (file_ == NULL) {  // Man, we're screwed!
+    close(fd);
+    if (FLAGS_timestamp_in_logfile_name) {
+      unlink(filename);  // Erase the half-baked evidence: an unusable log file, only if we just created it.
+    }
+    return false;
+  }
+#ifdef OS_WINDOWS
+  // https://github.com/golang/go/issues/27638 - make sure we seek to the end to append
+  // empirically replicated with wine over mingw build
+  if (!FLAGS_timestamp_in_logfile_name) {
+    if (fseek(file_, 0, SEEK_END) != 0) {
+      return false;
+    }
+  }
+#endif
+  // We try to create a symlink called <program_name>.<severity>,
+  // which is easier to use.  (Every time we create a new logfile,
+  // we destroy the old symlink and create a new one, so it always
+  // points to the latest logfile.)  If it fails, we're sad but it's
+  // no error.
+  if (!symlink_basename_.empty()) {
+    // take directory from filename
+    const char* slash = strrchr(filename, PATH_SEPARATOR);
+    const string linkname =
+      symlink_basename_ + '.' + LogSeverityNames[severity_];
+    string linkpath;
+    if ( slash ) linkpath = string(filename, slash-filename+1);  // get dirname
+    linkpath += linkname;
+    unlink(linkpath.c_str());                    // delete old one if it exists
+
+#if defined(OS_WINDOWS)
+    // TODO(hamaji): Create lnk file on Windows?
+#elif defined(HAVE_UNISTD_H)
+    // We must have unistd.h.
+    // Make the symlink be relative (in the same dir) so that if the
+    // entire log directory gets relocated the link is still valid.
+    const char *linkdest = slash ? (slash + 1) : filename;
+    if (symlink(linkdest, linkpath.c_str()) != 0) {
+      // silently ignore failures
+    }
+
+    // Make an additional link to the log file in a place specified by
+    // FLAGS_log_link, if indicated
+    if (!FLAGS_log_link.empty()) {
+      linkpath = FLAGS_log_link + "/" + linkname;
+      unlink(linkpath.c_str());                  // delete old one if it exists
+      if (symlink(filename, linkpath.c_str()) != 0) {
+        // silently ignore failures
+      }
+    }
+#endif
+  }
+
+  return true;  // Everything worked
+}
+
+void LogFileObject::Write(bool force_flush,
+                          time_t timestamp,
+                          const char* message,
+                          int message_len) {
+  MutexLock l(&lock_);
+
+  // We don't log if the base_name_ is "" (which means "don't write")
+  if (base_filename_selected_ && base_filename_.empty()) {
+    return;
+  }
+
+  if (static_cast<int>(file_length_ >> 20) >= MaxLogSize() ||
+      PidHasChanged()) {
+    if (file_ != NULL) fclose(file_);
+    file_ = NULL;
+    file_length_ = bytes_since_flush_ = dropped_mem_length_ = 0;
+    rollover_attempt_ = kRolloverAttemptFrequency-1;
+  }
+
+  // If there's no destination file, make one before outputting
+  if (file_ == NULL) {
+    // Try to rollover the log file every 32 log messages.  The only time
+    // this could matter would be when we have trouble creating the log
+    // file.  If that happens, we'll lose lots of log messages, of course!
+    if (++rollover_attempt_ != kRolloverAttemptFrequency) return;
+    rollover_attempt_ = 0;
+
+    struct ::tm tm_time;
+    localtime_r(&timestamp, &tm_time);
+
+    // The logfile's filename will have the date/time & pid in it
+    ostringstream time_pid_stream;
+    time_pid_stream.fill('0');
+    time_pid_stream << 1900+tm_time.tm_year
+                    << setw(2) << 1+tm_time.tm_mon
+                    << setw(2) << tm_time.tm_mday
+                    << '-'
+                    << setw(2) << tm_time.tm_hour
+                    << setw(2) << tm_time.tm_min
+                    << setw(2) << tm_time.tm_sec
+                    << '.'
+                    << GetMainThreadPid();
+    const string& time_pid_string = time_pid_stream.str();
+
+    if (base_filename_selected_) {
+      if (!CreateLogfile(time_pid_string)) {
+        perror("Could not create log file");
+        fprintf(stderr, "COULD NOT CREATE LOGFILE '%s'!\n",
+                time_pid_string.c_str());
+        return;
+      }
+    } else {
+      // If no base filename for logs of this severity has been set, use a
+      // default base filename of
+      // "<program name>.<hostname>.<user name>.log.<severity level>.".  So
+      // logfiles will have names like
+      // webserver.examplehost.root.log.INFO.19990817-150000.4354, where
+      // 19990817 is a date (1999 August 17), 150000 is a time (15:00:00),
+      // and 4354 is the pid of the logging process.  The date & time reflect
+      // when the file was created for output.
+      //
+      // Where does the file get put?  Successively try the directories
+      // "/tmp", and "."
+      string stripped_filename(
+          glog_internal_namespace_::ProgramInvocationShortName());
+      string hostname;
+      GetHostName(&hostname);
+
+      string uidname = MyUserName();
+      // We should not call CHECK() here because this function can be
+      // called after holding on to log_mutex. We don't want to
+      // attempt to hold on to the same mutex, and get into a
+      // deadlock. Simply use a name like invalid-user.
+      if (uidname.empty()) uidname = "invalid-user";
+
+      stripped_filename = stripped_filename+'.'+hostname+'.'
+                          +uidname+".log."
+                          +LogSeverityNames[severity_]+'.';
+      // We're going to (potentially) try to put logs in several different dirs
+      const vector<string> & log_dirs = GetLoggingDirectories();
+
+      // Go through the list of dirs, and try to create the log file in each
+      // until we succeed or run out of options
+      bool success = false;
+      for (vector<string>::const_iterator dir = log_dirs.begin();
+           dir != log_dirs.end();
+           ++dir) {
+        base_filename_ = *dir + "/" + stripped_filename;
+        if ( CreateLogfile(time_pid_string) ) {
+          success = true;
+          break;
+        }
+      }
+      // If we never succeeded, we have to give up
+      if ( success == false ) {
+        perror("Could not create logging file");
+        fprintf(stderr, "COULD NOT CREATE A LOGGINGFILE %s!",
+                time_pid_string.c_str());
+        return;
+      }
+    }
+
+    // Write a header message into the log file
+    ostringstream file_header_stream;
+    file_header_stream.fill('0');
+    file_header_stream << "Log file created at: "
+                       << 1900+tm_time.tm_year << '/'
+                       << setw(2) << 1+tm_time.tm_mon << '/'
+                       << setw(2) << tm_time.tm_mday
+                       << ' '
+                       << setw(2) << tm_time.tm_hour << ':'
+                       << setw(2) << tm_time.tm_min << ':'
+                       << setw(2) << tm_time.tm_sec << '\n'
+                       << "Running on machine: "
+                       << LogDestination::hostname() << '\n'
+                       << "Log line format: [IWEF]yyyymmdd hh:mm:ss.uuuuuu "
+                       << "threadid file:line] msg" << '\n';
+    const string& file_header_string = file_header_stream.str();
+
+    const int header_len = file_header_string.size();
+    fwrite(file_header_string.data(), 1, header_len, file_);
+    file_length_ += header_len;
+    bytes_since_flush_ += header_len;
+  }
+ 
+  // Write to LOG file
+  if ( !stop_writing ) {
+    // fwrite() doesn't return an error when the disk is full, for
+    // messages that are less than 4096 bytes. When the disk is full,
+    // it returns the message length for messages that are less than
+    // 4096 bytes. fwrite() returns 4096 for message lengths that are
+    // greater than 4096, thereby indicating an error.
+    errno = 0;
+    fwrite(message, 1, message_len, file_);
+    if ( FLAGS_stop_logging_if_full_disk &&
+         errno == ENOSPC ) {  // disk full, stop writing to disk
+      stop_writing = true;  // until the disk is
+      return;
+    } else {
+      file_length_ += message_len;
+      bytes_since_flush_ += message_len;
+    }
+  } else {
+    if ( CycleClock_Now() >= next_flush_time_ )
+      stop_writing = false;  // check to see if disk has free space.
+    return;  // no need to flush
+  }
+
+  // See important msgs *now*.  Also, flush logs at least every 10^6 chars,
+  // or every "FLAGS_logbufsecs" seconds.
+  if ( force_flush ||
+       (bytes_since_flush_ >= 1000000) ||
+       (CycleClock_Now() >= next_flush_time_) ) {
+    FlushUnlocked();
+#ifdef OS_LINUX
+    // Only consider files >= 3MiB
+    if (FLAGS_drop_log_memory && file_length_ >= (3 << 20)) {
+      // Don't evict the most recent 1-2MiB so as not to impact a tailer
+      // of the log file and to avoid page rounding issue on linux < 4.7
+      uint32 total_drop_length = (file_length_ & ~((1 << 20) - 1)) - (1 << 20);
+      uint32 this_drop_length = total_drop_length - dropped_mem_length_;
+      if (this_drop_length >= (2 << 20)) {
+        // Only advise when >= 2MiB to drop
+# if defined(__ANDROID__) && defined(__ANDROID_API__) && (__ANDROID_API__ < 21)
+        // 'posix_fadvise' introduced in API 21:
+        // * https://android.googlesource.com/platform/bionic/+/6880f936173081297be0dc12f687d341b86a4cfa/libc/libc.map.txt#732
+# else
+        posix_fadvise(fileno(file_), dropped_mem_length_, this_drop_length,
+                      POSIX_FADV_DONTNEED);
+# endif
+        dropped_mem_length_ = total_drop_length;
+      }
+    }
+#endif
+    // Perform clean up for old logs
+    if (log_cleaner_enabled_) {
+      const vector<string>& dirs = GetLoggingDirectories();
+      for (size_t i = 0; i < dirs.size(); i++) {
+        vector<string> logs = GetOverdueLogNames(dirs[i], log_cleaner_overdue_days_);
+        for (size_t j = 0; j < logs.size(); j++) {
+          static_cast<void>(unlink(logs[j].c_str()));
+        }
+      }
+    }
+  }
+}
+
+}  // namespace
+
+// Static log data space to avoid alloc failures in a LOG(FATAL)
+//
+// Since multiple threads may call LOG(FATAL), and we want to preserve
+// the data from the first call, we allocate two sets of space.  One
+// for exclusive use by the first thread, and one for shared use by
+// all other threads.
+static Mutex fatal_msg_lock;
+static CrashReason crash_reason;
+static bool fatal_msg_exclusive = true;
+static LogMessage::LogMessageData fatal_msg_data_exclusive;
+static LogMessage::LogMessageData fatal_msg_data_shared;
+
+#ifdef GLOG_THREAD_LOCAL_STORAGE
+// Static thread-local log data space to use, because typically at most one
+// LogMessageData object exists (in this case glog makes zero heap memory
+// allocations).
+static GLOG_THREAD_LOCAL_STORAGE bool thread_data_available = true;
+
+#ifdef HAVE_ALIGNED_STORAGE
+static GLOG_THREAD_LOCAL_STORAGE
+    std::aligned_storage<sizeof(LogMessage::LogMessageData),
+                         alignof(LogMessage::LogMessageData)>::type thread_msg_data;
+#else
+static GLOG_THREAD_LOCAL_STORAGE
+    char thread_msg_data[sizeof(void*) + sizeof(LogMessage::LogMessageData)];
+#endif  // HAVE_ALIGNED_STORAGE
+#endif  // defined(GLOG_THREAD_LOCAL_STORAGE)
+
+LogMessage::LogMessageData::LogMessageData()
+  : stream_(message_text_, LogMessage::kMaxLogMessageLen, 0) {
+}
+
+LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
+                       int ctr, void (LogMessage::*send_method)())
+    : allocated_(NULL) {
+  Init(file, line, severity, send_method);
+  data_->stream_.set_ctr(ctr);
+}
+
+LogMessage::LogMessage(const char* file, int line,
+                       const CheckOpString& result)
+    : allocated_(NULL) {
+  Init(file, line, GLOG_FATAL, &LogMessage::SendToLog);
+  stream() << "Check failed: " << (*result.str_) << " ";
+}
+
+LogMessage::LogMessage(const char* file, int line)
+    : allocated_(NULL) {
+  Init(file, line, GLOG_INFO, &LogMessage::SendToLog);
+}
+
+LogMessage::LogMessage(const char* file, int line, LogSeverity severity)
+    : allocated_(NULL) {
+  Init(file, line, severity, &LogMessage::SendToLog);
+}
+
+LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
+                       LogSink* sink, bool also_send_to_log)
+    : allocated_(NULL) {
+  Init(file, line, severity, also_send_to_log ? &LogMessage::SendToSinkAndLog :
+                                                &LogMessage::SendToSink);
+  data_->sink_ = sink;  // override Init()'s setting to NULL
+}
+
+LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
+                       vector<string> *outvec)
+    : allocated_(NULL) {
+  Init(file, line, severity, &LogMessage::SaveOrSendToLog);
+  data_->outvec_ = outvec; // override Init()'s setting to NULL
+}
+
+LogMessage::LogMessage(const char* file, int line, LogSeverity severity,
+                       string *message)
+    : allocated_(NULL) {
+  Init(file, line, severity, &LogMessage::WriteToStringAndLog);
+  data_->message_ = message;  // override Init()'s setting to NULL
+}
+
+void LogMessage::Init(const char* file,
+                      int line,
+                      LogSeverity severity,
+                      void (LogMessage::*send_method)()) {
+  allocated_ = NULL;
+  if (severity != GLOG_FATAL || !exit_on_dfatal) {
+#ifdef GLOG_THREAD_LOCAL_STORAGE
+    // No need for locking, because this is thread local.
+    if (thread_data_available) {
+      thread_data_available = false;
+#ifdef HAVE_ALIGNED_STORAGE
+      data_ = new (&thread_msg_data) LogMessageData;
+#else
+      const uintptr_t kAlign = sizeof(void*) - 1;
+
+      char* align_ptr =
+          reinterpret_cast<char*>(reinterpret_cast<uintptr_t>(thread_msg_data + kAlign) & ~kAlign);
+      data_ = new (align_ptr) LogMessageData;
+      assert(reinterpret_cast<uintptr_t>(align_ptr) % sizeof(void*) == 0);
+#endif
+    } else {
+      allocated_ = new LogMessageData();
+      data_ = allocated_;
+    }
+#else // !defined(GLOG_THREAD_LOCAL_STORAGE)
+    allocated_ = new LogMessageData();
+    data_ = allocated_;
+#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
+    data_->first_fatal_ = false;
+  } else {
+    MutexLock l(&fatal_msg_lock);
+    if (fatal_msg_exclusive) {
+      fatal_msg_exclusive = false;
+      data_ = &fatal_msg_data_exclusive;
+      data_->first_fatal_ = true;
+    } else {
+      data_ = &fatal_msg_data_shared;
+      data_->first_fatal_ = false;
+    }
+  }
+
+  stream().fill('0');
+  data_->preserved_errno_ = errno;
+  data_->severity_ = severity;
+  data_->line_ = line;
+  data_->send_method_ = send_method;
+  data_->sink_ = NULL;
+  data_->outvec_ = NULL;
+  WallTime now = WallTime_Now();
+  data_->timestamp_ = static_cast<time_t>(now);
+  localtime_r(&data_->timestamp_, &data_->tm_time_);
+  data_->usecs_ = static_cast<int32>((now - data_->timestamp_) * 1000000);
+
+  data_->num_chars_to_log_ = 0;
+  data_->num_chars_to_syslog_ = 0;
+  data_->basename_ = const_basename(file);
+  data_->fullname_ = file;
+  data_->has_been_flushed_ = false;
+
+  // If specified, prepend a prefix to each line.  For example:
+  //    I20201018 160715 f5d4fbb0 logging.cc:1153]
+  //    (log level, GMT year, month, date, time, thread_id, file basename, line)
+  // We exclude the thread_id for the default thread.
+  if (FLAGS_log_prefix && (line != kNoLogPrefix)) {
+    stream() << LogSeverityNames[severity][0]
+             << setw(4) << 1900+data_->tm_time_.tm_year
+             << setw(2) << 1+data_->tm_time_.tm_mon
+             << setw(2) << data_->tm_time_.tm_mday
+             << ' '
+             << setw(2) << data_->tm_time_.tm_hour  << ':'
+             << setw(2) << data_->tm_time_.tm_min   << ':'
+             << setw(2) << data_->tm_time_.tm_sec   << "."
+             << setw(6) << data_->usecs_
+             << ' '
+             << setfill(' ') << setw(5)
+             << static_cast<unsigned int>(GetTID()) << setfill('0')
+             << ' '
+             << data_->basename_ << ':' << data_->line_ << "] ";
+  }
+  data_->num_prefix_chars_ = data_->stream_.pcount();
+
+  if (!FLAGS_log_backtrace_at.empty()) {
+    char fileline[128];
+    snprintf(fileline, sizeof(fileline), "%s:%d", data_->basename_, line);
+#ifdef HAVE_STACKTRACE
+    if (!strcmp(FLAGS_log_backtrace_at.c_str(), fileline)) {
+      string stacktrace;
+      DumpStackTraceToString(&stacktrace);
+      stream() << " (stacktrace:\n" << stacktrace << ") ";
+    }
+#endif
+  }
+}
+
+LogMessage::~LogMessage() {
+  Flush();
+#ifdef GLOG_THREAD_LOCAL_STORAGE
+  if (data_ == static_cast<void*>(&thread_msg_data)) {
+    data_->~LogMessageData();
+    thread_data_available = true;
+  }
+  else {
+    delete allocated_;
+  }
+#else // !defined(GLOG_THREAD_LOCAL_STORAGE)
+  delete allocated_;
+#endif // defined(GLOG_THREAD_LOCAL_STORAGE)
+}
+
+int LogMessage::preserved_errno() const {
+  return data_->preserved_errno_;
+}
+
+ostream& LogMessage::stream() {
+  return data_->stream_;
+}
+
+// Flush buffered message, called by the destructor, or any other function
+// that needs to synchronize the log.
+void LogMessage::Flush() {
+  if (data_->has_been_flushed_ || data_->severity_ < FLAGS_minloglevel)
+    return;
+
+  data_->num_chars_to_log_ = data_->stream_.pcount();
+  data_->num_chars_to_syslog_ =
+    data_->num_chars_to_log_ - data_->num_prefix_chars_;
+
+  // Do we need to add a \n to the end of this message?
+  bool append_newline =
+      (data_->message_text_[data_->num_chars_to_log_-1] != '\n');
+  char original_final_char = '\0';
+
+  // If we do need to add a \n, we'll do it by violating the memory of the
+  // ostrstream buffer.  This is quick, and we'll make sure to undo our
+  // modification before anything else is done with the ostrstream.  It
+  // would be preferable not to do things this way, but it seems to be
+  // the best way to deal with this.
+  if (append_newline) {
+    original_final_char = data_->message_text_[data_->num_chars_to_log_];
+    data_->message_text_[data_->num_chars_to_log_++] = '\n';
+  }
+
+  // Prevent any subtle race conditions by wrapping a mutex lock around
+  // the actual logging action per se.
+  {
+    MutexLock l(&log_mutex);
+    (this->*(data_->send_method_))();
+    ++num_messages_[static_cast<int>(data_->severity_)];
+  }
+  LogDestination::WaitForSinks(data_);
+
+  if (append_newline) {
+    // Fix the ostrstream back how it was before we screwed with it.
+    // It's 99.44% certain that we don't need to worry about doing this.
+    data_->message_text_[data_->num_chars_to_log_-1] = original_final_char;
+  }
+
+  // If errno was already set before we enter the logging call, we'll
+  // set it back to that value when we return from the logging call.
+  // It happens often that we log an error message after a syscall
+  // failure, which can potentially set the errno to some other
+  // values.  We would like to preserve the original errno.
+  if (data_->preserved_errno_ != 0) {
+    errno = data_->preserved_errno_;
+  }
+
+  // Note that this message is now safely logged.  If we're asked to flush
+  // again, as a result of destruction, say, we'll do nothing on future calls.
+  data_->has_been_flushed_ = true;
+}
+
+// Copy of first FATAL log message so that we can print it out again
+// after all the stack traces.  To preserve legacy behavior, we don't
+// use fatal_msg_data_exclusive.
+static time_t fatal_time;
+static char fatal_message[256];
+
+void ReprintFatalMessage() {
+  if (fatal_message[0]) {
+    const int n = strlen(fatal_message);
+    if (!FLAGS_logtostderr) {
+      // Also write to stderr (don't color to avoid terminal checks)
+      WriteToStderr(fatal_message, n);
+    }
+    LogDestination::LogToAllLogfiles(GLOG_ERROR, fatal_time, fatal_message, n);
+  }
+}
+
+// L >= log_mutex (callers must hold the log_mutex).
+void LogMessage::SendToLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
+  static bool already_warned_before_initgoogle = false;
+
+  log_mutex.AssertHeld();
+
+  RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
+             data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
+
+  // Messages of a given severity get logged to lower severity logs, too
+
+  if (!already_warned_before_initgoogle && !IsGoogleLoggingInitialized()) {
+    const char w[] = "WARNING: Logging before InitGoogleLogging() is "
+                     "written to STDERR\n";
+    WriteToStderr(w, strlen(w));
+    already_warned_before_initgoogle = true;
+  }
+
+  // global flag: never log to file if set.  Also -- don't log to a
+  // file if we haven't parsed the command line flags to get the
+  // program name.
+  if (FLAGS_logtostderr || !IsGoogleLoggingInitialized()) {
+    ColoredWriteToStderr(data_->severity_,
+                         data_->message_text_, data_->num_chars_to_log_);
+
+    // this could be protected by a flag if necessary.
+    LogDestination::LogToSinks(data_->severity_,
+                               data_->fullname_, data_->basename_,
+                               data_->line_, &data_->tm_time_,
+                               data_->message_text_ + data_->num_prefix_chars_,
+                               (data_->num_chars_to_log_ -
+                                data_->num_prefix_chars_ - 1),
+                               data_->usecs_);
+  } else {
+
+    // log this message to all log files of severity <= severity_
+    LogDestination::LogToAllLogfiles(data_->severity_, data_->timestamp_,
+                                     data_->message_text_,
+                                     data_->num_chars_to_log_);
+
+    LogDestination::MaybeLogToStderr(data_->severity_, data_->message_text_,
+                                     data_->num_chars_to_log_);
+    LogDestination::MaybeLogToEmail(data_->severity_, data_->message_text_,
+                                    data_->num_chars_to_log_);
+    LogDestination::LogToSinks(data_->severity_,
+                               data_->fullname_, data_->basename_,
+                               data_->line_, &data_->tm_time_,
+                               data_->message_text_ + data_->num_prefix_chars_,
+                               (data_->num_chars_to_log_
+                                - data_->num_prefix_chars_ - 1),
+                               data_->usecs_);
+    // NOTE: -1 removes trailing \n
+  }
+
+  // If we log a FATAL message, flush all the log destinations, then toss
+  // a signal for others to catch. We leave the logs in a state that
+  // someone else can use them (as long as they flush afterwards)
+  if (data_->severity_ == GLOG_FATAL && exit_on_dfatal) {
+    if (data_->first_fatal_) {
+      // Store crash information so that it is accessible from within signal
+      // handlers that may be invoked later.
+      RecordCrashReason(&crash_reason);
+      SetCrashReason(&crash_reason);
+
+      // Store shortened fatal message for other logs and GWQ status
+      const int copy = min<int>(data_->num_chars_to_log_,
+                                sizeof(fatal_message)-1);
+      memcpy(fatal_message, data_->message_text_, copy);
+      fatal_message[copy] = '\0';
+      fatal_time = data_->timestamp_;
+    }
+
+    if (!FLAGS_logtostderr) {
+      for (int i = 0; i < NUM_SEVERITIES; ++i) {
+        if ( LogDestination::log_destinations_[i] )
+          LogDestination::log_destinations_[i]->logger_->Write(true, 0, "", 0);
+      }
+    }
+
+    // release the lock that our caller (directly or indirectly)
+    // LogMessage::~LogMessage() grabbed so that signal handlers
+    // can use the logging facility. Alternately, we could add
+    // an entire unsafe logging interface to bypass locking
+    // for signal handlers but this seems simpler.
+    log_mutex.Unlock();
+    LogDestination::WaitForSinks(data_);
+
+    const char* message = "*** Check failure stack trace: ***\n";
+    if (write(STDERR_FILENO, message, strlen(message)) < 0) {
+      // Ignore errors.
+    }
+    Fail();
+  }
+}
+
+void LogMessage::RecordCrashReason(
+    glog_internal_namespace_::CrashReason* reason) {
+  reason->filename = fatal_msg_data_exclusive.fullname_;
+  reason->line_number = fatal_msg_data_exclusive.line_;
+  reason->message = fatal_msg_data_exclusive.message_text_ +
+                    fatal_msg_data_exclusive.num_prefix_chars_;
+#ifdef HAVE_STACKTRACE
+  // Retrieve the stack trace, omitting the logging frames that got us here.
+  reason->depth = GetStackTrace(reason->stack, ARRAYSIZE(reason->stack), 4);
+#else
+  reason->depth = 0;
+#endif
+}
+
+#ifdef HAVE___ATTRIBUTE__
+# define ATTRIBUTE_NORETURN __attribute__((noreturn))
+#else
+# define ATTRIBUTE_NORETURN
+#endif
+
+#if defined(OS_WINDOWS)
+__declspec(noreturn)
+#endif
+static void logging_fail() ATTRIBUTE_NORETURN;
+
+static void logging_fail() {
+  abort();
+}
+
+typedef void (*logging_fail_func_t)() ATTRIBUTE_NORETURN;
+
+GOOGLE_GLOG_DLL_DECL
+logging_fail_func_t g_logging_fail_func = &logging_fail;
+
+void InstallFailureFunction(void (*fail_func)()) {
+  g_logging_fail_func = (logging_fail_func_t)fail_func;
+}
+
+void LogMessage::Fail() {
+  g_logging_fail_func();
+}
+
+// L >= log_mutex (callers must hold the log_mutex).
+void LogMessage::SendToSink() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
+  if (data_->sink_ != NULL) {
+    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
+               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
+    data_->sink_->send(data_->severity_, data_->fullname_, data_->basename_,
+                       data_->line_, &data_->tm_time_,
+                       data_->message_text_ + data_->num_prefix_chars_,
+                       (data_->num_chars_to_log_ -
+                        data_->num_prefix_chars_ - 1),
+                       data_->usecs_);
+  }
+}
+
+// L >= log_mutex (callers must hold the log_mutex).
+void LogMessage::SendToSinkAndLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
+  SendToSink();
+  SendToLog();
+}
+
+// L >= log_mutex (callers must hold the log_mutex).
+void LogMessage::SaveOrSendToLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
+  if (data_->outvec_ != NULL) {
+    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
+               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
+    // Omit prefix of message and trailing newline when recording in outvec_.
+    const char *start = data_->message_text_ + data_->num_prefix_chars_;
+    int len = data_->num_chars_to_log_ - data_->num_prefix_chars_ - 1;
+    data_->outvec_->push_back(string(start, len));
+  } else {
+    SendToLog();
+  }
+}
+
+void LogMessage::WriteToStringAndLog() EXCLUSIVE_LOCKS_REQUIRED(log_mutex) {
+  if (data_->message_ != NULL) {
+    RAW_DCHECK(data_->num_chars_to_log_ > 0 &&
+               data_->message_text_[data_->num_chars_to_log_-1] == '\n', "");
+    // Omit prefix of message and trailing newline when writing to message_.
+    const char *start = data_->message_text_ + data_->num_prefix_chars_;
+    int len = data_->num_chars_to_log_ - data_->num_prefix_chars_ - 1;
+    data_->message_->assign(start, len);
+  }
+  SendToLog();
+}
+
+// L >= log_mutex (callers must hold the log_mutex).
+void LogMessage::SendToSyslogAndLog() {
+#ifdef HAVE_SYSLOG_H
+  // Before any calls to syslog(), make a single call to openlog()
+  static bool openlog_already_called = false;
+  if (!openlog_already_called) {
+    openlog(glog_internal_namespace_::ProgramInvocationShortName(),
+            LOG_CONS | LOG_NDELAY | LOG_PID,
+            LOG_USER);
+    openlog_already_called = true;
+  }
+
+  // This array maps Google severity levels to syslog levels
+  const int SEVERITY_TO_LEVEL[] = { LOG_INFO, LOG_WARNING, LOG_ERR, LOG_EMERG };
+  syslog(LOG_USER | SEVERITY_TO_LEVEL[static_cast<int>(data_->severity_)], "%.*s",
+         int(data_->num_chars_to_syslog_),
+         data_->message_text_ + data_->num_prefix_chars_);
+  SendToLog();
+#else
+  LOG(ERROR) << "No syslog support: message=" << data_->message_text_;
+#endif
+}
+
+base::Logger* base::GetLogger(LogSeverity severity) {
+  MutexLock l(&log_mutex);
+  return LogDestination::log_destination(severity)->logger_;
+}
+
+void base::SetLogger(LogSeverity severity, base::Logger* logger) {
+  MutexLock l(&log_mutex);
+  LogDestination::log_destination(severity)->logger_ = logger;
+}
+
+// L < log_mutex.  Acquires and releases mutex_.
+int64 LogMessage::num_messages(int severity) {
+  MutexLock l(&log_mutex);
+  return num_messages_[severity];
+}
+
+// Output the COUNTER value. This is only valid if ostream is a
+// LogStream.
+ostream& operator<<(ostream &os, const PRIVATE_Counter&) {
+#ifdef DISABLE_RTTI
+  LogMessage::LogStream *log = static_cast<LogMessage::LogStream*>(&os);
+#else
+  LogMessage::LogStream *log = dynamic_cast<LogMessage::LogStream*>(&os);
+#endif
+  CHECK(log && log == log->self())
+      << "You must not use COUNTER with non-glog ostream";
+  os << log->ctr();
+  return os;
+}
+
+ErrnoLogMessage::ErrnoLogMessage(const char* file, int line,
+                                 LogSeverity severity, int ctr,
+                                 void (LogMessage::*send_method)())
+    : LogMessage(file, line, severity, ctr, send_method) {
+}
+
+ErrnoLogMessage::~ErrnoLogMessage() {
+  // Don't access errno directly because it may have been altered
+  // while streaming the message.
+  stream() << ": " << StrError(preserved_errno()) << " ["
+           << preserved_errno() << "]";
+}
+
+void FlushLogFiles(LogSeverity min_severity) {
+  LogDestination::FlushLogFiles(min_severity);
+}
+
+void FlushLogFilesUnsafe(LogSeverity min_severity) {
+  LogDestination::FlushLogFilesUnsafe(min_severity);
+}
+
+void SetLogDestination(LogSeverity severity, const char* base_filename) {
+  LogDestination::SetLogDestination(severity, base_filename);
+}
+
+void SetLogSymlink(LogSeverity severity, const char* symlink_basename) {
+  LogDestination::SetLogSymlink(severity, symlink_basename);
+}
+
+LogSink::~LogSink() {
+}
+
+void LogSink::WaitTillSent() {
+  // noop default
+}
+
+string LogSink::ToString(LogSeverity severity, const char* file, int line,
+                         const struct ::tm* tm_time,
+                         const char* message, size_t message_len, int32 usecs) {
+  ostringstream stream(string(message, message_len));
+  stream.fill('0');
+
+  stream << LogSeverityNames[severity][0]
+         << setw(4) << 1900+tm_time->tm_year
+         << setw(2) << 1+tm_time->tm_mon
+         << setw(2) << tm_time->tm_mday
+         << ' '
+         << setw(2) << tm_time->tm_hour << ':'
+         << setw(2) << tm_time->tm_min << ':'
+         << setw(2) << tm_time->tm_sec << '.'
+         << setw(6) << usecs
+         << ' '
+         << setfill(' ') << setw(5) << GetTID() << setfill('0')
+         << ' '
+         << file << ':' << line << "] ";
+
+  stream << string(message, message_len);
+  return stream.str();
+}
+
+void AddLogSink(LogSink *destination) {
+  LogDestination::AddLogSink(destination);
+}
+
+void RemoveLogSink(LogSink *destination) {
+  LogDestination::RemoveLogSink(destination);
+}
+
+void SetLogFilenameExtension(const char* ext) {
+  LogDestination::SetLogFilenameExtension(ext);
+}
+
+void SetStderrLogging(LogSeverity min_severity) {
+  LogDestination::SetStderrLogging(min_severity);
+}
+
+void SetEmailLogging(LogSeverity min_severity, const char* addresses) {
+  LogDestination::SetEmailLogging(min_severity, addresses);
+}
+
+void LogToStderr() {
+  LogDestination::LogToStderr();
+}
+
+namespace base {
+namespace internal {
+
+bool GetExitOnDFatal();
+bool GetExitOnDFatal() {
+  MutexLock l(&log_mutex);
+  return exit_on_dfatal;
+}
+
+// Determines whether we exit the program for a LOG(DFATAL) message in
+// debug mode.  It does this by skipping the call to Fail/FailQuietly.
+// This is intended for testing only.
+//
+// This can have some effects on LOG(FATAL) as well.  Failure messages
+// are always allocated (rather than sharing a buffer), the crash
+// reason is not recorded, the "gwq" status message is not updated,
+// and the stack trace is not recorded.  The LOG(FATAL) *will* still
+// exit the program.  Since this function is used only in testing,
+// these differences are acceptable.
+void SetExitOnDFatal(bool value);
+void SetExitOnDFatal(bool value) {
+  MutexLock l(&log_mutex);
+  exit_on_dfatal = value;
+}
+
+}  // namespace internal
+}  // namespace base
+
+// Shell-escaping as we need to shell out ot /bin/mail.
+static const char kDontNeedShellEscapeChars[] =
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+            "abcdefghijklmnopqrstuvwxyz"
+            "0123456789+-_.=/:,@";
+
+static string ShellEscape(const string& src) {
+  string result;
+  if (!src.empty() &&  // empty string needs quotes
+      src.find_first_not_of(kDontNeedShellEscapeChars) == string::npos) {
+    // only contains chars that don't need quotes; it's fine
+    result.assign(src);
+  } else if (src.find_first_of('\'') == string::npos) {
+    // no single quotes; just wrap it in single quotes
+    result.assign("'");
+    result.append(src);
+    result.append("'");
+  } else {
+    // needs double quote escaping
+    result.assign("\"");
+    for (size_t i = 0; i < src.size(); ++i) {
+      switch (src[i]) {
+        case '\\':
+        case '$':
+        case '"':
+        case '`':
+          result.append("\\");
+      }
+      result.append(src, i, 1);
+    }
+    result.append("\"");
+  }
+  return result;
+}
+
+
+// use_logging controls whether the logging functions LOG/VLOG are used
+// to log errors.  It should be set to false when the caller holds the
+// log_mutex.
+static bool SendEmailInternal(const char*dest, const char *subject,
+                              const char*body, bool use_logging) {
+  if (dest && *dest) {
+    if ( use_logging ) {
+      VLOG(1) << "Trying to send TITLE:" << subject
+              << " BODY:" << body << " to " << dest;
+    } else {
+      fprintf(stderr, "Trying to send TITLE: %s BODY: %s to %s\n",
+              subject, body, dest);
+    }
+
+    string cmd =
+        FLAGS_logmailer + " -s" +
+        ShellEscape(subject) + " " + ShellEscape(dest);
+    VLOG(4) << "Mailing command: " << cmd;
+
+    FILE* pipe = popen(cmd.c_str(), "w");
+    if (pipe != NULL) {
+      // Add the body if we have one
+      if (body)
+        fwrite(body, sizeof(char), strlen(body), pipe);
+      bool ok = pclose(pipe) != -1;
+      if ( !ok ) {
+        if ( use_logging ) {
+          LOG(ERROR) << "Problems sending mail to " << dest << ": "
+                     << StrError(errno);
+        } else {
+          fprintf(stderr, "Problems sending mail to %s: %s\n",
+                  dest, StrError(errno).c_str());
+        }
+      }
+      return ok;
+    } else {
+      if ( use_logging ) {
+        LOG(ERROR) << "Unable to send mail to " << dest;
+      } else {
+        fprintf(stderr, "Unable to send mail to %s\n", dest);
+      }
+    }
+  }
+  return false;
+}
+
+bool SendEmail(const char*dest, const char *subject, const char*body){
+  return SendEmailInternal(dest, subject, body, true);
+}
+
+static void GetTempDirectories(vector<string>* list) {
+  list->clear();
+#ifdef OS_WINDOWS
+  // On windows we'll try to find a directory in this order:
+  //   C:/Documents & Settings/whomever/TEMP (or whatever GetTempPath() is)
+  //   C:/TMP/
+  //   C:/TEMP/
+  //   C:/WINDOWS/ or C:/WINNT/
+  //   .
+  char tmp[MAX_PATH];
+  if (GetTempPathA(MAX_PATH, tmp))
+    list->push_back(tmp);
+  list->push_back("C:\\tmp\\");
+  list->push_back("C:\\temp\\");
+#else
+  // Directories, in order of preference. If we find a dir that
+  // exists, we stop adding other less-preferred dirs
+  const char * candidates[] = {
+    // Non-null only during unittest/regtest
+    getenv("TEST_TMPDIR"),
+
+    // Explicitly-supplied temp dirs
+    getenv("TMPDIR"), getenv("TMP"),
+
+    // If all else fails
+    "/tmp",
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE(candidates); i++) {
+    const char *d = candidates[i];
+    if (!d) continue;  // Empty env var
+
+    // Make sure we don't surprise anyone who's expecting a '/'
+    string dstr = d;
+    if (dstr[dstr.size() - 1] != '/') {
+      dstr += "/";
+    }
+    list->push_back(dstr);
+
+    struct stat statbuf;
+    if (!stat(d, &statbuf) && S_ISDIR(statbuf.st_mode)) {
+      // We found a dir that exists - we're done.
+      return;
+    }
+  }
+
+#endif
+}
+
+static vector<string>* logging_directories_list;
+
+const vector<string>& GetLoggingDirectories() {
+  // Not strictly thread-safe but we're called early in InitGoogle().
+  if (logging_directories_list == NULL) {
+    logging_directories_list = new vector<string>;
+
+    if ( !FLAGS_log_dir.empty() ) {
+      // A dir was specified, we should use it
+      logging_directories_list->push_back(FLAGS_log_dir.c_str());
+    } else {
+      GetTempDirectories(logging_directories_list);
+#ifdef OS_WINDOWS
+      char tmp[MAX_PATH];
+      if (GetWindowsDirectoryA(tmp, MAX_PATH))
+        logging_directories_list->push_back(tmp);
+      logging_directories_list->push_back(".\\");
+#else
+      logging_directories_list->push_back("./");
+#endif
+    }
+  }
+  return *logging_directories_list;
+}
+
+void TestOnly_ClearLoggingDirectoriesList() {
+  fprintf(stderr, "TestOnly_ClearLoggingDirectoriesList should only be "
+          "called from test code.\n");
+  delete logging_directories_list;
+  logging_directories_list = NULL;
+}
+
+void GetExistingTempDirectories(vector<string>* list) {
+  GetTempDirectories(list);
+  vector<string>::iterator i_dir = list->begin();
+  while( i_dir != list->end() ) {
+    // zero arg to access means test for existence; no constant
+    // defined on windows
+    if ( access(i_dir->c_str(), 0) ) {
+      i_dir = list->erase(i_dir);
+    } else {
+      ++i_dir;
+    }
+  }
+}
+
+void TruncateLogFile(const char *path, int64 limit, int64 keep) {
+#ifdef HAVE_UNISTD_H
+  struct stat statbuf;
+  const int kCopyBlockSize = 8 << 10;
+  char copybuf[kCopyBlockSize];
+  int64 read_offset, write_offset;
+  // Don't follow symlinks unless they're our own fd symlinks in /proc
+  int flags = O_RDWR;
+  // TODO(hamaji): Support other environments.
+#ifdef OS_LINUX
+  const char *procfd_prefix = "/proc/self/fd/";
+  if (strncmp(procfd_prefix, path, strlen(procfd_prefix))) flags |= O_NOFOLLOW;
+#endif
+
+  int fd = open(path, flags);
+  if (fd == -1) {
+    if (errno == EFBIG) {
+      // The log file in question has got too big for us to open. The
+      // real fix for this would be to compile logging.cc (or probably
+      // all of base/...) with -D_FILE_OFFSET_BITS=64 but that's
+      // rather scary.
+      // Instead just truncate the file to something we can manage
+      if (truncate(path, 0) == -1) {
+        PLOG(ERROR) << "Unable to truncate " << path;
+      } else {
+        LOG(ERROR) << "Truncated " << path << " due to EFBIG error";
+      }
+    } else {
+      PLOG(ERROR) << "Unable to open " << path;
+    }
+    return;
+  }
+
+  if (fstat(fd, &statbuf) == -1) {
+    PLOG(ERROR) << "Unable to fstat()";
+    goto out_close_fd;
+  }
+
+  // See if the path refers to a regular file bigger than the
+  // specified limit
+  if (!S_ISREG(statbuf.st_mode)) goto out_close_fd;
+  if (statbuf.st_size <= limit)  goto out_close_fd;
+  if (statbuf.st_size <= keep) goto out_close_fd;
+
+  // This log file is too large - we need to truncate it
+  LOG(INFO) << "Truncating " << path << " to " << keep << " bytes";
+
+  // Copy the last "keep" bytes of the file to the beginning of the file
+  read_offset = statbuf.st_size - keep;
+  write_offset = 0;
+  int bytesin, bytesout;
+  while ((bytesin = pread(fd, copybuf, sizeof(copybuf), read_offset)) > 0) {
+    bytesout = pwrite(fd, copybuf, bytesin, write_offset);
+    if (bytesout == -1) {
+      PLOG(ERROR) << "Unable to write to " << path;
+      break;
+    } else if (bytesout != bytesin) {
+      LOG(ERROR) << "Expected to write " << bytesin << ", wrote " << bytesout;
+    }
+    read_offset += bytesin;
+    write_offset += bytesout;
+  }
+  if (bytesin == -1) PLOG(ERROR) << "Unable to read from " << path;
+
+  // Truncate the remainder of the file. If someone else writes to the
+  // end of the file after our last read() above, we lose their latest
+  // data. Too bad ...
+  if (ftruncate(fd, write_offset) == -1) {
+    PLOG(ERROR) << "Unable to truncate " << path;
+  }
+
+ out_close_fd:
+  close(fd);
+#else
+  LOG(ERROR) << "No log truncation support.";
+#endif
+}
+
+void TruncateStdoutStderr() {
+#ifdef HAVE_UNISTD_H
+  int64 limit = MaxLogSize() << 20;
+  int64 keep = 1 << 20;
+  TruncateLogFile("/proc/self/fd/1", limit, keep);
+  TruncateLogFile("/proc/self/fd/2", limit, keep);
+#else
+  LOG(ERROR) << "No log truncation support.";
+#endif
+}
+
+
+// Helper functions for string comparisons.
+#define DEFINE_CHECK_STROP_IMPL(name, func, expected)                   \
+  string* Check##func##expected##Impl(const char* s1, const char* s2,   \
+                                      const char* names) {              \
+    bool equal = s1 == s2 || (s1 && s2 && !func(s1, s2));               \
+    if (equal == expected) return NULL;                                 \
+    else {                                                              \
+      ostringstream ss;                                                 \
+      if (!s1) s1 = "";                                                 \
+      if (!s2) s2 = "";                                                 \
+      ss << #name " failed: " << names << " (" << s1 << " vs. " << s2 << ")"; \
+      return new string(ss.str());                                      \
+    }                                                                   \
+  }
+DEFINE_CHECK_STROP_IMPL(CHECK_STREQ, strcmp, true)
+DEFINE_CHECK_STROP_IMPL(CHECK_STRNE, strcmp, false)
+DEFINE_CHECK_STROP_IMPL(CHECK_STRCASEEQ, strcasecmp, true)
+DEFINE_CHECK_STROP_IMPL(CHECK_STRCASENE, strcasecmp, false)
+#undef DEFINE_CHECK_STROP_IMPL
+
+int posix_strerror_r(int err, char *buf, size_t len) {
+  // Sanity check input parameters
+  if (buf == NULL || len <= 0) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  // Reset buf and errno, and try calling whatever version of strerror_r()
+  // is implemented by glibc
+  buf[0] = '\000';
+  int old_errno = errno;
+  errno = 0;
+  char *rc = reinterpret_cast<char *>(strerror_r(err, buf, len));
+
+  // Both versions set errno on failure
+  if (errno) {
+    // Should already be there, but better safe than sorry
+    buf[0]     = '\000';
+    return -1;
+  }
+  errno = old_errno;
+
+  // POSIX is vague about whether the string will be terminated, although
+  // is indirectly implies that typically ERANGE will be returned, instead
+  // of truncating the string. This is different from the GNU implementation.
+  // We play it safe by always terminating the string explicitly.
+  buf[len-1] = '\000';
+
+  // If the function succeeded, we can use its exit code to determine the
+  // semantics implemented by glibc
+  if (!rc) {
+    return 0;
+  } else {
+    // GNU semantics detected
+    if (rc == buf) {
+      return 0;
+    } else {
+      buf[0] = '\000';
+#if defined(OS_MACOSX) || defined(OS_FREEBSD) || defined(OS_OPENBSD)
+      if (reinterpret_cast<intptr_t>(rc) < sys_nerr) {
+        // This means an error on MacOSX or FreeBSD.
+        return -1;
+      }
+#endif
+      strncat(buf, rc, len-1);
+      return 0;
+    }
+  }
+}
+
+string StrError(int err) {
+  char buf[100];
+  int rc = posix_strerror_r(err, buf, sizeof(buf));
+  if ((rc < 0) || (buf[0] == '\000')) {
+    snprintf(buf, sizeof(buf), "Error number %d", err);
+  }
+  return buf;
+}
+
+LogMessageFatal::LogMessageFatal(const char* file, int line) :
+    LogMessage(file, line, GLOG_FATAL) {}
+
+LogMessageFatal::LogMessageFatal(const char* file, int line,
+                                 const CheckOpString& result) :
+    LogMessage(file, line, result) {}
+
+LogMessageFatal::~LogMessageFatal() {
+    Flush();
+    LogMessage::Fail();
+}
+
+namespace base {
+
+CheckOpMessageBuilder::CheckOpMessageBuilder(const char *exprtext)
+    : stream_(new ostringstream) {
+  *stream_ << exprtext << " (";
+}
+
+CheckOpMessageBuilder::~CheckOpMessageBuilder() {
+  delete stream_;
+}
+
+ostream* CheckOpMessageBuilder::ForVar2() {
+  *stream_ << " vs. ";
+  return stream_;
+}
+
+string* CheckOpMessageBuilder::NewString() {
+  *stream_ << ")";
+  return new string(stream_->str());
+}
+
+}  // namespace base
+
+template <>
+void MakeCheckOpValueString(std::ostream* os, const char& v) {
+  if (v >= 32 && v <= 126) {
+    (*os) << "'" << v << "'";
+  } else {
+    (*os) << "char value " << (short)v;
+  }
+}
+
+template <>
+void MakeCheckOpValueString(std::ostream* os, const signed char& v) {
+  if (v >= 32 && v <= 126) {
+    (*os) << "'" << v << "'";
+  } else {
+    (*os) << "signed char value " << (short)v;
+  }
+}
+
+template <>
+void MakeCheckOpValueString(std::ostream* os, const unsigned char& v) {
+  if (v >= 32 && v <= 126) {
+    (*os) << "'" << v << "'";
+  } else {
+    (*os) << "unsigned char value " << (unsigned short)v;
+  }
+}
+
+void InitGoogleLogging(const char* argv0) {
+  glog_internal_namespace_::InitGoogleLoggingUtilities(argv0);
+}
+
+void ShutdownGoogleLogging() {
+  glog_internal_namespace_::ShutdownGoogleLoggingUtilities();
+  LogDestination::DeleteLogDestinations();
+  delete logging_directories_list;
+  logging_directories_list = NULL;
+}
+
+void EnableLogCleaner(int overdue_days) {
+  log_cleaner_enabled_ = true;
+
+  // Setting overdue_days to 0 day should not be allowed!
+  // Since all logs will be deleted immediately, which will cause troubles.
+  if (overdue_days > 0) {
+    log_cleaner_overdue_days_ = overdue_days;
+  }
+}
+
+void DisableLogCleaner() {
+  log_cleaner_enabled_ = false;
+}
+
+_END_GOOGLE_NAMESPACE_