class Logger::LogDevice

# File lib/logger.rb, line 543
def initialize(log = nil, opt = {})
  @dev = @filename = @shift_age = @shift_size = nil
  @mutex = LogDeviceMutex.new
  if log.respond_to?(:write) and log.respond_to?(:close)
    @dev = log
  else
    @dev = open_logfile(log)
    @dev.sync = true
    @filename = log
    @shift_age = opt[:shift_age] || 7
    @shift_size = opt[:shift_size] || 1048576
  end
end

# File lib/logger.rb, line 578
def close
  begin
    @mutex.synchronize do
      @dev.close rescue nil
    end
  rescue Exception
    @dev.close rescue nil
  end
end

# File lib/logger.rb, line 557
def write(message)
  begin
    @mutex.synchronize do
      if @shift_age and @dev.respond_to?(:stat)
        begin
          check_shift_log
        rescue
          warn("log shifting failed. #{$!}")
        end
      end
      begin
        @dev.write(message)
      rescue
        warn("log writing failed. #{$!}")
      end
    end
  rescue Exception => ignored
    warn("log writing failed. #{ignored}")
  end
end

# File lib/logger.rb, line 613
def add_log_header(file)
  file.write(
    "# Logfile created on %s by %s\n" % [Time.now.to_s, Logger::ProgName]
  ) if file.size == 0
end

# File lib/logger.rb, line 621
def check_shift_log
  if @shift_age.is_a?(Integer)
    # Note: always returns false if '0'.
    if @filename && (@shift_age > 0) && (@dev.stat.size > @shift_size)
      lock_shift_log { shift_log_age }
    end
  else
    now = Time.now
    period_end = previous_period_end(now)
    if @dev.stat.mtime <= period_end
      lock_shift_log { shift_log_period(period_end) }
    end
  end
end

# File lib/logger.rb, line 598
def create_logfile(filename)
  begin
    logdev = open(filename, (File::WRONLY | File::APPEND | File::CREAT | File::EXCL))
    logdev.flock(File::LOCK_EX)
    logdev.sync = true
    add_log_header(logdev)
    logdev.flock(File::LOCK_UN)
  rescue Errno::EEXIST
    # file is created by another process
    logdev = open_logfile(filename)
    logdev.sync = true
  end
  logdev
end

# File lib/logger.rb, line 716
def eod(t)
  Time.mktime(t.year, t.month, t.mday, 23, 59, 59)
end

# File lib/logger.rb, line 637
def lock_shift_log
  yield
end

# File lib/logger.rb, line 590
def open_logfile(filename)
  begin
    open(filename, (File::WRONLY | File::APPEND))
  rescue Errno::ENOENT
    create_logfile(filename)
  end
end

# File lib/logger.rb, line 703
def previous_period_end(now)
  case @shift_age
  when /^daily$/
    eod(now - 1 * SiD)
  when /^weekly$/
    eod(now - ((now.wday + 1) * SiD))
  when /^monthly$/
    eod(now - now.mday * SiD)
  else
    now
  end
end

# File lib/logger.rb, line 672
def shift_log_age
  (@shift_age-3).downto(0) do |i|
    if FileTest.exist?("#{@filename}.#{i}")
      File.rename("#{@filename}.#{i}", "#{@filename}.#{i+1}")
    end
  end
  @dev.close rescue nil
  File.rename("#{@filename}", "#{@filename}.0")
  @dev = create_logfile(@filename)
  return true
end

# File lib/logger.rb, line 684
def shift_log_period(period_end)
  postfix = period_end.strftime("%Y%m%d") # YYYYMMDD
  age_file = "#{@filename}.#{postfix}"
  if FileTest.exist?(age_file)
    # try to avoid filename crash caused by Timestamp change.
    idx = 0
    # .99 can be overridden; avoid too much file search with 'loop do'
    while idx < 100
      idx += 1
      age_file = "#{@filename}.#{postfix}.#{idx}"
      break unless FileTest.exist?(age_file)
    end
  end
  @dev.close rescue nil
  File.rename("#{@filename}", age_file)
  @dev = create_logfile(@filename)
  return true
end