Class: Rabl::Digestor

Inherits:
ActionView::Digestor
  • Object
show all
Defined in:
lib/rabl/digestor.rb

Class Method Summary collapse

Class Method Details

.digest(name, format, finder, options = {}) ⇒ Object 



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# File 'lib/rabl/digestor.rb', line 6

def self.digest(name:, finder:, **options)

  options.assert_valid_keys(:dependencies, :partial)

  cache_key = ([ name ].compact + Array.wrap(options[:dependencies])).join('.')

  # this is a correctly done double-checked locking idiom
  # (Concurrent::Map's lookups have volatile semantics)
  finder.digest_cache[cache_key] || @@digest_monitor.synchronize do
    finder.digest_cache.fetch(cache_key) do # re-check under lock
      begin
        # Prevent re-entry or else recursive templates will blow the stack.
        # There is no need to worry about other threads seeing the +false+ value,
        # as they will then have to wait for this thread to let go of the @@digest_monitor lock.

        pre_stored = finder.digest_cache.put_if_absent(cache_key, false).nil? # put_if_absent returns nil on insertion

        finder.digest_cache[cache_key] = stored_digest = Digestor.new(name, finder, options).digest
      ensure
        # something went wrong or ActionView::Resolver.caching? is false, make sure not to corrupt the @@cache
        finder.digest_cache.delete_pair(cache_key, false) if pre_stored && !stored_digest
      end
    end
  end
end