Class: RedParse::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/redparse/cache.rb

Instance Method Summary collapse

Constructor Details

#initialize(*params) ⇒ Cache

Returns a new instance of Cache.



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# File 'lib/redparse/cache.rb', line 4

def initialize *params
  @callersfile=Digest::SHA2.hexdigest params.join(',')
  @homedir=find_home+"/.redparse/"
  Dir.mkdir @homedir unless File.exist? @homedir
  Dir.mkdir cachedir unless File.exist? cachedir
  saved_digest= File.open(@homedir+"/parserdigest","rb"){|fd| fd.read.chomp } if File.exist?(@homedir+"/parserdigest")
  actual_digest= @@saved_parser_digest ||= redparse_rb_hexdigest
  if saved_digest!=actual_digest
    File.unlink(*all_entry_files)        #flush cache
    File.open(@homedir+"/parserdigest","wb"){|fd| fd.puts actual_digest } #update saved digest
  end
  retire_old_entries
end

Instance Method Details

#all_entry_files ⇒ Object 



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# File 'lib/redparse/cache.rb', line 26

def all_entry_files
  Dir[@homedir+"*"].select{|fn| 
    File.directory? fn 
  }.map{|dirname|
    Dir[dirname+"/*"]
  }.flatten
end

#cachedir ⇒ Object 



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# File 'lib/redparse/cache.rb', line 18

def cachedir
  @homedir+@callersfile+"/"
end

#get(input) ⇒ Object 



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# File 'lib/redparse/cache.rb', line 108

def get input
  hash=hash_of_input input
  cachefile=cachedir+hash
  if File.exist? cachefile
    result=File.open(cachefile,"rb"){|fd| 
      line=fd.readline
      fd.rewind
      if /#encoded with Ron\n/i===line
        begin
          require 'ron'
          Ron.load fd.read
        rescue Exception
          return nil
        end
      else
        begin
          Marshal.load fd
        rescue Exception=>e              
          warn "#{e.class}: #{e}"
          warn "cache read failed for:\n#{input}"
          return nil
        end
      end
    }

    begin
      t=Time.now
      File.utime(t,t,cachefile)
    rescue Exception
      File.open(cachefile,"a"){|fd| } #touch cache date
    end
    return result
  end
rescue EOFError
  return nil
end

#hash_of_input(input) ⇒ Object 



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# File 'lib/redparse/cache.rb', line 100

def hash_of_input input
  if IO===input
    hexdigest_of_file input
  else
    Digest::SHA2.hexdigest input
  end
end

#put(input, result) ⇒ Object 



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# File 'lib/redparse/cache.rb', line 145

def put input,result
  hash=hash_of_input input
  File.open(cachedir+hash, "wb"){|fd|
    begin
      Thread.current["Marshal.ignore_sclass"]=true
      Marshal.dump(result,fd)
    rescue TypeError=>e #dump failed
      File.unlink cachedir+hash
      begin
        require 'ron'
        File.open(cachedir+hash, "wb"){|fd2|
          fd2.write "#encoded with Ron\n"
          fd2.write Ron.dump(result)
        }
      rescue Exception
        return
      end
    ensure
      Thread.current["Marshal.ignore_sclass"]=nil
    end
  }
rescue Exception=>e #dump failed
  warn "#{e.class}: #{e}"
  warn "cache write failed for:\n#{result.inspect}"
  File.unlink cachedir+hash
end