Class: AbstractBuilder::LazyCache

Inherits:
Object
  • Object
show all
Defined in:
lib/abstract_builder/lazy_cache.rb

Instance Method Summary collapse

Constructor Details

#initialize(driver) ⇒ LazyCache

Returns a new instance of LazyCache.



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# File 'lib/abstract_builder/lazy_cache.rb', line 3

def initialize(driver)
  @cache = Hash.new { |h, k| h[k] = {} }
  @driver = driver
end

Instance Method Details

#add(key, options, &block) ⇒ Object 



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# File 'lib/abstract_builder/lazy_cache.rb', line 8

def add(key, options, &block)
  cache[options][key] = block
end

#resolve ⇒ Object 



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# File 'lib/abstract_builder/lazy_cache.rb', line 12

def resolve
  resolved = []

  # Fail-fast if there is no items to be computed.
  return resolved if cache.empty?

  # We can't add new items during interation, so iterate through a clone
  # that will allow us to add new items.
  previous = cache.clone
  cache.clear

  # Keys are grouped by options and because of that, fetch_multi will use
  # the same options for the same group of keys.
  previous.each do |options, group|
    result = driver.fetch_multi(*group.keys, options) do |group_key|
      [group[group_key].call, *resolve]
    end

    # Since the fetch_multi returns { cache_key => value }, we need to
    # discard the cache key and merge only the values.
    resolved.concat result.values.flatten(1)
  end

  resolved
end