Method: RGen::Util::FileCacheMap#load_data

Defined in:
lib/rgen/util/file_cache_map.rb

#load_data(key_path, options = {}) ⇒ Object

load data associated with file key_path returns :invalid in case either the associated file or the cache file has changed

options:

:invalidation_reasons:
  an array which will receive symbols indicating why the cache is invalid:
  :no_cachefile, :cachefile_corrupted, :keyfile_changed



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# File 'lib/rgen/util/file_cache_map.rb', line 35

def load_data(key_path, options={})
  reasons = options[:invalidation_reasons] || []
  cf = cache_file(key_path)
  result = nil
  begin
    File.open(cf, "rb") do |f|
      header = f.read(41)
      if !header
        reasons << :cachefile_corrupted
        return :invalid
      end
      checksum = header[0..39]
      data = f.read
      if calc_sha1(data) == checksum
        if calc_sha1_keydata(key_path) == data[0..39]
          result = data[41..-1]
        else
          reasons << :keyfile_changed
          result = :invalid
        end
      else
        reasons << :cachefile_corrupted
        result = :invalid
      end
    end 
  rescue Errno::ENOENT
    reasons << :no_cachefile
    result = :invalid 
  end
  result
end