class Sprockets::StaticAsset

other binary files.
any processing or concatenation. These are typical images and
`StaticAsset`s are used for files that are served verbatim without

def self.serialized_attributes

Define extra attributes to be serialized. 
def self.serialized_attributes
  super + %w( content_type mtime length digest )
end

def body

Returns file contents as its `body`. 
def body
  # File is read everytime to avoid memory bloat of large binary files
  pathname.open('rb') { |f| f.read }
end

def fresh?

digest to the inmemory model.
Checks if Asset is fresh by comparing the actual mtime and 
def fresh?
  # Check current mtime and digest
  dependency_fresh?('path' => pathname, 'mtime' => mtime, 'hexdigest' => digest)
end

def initialize(environment, logical_path, pathname, digest = nil) 

def initialize(environment, logical_path, pathname, digest = nil)
  super(environment, logical_path, pathname)
  @digest = digest
  load!
end

def load! 

def load!
  content_type
  mtime
  length
  digest
end

def to_path

Implemented for Rack SendFile support. 
def to_path
  pathname.to_s
end

def to_s

`to_s` is aliased to body since static assets can't have any dependencies. 
def to_s
  body
end

def write_to(filename, options = {})

Save asset to disk. 
def write_to(filename, options = {})
  # Gzip contents if filename has '.gz'
  options[:compress] ||= File.extname(filename) == '.gz'
  if options[:compress]
    # Open file and run it through `Zlib`
    pathname.open('rb') do |rd|
      File.open("#{filename}+", 'wb') do |wr|
        gz = Zlib::GzipWriter.new(wr, Zlib::BEST_COMPRESSION)
        buf = ""
        while rd.read(16384, buf)
          gz.write(buf)
        end
        gz.close
      end
    end
  else
    # If no compression needs to be done, we can just copy it into place.
    FileUtils.cp(pathname, "#{filename}+")
  end
  # Atomic write
  FileUtils.mv("#{filename}+", filename)
  # Set mtime correctly
  File.utime(mtime, mtime, filename)
  nil
ensure
  # Ensure tmp file gets cleaned up
  FileUtils.rm("#{filename}+") if File.exist?("#{filename}+")
end